Graf RP, Fisher V, Mateo J, et al. - Findings indicate the potential of AR amplification (ARamp) status to serve as a predictive biomarker for poor effectiveness of novel hormonal therapy (NHT) vs taxanes in metastatic castration-resistant prostate cancer in situations where both options are considered.

• In this retrospective cohort study, an established comprehensive genomic profiling system was used.

• Worse relative prostate-specific antigen response on NHT vs taxanes was evident in patients with ARamp or PTEN aberrations (PTENalt), relative to those without.

• ARamp, PTENalt, and RB1 aberrations were identified as poor prognostic factors overall and showed significant treatment interactions, suggesting decreased hazards of therapy switch and death on taxanes vs NHT.

• In the sequential cohort, consistent links supporting increased advantage from subsequent taxane despite prior NHT treatment line were noted only for ARamp.