TOKYO--( BUSINESS WIRE )-- Chugai Pharmaceutical Co., Ltd. (TOKYO: 4519) announced new longer-term efficacy and safety data for Enspryng ® [generic name: satralizumab (genetical recombination)], a pH-dependent binding humanized anti-IL-6 receptor monoclonal antibody created by Chugai. The data show Enspryng has a favourable benefit:risk profile and is effective in reducing relapses over four years of treatment in people with anti-aquaporin-4 antibody (AQP4-IgG) seropositive neuromyelitis optica spectrum disorder (NMOSD), a rare debilitating disease that affects the central nervous system.