This phase II trial tests how well re-treatment with 177Lu-PSMA-617 works in treating patients with prostate cancer that has spread from where it first started (primary site) to other places in the body (metastatic), that continues to grow or spread after the surgical removal of the testes or medical treatment to block androgen production (castration-resistant), and that has shown a favorable response to initial treatment with 177Lu-PSMA-617. 177Lu-PSMA-617 is a radioactive drug. It binds to a protein called prostate specific membrane antigen (PSMA), which is expressed by some types of prostate tumor cells. When 177Lu-PSMA-617 binds to PSMA-expressing tumor cells, it delivers radiation to the cells, which may kill them. Re-treatment with 177Lu-PSMA-617 in patients who had a favorable response to initial 177Lu-PSMA-617 treatment may improve survival outcomes and disease response in patients with metastatic castration-resistant prostate cancer.
Re-Treatment With 177Lu-PSMA-617 Molecular Radiotherapy for Metastatic Castration Resistant Prostate Cancer: A Prospective Phase 2 Trial (RE-LuPSMA STUDY)
PRIMARY OBJECTIVE:
- To assess the treatment efficacy of re-challenge lutetium Lu 177 vipivotide tetraxetan (177Lu-PSMA-617) therapy (for a maximum of 6 additional cycles) in patients with metastatic castration-resistant prostate cancer (mCRPC) who had a favorable response to a prior regimen of 177Lu-PSMA-617 therapy.
SECONDARY OBJECTIVES:
- To determine the safety of re-challenge 177Lu-PSMA-617 therapy by Common Terminology Criteria for Adverse Events (CTCAE), version 5.0.
II. To determine the rate of patients who have a prostate-specific antigen (PSA) response (defined as a PSA decline of ≥ 50% during re-challenge 177Lu-PSMA-617 therapy).
III. To determine biochemical progression-free survival (PFS) according to Prostate Cancer Working Group 3 (PCWG3) guidelines.
IV. To determine overall survival (OS) from the start (cycle 1 day 1) of the first regimen of 177Lu-PSMA-617 therapy.
- To determine OS from the end (day 1 of the final cycle) of the first regimen of 177Lu-PSMA-617 therapy.
VI. To determine radiographic progression-free survival (rPFS) according to Response Evaluation Criteria in PSMA positron emission tomography (PET)/computed tomography (CT) (RECIP) criteria.
VII. To determine the impact of re-challenge 177Lu-PSMA-617 therapy on bone pain level, health-related quality of life, and performance status (Eastern Cooperative Oncology Group [ECOG]) using established standardized questionnaires.
EXPLORATORY OBJECTIVE:
- To determine the dosimetry in organs and tumor lesions of re-challenge 177Lu-PSMA-617 therapy using a 24-hour single-time-point dosimetry protocol.
OUTLINE:
Patients receive 177Lu-PSMA-617 intravenously (IV) on day 1 of each cycle. Treatment repeats every 6 weeks for up to 6 cycles in the absence of disease progression or unacceptable toxicity. Patients also receive gallium Ga 68 gozetotide IV and undergo PET/CT at screening and on study, undergo single photon emission computed tomography (SPECT)/CT on study, and undergo collection of blood samples throughout the trial.
After completion of study treatment, patients are followed up within 8 weeks of their last treatment cycle and then every 3 months for up to a total of 2 years.
