Aura Biosciences announced positive phase 2 end-of-study results evaluating belzupacap sarotalocan (bel-sar; AU-011) for the first-line treatment of early-stage choroidal melanoma (CM). The results were presented at The Retina Society’s 57th annual meeting held September 11-15 in Lisbon, Portugal.

According to the company, the phase 2 study is an open-label, ascending single- and repeat-dose escalation trial in patients with early-stage CM (small CM and indeterminate lesions). The study is designed to evaluate the safety, tolerability, and efficacy of up to three cycles of bel-sar treatment.

A total of 22 patients were enrolled in the trial, which included both single and multiple ascending dose cohorts. Patients were closely monitored during a 12-month follow-up period to assess tumor control, visual acuity preservation, and tumor growth rate.

As summarized in the Aura’s press release, the phase 2 results demonstrated that bel-sar achieved an 80% tumor control rate—8 patients among the 10 phase 3–eligible patients who received the therapeutic regimen. There was complete cessation of growth after treatment among responders (post-treatment average growth rate of 0.011 mm/yr among responders compared to 0.351 mm/yr before entry in the study; P < .0001).

Visual acuity preservation was achieved in 90% of these 10 patients and 80% of these 10 patients were at high risk for vision loss with tumors close to the fovea or optic disc, highlighting the potential for vision preservation with this class of drugs. The company noted that the current standard of care is radiotherapy, which leads to visual acuity of <20/200 (the cutoff for legal blindness) in the treated eye in up to 87% of patients.

The phase 2 results are a significant achievement considering the typically poor prognosis associated with CM, which is a rare and life-threatening ocular cancer in which there are no approved vision-preserving therapies to date, stated Aura.

The company further reported that the safety profile of bel-sar was highly favorable in all participants regardless of dose. There were no treatment-related serious adverse events. Ocular treatment-related adverse events were mild (Grade 1), included anterior chamber inflammation (18%) or cell (9%) and resolved without sequelae.

The majority (approximately 70%) of the anterior chamber inflammation/cell events were self-limited, required no treatment, and resolved in a median of 6 days. For those events that did require treatment, topical steroid eye drops administered for a median of 6 days achieved complete resolution of the inflammation. Eye pain occurred in 9% of patients and was mild (Grade 1). No treatment-related posterior inflammation events (no vitritis, choroiditis, retinitis, retinal pigment epithelium changes, or vasculitis) were reported.

“Many patients with early-stage CM currently face the difficult choice of whether to treat the cancer and risk losing their vision in the treated eye, or delay treatment and risk the tumor progressing,” commented Ivana Kim, MD. “The phase 2 end-of-study data that I presented at The Retina Society annual meeting showed 80% tumor control rate, 90% vision preservation, and a highly favorable safety profile in early-stage CM. Bel-sar has the potential to become the first treatment that achieves the dual goals of treating the tumor while also preserving vision, which could change the treatment paradigm for patients with this disease.”

Dr. Kim is Director of the Ocular Melanoma Center, Mass Eye and Ear, and Harvard Medical School in Boston, Massachusetts.

Finally, Aura advised that the company has received written agreement from the FDA under a Special Protocol Assessment for the design and planned analysis of the global phase 3 CoMpass trial indicating concurrence by the FDA with the adequacy of the study, if successful, to address the objectives necessary to support Aura’s planned biologics license application submission.