The US Food and Drug Administration (FDA) on Thursday authorised the marketing of Soliris (eculizumab) injection for intravenous use for the treatment of neuromyelitis optica spectrum disorder (NMOSD) in adult patients who are anti-aquaporin-4 (AQP4) antibody positive, under its priority review.

NMOSD is a rare autoimmune disease of the central nervous system that mainly affects the optic nerves and spinal cord.

The agency granted the approval of Soliris to Alexion Pharmaceuticals (NASDAQ:ALXN).

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 of Soliris for treating NMOSD was demonstrated in the company's clinical study of 143 patients with NMOSD who had antibodies against AQP4 (anti-AQP4 positive) and who were randomised to receive either Soliris treatment or placebo. Soliris reduced the number of NMOSD relapses by 94% over the 48-week trial.

Soliris is available only through a restricted programme under a Risk Evaluation and Mitigation Strategy (REMS). Prescribers must enrol in the REMS programme. The drug must be dispensed with the US FDA-approved patient Medication Guide that provides important information about the drug's uses and risks.