Eculizumab or ravulizumab treatment effect in people with neuromyelitis optica spectrum disorder: a plain language summary of three studies.

What is this summary about?: Neuromyelitis optica spectrum disorder (NMOSD for short) is a rare autoimmune health condition, meaning that the body's natural defense system (the immune system) attacks the body's own tissues. This summary describes NMOSD and the results of three studies of the effects of treatment with two medicines called eculizumab and ravulizumab. Eculizumab and ravulizumab are approved to treat people with a type of NMOSD called AQP4-Ab+ NMOSD. The three studies included in this summary are the PREVENT and CHAMPION-NMOSD clinical studies and a study done in everyday clinical practice in Japan.

What are the key conclusions from these studies?: The PREVENT study was a phase 3 study (a large study testing safety and effectiveness of a treatment before it is approved) with three parts. The PREVENT main study compared eculizumab to a placebo (a treatment with no active ingredients, used to test how well a new treatment works). A long-term follow-up study assessed the safety and effectiveness of eculizumab over time, without a placebo group. Another long-term follow-up focused on people taking eculizumab alone, without other immunosuppressive treatments. The CHAMPION-NMOSD study was another phase 3 study testing ravulizumab, a treatment based on eculizumab but given less often, using the placebo group from the PREVENT study for comparison. A daily clinical practice study with eculizumab in Japan looked at how eculizumab works in everyday medical practice (outside of controlled clinical trials) after the medication was already approved. The studies found eculizumab and ravulizumab to be safe and effective for preventing relapses in AQP4-Ab+ NMOSD. More than 95% of people treated with these medicines stayed relapse-free during the months or years of the studies follow-up periods. Most people reported side effects that were mild or moderate. The most common side effects were headache, runny nose or sore throat (nasopharyngitis), and infections in the upper respiratory system. The daily practice study confirmed that eculizumab works well in everyday medical practice.

What do the findings of the study mean?: These studies suggest that eculizumab and ravulizumab are safe and effective treatments for people with AQP4-Ab+ NMOSD. Eculizumab may help reduce or stop the need for other treatments that weaken the immune system (immunosuppressive therapies). These treatments help people maintain their ability to carry out daily activities and their quality of life.