The U.S. Food and Drug Administration (FDA) has approved Enspryng (satralizumab-mwge) for the treatment of neuromyelitis optica spectrum disorder (NMOSD) in adults with a particular antibody – patients who are anti-aquaporin-4 or AQP4 antibody-positive. NMOSD is a rare autoimmune disease of the central nervous system that mainly affects the optic nerves and spinal cord.
The FDA has granted the approval to Genentech, and Enspryng is the third approved treatment for the disorder. Earlier this year, the FDA approved Uplizna (inebilizumab-cdon) injection for intravenous use from Viela Bio and Soliris (eculizumab) injection from Alexion.
In patients with NMOSD, the body’s immune system mistakenly attacks healthy cells and proteins in the body, most often those in the optic nerves and spinal cord. Individuals with NMOSD typically have attacks of optic neuritis, which causes eye pain and vision loss. Approximately 50 percent of patients with NMOSD have permanent visual impairment and paralysis caused by NMOSD attacks. Estimates vary, but NMOSD is thought to impact approximately 4,000 to 8,000 Americans, according to the FDA.
NMOSD can be associated with antibodies that bind to a protein called aquaporin-4 (AQP4). Binding of the anti-AQP4 antibody appears to activate other components of the immune system, causing inflammation and damage to the central nervous system.
The effectiveness and safety of Enspryng for the treatment of NMOSD was demonstrated in two 96-week clinical studies. The first study included 95 adult patients; 64 of these patients had antibodies against AQP4 (anti-AQP4 positive). During this study, treatment with Enspryng reduced the number of NMOSD relapses by 74 percent in patients who were anti-AQP4 positive compared to treatment with a placebo (inactive treatment).
The second study included 76 adult patients; 52 of these patients were anti-AQP4 positive. During the second study, treatment with Enspryng reduced the number of relapses in patients who were anti-AQP4 positive by 78 percent compared to treatment with a placebo. There was no evidence of a benefit in patients who were anti-AQP4 antibody negative in either trial.
