Clovis Oncology announced that the FDA approved Rubraca (rucaparib) tablets for the treatment of adult patients with a deleterious BRCA mutation (germline and/or somatic)-associated metastatic castration-resistant prostate cancer (mCRPC) who have been treated with androgen receptor-directed therapy and a taxane-based chemotherapy. The FDA approved this indication under accelerated approval based on objective response rate (ORR) and duration of response (DOR) data from the multi-center, single arm TRITON2 clinical trial. Continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory trials. The TRITON3 clinical trial is expected to serve as the confirmatory study for the Rubraca accelerated approval in mCRPC.
The FDA approval for this third indication for Rubraca is based on efficacy data from patients with mCRPC and a deleterious BRCA mutation (germline and/or somatic) enrolled in the multi-center, single arm TRITON2 (NCT02952534) clinical trial. The major efficacy outcomes are confirmed ORR and DOR by modified RECIST version 1.1/PCWG3 criteria assessed by blinded independent radiologic review (IRR). Confirmed prostate-specific antigen (PSA) response rate is an additional prespecified endpoint.
The safety evaluation of Rubraca 600 mg twice daily as monotherapy treatment is based on an analysis of 209 patients with HRD-positive mCRPC from the multi-center, single arm TRITON2 clinical study, including 115 with BRCA-mutated mCRPC. The most common adverse reactions (greater than or equal to 20% of patients; CTCAE Grade 1-4) occurring in the BRCA mutant population (n=115) were asthenia/fatigue, nausea, anemia, ALT/AST increased, decreased appetite, constipation, rash, thrombocytopenia, vomiting, and diarrhea. The most common laboratory abnormalities (greater than or equal to 35% of patients; CTCAE Grade 1-4) were increase in ALT, decrease in leukocytes, decrease in phosphate, decrease in absolute neutrophil count, decrease in hemoglobin, increase in alkaline phosphatase, increase in creatinine, increase in triglycerides, decrease in lymphocytes, decrease in platelets, and decrease in sodium.