EHA 2018: Tazemetostat in Relapsed or Refractory Follicular Lymphoma
Positive interim data were recently presented from an ongoing phase II study of tazemetostat—a potent, selective, orally available EZH2 inhibitor—as a monotherapy for patients with relapsed or refractory follicular lymphoma. The data, presented by Salles et al at the 23rd Annual Congress of the European Hematology Association (EHA) (Abstract S100), showed that tazemetostat demonstrated meaningful clinical activity and was generally well tolerated in these heavily pretreated patients.
Study Findings
Interim data as of May 1, 2018, included 82 evaluable patients across two cohorts, prospectively assigned by EZH2 status. In the EZH2–activating mutation cohort (n = 28), an objective response rate of 71% was observed; 11% of patients achieved a complete response and 61% achieved a partial response.
In addition, 29% achieved stable disease as best response; of those, 21% are still on-study with the potential to respond. All patients in this cohort experienced reduction in tumor burden, and no patients experienced progressive disease as best response. At the time of this analysis, the median progression-free survival was 49 weeks, and the median duration of response was 32 weeks, with both endpoints continuing to mature.
In the fully enrolled cohort of follicular lymphoma patients with wild-type EZH2 (n = 54), the objective response rate was 33%; 6% achieved a complete response, and 28% achieved a partial response. An additional 31% of patients achieved stable disease as best response, including one patient who is still receiving treatment.
At the time of this analysis, the median progression-free survival was 30 weeks and median duration of response was 76 weeks. The median duration of response figure continues to mature, with more than half of the responders still on therapy.
“I am impressed by the sustained clinical activity and the good tolerability of tazemetostat in this heavily pretreated patient population. This is important for patients with relapsed or refractory follicular lymphoma, as both the response rates and durations of response usually tend to decrease with each successive line of treatment,” said Gilles Salles, MD, PhD, of the University Hospital of Lyon, France, and President of the Lymphoma Study Association Cooperative Group. “I believe tazemetostat has the potential to fill a significant unmet need for these patients, and continued investigation of tazemetostat as single agent or in combination with other agents is warranted.”
Tazemetostat was generally well tolerated in this study. Interim safety results at the time of this analysis show only 6% of patients discontinued treatment due to treatment-related adverse events. Such events of grade 3 or higher, the most frequent of which included thrombocytopenia, anemia, asthenia, and fatigue, were reported across 17% of patients.
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