Clarity Pharmaceuticals (ASX: CU6) has announced a significant advancement in its SECuRE trial, a Phase I/IIa theranostic study evaluating Cu-SAR-bisPSMA for treating metastatic castration-resistant prostate cancer (mCRPC). The Safety Review Committee (SRC) has confirmed the end of the Dose Escalation Phase and the commencement of the Cohort Expansion Phase (Phase II), based on promising efficacy and safety data observed across all cohorts. A key highlight is that 92% of pre-chemotherapy participants experienced a greater than 35% drop in prostate-specific antigen (PSA) levels. Specifically, in this group, reductions of 80% or more were achieved in almost half of the patients, predominantly with single doses of Cu-SAR-bisPSMA. Furthermore, disease control, based on radiographic assessment, was achieved in 92% of pre-chemotherapy participants who had evaluable disease at baseline.
The trial’s protocol has been amended to include participants at earlier stages of the disease, specifically those who have not received chemotherapy in the metastatic setting. The Cohort Expansion Phase will increase from 14 to 24 participants, with a subset receiving a combination of Cu-SAR-bisPSMA and enzalutamide, an ARPI (androgen receptor pathway inhibitor). The SRC recommended proceeding to Phase II at the 8 GBq dose level, increasing the number of cycles from up to 4 to up to 6. Across all cohorts, 68% of participants showed reductions in PSA levels, despite the majority (77%) receiving only a single dose. The safety profile of Cu-SAR-bisPSMA remains favorable, with most adverse events being Grade 1-2. One Dose Limiting Toxicity (DLT) occurred at the highest dose but improved after two weeks.
The company has also received three Fast Track Designations from the US FDA for SAR-bisPSMA, underscoring the potential of this novel approach. Clarity Pharmaceuticals is focused on bringing Cu-SAR-bisPSMA to earlier lines of prostate cancer therapy. The company aims to improve treatment outcomes for men with prostate cancer worldwide, addressing the high unmet need in this segment, from diagnosis to the treatment of metastatic disease.
