Nature of the Business	3 Months Ended
Mar. 31, 2023
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of the Business	1. Nature of the Business Merrimack Pharmaceuticals, Inc. (the “Company”) is a biopharmaceutical company based in Cambridge, Massachusetts that is entitled to receive up to $450.0 million in contingent milestone payments related to its sale of ONIVYDE® and MM-436 (the “Commercial Business”) to Ipsen S.A. (“Ipsen”) in April 2017 (the “Ipsen Sale”). The Company does not have any ongoing research or development activities. The Company does not have any employees and instead uses external consultants for the operation of the Company. The $450.0 million in contingent milestone payments resulting from the Ipsen Sale consist of: • $225.0 million upon approval by the U.S. Food and Drug Administration (“FDA”) of ONIVYDE® for the first-line treatment of metastatic adenocarcinoma of the pancreas (“mPDAC”), subject to certain conditions; • $150.0 million upon approval by the FDA of ONIVYDE® for the treatment of small-cell lung cancer after failure of first-line chemotherapy; and • $75.0 million upon approval by the FDA of ONIVYDE® for an additional indication unrelated to those described above. In February 2023, Ipsen provided guidance to investors that it intends to file a supplemental New Drug Application with the U.S. Food and Drug Administration during the first half of 2023 following the Fast Track Designation granted in 2020 for the use of Onivyde in combination with oxaliplatin plus 5-fluorouracil/leucovorin for the treatment of patients with previously untreated mPDAC. On May 30, 2019, the Company announced the completion of its review of strategic alternatives, following which the Company’s board of directors (the “Board”) implemented a series of measures designed to extend the Company’s cash runway and preserve its ability to capture the potential milestone payments resulting from the Ipsen Sale. In connection with that announcement, the Company discontinued the discovery efforts on its remaining preclinical programs: MM-401, an agonistic antibody targeting a novel immuno-oncology target, TNFR2; and MM-201, a highly stabilized agonist-Fc fusion protein targeting death receptors 4 and 5. The Company’s termination of its executive management team and all other employees was substantially completed by June 28, 2019 and fully completed by July 12, 2019. As of July 12, 2019, the Company no longer had any employees. The Company has engaged external consultants to run the day-to-day operations of the Company. The Company has also entered into consulting agreements with certain former members of its executive management team who are supporting the Company’s relationship with current partners, assisting with the potential sale of remaining preclinical and clinical assets, and assisting with certain legal and regulatory matters and the continued wind-down of operations. On July 12, 2019, the Company completed the sale to Elevation Oncology, Inc. (formerly known as 14ner Oncology, Inc.) (“Elevation”) of its anti-HER3 antibody programs, MM-121 (seribantumab) and MM-111 (the “Elevation Sale”). In connection with the Elevation Sale, the Company received an upfront cash payment of $3.5 million. The Company is also eligible to receive up to $54.5 million in additional potential development, regulatory approval and commercial-based milestone payments, consisting of: • $3.0 million for achievement of the primary endpoint in the first registrational clinical study of either MM-121 or MM-111; • Up to $16.5 million in total payments for the achievement of various regulatory approval and reimbursement-based milestones in the United States, Europe and Japan; and • Up to $35.0 million in total payments for achieving various cumulative worldwide net sales targets between $100.0 million and $300.0 million for MM-121 and MM-111. In January 2023, Elevation announced it is pausing further investment in the clinical development of seribantumab and intends to pursue further development only in collaboration with a partner. On March 14, 2023, Elevation Oncology announced that it would be presenting two posters on NRG1 fusions, including updated data from the Phase 2 CRESTONE study evaluating seribantumab in patients with solid tumors harboring NRG1 fusions at the American Association for Cancer Research (AACR) Annual Meeting 2023, held April 14-19, 2023. On September 15, 2021, the Company entered into an Asset Purchase Option Agreement (the "Asset Purchase Option Agreement") with a third party, pursuant to which the third party agreed to obtain an exclusive option, to purchase one of the Company’s preclinical programs with a consideration of $0.5 million. Under the terms of the Asset Purchase Option Agreement, the third party paid to the Company the option fee of $0.1 million. The third party had the right to exercise the option within 24 months from September 15, 2021. The Company recognized a gain of $0.1 million related to the option fee payment for the year ended December 31, 2021. On January 18, 2022, the third party provided written notice to the Company of its intent to exercise such option. On March 1, 2022 the Company and the third party entered into the Asset Purchase Agreement. The consideration of $0.5 million was paid to the Company and a gain of $0.5 million was recognized in March 2022. On January 23, 2023, the Company entered into another Asset Purchase Option Agreement (the “Option Agreement”) with another third party (the “Purchaser”), pursuant to which the Purchaser agreed to obtain an exclusive option (the “Option”) to purchase one of the Company’s preclinical programs with a consideration of $700 thousand. Under the terms of the Option Agreement, the Purchaser paid to the Company the Option fee of $150 thousand and the Company incurred transaction costs of $11 thousand. A net gain of $139 thousand was recognized in January 2023. The Purchaser may exercise the Option prior to July 23, 2023. Our remaining non-commercial assets, including our clinical and preclinical development programs, and all material other clinical and pre-clinical development programs have been sold with the exception of one program under the Option Agreement. 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, development by competitors of new technological innovations, protection of proprietary technology and compliance with government regulations. None of the Company’s product candidates sold to others or retained by the Company are approved for any indication by the FDA or any other regulatory agency. 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 external consultants for the operation of the Company. The Company’s business strategy depends substantially upon its ability to receive future milestone payments from Ipsen. Any failure to achieve such milestones or a perception that the milestones may not be achieved will materially and adversely affect the Company and the value of its common stock. 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, 2023, the Company had an accumulated deficit of $547.9 million. During the three months ended March 31, 2023, the Company incurred net loss of $0.3 million and used $0.4 million of cash in operating activities. The Company expects to continue to generate operating losses for the foreseeable future. The Company expects that its cash and cash equivalents of $19.4 million at March 31, 2023 will allow the Company to continue its operations beyond 2027, which the Company estimates is beyond the latest date that the longest-term potential Ipsen milestone may be achieved. The continued viability of the Company beyond that point is dependent on its ability to raise additional capital to finance its operations or to reduce operating expenses. There can be no assurance that the Company will be able to obtain sufficient capital to cover its costs on acceptable terms, if at all. The Company expects that it would seek to finance any future cash needs through a combination of divestitures of its rights under the Ipsen and Elevation agreements, equity offerings and debt financings. There can be no assurance as to the timing, terms or consummation of any divestiture or financing, and the terms of any such financing may adversely affect the holdings or the rights of the Company’s stockholders or require the Company to relinquish rights to certain of its revenue streams or product candidates.

Merrimack Pharmaceuticals, Inc. (the “Company”) is a biopharmaceutical company based in Cambridge, Massachusetts that is entitled to receive up to $450.0 million in contingent milestone payments related to its sale of ONIVYDE® and MM-436 (the “Commercial Business”) to Ipsen S.A. (“Ipsen”) in April 2017 (the “Ipsen Sale”). The Company does not have any ongoing research or development activities. The Company does not have any employees and instead uses external consultants for the operation of the Company.

The $450.0 million in contingent milestone payments resulting from the Ipsen Sale consist of:

•

$225.0 million upon approval by the U.S. Food and Drug Administration (“FDA”) of ONIVYDE® for the first-line treatment of metastatic adenocarcinoma of the pancreas (“mPDAC”), subject to certain conditions;

•

$150.0 million upon approval by the FDA of ONIVYDE® for the treatment of small-cell lung cancer after failure of first-line chemotherapy; and

•

$75.0 million upon approval by the FDA of ONIVYDE® for an additional indication unrelated to those described above.

In February 2023, Ipsen provided guidance to investors that it intends to file a supplemental New Drug Application with the U.S. Food and Drug Administration during the first half of 2023 following the Fast Track Designation granted in 2020 for the use of Onivyde in combination with oxaliplatin plus 5-fluorouracil/leucovorin for the treatment of patients with previously untreated mPDAC.

On May 30, 2019, the Company announced the completion of its review of strategic alternatives, following which the Company’s board of directors (the “Board”) implemented a series of measures designed to extend the Company’s cash runway and preserve its ability to capture the potential milestone payments resulting from the Ipsen Sale. In connection with that announcement, the Company discontinued the discovery efforts on its remaining preclinical programs: MM-401, an agonistic antibody targeting a novel immuno-oncology target, TNFR2; and MM-201, a highly stabilized agonist-Fc fusion protein targeting death receptors 4 and 5.

The Company’s termination of its executive management team and all other employees was substantially completed by June 28, 2019 and fully completed by July 12, 2019. As of July 12, 2019, the Company no longer had any employees. The Company has engaged external consultants to run the day-to-day operations of the Company. The Company has also entered into consulting agreements with certain former members of its executive management team who are supporting the Company’s relationship with current partners, assisting with the potential sale of remaining preclinical and clinical assets, and assisting with certain legal and regulatory matters and the continued wind-down of operations.

On July 12, 2019, the Company completed the sale to Elevation Oncology, Inc. (formerly known as 14ner Oncology, Inc.) (“Elevation”) of its anti-HER3 antibody programs, MM-121 (seribantumab) and MM-111 (the “Elevation Sale”). In connection with the Elevation Sale, the Company received an upfront cash payment of $3.5 million. The Company is also eligible to receive up to $54.5 million in additional potential development, regulatory approval and commercial-based milestone payments, consisting of:

•

$3.0 million for achievement of the primary endpoint in the first registrational clinical study of either MM-121 or MM-111;

•

Up to $16.5 million in total payments for the achievement of various regulatory approval and reimbursement-based milestones in the United States, Europe and Japan; and

•

Up to $35.0 million in total payments for achieving various cumulative worldwide net sales targets between $100.0 million and $300.0 million for MM-121 and MM-111.

In January 2023, Elevation announced it is pausing further investment in the clinical development of seribantumab and intends to pursue further development only in collaboration with a partner. On March 14, 2023, Elevation Oncology announced that it would be presenting two posters on NRG1 fusions, including updated data from the Phase 2 CRESTONE study evaluating seribantumab in patients with solid tumors harboring NRG1 fusions at the American Association for Cancer Research (AACR) Annual Meeting 2023, held April 14-19, 2023.

On September 15, 2021, the Company entered into an Asset Purchase Option Agreement (the "Asset Purchase Option Agreement") with a third party, pursuant to which the third party agreed to obtain an exclusive option, to purchase one of the Company’s preclinical programs with a consideration of $0.5 million. Under the terms of the Asset Purchase Option Agreement, the third party paid to the Company the option fee of $0.1 million. The third party had the right to exercise the option within 24 months from September 15, 2021. The Company recognized a gain of $0.1 million related to the option fee payment for the year ended

December 31, 2021. On January 18, 2022, the third party provided written notice to the Company of its intent to exercise such option. On March 1, 2022 the Company and the third party entered into the Asset Purchase Agreement. The consideration of $0.5 million was paid to the Company and a gain of $0.5 million was recognized in March 2022.

On January 23, 2023, the Company entered into another Asset Purchase Option Agreement (the “Option Agreement”) with another third party (the “Purchaser”), pursuant to which the Purchaser agreed to obtain an exclusive option (the “Option”) to purchase one of the Company’s preclinical programs with a consideration of $700 thousand. Under the terms of the Option Agreement, the Purchaser paid to the Company the Option fee of $150 thousand and the Company incurred transaction costs of $11 thousand. A net gain of $139 thousand was recognized in January 2023. The Purchaser may exercise the Option prior to July 23, 2023.

Our remaining non-commercial assets, including our clinical and preclinical development programs, and all material other clinical and pre-clinical development programs have been sold with the exception of one program under the Option Agreement.

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, development by competitors of new technological innovations, protection of proprietary technology and compliance with government regulations. None of the Company’s product candidates sold to others or retained by the Company are approved for any indication by the FDA or any other regulatory agency. 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 external consultants for the operation of the Company. The Company’s business strategy depends substantially upon its ability to receive future milestone payments from Ipsen. Any failure to achieve such milestones or a perception that the milestones may not be achieved will materially and adversely affect the Company and the value of its common stock.

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, 2023, the Company had an accumulated deficit of $547.9 million. During the three months ended March 31, 2023, the Company incurred net loss of $0.3 million and used $0.4 million of cash in operating activities. The Company expects to continue to generate operating losses for the foreseeable future. The Company expects that its cash and cash equivalents of $19.4 million at March 31, 2023 will allow the Company to continue its operations beyond 2027, which the Company estimates is beyond the latest date that the longest-term potential Ipsen milestone may be achieved. The continued viability of the Company beyond that point is dependent on its ability to raise additional capital to finance its operations or to reduce operating expenses. There can be no assurance that the Company will be able to obtain sufficient capital to cover its costs on acceptable terms, if at all.

The Company expects that it would seek to finance any future cash needs through a combination of divestitures of its rights under the Ipsen and Elevation agreements, equity offerings and debt financings. There can be no assurance as to the timing, terms or consummation of any divestiture or financing, and the terms of any such financing may adversely affect the holdings or the rights of the Company’s stockholders or require the Company to relinquish rights to certain of its revenue streams or product candidates.