Olaparib in Patients With Metastatic Prostate Cancer With / Mutation: Results From the TAPUR Study.

Purpose: The TAPUR Study is a phase II basket trial that aims to evaluate activity of approved targeted agents in patients with advanced cancers with potentially actionable genomic variants. Data from a cohort of patients with metastatic castrate-resistant prostate cancer (mCRPC) and / mutations treated with olaparib are reported.

Methods: Eligible patients with measurable mCRPC were matched to treatment according to protocol-specified genomic matching rules. Patients had no remaining standard treatment options, Eastern Cooperative Oncology Group performance status 0-2, and adequate organ function. Simon's two-stage design was used with a primary end point of disease control, defined as objective response or stable disease of at least 16-week duration. Secondary end points include radiographic progression-free survival, overall survival, duration of response, duration of stable disease, and safety.

Results: Thirty patients with mCRPC with / mutations were treated with olaparib. The disease control rate was 69% (95% CI, 51 to 81), and the objective response rate was 58% (95% CI, 37 to 77). The median radiographic progression-free survival and the median overall survival were 38.4 (95% CI, 16.3 to 52.1) weeks and 76.4 (95% CI, 49.3 to 106.0) weeks, respectively. Six of 30 (20%) patients experienced grade 3-4 adverse or serious adverse events including anemia, aspiration, decreased WBC count, and fatigue.

Conclusion: Olaparib has antitumor activity in patients with mCRPC with / mutations and warrants further study to determine how to best integrate it into the standard treatment of patients with /-mutated prostate cancer.