Aura Biosciences Announces Positive Phase 2 Results for Bel-sar in Early-Stage Choroidal Melanoma

Aura Biosciences, a biotechnology firm focused on developing treatments for solid tumors, reported promising results from its Phase 2 clinical trial of bel-sar (AU-011) for treating early-stage choroidal melanoma (CM), a potentially vision-impairing and life-threatening eye cancer. The results were disclosed at The Retina Society Annual Meeting in Lisbon, Portugal.

The Phase 2 study evaluated bel-sar in patients with early-stage CM, including small choroidal melanomas and indeterminate lesions. The open-label trial involved single and multiple dose escalation, with 22 patients monitored over 12 months to assess tumor control, visual acuity preservation, and tumor growth rate.

Results showed that bel-sar achieved an 80% tumor control rate in Phase 3-eligible patients, with responders experiencing a complete halt in tumor growth. The average post-treatment growth rate fell to 0.011 mm/year, compared to 0.351 mm/year before the study. Visual acuity was preserved in 90% of these patients, most of whom had tumors close to the fovea or optic disc, posing a high risk for vision loss.

Remarkably, 80% of those treated were at significant risk for vision impairment, underscoring bel-sar’s potential as a vision-sparing therapy. Current standard treatments, like radiotherapy, often result in severe vision loss, with up to 87% of patients experiencing visual acuity below 20/200 in the treated eye.

Bel-sar also demonstrated a highly favorable safety profile. No serious adverse events linked to the treatment were reported. Mild ocular treatment-related adverse events included anterior chamber inflammation (18%) or cell presence (9%), which resolved without long-term effects. Most inflammation events were self-resolving within six days, and for those requiring treatment, topical steroid eye drops effectively managed the condition. Additionally, no treatment-related posterior inflammation events, such as vitritis or choroiditis, were observed.

Dr. Ivana Kim from Mass Eye and Ear and Harvard Medical School highlighted the importance of these findings, noting that patients with early-stage CM often face the dilemma of treating the cancer at the expense of vision or delaying therapy and risking tumor progression. According to Dr. Kim, the Phase 2 results indicate that bel-sar could potentially become the first treatment to control tumors and preserve vision simultaneously, potentially transforming the treatment landscape for CM patients.

Dr. Jill Hopkins, Aura Biosciences' Chief Medical Officer, expressed confidence in bel-sar as a potential first-in-class treatment for early-stage CM. The company is currently enrolling patients in the global Phase 3 CoMpass trial, which has received a Special Protocol Assessment (SPA) from the U.S. Food and Drug Administration (FDA). This SPA indicates FDA agreement on the trial design and analysis plan, suggesting that successful trial results could support a biologics license application.

Aura Biosciences is dedicated to improving treatment options and outcomes for patients with CM and other cancers. The company continues to push forward with its development programs, including ongoing studies in other ocular oncology indications and bladder cancer.