64Cu-SAR-bisPSMA shows superior prostate cancer detection vs 68Ga-PSMA-11 PET/CT

The phase 2 Co-PSMA (NCT06907641) trial has met its primary end point, showing that ⁶⁴Cu-SAR-bisPSMA was able to detect statistically significantly more prostate-specific membrane antigen (PSMA)-positive prostate cancer lesions compared with standard of care (SOC) ⁶⁸Ga-PSMA-11 PET/CT in patients with low prostate-specific antigen (PSA) levels, Clarity Pharmaceuticals announced in a news release.¹

The investigator-initiated trial is led by Prof Louise Emmett at St Vincent’s Hospital Sydney, Australia. According to Clarity, full results from the study are expected to be shared at an upcoming international conference.

"Achieving the primary end point in the Co-PSMA trial, which was a head-to-head trial against a SOC competing product, is yet another important step in the development of ⁶⁴Cu-SAR-bisPSMA as we look to further validate this agent as best-in-class through 2 registrational trials with 2 Fast Track Designations (FTDs) under our belt for diagnostic applications and a strong focus on commercialization,” said Alan Taylor, PhD, Executive Chairperson of Clarity Pharmaceuticals, in the news release.¹

The trial is specifically comparing the performance of ⁶⁴Cu-SAR-bisPSMA vs SOC ⁶⁸Ga-PSMA-11 PET/CT in detecting prostate cancer recurrence following radical prostatectomy.

⁶⁸Ga-PSMA-11 was approved by the FDA for PET imaging of prostate-specific membrane antigen (PSMA)-positive lesions in men with prostate cancer in December 2020. ⁶⁴Cu-SAR-bisPSMA is an investigational agent that was granted FTDs in August 2024 and January 2025 for PET imaging of patients with suspected metastasis and for biochemical recurrence of prostate cancer, respectively.^2,3

In total, the prospective, open-label, phase 2 Co-PSMA study enrolled 50 patients with biochemical recurrence of prostate cancer who were being considered for curative salvage radiotherapy. To be eligible for enrollment, patients needed to have had radical prostatectomy with no salvage therapy and a PSA level between 0.2 ng/mL and 0.75 ng/mL.

Patients in the study will undergo 3 visits: SOC ⁶⁸Ga-PSMA-11 dose and PET/CT scan, ⁶⁴Cu-SAR-bisPSMA dose and PET/CT scan, and ⁶⁴Cu-SAR-bisPSMA PET/CT only.⁴

The primary end point for the study is to compare the detection rate of sites of prostate cancer recurrence (measured by the number of lesions per patient) between the 2 agents. Secondary outcome measures include comparisons of the diagnostic accuracy of each agent, the detection of lesions outside the prostatic fossa per patient, the magnitude of clinical management change, the total number of lesions between 1 to 4 hours and 24-hour ⁶⁴Cu-SAR-bisPSMA PET/CT imaging timepoints, the frequency of prostatic fossa recurrence, and PSA responses following salvage radiotherapy.

Final completion of the study is expected in November 2025.

In addition to Co-PSMA, ⁶⁴Cu-SAR-bisPSMA is also being assessed in the phase 3 CLARIFY trial in patients with prostate cancer prior to radical prostatectomy and in the phase 3 AMPLIFY trial in patients with a rising or detectable PSA level following initial definitive treatment.

Taylor added in the news release, "We look forward to continuing to work with Prof Emmett, a world-renowned thought leader in the radiopharmaceutical space, in our home city of Sydney on progressing clinical development of the ⁶⁴Cu-SAR-bisPSMA product, including our CLARIFY and AMPLIFY phase III trials. This partnership will ensure we continue to generate the highest quality of data supporting our New Drug Applications (NDAs) to the US Food and Drug Administration (FDA) as the next step towards our mutual goal of improving treatment outcomes for men with prostate cancer."

REFERENCES

1. Co-PSMA trial achieves primary endpoint. News release. Clarity Pharmaceuticals. October 14, 2025. Accessed October 14, 2025. https://www.prnewswire.com/news-releases/co-psma-trial-achieves-primary-endpoint-302582639.html

2. Clarity receives FDA Fast Track Designation for 64Cu-SAR-bisPSMA. News release. Clarity Pharmaceuticals. August 22, 2024. Accessed October 14, 2025. https://www.claritypharmaceuticals.com/news/fast-track/

3. Clarity receives U.S. FDA Fast Track Designation for Cu-64 SAR-bisPSMA in biochemical recurrence of prostate cancer. News release. January 24, 2025. Accessed October 14, 2025. https://www.claritypharmaceuticals.com/news/ftd-2/

4. Comparative performance of 64Copper [64Cu]-SAR-bis-PSMA vs 68Ga PSMA-11 PET CT for the detection of prostate cancer recurrence in the setting of biochemical failure following radical prostatectomy (Co-PSMA). ClinicalTrials.gov. Last updated April 2, 2025. Accessed October 14, 2025. https://clinicaltrials.gov/study/NCT06907641