Sydney, Australia, October 8, 2026
Clarity Pharmaceuticals has achieved the recruitment target for the main group of the Cohort Expansion phase of its Phase I/IIa SECuRE clinical trial, marking an important milestone in the development of its investigational radiopharmaceutical ⁶⁷Cu-SAR-bisPSMA for metastatic castration-resistant prostate cancer (mCRPC). The main group includes 16 participants who are being evaluated for the safety and efficacy of up to six treatment cycles at an 8 GBq dose. Recruitment remains ongoing for an additional group investigating ⁶⁷Cu-SAR-bisPSMA in combination with enzalutamide, an androgen receptor pathway inhibitor. The study is designed to assess the potential of targeted copper-based radiopharmaceutical therapy in patients whose prostate cancer has progressed despite previous treatment. The latest recruitment milestone supports the continued clinical evaluation of Clarity’s targeted copper theranostic platform.
SECuRE Trial Advances Radiopharmaceutical Treatment
The SECuRE study evaluates a theranostic approach designed to combine diagnostic imaging with targeted cancer treatment. It uses ⁶⁴Cu-SAR-bisPSMA for imaging and ⁶⁷Cu-SAR-bisPSMA for therapy, enabling researchers to investigate prostate-specific membrane antigen (PSMA)-expressing cancer lesions and subsequently deliver targeted treatment. The Phase I/IIa trial is a multicentre, single-arm study planned to enrol approximately 54 participants in the United States. The Cohort Expansion phase aims to assess the safety and efficacy of ⁶⁷Cu-SAR-bisPSMA in 24 patients with mCRPC before taxane or radioligand-based therapies. The planned cohort includes approximately eight participants receiving the radiopharmaceutical alone and 16 participants receiving it alongside enzalutamide. This combination group is intended to explore whether adding an androgen receptor pathway inhibitor could provide further benefit. Achieving the main-group recruitment target means the planned 16 participants have been enrolled in that group; it does not mean the entire Cohort Expansion phase or the overall clinical trial has completed recruitment. The company expects further updates as data from recently enrolled participants mature.
Earlier Data Show PSA Declines and Disease Control
Clarity’s August 5, 2026 update reported preliminary findings from 19 participants evaluated at the 8 GBq dose level, including participants from both the Dose Escalation and Cohort Expansion phases. After a median of two treatment cycles, 74% of evaluable participants achieved a PSA reduction of at least 25%, while 63% achieved a reduction of at least 50%, 53% achieved at least 75%, and 26% achieved at least 90%. Among 16 participants evaluable for radiographic assessment, 81% achieved disease control in that preliminary analysis. This included participants with stable disease and those assessed as having a complete response or undetectable disease using the relevant assessment methods. Across the programme, seven participants had achieved complete response or undetectable disease by the data reported in the August update. The company also reported that most related adverse events in the assessed group were mild or moderate and transient. These findings are preliminary and should be interpreted in the context of the small participant population, ongoing follow-up and continued clinical development. They are results reported previously, rather than new efficacy findings generated by the October recruitment announcement.
Advertisement
SAR-bisPSMA Supports Clarity’s Theranostic Strategy
Clarity’s SAR-bisPSMA technology combines two PSMA-targeting agents with its proprietary SAR platform, which is designed to hold copper isotopes within a chelator structure. Copper-64 supports imaging, while copper-67 is being investigated for therapeutic use. The platform is intended to enable targeted detection and treatment within a coordinated theranostic approach. The company is continuing to recruit participants for the enzalutamide combination group and plans to provide additional updates as the clinical evidence develops. Clarity has also indicated that it is planning a potential registrational Phase III theranostic trial based on preliminary results to date. Such planning does not establish that a Phase III trial has begun or that the investigational product has demonstrated regulatory approval-level evidence. ⁶⁴Cu-SAR-bisPSMA and ⁶⁷Cu-SAR-bisPSMA remain investigational products. Their safety and efficacy have not been assessed by authorities such as the US Food and Drug Administration or Australia’s Therapeutic Goods Administration, and commercial availability is not guaranteed. The recruitment milestone nevertheless represents progress in evaluating targeted copper radiopharmaceuticals as a potential treatment approach for patients with advanced prostate cancer.
Source: Clarity Pharmaceuticals press release
