FDA approves Enspryng for thyroid eye disease treatment

SOUTH SAN FRANCISCO - The U.S. Food and Drug Administration has granted approval for Enspryng (satralizumab-mwge), a subcutaneous treatment for thyroid eye disease, making it the first at-home administration option for the condition. The approval stems from two Phase III clinical trials, SatraGO-1 and SatraGO-2. Although SatraGO-1 did not meet its primary efficacy endpoint at week 24, SatraGO-2 showed a 52.9% proptosis response rate in the Enspryng group versus 23.4% in the placebo group.

Additionally, Enspryng led to a 60.7% reduction in diplopia among active thyroid eye disease patients, compared to 25.8% in the placebo group. The studies involved 258 patients from 19 countries, with the primary endpoint measuring at least a 2 mm decrease in proptosis from baseline at week 24. Enspryng, an anti-IL-6R monoclonal antibody, can be administered every four weeks by patients or caregivers after training by a healthcare provider.

The condition affects around 155 people in every 100,000 in the U.S. and can lead to eye bulging, double vision, and vision-threatening complications. This marks the second indication for Enspryng, which was previously approved for neuromyelitis optica spectrum disorder in 2020. The drug is currently approved in about 90 countries for NMOSD, and the FDA granted priority review for its use in myelin oligodendrocyte glycoprotein antibody-associated disease in September, with an approval decision expected in January 2027. Genentech, a member of the Roche Group, developed Enspryng.