- Natalizumab is effective for induction of clinical remission in some patients with moderately to severely active Crohn's disease (CD), but it is linked to the development of progressive multifocal leukoencephalopathy (PML), a rare, sometimes fatal, neurological adverse event.
Why this matters
- Alternative biologics to natalizumab are advised.
- Qualitative review of 5 randomized controlled trials (RCTs) (n=1771) comparing 1, 2, or 3 infusions of natalizumab (300 mg or 3 mg/kg or 6 mg/kg) to placebo or control therapy.
- 5 RCTs were obtained from search of MEDLINE, EMBASE, CENTRAL, the Cochrane IBD Group Specialized Trials Register, and clinicaltrials.gov.
- Funding: None disclosed.
- Studies of high quality find that natalizumab for moderately to severely active CD has around a 30% likelihood of clinical response, including remission, at 12 weeks after 2-3 infusions.
- Common adverse events included headache, nausea, nasopharyngitis, abdominal pain, fatigue, vomiting, and worsening of CD.
- Natalizumab is linked to PML as a rare, sometimes fatal, neurological adverse event, but its likelihood is unknown because none of the included studies had sufficient power to detect it.
- No tests can predict who is at risk for PML.
- Small number of studies.
- Sample sizes were too small to detect PML as a rare adverse event.