Evrysdi Approved to Treat Spinal Muscular Atrophy

August 7, 2020 – The U.S. FDA has approved EvrysdiTM (risdiplam), manufactured by Genentech, to treat spinal muscular atrophy (SMA) in patients who are at least two months old.

SMA is a genetic disorder that leads to weakened, atrophied muscles due to the loss of motor neurons. These neurons are necessary to control muscle movement. As they die off, muscle tissue begins to waste away and patients suffer a loss of mobility. Usually, the effects are worse in the muscles at the central part of the body, rather than distant muscles such as those in the arms and legs. SMA can manifest before birth and through early adulthood, though it’s most commonly diagnosed at birth or during the first few months of life. Patients whose SMA is evident before early childhood have more severe disease and shortened life expectancies.

In clinical trials, 41% of infants treated with Evrysdi were able to sit without support for at least five seconds, a motor milestone not typically seen in the natural course of SMA. In addition, 90% of infants were alive without permanent ventilation at one year of treatment and reached at least 15 months of age. With untreated infantile-onset SMA, infants are not ordinarily able to sit independently, with only 25% expected to survive without permanent ventilation beyond the age of 14 months. Children and adults who received Evrysdi experienced a clinically meaningful and statistically significant improvement in motor function at one year of treatment compared to placebo. Evrysdi also improved survival without permanent ventilation at 12 and 23 months of treatment compared to the natural course of SMA.

Recommended dosing is based on weight. Evrysdi is administered via oral syringe once daily after a meal at approximately the same time each day. Patients should drink water immediately after to help ensure the full dose is swallowed. If the patient is unable to swallow, Evrysdi can be administered via nasogastric or gastrostomy tube. The tube should be flushed with water after the dose is given.

Genentech has launched Evrysdi at a wholesale acquisition cost (WAC) of $11,170.43 per 80mL bottle.