As reported in the Journal of Clinical Oncology by L. Elizabeth Budde, MD, PhD, and colleagues, extended follow-up of the dose-escalation phase of a phase I/II trial showed that the CD20 x CD3 T-cell–engaging bispecific antibody mosunetuzumab-axgb—given as an off-the-shelf fixed-duration outpatient treatment—produced durable responses in patients with relapsed or refractory B-cell non-Hodgkin lymphoma (NHL).
L. Elizabeth Budde, MD, PhD
Study Details
The current analysis included 67 patients with indolent NHL and 129 with aggressive NHL who received mosunetuzumab doses of 0.4, 1.0, and 2.8 mg or 1.0, 2.0, and 60.0 mg on cycle days 1, 8, and 15 for 8 or 17 cycles based on tumor response.
Key Findings
Median follow-up was 3.5 years. Across dose levels, complete or partial response was achieved in 44 of 67 patients (65.7%) with indolent NHL (complete response in 33; 49.3%) and in 47 of 129 patients (36.4%) with aggressive NHL (complete response in 28; 21.7%).
Among responders with indolent NHL, median duration of response was 23.2 months (95% confidence interval [CI] = 13.8 months to not estimable) among all responders and not reached (95% CI = 21.0 months to not estimable) among those with a complete response. No relapses were observed beyond 26 months in patients with a complete response.
Among responders with aggressive NHL, median duration of response was 7.8 months (95% CI = 4.6–22.8 months) among all responders and 28.8 months (95% CI = 11.5 months to not estimable) among those with a complete response.
In patients with indolent or aggressive NHL with partial response, median response durations were 7.8 months (95% CI = 4.3–8.7 months) and 3.3 months (95% CI = 2.6–4.6 months), respectively.
Among 12 patients with a complete response—8 with indolent and 4 with aggressive NHL—whose disease progressed after mosunetuzumab study treatment and were retreated with fixed-duration mosunetuzumab, 83.3% had an objective response, and 58.3% had a second complete response.
The investigators concluded: “Our study reports the longest follow-up using bispecific antibodies in patients with B-cell non-Hodgkin lymphoma and demonstrates that mosunetuzumab can mediate durable remissions with time-limited treatment.”
Nancy L. Bartlett, MD, of Siteman Cancer Center, Washington University School of Medicine in St. Louis, is the corresponding author of the Journal of Clinical Oncology article.
Disclosure: The study was supported by Genentech, Inc. For full disclosures of the study authors, visit ascopubs.org.
