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Risk of progressive multifocal leukoencepholopathy in John Cunningham virus antibody-positive patients exposed to natalizumab.
| Exposure (months) | No prior IS use | Prior IS use |
|---|---|---|
| 1–24 | 0.5/1000 | 1.5/1000 |
| 25+ | 3.9/1000 | 10.6/1000 |
IS: Immune suppressant.
Data taken from [151].
