Difluoromethylornithine and High Dose Testosterone With Enzalutamide in Metastatic Castration-Resistant Prostate Cancer

Eligible patients are those with mCRPC who have progressive disease after treatment with Abiraterone (Abi) used as treatment for castration-sensitive or castration-resistant disease. Patients will continue on androgen deprivation therapy (ADT) with luteinizing hormone-releasing hormone (LHRH) agonist (i.e. Zoladex, Trelstar, Eligard, or Lupron) or LHRH antagonist (Degarelix or Relugolix) if not surgically castrated throughout the duration of the study to inhibit endogenous testosterone production. One cycle of treatment will be 119 days and will involve: 1. 7 days of DFMO at a dose of 1000 mg PO BID (D1-D7), followed by 2. 56 days of combined testosterone and DFMO (testosterone cypionate 400 mg IM on D8 and D36 with continued DFMO 1000 mg PO BID) (D8-D63), followed by 3. 56 days of enzalutamide (enzalutamide 160 mg PO daily) (D64-D119) Patients will receive repeat cycles of treatment until clinical or radiographic progression or toxicity requiring drug cessation.