S going to Therapeutics realized a startling concern Monday when the Food and Drug Administration rejected its marketing application for a second drug aimed at treating children with Duchenne muscular dystrophy, a rare, inherited muscle-wasting waste.  In a statement, Sarepta stated that the FDA had rejected its drug approval, called Vyondys 53, because of the risk of infections related to intravenous port infusion and renal toxicity seen in experiments in animals.
Sarepta shares fell 13% to $ 105 in after-hours trading. The stock ended the regular trading session down 4%.
The FDA did not release its own statement explaining the negative decision, but the denial of Vyondys 53 is an unusual example in which the agency is stepping back against a company that is seeking fast approval for a rare-disease drug based on an early biomarker ̵1; and before substantial evidence of patient benefit was obtained. to facilitate the development of medicines for non-medical devices. The decision to reject Vyondys 53, therefore, could represent a new and more restrictive regulatory policy at the FDA, which could affect all companies that develop medicines for rare diseases.
But it could also be related to Sarepta, who had been in a relationship with the agency for many years.
"We are really surprised to receive the complete response letter this afternoon," Sarepta CEO Doug Ingram said in a statement. "Throughout the course of its review, the agency did not raise any issues suggesting golodirsen disapproval, including issues that formed the basis of a complete response letter." Golodirsen is the scientific name for Vyondys 53.
The company has submitted data to the FDA showing that Vyondys 53, which is administered through a weekly infusion, has made a small increase in an important protein of muscle called dystrophin that is commonly lost in children with Duchenne. 53 has the potential to improve muscle function of Duchenne patients or slow the development of disease. Sarepta is betting on a fast FDA approval, before having to confirm the treatment benefit in a final clinical trial.
Sarepta used the same strategy in 2016 to obtain an expedited approval for his first Duchenne drug, called Exondys 51. The verdict was controversial. Advisers outside the FDA – and even some of the agency's staff members – conclude there is not enough evidence to show that Exondys 51 was effective in treating Duchenne.
Top FDA officials, led by Dr. Janet Woodcock, ignored the negative recommendations and still approved the drug, in part because of intense pressure from families of children with Duchenne.
With approval in 2016, Sarepta was able to grow Exondys 51 into a product that generates $ 300 to $ 400 million in sales annually. However, the company has fallen years behind schedule completing clinical trials required by the FDA to confirm the true benefit of the drug, as reported by STAT last week.
Sarepta's susceptibility to Exondys 51 may have angered the FDA enough to play a role in The agency's decision Monday to reject Vyondys 53.
Sarepta said it plans to meet with the FDA to meet the requirements. issue that caused the FDA to reject the drug. A study confirming Vyondys 53 is currently underway, but data on improving muscle function are not expected for three or four years. 53. Approximately 8% of 5,000 Duchenne patients in the US carry 53 errors. Exondys 51 is used to treat 13% of sick patients caused by a DNA sequence error known as exon 51.