Royalty Pharma Acquires Global Royalty Rights to Tazemetostat for $330 Million as FDA Approval Nears

Tazemetostat is a first-in-class oral EZH2 (enhancer of zeste homolog 2) inhibitor developed by Epizyme, clinically developed for the treatment of indications such as epithelioid sarcoma and follicular lymphoma. In March 2011, Eisai entered into a global strategic collaboration with Epizyme for epigenetic drug discovery and development based on the EZH2 technology platform, paying an upfront fee to Epizyme and covering the research and development costs for candidate drugs from this platform up to the stage prior to human proof-of-concept. In March 2015, the two parties amended and supplemented the cooperation agreement, under which Eisai became responsible for the development and commercialization of tazemetostat in Japan, paying royalties to Epizyme based on sales of tazemetostat in the Japanese market. Epizyme is responsible for the development and commercialization of tazemetostat in all regions outside Japan, and is required to pay Eisai development and regulatory milestones, as well as royalties based on sales revenue in regions outside Japan.

Structural Formula of Tazemetostat

On November 5, Royalty Pharma, an institution specializing in investments in pharmaceutical patent licensing revenues, announced the acquisition from Eisai of global rights to tazemetostat outside Japan for $330 million, including a $110 million upfront payment and $220 million in milestone payments contingent upon FDA approval for specific indications. Additionally, Royalty Pharma will make a $100 million equity investment in Epizyme at a price of $15 per share, with the option to purchase an additional $100 million worth of Epizyme’s publicly traded shares in the future.

Tazemetostat is the flagship investigational drug of Epizyme, a renowned company in the field of epigenetics. On July 23 this year, Epizyme submitted a marketing application to the U.S. Food and Drug Administration (FDA) seeking accelerated approval for tazemetostat for the treatment of metastatic or locally advanced epithelioid sarcoma in patients who are not candidates for curative surgery. The application was granted Priority Review status by the FDA. The submission is based on data from a single-arm, Phase II study involving 62 patients with epithelioid sarcoma, which were previously presented at the ASCO 2019 Annual Meeting. The data demonstrated that tazemetostat treatment achieved clinically meaningful and durable responses, with a favorable safety and tolerability profile.

The results showed that as of September 17, 2018, among the 62 patients, the objective response rate (ORR) was 15%, the median duration of response (DoR) had not been reached, the disease control rate (DCR) was 26%, and the median overall survival (OS) was 82.4 months. The 62 patients included 24 treatment-naïve patients and 38 patients with relapsed/refractory disease. Among the treatment-naïve patients, the ORR was 25%, the DoR was 41.1 months, the DCR was 42%, and the median OS had not been reached; among the patients with relapsed/refractory disease, the ORR was 8%, the DoR had not been reached, the DCR was 16%, and the median OS was 47.4 months.

To support the transition from accelerated approval to full approval post-launch, Epizyme also plans to initiate a global, confirmatory, randomized, controlled clinical trial. The study is designed to enroll approximately 150 patients with epithelioid sarcoma to evaluate the efficacy and safety of tazemetostat in combination with doxorubicin versus placebo in combination with doxorubicin.

Dr. Takashi Owa, Vice President and Chief Medical Innovation Officer at Eisai, stated, “The transfer of global rights to tazemetostat was primarily undertaken to secure funding to support the development of more innovative therapies in Eisai’s product pipeline.”