Enrollment goal met in trial of 64Cu-SAR-bisPSMA vs. 68Ga-PSMA-11 PET/CT

The target enrollment has been reached in the investigator-initiated Co-PSMA trial (NCT06907641), comparing the performance of ⁶⁴Cu-SAR-bisPSMA vs standard-of-care ⁶⁸Ga-PSMA-11 PET/CT in detecting prostate cancer recurrence following radical prostatectomy, Clarity Pharmaceuticals announced in a news release.¹

The study is expected to be completed in November 2025.

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 fast track designations in August 2024 and January 2025 for PET imaging of patients with suspected metastasis and for biochemical recurrence of prostate cancer, respectively.^2,3

“We are pleased to have reached our [enrollment] target for the Co-PSMA trial,” said principal investigator Professor Louise Emmett of St Vincent’s Hospital in Sydney, Australia, in the news release.¹ “If the Co-PSMA trial confirms that ⁶⁴Cu-SAR-bisPSMA can detect more lesions than ⁶⁸Ga-PSMA-11 in this patient group with such low [prostate-specific antigen] PSA, this may improve image-guided therapy, potentially avoiding complications and improving outcomes. We look forward to reporting the trial results in the coming months.”

In total, the prospective, open-label, phase 2 Co-PSMA study enrolled 50 patients with biochemical recurrence of prostate cancer who are 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.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 hours, the frequency of prostatic fossa recurrence, and PSA responses following salvage radiotherapy.

Final completion of the study is expected in November 2025.

Additional Studies of ⁶⁴Cu-SAR-bisPSMA

⁶⁴Cu-SAR-bisPSMA was previously evaluated in the PROPELLER (NCT04839367) and COBRA (NCT05249127) trials, which assessed the agent in the pre-prostatectomy setting and the biochemical recurrence setting, respectively.

Data from the phase 1 PROPELLER trial led to the registrational phase 3 CLARIFY trial (NCT06056830) in patients with prostate cancer prior to radical prostatectomy. Final completion of the CLARIFY trial is expected in December 2025.⁵

Additionally, data from the phase 1/2 COBRA trial led to the start of the ongoing phase 3 AMPLIFY trial (NCT06970847), which launched in May 2025.⁶ Overall, the nonrandomized, single-arm, open-label, multicenter AMPLIFY trial will evaluate the ability of ⁶⁴Cu-SAR-bisPSMA PET/CT to detect prostate cancer lesions among patients with a rising or detectable PSA level following initial definitive treatment. The study plans to enroll approximately 220 patients across clinical trial sites in the US and Australia, with enrollment expected to open soon, according to Clarity Pharmaceuticals. Final completion of the study is expected in December 2026.

REFERENCES

1. Co-PSMA trial: Recruitment successfully completed. News release. Clarity Pharmaceuticals. July 17, 2025. Accessed July 17, 2025. https://www.claritypharmaceuticals.com/news/co-psma-recruitmentcomplete/

2. Clarity receives FDA Fast Track Designation for 64Cu-SAR-bisPSMA. News release. Clarity Pharmaceuticals. August 22, 2024. Accessed July 17, 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 July 17, 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 July 17, 2025. https://clinicaltrials.gov/study/NCT06907641

5. Positron Emission Tomography using 64Cu-SAR-bisPSMA in participants with high-risk prostate cancer prior to radical prostatectomy (CLARIFY). ClinicalTrials.gov. Last updated May 2, 2025. Accessed July 17, 2025. https://clinicaltrials.gov/study/NCT06056830

6. 64Cu-SAR-bisPSMA Positron Emission Tomography: A phase 3 study of participants with biochemical recurrence of prostate cancer (AMPLIFY). ClinicalTrials.gov. Last updated July 17, 2025. Accessed July 17, 2025. https://clinicaltrials.gov/study/NCT06970847