Risk of herpes zoster with IL-17 inhibitor therapy for psoriasis and other inflammatory conditions.

Background: Psoriasis is a chronic inflammatory skin disease that has been associated with a significantly higher risk of herpes zoster (HZ). Several newer biologics such as secukinumab, ixekizumab, and brodalumab inhibit IL-17 and have been highly effective for treatment of psoriasis. However, adverse events related to the immunosuppressive properties of these biologics have been observed. Methods: This review aims to synthesize and evaluate the literature investigating the risk of HZ in patients treated with IL-17 inhibitors, with a focus on psoriasis patients. We performed searches using the PubMED database with the following search terms: 'psoriasis,' 'herpes zoster,' 'secukinumab,' 'ixekizumab,' 'brodalumab,' 'IL-17,' 'anti-IL-17,' and 'safety.' Clinical trials, cohort studies, review articles, and meta-analyses were evaluated. Results: Studies did not detect a higher risk of HZ infections in psoriasis patients treated with IL-17 inhibitors when compared to those treated with placebo or other therapies. Studies of IL-17 inhibitors for other indications including psoriatic arthritis, rheumatoid arthritis, ankylosing spondylitis, and asthma yielded similar results. Conclusion: IL-17 inhibitors do not appear to increase risk of HZ. However, IL-17 inhibitors are relatively new medications, and further long-term data may be necessary to confirm this finding. Nevertheless, HZ vaccination should be considered on a case-bycase basis prior to initiating IL-17 therapy.