Relapsing MS: hookworm treatment misses the mark in WIRMS trial

  • Tanasescu R & al.
  • JAMA Neurol
  • 15 Jun 2020

  • curated by Susan London
  • Clinical Essentials
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  • Among patients with relapsing multiple sclerosis (MS), hookworm treatment was safe but did not affect lesion findings on MRI.

Why this matters

  • Approaches that modify the innate immune response are attractive.
  • Editorial: Despite safety, efficacy "appears modest, making it unlikely to be a sufficient stand-alone treatment for MS."
    • Also notes concerns about helminths as add-on, "given the potential increase in infection rates when used with concomitant immunomodulating medications.”

Key results

  • During months 3 to 9 postinfection, no significant difference was detected between hookworm and placebo groups in total number of new T2 lesions, newly enhancing T1-weighted lesions, or T2 enlarging lesions:
    • Median: 0 vs 1.5.
    • Mean: 4.1 vs 3.8.
  • Hookworm group:
    • Somewhat less likely to have any MRI activity (OR, 0.33; 95% CI, 0.11-1.02).
    • Higher percentage of CD4+CD25highCD127neg T cells in peripheral blood (4.4% vs 3.9%; P=.01).
    • Lower relapse rate per patient (14.3% vs 30.6%).
  • No withdrawals for adverse effects.
  • Only differing adverse event was more application-site skin discomfort in hookworm group (82.86% vs 27.78%).

Study design

  • UK single-center phase 2 randomized controlled trial among 71 adults with relapsing MS not receiving disease-modifying treatment (WIRMS trial).
  • Randomization: single transcutaneous administration of live, infective hookworms (25 Necator americanus larvae) vs placebo.
  • Main outcome: new/enlarging/enhancing MRI lesions.
  • Funding: MS Society of Great Britain and Northern Ireland; Bayer-Schering; others.


  • Choice of main outcome measure.
  • Fairly short treatment duration.
  • Unclear generalizability to progressive MS.