FDA Approves Risdiplam--The First Oral At-Home Treatment--for Spinal Muscular Atrophy

The Food and Drug Administration (FDA) has approved risdiplam (Evrysdi; Genentech, South San Francisco, CA) for treatment of spinal muscular atrophy (SMA) in adults and children age 2 months or more. Risdiplam is administered as a liquid, taken by mouth or via a feeding tube in individuals who need parenteral nutrition. Risdiplam is expected to be available in the US within 2 weeks for direct delivery to the home through Accredo Health Group Inc., an Express Scripts specialty pharmacy

In the FIREFISH (NCT02913482) clinical trial, treatment with risdiplam resulted in meaningful improvements in motor function in individuals with type 1 SMA. Infants with type 1 SMA, developed the ability to sit without support for at least 5 seconds, a key motor milestone not typically seen in the natural course of the disease. Survival without permanent ventilation at 12 and 23 months was also improved compared with natural history.

In the SUNFISH (NCT02908685) clinical trial, children and adults with type 2 or 3 SMA who were treated with risdiplam had statistically significant and clinically meaningful motor function improvements  on the Motor Function Measure-32 (MFM-32) total score (1.36 points [95% CI: 0.61, 2.11]) compared with those treated with placebo (-0.19 points [95% CI: -1.22, 0.84], P=.0156).

“Given the majority of people with SMA in the US remain untreated, we believe Evrysdi, with its favorable clinical profile and oral administration, may offer meaningful benefits for many living with this rare neurologic disease,” said Levi Garraway, MD, PhD, chief medical officer and head of Global Product Development. “

“Throughout their lives, many people with SMA may lose their ability to perform critical movements, which can impact the ability to independently participate in aspects of daily life and even be life altering,” said Kenneth Hobby, president of Cure SMA. “The approval of Evrysdi is an eagerly awaited milestone for our community. We appreciate Genentech’s commitment to reflecting the full scope of the real-world SMA population in their clinical trial program and developing a treatment that can be administered at home.”  

Risdiplam is a gene-splicing modulator that increases production of survival of motor neuron protein (SMN), needed for survival of motor neurons. Risdiplam was found safe as well as effective. The most common adverse reactions were fever, diarrhea, and rash in all participants; infants also experienced upper respiratory tract infection, pneumonia, constipation, and vomiting. No treatment-related adverse events led to withdrawal from either study.