Supraphysiological Androgen to Enhance Treatment Activity in Metastatic Castration-Resistant Prostate Cancer, SPECTRA Study

OUTLINE: Patients are assigned based on personal preference to 1 of 3 cohorts. COHORT I: Patients are then assigned to 1 of 3 sub-cohorts within cohort I. COHORT Ia: Patients continue to receive ADT and receive testosterone cypionate intramuscularly (IM) on day 1 of cycle 1. Patients then receive testosterone cypionate IM and carboplatin intravenously (IV) on day 1 of subsequent cycles. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. COHORT Ib: Patients continue to receive ADT and receive carboplatin IV on day 1 of cycle 1. Patients then receive testosterone cypionate IM and carboplatin IV on day 1 of subsequent cycles. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. COHORT Ic: Patients continue to receive ADT and receive testosterone cypionate IM and carboplatin IV on day 1 of cycle 1. Patients then receive testosterone cypionate IM and carboplatin IV on day 1 of subsequent cycles. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. COHORT II: Patients are then assigned to 1 of 3 sub-cohorts within cohort II. COHORT IIa: Patients continue to receive ADT and receive testosterone cypionate IM on day 1 of cycle 1. Patients then receive testosterone cypionate IM on day 1 and etoposide orally (PO) once daily (QD) on days 1-14 of subsequent cycles. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. COHORT IIb: Patients continue to receive ADT and receive etoposide PO QD on days 1-14 of cycle 1. Patients then receive testosterone cypionate IM on day 1 and etoposide PO QD on days 1-14 of subsequent cycles. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. COHORT IIc: Patients continue to receive ADT and receive testosterone cypionate IM on day 1 and etoposide PO QD on days 1-14 of cycle 1. Patients then receive testosterone cypionate IM on day 1 and etoposide PO QD on days 1-14 of subsequent cycles. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. COHORT III: Patients are assigned to 1 of 3 sub-cohorts within cohort III. COHORT IIIa: Patients continue to receive ADT and receive testosterone cypionate intramuscularly (IM) on day 1 of cycles 1-6. Patients receive LuPSMA IV on day 1 of cycles 2-6. Cycles repeat every 6 weeks for up to 6 cycles in the absence of disease progression or unacceptable toxicity. Patients then receive testosterone cypionate intramuscularly (IM) on day 1 of subsequent cycles. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. Patients also undergo 68Ga-PSMA positron emission tomography (PET) at screening and single photon emission computed tomography (SPECT)/CT throughout the study. COHORT IIIb: Patients continue to receive ADT and LuPSMA IV on day 1 of cycles 1-6. Patients also receive receive testosterone cypionate IM on day 1 of cycles 2-6 . Cycles repeat every 6 weeks for up to 6 cycles in the absence of disease progression or unacceptable toxicity. Patients receive testosterone cypionate IM on day 1 of subsequent cycles. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. Patients also undergo 68Ga-PSMA PET at screening and single SPECT/CT throughout the study. COHORT IIIc: Patients continue to receive ADT and receive testosterone cypionate IM on day 1 and LuPSMA IV on day 1 of cycles 1-6. Cycles repeat every 6 weeks for up to 6 cycles in the absence of disease progression or unacceptable toxicity. Patients then receive testosterone cypionate IM on day 1 of subsequent cycles. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. Patients also undergo 68Ga-PSMA PET at screening and single SPECT/CT throughout the study. All patients undergo a biopsy on study and blood sample collection on study, and bone scans, dual x-ray absorptiometry (DEXA) and computed tomography (CT) scans throughout the trial. Patients may also undergo an optional second biopsy at the end of study treatment. After completion of study treatment, patients are followed up at 30 days, and then every 6 months for 2 years.