Treatment Patterns and Clinical Outcomes Among Patients With Metastatic Prostate Cancer Harboring Homologous Recombination Repair Mutations

This study generated real-world evidence among patients with metastatic castration-resistant prostate cancer (mCRPC) harboring homologous recombination repair (HRR) mutations. Treatment patterns were similar to mCRPC patients regardless of HRR-mutation status. Median OS was 3 years from initiation of first-line therapy and decreased for subsequent lines. Results highlight a need to identify optimal treatments and sequencing for patients with HRR-mutated mCRPC. Background: There is currently limited literature assessing the real-world treatment patterns and clinical outcomes of patients with metastatic castration-resistant prostate cancer (mCRPC) and homologous recombination repair (HRR) mutations. Methods: Medical charts were abstracted for mCRPC patients with > 1 of 12 HRR somatic gene alterations treated at US oncology centers participating in the American Association for Cancer Research Project Genomics Evidence Neoplasia Information Exchange. Treatment patterns and clinical outcomes were assessed from the initiation of first-line or later (1L + ) mCRPC therapy received on or after July 1, 2014. Results: Among 138 patients included in the study, the most common somatic HRR mutations were CDK12 (47.8%), BRCA2 (22.5%), and ATM (21.0%). Novel hormonal therapy and taxane chemotherapy were most commonly used in 1L; taxane use increased in later lines. Median overall survival (95% confidence interval [CI]) was 36.3 (30.7-47.8) months from initiation of 1L therapy and decreased for subsequent lines. Similarly, there was a trend of decreasing progression-free survival and prostatespecific antigen response from 1L to 4L + therapy. Conclusions: Treatment patterns identified in this study were similar to those among patients with mCRPC regardless of tumor HRR mutation status in the literature.