On December 22, the U.S. Food and Drug Administration (FDA) approved mosunetuzumab-axgb (Lunsumio) for the treatment of adults with relapsed or refractory follicular lymphoma after two or more lines of systemic therapy. Mosunetuzumab-axgb is a CD20/CD3 T-cell–engaging bispecific antibody and represents a new class of fixed-duration, off-the-shelf cancer immunotherapy. Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial.
The drug was granted accelerated approval based on response rate reported in the phase II GO29781 study (ClinicalTrials.gov identifier NCT02500407). GO29781 is a multicenter, open-label, dose-escalation and dose-expansion trial evaluating the safety, efficacy, and pharmacokinetics of mosunetuzumab-axgb in people with relapsed or refractory B-cell non-Hodgkin’s lymphoma. Outcome measures include complete response rate (best response) by independent review facility (primary endpoint), objective response rate, duration of response, progression-free survival, safety, and tolerability (secondary endpoints).
More About GO29781
Results from the study showed high and durable response rates. An objective response was seen in 80% of patients treated with mosunetuzumab-axgb, and a majority of these patients (57%) maintained responses for at least 18 months The median duration of response among those who responded was 22.8 months. A complete response was achieved in 60% of patients.
Among 218 patients with hematologic malignancies who received mosunetuzumab-axgb at the recommended dose, the most common adverse event was cytokine-release syndrome, the median duration of which was 3 days. Other common adverse events (≥ 20%) included fatigue, rash, pyrexia, and headache.
Mosunetuzumab-axgb is administered as an intravenous infusion for a fixed duration, which allows for time off therapy, and can be infused in an outpatient setting. Hospitalization may be needed to manage select adverse events.
