A systematic review and meta-analysis evaluating the impact of antibiotic use on the clinical outcomes of cancer patients treated with immune checkpoint inhibitors.

Background: Immune checkpoint inhibitors (ICIs) have considerably improved patient outcomes in various cancer types, but their efficacy remains poorly predictable among patients. The intestinal microbiome, whose balance and composition can be significantly altered by antibiotic use, has recently emerged as a factor that may modulate ICI efficacy. The objective of this systematic review and meta-analysis is to investigate the impact of antibiotics on the clinical outcomes of cancer patients treated with ICIs. Methods: PubMed and major oncology conference proceedings were systematically searched to identify all studies reporting associations between antibiotic use and at least one of the following endpoints: Overall Survival (OS), Progression-Free Survival (PFS), Objective Response Rate (ORR) and Progressive Disease (PD) Rate. Pooled Hazard Ratios (HRs) for OS and PFS, and pooled Odds Ratios (ORs) for ORR and PD were calculated. Subgroup analyses on survival outcomes were also performed to investigate the potential differential effect of antibiotics according to cancer types and antibiotic exposure time windows. Results: 107 articles reporting data for 123 independent cohorts were included, representing a total of 41,663 patients among whom 11,785 (28%) received antibiotics around ICI initiation. The pooled HRs for OS and PFS were respectively of 1.61 [95% Confidence Interval (CI) 1.48-1.76] and 1.45 [95% CI 1.32-1.60], confirming that antibiotic use was significantly associated with shorter survival. This negative association was observed consistently across all cancer types for OS and depending on the cancer type for PFS. The loss of survival was particularly strong when antibiotics were received shortly before or after ICI initiation. The pooled ORs for ORR and PD were respectively of 0.59 [95% CI 0.47-0.76] and 1.86 [95% CI 1.41-2.46], suggesting that antibiotic use was significantly associated with worse treatment-related outcomes. Conclusion: As it is not ethically feasible to conduct interventional, randomized, controlled trials in which antibiotics would be administered to cancer patients treated with ICIs to demonstrate their deleterious impact versus control, prospective observational studies and interventional trials involving microbiome modifiers are crucially needed to uncover the role of microbiome and improve patient outcomes. Such studies will reduce the existing publication bias by allowing analyses on more homogeneous populations, especially in terms of treatments received, which is not possible at this stage given the current state of the field. In the meantime, antibiotic prescription should be cautiously considered in cancer patients receiving ICIs. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42019145675.

Prognostic Associations of Concomitant Antibiotic Use in Patients with Advanced NSCLC Treated with Atezolizumab: Sensitivity Analysis of a Pooled Investigation of Five Randomised Control Trials.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have been a significant milestone for the treatment of advanced non-small cell lung cancer (NSCLC). However, the efficacy of ICIs can vary substantially between patients, with disparities in treatment outcomes being potentially driving by changes in the microbiome. Antibiotics can cause dysbiosis and are hypothesised to impact the efficacy of ICIs Methods: Data were pooled from five randomised clinical control trials, IMpower130, IMpower131, IMpower150, OAK, and POPLAR, assessing atezolizumab in advanced NSCLC. Cox proportional hazard models were used to determine whether antibiotic use within 6-weeks before and after randomisation was associated with progression-free survival (PFS) and overall survival (OS) outcomes, with data further stratified by programmed death ligand-1 (PD-L1) status. RESULTS: Antibiotic use was significantly associated with worsened PFS (hazard ratio (HR) = 1.19 [1.08-1.30], p ≤ 0.001) and OS (HR = 1.27 [1.13-1.42], p ≤ 0.001) in patients treated with atezolizumab and those not treated with atezolizumab (PFS, HR = 1.21 [1.08-1.36] p < 0.001, OS, HR = 1.33 [1.16-1.51] p < 0.001). These associations were relatively consistent in both PD-L1 positive and PD-L1 negative. CONCLUSIONS: Antibiotic use within a ±6-week window was significantly associated with worse PFS and OS.

Spare and repair the gut microbiota from antibiotic-induced dysbiosis: state-of-the-art.

Homeostasis of the intestinal microbiota is currently recognized as a major contributor to human health. Furthermore, intestinal dysbiosis is associated with a multitude of consequences, including intestinal colonization by antibiotic-resistant or pathogenic bacteria, such as Clostridioides difficile, and reduced efficacy of promising anticancer immunotherapies. By far, the most immediate and drastic exposure leading to dysbiosis is antibiotic treatment. Many attempts have been made to prevent or repair antibiotic-associated dysbiosis. Here, we review these innovations and the difficulties associated with their development.

NSCLC Immunotherapy Efficacy and Antibiotic Use: A Systematic Review and Meta-Analysis.

Immune checkpoint inhibitors (ICIs) have dramatically improved patient outcomes in a variety of tumor types, but with variable efficacy. Recent research has suggested that antibiotic-induced disruption of the microbiota may impact ICI efficacy. We performed a systematic review and meta-analysis of studies that assessed the impact of antibiotic use on the survival of patients diagnosed with NSCLC and treated with ICI. We systematically searched Medline, the Cochrane Library, and major oncology conferences proceedings. Eligible studies mentioned hazard ratio or Kaplan-Meier curves for progression-free survival (PFS) or overall survival (OS) based on antibiotic exposure before or during ICI treatment. We identified 23 eligible studies. The impact of antibiotics was then evaluated in 2208 patients for PFS and 5560 for OS. For both PFS and OS meta-analyses, the between-study heterogeneity was high (Higgins and Thompson I2 of 69% and 80%, respectively). The pooled hazard ratio was 1.47 (95% confidence interval [CI]: 1.13-1.90) for PFS and 1.69 (95% CI: 1.25-2.29) for OS revealing a significantly reduced survival in patients with NSCLC exposed to antibiotics. The median OS was reduced on average by 6.7 months (95% CI: 5.1-8.4) in the patients exposed to antibiotics. The effect seems to depend on the time window of exposure with stronger effects reported when the patients took antibiotics [-60 days; +60 days] around ICI initiation. In patients with NSCLC, the findings of the meta-analysis indicate that antibiotic use before or during treatment with ICI leads to a median OS decreased by more than 6 months. Specifically, exposure shortly before or after ICI initiation seems to be particularly detrimental, whereas antibiotic use later during disease course does not seem to alter survival. Because PFS and OS were difficult to compare between studies owing to heterogeneity and the multiple confounding factors identified, further studies are needed to strengthen the understanding of this phenomenon.