Biogen has announced that a late-stage trial of its gene therapy timrepigene emparvovec did not meet its primary and key secondary endpoints in patients with the rare inherited eye disease choroideremia.

The Phase III STAR study enrolled 169 adult males with a genetically confirmed diagnosis of choroideremia. It evaluated the safety and efficacy of a single subretinal injection of the investigational gene therapy.

The primary endpoint was the proportion of patients with an improvement of at least 15 letters from baseline in best corrected visual acuity at 12 months post-treatment, as measured by the Early Treatment Diabetic Retinopathy Study (ETDRS) chart.

However, the study did not meet its primary endpoint, with the gene therapy failing to increase the number of patients demonstrating an improvement on this measure.

In addition, the study also did not demonstrate efficacy on key secondary endpoints, although the safety results were consistent with previous studies evaluating timrepigene emparvovec.

“We extend our deepest gratitude to all those who contributed to the STAR study, including the participants, investigators, site staff and the broader choroideremia community,” said Katherine Dawson, head of the therapeutics development Unit at Biogen.

“While we are disappointed by the results of the STAR study, we are hopeful that the clinical insights gleaned from this study may help to shape therapeutic innovation for inherited retinal diseases including choroideremia, so that in the future there may be treatment options for the community affected by these debilitating disorders,” she added.

Choroideremia is a rare genetic eye disease that causes progressive vision loss and ultimately leads to blindness.