This is an unblinded, three cohort phase II study evaluating the efficacy of high dose testosterone (BAT) for patients with mCRPC and inactivating mutations in ATM, CDK12 or CHEK2. Patients will receive BAT until disease progression or intolerance, whichever occurs first. Throughout the study, safety and tolerability will be assessed by frequent recording of adverse events, vital signs and safety laboratory assessments. Progression will be evaluated with bone scan, CT of the abdomen/pelvis and PSA as per PCWG3 criteria.
This study will determine whether the presence of DNA repair deficiency in the form of alterations in the genes ATM, CDK12 or CHEK2 predicts for a high likelihood of responding to the use of intermittent high dose testosterone. This therapy may result in responses in tumors which are genetically unstable because of DNA repair deficiency and this is a prospective study to test that hypothesis