“Our results confirm the detrimental impact on oncological outcomes of antibiotics and glucocorticoids at a dosage ≥10 mg/day when given within 1 month before or after ICI onset,” Marie Kostine, MD, of Bordeaux (France) University Hospital, and colleagues wrote in the European Journal of Cancer. “Moreover, we show that other comedications may significantly alter the antitumoral response of ICI, such as proton pump inhibitors, psychotropic drugs, morphine, aspirin, and insulin, whereas others seem to have no impact.”
While immune checkpoint inhibitors are transforming the treatment of advanced cancers, gut microbiota composition is an important determinant of response to ICIs. Antibiotic treatments are known to alter the gut microbiota. Other drugs, such as proton pump inhibitors, antidiabetic agents, aspirin, NSAIDs, glucocorticoids, immunomodulators, psychotropic drugs, and analgesics, have been associated with changes in microbiome composition. Since many patients with advanced cancer are exposed to such drugs, this study looked at the possible influence of these comedications on the antitumor effect and safety of ICIs.
The observational study included 635 patients with advanced cancer treated with ICIs between May 2015 and September 2017. Comedications given within 1 month before or 1 month after the first administration of an ICI were reviewed from medical records. Psychotropic drugs, proton pump inhibitors, ACE inhibitors and/or angiotensin II receptor blockers (ARBs), glucocorticoids, antibiotics, statins, and morphine were the most prescribed comedications.
Baseline use of antibiotics, glucocorticoids greater than 10 mg/day, proton pump inhibitors, psychotropic drugs, morphine, and insulin was associated with decreased overall survival and tumor response. However, the coadministration of statins, ACE inhibitors and/or ARBs, NSAIDs, aspirin, and oral diabetes drugs did not impact patient outcomes. Additionally, treatments that altered the response to ICIs were associated with a decreased incidence of immune-related adverse events.
“These results suggest some practical advice in a patient candidate to ICIs,” the authors wrote. “First, antibiotic treatment should be limited to documented infections,” and “withdrawal of proton pump inhibitors and psychotropic drugs should be considered.
“Regarding baseline glucocorticoids use, the cutoff of 10 mg/day should be respected, considering the deleterious effect of higher dosage. Moreover, because of the lack of impact of inhaled or topical glucocorticoids, local routes should be preferred,” the authors wrote. “Conversely, our study brings reassuring data regarding the use of glucocorticoids for the management of immune-related adverse events, which did not alter ICI efficacy, confirming previous reports.”
The authors noted that the observational nature of the study does not allow any causal conclusion, adding that it remains unknown whether the effect of comedications “on cancer outcomes is thoroughly mediated by changes in microbiota or other immunomodulatory properties.”
Along with the retrospective design, study limitations included reporting bias and missing data on baseline comedications, specific prognostic factors and cancer outcomes.
The authors noted no conflicts of interest.