We explored the hypothesis that triple-negative breast cancers with high HRD scores (cohort A) or any solid tumor with germline or somatic mutations in HRD-associated genes other than BRCA1 and BRCA2 (cohort B) could be used to select patients for talazoparib monotherapy in the Talazoparib Beyond BRCA phase II clinical trial. This evidence concerns the gene BRCA2 and triple-negative breast carcinoma.