BI-1808 (TNFR2 IgG1 mAb; Treg-depleting) + pembrolizumab delivers 24% ORR in heavily pretreated ovarian cancer

BI-1808 is an anti-TNFR2 IgG1 monoclonal antibody designed to block TNF-α/TNFR2 signaling and, via FcγR engagement, deplete tumor Tregs and reprogram myeloid cells—mechanistically complementary to PD-1 blockade with pembrolizumab. In the Phase 2a ovarian cancer sub-cohort of 19-BI-1808-01 (NCT04752826), 24 patients were treated with BI-1808 1000 mg Q3W + pembrolizumab 200 mg Q3W; among 17 response-evaluable patients, confirmed ORR was 24% (4 PR) with DCR 65%, including multiple prolonged SD cases ongoing >10 months (activity noted in both high-grade serous and clear cell). Safety was described as generally tolerable with manageable immune-related AEs and no discontinuations; numerically, the ORR exceeds pembrolizumab monotherapy in recurrent ovarian cancer (ORR 8% in KEYNOTE-100), but cross-trial comparisons are limited and mature PFS/OS are not yet reported.