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Causality: well established
Causality assessment · Causality: well established
Rituximab and Progressive multifocal leukoencephalopathy: is the FAERS signal real?
A written Bradford Hill assessment of one drug–event pair. The grade is a judgement about the signal, not a statement that this drug causes this event in any one person; FAERS counts are reports, not rates.
Rituximab ↔ Progressive multifocal leukoencephalopathy
n=1,797 co-reports · PRR 27.6 · ROR 27.8
Rituximab carries a boxed warning for progressive multifocal leukoencephalopathy (PML), an often-fatal JC-virus brain infection arising from prolonged B-cell depletion; 1,797 co-reports give PRR 27.6. The label advises vigilance for neurological symptoms and consideration of stopping therapy.
Regulatory basis: rituximab prescribing information — boxed warning for progressive multifocal leukoencephalopathy.
| Bradford Hill viewpoint | Status | Note |
|---|---|---|
| Temporality (necessary) | met | Months of immunosuppression |
| Strength | met | PRR 27.6 with 1,797 co-reports |
| Consistency | met | Reproduced across cohorts |
| Specificity | met | Fairly specific to B-cell depleters |
| Biological gradient | not established | Not clearly dose-related |
| Plausibility | met | Known JC-virus reactivation mechanism |
| Coherence | met | Fits rituximab immunosuppression |
| Experiment | n/a | Too rare for trial detection |
| Analogy | met | Analogous to natalizumab PML |
This table is this page's own qualitative read of the literature cited above, not an automated or citation-gated assessment — see the note at the bottom of this page.
✗ No ClinicalTrials.gov results-posting trial in the top search hits for rituximab captured progressive multifocal leukoencephalopathy as a tracked adverse event in a usable structure. A rare opportunistic infection is far below the detection threshold of randomised trials.