FDA experts offer a unanimous endorsement for pioneering gene therapy for blindness

A pioneering AAV gene therapy from Spark Therapeutics took a giant stride toward an FDA approval yesterday as an outside panel of experts offered their support for getting this game-changing treatment into the market after looking over the data and hearing from some of the severely sight-impaired patients whose lives had been transformed by this therapy.

The vote was 16 to 0 favoring the benefit-risk profile of the drug, backing an OK for voretigene neparvovec by the agency’s Cellular, Tissue and Gene Therapies Advisory Committee and providing a compelling reason for the U.S. Food and Drug Administration to follow through with an historic first U.S. approval of a vector-delivered gene therapy.

“Gene therapy has made my world so much more brighter,” said one young patient, who went on to describe how he could see the moon for the first time, go out at night, watch facial expressions, and basically live his life more normally instead of waiting for blindness to take over. And Christian Guardino talked about how the treatment four years ago saved his sight, a span of time when the darkness might well have closed in.

This was no panacea. As the agency’s internal review made clear, voretigene neparvovec (or Luxturna) — which uses an adeno-associated viral vector — improved sight using the light levels measured for the primary endpoint, but fell far short of curing retinal dystrophy triggered by genetic RPE65 mutations. Improvement in vision is also limited by the number of viable retinal cells they have left at the time they’re treated, according to investigators.

The panel experts faced questions about the durability of this eye therapy, the possibility that patients will need multiple treatments in order to preserve vision gains, the right age to use it and the use of a completely novel endpoint for the primary goal when standard visual acuity achievements fell far short of the goal on statistical significance.

The experts, though, seemed generally impressed by the results—with some reservations about the endpoint—and several were open to treating very young patients. Spark is suggesting 3 and older, and CEO Jeff Marrazzo told me he was interested in the encouragement he heard to go even younger in some cases.

While a formal approval is not guaranteed, it would be confounding for the agency to ignore the panel and the roster of patients who came forward to talk about being able to play, study and participate in the kind of day-to-day activities that had been denied them all their lives. An approval here could well be the first of many to come, as a group of players advance treatments that use a benign virus to introduce a corrected gene to fix a wide range of conditions.

“It really came together in triangulating a bunch of points,” Marrazzo told me after the landmark vote came through, citing not just the patient testimony but also the physicians who were there to back up the application.

Marrazzo isn’t offering any price yet, and won’t until the approval comes through. But it won’t be cheap. Estimates for one-time costs often hover around the $1 million mark in gene therapy. The CEO, who’s obviously thought quite a lot about it, says the clear path to ensuring access under the current rules that govern insurance points to a one-time charge per eye. It’s hard to offer an alternative model, he adds, given the kind of portability issues and payment models people have with their insurance coverage today—but he’s interested in exploring it and seeing what has to change to make that happen.

Eighteen years ago, the gene therapy field was nearly shoved into oblivion after the death of a patient in a trial being conducted by Penn’s James Wilson. But over the past 10 years investigators, using some of the same technology that Wilson helped create, have mounted a massive comeback effort. In Spark’s case, the Children’s Hospital of Philadelphia played a key role in pushing the early R&D work, giving the biotech a big leg up in the race to get the first such gene therapy into the U.S. market.

There have been two other gene therapies in Europe, including GlaxoSmithKline’s Strimvelis. But they’ve been rarely used. The question now is how these treatments can get rooted in the U.S. market and then start to spread around the world.

That day looks much closer than it has ever been.

Katherine High, president and head of R&D at Spark Therapeutics said: “The clinical program for Luxturna includes patient data that show efficacy for up to four years on endpoints including bilateral multi-luminance mobility test (MLMT) score change and full-field light sensitivity threshold (FST) testing, with observation ongoing. We look forward to continuing to work with FDA as it completes its review of Luxturna.”

Reprinted from Endpoints News. Copyright 2017. Endpoints News reports and analyzes the top global biotech and pharmaceutical R&D news of the day. Sign up for its free reports at https://endpts.com