Abstract
Treatments for alopecia areata (AA) have traditionally been prescribed off-label, and there has been no universal agreement on how to best manage the condition. Baricitinib is the first oral selective Janus kinase (JAK) inhibitor approved for the treatment of adults with severe AA. As a better understanding of the evidence supporting the management of AA in clinical practice is needed, we conducted a systematic literature review and subsequent narrative review to describe available evidence pertaining to the efficacy and tolerability of treatments currently recommended for adults with moderate-to-severe forms of AA. From 2557 identified records, a total of 53 records were retained for data extraction: 9 reported data from 7 randomized controlled trials (RCTs) versus placebo, and 44 reported data from unique RCTs with no placebo arm, non-randomized trials, or observational studies. Across drug classes, data were reported heterogeneously, with little consistency of data collection or clinical endpoints used. The most robust evidence was for the JAK inhibitor class, in particular the JAK1/JAK2 inhibitor baricitinib. Five RCTs (three for baricitinib) demonstrated a consistent benefit of JAK inhibitor therapy over placebo across various clinical outcomes in adult patients with at least 50% scalp hair loss. Overall, hair regrowth varied widely for the other drug classes and was generally low for patients with moderate-to-severe AA. Relapses were commonly observed during treatment and upon discontinuation. Adverse effects were generally consistent with the known safety profile of each intervention. The heterogeneity observed prevented the conduct of a network meta-analysis or an indirect comparison of different treatments. We found that the current management of patients with moderate-to-severe AA often relies on the use of treatments that have not been well evaluated in clinical trials. The most robust evidence identified supported the use of baricitinib, and other oral JAK inhibitors, in patients with severe AA.