Progressive multifocal leukoencephalopathy associated with immunosuppressive therapy in rheumatic diseases: Evolving role of biologic therapies

PML has been reported in patients with ARD treated with various immunosuppressive agents. The limitations of this study preclude definitive attribution of causality. While the paucity of confirmed cases recently exposed to anti-TNF therapy suggests a causal relationship is unlikely, a specific signal is emerging with regard to rituximab and PML. Although this is a rare adverse event associated with RTX therapy, the devastating nature of PML mandates continued vigilance, particularly in patients with current or prior exposure to an alkylating agent.