Effects of systemic therapies on pruritus in adults with atopic dermatitis: a systematic review and meta-analysis

Pruritus is a hallmark of atopic dermatitis (AD), which affects disease severity and patient quality of life. In AD uncontrolled with first-line topical therapies or in moderate to severe AD, systemic therapies are used; however, there is a paucity of head-to-head trials comparing the effectiveness of these therapies. The aim of this study was to compare the effectiveness of systemic therapies in relieving pruritus in moderate to severe AD in adults, using a meta-analysis. The PubMed, EMBASE, Medline and CINAHL databases were searched from inception up to 31 May 2020 for randomized, placebo-controlled trials investigating the effectiveness of systemic therapies on pruritus with moderate to severe AD in patients aged ≥ 16 years. In total, 26 studies (n = 5190 participants) were identified. Compared with placebo, there was a large and statistically significant (P < 0.001 for all) reduction in pruritus [standard mean difference (SMD); 95% CI] with dupilumab every 2 weeks (-0.88; -1.13 to -0.63), dupilumab every 2 weeks plus topical corticosteroids (-0.77; -0.91 to -0.62), dupilumab once weekly (-0.99; -1.29 to -0.68), dupilumab once weekly plus topical corticosteroids (-0.70; -0.81 to -0.59). There was also a large and statistically significant reduction with ciclosporin (-1.30; -2.34 to -0.26; P = 0.01) and a large, although not statistically significant reduction with azathioprine (-0.85; -2.07 to 0.35). There was a small reduction with both mepolizumab (-0.27; -0.89 to 0.35) and interferon-γ (-0.31; -0.75 to 0.12). Of the investigational drugs, nemolizumab 2.0 mg/kg was the most effective (-8.13; -9.31 to -6.94). The majority of systemic therapies were superior to placebo in reducing pruritus. In particular, the dupilumab studies consistently showed large improvements in pruritus, while nemolizumab showed the strongest antipruritic effects. However, future head-to-head trials are required for conclusive evidence.