1. Nature of the Business

Merrimack Pharmaceuticals, Inc. (the “Company”) is a clinical stage biopharmaceutical company based in Cambridge, Massachusetts that is outthinking cancer by targeting biomarker-defined cancers. The Company’s vision is to ensure that cancer patients and their families live fulfilling lives. The Company’s mission is to transform cancer care through the smart design and development of targeted solutions based on a deep understanding of cancer pathways and biological markers. All of the Company’s development programs, including four clinical trials and six candidates in preclinical development, fit into the Company’s strategy of (1) understanding the biological problems it is trying to solve, (2) designing specific solutions against the problems it is trying to solve and (3) developing those solutions for biomarker-selected patients. This three-pronged strategy seeks to ensure optimal patient outcomes.

The Company owns worldwide development and commercial rights to all of its clinical and preclinical programs. The Company’s most advanced assets and a description of the status of each asset are as follows:

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MM-121 (seribantumab): MM-121 is a fully human monoclonal antibody that binds to the ErbB3 (HER3) receptor and targets heregulin positive cancers. There are two active development programs for MM-121, each in a Phase 2 clinical trial. The Company is conducting the global, open-label, biomarker-selected, Phase 2 randomized SHERLOC clinical trial evaluating MM-121 in combination with docetaxel in patients with heregulin positive non-small cell lung cancer. The Company is also conducting the global, double-blinded, placebo-controlled, biomarker-selected, Phase 2 randomized SHERBOC clinical trial evaluating MM-121 in combination with fulvestrant in patients with heregulin positive, hormone receptor positive, ErbB2 (HER2) negative, metastatic breast cancer;

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MM-141 (istiratumab): MM-141 is a fully human tetravalent bispecific antibody designed to block tumor survival signals by targeting receptor complexes containing the insulin-like growth factor 1 (“IGF-1”), receptor and ErbB3 (HER3) cell surface receptor. The Company is conducting and has completed enrollment of the global, double-blinded, placebo-controlled, Phase 2 randomized CARRIE clinical trial evaluating MM-141 in combination with nab-paclitaxel and gemcitabine in patients with previously untreated metastatic pancreatic cancer with high serum levels of free IGF-1; and

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MM-310: MM-310 is an antibody-directed nanotherapeutic that targets the ephrin receptor A2 (“EphA2”) receptor and contains a novel prodrug of the highly potent chemotherapy docetaxel. The EphA2 receptor is highly expressed in most solid tumor types, such as prostate, ovarian, bladder, gastric, pancreatic and lung cancers. The Company is conducting a Phase 1 clinical trial to evaluate safety and preliminary activity of MM-310 in patients with solid tumors and to identify the maximum tolerated dose.

The Company is subject to risks and uncertainties common to companies in the biopharmaceutical industry, including, among other things, its ability to secure additional capital to fund operations, success of clinical trials, development by competitors of new technological innovations, dependence on collaborative arrangements, protection of proprietary technology, compliance with government regulations and dependence on key personnel. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts require significant amounts of capital, adequate personnel, infrastructure and extensive compliance reporting capabilities.

The Company’s product candidates are in development, and none are approved for any indication by the U.S. Food and Drug Administration (“FDA”) or any other regulatory agency. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s intellectual property will be obtained or maintained, that any products developed will obtain necessary government regulatory approval or that any approved products will be commercially viable. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will generate significant revenue from product sales. The Company operates in an environment of rapid change in technology and substantial competition from pharmaceutical and biotechnology companies, among others. In addition, the Company is dependent upon the services of its employees and consultants.

In accordance with Accounting Standards Codification (“ASC”) 205-40, Going Concern, the Company has evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the condensed consolidated financial statements are issued. As of March 31, 2018, the Company had an accumulated deficit of $500.6 million. During the three months ended March 31, 2018, the Company incurred a net loss from continuing operations of $17.8 million and used $17.3 million of cash in continuing operations for operating activities. The Company expects to continue to generate operating losses in the foreseeable future. The Company expects that its cash and cash equivalents and marketable securities of $76.3 million at March 31, 2018 will be sufficient to fund its operating expenses and capital expenditure requirements for at least the next 12 months from the date that the condensed consolidated financial statements are issued.

The Company will ultimately need to seek additional funding through equity offerings, debt financings, collaborations, licensing arrangements and other marketing and distribution arrangements, partnerships, joint ventures, combinations or divestitures of one or more of its businesses. The Company may not be able to obtain financing on acceptable terms, or at all, and the Company may not be able to enter into collaborative arrangements or divest its assets. The terms of any financing may adversely affect the holdings or the rights of the Company’s stockholders. Arrangements with collaborators or others may require the Company to relinquish rights to certain of its technologies or product candidates. If the Company is unable to obtain funding, the Company could be forced to delay, reduce or eliminate its research and development programs or commercialization efforts, which could adversely affect its business prospects.