Collaboration to support phase 3 SECuRE trial of 67Cu-SAR-bisPSMA

Clarity Pharmaceuticals has entered into an MSA and Clinical Manufacturing Agreement with Nucleus RadioPharma to support the development and manufacturing of ⁶⁷Cu-SAR-bisPSMA for the ongoing phase 3 SECuRE trial (NCT04868604) in metastatic castration-resistant prostate cancer (mCRPC), Clarity announced in a news release.¹

Final completion of the study is anticipated for September 2026.

The agreement went into effect on November 8, 2024, and will remain in effect for an initial period of 36 months thereafter.

“We continue to strengthen our manufacturing network, ensuring prostate cancer patients in need of novel radiopharmaceutical treatments can get access to what we believe is a best-in-class product, on time and on demand,” said Clarity’s executive chairperson, Alan Taylor, PhD, in the news release.¹ “We have seen excellent data from the SECuRE trial and in case studies as part of the U.S. Food and Drug Administration (FDA) Expanded Access Program (EAP) with ⁶⁷Cu-SAR-bisPSMA and look forward to progressing the development of this important therapy to address the large unmet need in prostate cancer care.”

This announcement follows a recent update from Clarity last month, in which they reported that the third participant in cohort 4 of the SECuRE trial completed the dose limiting toxicity period.² This patient, as well as the other patients in cohort 4 of the trial, received 2 doses of 12 GBq of ⁶⁷Cu-SAR-bisPSMA.

In September, the company reported encouraging safety and efficacy with multiple cycles of ⁶⁷Cu-SAR-bisPSMA based on preliminary data from the first 3 patients in cohort 4.³ Based on these data, the Safety Review Committee (SRC) recommended that the trial proceed with dosing the final 3 patients in the cohort.

To date, all 3 remaining participants in this cohort have been allocated. At the time of the follow-up report in October, 2 patients had received their first cycle of treatment, with the third expected to receive the first dose in the following weeks.² Pending a positive safety evaluation of the final 3 patients, the dose expansion phase of the trial will commence with 14 participants.

Cohort 4 is the first cohort in the trial to assess multi-dose treatment of ⁶⁷Cu-SAR-bisPSMA at the highest dose level of 12 GBq.

Based on the first 3 patients in the cohort, no DLTs have been reported, which is in line with results from cohorts 1, 2, and 3 in the trial. Additionally, almost all adverse events were either mild or moderate, with the majority having resolved or improved at the last assessment.

Regarding efficacy, all 3 initial patients achieved a reduction in prostate-specific antigen (PSA) following 2 doses of ⁶⁷Cu-SAR-bisPSMA. To date, the largest PSA decline has been 95.7%.

Overall, the multi-center phase 1/2a SECuRE trial is evaluating the safety and efficacy of ⁶⁷Cu-SAR-bisPSMA in the treatment of patients with mCRPC. In the study, ⁶⁴Cu-SAR-bisPSMA is used to visualize PSMA-expressing lesions to select candidates for therapy with ⁶⁷Cu-SAR-bisPSMA.

In total, the phase 1/2a study has enrolled approximately 44 heavily pre-treated patients with mCRPC across the US and Australia.⁴ Patients enrolled in cohort 4 of the study received multiple treatment cycles of ⁶⁷Cu-SAR-bisPSMA (range, 2 to 4) at the dose level of 12 GBq. Previous cohorts (1-3) had received ⁶⁷Cu-SAR-bisPSMA at ascending single-dose levels.

Final completion of the study is anticipated for September 2026.

References

1. Clarity and Nucleus RadioPharma sign Master Services Agreement and Cu-67 SAR-bisPSMA Clinical Supply Agreement. News release. Clarity Pharmaceuticals. November 11, 2024. Accessed November 12, 2024. https://www.claritypharmaceuticals.com/news/nucleus/

2. Copper-67 SAR-bisPSMA updates. News release. Clarity Pharmaceuticals. October 16, 2024. Accessed November 12, 2024. https://www.claritypharmaceuticals.com/news/copper-67_sar-bispsma_updates/

3. SECuRE trial advances: No dose limiting toxicities and strong preliminary efficacy data in first multi-dose cohort. News release. Clarity Pharmaceuticals. September 12, 2024. Accessed November 12, 2024. https://www.claritypharmaceuticals.com/news/c4_update/

4. 64Cu-SAR-bisPSMA and 67Cu-SAR-bisPSMA for identification and treatment of PSMA-expressing metastatic castrate resistant prostate cancer (SECuRE) (SECuRE). ClinicalTrials.gov. March 27, 2024. Accessed November 12, 2024. https://clinicaltrials.gov/study/NCT04868604