Aura Biosciences Secures FDA SPA for Phase 3 Bel-sar Trial, Expects Mid-Year Bladder Data
Aura Biosciences obtained FDA SPA for its Phase 3 bel-sar trial in early-stage choroidal melanoma, using a three-arm design and time-to-progression endpoint with top-line data expected in Q4 2027. Phase 2 showed 80% cessation with full dosing versus 80% progression on subtherapeutic regimens, and mid-year bladder cancer update is expected.
1. Phase 3 Trial Design and SPA
Aura obtained an SPA from FDA for the Phase 3 bel-sar trial in early-stage choroidal melanoma, establishing time-to-progression as the primary endpoint. The trial uses a three-arm design (high-dose, low-dose, sham) to maintain masking and is conservatively powered, with enrollment expected to complete in 2026 and top-line data due Q4 2027.
2. Phase 2 Results
In Phase 2, patients receiving the full three-cycle bel-sar regimen achieved 80% tumor growth cessation, while 80% of subtherapeutic dosing patients progressed, yielding a 60% response delta. Adverse events were limited to grade 1, underscoring the therapy’s favorable safety profile in ocular oncology.
3. Bladder Cancer Program
Aura expects mid-year data from its neoadjuvant bladder cancer study, evaluating 200µg and 400µg per lesion priming-boosting cohorts. Early immune profiling showed a 40× increase in NK cells and a 7× increase in cytolytic CD4 T-cells, with no grade 2 or higher adverse events reported.