Advani R, et al. - Experts clinically evaluated the efficacy and safety of Hu5F9-G4 (5F9) antibody used with rituximab in eradicating B-cell non-Hodgkin’s lymphoma cells. Encouraging activity in patients with aggressive and indolent lymphoma was demonstrated by the macrophage checkpoint inhibitor 5F9 combined with rituximab. This study did not reveal any clinically significant safety events.

Methods

• A phase 1b study involving patients with relapsed or refractory non-Hodgkin’s lymphoma was conducted.
• Patients included in this trial had diffuse large B-cell lymphoma (DLBCL) or follicular lymphoma.
• In order to determine safety and efficacy and to suggest a phase 2 dose, 5F9 (at a priming dose of 1 mg per kilogram of body weight, administered intravenously, with weekly maintenance doses of 10 to 30 mg per kilogram) was given with rituximab.

Results

• Researchers enrolled a total of 22 patients (15 with DLBCL and 7 with follicular lymphoma).
• A median of 4 (range, 2 to 10) previous therapies had been given to these patients, and 95% of them had disease that was refractory to rituximab.
• Mostly grade 1 or 2 adverse events were documented; anemia and infusion-related reactions were the most common.
• The strategy of 5F9 prime and maintenance dosing helped to mitigate anemia (an expected on-target effect).
• Rarely, dose-limiting side effects were seen.
• An approximate 100% CD47-receptor occupancy on circulating white and red cells was seen after a selected phase 2 dose of 30 mg of 5F9 per kilogram.
• An objective (ie, complete or partial) response was seen in 50% of patients; 36% had a complete response.
• Findings suggested the rates of objective response and complete response to be 40% and 33%, respectively, among patients with DLBCL and 71% and 43%, respectively, among those with follicular lymphoma.
• According to the data, 91% of the responses were ongoing at a median follow-up of 6.2 months among patients with DLBCL and 8.1 months among those with follicular lymphoma.