The Company	3 Months Ended
Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
The Company	1. The Company Epizyme, Inc. (collectively referred to with its wholly owned, controlled subsidiary, Epizyme Securities Corporation, as “Epizyme” or the “Company”) is a commercial-stage biopharmaceutical company that is committed to rewriting treatment for people with cancer through the discovery, development, and commercialization of novel epigenetic medicines. The Company aspires to change the standard of care for patients and physicians by developing targeted medicines with fundamentally new mechanisms of action directed at specific causes of hematological malignancies and solid tumors. Through March 31, 2022, in addition to revenues from product sales, the Company has raised an aggregate of $1,650.2 million to fund its operations. This includes $268.8 million of non-equity funding through its collaboration agreements, $368.1 million of funding, consisting of $150.0 million in equity funding received through agreements with RPI Finance Trust ("RPI"), and $218.1 million in debt financing received through a loan agreement with BioPharma Credit Investments V (Master) LP and BPCR Limited Partnership (as transferee of BioPharma Credit Investments V (Master) LP’s interest as a lender) (the "Lenders"), $937.3 million from the sale of common stock and series A convertible preferred stock (the “Series A Preferred Stock”) in the Company’s public offerings and at-the-market offerings and $76.0 million from the sale of redeemable convertible preferred stock in private financings prior to the Company’s initial public offering in May 2013. As of March 31, 2022, the Company had $199.7 million in cash, cash equivalents and marketable securities. In 2020, the Company’s EZH2 inhibitor, tazemetostat, was approved in the United States as TAZVERIK for the treatment of epithelioid sarcoma ("ES"), and follicular lymphoma ("FL"). Commercial sales of TAZVERIK for the treatment of ES commenced in the first quarter of 2020 and commercial sales of TAZVERIK for the treatment of FL commenced in the end of the second quarter of 2020. The Company commenced active operations in early 2008. Since its inception, the Company has generated an accumulated deficit of $1,295.3 million through March 31, 2022 and will require substantial additional capital to fund its research, development, and commercialization efforts. The Company is subject to risks common to companies in the biotechnology industry, including, but not limited to, risks of failure of commercialization, clinical trials and preclinical studies, the need to obtain additional financing to fund the future development and commercialization of tazemetostat and the rest of its pipeline, the need to obtain marketing approval for its product candidates, the need to successfully commercialize and gain market acceptance of TAZVERIK and of any product candidates that may be approved in the future, the impact of the COVID-19 pandemic on the Company’s business, results of operations, and financial condition, dependence on key personnel, protection of proprietary technology, compliance with government regulations, development by competitors of technological innovations and ability to transition from clinical-stage manufacturing to commercial-stage production, marketing, and sale of products. Operating Cost Reduction In August 2021, the Company implemented a cross-functional reduction of approximately 11% of its then current workforce under a cost reduction plan. Affected employees were offered separation benefits, including severance payments along with temporary healthcare coverage assistance. The severance and termination-related costs totaled approximately $2.0 million, $1.6 million of which were recorded as selling general and administrative expenses and $0.4 million of which was recorded as research and development expenses in the third quarter of 2021. The Company expects that payments of these costs will be made through August 2022. In March 2022, the Company implemented further reductions of its expenses, including a pipeline reprioritization. Given the breadth of the Company’s then-current tazemetostat clinical development program, the Company decided to discontinued enrollment in its Phase 2 study of tazemetostat in combination with rituximab with FL in the third-line or later treatment settings (SYMPHONY-2, EZH-1401), as well as in its Phase 1/1b basket study evaluating tazemetostat combinations in patients with solid tumors (EZH-1301). The Company has enrolled five patients in the EZH-1401 study and one patient in the EZH-1301 study and plans to continue to follow the patients currently enrolled in each of these two studies. The decision to discontinue these studies was based on evolving market dynamics and a continued focus on optimizing the Company’s investments and eliminating potentially overlapping studies. The Company continues to study tazemetostat in combination with other therapies for both hematologic and solid tumor malignancies, both in ongoing Company-sponsored studies as well as investigator-initiated studies. In addition, as part of the cost reduction plan, the Company implemented a cross-functional workforce reduction of approximately 12% of the Company’s then-current employees. The severance and termination related costs totaled approximately $2.5 million, $1.7 million of which were recorded as selling general and administrative expenses and $0.8 million of which were recorded as research and development expenses in the first quarter of 2022. The Company expects that payments of these costs will be made through December 2022.

The Company

3 Months Ended

Mar. 31, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

1. The Company

Epizyme, Inc. (collectively referred to with its wholly owned, controlled subsidiary, Epizyme Securities Corporation, as “Epizyme” or the “Company”) is a commercial-stage biopharmaceutical company that is committed to rewriting treatment for people with cancer through the discovery, development, and commercialization of novel epigenetic medicines. The Company aspires to change the standard of care for patients and physicians by developing targeted medicines with fundamentally new mechanisms of action directed at specific causes of hematological malignancies and solid tumors.

Through March 31, 2022, in addition to revenues from product sales, the Company has raised an aggregate of $1,650.2 million to fund its operations. This includes $268.8 million of non-equity funding through its collaboration agreements, $368.1 million of funding, consisting of $150.0 million in equity funding received through agreements with RPI Finance Trust ("RPI"), and $218.1 million in debt financing received through a loan agreement with BioPharma Credit Investments V (Master) LP and BPCR Limited Partnership (as transferee of BioPharma Credit Investments V (Master) LP’s interest as a lender) (the "Lenders"), $937.3 million from the sale of common stock and series A convertible preferred stock (the “Series A Preferred Stock”) in the Company’s public offerings and at-the-market offerings and $76.0 million from the sale of redeemable convertible preferred stock in private financings prior to the Company’s initial public offering in May 2013. As of March 31, 2022, the Company had $199.7 million in cash, cash equivalents and marketable securities.

In 2020, the Company’s EZH2 inhibitor, tazemetostat, was approved in the United States as TAZVERIK for the treatment of epithelioid sarcoma ("ES"), and follicular lymphoma ("FL"). Commercial sales of TAZVERIK for the treatment of ES commenced in the first quarter of 2020 and commercial sales of TAZVERIK for the treatment of FL commenced in the end of the second quarter of 2020.

The Company commenced active operations in early 2008. Since its inception, the Company has generated an accumulated deficit of $1,295.3 million through March 31, 2022 and will require substantial additional capital to fund its research, development, and commercialization efforts. The Company is subject to risks common to companies in the biotechnology industry, including, but not limited to, risks of failure of commercialization, clinical trials and preclinical studies, the need to obtain additional financing to fund the future development and commercialization of tazemetostat and the rest of its pipeline, the need to obtain marketing approval for its product candidates, the need to successfully commercialize and gain market acceptance of TAZVERIK and of any product candidates that may be approved in the future, the impact of the COVID-19 pandemic on the Company’s business, results of operations, and financial condition, dependence on key personnel, protection of proprietary technology, compliance with government regulations, development by competitors of technological innovations and ability to transition from clinical-stage manufacturing to commercial-stage production, marketing, and sale of products.

Operating Cost Reduction

In August 2021, the Company implemented a cross-functional reduction of approximately 11% of its then current workforce under a cost reduction plan. Affected employees were offered separation benefits, including severance payments along with temporary healthcare coverage assistance. The severance and termination-related costs totaled approximately $2.0 million, $1.6 million of which were recorded as selling general and administrative expenses and $0.4 million of which was recorded as research and development expenses in the third quarter of 2021. The Company expects that payments of these costs will be made through August 2022.

In March 2022, the Company implemented further reductions of its expenses, including a pipeline reprioritization. Given the breadth of the Company’s then-current tazemetostat clinical development program, the Company decided to discontinued enrollment in its Phase 2 study of tazemetostat in combination with rituximab with FL in the third-line or later treatment settings (SYMPHONY-2, EZH-1401), as well as in its Phase 1/1b basket study evaluating tazemetostat combinations in patients with solid tumors (EZH-1301). The Company has enrolled five patients in the EZH-1401 study and one patient in the EZH-1301 study and plans to continue to follow the patients currently enrolled in each of these two studies. The decision to discontinue these studies was based on evolving market dynamics and a continued focus on optimizing the Company’s investments and eliminating potentially overlapping studies. The Company continues to study tazemetostat in combination with other therapies for both hematologic and solid tumor malignancies, both in ongoing Company-sponsored studies as well as investigator-initiated studies. In addition, as part of the cost reduction plan, the Company implemented a cross-functional workforce reduction of approximately 12% of the Company’s then-current employees. The severance and termination related costs totaled approximately $2.5 million, $1.7 million of which were recorded as selling general and administrative expenses and $0.8 million of which were recorded as research and development expenses in the first quarter of 2022. The Company expects that payments of these costs will be made through December 2022.