Topical antimicrobial peptide omiganan recovers cutaneous dysbiosis but does not improve clinical symptoms in patients with mild to moderate atopic dermatitis in a phase 2 randomized controlled trial

J Am Acad Dermatol. 2022 Apr;86(4):854-862. doi: 10.1016/j.jaad.2020.08.132. Epub 2020 Oct 1.


Background: Dysbiosis and colonization with Staphylococcus aureus is considered to play an important role in the pathogenesis of atopic dermatitis (AD). Recovering this dysbiosis may improve AD symptoms. Omiganan is a synthetic indolicidin analogue antimicrobial peptide with activity against S aureus and could be a viable new treatment option for AD.

Objective: To explore the tolerability, clinical efficacy, and pharmacodynamics of omiganan in mild to moderate AD.

Methods: Eighty patients were randomized to omiganan 1%, 1.75%, or 2.5% or vehicle twice daily for 28 days on all lesions. Weekly visits included clinical scores and microbiological and pharmacodynamic assessments of 1 target lesion.

Results: In all omiganan treatment groups, dysbiosis was recovered by reducing Staphylococcus species abundance and increasing diversity. A reduction of cultured S aureus was observed in all omiganan treatment groups, with a significant reduction for omiganan 2.5% compared to vehicle (-93.5%; 95% CI, -99.2 to -28.5%; P = .02). No significant clinical improvement was observed.

Conclusion: Topical administration of omiganan twice daily for up to 28 days in patients with mild to moderate AD led to a recovery of dysbiosis but without clinical improvement. Therefore, a monotreatment that selectively targets the microbiome does not appear to be a successful treatment strategy in mild to moderate AD.

Keywords: Staphylococcus aureus; antimicrobial peptide; atopic dermatitis; dysbiosis; omiganan; pharmacodynamics.

Publication types

  • Clinical Trial, Phase II
  • Randomized Controlled Trial

MeSH terms

  • Antimicrobial Cationic Peptides
  • Antimicrobial Peptides*
  • Dermatitis, Atopic* / diagnosis
  • Dysbiosis / drug therapy
  • Humans
  • Skin / pathology
  • Staphylococcus aureus


  • Antimicrobial Cationic Peptides
  • Antimicrobial Peptides
  • Omiganan