Aura Biosciences, Inc. announced the presentation of positive interim Phase 2 safety and efficacy data of bel-sar with 9-10 months of follow up evaluating two key clinical endpoints: tumor control and visual acuity preservation using the suprachoroidal (SC) route of administration for the first-line treatment of patients with early-stage choroidal melanoma (indeterminate lesions and small choroidal melanoma (IL/CM)). The results were presented at the Macula Society 46th Annual Meeting held February 15-18, 2023, in Miami, FL. This Phase 2 trial (NCT04417530) is assessing the safety and preliminary efficacy of single- and multiple ascending-doses of bel-sar up to three cycles of treatment via SC administration for the first-line treatment of early-stage choroidal melanoma.

A total of 20 adult patients have been enrolled in the trial including the single dose Cohorts 1-3 (n=6) and multiple dose escalation Cohorts 4-6 (n=14). Cohorts 5 and 6 received up to three cycles of therapy, which was considered the therapeutic regimen for evaluation. One patient in Cohort 5 (n=3) received two cycles of therapy and two patients in Cohort 5 received three cycles of therapy (40 µg/dose).

All patients from Cohort 6 (n=8) were assigned to receive three cycles of therapy at the highest dose (80 µg/dose). One patient from Cohort 6, who discontinued after one cycle due to unrelated serious adverse events (SAEs), is not included. All patients in Cohorts 5 and 6 had active growth at study entry, as an enrichment strategy to evaluate preliminary efficacy.

This group of patients with active growth treated at the therapeutic regimen of three cycles was evaluated for tumor growth rate, tumor control, and visual acuity preservation as the defined clinical endpoints to evaluate preliminary efficacy. The results, with an average of nine months of follow up in patients who received three cycles of therapy in Cohorts 5 and 6, and who match the criteria for the planned global Phase 3 trial, showed a statistically significant reduction in the tumor growth rate (-0.289 mm/yr, p = <0.0001) compared to each patient's documented growth rate at study entry, and a 100% (8/8) tumor control rate. In addition, the visual acuity preservation rate was 88% (7/8) in these cohorts, with the majority of patients being at high-risk for vision loss with tumors close to fovea or optic disk.

The overall tolerability profile of bel-sar was generally favorable, with no dose-limiting toxicities, treatment-related SAEs or significant AEs reported as of January 10, 2023. There was no posterior inflammation and only mild anterior inflammation (Grade 1) in 20% of the patients. Treatment-related AEs were predominantly mild and resolved without sequalae.