A phase 1b study of the anti-PD-1 monoclonal antibody BGB-A317 (A317) in combination with the PARP inhibitor BGB-290 (290) in advanced solid tumors.

48Background: The release of tumor-associated antigens may enhance the response to immunotherapy. BGB-A317, a humanized IgG4 variant monoclonal antibody engineered to have no Fc gamma receptor binding, targets the programmed cell death-1 (PD-1) receptor. It is being developed in solid and hematologic malignancies at a dose of 200 mg IV Q3W. BGB-290, a potent inhibitor of PARP 1/2, is hypothesized to promote neoantigen release that may potentially increase the efficacy of BGB-A317. A phase 1 study identified 60 mg BID as the recommended Phase 2 dose (RP2D) for BGB-290. This study consists of initial dose escalation to determine the maximum-tolerated dose (MTD), safety, pharmacokinetic (PK) profile, and preliminary antitumor activity of the combination, followed by expansion into ovarian, breast, prostate, gastric, bladder, pancreatic and small cell lung cancers. Methods: Cohorts of 6–12 patients with advanced solid tumors were treated in each of 5 planned dose levels (DLs). In DLs 1–3, BGB-290 doses ranged...