Chugai Pharmaceutical Co. Ltd.'s nerve disease drug satralizumab significantly reduced relapses in patients suffering from an autoimmune disease of the nervous system, a late-stage study showed.

The phase 3 trial, called SAkuraSky, enrolled 83 patients with neuromyelitis optica spectrum disorder, or NMOSD — a rare, lifelong and debilitating autoimmune disease of the central nervous system. NMOSD is characterized by inflammatory lesions in the optic nerves and spinal cord, leading to visual impairment, motor disability and in some cases, death. The disease has no approved treatments.

Patients received, in addition to immunosuppressive therapy, either satralizumab or placebo. Chugai said the mean treatment duration was about two years, with patients in the placebo group transferred to satralizumab therapy after 26 reported relapses.

SAkuraSky's main goal measured for risk of relapse — NMOSD attacks leading to accumulating neurological damage and disability. Satralizumab was shown to reduce relapse risk by 62%, achieving the study's main goal.

Further, the proportion of relapse-free patients in the satralizumab group was 88.9% at week 48 and 77.6% at week 96. With placebo, the relapse-free proportion was 66% at week 48 and 58.7% at week 96.

Satralizumab also showed a favorable safety profile, with similar reports of serious adverse events between satralizumab and placebo groups. No death or anaphylactic reactions were observed.

The Tokyo-based pharmaceutical company presented the data from SAkuraSky at the Congress of European Committee for Treatment and Research in Multiple Sclerosis in Berlin.