Gene Therapy for Inherited Retinal Disease Achieves a Historic Milestone
This has been an amazing year in the world of drug development, with three new therapeutic classes marking historic gains. We first saw Novartis’ FDA approval for the first CAR-T immunotherapy. Then Alnylam’s RNAi treatment achieved Phase 3 success, the first such for that class of therapeutics. Most recently, Spark Therapeutics received a unanimous recommendation on October 12 from the FDA Advisory Committee for their gene therapy Luxturna (voretigene neparvovec), which is widely expected to result in an FDA approval for the therapeutic by January 12.
The Spark treatment uses an Adeno-Associated Virus (AAV) vector to deliver a functional copy of the RPE65 gene that is implicated in an inherited retinal disease that causes those affected to have poor vision at birth and progress to blindness. Approximately 3,500 people in the United States and five major European countries have the disease, for which no treatment has existed.
Spark’s gene therapy is injected into the eye. In the pivotal trial reviewed by the Advisory Committee, 31 patients aged 4 to 44 years were randomized to the gene therapy or no treatment. Ninety-three percent of the treated patients showed improvement in their vision within 30 days, as measured by their ability to navigate obstacles in low light. The gene therapy was not a cure, but the patients who testified before the Advisory Committee said that even if their vision was not completely restored, the vision they regained greatly improved their lives. Moreover, the treatment appears to be long-lasting; Spark presented data extending as long as four years from treatment, showing that the improvement persisted.
If approved by FDA as expected by the agency’s decision data of January 12, Luxturna will be the first gene therapy to gain approval in the United States. Two other gene therapies have been approved in Europe, but UniQure’s Glybera has since been withdrawn from the market and Glaxo Smith-Kline’s Simvetis is rarely used. Analysts speculate the Spark approval could mean good news for other companies developing gene therapies, a group that includes Audentes, BioMarin, Rengexbio, UniQure, and Ultragenex. While those, like Audentes, who are working on gene therapeutics for other conditions with no treatment alternatives, are likely to have similarly positive receptions assuming their clinical data is good, companies developing therapies for conditions like hemophilia — where therapeutic alternatives currently exist — may face more scrutiny.
As usual, the discussion about pricing such a novel, life-changing, and long-lasting treatment as Luxturna now comes to the forefront. Spark Therapeutics has not yet revealed what they might seek in payment, but speculation has ranged as high as $1 million — a not insignificant sum.