Australian clinical-stage radiopharmaceutical company Clarity Pharmaceuticals Ltd (ASX: CU6) said on Thursday the US Food and Drug Administration (FDA) has granted Breakthrough Therapy designation to 64Cu-SAR-bisPSMA for PET imaging of PSMA-positive lesions in men with prostate cancer and suspected recurrence based on elevated PSA levels.

The designation is intended to accelerate development and regulatory review and was supported by data from the Phase II Co-PSMA trial, the Phase I/II COBRA trial and real-world evidence, which Clarity said demonstrated improved diagnostic performance versus standard-of-care PSMA PET imaging in patients with biochemical recurrence.

In the Co-PSMA trial, which enrolled 50 patients with a median PSA level of 0.43ng/mL, 64Cu-SAR-bisPSMA achieved a patient-level detection rate of 78%, compared with 36% for 68Ga-PSMA-11, and identified 63 lesions versus 24 for the comparator.

The COBRA study enrolled 52 patients with biochemical recurrence whose standard-of-care imaging was negative or equivocal and found 64Cu-SAR-bisPSMA to be safe and effective in detecting recurrent disease, with lesion detection improving on next-day imaging compared with same-day scans.

Clarity said the longer half-life of copper-64 enables imaging up to 30 hours after injection and underpins its SAR-bisPSMA platform, which combines copper-based imaging and therapeutic isotopes.

Clarity is advancing two registrational Phase III studies, AMPLIFY and CLARIFY, both of which have completed recruitment and are in follow-up, with topline results expected in the first half of 2027. The company plans to use the studies to support a future FDA submission seeking approval of 64Cu-SAR-bisPSMA as a diagnostic imaging agent for prostate cancer patients before definitive treatment and for those with biochemical recurrence.