Lymphoma

High objective response and complete response rates observed with mosunetuzumab in patients with relapsed/refractory follicular lymphoma.

A safety, efficacy and pharmacokinetic study of BTCT4465A (mosunetuzumab) as a single agent and combined with atezolizumab in non-Hodgkin's lymphoma (NHL) and chronic lymphocytic leukemia (CLL). ClinicalTrials.gov. Updated July 8, 2022. There were 4 (4%) patients who withdrew from the study due to AEs, including grade 2 cytokine release syndrome, grade 4 cytokine release syndrome, both of which were considered related to mosunetuzumab. The other 2 discontinuations were due to grade 2 Hodgkin lymphoma and grade 4 Epstein-Barr viraemia, both of which were not related to the study. At the median follow-up, patients were treated with a median of 8 cycles of mosunetuzumab and 60% completed initial treatment. Further, at 18 months, the event-free survival was 61.0% (95% CI, 50.0%-72.0%) and OS rate was 89.6% (95% CI, 82.5%-96.6%). In the pivotal studies of the PI3K inhibitors, adverse events leading to discontinuation occurred in 15%-35% of patients,” wrote the study investigators. Between May 2, 2019, and September 25, 2020, 90 patients were enrolled with the majority of patients men (61%), White (82%), and had stage III or IV disease (77%). Sixty-nine percent of patients were refractory to their last therapy, the median number of prior lines of therapy was 3 (range, 2-4), 59% had an ECOG performance status of 0, and before the study entry, all patients received anti-CD20 therapies and alkylating agents. The median duration of CR was NR (95% CI, 14.6-NR) as well as both the median OS and time to next treatment. Each of the CRs were confirmed by PET and bone marrow examination. Enrollment was open to patients aged 18 years or older with histologically confirmed disease, an ECOG performance status of 0-1, and adequate hepatic, hematologic, and renal function. The study met its primary efficacy endpoint, with a complete response rate of 60.0%,” wrote the study investigators. This observed response rate was significantly higher than the historic control copanlisib (Aliqopa; 14%; P <.0001).