Clinical implications of natalizumab Fab-arm exchange in patients with multiple sclerosis - Takeaways - MDSpire

Clinical implications of natalizumab Fab-arm exchange in patients with multiple sclerosis

  • By

  • Liza M.Y. Gelissen

  • Stefan P.H. van den Berg

  • Alyssa A. Toorop

  • Martijn T. Wijburg

  • Emma C. Tallantyre

  • Ninotska I.L. Derksen

  • Floris C. Loeff

  • Joep Killestein

  • Theo Rispens

  • Zoé L.E. van Kempen

  • the NEXT-MS study group

  • May 8, 2026

  • 0 min

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  • 1

    Natalizumab can undergo Fab-arm exchange with endogenous IgG4, resulting in monovalent and bivalent variants with differing efficacy.

  • 2

    Bivalent natalizumab levels were lower in patients with progressive multifocal leukoencephalopathy, contrary to expectations regarding PML risk.

  • 3

    Extended interval dosing of natalizumab significantly reduced bivalent levels compared to standard dosing, with over half falling below quantification thresholds.

  • 4

    Patients experiencing wearing-off symptoms during natalizumab therapy had lower bivalent levels, indicating a potential link that requires further study.

  • 5

    The clinical significance of natalizumab's Fab-arm exchange remains unclear, necessitating further investigation into its effects on treatment outcomes.

Original Source(s)

Clinical implications of natalizumab Fab-arm exchange in patients with multiple sclerosis

  • by Liza M.Y. Gelissen, Stefan P.H. van den Berg, Alyssa A. Toorop, Martijn T. Wijburg, Emma C. Tallantyre, Ninotska I.L. Derksen, Floris C. Loeff, Joep Killestein, Theo Rispens, Zoé L.E. van Kempen, the NEXT-MS study group

  • May 8, 2026

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