The U.S. Food and Drug Administration (FDA) recently approved PTC Therapeutics’ supplemental New Drug Application (sNDA) for the therapy, generically called deflazacort, to include patients between ages 2 and 5. The drug was first approved by the FDA in 2017 to treat all age-eligible patients regardless of disease-causing genetic mutation.
A supplement is an application to allow a company to make changes in an already-approved product.
”We are excited to bring Emflaza to younger boys living with Duchenne muscular dystrophy,” Stuart Peltz, PhD, chief executive officer of PTC Therapeutics, said in a news release. “The standard of care is to start Emflaza at the time of diagnosis. We believe that treating patients as young as possible, when they still have a substantial amount of muscle, will have the greatest benefit for patients that are [age 2] and older.”
Originally developed by Marathon Pharmaceuticals and later acquired by PTC Therapeutics, Emflaza is a corticosteroid precursor — a substance from which an active corticosteroid, 21-desDFZ, is formed. It acts through the glucocorticoid receptor to exert anti-inflammatory and immunosuppressive effects.
U.S. approval of Emflaza was based on a series of clinical trials, including a phase 3, randomized double-blind and placebo-controlled clinical trial. The 52-week study, which included 196 boys ages 5 to 15, found that muscle strength was markedly greater at week 12 in boys taking the medication than those who took placebo. Throughout the trial, muscle strength continued to increase.
Compared to placebo, multiple assessments of participants’ function — time to walk or run 30 feet, for example — also favored the therapy.
However, the Institute for Clinical and Economic Review (ICER), an independent nonprofit organization best known as the United States’ watchdog on drug pricing, recently issued a draft report raising concerns about the cost-effectiveness of DMD drugs, including Emflaza. Along with current prices, concerns are based on limited evidence supporting Emflaza’s efficacy and safety compared to prednisone, another commonly used corticosteroid.
According to the Wall Street Journal, PTC Therapeutics last January increased the list price of the therapy to more than $65,000 annually for the therapy that, prior to U.S. approval, had been imported from Europe by some patients.
Through a support program called PTC Cares, the company is offering financial assistance programs for its products, in addition to helping people understand the prescription process.
The most common of the more than 30 types of muscular dystrophy, the progressive disorder usually affects boys, although girls can also carry the mutated gene and experience some symptoms. The mutated DMD gene gives instructions necessary to produce the dystrophin protein. Dystrophin provides structural support and muscle fiber protection. Symptoms typically begin to appear between ages 1 and 6.