FDA OKs Satralizumab (Enspryng) for Neuromyelitis Optica Spectrum Disorder

Megan Brooks

August 17, 2020

The US Food and Drug Administration (FDA) has approved satralizumab-mwge (Enspryng, Genentech) for adults with anti-aquaporin-4 (AQP4) antibody-positive neuromyelitis optica spectrum disorder (NMOSD).

NMOSD is a rare debilitating autoimmune inflammatory disease that primarily damages the optic nerve and spinal cord, causing blindness, muscle weakness, and paralysis. NMOSD affects up to 15,000 people in the United States and about 200,000 people worldwide.

Satralizumab is a humanized monoclonal antibody that inhibits interleukin-6 receptor activity, thought to play a key role in the inflammation associated with NMOSD.

Satralizumab is the first subcutaneous treatment for NMOSD that can be administered at home by the patient or caregiver after training by a healthcare provider. The treatment is given every 4 weeks after the initial loading dose.

"For people with NMOSD, relapses can cause devastating, irreversible, and disabling neurological effects," Jeffrey Bennett, MD, PhD, University of Colorado Neurology & Ophthalmology, and investigator for the satralizumab clinical trials, said in a Genentech news release.

"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," Bennett said.

The FDA approved satralizumab based on results of two randomized controlled phase 3 clinical trials (SAkuraStar and SAkuraSky) involving patients with AQP4 antibody-positive NMOSD. The primary endpoint of both studies was the time to first relapse, adjudicated by an independent review committee in the double-blind period.

In the SAkuraStar monotherapy study, 76.5% of satralizumab-treated patients were relapse-free at 96 weeks, compared with 41.1% with placebo. Results from the SAkuraStar study were published in Lancet Neurology.

In the SAkuraSky study, which evaluated satralizumab added to standard immunosuppressant therapy, 91.1% of satralizumab-treated patients were relapse-free at 96 weeks, compared with 56.8% with placebo.

Results from the SAkuraSky study were published in the New England Journal of Medicine.

The most common adverse reactions with satralizumab (incidence ≥ 15%) were nasopharyngitis, headache, upper respiratory tract infection, gastritis, rash, arthralgia, extremity pain, fatigue, and nausea. Full prescribing information is available online.

The company expects satralizumab to be available in the United States in about 2 weeks. They have created the Enspryng Access Solutions team to answer questions, provide product education and injection training, and help families understand insurance coverage and navigate financial assistance options for satralizumab. Their number is 1-844-NSPRYNG (844-677-7964).

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