The Food and Drug Administration (FDA) has approved Enspryng (satralizumab-mwge; Genentech) for the treatment of neuromyelitis optica spectrum disorder (NMOSD) in adult patients who are anti-aquaporin-4 (AQP4) antibody positive.

Satralizumab-mwge is a humanized monoclonal antibody that targets the interleukin-6 (IL-6) receptor, which is believed to be a key driver of NMOSD, a debilitating autoimmune condition of the central nervous system. The approval was based on data from two phase 3, placebo-controlled studies, SAkuraStar (N=95) and SAkuraSky (N=76), which evaluated the safety and efficacy of satralizumab-mwge as monotherapy and in combination with baseline immunosuppressants, respectively.

In the SAkuraStar study, the time to the first Clinical Endpoint Committee (CEC)-confirmed relapse (primary end point) was found to be significantly longer in patients treated with satralizumab-mwge compared with those who received placebo (risk reduction 55%; hazard ratio [HR] 0.45; P =.0184).  In the anti-AQP4 antibody positive population, there was a 74% reduction in risk (HR 0.26; P =.0014).

In the SAkuraSky study, the time to the first CEC-confirmed relapse was significantly longer in the satralizumab-mwge arm vs the placebo arm (risk reduction 62%; HR 0.38; P =.0184).  In the anti-AQP4 antibody positive population, there was a 78% reduction in risk (HR 0.22; P =.0143).

No evidence of benefit was observed in either study among the anti-AQP4 antibody negative patient population.

With regard to safety, the most common treatment-emergent adverse reactions reported in trials included nasopharyngitis, headache, upper respiratory tract infection, gastritis, rash, arthralgia, extremity pain, fatigue, and nausea. Additionally, treatment with satralizumab-mwge may increase the risk for serious infections and has also been shown to elevate liver enzymes and decrease neutrophil counts.

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Enspryng is supplied in single-dose 120mg/mL prefilled syringes and is intended for patient self-administration by subcutaneous injection. “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,” said Professor Jeffrey Bennett, University of Colorado Neurology & Ophthalmology, and investigator for the Enspryng pivotal clinical trials.

The product will be available in 2 weeks.

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  1. FDA approves Genentech’s Enspryng for neuromyelitis optica spectrum disorder. Accessed August 17, 2020.
  2. Enspryng [package insert]. South San Francisco, CA: Genentech; 2020.