Rare Daily Staff

The U.S. Food and Drug Administration has accepted Genentech’s application for the approval of its experimental therapy satralizumab to treat neuromyelitis optica spectrum disorder, a rare, debilitating central nervous system disease.

The European Medicines Agency has also validated the company’s application to market satralizumab, granting it Accelerated Assessment. The FDA and EMA are expected to act on the applications in 2020.

Neuromyelitis optical spectrum disorder (NMOSD) is an autoimmune disease that primarily damages the optic nerves and the 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. Although most cases of NMOSD can be confirmed through a diagnostic test, people living with the condition are still frequently misdiagnosed with multiple sclerosis.

If approved, satralizumab would offer an alternative approach to Alexion’s Soliris, now the only approved therapy for the condition. Satralizumab targets the interleukin-6 (IL-6) receptor. IL-6 is thought to be a key driver of the disease, triggering the inflammation cascade and leading to damage and disability. Satralizumab can be self-administered subcutaneously every four weeks.

“People living with NMOSD experience unpredictable relapses that can cause permanent neurological damage, and although there have been significant strides recently in understanding the disease, more approved options are needed with different treatment approaches,” said Levi Garraway, chief medical officer and head of Global Product Development. “Satralizumab has shown robust efficacy sustained for 96 weeks and significantly reduced the risk of relapse across a broad patient population, while offering self-administered subcutaneous dosing every four weeks.”

The satralizumab applications are based on positive results from two phase 3 studies evaluating the efficacy and safety of satralizumab as a monotherapy and in combination with baseline immunosuppressant therapy.

In the of study of satralizumab as a monotherapy, it achieved a 55 percent reduction in the risk of relapses compared to placebo in the overall study population of aquaporin-4 antibody (AQP4-IgG) seropositive and seronegative patients. Satralizumab achieved a 74 percent reduction in the larger subgroup of AQP4-IgG seropositive patients, who tend to experience a more severe disease course. In the overall satralizumab-treated population, 76.1 percent were relapse-free at 48 weeks, and 72.1 percent relapse-free at 96 weeks, compared to 61.9 percent and 51.2 percent with placebo, respectively. Data from the AQP4-IgG seropositive subgroup showed that 82.9 percent were relapse-free at 48 weeks and 76.5 percent relapse-free at 96 weeks when treated with satralizumab, compared to 55.4 percent at 48 weeks and 41.1 at 96 weeks for those treated with placebo.

The data showed a 62 percent reduction in the risk of relapses compared to placebo in the overall study population when used in combination with baseline immunosuppressant therapy, and a 79 percent reduction in the risk of relapses in AQP4-IgG seropositive patients. In the overall satralizumab-treated population, 88.9 percent were relapse-free at 48 weeks, and 77.6 percent were relapse-free at 96 weeks, compared to 66.0 percent at 48 weeks and 58.7 percent at 96 weeks for those treated with placebo.

Overall, the proportion of patients with serious adverse events was similar between the satralizumab and placebo treatment groups in both studies. A lower rate of infections (including serious infections) was observed in patients treated with satralizumab compared with the placebo group.

The FDA previously granted Breakthrough Therapy designation to satralizumab for the treatment of NMOSD in December 2018.

Photo: Levi Garraway, chief medical officer and head of Global Product Development

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