Mosunetuzumab is effective and well tolerated in older patients with relapsed/refractory follicular lymphoma: Subgroup analysis of a phase I/II study.

A high unmet need for novel, safe and effective therapies exists among older patients with non-Hodgkin lymphoma (NHL). We report safety and efficacy of mosunetuzumab in a subgroup analysis of a phase I/II study, which examined the prognostic impact of age in 218 patients with relapsed/refractory (R/R) B-cell NHL (B-NHL; ≥65 years, n = 102; <65 years, n = 116) from the phase I expansion cohort (NCT02500407) and further evaluated 90 patients with R/R follicular lymphoma (FL; ≥65 years, n = 30; <65 years, n = 60) from the pivotal cohort. The most common adverse event (AE) was cytokine release syndrome, occurring less frequently in older versus younger (33.3% vs. 44.8%) patients with B-NHL. Serious AEs were similar in older versus younger patients (45.1% vs. 46.6%). For patients with R/R FL, overall and complete response rates were numerically higher in older (86.7% and 70.0%, respectively) versus younger (76.7% and 55.0%) patients. Median progression-free survival and time-to-next treatment were 17.9 months and not reached in older patients versus 12.0 and 18.1 months in younger patients. These findings demonstrate mosunetuzumab is effective and well-tolerated across age groups in patients with R/R FL. Additional studies are warranted to further evaluate the safety and efficacy of mosunetuzumab in older patients with B-NHL.