Debra Miller, CEO and founder of CureDuchenne, a nonprofict dedicated to researching cures for Duchenne muscular dystrophy, recently released a statement following the U.S. Food and Drug Administration’s (FDA) decision to send a Complete Response Letter to BioMarin for its exon-skipping drug drisapersen (Kyndrisa).
Duchenne muscular dystrophy, a devastating disease that affects boys, has no cure, and Duchenne patients are faced with progressively weaker muscles along with pulmonary and cardiac failure. Studies have found the underlying cause of DMD is a mutation or error in the gene for dystrophin, an essential protein involved in muscle fiber function that is caused by a variant in one exon — a gene part that will become part of the mature RNA produced by that gene.
Studies for DMD are designed to skip an exon in the dystrophin pre-m RNA to enable the synthesis of a functional shorter form of the dystrophin protein, so exon-skipping is a potential treatment approach to correct for specific genetic mutations and restore production of the dystrophin protein.
“We are disappointed that the FDA did not approve drisapersen, given the significant benefit that many Duchenne boys experienced when they were on an early and consistent treatment protocol of the drug. Duchenne is a progressive and relentless muscle-wasting disease, and we cannot lose time finding therapies. Our fight to cure Duchenne muscular dystrophy goes on. This disease, with its complex genetic roots, is unlikely to be cured by any single drug. Drisapersen was expected to be beneficial to about 13 percent of all patients,” Miller said in a news release.
“We appreciate BioMarin’s professionalism and dedication in developing this drug. And we are extremely grateful to the patients and families who participated in this demanding study over the last several years. We remain hopeful that drisapersen, after further research, can still become a useful tool against Duchenne in Europe and potentially the U.S. BioMarin has other drugs in development for Duchenne which treat different mutations, and we are anxious to see the plans for those drugs go forward,” Miller said.
Eteplirsen, the lead clinical candidate under development by Sarepta Therapeutics, is designed to skip exon 51 in DMD patients. CureDuchenne’s early subsidy aided Sarepta to move the drug into human clinical trials. The organization will be supporting Sarepta at its upcoming FDA Advisory Committee meeting. PTC Therapeutics, another company funded by CureDuchenne, has recently submitted a new drug application (NDA) for FDA approval, and CureDuchenne looks forward to assisting PTC as it advances over the approval course.
BioMarin is examining the Complete Response Letter, and it will work in collaboration with the FDA to define the next stages for the application of drisapersen.
Ongoing extension trials of drisapersen will continue, as will ongoing trials for BMN 044, BMN 045 and BMN 053, three other exon-skipping drugs. Patients currently under treatment with drisapersen, BMN 044, BMN 045, and BMN 053 will stay on therapy.
“To the Duchenne community, we pledge that we are in this for the long haul. We cannot rest until there are treatments – and, ultimately, cures – for all patients with Duchenne muscular dystrophy,” Miller said.
The organization has used its effective venture philanthropy model to make investments and grants to support research in DMD. Last year, CureDuchenne made an investment of $1 million in MyoTherix Inc., a biotech that develops novel therapeutics for DMD and other muscular dystrophies. The organization has also invested $1.5 million in another biotech, Capricor Therapeutics, to advance research for heart muscle failure associated with DMD.
So far this year, CureDuchenne has funded two research projects, an anti-fibrotic and anti-inflammatory with RASRx, and a gene therapy with Bamboo Therapeutics.