TOPLINE:
In a retrospective cohort study, patients who used antibiotics during immune checkpoint blockade (ICB) therapy had an increased risk for immune-related cutaneous adverse events — particularly if they used broad-spectrum drugs.
METHODOLOGY:ICB therapy improves survival but commonly causes immune‑related skin toxicities — possibly due to perturbation of the skin microbiome. This study examined whether antibiotic exposure during immunotherapy increases the risk of developing those cutaneous adverse events.Researchers conducted a retrospective cohort study of 9912 patients with solid tumors who underwent ICB therapy (initiated at a median age of 65 years) at Memorial Sloan Kettering Cancer Center, New York City, from March 2016 to March 2021.Antibiotic exposure during immunotherapy was treated as a time‑varying covariate, covering the 2 months following each antibiotic prescription. The primary outcome was an oncodermatologist-confirmed immune-related cutaneous adverse event.Cox proportional hazards regression models were used to estimate cause-specific hazard ratios for cutaneous events from ICB initiation, adjusting for age, sex, race, ethnicity, and cancer type.TAKEAWAY:Overall, 714 patients (7.2%) developed an immune-related cutaneous adverse event during their first immunotherapy regimen, with pruritus (51.1%) and maculopapular rash (31.0%) being the most common manifestations.Exposure to antibiotics during immunotherapy was linked to an increased risk for cutaneous side effects (hazard ratio [HR], 1.62; P < .001). Overall, antibiotics with a lower potential for microbiome perturbation were associated with a greater risk (HR, 2.89) than those with medium or high potential (HR, 1.48).When it came to antibiotic spectrum, broad-spectrum agents were associated with an increased risk for immune-related skin events (HR, 1.91), whereas narrow-spectrum agents were not (HR, 0.68).IN PRACTICE:
While causality cannot be established, the authors wrote, these findings “support judicious use” of antibiotics while patients are receiving immunotherapy. The results also “highlight the need for prospective studies to clarify the role of the skin microbiome in immune-related cutaneous adverse event pathogenesis,” they concluded.
SOURCE:
This study, led by Lukas Kraehenbuehl, MD, Kantonsspital Aarau, Aarau, Switzerland, was published online in JAMA Dermatology.
LIMITATIONS:
There was potential underreporting of cutaneous adverse events and possible residual confounding, particularly regarding preexisting conditions and concurrent medications that were not uniformly assessed or documented.
DISCLOSURES:
This study received support from the Swiss National Science Foundation; National Heart, Lung, and Blood Institute; National Cancer Institute; Swim Across America; and Ludwig Institute for Cancer Research. Kraehenbuehl disclosed receiving a grant from the Swiss National Science Foundation during the conduct of the study and personal fees from Sanofi Regeneron, Leo, and AstraZeneca outside the submitted work. Full disclosures are noted in the original article.
This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.