(UroToday.com) PARP inhibitors are approved for patients with metastatic prostate cancer and mutations in certain DNA-repair associated genes, such as ATM and BRCA2. ATM mutations have been included in a list of actionable mutations for PARP inhibitor therapeutic trials, however, despite preclinical evidence, PARP inhibitors have shown minimal clinical activity in ATM mutant prostate cancer. At the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting, Dr. Charles Ryan and colleagues presented the results of their study exploring co-occurring genomic alterations that may drive outcomes of metastatic prostate cancer patients with tumors harboring ATM mutations and provide clues for understanding therapy resistance and potential targets.