A Trial of CTT1403 for Metastatic Castration Resistant Prostate Cancer

This is a Phase 1, first-in-human dose escalation/dose expansion study evaluating escalating doses of CTT1403 in patients with PSMA-avid mCRPC with progressive disease on at least one androgen signaling inhibitor, followed by a dose expansion to further evaluate the safety, tolerability, efficacy and biological activity of CTT1403. CTT1403 is a PSMA-targeted 177Lu-labeled radiotherapy being developed for prostate cancer with a unique PSMA binding scaffold and an albumin binding moiety to extend circulation half-life. The PSMA binding scaffold is shared with CTT1057, a PSMA-specific PET diagnostic imaging agent shown in Phase 1 clinical trials to be specifically taken up by PSMA+ tumor. PSMA PET imaging by CTT1057 will be used diagnostically to select patients with PSMA-avid disease for treatment. The purpose of this study is to identify the dose limiting toxicity and recommended phase 2 dose of CTT1403. Eligible participants with demonstrated therapeutic benefit will be offered a second dose of study drug.