Tazemetostat in relapsed/refractory follicular lymphoma: a propensity score–matched analysis of E7438-G000-101 trial outcomes

Purpose: In the tazemetostat E7438-G000-101 trial of relapsed/refractory (R/R) follicular lymphoma (FL), apparent superior efficacy was suggested for mutant-type (MT) EZH2 versus wild-type (WT) status. However, clinical disparities might have contributed to this conclusion. This study aimed to estimate outcomes after minimizing differences in baseline characteristics. Methods: Propensity scores for each participant with WT (n = 54) and MT (n = 45) status were generated based on the likelihood of being selected given their baseline characteristics. Participants were matched using a 1:1 nearest-neighbor approach. Results: The propensity-matched sample included 56 participants (28 WT, 28 MT). Objective response rates (95% confidence interval [CI]) were 35% (22–48) in WT and 69% (55–83) in MT prior to matching and 50% (31–69) in WT and 71% (54–88) in MT after matching. Median progression-free survival values (95% CI) were 11.1 (5.4–16.7) in WT and 13.8 months (11.1–22.1) in MT prior to matching and 14.3 (11.1–∞]) and 14.8 months (10.7–∞]) in WT and MT matched groups, respectively. Conclusions: This analysis suggests that efficacy outcomes for tazemetostat observed in participants with WT EZH2 R/R FL may have been similar to those in participants with MT had the 2 cohorts been more closely matched.