Infrared-activated drug halts tumor and saves vision in eye cancer patients

Aura Biosciences has reported promising results from its experimental treatment for a rare eye cancer, small choroidal melanoma. Eight out of ten patients who received a therapeutic dose of the virus-like drug conjugate, belzupacap sarotalocan (bel-sar), experienced halted tumor growth at the one-year mark. Notably, vision was preserved in nine out of these ten patients, an important factor given that existing treatments such as surgery and radiation often result in blindness or significant vision loss. This data was shared at the Retina Society’s annual meeting in Lisbon.

Elisabet de los Pinos, CEO of Aura Biosciences, emphasized that preserving visual acuity is not merely a safety measure but a critical aspect of the drug’s efficacy. She noted that if blindness were inevitable, patients could simply undergo radiotherapy, which is already available. The main objective with this type of cancer, often diagnosed early, is to prevent further tumor growth.

The Phase 2 clinical trial included 22 patients who received varying doses of bel-sar. Adverse events were mostly mild, with the most common being grade 1 inflammation in the eye reported in four cases. Encouraged by these results, Aura Biosciences launched a Phase 3 study named CoMpass in December, aiming to enroll around 100 patients.

A significant outcome from the study was the dramatic reduction in the average tumor growth rate post-treatment. For those who responded to the treatment, the growth rate dropped to 0.011 mm per year, compared to 0.351 mm per year before the study. This difference was statistically significant, with a p-value of less than 0.0001.

Bel-sar is designed to be delivered to the suprachoroidal space in the eye, where it selectively binds to tumor cells using specific sugar branches found on solid tumor cells but not on normal cells. After binding, an infrared light activates a photosensitizing drug, causing the tumor cells to rupture and die. This cell rupturing also triggers an immune response aimed at further eliminating tumor cells.

Aura Biosciences, based in Boston, originated from research conducted at the National Institutes of Health (NIH), and the company continues to collaborate with the NIH for ongoing research and animal studies. According to de los Pinos, Aura is financially supported until at least the second half of 2026.

In addition to the progress in treating eye cancer, Aura Biosciences plans to unveil data on a separate drug for bladder cancer in October.