The FDA has cleared a second drug for Duchenne muscular dystrophy, giving the green light to Marathon Pharma's corticosteroid Emflaza for patients aged five or more with the disease.
Emflaza (deflazacort) is the first corticosteroid to be approved by the FDA to treat DMD, said the US agency in a statement. The agency granted orphan and priority review status for the drug, which is the second DMD treatment to be approved in the US after Sarepta Therapeutics' exon-skipping therapy Exondys 51 (eteplirsen).
"For the first time, patients in the US with Duchenne will have widespread access to an FDA approved medicine that is indicated for all genetic forms of the condition," said Marathon's chief executive Timothy Cunniff, alluding to the fact that Exondys 51 is only approved to treat DMD caused by a specific mutation that appears in around 13% of patients.
However, it remains to be seen whether the drug will displace off-label and cheaper generic corticosteroids such as prednisone, which are already widely used to manage symptoms in DMD, a rare genetic disorder that causes progressive muscle deterioration and weakness.
Complicating the picture is that deflazacort has been available outside the US for decades and patients have been able to import it for personal use. Paradoxically, now that it is an approved medicine that is no longer a legal option, reports Reuters.
Marathon insists that Emflaza causes fewer side effects than prednisone and so warrants premium pricing. It has priced the new product at $89,000 per year, ahead of any discounts or rebates, while prednisone can be had for as little as $50 per month.
The company says it is "committed to working closely with payers to meet the patient and payer needs for acceptable access to Emflaza," including free access to the drug for patients without insurance.
In a year-long phase III trial, deflazacort was able to achieve a significant improvement over placebo on a lung function measure and muscle strength, with a non-significant trend towards an improvement on functional measures, such as time to stand from supine, time to climb four stairs and time to walk or run 30 feet.
Prednisone served as the active comparator in that trial, and was unable to achieve a significant improvement over placebo on lung function although it performed numerically better than placebo.
The Muscular Dystrophy Association (MDA), which was involved in the trials of Emflaza, welcomed the approval, saying the drug has shown "meaningful benefits for patients living with DMD and has the potential to delay disease progression”.
"We now have a treatment option for kids and adults with Duchenne, which is a major advance for the community," said MDA chief medical and scientific officer Valerie Cwik.
"As a physician, I participated in a clinical trial of Emflaza and have a keen awareness about what the approval of this drug means for patients and families."