Feng FY, Thomas S, Saad F, et al. - This study was undertaken to investigate if molecular subtypes predict response to apalutamide, using archived primary tumor samples from the randomized, double-blind, phase 3 SPARTAN trial. This cohort study enrolled gene expression data from 233 archived samples from patients with nonmetastatic castration-resistant prostate cancer (nmCRPC) in the SPARTAN trial were generated using a human exon microarray. Researchers performed this analysis between May 10, 2018, and October 15, 2020. Individuals were assigned randomly in a 1:1 ratio to apalutamide, 240 mg/d, with androgen deprivation therapy (apalutamide+ADT) or placebo+ADT. The data indicate that the GC score and basal-luminal subtype derived from archived tumor specimens may be biomarkers of response to apalutamide+ADT in the nmCRPC setting. Higher-risk and luminal subtypes appeared to benefit most, although overall, the addition of apalutamide to ADT was beneficial. The data demonstrate that obtaining GC scores may be beneficial for distinguishing individuals for early treatment intensification with apalutamide, and basal-luminal subtyping may be a useful approach for patient selection for further treatment intensification in trials combining novel therapies with apalutamide.