Clarity Pharmaceuticals reveals encouraging early results from the SECuRE trial, with substantial PSA reductions and multiple complete responses at the 8 GBq 67Cu-SAR-bisPSMA dose level in advanced prostate cancer patients.
- 74% of patients achieved ≥25% PSA reduction at 8 GBq dose
- 31% of evaluable patients reached complete response or undetectable disease
- Treatment generally well tolerated with mostly mild to moderate adverse events
- Seven total complete responses reported across program, five at 8 GBq dose
- Phase III registrational trial planning underway as recruitment continues
Strong PSA Reductions Signal Therapeutic Potential
Clarity Pharmaceuticals (ASX:CU6) has delivered a compelling update from its SECuRE trial evaluating the 8 GBq dose of 67Cu-SAR-bisPSMA in metastatic castration-resistant prostate cancer (mCRPC). Preliminary data from 19 participants show that 74% achieved a prostate-specific antigen (PSA) decline of at least 25%, with 63% reaching a 50% reduction and over a quarter achieving a 90% drop. These PSA responses, a key biomarker in prostate cancer, highlight the agent's potential in heavily pre-treated patients.
Complete Responses Mark Significant Clinical Activity
Radiographic assessments further bolster the case for 67Cu-SAR-bisPSMA’s efficacy. Among the 16 evaluable patients, 81% experienced disease control, including 31% achieving complete response or undetectable disease by RECIST criteria or bone scans. Notably, two additional complete responses emerged in the latest data cut-off, bringing the total to seven across the program, with five from the 8 GBq dose cohorts. This represents nearly a third of evaluable patients at this dose level, a remarkable outcome in a population with extensive prior therapies.
Safety Profile Supports Further Development
The safety profile at the 8 GBq dose remains encouraging. Most adverse events were mild or moderate and transient, predominantly gastrointestinal and haematological in nature. Common side effects included dry mouth and nausea, with only one participant experiencing Grade 3 lymphocyte and white blood cell count decreases. Importantly, no Grade 4 or higher related events were reported, and adverse event rates were generally lower than in the broader trial population.
Trial Progress and Strategic Outlook
The SECuRE trial continues to recruit in its Cohort Expansion phase, with plans for a Phase III registrational trial underway. Clarity’s Executive Chairperson Dr Alan Taylor emphasised the unique combination of their SAR chelating technology and the bivalent bisPSMA structure as key to the observed clinical benefits. The company is also exploring combination therapies, including concomitant enzalutamide administration, reflecting evolving treatment paradigms.
These data come amid Clarity’s broader clinical and commercial momentum, including a robust cash position and manufacturing agreements supporting future supply. The early signs from SECuRE suggest 67Cu-SAR-bisPSMA could carve out a meaningful role in the challenging landscape of advanced prostate cancer treatment.
Bottom Line?
While preliminary, the SECuRE trial’s data reinforce 67Cu-SAR-bisPSMA’s promise as a potent and tolerable therapy warranting accelerated development.
Questions in the middle?
- Will the Phase III trial confirm durable responses observed at 8 GBq dose levels?
- How might combination regimens with agents like enzalutamide enhance efficacy or safety?
- What regulatory hurdles remain before 67Cu-SAR-bisPSMA can reach broader clinical use?