LHON gene therapy shows sustained efficacy, safety

GenSight Biologics announced promising long-term findings from a phase 1/2 trial of GS010, an intravitreal gene therapy for Leber’s hereditary optic neuropathy (LHON).

The early-stage trial involved 14 patients with an ND4 mutation who received a single dose of GS010 in their worse-seeing eye. At 96 weeks, eyes that were treated with the AAV-mediated treatment gained a mean of 21 ETDRS letters from baseline (P=0.02)

According to the press release, the treatment was most effective in the 5 patients whose vision loss had begun less than 2 years prior to enrollment. These eyes displayed a mean gain of 29 ETDRS letters compared with baseline, and approximately 60% showed clinically significant gains of 15 or more ETDRS letters.  

There were no reported cases of worsening vision, ocular sequelae, serious adverse events or systemic adverse events. Most ocular-adverse events were mild and reversible.

"The confirmatory safety and continued positive trends after 2 years of follow-up confirm significant hope for patients suffering from LHON. It is worth noting that the observed improvement in some of the untreated eyes was consistent with several prior studies in neuroretinal degenerative diseases,” said Catherine Vignal, MD, chief of the department of ophthalmology at the Rothschild Foundation Hospital in Paris and study investigator. “The insights gained from this and forthcoming data will be tremendously helpful as GenSight works to develop a therapy for this very severe disease with no existing curative treatment.”

Long-term follow-up for this trial is ongoing.

GenSight Biologics is also currently conducting two phase 3 clinical studies (RESCUE and REVERSE) in Europe and the United States to assess the efficacy of GS010. Topline results at 48 weeks for both studies are expected in the second and third quarters of 2018.