A phase Ib/II study of niraparib combination therapies for the treatment of metastatic castration-resistant prostate cancer (NCT03431350).

Abstract

TPS5087 Background: Assessing multiple therapies in a single clinical trial can facilitate the rapid identification of new agents for the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC). Niraparib (Nirap) is a highly selective PARP inhibitor, with potent activity against PARP-1 and PARP-2 deoxyribonucleic acid (DNA)-repair polymerases. PARP inhibition may be especially lethal in tumor cells with genetic DNA damage response deficits (DRD). Based on promising preclinical and clinical data, this study is designed as a master protocol with nirap as a backbone therapy. Combination 1 assesses the safety and efficacy of nirap plus JNJ-63723283 (JNJ-283), an anti-PD-1 monoclonal antibody. Combination 2 assesses nirap plus abiraterone acetate and prednisone (AA-P). Methods: This multicenter, global, open-label study is currently open at 18 sites in 5 countries of the planned XX sites, and is enrolling patients with mCRPC who have progressed on ≥1 androgen-receptor targeted therapy for mCRPC. Enrollment at time of abstract submission was 25 for combination 1. When combined with AA-P, the RP2D has been determined to be nirap 200 mg. The recommended phase-2 dose (RP2D) of nirap plus JNJ-283 was determined in Part 1 based on the incidence of specified adverse events and PK data to be 480 mg every 4 weeks. For Part 2 of the study, patients are assigned to receive oral niraparib daily plus JNJ-283 infusions once every four weeks until disease progression, unacceptable toxicity, death, study termination. Part 2 is described in the table. Clinical trial information: NCT03431350. [Table: see text]