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Confidential Draft Submission No. 2 submitted to the Securities and Exchange Commission on January 29, 2014. This draft registration statement has not been publicly filed with the Securities and Exchange Commission and all information herein remains strictly confidential.

Registration No. 333-            

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-1

REGISTRATION STATEMENT

UNDER THE SECURITIES ACT OF 1933

SCYNEXIS, Inc.

(Exact name of registrant as specified in its charter)

3501 C Tricenter Boulevard

Durham, North Carolina 27713

(919) 544-8600

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Yves J. Ribeill, Ph.D.

President and Chief Executive Officer

SCYNEXIS, Inc.

3501 C Tricenter Boulevard

Durham, North Carolina 27713

(919) 544-8600

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Approximate date of commencement of proposed sale to the public: As soon as practicable after the effective date of this Registration Statement.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box.  ¨

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ¨

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ¨

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

CALCULATION OF REGISTRATION FEE

The Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the Registration Statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

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The information in this preliminary prospectus is not complete and may be changed. These securities may not be sold until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell nor does it seek an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED JANUARY 29, 2014

PRELIMINARY PROSPECTUS

            Shares

SCYNEXIS, Inc.

Common Stock

We are offering             shares of our common stock. This is our initial public offering and no public market currently exists for our common stock. We expect the initial public offering price to be between $         and $         per share. We have applied to list our common stock on the NASDAQ Global Market under the symbol “SCYX.”

Investing in our common stock involves a high degree of risk. Please read “Risk Factors” beginning on page 9 of this prospectus.

We are an “emerging growth company,” as defined in the Jumpstart Our Business Startups Act of 2012, and are subject to reduced public company reporting requirements.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

Delivery of the shares of common stock is expected to be made on or about                     , 2014. We have granted the underwriters an option for a period of 30 days to purchase an additional                     shares of our common stock to cover over-allotments. If the underwriters exercise the option in full, the total underwriting discounts and commissions payable by us will be $                , and the total proceeds to us, before expenses, will be $                .

RBC CAPITAL MARKETS

Prospectus dated                     , 2014

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We and the underwriters have not authorized anyone to provide any information or to make any representations other than those contained in this prospectus or in any free writing prospectuses prepared by or on behalf of us or to which we have referred you. We take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. This prospectus is an offer to sell only the shares offered hereby, but only under circumstances and in jurisdictions where it is lawful to do so. The information contained in this prospectus is accurate only as of its date regardless of the time of delivery of this prospectus or of any sale of common stock.

Until and including                     , 2014 (the 25th day after the date of this prospectus), all dealers effecting transactions in these securities, whether or not participating in this offering, may be required to deliver a prospectus. This is in addition to a dealer’s obligation to deliver a prospectus when acting as an underwriter and with respect to an unsold allotment or subscription.

Neither we nor the underwriters have done anything that would permit this offering or possession or distribution of this prospectus in any jurisdiction where action for that purpose is required, other than in the United States. Persons who come into possession of this prospectus and any free writing prospectus in jurisdictions outside the United States are required to inform themselves about and to observe any restrictions as to this offering and the distribution of this prospectus and any free writing prospectus applicable to that jurisdiction.

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RISK FACTORS

Investing in our common stock involves a high degree of risk. Before you invest in our common stock, you should carefully consider the following risks, as well as general economic and business risks and all of the other information contained in this prospectus. Any of the following risks could have a material adverse effect on our business, operating results and financial condition and cause the trading price of our common stock to decline, which would cause you to lose all or part of your investment. When determining whether to invest, you should also refer to the other information contained in this prospectus, including our financial statements and the related notes thereto.

Risks Relating to Our Financial Condition and Need for Additional Capital

We have never been profitable, we have no products approved for commercial sale, and to date we have not generated any revenue from product sales. As a result, our ability to curtail our losses and reach profitability is unproven, and we may never achieve or sustain profitability.

We are not profitable and do not expect to be profitable in the foreseeable future. We have incurred net losses in each year since our inception, including net losses of approximately $8.7 million, $11.5 million and $10.2 million for the nine months ended September 30, 2013, and for the years ended December 31, 2012 and 2011, respectively. As of September 30, 2013, we had an accumulated deficit of approximately $91.5 million. Although we have generated revenues through our contract research and development services, these revenues have not been sufficient to support our business, and so in addition we have financed our operations through the sale of convertible preferred stock and convertible debt. We intend to devote a majority of our financial resources to the development of SCY-078, our lead product candidate, and to a much lesser extent to development of product candidates from our cyclophilin inhibitor platform. We have not generated any revenue from product sales. The report of our independent registered public accounting firm on our financial statements for the year ended December 31, 2012, includes an explanatory paragraph relating to our ability to continue as a going concern. We have suffered substantial losses from operations and require additional financing. Ultimately we need to generate additional revenues and attain profitable operations. These factors raise substantial doubt about our ability to continue as a going concern.

We expect to continue to incur significant expenses and increasing operating losses for the foreseeable future. The net losses we incur may fluctuate significantly from quarter to quarter. We anticipate that our expenses will increase substantially as we:

In addition, our expenses could increase if we are required by the U.S. Food and Drug Administration, or the FDA, to perform studies in addition to, or that are larger than, those that we currently expect.

As a result of the foregoing, we expect to experience net losses and negative cash flows for the foreseeable future, and we are unable to predict when, or if, we will be able to achieve profitability. Our

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losses and negative cash flows have had, and will continue to have, an adverse effect on our stockholders’ equity, financial position and working capital.

We expect a number of factors to cause our operating results to fluctuate on a quarterly and annual basis, which may make it difficult to predict our future performance.

Our financial condition and operating results have varied significantly in the past and will continue to fluctuate from quarter to quarter or year to year due to a variety of factors, many of which are beyond our control. The following factors relating to our business, as well as factors described elsewhere in this prospectus, may contribute to these fluctuations:

Due to the various factors mentioned above, and others, the results of any quarterly or annual periods should not be relied upon as indications of future operating performance.

We may continue to require substantial additional capital, and if we are unable to raise capital when needed we would be forced to delay, reduce or eliminate our development program for SCY-078.

Developing pharmaceutical products, including conducting preclinical studies and clinical trials, is expensive. If the FDA requires that we perform additional studies beyond those that we currently expect, our expenses could increase beyond what we currently anticipate and the timing of any potential product approval may be delayed. We estimate that the net proceeds from this offering will be approximately $         million, assuming an initial public offering price of $         per share, the midpoint of the price range set forth on the cover page of this prospectus, after deducting underwriting discounts and commissions and estimated expenses payable by us. We believe that the net proceeds from this offering will be sufficient to

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meet our anticipated operating requirements through             . However, changing circumstances may cause us to consume capital more rapidly than we currently anticipate. We may need to raise additional funds from the issuance of equity and/or debt securities or otherwise obtain funding through strategic alliances or collaborations with third parties. In any event, we will require additional capital to complete development of, to seek regulatory approval for and, if approval is obtained, to commercialize SCY-078 and any future product candidates we may seek to develop. Raising funds in the current economic environment, when the capital markets have been affected by the global recession, may present additional challenges.

If we are required to secure additional financing, the additional fundraising efforts may divert our management from our day-to-day activities, which may adversely affect our ability to develop and commercialize SCY-078 and any future product candidates we may seek to develop. In addition, we cannot guarantee that financing will be available in sufficient amounts or on terms acceptable to us, if at all. If we are unable to raise additional capital when required or on acceptable terms, we may be required to:

If we are required to conduct additional fundraising activities and we are unable to raise additional capital in sufficient amounts or on terms acceptable to us, we will be prevented from pursuing development and commercialization efforts, which will have a material adverse effect on our business, operating results and prospects.

Risks Relating to the Development, Regulatory Approval and Commercialization

of Our Product Candidates For Human Use

Historically we have been primarily a contract research and development services company devoting a majority of our resources and efforts to providing research and development services to other companies, and we are only now shifting our focus to developing our own drug candidate SCY-078.

We were spun out from Aventis S.A., or Aventis, in 2000 as a chemistry and animal health services company, providing contract research services to third parties. Since then, we have derived substantially all of our revenue from providing these services to human and animal health companies to assist them in developing their own drug candidates. In the course of providing these services, we have leveraged the expertise to develop our own proprietary compounds, including a platform of cyclophilin inhibitors, among them SCY-635. In 2013, under the contract with Merck Sharp & Dohme Corp., or Merck, a subsidiary of Merck & Co., Inc., Merck exclusively licensed SCY-078 to us in the field of human health and in conjunction with that license transferred to us the investigational new drug application pending with the FDA and related regulatory responsibilities, as well as all data Merck had developed for the compound, plus active pharmaceutical ingredients and tablets. In 2014, Merck assigned the patents to us related to SCY-078 that it had exclusively licensed to us.

Although we have conducted Phase 1 and Phase 2 studies of SCY-635, our cyclophilin inhibitor, we only acquired the rights to develop SCY-078, our lead drug candidate for the treatment of invasive fungal infections, in May 2013. We do not have a significant history of developing our own drug candidates, and we have not brought any drug candidates to market, which makes it difficult to assess our ability to develop and commercialize SCY-078 and any future product candidates we may seek to develop or commercialize.

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We cannot be certain that SCY-078 will receive regulatory approval, and without regulatory approval we will not be able to market SCY-078. Regulatory approval is a lengthy, expensive and uncertain process.

Our ability to generate significant revenue related to SCY-078 sales will depend on the successful development and regulatory approval of SCY-078. We expect that the earliest that we could obtain regulatory approval of SCY-078 and commence commercialization of SCY-078 will be several years from now, if at all.

We currently have no products approved for sale and we cannot guarantee that we will ever have marketable products. The development and commercialization of a product candidate, including preclinical and clinical testing, manufacturing, quality systems, labeling, approval, record-keeping, selling, promotion, marketing and distribution of products, is subject to extensive regulation by the FDA in the United States and regulatory authorities in other countries, with regulations differing from country to country. We are not permitted to market product candidates in the United States until and unless we receive approval of an NDA from the FDA. We have not submitted an NDA for SCY-078. Obtaining approval of an NDA is a lengthy, expensive and uncertain process. An NDA must include extensive preclinical and clinical data and supporting information to establish the product candidate’s safety and effectiveness for each indication. The approval application must also include significant information regarding the chemistry, manufacturing and controls for the product. The regulatory development and review process typically takes years to complete, involves numerous uncertainties and the potential for concerns to emerge late in the development process, and approval is never guaranteed. Even if a product is approved, the FDA may limit the indications for which the product may be used, include extensive warnings on the product labeling or require costly ongoing requirements for post-marketing clinical studies and surveillance or other risk management measures to monitor the safety or efficacy of the product candidate. Markets outside of the United States also have requirements for approval of drug candidates with which we must comply prior to marketing. Obtaining regulatory approval for marketing of a product candidate in one country does not ensure we will be able to obtain regulatory approval in other countries, but a failure or delay in obtaining regulatory approval in one country may have a negative effect on the regulatory process in other countries. Also, any regulatory approval of a product candidate, once obtained, may be withdrawn. If SCY-078 or any of our other wholly-owned or partnered product candidates do not receive regulatory approval, we may not be able to generate sufficient revenue to become profitable or to continue our operations. Moreover, the filing of our NDA or the receipt of regulatory approval does not assure commercial success of any approved product.

Although the oral form of SCY-078 has been granted Qualified Infectious Disease Product status, this does not guarantee that the length of the FDA review process will be significantly shorter than otherwise, or that SCY-078 will ultimately be approved by the FDA.

We applied to the FDA for, and received, the designation of the oral form of SCY-078 as a Qualified Infectious Disease Product, or QIDP, under the Generating Antibiotic Incentive Now Act, or GAIN Act. We are submitting an additional application for the IV form of SCY-078 which we anticipate will be granted within the 60 day review period. There is no guarantee that the IV form of SCY-078 will be granted. We anticipate that the QIDP designation will provide, among other benefits, an overall increased level of communication with the FDA during the development process as a fast track product, priority review once a NDA is submitted, and, if SCY-078 is approved for its proposed use and awarded five years of exclusivity as a new chemical entity, or NCE, SCY-078 will be eligible for a ten year period of data exclusivity, comprising five years of NCE exclusivity plus an additional five years as a designated QIDP. This exclusivity period should protect SCY-078 from being referenced in an abbreviated new drug application, or ANDA, in support of a generic drug, or a 505(b)(2) new drug application for a follow-on product until the expiration of the

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exclusivity period (which may be shortened by one year if an ANDA or 505(b)(2) applicant seeks to challenge any of the patents that claim SCY-078). However, the primary framework of the GAIN Act became effective July 9, 2012, and as a relatively new law there is limited precedent for the way in which it will be implemented. Receipt of QIDP designation in practice may not result in a faster development process, review or approval compared to drugs considered for approval under conventional FDA procedures and does not assure ultimate approval by the FDA or related exclusivity benefits.

Delays in the commencement, enrollment and completion of clinical trials could result in increased costs to us and delay or limit our ability to obtain regulatory approval for SCY-078 or any future product candidates.

We do not know whether clinical trials of SCY-078 or any future product candidates we may seek to develop will be allowed to commence or, if commenced, will be completed on schedule or at all. The commencement, enrollment and completion of clinical trials can be delayed for a variety of reasons, including:

In addition, a clinical trial may be suspended or terminated by us, our current or any future partners, the FDA or other regulatory authorities due to a number of factors, including:

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If we are required to conduct additional clinical trials or other testing of SCY-078 or any future product candidates we may seek to develop, we may be delayed in obtaining, or may not be able to obtain, marketing approval for these product candidates.

In addition, if our current or any future partners have rights to and responsibility for development of SCY-078 or any future product candidates, they may fail to meet their obligations to develop and commercialize the product candidates, including clinical trials for these product candidates.

Changes in regulatory requirements and guidance may occur and we or any of our partners may be required by appropriate regulatory authorities to amend clinical trial protocols to reflect these changes. Amendments may require us or any of our partners to resubmit clinical trial protocols to independent review boards for re-examination, which may impact the costs, timing or successful completion of a clinical trial. If we or any of our partners experience delays in the completion of, or if we or our partners terminate, clinical trials, the commercial prospects for SCY-078 and any future product candidates we may seek to develop will be harmed, and our ability to generate revenue from sales of these product candidates will be prevented or delayed. In addition, many of the factors that cause, or lead to, a delay in the commencement or completion of clinical trials may also ultimately lead to the denial of regulatory approval of a product candidate.

Clinical failure can occur at any stage of clinical development. Because the results of earlier clinical trials are not necessarily predictive of future results, any product candidate we or our current or potential future partners advance through clinical trials may not have favorable results in later clinical trials or receive regulatory approval.

Clinical failure can occur at any stage of our clinical development. Clinical trials may produce negative or inconclusive results, and we or our partners may decide, or regulators may require us, to conduct additional clinical or preclinical testing. In addition, data obtained from tests are susceptible to varying interpretations, and regulators may not interpret data as favorably as we do, which may delay, limit or prevent regulatory approval. Success in preclinical testing and early clinical trials does not ensure that later clinical trials will generate the same results or otherwise provide adequate data to demonstrate the efficacy and safety of a product candidate. Frequently, product candidates that have shown promising results in early clinical trials have subsequently suffered significant setbacks in later clinical trials. In addition, the design of a clinical trial can determine whether its results will support approval of a product application, or approval of a supplemental application to add a new indication or other changes and flaws or shortcomings in the design of a clinical trial may not become apparent until the clinical trial is well advanced. We have limited experience in designing clinical trials and may be unable to design and execute a clinical trial to support regulatory approval, or approval of supplemental applications for new indications or other changes. Further, clinical trials of potential products often reveal that it is not practical or feasible to continue development efforts. If SCY-078 or any future product candidates are found to be unsafe or lack efficacy, we or our collaborators will not be able to obtain regulatory approval for them and our business would be harmed. For example, if the results of our planned Phase 2 and Phase 3 clinical trials of SCY-078 do not achieve, to the satisfaction of regulators, the primary efficacy endpoints and demonstrate an acceptable level of safety, the prospects for approval of SCY-078 would be materially and adversely affected. A number of companies in the pharmaceutical industry, including those with greater resources and experience than us, have suffered significant setbacks in Phase 2 and Phase 3 clinical trials, even after seeing promising results in earlier clinical trials.

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In some instances, there can be significant variability in safety and/or efficacy results between different trials of the same product candidate due to numerous factors, including differences in trial protocols and design, differences in size and type of the patient populations, adherence to the dosing regimen and the rate of dropout among clinical trial participants. Further, the patients taking SCY-078 often have other significant medical issues, such as organ transplants, cancer or other conditions in which their immune systems are depressed, which makes it difficult to measure the effect of SCY-078 in the presence of these medical issues. We do not know whether any Phase 2, Phase 3 or other clinical trials we or any partners may conduct will demonstrate consistent and/or adequate efficacy and safety to obtain regulatory approval to market SCY-078 and any future product candidates we may seek to develop.

We have limited experience in conducting Phase 2 and Phase 3 clinical trials and have never submitted an NDA before, and we may be unable to do so for SCY-078 or any future product candidate we may seek to develop.

Merck completed seven Phase 1 clinical trials of SCY-078, and we are planning to conduct Phase 2 and Phase 3 clinical trials of SCY-078. The conduct of successful Phase 2 and Phase 3 clinical trials is essential in obtaining regulatory approval, and the submission of a successful NDA is a complicated process. We have limited experience in preparing and submitting regulatory filings, have previously only sponsored one Phase 2 clinical trial, and have not previously sponsored any Phase 3 clinical trials nor have we ever submitted an NDA before. Consequently, we may be unable to successfully and efficiently execute and complete these planned clinical trials in a way that is acceptable to the FDA and leads to an NDA submission, acceptance and approval of SCY-078 or any future product candidate we may seek to develop. We may require more time and incur greater costs than our competitors and may not succeed in obtaining regulatory approvals of product candidates that we may seek to develop. In addition, failure to commence or complete, or delays in, our planned clinical trials would prevent us from or delay us in commercializing SCY-078 or any future product candidate we may develop.

We have not yet finalized the protocol for our planned Phase 2 study or studies of SCY-078, and are still in discussions with the FDA regarding anticipated indications and study endpoints.

Following the transfer by Merck to us of ownership and responsibility for the clinical development and NDA related to SCY-078, we assessed the regulatory history and initiated discussions with the FDA to obtain clarity on several open questions regarding the clinical development plan for SCY-078. Our most recent meeting with the FDA was in September 2013, and while we obtained feedback at this meeting, there are still some open questions under consideration by the FDA and our Phase 2 protocol is still being finalized. We do not know when, if at all, we will be able to finalize the protocol.

The environment in which our regulatory submissions may be reviewed changes over time, which may make it more difficult to obtain regulatory approval of any of our product candidates we may seek to develop or commercialize.

The environment in which our regulatory submissions are reviewed changes over time. For example, average review times at the FDA for NDAs have fluctuated over the last ten years, and we cannot predict the review time for any submission with any regulatory authorities. Review times can be affected by a variety of factors, including budget and funding levels and statutory, regulatory and policy changes. Moreover, in light of widely publicized events concerning the safety risk of certain drug products, regulatory authorities, members of Congress, the Government Accountability Office, medical professionals and the general public have raised concerns about potential drug safety issues. These events have resulted in the withdrawal of drug products, revisions to drug labeling that further limit use of the drug products and establishment of risk evaluation and mitigation strategies that may, for instance, restrict distribution of drug

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products. The increased attention to drug safety issues may result in a more cautious approach by the FDA to clinical trials. Data from preclinical studies and clinical trials may receive greater scrutiny with respect to safety, which may make the FDA or other regulatory authorities more likely to terminate clinical trials before completion, or require longer or additional clinical trials that may result in substantial additional expense, a delay or failure in obtaining approval or approval for a more limited indication than originally sought.

In addition, data obtained from preclinical studies and clinical trials are subject to different interpretations, which could delay, limit or prevent regulatory review or approval of product candidates. Changes in FDA personnel responsible for review of our submissions could also impact the manner in which our data are viewed. Furthermore, regulatory attitudes towards the data and results required to demonstrate safety and efficacy can change over time and can be affected by many factors, such as the emergence of new information, including on other products, policy changes and agency funding, staffing and leadership. We do not know whether future changes to the regulatory environment will be favorable or unfavorable to our business prospects.

If SCY-078 or any other future product candidates for which we receive regulatory approval do not achieve broad market acceptance, the revenue that is generated from their sales will be limited.

The commercial success of SCY-078 or any other product candidates we may seek to develop will depend upon the acceptance of these products candidates among physicians, patients, the medical community and healthcare payors. The degree of market acceptance of product candidates will depend on a number of factors, including:

If SCY-078 or any future product candidates we may seek to develop are approved, but do not achieve an adequate level of acceptance by physicians, healthcare payors and patients, sufficient revenue may not be generated from these product candidates, and we may not become or remain profitable. In addition, efforts to educate the medical community and third-party payors on the benefits of our product candidates may require significant resources and may never be successful.

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A significant use of anti-fungal drugs is treatment due to the presence of symptoms before diagnosis of the invasive fungal infections, and if a diagnostic tool is developed for the quick diagnosis of invasive fungal infections, the number of treatments using anti-fungal drugs may decrease significantly, decreasing the potential market for SCY-078.

We believe that a large portion of the treatments using anti-fungal drugs are administered when symptoms of invasive fungal infections are present but a diagnosis of the infection has not yet been made, due to the quick and potentially fatal progression of invasive fungal infections. If a diagnostic tool is developed for the quick diagnosis of invasive fungal infections, then the need to treat in advance of diagnosis of invasive fungal infections may be significantly diminished, which will reduce the potential market for SCY-078 in the event that we are able to obtain FDA approval of SCY-078. Moreover, if a fast and accurate test of the susceptibility of a fungal infection to generically available treatments is developed and widely adopted, the market for SCY-078 may suffer.

If invasive fungi develop resistance to SCY-078, our business will be harmed.

One or more strains of invasive fungi may develop resistance to SCY-078, either because our hypothesis of the mechanism of action is incorrect or because a strain of fungi undergoes some unforeseen genetic mutation that permits it to survive. Since we expect lack of resistance to be a major factor in the commercialization of SCY-078, the development of such resistance would have a major adverse impact on the acceptability and sales of SCY-078.

If we are unable to develop a formulation of SCY-078 that is delivered by intravenous, or IV, therapy SCY-078 may not achieve broad market acceptance and sales will be limited.

Current invasive fungal infection treatment regimens typically involve initial administration of treatments as an IV infusion, with a step down to an oral formulation of the same or a similar medication to complete the course of treatment on an out-patient basis. We believe that providing both the IV and oral formulations will be beneficial to doctors who prefer to start treatment of patients in a hospital setting with an IV therapy and then switch them to an oral formulation of the same medication. We currently have an oral form of SCY-078, and intend to develop an IV formulation. If we are unable to successfully develop and achieve regulatory approval for our IV formulation of SCY-078, or are delayed in developing and obtaining regulatory approval for our IV formulation of SCY-078, our lead product candidate may not achieve, or may be delayed in achieving, broad market acceptance and sales will be limited.

Our product candidates may have undesirable side effects that may delay or prevent marketing approval, or, if approval is received, require them to be taken off the market or otherwise limit their sales.

It is impossible to predict when or if SCY-078 or any other product candidate we may seek to develop will prove effective or safe or will receive marketing approval. Unforeseen side effects from any product candidates could arise either during clinical development or, if approved, after the product has been marketed. For example, the most frequently noted adverse effects reported as associated with SCY-078 treatment in the seven Phase 1 studies of SCY-078 conducted to date were diarrhea, abdominal pain, headache, nausea, fatigue, increased orthostatic heart rate, abnormal GI sounds, vomiting and dizziness. To date there have been two serious adverse events reported in clinical trials of SCY-078: one subject was diagnosed with a metastatic carcinoid tumor which was not considered to be related to SCY-078 by the investigator; and one subject experienced significant liver function test increases which were considered to be related to SCY-078. Preclinical findings in the future could trigger the need to evaluate or monitor for specific potential safety concerns in clinical trials. The results of future clinical trials may show that SCY-078 and any future product candidates we may seek to develop cause undesirable or unacceptable side

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effects, which could interrupt, delay or halt clinical trials, resulting in delay of, or failure to obtain, marketing approval from the FDA and other regulatory authorities, or may lead us to abandon their development altogether.

Even if SCY-078 or any future product candidate we may seek to develop receives marketing approval, we or others may subsequently identify undesirable or unacceptable side effects caused by these products, in which case:

Any of these events could prevent us or our current or potential future partners from achieving or maintaining market acceptance of the affected product or could substantially increase commercialization costs and expenses, which in turn could delay or prevent us from generating significant revenue from the sale of products.

We have never marketed a drug before, and if we are unable to establish an effective sales force and marketing infrastructure or enter into acceptable third-party sales and marketing or licensing arrangements, we may not be able to successfully commercialize SCY-078 and any future product candidates we may seek to develop.

We currently do not have any sales, distribution and marketing capabilities, the development of which will require substantial resources and will be time consuming. The costs incurred in the development of these capabilities, either internally or through a third-party contract sales organization, would be incurred in advance of any approval of a product candidate. In addition, we may not be able to hire a sales force in the United States that is sufficient in size or has adequate expertise in the medical markets that we intend to target. If we are unable to establish our sales force and marketing capability, our operating results may be adversely affected. In addition, we plan to enter into sales and marketing or licensing arrangements with third parties for international sales of any approved products. If we are unable to enter into or maintain any such arrangements on acceptable terms, or at all, we may be unable to market and sell SCY-078 and any future product candidates we may seek to develop in these markets.

We expect that SCY-078 and any future product candidates we may seek to develop will face competition, and most of our competitors have significantly greater resources than we do.

The pharmaceutical industry is highly competitive, with a number of established, large pharmaceutical companies, as well as many smaller companies. There are many foreign and domestic pharmaceutical companies, biotechnology companies, public and private universities, government agencies and research organizations actively engaged in research and development of products that may target the same markets as SCY-078 and any future product candidates we may seek to develop. We expect any products we develop to compete on the basis of, among other things, product efficacy, price, lack of significant adverse side

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effects and convenience and ease of treatment. For example, SCY-078 will compete against current leading anti-fungal drugs, including voriconazole from the azole class, caspofungin from the echinocandin class, and liposomal amphotericin B from the polyenes class.

Compared to us, many of our competitors in the anti-fungal market have, and potential competitors for any future product candidates we may seek to develop may have, substantially greater:

As a result of these factors, our competitors and potential competitors may obtain regulatory approval of their products more rapidly than we do. Our competitors and potential competitors may also develop drugs that are more effective, more widely used and less costly than ours and may also be more successful than us in manufacturing and marketing their products and maintaining compliance with ongoing regulatory compliance.

Reimbursement decisions by third-party payors may have an adverse effect on pricing and market acceptance in the United States. If there is not sufficient reimbursement for our products, it is less likely that our products will be purchased by patients and/or providers.

Successful commercialization of pharmaceutical products usually depends on the availability of adequate coverage and reimbursement from third-party payors, including commercial insurers and, under certain circumstances, federal and state healthcare programs. Patients and/or healthcare providers who purchase drugs generally rely on third-party payors to reimburse all or part of the costs associated with such products. As such, adequate coverage and reimbursement from third-party payors can be essential to new product acceptance and may have an effect on pricing.

Because SCY-078 is not currently commercially available, we do not know the extent to which it will be reimbursed if it is approved by the FDA. If we choose to bring other product candidates to market, they will be subject to similar uncertainty. We believe that SCY-078 and any other product candidates that are brought to market are less likely to be purchased by patients and/or providers if they are not adequately reimbursed by third-party payors.

Furthermore, the market for our product candidates may depend on access to third-party payors’ drug formularies, or lists of medications for which third-party payors provide coverage and reimbursement. Industry competition to be included in such formularies results in downward pricing pressures on pharmaceutical companies. Third-party payors may refuse to include a particular branded drug in their formularies when a competing generic product is available. The adoption of certain payment methodologies by third-party payors may limit our ability to profit from the sale of SCY-078. For example, under Medicare, hospitals are reimbursed under an inpatient prospective payment system. This pricing methodology provides a single payment amount to hospitals based on a given diagnosis-related group. As a result, with respect to Medicare reimbursement for services in the hospital inpatient setting, hospitals could have a financial incentive to use the least expensive drugs for the treatment of invasive fungal infections,

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particularly the IV formulations of these drugs, as they are typically administered in the hospital, which may significantly impact our ability to charge a premium for SCY-078.

All third-party payors, whether governmental or commercial, are developing increasingly sophisticated methods of controlling healthcare costs, including mechanisms to encourage the use of generic drugs. Congress has also considered policies to lower the reimbursement formulas in federal and state healthcare programs. Furthermore, coverage of, and reimbursement for, drugs can differ significantly from payor to payor and may require significant time and resources to obtain. In addition, new laws or regulations could impact future coverage and reimbursement.

Healthcare policy changes, including the Affordable Care Act, may have a material adverse effect on us.

In recent years, there have been numerous initiatives on the federal and state levels for comprehensive reforms affecting the payment for, the availability of and reimbursement for healthcare services in the United States, including pharmaceutical products. These initiatives have ranged from proposals to fundamentally change federal and state healthcare reimbursement programs, including providing comprehensive healthcare coverage to the public under governmental funded programs, to minor modifications to existing programs.

In March 2010, Congress enacted the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act, or the Affordable Care Act. The Affordable Care Act is designed to expand access to affordable health insurance, control healthcare spending, and improve healthcare quality. The law includes provisions to tie Medicare provider reimbursement to healthcare quality and incentives, mandatory compliance programs, enhanced transparency disclosure requirements, increased funding and initiatives to address fraud and abuse, and incentives to state Medicaid programs to expand their coverage and services. It also imposes an annual tax on pharmaceutical manufacturers or importers who sell “branded prescription drugs.” Implementation of the Affordable Care Act is occurring on an ongoing basis, and it is unclear what effect the Affordable Care Act or other state proposals may have on our business.

In addition to the Affordable Care Act, there will continue to be proposals by legislators at both the federal and state levels, regulators and third-party payors to keep drug costs down. Certain of these changes could impose limitations on the prices we will be able to charge for any products that are approved or the amounts of reimbursement available for these products from governmental agencies or third-party payors or may increase the tax requirements for life sciences companies such as ours. We anticipate that the Affordable Care Act and other future healthcare reform proposals could have a material adverse effect on our industry, and may limit our ability to commercialize SCY-078 and any future product candidates we may seek to develop and/or invest in new development.

We expect that a portion of the market for SCY-078 and any other product candidates we may seek to develop will be outside the United States. However, our product candidates may never receive approval or be commercialized outside of the United States.

Before we or any commercial partners can market and commercialize any product candidates outside of the United States, there are numerous and varying regulatory requirements of other countries that will apply. Research and marketing authorization procedures vary among countries and can involve additional product testing and administrative review periods. The marketing authorization process in other countries may include all of the risks detailed above regarding failure to obtain FDA approval in the United States as well as other risks. Regulatory approval in one country does not ensure regulatory approval in another, but a failure or delay in obtaining regulatory approval in one country, or identification of potential safety concerns in one country, may have a negative effect on the regulatory process in others. Failure to obtain

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regulatory approval in other countries or any delay or setback in obtaining such approval could have the same adverse effects detailed above regarding FDA approval in the United States. As described above, such effects include the risks that:

Foreign countries may have requirements for marketing authorization holders or distributors to have a legal or physical presence in that country, and consideration of and compliance with these requirements may result in additional time and expense before we can pursue or obtain marketing authorization in foreign jurisdictions. If we do receive approval in other countries, we may enter into sales and marketing arrangements with third parties for international sales of any approved products.

Even if SCY-078 or any other future product candidates we may seek to develop receive regulatory approval, we may still face future development and regulatory difficulties.

Even if regulatory approval is obtained for SCY-078 or any other future product candidates we may seek to develop, regulatory authorities may still impose significant restrictions on a product’s indicated uses or marketing or impose ongoing requirements for potentially costly post-approval studies. Given the number of high profile adverse safety events with certain drug products, regulatory authorities may require, as a condition of approval, costly risk evaluation and mitigation strategies, which may include safety surveillance, restricted distribution and use, patient education, enhanced labeling, expedited reporting of certain adverse events, pre-approval of promotional materials and restrictions on direct-to-consumer advertising. For example, any labeling approved for any of our product candidates may include a restriction on the term of its use, or it may not include one or more intended indications. Furthermore, any new legislation addressing drug safety issues could result in delays or increased costs during the period of product development, clinical trials and regulatory review and approval, as well as increased costs to assure compliance with any new post-approval regulatory requirements. Any of these restrictions or requirements could force us or our partners to conduct costly studies.

SCY-078 and any other future product candidates we may seek to develop will also be subject to ongoing regulatory requirements for the packaging, storage, advertising, promotion, record-keeping and submission of safety and other post-market information on the drug. In addition, approved products, manufacturers and manufacturers’ facilities are required to comply with extensive FDA requirements, including ensuring that quality control and manufacturing procedures conform to current Good Manufacturing Practices, or cGMP. As such, we and our contract manufacturers, which we will be responsible for overseeing and monitoring for compliance, are subject to continual review and periodic inspections to assess compliance with cGMP. Accordingly, we and others with whom we work must continue to expend time, money and effort in all areas of regulatory compliance, including manufacturing, production and quality control. The FDA may hold us responsible for any deficiencies or noncompliance of our contract manufacturers in relation to SCY-078 and any other future product candidates we may seek to develop. Failure to follow cGMP can result in products being deemed adulterated, which carries significant legal implications. We will also be required to engage in pharmacovigilance activities and report certain adverse reactions and production problems, if any, to the FDA and to comply with certain requirements

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concerning advertising and promotion for products. Promotional communications with respect to prescription drugs are subject to a variety of legal and regulatory restrictions and must be consistent with the information in the product’s approved label. As such, we may not promote products for indications or uses for which they do not have approval. Failure to comply with FDA advertising and promotion standards, which are often subject to interpretation by regulators, may result in a wide range of exposure and liability for us.

If a regulatory agency discovers previously unknown problems with a product, such as adverse events of unanticipated severity or frequency, or problems with the facility where the product is manufactured or disagrees with the promotion, marketing or labeling of a product, a regulatory agency may impose restrictions on that product or us, including requiring withdrawal of the product from the market. If the manufacturing or marketing of products fail to comply with applicable regulatory requirements, a regulatory agency may:

Non-compliance may also open a company to potential whistleblower lawsuits, and the potential for liability under the False Claims Act.

Pharmaceutical companies are subject to significant ongoing regulatory obligations and oversight, which may result in significant additional expense and limit our ability to commercialize our products.

We are subject to regulation by other regional, national, state and local agencies, including the Department of Justice, the Office of Inspector General of the U.S. Department of Health and Human Services and other regulatory bodies. Violations of any of the foregoing requirements could result in penalties being assessed against us.

The federal Anti-Kickback Statute prohibits, among other things, knowingly and willfully offering, paying, soliciting, or receiving remuneration to induce or in return for purchasing, leasing, ordering or arranging for the purchase, lease or order of any healthcare item or service reimbursable under Medicare, Medicaid or other federally financed healthcare programs. This statute has been interpreted to apply to arrangements between pharmaceutical companies on one hand and prescribers, purchasers and formulary managers on the other. The Affordable Care Act, among other things, clarified that a person or entity need not have actual knowledge of the federal Anti-Kickback Statute or specific intent to violate it. In addition, the Affordable Care Act amended the federal civil False Claims Act to provide that a claim, including items

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or services resulting from a violation of the federal anti-kickback statute, constitutes a false or fraudulent claim for purposes of the federal civil False Claims Act. There are a number of statutory exceptions and regulatory safe harbors protecting certain common activities from prosecution or other regulatory sanctions, however, the exceptions and safe harbors are drawn narrowly, and practices that do not fit squarely within an exception or safe harbor may be subject to scrutiny.

The federal civil False Claims Act prohibits any person from knowingly presenting, or causing to be presented, claims for payment of government funds that are false or fraudulent or knowingly making, or causing to be made, a false record or statement material to a false or fraudulent claim to avoid, decrease or conceal an obligation to pay money to the federal government. Many pharmaceutical and other healthcare companies have been investigated and have reached substantial financial settlements with the federal government under these laws for a variety of alleged marketing activities, including providing free product to customers with the expectation that the customers would bill federal programs for the product; providing consulting fees, grants, free travel, and other benefits to physicians to induce them to prescribe the company’s products; and inflating prices reported to private price publication services, which are used to set drug payment rates under government healthcare programs. Companies have been prosecuted for causing false claims to be submitted because of the marketing of their products for unapproved uses. Pharmaceutical and other healthcare companies have also been prosecuted on other legal theories of Medicare and Medicaid fraud.

The majority of states also have statutes or regulations similar to the federal Anti-Kickback Statute and federal civil False Claims Act, which apply to items and services reimbursed under Medicaid and other state programs, or, in several states, apply regardless of the payor. Some of these states also prohibit certain marketing related activities including the provision of gifts, meals, or other items to certain health care providers. In addition, California, Connecticut, Nevada, and Massachusetts require pharmaceutical companies to implement compliance programs or marketing codes.

Compliance with various federal and state laws is difficult and time consuming, and companies that violate them may face substantial penalties. The potential sanctions include civil monetary penalties, exclusion of a company’s products from reimbursement under government programs, criminal fines and imprisonment. Because of the breadth of these laws and the lack of extensive legal guidance in the form of regulations or court decisions, it is possible that some of our business activities or those of our commercial partners could be subject to challenge under one or more of these laws. Such a challenge could have a material adverse effect on our business and financial condition and growth prospects.

We could become subject to government investigations and related subpoenas. Such subpoenas are often associated with previously filed qui tam actions, or lawsuits filed under seal under the federal civil False Claims Act. Qui tam actions are brought by private plaintiffs suing on behalf of the federal government for alleged federal civil False Claims Act violations. The time and expense associated with responding to such subpoenas, and any related qui tam or other actions, may be extensive, and we cannot predict the results of our review of the responsive documents and underlying facts or the results of such actions. Responding to government investigations, defending any claims raised, and any resulting fines, restitution, damages and penalties, settlement payments or administrative actions, as well as any related actions brought by stockholders or other third parties, could have a material impact on our reputation, business and financial condition and divert the attention of our management from operating our business.

The number and complexity of both federal and state laws continues to increase, and additional governmental resources are being added to enforce these laws and to prosecute companies and individuals who are believed to be violating them. In particular, the Affordable Care Act includes a number of provisions aimed at strengthening the government’s ability to pursue federal Anti-Kickback Statute and federal False Claims Act cases against pharmaceutical manufacturers and other healthcare entities, including substantially increased funding for healthcare fraud enforcement activities, enhanced investigative powers,

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and amendments to the federal False Claims Act that make it easier for the government and whistleblowers to pursue cases for alleged kickback and false claim violations. Responding to a government investigation or enforcement action would be expensive and time-consuming, and could have a material adverse effect on our business and financial condition and growth prospects.

If we fail to comply with applicable federal, state, or local regulatory requirements, we could be subject to a range of regulatory actions that could affect our ability to commercialize our products and could harm or prevent sales of any affected products that we are able to commercialize, or could substantially increase the costs and expenses of commercializing and marketing our products. Any threatened or actual government enforcement action could also generate adverse publicity and require that we devote substantial resources that could otherwise be used in other aspects of our business.

Regulations, guidelines and recommendations published by various government agencies and organizations may affect the use of SCY-078 and any future product candidates we may seek to develop.

Government agencies may issue regulations and guidelines directly applicable to us, our partners or our potential future partners and our product candidates. In addition, professional societies, practice management groups, private health/science foundations and organizations involved in various diseases from time to time publish guidelines or recommendations to the healthcare and patient communities. These various sorts of recommendations may relate to such matters as product usage, dosage, route of administration and use of related or competing therapies. Changes to these recommendations or other guidelines advocating alternative therapies could result in decreased use of SCY-078 and any future product candidates we may seek to develop, which may adversely affect our results of operations.

Risks Relating to Our Contract Research and Development Services

We are substantially dependent on our agreement with Merial for generation of our revenues, and that agreement expires on December 31, 2014.

We have a research services contract with Merial Limited, or Merial, under which we perform research services for Merial, including the synthesis, purification, and characterization of individual or libraries of compounds, phenotypic screening of compounds, and further testing and optimizing of compounds to support the development of animal health products, which agreement expires on December 31, 2014. Revenues from this contract have accounted for 41% and 44% of our total revenues for the nine months ended September 30, 2013, and year ended December 31, 2012, respectively. If we are not able to extend or replace this contract upon expiration, or if this contract were to terminate prior to December 31, 2014, our ability to generate revenues prior to the commercialization of SCY-078 would be significantly impaired. Merial may also terminate the agreement prior to December 31, 2014 under specified circumstances, including in the event of breach by us of a material obligation if such breach is not remedied after written notice from Merial, or if Merial believes in good faith that we have acted in any way that may subject Merial to liability under anti-corruption laws. During the term and for a period of one year after termination of this agreement for any reason, we cannot provide services to another animal health company using the same intellectual property developed under this agreement, which could also significantly impair our ability to generate revenue from our contract research and development services should this contract terminate.

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We face potential liability and exposure as a result of the performance of our contract research and development services, and if successful claims are brought against us, we may incur substantial liability, which may exceed the revenues we have received for the performance of our contract research and development services.

To date substantially all of our revenue has been generated from the provision of our contract research and development services. In the event that a regulator asserts that we have conducted activities in a non-compliant manner or a customer asserts that we have conducted our contract research and development services negligently, or otherwise asserts that as a result of the performance of our contract research and development services for that client we have somehow harmed their business or the prospects of their product candidates, we could be subject to litigation, which could divert management’s attention from the operation of our business, including the development of SCY-078. Further, if such litigation is successful, or if we determine that we must settle the litigation, we could be forced to pay substantial damages, which could be more than the revenues that we generated from that customer, as the services that we perform are only a small portion of the development efforts of our customers. Even if we are successful in defending any such claims, we could incur substantial legal costs to do so. Further, publicity of any such litigation or claims could hurt the reputation of our ability to perform contract research and development services, which could cause revenue generated from our contract research and development services to decline. Any such litigation against us could result in substantial costs and divert our management’s attention from other business concerns, which could seriously harm our business.

Risks Related to Our Dependence on Third Parties

We are dependent on our existing third-party collaboration with R-Pharm to commercialize SCY-078 in the Russian Federation and certain other countries, and if R-Pharm is not successful in commercializing SCY-078 in those countries, we will lose a significant source of revenue.

We currently have a development license and supply agreement with R-Pharm, CJSC, or R-Pharm, a leading supplier of hospital drugs in Russia, pursuant to which we license to R-Pharm rights to develop and commercialize SCY-078 in the field of human health in Russia and certain smaller non-core markets. R-Pharm will pay us milestone payments upon the achievement of specified milestones, including registration of SCY-078 in a country and upon the achievement of specified levels of sales. In addition, R-Pharm will pay us royalties upon sales of SCY-078 by R-Pharm. We are relying on R-Pharm to commercialize SCY-078 in the countries covered by our agreement with it, and if R-Pharm is not able to commercialize SCY-078 in those countries, or determines not to pursue commercialization of SCY-078 in those countries, we will not receive any milestone or royalty payments under the agreement.

We are dependent on other third-party collaborations to develop and commercialize product candidates we have outlicensed, and if our third-party collaborators are not successful in developing and commercializing product candidates we have outlicensed, we will not receive any revenue from these collaborations.

A significant portion of our strategy is to license to third parties rights to develop and commercialize product candidates we have discovered other than SCY-078, and if these third parties do not perform under our agreements with them, we will not receive any revenue from these collaborations. For example, we currently have a license agreement with Dechra Ltd., or Dechra, pursuant to which we license to Dechra rights to develop and commercialize SCY-641 for use in animal health, and will receive royalties from Dechra on sales of SCY-641. We are relying on Dechra to commercialize SCY-641, and if Dechra is not able to commercialize SCY-641, or determines not to pursue commercialization of SCY-641, we will not receive any royalty payments under the agreement. If our third-party collaborators under this and any future

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agreements we enter into do not perform under these agreements, we will not receive the benefits we expect under these agreements.

We are dependent on our existing third-party collaborations in animal health to fund additional development opportunities and expect to continue to expend resources in our current collaborations, and if these collaborations fail, then we will lose a significant source of revenues.

We provide contract research and development services in the field of animal health which is a source of significant revenues to us. For example, we have an agreement with Merial, pursuant to which we provide contract research and development services that primarily target parasites, which includes the synthesis, purification, and characterization of individual or libraries of compounds, phenotypic screening of compounds, and further testing and optimizing of compounds for the use of commercializing animal health products. If we are not able to continue to enter into and perform under these services agreements, we will lose the ability to generate significant revenues.

We may not be successful in establishing and maintaining development and commercialization collaborations, which could adversely affect our ability to develop and commercialize product candidates.

Developing pharmaceutical products, conducting clinical trials, obtaining regulatory approval, establishing manufacturing capabilities and marketing approved products is expensive. Consequently, we plan to establish collaborations for development and commercialization of product candidates and research programs. For example, we currently have a development license and supply agreement with R-Pharm, pursuant to which we license to R-Pharm rights to develop and commercialize SCY-078 in the field of human health in Russia and certain smaller non-core markets, and if SCY-078 receives marketing approval, we may enter into additional sales and marketing arrangements with third parties for international sales. If we are unable to enter into any of these arrangements on acceptable terms, or at all, we may be unable to market and sell SCY-078 and any future product candidates we may seek to develop in certain markets. We expect to face competition in seeking appropriate collaborators. Moreover, collaboration arrangements are complex and time consuming to negotiate, document and implement and they may require substantial resources to maintain. We may not be successful in our efforts to establish and implement collaborations or other alternative arrangements for the development of product candidates. When we partner with a third party for development and commercialization of a product candidate, we can expect to relinquish to the third party some or all of the control over the future success of that product candidate. Our collaboration partner may not devote sufficient resources to the commercialization of product candidates or may otherwise fail in their commercialization. The terms of any collaboration or other arrangement that we establish may not be favorable to us. In addition, any collaboration that we enter into may be unsuccessful in the development and commercialization of product candidates. In some cases, we may be responsible for continuing preclinical and initial clinical development of a partnered product candidate or research program, and the payment we receive from our collaboration partner may be insufficient to cover the cost of this development. If we are unable to reach agreements with suitable collaborators for product candidates, we could face increased costs, we may be forced to limit the number of product candidates we can commercially develop or the territories in which we commercialize them and we might fail to commercialize products or programs for which a suitable collaborator cannot be found. If we fail to achieve successful collaborations, our operating results and financial condition will be materially and adversely affected.

We depend on third-party contractors for a substantial portion of our drug development activities and may not be able to control their work as effectively as if we performed these functions ourselves.

We outsource, and intend to continue to outsource, substantial portions of our drug development activities to third-party service providers, including manufacturing and the conduct of our clinical trials and various

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preclinical studies. Our agreements with third-party service providers and CROs are and will be on a study-by-study basis and typically short-term. In all cases, we expect to be able to terminate the agreements with notice and be responsible for the supplier’s previously incurred costs.

Because we rely on third parties, our internal capacity to perform these functions is limited. Outsourcing these functions involves risk that third parties may not perform to our standards, may not produce results in a timely manner or may fail to perform at all. Even if we outsource activities, in most cases regulators will hold us responsible for the compliance of the activities performed, and hold us responsible for oversight and monitoring of the activities. In addition, the use of third-party service providers requires us to disclose our proprietary information to these parties, which could increase the risk that this information will be misappropriated. There is a limited number of third-party service providers that have the expertise required to achieve our business objectives. Identifying, qualifying and managing performance of third-party service providers can be difficult and time consuming and could cause delays in our development programs. We currently have a small number of employees devoted to clinical development activities, which limits the internal resources we have available to identify and monitor our third-party providers. To the extent we are unable to identify, retain and successfully manage the performance of third-party service providers in the future, our business may be adversely affected.

We have no experience manufacturing product candidates on a large clinical or commercial scale. As a result, we are and will be dependent on third parties for the manufacture of SCY-078 and any future product candidates we may seek to develop, and if we experience problems with any of these third parties, the commercial manufacturing of SCY-078 and any future product candidates we may seek to develop could be delayed.

We have a small number of personnel with experience in drug product manufacturing. If SCY-078 is approved, the inability to manufacture sufficient commercial supplies of the drug product could adversely affect product commercialization. We do not currently have any agreements with third-party manufacturers for the long-term commercial supply of our product candidates, including SCY-078. We may encounter technical difficulties or delays in the transfer of SCY-078 manufacturing on a commercial scale to a third-party manufacturer, or may be unable to enter into agreements for commercial supply with third-party manufacturers, or may be unable to do so on acceptable terms.

We may not be able to establish additional sources of supply for SCY-078 and any future product candidates we may seek to develop. These suppliers are subject to regulatory requirements covering manufacturing, testing, quality control and record keeping relating to product candidates and are also subject to ongoing inspections by the regulatory agencies. Failure by any of our suppliers to comply with applicable regulations may result in long delays and interruptions to our product candidate supply while we seek to secure another supplier that meets all regulatory requirements.

Reliance on third-party manufacturers entails risks to which we would not be subject if we manufactured product candidates ourselves, including:

Any of these factors could result in delays or higher costs in connection with our clinical trials, regulatory submissions, required approvals or commercialization of SCY-078 and any future product candidates we may seek to develop.

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If we fail to establish or lose our relationships with CROs, our drug development efforts could be delayed.

We are substantially dependent on third-party vendors and CROs for preclinical studies and clinical trials related to our drug discovery and development efforts. If we fail to establish or lose our relationship with any one or more of these providers, we could experience a significant delay in both identifying another comparable provider and then contracting for its services, which could adversely affect our development efforts. We may be unable to retain an alternative provider on reasonable terms, or at all. Even if we locate an alternative provider, it is likely that this provider will need additional time to respond to our needs and may not provide the same type or level of services as the original provider. In addition, any contract research organization that we retain will be subject to the FDA’s regulatory requirements and similar foreign standards and we do not have control over compliance with these regulations by these providers. Consequently, if these practices and standards are not adhered to by these providers, the development and commercialization of SCY-078 and any future product candidates we may seek to develop could be delayed, which could severely harm our business and financial condition.

Risks Relating to Our Intellectual Property

We are dependent on Merck for the establishment of our intellectual property rights related to SCY-078, and if Merck has not established our intellectual property rights with sufficient scope to protect SCY-078, we may have limited or no ability to assert exclusive rights to SCY-078.

Under our agreement with Merck, Merck was responsible for establishing the intellectual property rights to SCY-078. As we were not responsible for the establishment of our intellectual property rights to SCY-078, we have less visibility into the strength of our intellectual property rights to SCY-078 than if we had been responsible for the establishment of these rights. If Merck did not establish those rights so they are of sufficient scope to protect SCY-078, then we may not be able to prevent others from using or commercializing SCY-078, and others may be able to assert intellectual property rights in SCY-078 and prevent us from further pursuing the development and commercialization of SCY-078.

It is difficult and costly to protect our proprietary rights, and we may not be able to ensure their protection.

Our commercial success will depend in part on obtaining and maintaining patent protection and trade secret protection of SCY-078 and any future product candidates we may seek to develop and the methods used to manufacture them, as well as successfully defending these patents against third-party challenges. Our ability to stop third parties from making, using, selling, offering to sell or importing SCY-078 and any future product candidates we may seek to develop is dependent upon the extent to which we have rights under valid and enforceable patents or trade secrets that cover these activities.

The patent positions of pharmaceutical companies can be highly uncertain and involve complex legal and factual questions for which important legal principles remain unresolved. No absolute policy regarding the breadth of claims allowed in pharmaceutical patents has emerged to date in the United States or in many foreign jurisdictions. Changes in either the patent laws or in interpretations of patent laws in the United States and foreign jurisdictions may diminish the value of our intellectual property. Accordingly, we cannot predict the breadth of claims that may be enforced in the patents that we currently own or that may be issued from the applications we have filed or may file in the future or that we have licensed or may license from third parties, including Merck for SCY-078. Further, if any patents we obtain or license are deemed invalid and unenforceable, it could impact our ability to commercialize or license our technology.

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The degree of future protection for our proprietary rights is uncertain because legal means afford only limited protection and may not adequately protect our rights or permit us to gain or keep our competitive advantage. For example:

Due to the patent laws of a country, or the decisions of a patent examiner in a country, or our own filing strategies, we may not obtain patent coverage for all of the product candidates or methods involving these candidates in the parent patent application. We plan to pursue divisional patent applications and/or continuation patent applications in the United States and many other countries to obtain claim coverage for inventions that were disclosed but not claimed in the parent patent application, but may not succeed in these efforts.

Composition of matter patents on the active pharmaceutical ingredient are generally considered to be the strongest form of intellectual property protection for pharmaceutical products, as such patents provide protection without regard to any method of use. We cannot be certain that the claims in our patent applications covering composition-of-matter of our drug candidates will be considered patentable by the U.S. Patent and Trademark Office, or USPTO, courts in the United States or by the patent offices and courts in foreign countries. Method of use patents protect the use of a product for the specified method. This type of patent does not prevent a competitor from making and marketing a product that is identical to our product for an indication that is outside the scope of the patented method. Moreover, even if competitors do not actively promote their product for our targeted indications, physicians may prescribe these products “off-label.” Although off-label prescriptions may infringe or contribute to the infringement of method of use patents, the practice is common and such infringement is difficult to prevent or prosecute. Interference proceedings provoked by third parties or brought by the USPTO may be necessary to determine the priority of inventions with respect to our patents or patent applications or those of our collaborators or licensors. An unfavorable outcome could require us to cease using the related technology or to attempt to license rights to it from the prevailing party. Our business could be harmed if the prevailing party does not offer us a license on commercially reasonable terms. Litigation or interference proceedings may fail and, even if successful, may result in substantial costs and distract our management and other employees. We may not be able to prevent, alone or with our licensors, misappropriation of our trade secrets or confidential information, particularly in countries where the laws may not protect those rights as fully as in the United States.

There have been numerous changes to the patent laws and proposed changes to the rules of the USPTO, which may have a significant impact on our ability to protect our technology and enforce our intellectual property rights. For example, in September 2011, President Obama signed the America Invents Act that codifies several significant changes to the U.S. patent laws, including, among other things, changing from a “first to invent” to a “first inventor to file” system, limiting where a patent holder may file a patent suit, requiring the apportionment of patent damages, replacing interference or “first to invent” proceedings with derivation actions and creating a post-grant opposition process to challenge patents after they have been issued. The effects of these changes are currently unclear as the USPTO must still

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implement various regulations, the courts have yet to address any of these provisions and the applicability of the act and new regulations on specific patents discussed herein have not been determined and would need to be reviewed.

Periodic maintenance fees on any issued patent are due to be paid to the USPTO and foreign patent agencies in several stages over the lifetime of the patent. The USPTO and various foreign governmental patent agencies require compliance with a number of procedural, documentary, fee payment and other similar provisions during the patent application process. While an inadvertent lapse can in many cases be cured by payment of a late fee or by other means in accordance with the applicable rules, there are situations in which noncompliance can result in abandonment or lapse of the patent or patent application, resulting in partial or complete loss of patent rights in the relevant jurisdiction. Noncompliance events that could result in abandonment or lapse of a patent or patent application include, but are not limited to, failure to respond to official actions within prescribed time limits, non-payment of fees and failure to properly legalize and submit formal documents. In such an event, our competitors might be able to enter the market, which would have a material adverse effect on our business.

We also may rely on trade secrets to protect our technology, especially where we do not believe patent protection is appropriate or obtainable. However, trade secrets are difficult to protect. Although we use reasonable efforts to protect our trade secrets, our employees, consultants, contractors, outside scientific collaborators and other advisors may unintentionally or willfully disclose our information to competitors. Enforcing a claim that a third party illegally obtained and is using any of our trade secrets is expensive and time consuming, and the outcome is unpredictable. In addition, courts outside the United States are sometimes less willing to protect trade secrets. Moreover, our competitors may independently develop equivalent knowledge, methods and know-how. Our patent applications would not prevent others from discovering and developing new therapies, including therapies for the indications we are targeting. If others seek to develop similar therapies, their research and development efforts may inhibit our ability to conduct research in certain areas and to expand our intellectual property portfolio.

We may incur substantial costs as a result of litigation or other proceedings relating to patent and other intellectual property rights and we may be unable to enforce or protect our rights to, or use, our technology.

If we choose to go to court to stop another party from using the inventions claimed in any patents we obtain, that individual or company has the right to ask the court to rule that such patents are invalid or should not be enforced against that third party. These lawsuits are expensive and would consume time and resources and divert the attention of managerial and scientific personnel even if we were successful in stopping the infringement of such patents. In addition, there is a risk that the court will decide that such patents are not valid and that we do not have the right to stop the other party from using the inventions. There is also the risk that, even if the validity of such patents is upheld, the court will refuse to stop the other party on the grounds that such other party’s activities do not infringe our rights to such patents. In addition, the U.S. Supreme Court has recently modified some tests used by the USPTO in granting patents over the past 20 years, which may decrease the likelihood that we will be able to obtain patents and increase the likelihood of challenge of any patents we obtain or license.

Furthermore, a third party may claim that we or our manufacturing or commercialization partners are using inventions covered by the third party’s patent rights and may go to court to stop us from engaging in our normal operations and activities, including making or selling SCY-078 and any future product candidates we may seek to develop. These lawsuits are costly and could affect our results of operations and divert the attention of managerial and scientific personnel. There is a risk that a court would decide that we or our commercialization partners are infringing the third party’s patents and would order us or our partners to stop the activities covered by the patents. In that event, we or our commercialization partners may not

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have a viable way around the patent and may need to halt commercialization of the relevant product. In addition, there is a risk that a court will order us or our partners to pay the other party damages for having violated the other party’s patents or obtain one or more licenses from third parties, which may be impossible or require substantial time and expense. We cannot predict whether any license would be available at all or whether it would be available on commercially reasonable terms. Furthermore, even in the absence of litigation, we may need to obtain licenses from third parties to advance our research or allow commercialization of our drug candidates, and we have done so from time to time. We may fail to obtain any of these licenses at a reasonable cost or on reasonable terms, if at all. In that event, we would be unable to further develop and commercialize one or more of our drug candidates, which could harm our business significantly. In the future, we may agree to indemnify our commercial partners against certain intellectual property infringement claims brought by third parties.

Because of the substantial amount of discovery required in connection with intellectual property litigation, there is a risk that some of our confidential information could be compromised by disclosure during this type of litigation. In addition, there could be public announcements of the results of hearings, motions or other interim proceedings or developments. If securities analysts or investors perceive these results to be negative, it could have a substantial adverse effect on the price of our common stock.

The pharmaceutical and biotechnology industries have produced a proliferation of patents, and it is not always clear to industry participants, including us, which patents cover various types of products or methods of use. The coverage of patents is subject to interpretation by the courts, and the interpretation is not always uniform. For example, we are aware of the existence of other patents relating to the treatment of Hepatitis C Virus which, if we are determined to infringe on those patents, may limit our ability to fully commercialize SCY-635. If we are sued for patent infringement, we would need to demonstrate that our products or methods either do not infringe the patent claims of the relevant patent or that the patent claims are invalid, and we may not be able to do this. Proving invalidity is difficult. For example, in the United States, proving invalidity requires a showing of clear and convincing evidence to overcome the presumption of validity enjoyed by issued patents.

Because some patent applications in the United States may be maintained in secrecy until the patents are issued, because patent applications in the United States and many foreign jurisdictions are typically not published until eighteen months after filing and because publications in the scientific literature often lag behind actual discoveries, we cannot be certain that others have not filed patent applications for technology covered by our pending applications. Our competitors may have filed, and may in the future file, patent applications covering technology similar to ours. Any such patent application may have priority over our patent applications, which could further require us to obtain or license rights to issued patents covering such technologies. If another party has filed a U.S. patent application on inventions similar to ours, we may have to participate in an interference proceeding declared by the USPTO to determine priority of invention in the United States. The costs of these proceedings could be substantial, and it is possible that such efforts would be unsuccessful.

We have received confidential and proprietary information from collaborators, prospective licensees and other third parties. In addition, we employ individuals who were previously employed at other biotechnology or pharmaceutical companies. We may be subject to claims that we or our employees, consultants or independent contractors have inadvertently or otherwise used or disclosed confidential information of these third parties or our employees’ former employers. Litigation may be necessary to defend against these claims. Even if we are successful in defending against these claims, litigation could result in substantial cost and be a distraction to our management and employees.

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Some of our competitors may be able to sustain the costs of complex patent litigation more effectively than we can because they have substantially greater resources. In addition, any uncertainties resulting from the initiation and continuation of any litigation could have a material adverse effect on our ability to raise the funds necessary to continue our operations.

Risks Related to Employee Matters and Managing Growth

We may not be able to manage our business effectively if we are unable to attract and retain key personnel.

We may not be able to attract or retain qualified management, finance, scientific and clinical personnel in the future due to the intense competition for qualified personnel among biotechnology, pharmaceutical and other businesses, particularly in the Research Triangle Park area in North Carolina, where we have our offices and research facilities. If we are not able to attract and retain necessary personnel to accomplish our business objectives, we may experience constraints that will significantly impede the achievement of our development objectives, our ability to raise additional capital and our ability to implement our business strategy.

We are highly dependent on the development, regulatory, commercialization and business development expertise of our executive officers and key employees, especially our Chief Executive Officer, Yves Ribeill. If we lose one or more of our executive officers or key employees, our ability to implement our business strategy successfully could be seriously harmed.

We may need to expand our operations and increase the size of our company, and we may experience difficulties in managing growth.

As we advance SCY-078 through preclinical studies, clinical trials and commercialization, we will need to increase our product development, scientific, marketing, sales and administrative headcount to manage these efforts. Our management, personnel and systems currently in place may not be adequate to support this future growth. Our need to effectively manage our operations, growth and various projects requires that we:

If we are unable to successfully manage this growth, our business may be adversely affected.

Other Risks Relating to Our Business

We face potential product liability exposure, and if successful claims are brought against us, we may incur substantial liability for a product candidate and may have to limit its commercialization.

The use of product candidates in clinical trials and the sale of any products for which we may obtain marketing approval expose us to the risk of product liability claims. Product liability claims may be brought against us or our partners by participants enrolled in our clinical trials, patients, healthcare providers or others using, administering or selling products. If we cannot successfully defend ourselves against any such claims, we would incur substantial liabilities. Regardless of merit or eventual outcome, product liability claims may result in:

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We have obtained limited product liability insurance coverage for our clinical trials domestically and in selected foreign countries where we are conducting clinical trials. Our coverage is currently limited to $5.0 million per occurrence and $5.0 million in the aggregate per year, as well as additional local country product liability coverage for trials conducted outside of the United States as required by the local country regulations. As such, our insurance coverage may not reimburse us or may not be sufficient to reimburse us for any expenses or losses we may suffer. Moreover, insurance coverage is becoming increasingly expensive and, in the future, we may not be able to maintain insurance coverage at a reasonable cost or in sufficient amounts to protect us against losses due to product liability. We intend to expand our insurance coverage for products to include the sale of commercial products if we obtain marketing approval for product candidates, but we may be unable to obtain commercially reasonable product liability insurance for any products approved for marketing. Large judgments have been awarded in class action lawsuits based on drugs that had unanticipated side effects. A successful product liability claim or series of claims brought against us, particularly if judgments exceed our insurance coverage, could decrease our cash necessary to develop SCY-078 and any future product candidates we may seek to develop and adversely affect our business.

Our operations involve hazardous materials, which could subject us to significant liabilities.

Our research and development processes involve the controlled use of hazardous materials, including chemicals. Our operations produce hazardous waste products. We cannot eliminate the risk of accidental contamination or discharge or injury from these materials. Federal, state and local laws and regulations govern the use, manufacture, storage, handling and disposal of these materials. We could be subject to civil damages in the event of exposure of individuals to hazardous materials. In addition, claimants may sue us for injury or contamination that results from our use of these materials and our liability may exceed our total assets. We have general liability insurance coverage of up to $1.0 million per occurrence, with an annual aggregate limit of $2.0 million, which excludes pollution liability. This coverage may not be adequate to cover all claims related to our biological or hazardous materials. Furthermore, if we were to be held liable for a claim involving our biological or hazardous materials, this liability could exceed our insurance coverage, if any, and our other financial resources. Compliance with environmental and other laws and regulations may be expensive and current or future regulations may impair our research, development or production efforts. In addition, failure to comply with these laws and regulations also may result in substantial fines, penalties or other sanctions.

Our insurance policies are expensive and protect us only from some business risks, which will leave us exposed to significant uninsured liabilities.

We do not carry insurance for all categories of risk that our business may encounter. Some of the policies we currently maintain include general liability, employment practices liability, property, auto, workers’ compensation, products liability and directors’ and officers’ insurance. We do not know, however,

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if we will be able to maintain existing insurance with adequate levels of coverage. Any significant uninsured liability may require us to pay substantial amounts, which would adversely affect our cash position and results of operations.

Our research and development activities could be affected or delayed as a result of possible restrictions on animal testing.

Certain laws and regulations require us to test our product candidates on animals before initiating clinical trials involving humans. Animal testing activities have been the subject of controversy and adverse publicity. Animal rights groups and other organizations and individuals have attempted to stop animal testing activities by pressing for legislation and regulation in these areas and by disrupting these activities through protests and other means. To the extent the activities of these groups are successful, our research and development activities may be interrupted, delayed or become more expensive.

Risks Relating to This Offering and Owning Our Common Stock

The market price of our common stock may be highly volatile, and you may not be able to resell your shares at or above the initial public offering price.

Prior to this offering, there has not been a public market for our common stock. Although we expect that our common stock will be approved for listing on the NASDAQ Global Market, if an active trading market for our common stock does not develop following this offering you may not be able to sell your shares quickly or above the initial public offering price. The initial public offering price for the shares will be determined by negotiations between us and the representative of the underwriters and may not be indicative of prices that will prevail in the trading market, and the value of our common stock may decrease from the initial public offering price.

The trading price of our common stock is likely to be volatile. The following factors, in addition to other factors described in this “Risk Factors” section and elsewhere in this prospectus, may have a significant impact on the market price of our common stock:

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In addition, companies trading in the stock market in general, and the NASDAQ Global Market in particular, have experienced extreme price and volume fluctuations that have often been unrelated or disproportionate to the operating performance of these companies. Broad market and industry factors may negatively affect the market price of our common stock, regardless of our actual operating performance.

Our executive officers, directors and principal stockholders own a significant percentage of our stock and will be able to exert significant control over matters submitted to our stockholders for approval.

As of December 31, 2013, our executive officers, directors and stockholders who own more than 5% of our outstanding common stock, together beneficially own shares representing approximately     % of our common stock and, upon the closing of this offering, that same group will beneficially own approximately     % of our outstanding stock. Therefore, even after this offering, these stockholders will have the ability to influence us through this ownership position. These stockholders may be able to determine all matters requiring stockholder approval. For example, these stockholders, acting together, may be able to control elections of directors, amendments to our organizational documents, or approval of any merger, sale of assets, or other major corporate action. This may prevent or discourage unsolicited acquisition proposals or offers for our common stock that you may believe are in your best interest as one of our stockholders.

We have identified material weaknesses in our internal controls over financial reporting.

Maintaining effective internal controls over financial reporting is necessary for us to produce accurate financial statements on a timely basis. In 2013, we identified material weaknesses in our internal control over financial reporting. Subsequent to the issuance of our 2012 financial statements we determined that a number of items were misstated, as discussed in Note 18 of the notes to our financial statements appearing elsewhere in this prospectus. As a result, previously reported financial information as of and for the years ended December 31, 2012 and 2011, has been restated to correct for these errors. We are currently in the process of remediating these material weaknesses in internal control over financial reporting by, among other things, designing and implementing new procedures and controls. Management continues to devote significant time and attention to remediating these material weaknesses and improving our internal controls, and we expect to continue to incur costs associated with implementing appropriate processes, which could include fees for additional audit and consulting services, which could negatively affect our financial condition and operating results.

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The requirements associated with being a public company will require significant company resources and management attention.

Following this offering, we will become subject to the reporting requirements of the Securities Exchange Act of 1934, as amended, or the Exchange Act, the Sarbanes-Oxley Act of 2002, or the Sarbanes-Oxley Act, the listing requirements of the NASDAQ Global Market and other applicable securities rules and regulations. The Exchange Act requires that we file annual, quarterly and current reports with respect to our business and financial condition and maintain effective disclosure controls and procedures and internal control over financial reporting. In addition, subsequent rules implemented by the SEC and The NASDAQ Stock Market may also impose various additional requirements on public companies. As a result, we will incur additional legal, accounting and other expenses that we did not incur as a nonpublic company, particularly after we are no longer an “emerging growth company” as defined in the JOBS Act. Further, the need to establish the corporate infrastructure demanded of a public company may divert management’s attention from implementing our growth strategy. We have made, and will continue to make, changes to our corporate governance standards, disclosure controls and financial reporting and accounting systems to meet our reporting obligations. However, the measures we take may not be sufficient to satisfy our obligations as a public company, which could subject us to delisting of our common stock, fines, sanctions and other regulatory action and potentially civil litigation.

Section 404(a) of the Sarbanes-Oxley Act requires annual management assessments of the effectiveness of our internal control over financial reporting, starting with the second annual report that we would expect to file with the SEC, and we will be required to disclose material changes made in our internal controls and procedures on a quarterly basis. Company responsibilities required by the Sarbanes-Oxley Act include establishing corporate oversight and adequate internal control over financial reporting and disclosure controls and procedures. Effective internal controls are necessary for us to produce reliable financial reports and are important to help prevent financial fraud. However, our independent registered public accounting firm will not be required to attest to the effectiveness of our internal control over financial reporting pursuant to Section 404(b) of the Sarbanes-Oxley Act until the later of the year following our first annual report required to be filed with the SEC or the date we are no longer an “emerging growth company” as defined in the JOBS Act, because we are taking advantage of the exemptions contained in the JOBS Act.

To build the infrastructure to allow us to assess the effectiveness of our internal control over financial reporting, we will need to hire additional accounting personnel and improve our accounting systems, disclosure policies, procedures and controls, which will be costly and time consuming. If we are unsuccessful in building an appropriate accounting infrastructure, we may not be able to prepare and disclose, in a timely manner, our financial statements and other required disclosures, or comply with existing or new reporting requirements.

If we identify one or more material weaknesses in our internal control over financial reporting, we will be unable to assert that our internal control over financial reporting is effective. We cannot assure you that there will not be material weaknesses in our internal control over financial reporting in the future. Any failure to maintain internal control over financial reporting could severely inhibit our ability to accurately report our financial condition, results of operations or cash flows. If we are unable to conclude that our internal control over financial reporting is effective, or if our independent registered public accounting firm determines we have a material weakness in our internal control over financial reporting, we could lose investor confidence in the accuracy and completeness of our financial reports, the market price of our common stock could decline, and we could be subject to sanctions or investigations by The NASDAQ Stock Market, the SEC or other regulatory authorities. Failure to remedy any material weakness in our internal control over financial reporting, or to implement or maintain other effective control systems required of public companies, could also restrict our future access to the capital markets.

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The recently enacted JOBS Act will allow us to postpone the date by which we must comply with some of the laws and regulations intended to protect investors and to reduce the amount of information we provide in our reports filed with the SEC, which could undermine investor confidence in our company and adversely affect the market price of our common stock.

For so long as we remain an “emerging growth company” as defined in the JOBS Act, we may take advantage of certain exemptions from various requirements that are applicable to public companies that are not “emerging growth companies” including:

We currently intend to take advantage of some of the reduced regulatory and reporting requirements that will be available to us under the JOBS Act so long as we qualify as an “emerging growth company.”

If you purchase shares of our common stock in this offering, you will incur immediate and substantial dilution in the pro forma net tangible book value of your shares.

Investors purchasing common stock in this offering will pay a price per share that substantially exceeds the pro forma net tangible book value per share. As a result, investors purchasing common stock in this offering will incur immediate dilution of $         per share, based on an assumed initial public offering price of $         per share, the midpoint of the price range set forth on the cover page of this prospectus, and our pro forma net tangible book value as of December 31, 2013. Further, based on these assumptions, investors purchasing common stock in this offering will contribute approximately     % of the total amount invested by stockholders since our inception, but will own only approximately     % of the shares of common stock outstanding. For information on how these amounts were calculated, see “Dilution.”

In addition, as of December 31, 2013, options to purchase              shares of our common stock, at a weighted average exercise price at December 31, 2013, of $         per share, were outstanding. The exercise of any of these options would result in additional dilution. As a result of the dilution, investors purchasing stock in this offering may receive significantly less than the purchase price paid in this offering, if anything, in the event of our liquidation.

Sales of a substantial number of shares of our common stock in the public market by our existing stockholders could cause our stock price to fall.

Sales of a substantial number of shares of our common stock in the public market, or the perception that these sales might occur, could depress the market price of our common stock and could impair our

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ability to raise capital through the sale of additional equity securities. We are unable to predict the effect that sales may have on the prevailing market price of our common stock.

All of the shares of common stock sold in this offering will be freely tradable without restrictions or further registration under the Securities Act of 1933, as amended, or the Securities Act, except for any shares held by our affiliates as defined in Rule 144 under the Securities Act or our current stockholders pursuant to lock-up agreements. Substantially all of the remaining          shares of common stock outstanding after this offering, based on                  shares outstanding as of December 31, 2013, will be restricted as a result of securities laws, lock-up agreements or other contractual restrictions that restrict transfers for at least 180 days after the date of this prospectus. RBC Capital Markets, LLC may, in its sole discretion, release all or some portion of the shares subject to lock-up agreements prior to expiration of the lock-up period.

Certain holders of our securities are entitled to rights with respect to the registration of their shares under the Securities Act, subject to the applicable lock-up arrangement described above. Registration of these shares under the Securities Act would result in the shares becoming freely tradable without restriction under the Securities Act. Any sales of securities by these stockholders could have a material adverse effect on the trading price of our common stock.

Future sales and issuances of our common stock or rights to purchase common stock could result in additional dilution of the percentage ownership of our stockholders and could cause our stock price to fall.

We expect that significant additional capital will be needed in the future to continue our planned operations. To the extent we raise additional capital by issuing equity securities, our stockholders may experience substantial dilution. We may sell common stock, convertible securities or other equity securities in one or more transactions at prices and in a manner we determine from time to time. These sales may also result in new investors gaining rights superior to our existing stockholders.

We have broad discretion in the use of the net proceeds from this offering and may not use them effectively.

Our management will have broad discretion in the use of the net proceeds from this offering, including for any of the purposes described in the section titled “Use of Proceeds,” and you will not have the opportunity as part of your investment decision to assess whether the net proceeds are being used appropriately. Because of the number and variability of factors that will determine our use of the net proceeds from this offering, their ultimate use may vary substantially from their currently intended use. The failure of our management to use these funds effectively could have a material adverse effect on our business, cause the market price of our common stock to decline and delay the development of SCY-078 and any future product candidates we may seek to develop. Pending their use, we may invest the net proceeds from this offering in short-term, investment-grade, interest-bearing instruments and U.S. government securities. These investments may not yield a favorable return to our stockholders.

Because we do not intend to declare cash dividends on our shares of common stock in the foreseeable future, stockholders must rely on appreciation of the value of our common stock for any return on their investment.

We currently anticipate that we will retain future earnings for the development, operation and expansion of our business and do not anticipate declaring or paying any cash dividends in the future. As a result, we expect that only appreciation of the price of our common stock, if any, will provide a return to investors in this offering for the foreseeable future. Investors seeking cash dividends should not invest in our common stock.

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If securities or industry analysts do not publish or cease publishing research or reports about us, our business or our market, or if they change their recommendations regarding our common stock adversely, the price of our common stock and trading volume could decline.

The trading market for our common stock will be influenced by the research and reports that securities or industry analysts may publish about us, our business, our market or our competitors. If any of the analysts who may cover us change their recommendation regarding our common stock adversely, or provide more favorable relative recommendations about our competitors, the price of our common stock would likely decline. If any analyst who may cover us were to cease coverage of our company or fail to regularly publish reports on us, we could lose visibility in the financial markets, which in turn could cause the price of our common stock or trading volume to decline.

We may be subject to securities litigation, which is expensive and could divert management attention.

Our share price may be volatile, and in the past, companies that have experienced volatility in the market price of their stock have been subject to securities class action litigation. We may be the target of this type of litigation in the future. Litigation of this type could result in substantial costs and diversion of management’s attention and resources, which could seriously harm our business. Any adverse determination in litigation could also subject us to significant liabilities.

Anti-takeover provisions in our charter documents and under Delaware law could make an acquisition of us, which may be beneficial to our stockholders, more difficult and may prevent attempts by our stockholders to replace or remove our current management.

Provisions in our amended and restated certificate of incorporation and our bylaws may delay or prevent an acquisition of us, including the ability of our board of directors establish new series of preferred stock and issue shares of these new series, which could be used by our board of directors to oppose a hostile takeover attempt, which some stockholders may believe would be in the best interests of stockholders. In addition, these provisions may frustrate or prevent any attempts by our stockholders to replace or remove our current management by making it more difficult for stockholders to replace members of our board of directors, which is responsible for appointing the members of our management, including the elimination of cumulative voting, inability of our stockholders to call special meetings or take action by written consent, ability of our board of directors to fill board vacancies, and ability of our board of directors to determine the size of the board of directors. In addition, we are subject to Section 203 of the Delaware General Corporation Law, which generally prohibits stockholders owning in excess of 15% of our outstanding voting stock from merging or combining with us. Finally, our charter documents establish advance notice requirements for nominations for election to our board of directors and for proposing matters that can be acted upon at stockholder meetings. Although we believe these provisions together provide for an opportunity to receive higher bids by requiring potential acquirers to negotiate with our board of directors, they would apply even if the offer may be considered beneficial by some stockholders.

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CAUTIONARY STATEMENT CONCERNING FORWARD-LOOKING STATEMENTS

This prospectus, including the sections titled “Prospectus Summary,” “Risk Factors,” “Use of Proceeds,” “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” “Market, Industry and Other Data,” “Business” and “Shares Eligible for Future Sale,” contains forward-looking statements. In some cases you can identify these statements by forward-looking words, such as “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “goal,” “intend,” “may,” “plan,” “potential,” “seek,” “will,” “would,” or the negative or plural of these words or similar expressions. These forward-looking statements include, but are not limited to, statements concerning the following:

These forward-looking statements are subject to a number of risks, uncertainties and assumptions, including those described in “Risk Factors.” Moreover, we operate in a very competitive and rapidly changing environment. New risks emerge from time to time. It is not possible for our management to predict all risks, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements we may make. In light of these risks, uncertainties and assumptions, the forward-looking events and circumstances discussed in this prospectus may not occur and actual results could differ materially and adversely from those anticipated or implied in the forward-looking statements.

You should not rely upon forward-looking statements as predictions of future events. Although we believe that the expectations reflected in the forward-looking statements are reasonable, we cannot guarantee that the future results, levels of activity, performance or events and circumstances reflected in the forward-looking statements will be achieved or occur. Moreover, except as required by law, we undertake no obligation to update publicly any forward-looking statements for any reason after the date of this prospectus to conform these statements to actual results or to changes in our expectations.

You should read this prospectus, and the documents that we reference in this prospectus and have filed with the Securities and Exchange Commission as exhibits to the registration statement of which this

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prospectus is a part, with the understanding that our actual future results, levels of activity, performance and events and circumstances may be materially different from what we expect.

MARKET, INDUSTRY AND OTHER DATA

We obtained the industry, market and other data throughout this prospectus from our own internal estimates and research, as well as from industry publications and research, surveys and studies conducted by third parties. Industry publications, studies and surveys generally state that they have been obtained from sources believed to be reliable, although they do not guarantee the accuracy or completeness of such information. While we believe that each of these studies and publications is reliable, we have not independently verified market and industry data from third-party sources. While we believe our internal company research is reliable and the definitions of our market and industry are appropriate, neither this research nor these definitions have been verified by any independent source.

Information that is based on estimates, forecasts, projections, market research or similar methodologies is inherently subject to uncertainties and actual events or circumstances may differ materially from events and circumstances that are assumed in this information. In some cases, we do not expressly refer to the sources from which this data is derived. In that regard, when we refer to one or more sources of this type of data in any paragraph, you should assume that other data of this type appearing in the same paragraph is derived from the same sources, unless otherwise expressly stated or the context otherwise requires.

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USE OF PROCEEDS

We estimate that the net proceeds from our issuance and sale of             shares of our common stock in this offering will be approximately $         million, or approximately $         million if the underwriters exercise their over-allotment option in full, assuming an initial public offering price of $         per share, which is the midpoint of the price range set forth on the cover page of this prospectus, after deducting underwriting discounts and commissions and estimated offering expenses payable by us.

A $1.00 increase (decrease) in the assumed initial public offering price of $         per share would increase (decrease) the net proceeds from this offering by approximately $         million, assuming that the number of shares we are offering, as set forth on the cover page of this prospectus, remains the same, after deducting underwriting discounts and commissions and estimated offering expenses payable by us. We may also increase or decrease the number of shares we are offering. Each increase (decrease) of             shares in the number of shares we are offering would increase (decrease) the net proceeds to us from this offering by approximately $         million, assuming that the assumed initial public offering price remains the same, and after deducting underwriting discounts and commissions and estimated offering expenses payable by us.

As of December 31, 2013, we had cash and cash equivalents of approximately $         million. We currently estimate that we will use the net proceeds from this offering, together with our cash and cash equivalents as follows:

This expected use of the net proceeds from this offering and our existing cash and cash equivalents represents our intentions based upon our current plans and business conditions. The amounts and timing of our actual expenditures may vary significantly depending on numerous factors, including the progress of our development and commercialization efforts and the status of and results from clinical studies, as well as any collaborations that we may enter into with third parties and any unforeseen cash needs. As a result, our management will retain broad discretion over the allocation of the net proceeds from this offering.

Pending our use of the net proceeds from this offering, we intend to invest the net proceeds in a variety of capital preservation investments, including short-term, investment grade, interest bearing instruments and U.S. government securities.

DIVIDEND POLICY

We have never declared or paid, and do not anticipate declaring, or paying in the foreseeable future, any cash dividends on our capital stock. Future determination as to the declaration and payment of dividends, if any, will be at the discretion of our board of directors and will depend on then existing conditions, including our operating results, financial conditions, contractual restrictions, capital requirements, business prospects and other factors our board of directors may deem relevant.

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DILUTION

Dilution is the amount by which the offering price paid by the purchasers of the shares of common stock sold in this offering exceeds the pro forma as adjusted net tangible book value per share of our common stock after this offering. The pro forma net tangible book value of our common stock as of December 31, 2013, was $         million, or $         per share. Pro forma net tangible book value per share represents our total tangible assets less our total liabilities, divided by the number of outstanding shares of common stock, after giving effect to the pro forma adjustments referenced under “Capitalization.”

After giving effect to (a) the pro forma adjustments referenced under “Capitalization” and (b) receipt of the net proceeds from our sale of             shares of common stock at an assumed initial public offering price of $         per share, the midpoint of the price range set forth on the cover page of this prospectus, after deducting underwriting discounts and commissions and estimated offering expenses payable by us, our pro forma as adjusted net tangible book value as of December 31, 2013, would have been approximately $         million, or $         per share. This represents an immediate increase in pro forma net tangible book value of $         per share to our existing stockholders and an immediate dilution of $         per share to investors purchasing common stock in this offering.

The following table illustrates this dilution on a per share basis to new investors:

If the underwriters’ over-allotment option to purchase additional shares in this offering is exercised in full, the pro forma net tangible book value, as adjusted to give effect to this offering, would be $         per share and the dilution to new investors would be $         per share.

Each $1.00 increase (decrease) in the assumed initial public offering price of $         per share would increase (decrease) the pro forma net tangible book value, as adjusted to give effect to this offering but assuming no exercise of the underwriters’ over-allotment option, by $         per share and the dilution to new investors by $         per share, assuming the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same, after deducting underwriting discounts and commissions and estimated offering expenses payable by us.

We may also increase or decrease the number of shares we are offering. An increase of             shares in the number of shares offered by us would increase our pro forma as adjusted net tangible book value by approximately $         million, or $         per share, and the pro forma dilution per share to investors in this offering by $         per share, assuming that the assumed initial public offering price remains the same, and after deducting underwriting discounts and commissions and estimated offering expenses payable by us. Similarly, a decrease of             shares in the number of shares offered by us would decrease our pro forma as adjusted net tangible book value by approximately $         million, or $         per share, and the pro forma dilution per share to investors in this offering by $         per share, assuming that the assumed initial public offering price remains the same, and after deducting underwriting discounts and commissions and estimated offering expenses payable by us. The pro forma information discussed above is illustrative only and will change based on the actual initial public offering price and other terms of this offering determined at pricing.

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The table below summarizes as of December 31, 2013, on a pro forma as adjusted basis described above, the number of shares of our common stock, the total consideration, and the average price per share (a) paid to us by our existing stockholders and (b) to be paid by new investors purchasing our common stock in this offering at an assumed initial public offering price of $         per share, the midpoint of the price range set forth on the cover page of this prospectus, before deducting underwriting discounts and commissions and estimated offering expenses payable by us.

A $1.00 increase (decrease) in the assumed initial public offering price of $         per share would increase (decrease) total consideration paid by new investors by $         and increase (decrease) the percent of total consideration paid by new investors by     %, assuming the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same. We may also increase or decrease the number of shares we are offering.

If the underwriters’ over-allotment option to purchase additional shares in this offering is exercised in full, the percentage of shares of our common stock held by existing stockholders will be reduced to     % of the total number of shares of our common stock outstanding after this offering, and the number of shares held by new investors will increase to             shares, or     % of the total number of shares of our common stock outstanding after this offering.

The number of shares of our common stock reflected in the discussion and tables above is based on              shares of our common stock outstanding as of December 31, 2013 (including convertible preferred stock on an as-converted basis), and excludes the following:

To the extent that any outstanding options or warrants are exercised, new options are issued under our stock-based compensation plans or we issue additional shares of common stock in the future, there will be further dilution to investors participating in this offering.

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CAPITALIZATION

The following table sets forth our cash and cash equivalents and capitalization as of December 31, 2013:

You should read this table together with the sections in this prospectus titled “Selected Financial Data,” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and our financial statements and related notes included elsewhere in this prospectus.

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The outstanding share information in the table above is based on              shares of our common stock outstanding as of December 31, 2013 (including convertible preferred stock on an as-converted basis), and excludes the following:

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SELECTED FINANCIAL DATA

You should read the following selected financial data together with the section of this prospectus titled “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and our financial statements and the related notes included elsewhere in this prospectus. The statement of operations data for the years ended December 31, 2012 and 2011, and the balance sheet data as of December 31, 2012 and 2011, are derived from the audited financial statements that are included elsewhere in this prospectus. The statement of operations data for the nine months ended September 30, 2013 and 2012, and the balance sheet data as of September 30, 2013, are derived from our unaudited financial statements included elsewhere in this prospectus. We have included, in our opinion, all adjustments, consisting only of normal recurring adjustments, that we consider necessary for a fair presentation of the financial information set forth in those financial statements. Our historical results are not necessarily indicative of the results to be expected in the future, and our interim unaudited results are not necessarily indicative of the results to be expected for the full year or any other period.