Abstract 1874P
Background
Administration of antibiotics has been suggested to have a negative impact on cancer outcome in patients who start immune checkpoints inhibitors (iCPI) therapy due to changes in the gut microbiota.
Methods
Observational, retrospective, unicentric study of a cohort of patients with advanced solid neoplasms who receive iCPi monotherapy outside clinical trial in a tertiary hospital that explores the incidence of infections and the use of antibiotics, and its possible impact on cancer response and survival. Prognostic factor and efficacy analysis were calculated using Kaplan-Meyer, Chi-square and long-rank tests. Univariant analysis included age, sex, ECOG functional status, Charlson comorbidity index, body mass index (BMI), type of neoplasm, line of therapy, administered drug, neutrophil/lymphocyte ratio (NLR), serum albumin level, serum lactic dehydrogenase level and corticoid therapy before the start of iCPI therapy. PD-L1 expression in the tumor was only available in a minority of patients, so it was not included in the analysis.
Results
199 patients with advanced solid neoplasms (135 non-small lung cancers, 30 melanomas, 12 renal cancers, 11 head and neck cancers, 8 urothelial cancers, 1 hepatocellular carcinoma, 1 choriocarcinoma, and 1 Merkel tumor) treated with iCPI monotherapy were included from January 2013 to December 2018. After a median follow-up of 21,8 months, 65 patients (32,7%) suffered at least one infection and 98,5% of them received antibiotic therapy. Aetiologic agent was found in 23 cases: bacteria (78,2%), virus (17,4%) and fungi (4,3%). There were no differences in the rate of tumoral responses (21,7% vs19,7%), progression free survival (3, 0 vs 3,2 months) and overall survival (7,1 vs 6,9 months) between patients with and without infection.
Conclusions
This observational, retrospective study has been unable to demonstrate a negative impact of the incidence of infections that require antibiotic therapy on response rate or survival in patients with advanced solid neoplasms who were under iCPI treatment in our hospital. Prospective studies are needed to answer this question.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.