Durham firm's gene therapy helps patients see first snowflake, star

A gene therapy being developed by a small company in Durham has significantly improved the vision of some patients in a clinical trial.

Atsena Therapeutics is a biotechnology company developing gene therapies that target diseases that cause blindness. One of its programs, called called ATSN-101, was recently evaluated in a Phase1/2 clinical trial involving patients with a rare inherited retinal disease — called Leber congenital amaurosis 1, or LCA1 — that typically causes blindness in early childhood.

There were 15 patients involved in the study, nine of whom received the highest dose level of the therapy. Those patients experienced "clinically significant improvements in retinal sensitivity" with no "drug-related serious adverse events," according to study results recently published in the medical journal The Lancet.

One patient, after receiving the therapy, was able to able to read the ingredients on her child's halloween candy, while another was able to see the lines in a crosswalk to safely cross the street.

The primary outcome evaluated in the trial was the incidence of treatment-emergent adverse events, which refers to an "untoward medical occurrence that develops or worsens in severity during the study," according to The Lancet. Other secondary endpoints included different vision tests, including one that measures light sensitivity and another that was structured as a physical maze that patients had to navigate at various light levels.

As a first in-human study, the company did not know exactly what to expect, although it was hoping to see some efficacy in patients, Chief Medical Officer Kenji Fujita said. The primary objective of the trial was to evaluate the safety and tolerability of the gene therapy. But the results of the study were about as good as the company could have expected, Fujita said.

As for what this actually means for patients, Fujita said the patients who received the highest treatment dose experienced improvements in vision. One of the most dramatic examples of improvement came via a video that Atsena received from a parent filming a patient who was able to see snowflakes for the first time in her life. Meanwhile, another patient reported seeing a star for the first time.

Following these positive results, the company's next step would be to evaluate the therapy further in a large global Phase 3 trial that could support a potential regulatory approval. But conducting a trial of this size would be a huge lift for a small company like Atsena, Fujita said. Instead, the biotech is negotiating a partnership with a larger pharmaceutical company that would help fund the study. Atsena hopes to have this partnership finalized by the end of the year.

As Atsena advances this program, the biotech is also evaluating a different gene therapy for another rental disease caused by a mutated gene. Fujita said the company is nearly finished with the first part of the trial, after which, it will review the data and decide what doses to take into the next part of the study.

The company last year confirmed it had trimmed its workforce and prioritized its resources toward this program, called ATSN-201, which targets X-linked retinoschisis (XLRS), a disease with no approved treatment that causes progressive vision loss. The company about a year ago raised about $24.5 million in a Series B round, which CEO Patrick Ritschel said would enable the biotech to achieve topline results in the ongoing Phase 1/2 clinical trial for XLRS.