67Cu-SAR-bisPSMA continues to show promise in mCRPC

⁶⁷Cu-SAR-bisPSMA continued to demonstrate encouraging efficacy and a favorable safety profile in patients with prostate-specific membrane antigen (PSMA)-expressing metastatic castration-resistant prostate cancer (mCRPC), according to interim results from the dose expansion phase of the 1/2a SECuRE trial (NCT04868604).¹

After an interim review of the data, the Safety Review Committee (SRC) recommended that the trial proceed with the cohort expansion phase as planned with no modifications to the protocol.

“We have already seen a glimpse of the effects of ⁶⁷Cu-SAR-bisPSMA through our dose escalation cohorts with additional and similar data being generated in the cohort expansion phase, demonstrating once again excellent efficacy and safety results of ⁶⁷Cu-SAR-bisPSMA,” said Clarity’s executive chairperson, Alan Taylor, PhD, in a news release from the company.¹

The interim analysis of the trial included 9 participants who had evaluable data by the cutoff of November 25, 2025. The majority of these patients (66.7%) had bone metastasis at the time of enrollment, and over half (55.6%) had received more than 5 previous anti-cancer regimens. Patients had not received previous chemotherapy in the mCRPC setting. For the study, 7 participants received 8 GBq ⁶⁷Cu-SAR-bisPSMA alone and 2 participants received 8 GBq ⁶⁷Cu-SAR-bisPSMA in combination with enzalutamide (Xtandi).

By data cutoff, 6 of the 9 participants had at least 2 prostate-specific antigen (PSA) results following ⁶⁷Cu-SAR-bisPSMA treatment. Of these 6 patients, 66.7% (4 of 6) achieved a PSA reduction of at least 50%, and 33.3% of patients (2 of 6) achieved a PSA reduction of at least 80%.

One patient who presented with bone metastasis at the time of enrollment achieved undetectable levels of PSA and no metastatic disease on CT or bone scan following treatment. The patient experienced only grade 1 adverse events (AEs), most of which were gastrointestinal events. No hematological or renal AEs were observed. According to Clarity Pharmaceuticals, “The participant reported having excellent quality of life following the treatment.”

The safety profile for ⁶⁷Cu-SAR-bisPSMA in the overall population was also favorable, with the majority of related AEs being grade 1 or 2. The most common related AEs were nausea and lymphopenia, which were reported in 33.3% of patients (3 of 9) each. No new AEs related to ⁶⁷Cu-SAR-bisPSMA have been observed in the combination arm.

Based on results from the trial to date, investigators will continue to enroll patients into the dose expansion phase. The target enrollment is 24 participants, with recruitment expected to reach completion in 2026.

Overall, SECuRE is a phase 1/2a theranostic trial of ⁶⁴Cu/⁶⁷Cu-SAR-bisPSMA. In the study, “⁶⁴Cu-SAR-bisPSMA is used to visualize PSMA-expressing lesions and select candidates for subsequent ⁶⁷Cu-SAR-bisPSMA therapy,” according to Clarity. Data from the dose escalation phase showed promising efficacy and safety with ⁶⁷Cu-SAR-bisPSMA and supported progression to the dose expansion phase at the dose level of 8 GBq.

Results from the dose expansion cohorts are intended to support progression to a phase 3 registrational trial of ⁶⁷Cu-SAR-bisPSMA in mCRPC.

“Importantly, the work we have undertaken during the dose escalation phase is now continuing to provide a strong foundation for us as we look ahead at protocol development and dosing for our Phase 3 clinical trial and commercialization,” Taylor concluded in the news release.¹ “As the participant numbers continue to increase with the trial enrollment, we continue to see very promising responses over and over again, giving us more confidence about the future of this product and its potential for commercialization in mCRPC.”

REFERENCE

1. SECuRE trial to continue with no modifications to protocol following Safety Review Committee meeting. News release. Clarity Pharmaceuticals. January 15, 2026. Accessed January 15, 2026. https://www.claritypharmaceuticals.com/news/secure-src/