RARE Daily

FDA Approves Genentech’s Enspryng for NMOSD

August 17, 2020

Rare Daily Staff

The U.S. Food and Drug Administration approved Genentech’s Enspryng as the first and only subcutaneous treatment for adults living with anti-aquaporin-4 (AQP4) antibody positive neuromyelitis optica spectrum disorder.

It is the third FDA approval for the rare autoimmune disease in a little more than a year, as Enspryng will compete with Alexion’s Soliris and Viela Bio’s newly approved Uplinza.

Neuromyelitis optica spectrum disorder (NMOSD) is a rare, lifelong, and debilitating autoimmune disease of the central nervous system that primarily damages the optic nerves and spinal cord, causing blindness, muscle weakness and paralysis. People with NMOSD experience unpredictable, severe relapses directly causing cumulative, permanent, neurological damage and disability. In some cases, relapse can result in death. The disease is most common among non-Caucasian women in their 30s and 40s.

NMOSD is commonly associated with pathogenic antibodies (AQP4-IgG) that target and damage a specific cell type, called astrocytes, resulting in inflammatory lesions of the optic nerves, spinal cord, and brain. AQP4-IgG antibodies are detectable in the blood serum of about two-thirds of NMOSD patients.

Although most cases of NMOSD can be confirmed through a diagnostic test, people living with the condition are still frequently misdiagnosed with multiple sclerosis. This is due to overlapping characteristics of the two disorders, including a higher prevalence in women, similar symptoms, and the fact that both are relapse-based conditions.

“Today’s FDA approval of Enspryng, the first subcutaneous NMOSD treatment using novel recycling antibody technology, builds upon the work we’ve done in multiple sclerosis with Ocrevus to develop first-in-class medicines and further the scientific understanding of neuroimmunological diseases,” said Levi Garraway, Genentech’s chief medical officer and head of Global Product Development.

Enspryng (satralizumab-mwge) is a humanized monoclonal antibody designed Chugai, a member of the Roche group as is Genentech. It is the only approved therapy for NMOSD designed to target and inhibit cytokine IL-6 receptor activity, believed to play a key role in the inflammation associated with NMOSD. The treatment was designed to allow for longer duration of antibody circulation and subcutaneous dosing every four weeks. It can be self-administered or given by a caregiver in the home.

“For people with NMOSD, relapses can cause devastating, irreversible and disabling neurological effects,” said Professor Jeffrey Bennett, University of Colorado Neurology & Ophthalmology, and investigator for the Enspryng pivotal clinical trials. “Having an approved therapy that can be administered subcutaneously in the home and has demonstrated an impact on the frequency of relapses is an important advancement for patients.”

“After years of dedicated effort and collaboration, the FDA approval of Enspryng exemplifies how patients, industry, and academia can find solutions together,” said Victoria Jackson, founder, The Guthy-Jacson Charitable Foundation and mother of a daughter with NMOSD.

The FDA approval is based on results from two randomized controlled phase 3 clinical trials, the SAkuraStar and SAkuraSky studies, in which Enspryng demonstrated robust and sustained efficacy and a favorable safety profile in adults with AQP4 antibody positive NMOSD. 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, which has commonly been used to manage NMOSD symptoms associated with relapses.

The most common adverse reactions with Enspryng were nasopharyngitis, headache, upper respiratory tract infection, gastritis, rash, arthralgia, extremity pain, fatigue and nausea.

Enspryng, which is already approved in Japan, Canada, and Switzerland, and will be available in the United States in two weeks.

Enspryng has been designated as an orphan drug in the United States, Europe and Japan. The FDA also granted it Breakthrough Therapy designation for the treatment of NMOSD.

Photo: Levi Garraway, chief medical officer and head of global product development for Genentech

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