Tralokinumab treatment improves the skin microbiota by increasing the microbial diversity in adults with moderate-to-severe atopic dermatitis: Analysis of microbial diversity in ECZTRA 1, a randomized controlled trial

Background: Atopic dermatitis (AD) is characterized by microbial dysbiosis, immune dysregulation, and an impaired skin barrier. Microbial dysbiosis in AD involves a reduction in diversity primarily driven by an increased abundance of Staphylococcus aureus. Tralokinumab, an approved treatment for adults with moderate-to-severe AD, improves the skin barrier and immune abnormalities by specifically targeting the interleukin 13 cytokine, but its impact on the skin microbiome is unknown. Objective: To investigate how tralokinumab affects the skin microbiome by examining the lesional skin of adults with moderate-to-severe AD from the phase 3 ECZTRA 1 trial (NCT03131648). Methods: Microbiome profiling, S aureus abundance, and biomarker data were assessed in a subset of ECZTRA 1 participants (S aureus abundance at baseline and week 16; microbiome profiling at baseline, and week 8/16; and serum sampling before dose and week 4/8/16/28/52). Results: Tralokinumab treatment led to increased microbial diversity, reduced S aureus abundance, and increased abundance of the commensal coagulase-negative Staphylococci. Limitations: Limitations include a lack of S aureus abundance data at week 8, sampling site variation between participants, and possible influence from concomitant systemic antiinfectives. Conclusion: Our findings indicate specific targeting of the interleukin 13 cytokine with tralokinumab can directly and/or indirectly improve microbial dysbiosis seen in AD skin.