The proposed diagnostic agent has a long half-life, enables imaging the next day, and correlates to a longer shelf life in the pharmacy.
The FDA granted fast track designation to 64Cu-SAR-bisPSMA (Clarity Pharmaceuticals) for positron emission tomography (PET) imaging for prostate-specific membrane antigen positive prostate cancer lesions. This will help identify individuals with suspected metastasis who are candidates for initial definitive therapy.1
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“Receiving fast track designation for 64Cu-SAR-bisPSMA is a significant milestone, especially as we are actively recruiting into our first registrational phase 3 trial, CLARIFY, and preparing for an end of phase meeting with the FDA for a second pivotal phase 3 trial with this product,” Alan Taylor, executive chairperson for Clarity, said in a news release. “The designation will allow us to work closely with the FDA to facilitate the development process, potentially accelerating the approval of this best-in-class diagnostic."1
Currently, there are trials for 2 indications for 64Cu-SAR-bisPSMA, including patients with prostate cancer prior to undergoing radical prostatectomy and patients with prostate cancer with biochemical recurrence of their disease. The phase 1 PROPELLER (NCT048393671) study showed that the drug was safe and well tolerated in 30 individuals, with only 1 reporting a metallic taste (grade 1). It also established the optimal dose of 200 MBq, with reader 1 detecting 100% of prostate cancer in individuals and Reader 2 detecting prostate cancer in 85.7% of patients, compared with 77.8% and 83.3% for 68Ga PSMA-11.1,2
In the phase 1/2 COBRA (NCT05249127) trial, there was only 1 adverse event (grade 2 worsening of type 2 diabetes), according to the study authors. The diagnostic resulted in identification of lesions in up to 80% of individuals, with more lesions and patients positively scanned on next-day imaging.3
"We believe that 64Cu-SAR-bisPSMA could be a game changer in prostate cancer diagnosis. Due to its dual targeting structure, bisPSMA, and the longer half-life of copper-64, enabling next-day imaging, this unique product has shown higher tumor uptake and retention and exhibited a capability of detecting much smaller lesions,” Taylor said in the news release. “The longer half-life of the isotope also translates into a longer shelf-life than currently used diagnostic radiopharmaceuticals, allowing for centralized manufacture and wider distribution, while also supporting flexible patient scheduling. These features are not available with gallium-68 and fluorine-18 based diagnostics.”1
Trial Name: Positron Emission Tomography Using 64Cu-SAR-bisPSMA in Participants With High-risk Prostate Cancer Prior to Radical Prostatectomy (CLARIFY)
ClinicalTrials.gov ID: NCT06056830
Sponsor: Clarity Pharmaceuticals Ltd
Completion Date (Estimated): February 2025
To further investigate the drug, the company launched the phase 3 CLARIFY (NCT06056830) study, which will assess the diagnostic performance in detecting regional nodal metastasis in individuals with high-risk prostate cancer prior to radical prostatectomy. There will be 2 days of imaging, with one on the day of administration and one approximately 24 hours after administration. The first patient of the trial was dosed in December 2023 and will include 383 patients. The final results of the study are intended to be submitted to the FDA for approval of the drug as a new diagnostic imaging agent.4,5
