ENSPRYNG Achieves 68% Reduction in MOGAD Relapses in Pivotal Phase III Trial
Key Insights
Roche's ENSPRYNG (satralizumab) demonstrated a 68% reduction in relapse risk compared to placebo in the Phase III METEOROID study for myelin oligodendrocyte glycoprotein antibody-associated disease (search) (MOGAD (search)).
The study met its primary endpoint with 87% of patients on ENSPRYNG remaining relapse-free at 48 weeks compared to 67% on placebo, representing the first potential approved treatment for this rare autoimmune disease.
Secondary endpoints showed significant reductions in CNS inflammation markers and rescue therapy use, with a 79% reduction in active MRI lesions and 73% fewer patients requiring rescue treatments.
Roche announced breakthrough results from the Phase III METEOROID study showing that ENSPRYNG (satralizumab) reduced the risk of new relapses by 68% compared to placebo in adults and adolescents with myelin oligodendrocyte glycoprotein antibody-associated disease (search) (MOGAD (search)). The study met its primary endpoint, measuring time from randomization to first MOGAD relapse during the double-blind treatment period (p=0.0025). Results were presented at the 2026 American Academy of Neurology Annual Meeting in Chicago.
First Potential Treatment for Rare Autoimmune Disease
MOGAD (search) is a rare autoimmune disease of the central nervous system that preferentially affects the optic nerves but can also impact the brain and spinal cord. The disease affects an estimated 0.51 to 3.42 per 100,000 people and is characterized by unpredictable attacks causing severe and debilitating symptoms including vision loss, pain, fatigue, numbness, and cognitive dysfunction.
"MOGAD (search) is a rare autoimmune disease that can attack the optic nerves, brain and spinal cord and cause severe and unpredictable relapses, resulting in accumulating neurological damage, vision loss and disability. Currently, there are no approved treatment options for this debilitating disease," said Michael Levy, MD, PhD, Associate Professor at Harvard School and Massachusetts General Hospital.
Robust Efficacy Across Multiple Endpoints
The primary endpoint demonstrated that 87% of patients receiving ENSPRYNG were relapse-free compared to 67% on placebo at 48 weeks, with treatment response observed as early as 8 weeks. The treatment effect remained consistent across subgroups including age, sex, race, and background therapy use.
ENSPRYNG also achieved significant results in key secondary endpoints. The drug reduced the annualized relapse rate by 66% (p=0.0030), a critical measure since disability in MOGAD (search) relates directly to acute relapses. Additional secondary endpoints showed ENSPRYNG's potential to reduce central nervous system inflammation and dependence on rescue therapies.
The study demonstrated a 79% reduction in the annualized rate of active lesions on MRI across the optic nerves, brain and spinal cord, and a 73% lower proportion of patients requiring rescue therapy compared to placebo (p=0.0026 and p=0.0024, respectively). A numerical 17% reduction in annualized inpatient hospitalizations was also observed (p=0.7528).
Established Safety Profile
No new safety signals emerged during the METEOROID study, with the safety profile consistent with more than a decade of ENSPRYNG clinical trial and post-approval experience in aquaporin-4 immunoglobulin (AQP4-IgG) seropositive neuromyelitis optica spectrum disorder (search) (NMOSD (search)). Common adverse events (≥5%) included injection-related reactions (16%), influenza (9%), arthralgia (9%), back pain (9%), sinusitis (7%) and diarrhea (6%).
Treatment interruption rates remained low, with 6% of ENSPRYNG patients and 5% of placebo patients experiencing adverse events leading to temporary treatment interruption. One fatality occurred that was unrelated to treatment, and no serious adverse events were considered treatment-related.
Study Design and Mechanism of Action
METEOROID was a randomized, double-blind, placebo-controlled, multicenter study enrolling adults and adolescents 12 years and older with MOGAD (search). Participants were randomized 1:1 to receive ENSPRYNG (60 mg, 120 mg or 180 mg based on body weight) or placebo, administered subcutaneously at 0, 2 and 4 weeks, then every 4 weeks thereafter.
ENSPRYNG is a humanized monoclonal antibody targeting interleukin-6 (IL-6) receptor activity, developed by Chugai (search), a Roche Group member. The drug utilizes novel recycling antibody technology enabling sustained IL-6 inhibition compared to conventional approaches.
Patients with MOGAD (search) have elevated IL-6 levels in cerebrospinal fluid and serum, promoting T-cell-mediated inflammation, stimulating autoantibody production from plasma cells, and disrupting the blood-brain barrier. By blocking IL-6 signaling, ENSPRYNG potentially reduces disease-related antibody production, suppresses inflammatory T cells, and restores blood-brain barrier integrity.
Regulatory Path Forward
"The remarkable 68% reduction in relapses seen in the METEOROID study has the potential to redefine the standard of care and to deliver the first and only approved treatment for this debilitating rare disease," said Levi Garraway, MD, PhD, Roche's Chief Medical Officer and Head of Global Product Development.
The METEOROID data will be submitted to regulatory authorities globally. ENSPRYNG currently holds orphan drug designation from the FDA for MOGAD (search) and is approved in approximately 90 countries for AQP4-IgG seropositive NMOSD (search), with more than 9,000 patients treated.
The drug offers at-home self-administration flexibility through subcutaneous injections following healthcare provider training and approval. Treatment begins with a loading dose of 120 mg administered every other week for three injections, followed by maintenance doses every four weeks.