Clarity Pharmaceuticals' SECuRE Trial Shows Promising Results for Advanced Prostate Cancer Treatment
核心洞察
Clarity Pharmaceuticals (搜索)' SECuRE trial continues Phase II expansion after Safety Review Committee confirms favorable safety profile and promising efficacy of 67Cu-SAR-bisPSMA in heavily pre-treated metastatic castration-resistant prostate cancer patients.
All nine evaluable participants showed PSA declines, with 66.7% achieving greater than 50% PSA reduction and one patient achieving undetectable PSA levels with no metastatic disease on imaging after three treatment cycles.
The radiopharmaceutical demonstrated manageable toxicity with most adverse events being Grade 1 or 2, primarily nausea and lymphopenia, supporting progression toward Phase III registrational trials.
Clarity Pharmaceuticals (搜索) announced that its SECuRE trial will continue without protocol modifications following a positive Safety Review Committee (SRC) assessment of interim Phase II data for 67Cu-SAR-bisPSMA, a novel radiopharmaceutical targeting metastatic castration-resistant prostate cancer (mCRPC). The committee's decision was based on data from nine participants with evaluable results as of November 25, 2025, demonstrating both favorable safety and promising efficacy outcomes.
Strong Efficacy Signals in Heavily Pre-treated Population
The interim analysis revealed compelling efficacy results in a challenging patient population. All six participants with at least two PSA measurements following treatment showed PSA declines. Among these, four participants (66.7%) achieved PSA reductions of 50% or greater (PSA50), while two participants (33.3%) demonstrated PSA reductions exceeding 80% (PSA80).
The study population represented advanced disease with significant treatment history. The majority of participants (66.7%) presented with bone metastases at enrollment, and 55.6% had received more than five previous anti-cancer regimens. The median baseline PSA was 18.9 ng/mL, ranging from 1.5 to 30.2 ng/mL.
Most participants received at least two cycles of 8 GBq 67Cu-SAR-bisPSMA, with two participants also receiving concomitant enzalutamide as part of a combination therapy approach.
Remarkable Complete Response Case
One particularly notable case involved a 64-year-old man with bone metastases and a baseline PSA of 5.4 ng/mL. Following his first treatment cycle, this participant experienced a dramatic 95.2% PSA reduction. After completing three cycles of 67Cu-SAR-bisPSMA, he achieved undetectable PSA levels with no metastatic disease visible on follow-up bone scans and computed tomography imaging.
This participant experienced only mild Grade 1 adverse events, primarily gastrointestinal in nature, with no hematological or renal toxicity observed. He reported excellent quality of life following treatment, highlighting the potential for meaningful clinical benefit with manageable side effects.
Favorable Safety Profile Maintained
The safety analysis confirmed the favorable tolerability profile observed in earlier trial phases. Most treatment-related adverse events were Grade 1 or 2 in severity. The most common adverse events were nausea and lymphopenia, each occurring in 33.3% of participants (three out of nine).
Grade 3 or higher adverse events were limited to lymphopenia in three participants, some of whom had baseline bone metastases and extensive prior treatment histories including taxane chemotherapy and investigational agents. Notably, no renal toxicity or electrocardiogram changes were observed across the cohort.
For participants receiving combination therapy with enzalutamide, no new adverse events or worsening of existing events related to 67Cu-SAR-bisPSMA were documented.
Technology Platform and Market Opportunity
SAR-bisPSMA represents a novel approach utilizing Clarity's proprietary sarcophagine (SAR) technology, which securely contains copper isotopes within a cage-like chelator structure. This design prevents copper leakage into the body, addressing a key limitation of other commercially available chelators. The "bis" designation reflects the innovative approach of connecting two PSMA (搜索)-targeting agents to enhance binding and therapeutic effect.
The platform functions as a Targeted Copper Theranostic (TCT), employing copper-64 for imaging to identify PSMA (搜索)-expressing lesions and copper-67 for targeted therapy. This theranostic approach allows for patient selection and treatment monitoring within a single platform.
Executive Chairperson Dr. Alan Taylor emphasized the commercial potential, noting that PSMA (搜索)-targeted products represent blockbuster markets across multiple prostate cancer indications. The estimated combined market value for imaging in pre-definitive therapy, biochemical recurrence, and therapy in mCRPC approaches US$10-15 billion by 2030.
Trial Design and Regulatory Progress
The SECuRE trial (NCT04868604) is a multi-center, single-arm Phase I/IIa study involving approximately 54 participants across US sites. The trial progressed to Phase II expansion at the 8 GBq dose level based on favorable Dose Escalation Phase results, where 92% of pre-chemotherapy participants demonstrated PSA drops greater than 35%.
The current Cohort Expansion Phase will enroll 24 participants, with a subset receiving combination therapy with enzalutamide. This combination approach aligns with positive results from the ENZA-p trial and recommendations from the company's Clinical Advisory Board, including Prof Louise Emmett and Prof Oliver Sartor.
Clarity has received three Fast Track Designations from the FDA for SAR-bisPSMA products and maintains ongoing positive regulatory interactions. The company plans to complete Phase II recruitment in 2026 while advancing Phase III registrational trial planning based on accumulating data.
Disease Context and Unmet Need
Prostate cancer represents a significant global health burden as the second most common cancer diagnosed in men worldwide and the fifth leading cause of cancer death in men globally. In the United States, the American Cancer Institute projects approximately 313,780 new prostate cancer cases and 35,770 deaths in 2025.
The mCRPC setting represents a particularly challenging treatment landscape where patients have exhausted standard hormonal therapies and often face limited effective options. The SECuRE trial's focus on heavily pre-treated patients with bone metastases addresses this critical unmet medical need.
The interim results support continued development toward a potentially transformative treatment option for patients with advanced prostate cancer, with the goal of improving both survival outcomes and quality of life in this difficult-to-treat population.