BioInvent International AB announced six additional patients have been treated in the intravenous (IV) arm of its Phase 1/2 trial (NCT04219254; KEYNOTE-A04) of the novel anti-FcyRIIB antibody BI-1206 in combination with KEYTRUDA®? (pembrolizumab), MSD's (Merck & Co. Inc., Rahway, NJ., USA) anti-PD-1 therapy, in solid tumors.

The additional patients have been treated at a dose of 1 mg/kg. Previous observations had revealed that BI-1206 may enhance the activity of pembrolizumab in patients who have previously progressed on PD-1/PDL-1 targeting therapies. In addition to the patients previously reported, (1 case of pseudo progression and 1 partial response (PR), new data now show one patient experiencing a long-lasting stable disease, with more than 80 weeks of treatment in the study, and another patient experiencing a PR.

Both patients have melanoma, and both had previously been treated with immune checkpoint inhibitors. The latter had progressed after previous lines of those agents. The first PR observed is still responding and has been on treatment for more than 90 weeks.

BioInvent will share additional updates from the IV arm of the trial during the second half of 2023. The study is recruiting patients with advanced solid tumors who had progressed on prior treatments including PD-1/PD-L1 immune checkpoint inhibitors. Patients receive a three-week cycle of BI-1206 in combination With rituximab in non-Hodgkin's lymphoma (NHL), is also continuing.