The European Commission (EC) has approved Chugai Pharmaceutical’s Enspryng (satralizumab) to treat anti-aquaporin-4 antibody (AQP4-IgG) seropositive neuromyelitis optica spectrum disorder (NMOSD).

The approval is for adults and adolescents aged 12 years and above.

Enspryng can be used alone or combined with immunosuppressive therapy. It is the first NMOSD therapy approved for subcutaneous use at home after suitable training.

The drug is a humanised monoclonal antibody developed to inhibit the interleukin-6 (IL-6) receptor, a key driver of the inflammation related to NMOSD.

Chugai, which is a Roche Group member, designed the drug with recycling antibody technology, which allows longer retention in the bloodstream. This facilitates a dosing regimen of every four weeks.

Currently, the drug has approval in 54 countries, including the US, Canada, Japan, China and the EU.

Chugai Pharmaceutical president and CEO Dr Osamu Okuda said: “Enspryng is the first approved therapeutic antibody for which our proprietary recycling antibody technology was applied.

“We are confident that Enspryng will meaningfully contribute to improving the treatment of people with NMOSD, by fitting into their day-to-day lives.”

The EC approved Enspryng after reviewing data from Phase III SAkuraStar and SAkuraSky clinical trials, where the drug demonstrated consistent efficacy in decreasing the risk of relapse in patients with AQP4-IgG seropositive NMOSD.

The primary endpoint of both trials was time to first protocol-defined relapse.

Among NMOSD patients, AQP4-IgG are present in nearly 70-80% and cause more severe disease course than those with no AQP4-IgG antibodies.

The SAkuraStar trial assessed the safety and efficacy of Enspryng monotherapy.

In the AQP4-IgG seropositive subgroup, 83% of subjects who received the drug were relapse-free at 48 weeks versus 55% on placebo. At 96 weeks, 77% on Enspryng remained relapse-free when compared to 41% on placebo.

Data from the SAkuraSky trial of the drug plus baseline immunosuppressive therapy showed that overall, 92% of AQP4-IgG seropositive subjects treated with the combination remained relapse-free at 48 and 96 weeks versus 60% and 53% on placebo, respectively.

The drug had an encouraging safety and tolerability profile in both trials.