Another step backwards for Editas

Progress-hungry investors who have struggled with the pace of development in the gene editing field will find little of comfort in Editas’s announcement today. Work on the group's lead project, EDIT-101 for Leber congenital amaurosis 10, is being paused while a partner is sought, a decision the company says was based on commercial viability rather than efficacy. Of the first 14 patients enrolled into the Brilliance trial only three responded, two of whom were homozygous for a mutation implicated in the rare disease, which causes blindness. Editas contends that this means that homozygosity could be used as a predictor of response and guide enrolment into any pivotal study; however, this restricts the addressable US population to a mere 300 people. Given that an earlier Brilliance readout disappointed this feels like a prudent decision, but finding a partner is going to be tough. The broader implications here are also concerning. On a call executives admitted that preclinical data did not predict that only certain genotypes would respond, while ramifications for other inherited retinal disease assets are “unclear”, Stifel analysts noted. Editas has one other project in the clinic, but this is clearly a setback. Its shares opened down 18%.