Trial of 64Cu SAR-bisPSMA in biochemically recurrent prostate cancer hits enrollment goal

The recruitment target has been met in the phase 1/2 COBRA trial (NCT05249127) exploring ⁶⁴Cu SAR-bisPSMA in patients with biochemical recurrence (BCR) of prostate cancer following definitive therapy, according to Clarity Pharmaceuticals, the manufacturer of the novel PSMA-PET imaging agent.¹

“COBRA is our second diagnostic trial of SAR-bisPSMA in prostate cancer. It reaches its recruitment target shortly after receiving positive top-line results in our PROPELLER trial,” said Dr. Alan Taylor, executive chairman, Clarity.

The enrollment goal of 50 patients has been achieved. The multicenter, nonrandomized, single-arm trial is enrolling patients with suspected recurrence of prostate cancer as determined by a rising 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 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.

"We are very pleased to have reached our recruitment target for the COBRA trial. The data generated thus far on the SAR-bisPSMA product is very encouraging and shows high uptake of the agent by prostate cancer cells. The high uptake of product and the ability to image the patients at later timepoints adds both patient and clinic flexibility for locating and visualizing even low volume tumors, a unique feature of this imaging technology,” Neal Shore MD, lead principal investigator in the COBRA trial and CMO – Urology/Surgical Oncology, GenesisCare, US and the Medical Director of Carolina Urologic Research Centre, stated in a news release.

“It is important for improving prostate cancer recurrence detection where the cancer burden may be quite low and thus identifying the specific location provides clinically important implications for the patients' therapeutic selection. We look forward to analyzing the COBRA trial data and advancing the clinical development of SAR-bisPSMA together with Clarity," added Shore.

Also commenting in the news release, Dr. Alan Taylor, executive chairman, Clarity, stated, “COBRA is our second diagnostic trial of SAR-bisPSMA in prostate cancer. It reaches its recruitment target shortly after receiving positive top-line results in our PROPELLER trial.³ Running 2 trials with this product is in line with advice received from the US FDA to address the 2 relevant patient populations for registration of ⁶⁴Cu SAR-bisPSMA: in pre-prostatectomy/pre-definitive treatment of patients with confirmed prostate cancer (PROPELLER trial); and in patients with suspected BCR of prostate cancer (COBRA trial). We look forward to analyzing the data from the COBRA trial with a view to initiating a phase 3 trial in this patient population."

References

1. US based COBRA diagnostic prostate cancer trial reaches recruitment target. Published online and accessed February 9, 2023. https://prn.to/3JVVrV3

2. NIH ClinicalTrials.gov. 64Cu-SAR-bisPSMA for Identification of Participants With Recurrence of Prostate Cancer (COBRA). Last updated February 23, 2022. Accessed April 1, 2022. https://clinicaltrials.gov/ct2/show/NCT05249127.

3. Positive topline results from Clarity’s PROPELLER SAR-bisPSMA prostate cancer diagnostic trial. Published online December 14, 2022. Accessed December 15, 2022. https://www.claritypharmaceuticals.com/news/propeller_topline.