The U.S. FDA has approved a third treatment for the rare autoimmune condition, Devic's disease. The condition is associated with blindness and paralysis and often coexists with other rheumatic conditions, such as lupus and rheumatoid arthritis.
The U.S. Drug and Food Administration has granted approval to Genentech Inc. for Enspryng (satralizumab-mwge), a treatment for the rare autoimmune condition neuromyelitis optica spectrum disorder (NMOSD), also known as Devic’s disease.
Devic’s disease is a chronic autoimmune condition that often coexists with rheumatic conditions, such as rheumatoid arthritis or systemic lupus erythematosus (SLE). It primarily affects the central nervous system―specifically, inflammation of optic nerves (optic neuritis) and the spinal cord (myelitis). It is rare affecting 0.052 to 0.44 people of every 100,000 worldwide.
Patients with this condition experience repeated attacks in between periods of remission that can last weeks to years. Up until now, the only other approved treatments for the condition included eculizumab (Soliris by Alexion approved in 2019) and inebilizumab-cdon (Uplizna by Viela Bio approved in June), both of which are given through infusion. Prior to the approval of these treatments, a number of existing drugs were used off-label to treat the condition. These included intravenous and oral steroids, and immune-suppressing medications, such as azathioprine or rituximab. The approval of satralizumab-mwge is the third designated treatment for the condition, but it comes with a caveat: it is approved only for adults who are anti-aquaporin-4 (AQP4) antibody-positive.
“Until last year, there were no FDA-approved treatments for patients with this rare, debilitating and sometimes fatal disease. Now there are three,” said Billy Dunn, M.D., director of the Office of Neuroscience in the FDA’s Center for Drug Evaluation and Research in a written statement. “Today’s approval of Enspryng highlights the FDA’s commitment to rapidly advancing safe and effective therapies for NMOSD and other neurological diseases.”
Approximately 50 percent of patients with NMOSD have permanent visual impairment and paralysis. In the United States, it thought affect approximately 4,000-8,000 Americans.
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 satralizumab-mwge 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 satralizumab-mwge 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 satralizumab-mwge 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.
The prescribing information for satralizumab-mwge includes a warning for increased risk of infection, including serious and potentially fatal infections , such as potential reactivation of hepatitis B and tuberculosis. Other warnings and precautions for satralizumab-mwge include elevated liver enzymes, decreased neutrophil counts and hypersensitivity reactions. The most common side effects observed were the common cold (nasopharyngitis), headache, upper respiratory tract infection, inflammation of the lining of the stomach, rash, joint pain, extremity pain, fatigue and nausea. Vaccination with live-attenuated or live vaccines is not recommended during treatment and should be administered at least four weeks before starting satralizumab-mwge.