Pilot randomized study uses bicalutamide androgen-receptor inhibitor to modulate PSMA imaging signal

Washington University School of Medicine is running this randomized, open-label pilot study to test whether a short course of bicalutamide (a nonsteroidal androgen receptor inhibitor) alters PSMA expression enough to improve lesion detectability on PSMA PET/CT in biochemical recurrence at very low PSA (<1.0 ng/mL). Adults with biochemically recurrent, intermediate unfavorable/high-risk prostate cancer after prostatectomy and/or around salvage radiotherapy are randomized 1:1 to either one baseline PET/CT (Group A) or baseline plus a second PET/CT after ~2 weeks of bicalutamide (Group B). Both arms use 18F-rhPSMA-7.3 (flotufolastat F 18; Posluma), a PSMA-targeted PET radiotracer originally developed by Blue Earth Diagnostics (now part of Bracco), with standardized early and ~60-minute imaging plus blood draws including PROSTest and PSA. The scientific angle is “hormonal priming” for imaging—trying to increase (or otherwise predictably shift) PSMA signal at PSA levels where localization is often hardest yet most actionable for planning salvage treatment. Today’s care for PSA recurrence after prostatectomy is risk-adapted salvage radiotherapy to the prostate bed ± pelvic nodes, often with short-course androgen deprivation/antiandrogen therapy, with PSMA PET increasingly used to tailor fields and add metastasis-directed radiation when lesions are found.