First oral drug for spinal muscular atrophy approved by FDA.
The Food and Drug Administration on Friday approved the Roche and PTC Therapeutics drug Evrysdi, the first oral medicine for the rare genetic disease spinal muscular atrophy.
Evrysdi, previously known as risdiplam, is cleared to treat all SMA patients aged two months or older, regardless of the severity or type of the devastating neuromuscular condition. Roche priced the drug by patient weight, with a maximum cost of $340,000 per year — substantially less than competing, approved therapies from Biogen and Novartis.
The approval caps a remarkable change in the standard of care for a disease that, just four years ago, had no available treatments. For patients and their families, the arrival of Evrysdi presents a unique choice between a one-time gene therapy, an RNA-based drug infused three times a year at the doctor's office and a daily medicine taken at home.
Four years ago, no medicines were available for spinal muscular atrophy, a disease that causes progressive muscle weakness and is typically fatal in its most severe form, which afflicts infants.
Treatment has since changed dramatically, thanks to the arrival in short succession of three cutting-edge medicines. First came Biogen's Spinraza, approved in December 2016. A gene-targeting medicine infused into the spine, Spinraza was the first therapy proven to alter the course of SMA, helping, for instance, infants lift their heads, sit up or walk when they may never have done so otherwise.
Biogen only had study results from a subset of SMA patients upon approval, but since then has compiled data showing the drug can help multiple types of SMA patients, including those whose disease begins later in life. Spinraza generated $2.1 billion in sales for Biogen last year.
In March 2019, Novartis followed with Zolgensma, a gene therapy meant to provide a similar benefit through a one-time, long-lasting treatment. Just the second gene therapy approved in the U.S., Zolgensma was also cleared for a wide swath of SMA patients — children diagnosed under two years of age, regardless of type. Novartis earned $205 million from Zolgensma in the three months from April to June.
Both treatments have faced significant scrutiny for their high prices. Spinraza costs $750,000 in the first year, and $375,000 each year thereafter. Zolgensma, at $2.1 million for a single infusion, has the highest per-dose price tag of any medicine in the world. Both treatments have to be administered in doctors' offices and in clinics by specialists.
Evrysdi, both cheaper and more conveniently administered, could be a compelling third option. The drug's position is also supported by a broad label granted by the FDA, which reviewed data from one study in infants aged two to seven months and from another trial in children and adults between two and 25 years old.
Given orally by mouth or through a feeding tube, Evrysdi is the only one of the three that can be taken at home — an advantage with new significance since the onset of the coronavirus pandemic. The drug may also be preferred for patients who can't tolerate the spinal taps required of treatment with Spinraza, or who aren't eligible for Biogen's drug or Zolgensma.
Roche's price for Evrysdi is tied to patient's weight, and is capped at $340,000 per year once a patient reaches 44 pounds. For an infant weighing 15 pounds — the average of study participants in one of Roche's trials — the annual cost would be less than $100,000, according to a spokesperson.
"We anticipate that this broad label, convenient oral method of administration and reduced pricing could result in Evrysdi putting significant competitive pressure" on Spinraza, wrote Baird analyst Brian Skorney in a Friday note to clients.
Patients whose families are concerned about interactions within doctors' offices during a pandemic, he wrote, might switch from Spinraza to Roche's drug.
At-home administration is only possible because the FDA judged eye exams for patients on the Roche drug to not be necessary. That was a potential concern given some worrisome signs seen in preclinical testing several years ago, noted RBC Capital Markets analyst Brian Abrahams. No requirement was mentioned in the FDA's statement on Evrysdi's approval.
Upper respiratory tract infections, pneumonia, constipation and vomiting were the most common side effects seen in infants. In older patients they were fever, diarrhea and rash.
Roche licensed Evrysdi from PTC Therapeutics, which will get a royalty on sales of the drug.
Author: Ben Fidler