FDA alert

FDA Approves Biosimilar Treatment for Patients With Multiple Sclerosis

Jessica Ganga

In August 2023, the FDA approved the first biosimilar to natalizumab—natalizumab-sztn—for the treatment of adults with relapsing forms of multiple sclerosis (MS), according to an FDA news release.

The approval of natalizumab-sztn is based on evidence that presented no clinically meaningful differences between natalizumab-sztn and natalizumab in terms safety and effectiveness.

“Biosimilar medications offer additional effective treatment options that have the potential to increase access for people living with relapsing forms of multiple sclerosis,” Paul R. Lee, MD, PhD, director of the Division of Neurology in the FDA’s Center for Drug Evaluation and Research, said in the news release. “Today’s approval could have a meaningful impact for patients managing their disease.”

Natalizumab-sztn was approved to treat multiple relapsing forms of MS including:

  • Clinically isolated syndrome (single first occurrence of MS symptoms)
  • Relapsing-remitting disease (occurs when patients have episodes of new neurological symptoms followed by periods of stability)
  • Active secondary progressive disease (patients experience gradual disability worsening with continued relapses following a relapsing-remitting course)

Additionally, the treatment contains a boxed warning about the risk of developing progressive multifocal leukoencephalopathy (PML), which is a viral infection of the brain that may lead to death or severe disability. Its risk factors include the presence of anti-JCV antibodies, longer duration of therapy and prior use of immunosuppressants. The risk of patients being infected with PML makes the treatment available only through a restricted drug distribution program.

Further, the most common adverse effects are headache and fatigue, joint pain, urinary tract infection, lower respiratory tract infection, gastroenteritis, vaginitis, depression, pain in extremity, abdominal discomfort, diarrhea, and rash.



FDA approves first biosimilar to treat multiple sclerosis. News release. US Food and Drug Administration; August 24, 2023. Accessed November 14, 2023.