Targeted Next-Generation Sequencing in Men with Metastatic Prostate Cancer: a Pilot Study

Introduction Tumor profiling by targeted next-generation sequencing (tNGS) and personalized treatment based on these results is becoming increasingly common in patients with metastatic solid tumors, but it remains unclear whether this strategy results in benefit to patients with metastatic prostate cancer (mPCa). Objective To assess the clinical utility of tNGS in treatment decision-making for patients with mPCa. Patients and Methods Patients with available genomic profiling using tumor tissue (FoundationOne, F1) or cell-free DNA (FoundationACT, Guardant360) were included. Targetable genomic alterations (tGA) included a change in the copy number or mutations in DNA repair genes, mismatch repair genes, PTEN, cyclin-dependent kinases, ERBB2, BRAF, TSC, and the PIK3/mTOR pathway. Results The study included 66 patients, 86% of which had metastatic castration-resistant prostate cancer (mCRPC), and who had received a median of 3 (range 0-7) treatments prior to tNGS. The most frequent alterations were found in TP53 (42%), PTEN (35%), androgen receptor (AR) (30%), DNA repair (30%), PIK3CA signaling pathway (21%), cyclin-dependent kinases (15%), BRAF (9%), and MMR/MSI (6%) genes. Among the 45 (68%) tGA+ patients, tNGS influenced treatment in 13 (29%) [PARP inhibitor (n = 7), mTOR inhibitor (n = 4), anti-PD-1 (n = 2), anti-HER2 (n = 1)]. The median progression-free survival (PFS) was 4.1 months [95% confidence interval (CI), 2.8-5.4]. Among tGA+ patients who did not receive tNGS-based therapy, systemic treatment (n = 17) included chemotherapy (71%), new generation anti-androgen therapy (24%), and cabozantinib (6%); the median PFS was 4.3 months (95% CI, 2.6-6.0; p = 0.7 for tGA+ with personalized therapy vs. tGA+ without personalized therapy). Conclusion In this cohort, the use of tNGS was feasible, detected frequent genomic alterations, and was used late in the disease course. Further studies and larger portfolios of targeted therapy trials are needed to maximize the benefit of tNGS in this population.