The Food and Drug Administration has approved the latest entrant into the market for drugs to treat spinal muscular atrophy.
South Plainfield, New Jersey-based PTC Therapeutics said Friday that the FDA had approved Evrysdi (risdiplam) as the first orally administered drug for SMA for use at home by children and adults aged 2 months and older. The company also plans to file for approval with the European Medicines Agency. Genentech, part of Swiss drugmaker Roche, will market Evrysdi in the U.S.
Shares of PTC were up less than 2% on the Nasdaq on Monday afternoon.
“We started looking for treatments for SMA more than a decade ago,” SMA Foundation President Loren Eng said in a statement. “PTC was one of the companies that embraced and remained committed to the idea of developing a truly innovative therapeutic for this disease.”
The approval is based on results of two Phase II/III trials, SUNFISH and FIREFISH, both of which were sponsored by Roche. In FIREFISH, which enrolled 62 patients, 41% of 17 infants treated with the drug were able to sit without support for at least five seconds, while 90% of 21 were alive without permanent ventilation and reached at least 15 months of age. Eighty-one percent of 21 were alive without permanent ventilation after at least 23 months of treatment and reached an age of 28 months or older, with median of 32 months.
SUNFISH, a placebo-controlled study of 231 patients, showed a statistically significant change in the primary endpoint of change in baseline Motor Function Measure-32 score of 1.55 points at 12 months.
A Deep-dive Into Specialty Pharma
A specialty drug is a class of prescription medications used to treat complex, chronic or rare medical conditions. Although this classification was originally intended to define the treatment of rare, also termed “orphan” diseases, affecting fewer than 200,000 people in the US, more recently, specialty drugs have emerged as the cornerstone of treatment for chronic and complex diseases such as cancer, autoimmune conditions, diabetes, hepatitis C, and HIV/AIDS.
Two other drugs approved for treating SMA are Biogen’s Spinraza (nusinersen) and Novartis’ gene therapy Zolgensma (onasemnogene abeparvovec-xioi).
In a note to investors following the approval, Cowen analyst Joseph Thome wrote that Zolgensma will likely be the leading player in SMA patients younger than 2 years, especially those diagnosed at birth due to screening, while Evrysdi will play a greater role in those older than 2 or who prefer the convenience of oral therapy. He further noted that the company had indicated an annual price of less than $100,000 for an infant younger than 2 years weighing less than 15 pounds – the average weight of infants in the FIREFISH study. Cowen’s model had estimated an annual wholesale acquisition cost of $325,000.
RBC Capital Markets analyst Brian Abrahams called it “somewhat surprising” that Evrysdi would be priced at a discount compared to Spinraza and Zolgensma, which he wrote could help increase market share and rapidity of adoption, but would produce lower per-patient revenue than anticipated.
Photo: Waldemarus, Getty Images
