A clinical trial led by Professor Louise Emmett at St Vincent’s Hospital, Sydney, has achieved its primary endpoint, showing that 64Cu-SAR-bisPSMA detects significantly more prostate cancer lesions than the current standard-of-care PSMA PET imaging in men with low PSA levels.
The Phase 2 study, known as Co-PSMA, compared Clarity Pharmaceuticals’ (ASX:CU6) novel copper-64 labelled agent against 68Ga-PSMA-11 PET/CT. It enrolled 50 men with biochemical recurrence after radical prostatectomy, with PSA levels between 0.2 and 0.75 ng/mL. All participants were candidates for curative salvage therapy — a clinical setting where early and accurate detection of disease recurrence is crucial.
The trial met its primary endpoint, confirming that 64Cu-SAR-bisPSMA PET/CT identified a significantly higher number of PSMA-positive lesions per patient than the standard 68Ga-PSMA-11 scan. This improved sensitivity at very low PSA levels is particularly important: detecting lesions earlier and more accurately can influence salvage treatment decisions and potentially improve long-term outcomes for patients.
Complete data from the study are now being analysed and will be presented at an upcoming international medical conference.
The topline Co-PSMA findings align with results from the earlier COBRA trial, which evaluated 64Cu-SAR-bisPSMA in patients whose standard PSMA PET scans were negative or equivocal. In COBRA, 70 per cent of patients had a positive scan using 64Cu-SAR-bisPSMA on the same day, increasing to 90 per cent on next-day imaging, compared to only 60 per cent for standard PSMA PET.
“This is yet another important step in the development of 64Cu-SAR-bisPSMA,” said Dr Alan Taylor, Executive Chairperson of Clarity Pharmaceuticals.
He noted that the head-to-head win against a standard competing product reinforces the company’s strategy to establish 64Cu-SAR-bisPSMA as a best-in-class diagnostic agent. “With two registrational trials underway and two Fast Track Designations for diagnostic applications, our focus is firmly on bringing this product to patients and the market.”
Dr Taylor also highlighted the commercial potential: the US PSMA PET imaging market is valued at around US$2 billion annually and is expected to exceed US$3 billion by 2029. “The current market is dominated by low-sensitivity agents. We believe 64Cu-SAR-bisPSMA can set a new standard of care, expanding the market by enabling earlier detection,” he said.