Systematic review of newer agents for the management of alopecia areata in adults: Janus kinase inhibitors, biologics and phosphodiesterase-4 inhibitors.

Management options for moderate-to-severe alopecia areata (AA) are limited owing to a lack of safe and effective treatments suitable for long-term use. However, newer agents have the potential to induce and maintain hair regrowth in patients with a better side-effects profile compared to systemic steroids or conventional systemic agents. In this article, we conducted a systematic review of newer agents, including Janus kinase (JAK) inhibitors, biologics and phosphodiesterase-4 (PDE-4) inhibitors, for the treatment of AA in adult patients evaluated in randomized controlled trials (RCTs) using the Severity of Alopecia Tool score. A literature search was performed on PubMed and ClinicalTrials.gov, which identified 106 items with 12 RCTs eligible for review. Information regarding the treatment regimen, duration, endpoints, efficacy and adverse events were extracted; product monograph information was also summarized for approved agents with or without indications for AA. Overall, current data suggest the oral JAK inhibitors (baricitinib, ritlecitinib, deuruxolitinib, brepocitinib) as a promising new class of agents that can induce significant hair regrowth, with mild to moderate adverse effects. Baricitinib recently received US FDA approval for the treatment of severe AA, while ritlecitinib and deuruxolitinib have received the breakthrough therapy designation for AA. In contrast, PDE-4 inhibitors (apremilast) and the biologics (dupilumab, secukinumab and aldesleukin) appear to have limited efficacy thus far. Results from ongoing and future long-term studies could shed light on the utility of the newer agents in altering the progression of AA.