ZPL-389

H₄ receptor antagonists are potential novel treatments for inflammatory skin diseases, including atopic dermatitis (AD).

We sought to study the efficacy and safety of ZPL-3893787 (a selective H₄ receptor antagonist) in patients with moderate-to-severe AD.

A randomized, double-blind, placebo-controlled, parallel-group study was conducted to evaluate ZPL-3893787 (30 mg) once-daily oral therapy in adults with moderate-to-severe AD. Patients were randomized (2:1) to ZPL-3893787 (n = 65) or placebo (n = 33) for 8 weeks. Patients had a history of AD for more than 12 months, Eczema Area and Severity Index (EASI) scores of 12 or greater and 48 or less, Investigator's Global Assessment (IGA) scores of 3 or greater, pruritus scores of 5 or greater (0- to 10-point scale), and AD on 10% or greater of body surface area. Efficacy parameters included EASI, IGA, SCORAD, and pruritus assessment.

Treatment with oral ZPL-3893787 showed a 50% reduction in EASI score compared with 27% for placebo. The placebo-adjusted reduction in EASI score at week 8 was 5.1 (1-sided P = .01). Clear or almost-clear IGA scores were 18.5% with ZPL-3893787 versus 9.1% with placebo. SCORAD scores exhibited 41% reduction with ZPL-3893787 versus 26% with placebo (placebo-adjusted reduction of 10.0, P = .004). There was a 3-point reduction (scale, 1-10) in pruritus with ZPL-3893787, but there was a similar reduction with placebo, resulting in a nonsignificant difference (P = .249). Patient-reported pruritus subscores obtained from SCORAD were reduced with ZPL-3893787 compared with placebo at week 8 (nonsignificant). ZPL-3893787 was well tolerated.

For the first time, these results showed that ZPL-3893787 improved inflammatory skin lesions in patients with AD, confirming H₄ receptor antagonism as a novel therapeutic option.

A wide array of miscellaneous agents is being studied for the treatment of atopic dermatitis (AD), including targeted topical, oral systemic, and biologic agents.

To review the known efficacy and safety to date for such agents being studied for the treatment of AD.

A nonsystematic review of the literature was performed. PubMed and ClinicalTrials.gov were searched for studies assessing agents not described previously for the treatment of AD. Randomized controlled trials were primarily sought, but other study types were also included if they contained pertinent data. Agents are presented by mechanism of action, with analysis of mechanism of action and data regarding efficacy and safety in patients with AD.

Data regarding the following agents are presented: omiganan (an antimicrobial peptide), tapinarof (a nonsteroidal anti-inflammatory agent), PR022 (hypochlorous acid), asimadoline (a κ-opioid agonist), DS107 (dihomo-γ-linolenic acid), ZPL-389 (a histamine H4 receptor antagonist), secukinumab (an interleukin 17A inhibitor), and fezakinumab (interleukin 22 inhibitor).

Limited clinical data exist for many of the described agents.

As recent research has improved our understanding of AD pathogenesis, various agents with unique mechanisms of action have been studied for the treatment of AD. Many of these hold great therapeutic promise for AD, and continued research and development is warranted.