CHMP backs Spark’s Luxturna, but rejects Sarepta again

Spark Therapeutics looks set for approval of its eye disorder gene therapy Luxturna on both sides of the Atlantic after getting a green light from the CHMP.

The EMA’s advisory committee recommended approval of Luxturna (voretigene neparvovec), for the treatment of adults and children suffering from inherited retinal dystrophy (IRD) caused by RPE65 gene mutations, a rare genetic disorder which causes vision loss and usually leads to blindness.

The decision was based on a 41-patient study which showed patients treated with the gene therapy demonstrated a significant improvement of night vision, a typical symptom of the disease, after one year, while no improvement was seen in a control group.

The CHMP has backed the therapy on the understanding that Spark will carry out follow-up studies to keep tabs on Luxturna’s safety and efficacy over the next 15 years. Once approved, Luxturna will be sold in Europe by Novartis, which has been steadily building a portfolio of cell and gene therapies in the last couple of years through licensing deals.

Luxturna was approved in the US towards the end of last year, becoming the first directly-administered gene therapy to be cleared for marketing by the FDA, although Spark immediately courted controversy by setting the price of the treatment at $425,000 per eye. That was at the top-end of analyst expectations, although Spark has offered a rebate scheme tied to clinical outcomes.

Sales of the therapy were less than $7m in the first six months of this year – equivalent to six vials of the drug in the first quarter and 12 in the second – and according to Spark the “early … launch indicators have been very positive.” The European price will as ever depend on negotiations with member state reimbursement authorities.

This type of IRD affects somewhere between 1,000 and 2,000 people in the US with around 10 new cases per year, and a similar number in the EU.

Sarepta setback

There was bitter news from the CHMP for Sarepta, as the panel turned down its application for Duchenne muscular dystrophy drug Exondys (eteplirsen) for a second time, setting up a formal rejection by the EMA later this year.

Eteplirsen was approved in the US as Exondys 51 in 2016, although the decision came after FDA reviewers recommended that the drug be rejected as the evidence for its benefits was slim. They were ultimately overruled by the FDA’s leadership including former Commissioner Robert Califf, despite concerns that the decision would set the bar for approval too low for rare disease therapies.

The CHMP turned down Sarepta’s application for Exondys in May, but was asked to re-examine the evidence by the company. It confirmed the refusal at the latest meeting, saying it was concerned that “the main study, which involved just 12 patients, did not compare Exondys with placebo beyond 24 weeks, during which there was no meaningful difference between Exondys and placebo in the 6-minute walking distance.”

The controversy over the efficacy of Exondys hasn’t held up sales progress in the US, however, with Sarepta reporting revenues from the drug of $138m in the first six months of this year – around double the level in first-half 2017 – setting it on track to meet sales targets of around $300m in 2018 as a whole.