Results from an open-label Phase 2 clinical trial evaluating Epizyme’s (NASDAQ:EPZM) tazemetostat in follicular lymphoma (FL) patients, with or without EZH2 activating mutations, showed a treatment benefit. The data were presented at ASH in Orlando.
The objective response rate (ORR) in patients with an EZH2 mutation was 69% (n=31/45) as determined by an Independent Review Committee. The ORR in patients with wild-type (naturally occurring) EZH2 was 35% (n=19/54). Complete response rates were 13% (n=6/45) and 4% (n=2/54), respectively.
The rates of stable cancer were 29% (n=13/45) and 33% (n=18/54) implying disease control rates of 98% (n=44/45) and 69% (n=37/54), respectively.
Median progression-free survival was 13.8 months and 11.1 months, respectively, and median duration of response was 10.9 months and 13.9 months, respectively.
On the safety front, the most frequent serious/life-threatening treatment-related adverse events were thrombocytopenia (3%), anemia (2%), asthenia (physical weakness/lack of energy) (1%) and fatigue (1%). The discontinuation rate was 8% and the rate of dose-limiting toxicity was 9%.
Small molecule tazemetostat inhibits an enzyme called enhancer of zeste homolog 2 (EZH2), the overexpression of which is associated with many forms of cancer since it dampens genes that play key roles in suppressing tumor development.
The company plans to file a U.S. marketing application this month seeking accelerated approval for FL. Its application for epithelioid sarcoma is currently under FDA review with an Ad Com meeting scheduled for Wednesday, December 18, ahead of the agency’s January 23, 2020 action date.