Prognostic Impact of the Administration of Antibiotics and Proton Pump Inhibitors in Immune Checkpoint Inhibitor Combination Therapy for Advanced Renal Cell Carcinoma.

Background/aim: The prognostic impact of the administration of antibiotics and proton pump inhibitors (PPIs) in immune checkpoint inhibitor (ICI) therapy for advanced cancer has recently been documented. However, how these drugs affect the outcomes of first-line ICI combination therapy for advanced renal cell carcinoma (RCC) remains unclear.

Patients and methods: We retrospectively evaluated the data of 128 patients with RCC who received first-line ICI combination therapy. The patients were grouped according to their history of antibiotics and PPIs use one month before the initiation of ICI combination therapy. Progression-free survival (PFS), overall survival (OS), and objective response rate (ORR) after ICI combination therapy were compared between patients treated with and without antibiotics or PPIs.

Results: Of the 128 patients, 30 (23%) and 44 (34%) received antibiotics and PPIs, respectively. Patients treated with antibiotics exhibited shorter PFS and OS compared to those who did not receive antibiotics (median PFS: 4.9 vs. 16.1 months, p<0.0001; OS: 20.8 vs. 49.0 months, p=0.0034). Multivariate analyses showed that antibiotic administration was an independent predictor of shorter PFS (hazard ratio: 2.54: p=0.0002) and OS (hazard ratio: 2.56: p=0.0067) after adjusting for other covariates. In contrast, there were no significant differences in either PFS or OS between patients who received PPIs and those who did not. (PFS: p=0.828; OS: p=0.105).

Conclusion: Antibiotics administration before ICI combination therapy was negatively associated with outcomes of first-line ICI combination therapy for advanced RCC. Therefore, careful monitoring is required for potentially high-risk patients undergoing ICI combination therapy.