Dr Ravi on the Background and Rationale of the Phase 4 PSMAtrack Study in mHSPC

“We wanted to look at how changes in disease on PSMA-PET [scans] occurred during the initial part of therapy in patients with mHSPC.”

Praful Ravi, MB, BChir, MRCP, the medical director of GU Theranostics and a physician at Dana-Farber Cancer Institute, as well as an assistant professor of medicine at Harvard Medical School, discussed the rationale for and design of the phase 4 PSMAtrack study (NCT06479187) of changes in PSMA-PET scan results during initial therapy in patients with metastatic hormone-sensitive prostate cancer (mHSPC).

Ravi began by explaining that he and his coauthors conducted a prospective pilot study evaluating serial PSMA-PET scans in patients with mHSPC. The study enrolled 21 patients with mHSPC and sought to characterize changes in disease burden detected on PSMA PET during the first 6 months of standard treatment, he continued.

The investigators performed a baseline PSMA-PET scan using piflufolastat F 18 (Pylarify TruVu) either before the initiation of androgen deprivation therapy (ADT) or within 21 days after starting ADT, Ravi said. Patients then received standard-of-care systemic treatment, consisting of either doublet or triplet therapy, without radiotherapy to the primary prostate tumor or metastatic lesions to avoid confounding imaging findings, he said. A second PSMA-PET scan was obtained 6 months after treatment initiation using the same imaging protocol, he noted.

The primary objective of the study was to determine the proportion of patients who continued to have residual PSMA-avid disease on imaging after 6 months of therapy, Ravi said.

Although limited by its small sample size, this prospective pilot study provides an initial framework for evaluating PSMA-PET scans as a response assessment tool in patients with mHSPC. The findings may help inform future research investigating whether persistent PSMA-positive disease after systemic therapy has prognostic significance or could identify patients who may benefit from additional treatment intensification or response-adapted therapeutic strategies.