FDA Approves Third Drug for NMOSD

The FDA Monday approved satralizumab for the treatment of neuromyelitis optica spectrum disorder (NMOSD) in adults with a particular antibody—patients who are anti-aquaporin-4 (AQP4) positive.

Neuromyelitis optica disorders are rare autoimmune conditions that involve severe axonal damage, primarily to the optic nerve and the spinal cord. Patients experience life-threatening symptoms, including loss of vision, paralysis, and bowel and bladder dysfunction.

The approval was granted to Genentech, which will sell the drug under the name Enspryng. It is the third treatment for the disease approved by the FDA in the past year. The 2 other drugs approved for NMOSD are eculizumab and inebilizumab.

About 50% of patients with NMOSD have permanent visual impairment and paralysis; the disorder is believed to affect about 4000 to 8000 Americans.

Binding of the anti-AQP4 antibody appears to activate other components of the immune system, causing inflammation and damage to the central nervous system.

“Today’s approval of Enspryng highlights the FDA’s commitment to rapidly advancing safe and effective therapies for NMOSD and other neurological diseases,” said Billy Dunn, MD, director of the Office of Neuroscience in the FDA’s Center for Drug Evaluation and Research, in a statement.

The effectiveness and safety of satralizumab were 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). Satralizumab treatment cut the number of NMOSD relapses by 74% in these patients compared with a placebo.

The second study included 76 adult patients; 52 of these patients were anti-AQP4 positive. Satralizumab cut the number of relapses in patients who were anti-AQP4 positive by 78% compared with treatment with a placebo.

In both trials, there was no evidence of a benefit if patients did not have the AQP4 antibody.

As with other biologics, the drug carries a warning for increased risk of infection. Other precautions include elevated liver enzymes, decreased neutrophil counts, and hypersensitivity reactions. The most common adverse effects observed were nasopharyngitis, headache, upper respiratory tract infection, inflammation of the lining of the stomach, rash, joint pain, extremity pain, fatigue, and nausea.

Satralizumab received a fast track designation and an orphan drug designation.