Clarity Pharmaceuticals gains FDA fast-track status for advanced prostate cancer imaging drug

Oncology specialist Clarity Pharmaceuticals (ASX: CU6) has been granted fast-track designation by the US Food and Drug Administration (FDA) for the use of its 64Cu-SAR-bisPSMA in positron emission tomography imaging for prostate cancer.

SAR-bisPSMA – a next-generation theranostic radiopharmaceutical with dual prostate-specific membrane antigen (PSMA)-targeting agents linked to Clarity’s SAR chelator technology – utilises copper isotopes for imaging and therapy for patients with positive prostate cancer lesions and suspected metastasis.

PSMA is a protein expressed in more than 87% of patients and is believed to be a valuable diagnostic and therapeutic target.

Expedited review

The FDA designation is expected to expedite the development of the drug and pave the way for a potentially faster review process once Clarity submits a product approval application.

The company is allowed to submit sections of the application as they are ready, rather than waiting for the entire package to be completed before lodging it.

The designation will also enable more frequent communication with the FDA, allowing for the rapid resolution of queries during development and reducing the review period needed to bring the product to market.

It could also potentially shorten the period of diagnosis and treatment planning for patients.

‘Timely achievement’

Clarity executive chair Dr Alan Taylor said the designation was a timely achievement in SAR-bisPSMA’s development.

“This is a significant milestone for us as we continue the recruitment of candidates for our ongoing Phase III trial Clarify and prepare for an end-of-phase meeting with the FDA for a second pivotal Phase III trial with this product,” he said.

“The designation will allow us to work closely with the regulator to facilitate the development process, potentially accelerating the approval of this best-in-class diagnostic.”

Prostate cancer trials

Clarity’s ongoing clinical program with SAR-bisPSMA includes a trial with prostate cancer patients prior to undergoing radical prostatectomy and another with candidates who have a biochemical recurrence (BCR) of their disease.

The company has already completed a Phase I Propellor study, which demonstrated favourable safety and efficacy results in patients with prostate cancer prior to radical prostatectomy.

Clarity has since commenced the Phase III Clarify trial, in parallel with a Phase I/II Cobra trial, which found SAR-bisPSMA highly-effective in detecting prostate cancer lesions in patients with BCR compared to existing diagnostics.

Dual-targeting structure

“We believe this drug could be a game-changer in prostate cancer diagnosis due to the dual-targeting bisPSMA structure and the longer half-life of copper-64, which can enable next-day imaging,” Dr Taylor said.

“The longer half-life of the isotope also translates into a longer shelf-life than current gallium-68 and fluorine-18-based diagnostic radiopharmaceuticals, allowing for centralised manufacture and wider distribution while supporting flexible patient scheduling.”

Dr Taylor said Clarity hoped to address the critical need for more accurate and accessible diagnostic tools in prostate cancer management.

High unmet need

Prostate cancer is the second most common cancer in males and the fifth leading cause of death in men worldwide.

Patients diagnosed at later stages have poor treatment outcomes, indicating a high unmet need for early detection and better treatment options for metastatic castration-resistant prostate cancer.

“This FDA designation highlights the potential of 64Cu-SAR-bisPSMA to provide a novel diagnostic option for patients with prostate cancer and address the limitations of current-generation diagnostic radiopharmaceuticals,” Dr Taylor said.