Phase 2a Study of High-Dose Testosterone Followed by Radioligand Therapy in mCRPC

Inclusion Criteria: * Participants must have histologically or cytologically confirmed prostate cancer that has progressed to mCRPC with no grade 2 or above cancer related symptoms. * Participants need to have either PSA or imaging progression at castrate level of serum testosterone (i.e. \<50ng/dl). The definition of PSA progression and the definitions of imaging progression on measurable or non-measurable lesions will be based on the prostate cancer working group 3 (PCWG3) criteria. Patients with symptomatic oligo progression (1-3 sites), the symptoms need to be improved to grade 1 or less with palliative local therapy prior to study enrollment. * Participants need to have a positive PSMA PET scan and deem eligible for PSMA-617. * Allowable prior therapies: Prior treatment with one line of ARPI. Patients need to be on ARPI for at least 4 weeks to be considered one line of therapy. Prior treatment with sipuleucel-T for mCRPC. Prior treatment with docetaxel in the castration sensitive setting. * ECOG performance status 0-1. * Participants must have adequate organ and marrow functions. * Participants with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial. * Participants with h/o myocardial infarction or history of congestive heart failure, need to have estimated left ventricle ejection fraction above 40% either on echocar…