Japanese drug manufacturer Chugai Pharmaceutical has announced the results of the SAkuraSky Study, a global Phase III clinical study of satralizumab, an anti-IL6 receptor humanised recycling antibody for the treatment of neuromyelitis optica spectrum disorder (NMOSD).
NMOSD is an autoimmune disease of the central nervous system that results in inflammatory lesions in the optic nerves and spinal cord, causing permanent neurologic disorders.
Symptoms of NMOSD include visual impairment, motor disability, loss of quality of life, and in some cases death.
Aquaporin-4 antibodies (AQP4-IgG) detected in two-thirds of NMOSD patients target and damage a specific central nervous cell type called astrocytes.
Satralizumab is an anti-IL-6 receptor recycling antibody expected to suppress relapse of NMOSD by inhibiting IL-6 signal transduction.
The Phase III multicentre, randomised, double-blind, placebo-controlled study evaluated the efficacy and safety of satralizumab added to baseline therapy in NMOSD patients. For the study, 83 male and female patients aged 13-73 were randomised.
The primary endpoint was the time to first protocol-defined relapse (PDR) adjudicated by an independent review committee in the double-blind period.
Chugai said that satralizumab added to baseline immunosuppressant therapy significantly reduced the risk of relapse in patients with NMOSD and showed a well-tolerated safety profile when added to baseline therapy.
The company said that in the SAkuraSky Study, only eight of 41 patients (20%) treated with satralizumab in combination with baseline immunosuppressant therapy experienced a PDR compared to 18 of 42 patients (43%) treated with placebo in combination with baseline therapy.
It said that 89%, 78% and 74% of patients on satralizumab in combination with baseline therapy were found to be relapse-free at weeks 48, 96 and 144 compared to 66%, 59% and 49% with placebo in combination with baseline therapy.
According to the company, the proportion of serious adverse events was similar between the satralizumab and placebo treatment groups.
Chugai said that the primary endpoint was achieved with satralizumab as an add-on therapy to baseline immunosuppressant treatment or as monotherapy in two global Phase III clinical studies in NMO and NMOSD patients.
Satralizumab is designated as an orphan drug for the treatment of NMO and NMOSD in Japan, Europe and the US and was granted breakthrough therapy designation by the US Food and Drug Administration in December 2018.