Abstract 421P
Background
ICI treatment significantly improved the outcomes of patients (pts) with aNSCLC, thus factors that may hamper ICI effectiveness should be minimised. Antibiotics (atb) disrupt gut microbiota and are associated with shorter overall survival (OS) with ICI treatment. We conducted a retrospective observational study to describe atb prescription patterns in pts with aNSCLC treated with ICIs and evaluate their impact on treatment outcomes.
Methods
Consecutive pts with aNSCLC, treated with ICIs at a single academic center, between Jul 2015 and Dec 2022,were included. Data on atb use were obtained from electronic medical records, and data relevant for oncology care were collected prospectively in a standardized manner. Treatment with atb was assessed in different time frames relative to the start of ICI via the number of atb exposures and prescribed daily defined doses (DDD).
Results
A total of 369 pts were included (male 58%, median age 65 years, performance status 0–1 83%), that received ICI in the first-line (43% monotherapy, 26% chemo-immunotherapy) or second-line treatment (31%). Most patients (70%) were prescribed atb at least once within 1 year prior the start and until the end of ICI treatment, with 30%, 14% and 9% of pts prescribed atb within the time frame of 1 year to 60 days, 60 to 30 days and 30 days prior to ICI, respectively. Pts were most often prescribed penicillins (57%), macrolides (22%) and fluoroquinolones (22%), with a median of 2 atb exposures and a median DDD of 23. Prescription of atb within one year prior to start of ICI was associated with shorter OS in uni- (mOS atb vs. non-atb: 17.0 vs 25.4 months; HR=1.29; 95% CI: 1.00–1.67) but not in multivariate analysis (aHR=1.24; 95% CI: 0.95–1.63). Atb use within other times frames, atb class, number of exposures and DDD were not associated with OS, although trends indicating worse outcomes in atb users were observed.
Conclusions
Antibiotic use is common in pts with aNSCLC, especially within the year prior to ICI treatment. As this may negatively impact survival outcomes, strategies to minimize unnecessary antibiotic use should be explored in future research.
Legal entity responsible for the study
The authors.
Funding
This work was financially supported by the Slovenian Research Agency, Grant No. P1-0189 and P3-0360.
Disclosure
L. Knez: Financial Interests, Personal, Invited Speaker: Roche, MSD; Financial Interests, Institutional, Other, Educational projects within employment at the University of Ljubljana, Faculty of Pharmacy.: Swixx, Krka; Financial Interests, Institutional, Other, Research projects within employment at the University of Ljubljana, Faculty of Pharmacy: AstraZeneca. U. Janzic: Financial Interests, Personal, Invited Speaker: MSD, AstraZeneca, Pfizer, Takeda, Amgen; Financial Interests, Personal, Advisory Board: Roche, BMS, Medison. All other authors have declared no conflicts of interest.