Clarity Pharmaceuticals (ASX: CU6) Doses 383 Patients in Phase III CLARIFY Trial

Clarity Pharmaceuticals has dosed the planned 383 participants in its Phase III CLARIFY trial, completing a key enrolment step ahead of topline results expected in the first half of calendar 2027.

The registrational study is assessing Clarity’s copper-64 SAR-bisPSMA diagnostic imaging product in patients with untreated, high-risk prostate cancer who are proceeding to prostate removal and pelvic lymph node dissection. It is the company’s first Phase III registrational trial and is being conducted across the US and Australia.

CLARIFY’s results are intended to support a US Food and Drug Administration application for approval of copper-64 SAR-bisPSMA as a prostate cancer imaging agent before definitive therapy. However, the product remains unregistered, and its safety and efficacy have not been assessed by the FDA or Australia’s Therapeutic Goods Administration.

Accuracy under the microscope

The non-randomised, open-label trial will measure the product’s sensitivity and specificity in detecting prostate cancer within pelvic lymph nodes. Imaging results will be compared with histopathology from lymph nodes removed during surgery, providing confirmation of whether suspected lesions were cancerous.

Those endpoints will be assessed separately for scans performed between one and four hours after administration and scans conducted approximately 24 hours later. This will allow Clarity to evaluate both same-day and next-day imaging.

The trial’s design matters because accurately identifying cancer in pelvic lymph nodes can inform treatment decisions. Clarity said approved PSMA PET agents reported sensitivities of 27% to 40% in their respective pivotal Phase III studies for detecting pelvic lymph node metastases before prostatectomy. None reached their prespecified primary sensitivity thresholds, according to the company.

CLARIFY also allows direct comparison with standard-of-care PSMA imaging where those scans were performed.

Two pivotal readouts due in 2027

Topline CLARIFY data are scheduled for release in the first half of 2027 alongside results from AMPLIFY, Clarity’s other registrational Phase III study of copper-64 SAR-bisPSMA. AMPLIFY is evaluating the imaging agent in patients with biochemical recurrence of prostate cancer and has also completed recruitment.

Earlier evidence supporting CLARIFY came from the 30-patient Phase I PROPELLER trial. Clarity reported that same-day copper-64 SAR-bisPSMA imaging achieved approximately 30% greater lesion detection and two to three times higher tracer uptake and contrast than gallium-68 PSMA-11 imaging in the pre-prostatectomy setting.

The company has also observed improved diagnostic performance from next-day imaging compared with same-day imaging in its COBRA and Co-PSMA studies involving biochemical recurrence. Whether that benefit extends to newly diagnosed, high-risk patients is one of the questions CLARIFY is designed to assess.

Copper-64 SAR-bisPSMA combines two PSMA-targeting agents with Clarity’s proprietary sarcophagine technology, which holds the copper isotope within a cage-like chelator. The upcoming Phase III data will determine whether the earlier diagnostic findings translate into the evidence required for a US regulatory submission.