Olaparib previous demonstrated the antitumor activity in unselected mCRPC patients in the TOPARP-A trial. TOPARP-B is the second part of the larger phase II trial to evaluate olaparib efficacy in patients with mCRPC selected for alterations in DNA damage repair genes. A total of 98 patients were enrolled into the trial. Overall, 47% of patients with DNA repair defects responded to olaparib, and the median progression free survival (mPFS) was 5.5 months. Responses were also reported based on specific gene alterations. Patients with BRCA1/2 alterations had the highest response rate at 83.3%. The response rate in patients with ATM, CKD12, and PLAB2 alterations were 36.8%, 25.0% and 57.1%, respectively. The results show that olaparib could be a new treatment option among mCRPC patients carrying alterations in DNA damage repair genes.
J Clin Oncol 37, 2019 (suppl; abstr 5005)