Preliminary results promising for 64Cu SAR-Bombesin in prostate cancer

The novel imaging agent ⁶⁴Cu SAR-Bombesin showed promising efficacy and safety in patients with prostate cancer, according to preliminary findings from the phase 2 BOP trial (NCT05613842) presented at the European Association of Nuclear Medicine (EANM) 2023 Congress.¹

“What is most exciting about this data is the identification of lesions in the most difficult to treat patient group, who are negative on all other standard of care imaging,” said Dr. Alan Taylor, executive chairman of Clarity, the developer of 64Cu SAR-Bombesin.

⁶⁴Cu SAR-Bombesin targets the Gastrin Releasing Peptide receptor (GRPr), which is found on prostate tumors as well as several other tumors.¹

The BOP trial specifically explored ⁶⁴Cu SAR-Bombesin in 2 groups of patients: men with suspected biochemical recurrence (BCR) of their prostate cancer whose PSMA-PET imaging scans are negative or show low PSMA expression; and men with metastatic castration-resistant prostate cancer who are ineligible to receive PSMA therapy.

At study entry, 96% of patients in the BCR cohort had received radical prostatectomy, with a mean PSA of 0.69 ng/ml (range, 0.28 – 2.45) and an average PSA doubling time of 4.2 months (range, 2.8 – 7.5).¹

All patients were treated with ⁶⁴Cu SAR-Bombesin at the mean dose of 210 MBq. Patients received PET imaging at 1, 3, and 24 hours following administration of ⁶⁴Cu SAR-Bombesin.¹

According to the study results shared at the EANM congress, ^“64Cu SAR-Bombesin PET avid disease /was identified in”32% of patients (8/25) whose standard of care PSMA PET imaging had been negative or equivocal.¹

Regarding safety, the administration of ⁶⁴Cu SAR-Bombesin was not shown to cause any adverse events.

“We are pleased with the results we have generated in the BOP trial, which have shown that ⁶⁴Cu SAR-Bombesin can detect lesions in men with biochemically recurrent prostate cancer that are negative or equivocal on PSMA PET. We believe SAR- Bombesin has the potential to add value in biochemical recurrence of prostate cancer following definitive therapy. We look forward to continuing our collaboration with Clarity and also exploring the diagnostic and therapeutic benefits of SAR-Bombesin in not only prostate cancer which is PSMA negative, but also in other diseases such as breast cancer,” Louise Emmett, MBChB, FRACP, MD, St Vincent’s Hospital Sydney, principal investigator for the BOP trial, stated in a press release.¹

Also commenting in the press release, Dr. Alan Taylor, executive chairman of Clarity, the developer of ⁶⁴Cu SAR-Bombesin, stated, “What is most exciting about this data is the identification of lesions in the most difficult to treat patient group, who are negative on all other standard of care imaging. This information arms clinicians with accurate diagnostic information and helps them determine the best course of treatment for their patients. In essence, for the patients that have had a positive SAR-Bombesin scan, this is the difference between having an incorrect negative cancer diagnosis leading to cancer progression and now having an effective treatment plan that may lead to long term remission. This patient-centric approach, reinforced by the flexibility in the timing of the scan, centralized product manufacture and its broad distribution to any imaging center with a PET camera, would be a true paradigm shift in the management of prostate cancer. We are continuing to work diligently on the development of the SAR-Bombesin product in the US, including our phase 2 SABRE trial (NCT05407311) as well as the theranostic phase 2/2a COMBAT trial (NCT05633160), in order to make this product available to the patients who need it most and might not have any other diagnostic and therapeutic options available to them.”¹

Reference

1. BOP preliminary trial results presented at EANM 2023 conference. Clarity Pharmaceuticals. Accessed September 14, 2023. https://www.claritypharmaceuticals.com/news/bopeanm2023/