Study launches of Cu-64 SAR-bisPSMA in biochemically recurrent prostate cancer


The phase 1/2 COBRA trial exploring 64Cu SAR-bisPSMA in patients with biochemical recurrence (BCR) of prostate cancer following definitive therapy is now open for enrollment, according to Clarity Pharmaceuticals, the manufacturer of the novel PSMA-PET imaging agent.1

Eligible patients for the multicenter, nonrandomized, single-arm trial (NCT05249127) will have suspected recurrence of prostate cancer as determined by a rising prostate-specific antigen (PSA) following definitive therapy.2 Among patients who received radical prostatectomy, eligibility is defined as detectable or rising PSA ≥ 0.2 ng/mL with a confirmatory PSA ≥ 0.2 ng/mL. For patients who received radiation, cryotherapy, or brachytherapy, those eligible will have a PSA level elevated by ≥2 ng/mL above the nadir per the ASTRO Phoenix definition of biochemical failure.

The targeted enrollment for the trial is 50 patients. The ability of 64Cu SAR-bisPSMA to detect prostate cancer recurrence, as well as its safety and tolerability, are the primary end points of the study. The estimated primary completion is April 2023.

Neal Shore, MD

Neal Shore, MD

"We are very excited to initiate patient accrual for the COBRA trial which will explore and validate the clinical benefits associated with the novel SAR-bisPSMA agent. The preliminary data from Clarity's SECURE and PROPELLER trials as well as preclinical data, indicate high uptake of Copper-64 SAR-bisPSMA, which suggests improved prostate cancer detection, inclusive of very low volume disease, which is especially important for patients with suspected disease recurrence,” Neal Shore MD, FACS, lead principal investigator of the COBRA trial and CMO – Urology/Surgical Oncology, GenesisCare, US and the Medical Director of Carolina Urologic Research Centre, stated in a press release.

“Importantly, the logistical advantages of central manufacture and the on-demand delivery of this novel imaging agent will provide enhanced accessibility to treatment facilities in the United States. I look forward to expanding the trial U.S. sites and generating additional data for this next-generation technology which could ensure both ease of access and improved diagnostic accuracy for BCR patients," added Shore.

Other trials of 64Cu SAR-bisPSMA

There are several other ongoing trials exploring 64Cu SAR-bisPSMA, including the prospective, nonrandomized, single-arm, single-center, open-label phase 1/2 X-Calibur trial (NCT05286840)3, which is recruiting 150 patients with known or suspected prostate cancer. The primary outcome measure of the study is safety. Secondary outcome measures include disease status adjustment, disease staging adjustment, and clinical management plan prior to and following 64Cu SAR-bisPSMA PET/CT Imaging.

Additionally, the phase 1/2 SECURE trial (NCT04868604)4 is examining the novel PSMA theranostic 64/67Cu SAR-bisPSMA in patients with metastatic castration-resistant prostate cancer. The theranostic 64/67Cu SAR-bisPSMA combines 64Cu SAR-bisPSMA and the PSMA targeted therapy 67Cu SAR-bisPSMA.

In the open-label, single-arm, dose-escalation study, 64Cu SAR-bisPSMA will be used for the selection of appropriate patients to receive treatment with 67Cu SAR-bis-PSMA. The study aims to enroll 44 patients at multiple locations in the United States.


1. Clarity's US-based Cu-64 SAR-bisPSMA trial in prostate cancer opens for recruitment. Published online March 28, 2022. Accessed April 1, 2022.

2. NIH 64Cu-SAR-bisPSMA for Identification of Participants With Recurrence of Prostate Cancer (COBRA). Last updated February 23, 2022. Accessed April 1, 2022.

3. New clinical trial collaboration for Cu-64 SAR-bisPSMA in prostate cancer. Published online and accessed March 24, 2022.

4. NIH 64Cu-SAR-bisPSMA and 67Cu-SAR-bisPSMA for Identification and Treatment of PSMA-expressing Metastatic Castrate Resistant Prostate Cancer (SECURE). Last updated November 5, 2021. Accessed March 24, 2022.

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