Natalizumab Infusion Reports Strong Safety Profile, Rarely Causes Adverse Events in Relapsing MS

Yujie Wang, MD

Data from a recent study suggest that natalizumab (Tysabri; Biogen) infusion-related adverse events (AEs) appear to be rare, generally mild, and occur only during the first few infusions in patients with relapsing-remitting multiple sclerosis (RRMS).

Findings from the study were presented at the Americas Committee for Treatment and Research in Multiple Sclerosis (ACTRIMS) Forum 2021, February 25-27, by Yujie Wang, MD, University of Washington Medical Center, and colleagues.

“Natalizumab is an approved treatment for [RRMS] since 2006. Though infusion reactions are usually mild, occur typically within the first six months of treatment and clinically relevant infusion reactions are extraordinarily rare, there is a mandatory 1-hour post-infusion monitoring after each dose, independent of treatment duration. This has posed concerns of unnecessarily increasing SARS-CoV2 exposure risks for patients and staff,” Wang and colleagues wrote.

Wang et al conducted a retrospective cohort study of 333 patients with RRMS receiving natalizumab at the University of Washington’s MS center infusion suite from July 2012 to September 2020. They investigated the frequency, severity, nature, and timing of infusion reactions that occurred during infusion and 1-hour post-infusion monitoring. They also analyzed data from patients such as details of natalizumab treatment and presence of anti-natalizumab antibody in serum.

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The patients had a mean age of 41 years (standard deviation [SD], 12) and 87 (26%) were men. Altogether, the patients underwent 9862 infusions of natalizumab. The mean number of infusions was 27 per patient, with a range of 1 to 174.

A total of 33 infusion-related AEs (0.34% of infusions) were recorded in 26 patients (7.8%). The majority of AEs occurred during infusion (77%) rather than the 1-hour post-infusion monitoring, and 92% of AEs occurred within the first 6 months of treatments.

Wang and colleagues found that all reported AEs were categorized as mild severity. Common AEs included itching, gastrointestinal symptoms, headache, and flushing. These symptoms were either self-limited or easily managed with standard clinical protocols. No patients required emergency care or hospitalization. Anti-natalizumab antibody presence was assessed in 4 cases but was absent and all. No patients discontinued natalizumab infusion treatment.

“In this systematic review of almost 10,000 natalizumab infusions, all infusion-related AEs were mild, and no clinically relevant safety concerns were associated with natalizumab infusions. This highlights a potential opportunity to improve and streamline the infusion and post-infusion monitoring process. Anticipated benefits may include reducing SARS-CoV2 exposure risks for patients and staff, reducing patients’ treatment burden, increasing efficiency, as well as improving access to care without neglecting patient safety,” Wang and colleagues concluded.

For more coverage of ACTRIMS Forum 2021, click here.

REFERENCE

Wang Y, Gallaro D, Mehta D, et al. Evaluation of nearly 10,000 natalizumab infusions at an academic MS center reveals lack of clinically relevant infusion-related safety events. Presented at ACTRIMS Annual Forum; February 25-27, 2021. Abstract P072