PARPi Combination in First-Line mCRPC: A Systematic Review and Meta-Analysis

What is it about?

This meta-analysis of three Phase III randomized controlled trials (PROpel, MAGNITUDE, and TALAPRO-2) found that the addition of poly (adenosine diphosphate-ribose) polymerase inhibitors (PARPi) to androgen receptor axis-targeted agents (ARAT) in first-line metastatic castrate-resistant prostate cancer (mCRPC) improved radiographic progression-free survival (rPFS) across subgroups, with the greatest benefit in BRCA1/2 mutated (BRCA1/2m) patients. Overall survival (OS) benefits were inconsistent, but significant in the homologous recombination repair-mutated (HRRm) cohort. The PARPi/ARAT combination was associated with a 45% relative risk increase in Grade ≥3 treatment-emergent adverse events (TEAEs), including a 6.22-fold increase for Grade ≥3 anaemia. The addition of PARPi to ARAT in the first-line mCRPC setting is associated with rPFS benefits, but the current suggestion is to selectively offer this combined approach to HRRm patients, preferentially BRCA1/2m, until further OS data and methods to better identify patients most likely to benefit become available.

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Why is it important?

This research is important as it provides a comprehensive meta-analysis of all published Phase III randomized controlled trials comparing the combination of first-line poly (adenosine diphosphate-ribose) polymerase inhibitors (PARPi) plus androgen receptor axis-targeted agents (ARAT) vs placebo/ARAT in patients with metastatic castrate-resistant prostate cancer (mCRPC). The study highlights the benefits and risks associated with this treatment approach, providing valuable insight for healthcare professionals and patients when making treatment decisions. Key Takeaways: 1. The addition of PARPi to ARAT in the first-line mCRPC setting is associated with improved radiographic progression-free survival (rPFS) across subgroups, with the greatest magnitude of benefit in BRCA1/2m patients. 2. Significant overall survival (OS) benefits were observed in the HRRm cohort irrespective of whether the MAGNITUDE crude or adjusted HR definitions were used, while significant OS benefits in the BRCA1/2m cohort were only observed when the MAGNITUDE IPCW HR definition was used. 3. The PARPi/ARAT combination is associated with a 45% relative risk increase in Grade ≥3 treatment-emergent adverse events (TEAEs), including a 6.22-fold increase for Grade ≥3 anaemia. 4. Currently, the combined approach is suggested to be selectively offered to HRRm patients, preferentially BRCA1/2m, until further OS data and methods to better identify patients most likely to benefit from this combined approach become available.