Epizyme slides on worse-than-expected early PhII data in NHL

Epizyme was off about 6% in early trading as it reported preliminary data in an ongoing Phase II trial of its lead candidate tazemetostat. The oral drug is a first-in-class EZH2 inhibitor that the Cambridge, MA-based company hopes to launch as early as the second quarter of 2018 in genetically defined solid tumors, with non-Hodgkin lymphoma (NHL) to follow about a year later.

In the latest data, the “response rate is lower than expected” noted analyst Simos Simeonidis of RBC Capital Markets. The overall response rate (ORR) was 28%--lower than the 56% to 60% that was reported in Phase I data, he said. Simeonidis notes that he expects the responses to improve over time. Almost half of the patients included in the analysis had been on the treatment for less than 5 months.

“Patients with relapsed or refractory NHL are often faced with limited treatment options, particularly those who are highly refractory or whose disease is multiply relapsed as we have seen in this study population,” said Dr. Franck Morschhauser of the Centre Hospitalier Régional Universitaire de Lille in France and the primary investigator on the Phase II study, in a statement. “These patients are in need of new therapeutic options, and while these data are early, we are encouraged and look forward to further understanding the impact that tazemetostat could have on patients as the trial proceeds.”

In the study, the company’s Independent Data Monitoring Committee found that four of the five study genetically defined cohorts had surpassed futility with one or two responses: diffuse large B-cell lymphoma (DLBCL) with Germinal Center B-cell (GCB) subtype and EZH2 mutations; DLBCL with GCB subtype and wild-type EZH2; DLBCL with non-GCB subtype; and, follicular lymphoma (FL) with EZH2 mutations. The fifth cohort in patients with FL with wild-type EZH2 has not yet reached futility assessment.

The primary endpoint of the Phase II trial is ORR with secondary endpoints of progression-free survival (PFS) and duration of response. The safety profile in the Phase II is consistent, so far, with what was observed in Phase I.

Tazemetostat is the cornerstone of Epizyme’s market strategy--and a core part of its strategic vision as well. The company said on a May conference call that it expects announce a “collaboration agreement with a leader in oncology to combine tazemetostat with an anti-PD1 or PDO1 agent for the treatment of NHL and potentially other types of cancer.”

The company anticipated on that call that such a deal would offer 50/50 expense sharing for the combination approach with the two novel agents. It said that it expected to sign such an agreement by mid-year with combo trials starting shortly thereafter. Epizyme already has pipeline deals with GlaxoSmithKline ($GSK) and Celgene ($CELG).

Ultimately, Epizyme has said it expects to develop tazemetostat as a frontline NHL treatment. It partnered in May with the Lymphoma Academic Research Organization for a frontline combination trial with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone), a standard treatment in newly diagnosed DLBCL, as a frontline treatment in elderly high-risk patients with DLBCL.

Investors haven’t been particularly friendly to the development-stage Epizyme as the overall biotech market has slumped. Its shares have fallen almost 60% in the last year--almost twice the decline in the Nasdaq Biotechnology Index.

- here is the release

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