Satralizumab-mwge (Enspryng) has received the US FDA approval for the treatment of adults with anti-aquaporin-4 (AQP4) antibody-positive neuromyelitis optica spectrum disorder (NMOSD), announced Genentech.
NMOSD is a rare, lifelong and debilitating autoimmune disorder of the central nervous system, often misdiagnosed as multiple sclerosis, that primarily damages the optic nerves and spinal cord, causing blindness, muscle weakness and paralysis.
Satralizumab is a humanised monoclonal antibody designed to target and inhibit interleukin-6 (IL-6) receptor activity, that play a key role in the inflammation associated with NMOSD.The subcutaneous therapy was designed using novel recycling antibody technology, which, compared to conventional technology, allows for a longer duration of antibody circulation and subcutaneous dosing every four weeks.
Relapses can cause devastating, irreversible and disabling neurological effects, for people with NMOSD. Satralizumab can be administered in the home by a person living with NMOSD or a caregiver following training from a healthcare provider. The treatment needs to be administered every four weeks after an initial loading dose.
The approval was based on results from two randomised controlled phase III clinical trials, the SAkuraStar and SAkuraSky studies, in which satralizumab demonstrated robust and sustained efficacy and a favourable safety profile in adults with AQP4 antibody positive NMOSD, said the company.
Results were sustained for 96 weeks, significantly reducing the risk of relapse compared with placebo as a monotherapy and when used concurrently with baseline immunosuppressant therapy (IST), which has commonly been used to manage NMOSD symptoms associated with relapses.
In the SAkuraStar monotherapy study’s AQP4 antibody positive subgroup, 76.5% of satralizumab-treated patients were relapse-free at 96 weeks, compared to 41.1% with placebo. In the SAkuraSky study, which evaluated satralizumab when used concurrently with baseline IST, 91.1% of satralizumab-treated AQP4 antibody positive subgroup patients were relapse-free at 96 weeks, compared to 56.8% with placebo.
The most common adverse reactions with satralizumab (incidence ≥ 15%) were nasopharyngitis, headache, upper respiratory tract infection, gastritis, rash, arthralgia, extremity pain, fatigue and nausea.