The U.S. Food and Drug Administration (FDA) today approved Evrysdi (risdiplam) to treat patients two months of age and older with spinal muscular atrophy (SMA), a rare and often fatal genetic disease affecting muscle strength and movement. This is the second drug and the first oral drug approved to treat this disease.
The efficacy of Evrysdi for the treatment of patients with infantile-onset and later-onset SMA was evaluated in two clinical studies. The infantile-onset SMA study included 21 patients who had an average age of 6.7 months when the study began. In that open-label study, efficacy was established based on the ability to sit without support for at least five seconds and survival without permanent ventilation. After 12 months of treatment, 41% of patients were able to sit independently for more than five seconds, a meaningful difference from the natural progression of the disease because almost all untreated infants with infantile-onset SMA cannot sit independently. After 23 or more months of treatment, 81% of patients were alive without permanent ventilation, which is a noticeable improvement from typical disease progression without treatment.
The most common side effects of Evrysdi include fever, diarrhea, rash, ulcers of the mouth area, joint pain (arthralgia) and urinary tract infections. Patients with infantile-onset SMA had similar side effects as individuals with later-onset SMA. Additional side effects for the infantile-onset population include upper respiratory tract infection, pneumonia, constipation and vomiting. Patients should avoid taking Evrysdi together with drugs that are multidrug and toxin extrusion substrates because Evrysdi may increase plasma concentrations of these drugs.
**Evrysdi is a product of the SMA collaboration between PTC, the SMA Foundation, and Roche**