Use these links to rapidly review the document TABLE OF CONTENTS Verastem, Inc. (A development stage company) Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K (Mark One) ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2013 or o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 001-35403 Verastem, Inc. (Exact name of registrant as specified in its charter) Delaware 27-3269467 (State or other jurisdiction of (I.R.S. Employer incorporation or organization) Identification No.) 215 First Street, Suite 440 Cambridge, Massachusetts (Address of principal executive 02142 offices) (Zip Code) Registrant's telephone number, including area code: (617) 252-9300 Securities registered pursuant to Section 12(b) of the Act: Name of each exchange on which Title of each class registered Common Stock, $0.0001 par value NASDAQ Global Market Securities registered pursuant to Section 12(g) of the Act: None Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. o Yes No Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. o Yes No Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes o No Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Website, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files). Yes o No Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of registrant's knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K. 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 definitions of "large accelerated filer," "accelerated filer" and "smaller reporting company" in Rule 12b-2 of the Exchange Act. (Check one): Large accelerated filer o Accelerated filer Non-accelerated filer o Smaller reporting company o (Do not check if a smaller reporting company) Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). o Yes No Aggregate market value of the voting and non-voting common equity held by non-affiliates of the registrant as of June 28, 2013 was $203,917,000. The number of shares outstanding of the registrant's common stock as of February 28, 2014 was 25,822,939. DOCUMENTS INCORPORATED BY REFERENCE Portions of our definitive proxy statement to be delivered to stockholders in connection with the 2014 Annual Meeting of Stockholders are incorporated by reference into Part III of this Annual Report on Form 10-K. Table of Contents TABLE OF CONTENTS PART I Item 1. Business 4 Item 1A. Risk Factors 46 Item 1B. Unresolved Staff Comments 73 Item 2. Properties 73 Item 3. Legal Proceedings 73 Item 4. Mine Safety Disclosures 73 PART II Item 5. Market for Registrant's Common Equity, Related Stockholder Matters and Issuers Purchases of Equity Securities 74 Item 6. Selected Financial Data 76 Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations 77 Item 7A. Quantitative and Qualitative Disclosures About Market Risk 87 Item 8. Financial Statements and Supplementary Data 88 Item 9. Changes in and Disagreements With Accountants on Accounting and Financial Disclosure 88 Item 9A. Controls and Procedures 88 Item 9B. Other Information 89 PART III Item 10. Directors, Executive Officers and Corporate Governance 90 Item 11. Executive Compensation 90 Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters 90 Item 13. Certain Relationships and Related Transactions, and Director Independence 90 Item 14. Principal Accountant Fees and Services 90 PART IV Item 15. Exhibits and Financial Statement Schedules 91 SIGNATURES 92 2 Table of Contents FORWARD-LOOKING STATEMENTS This Annual Report on Form 10-K contains forward-looking statements that involve substantial risks and uncertainties. All statements, other than statements related to present facts or current conditions or of historical facts, contained in this Annual Report on Form 10-K, including statements regarding our strategy, future operations, future financial position, future revenues, projected costs, prospects, plans and objectives of management, are forward looking statements. Such statements relate to, among other things, the development of our compounds and diagnostics programs, the timeline for clinical development and regulatory approval of our compounds, the expected timing for the reporting of data from ongoing trials, the structure of our planned or pending clinical trials and our ability to fund operations. The words "anticipate," "believe," "estimate," "expect," "intend," "may," "plan," "predict," "project," "target," "potential," "will," "would," "could," "should," "continue" and similar expressions are intended to identify forward- looking statements, although not all forward-looking statements contain these identifying words. Forward-looking statements are not guarantees of future performance and our actual results could differ materially from the results discussed in the forward-looking statements. Factors that could cause actual results to differ materially from those in the forward-looking statements include, but are not limited to, our ability to raise additional capital to support our clinical development programs and other operations, our ability to develop products of commercial value and to identify, discover and obtain rights to additional potential product candidates, our ability to protect and maintain our intellectual property and the ability of our licensors to obtain and maintain patent protection for the technology or products that we license from them, the outcome of research and development activities, the fact that the preclinical and clinical testing of our compounds and preliminary data from clinical trials may not be predictive of the success of ongoing or later clinical trials, that data may not be available when we expect it to be, our reliance on third-parties, competitive developments, the effect of current and future legislation and regulation and regulatory actions, as well as other risks described in this Annual Report on Form 10-K and other filings with the Securities and Exchange Commission, or SEC. As a result of these and other factors, we may not actually achieve the plans, intentions or expectations disclosed in our forward-looking statements, and you should not place undue reliance on our forward-looking statements. Our forward-looking statements do not reflect the potential impact of any future acquisitions, mergers, dispositions, joint ventures or investments we may make. We do not assume any obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law. 3 Table of Contents PART I Item 1. Business OVERVIEW We are a biopharmaceutical company focused on discovering and developing drugs to treat cancer by the targeted killing of cancer stem cells. A cancer stem cell is a particularly aggressive type of tumor cell, resistant to conventional cancer therapy, that we believe is an underlying cause of tumors, their recurrence and metastasis. We have proprietary technology to create a stable population of cancer stem cells that we use to screen for and identify small molecule compounds that target cancer stem cells. Our most advanced programs target the Focal Adhesion Kinase, or FAK, and the PI3K/mTOR signaling pathways. Our lead FAK inhibitor, VS-6063, has been assigned defactinib as the United States Adopted Name (USAN). We have received orphan drug designation for the use of VS-6063 in mesothelioma in the European Union and in the United States. VS-6063 is currently in a registration-directed trial (COMMAND) in patients with mesothelioma, a Phase 1b trial in combination with weekly paclitaxel for patients with ovarian cancer, a Phase 2 study in patients with non-small cell lung cancer and a Phase 1 trial in Japan in patients with solid tumors. In addition to VS-6063, both our FAK inhibitor VS-4718 and our dual mTORC1/2 and PI3K inhibitor VS-5584 are in Phase 1 clinical trials in patients with advanced cancers. Cancer is a group of diseases characterized by uncontrolled growth and spread of abnormal cells. The American Cancer Society estimated that in the United States in 2013, approximately 1.7 million new cases of cancer would be diagnosed and nearly 600,000 people would die from the disease. Current treatments for cancer include surgery, radiation therapy, chemotherapy, hormone therapy and targeted therapy. According to estimates by the National Institutes of Health, in the United States in 2010, the direct medical costs of cancer of all types exceeded $100 billion. IMS Health estimates that in the United States in 2010, approximately $22 billion was spent on drugs to treat cancer, representing the largest class of drug spending in the United States. Despite years of intensive research and clinical use, current treatments often fail to cure cancer.