Herpes zoster in patients receiving JAK inhibitors for ulcerative colitis: Mechanism, epidemiology, management, and prevention

Increased risk of herpes zoster (HZ) has been observed in patients with immune-mediated diseases, including rheumatoid arthritis (RA), psoriasis (PsO), and inflammatory bowel disease; this risk can be further increased by the use of immunosuppressive therapy. One advancing modality of therapy for these diseases is Janus kinase (JAK) inhibition. Tofacitinib is an oral JAK inhibitor for the treatment of RA and psoriatic arthritis, which is currently under investigation for the treatment of ulcerative colitis (UC) and was previously investigated for psoriasis. JAK inhibitors have been associated with HZ events in patients across a number of indications. The pathogenesis underlying this risk of HZ is currently unknown. An increased risk of HZ has been noted in patients receiving immunosuppressive therapies for UC, including tofacitinib. In clinical trials, there was a dose-dependent risk of HZ (higher dose linked with increased risk). However, the majority of HZ cases are nonserious and noncomplicated, mild to moderate in severity, and manageable without permanent discontinuation of treatment. This review will discuss HZ risk in patients receiving JAK inhibitors, focusing on tofacitinib with respect to the potential mechanisms and epidemiology of HZ. Current guidelines for the prevention of HZ will be highlighted, and proposed management reviewed.