Drug Interactions between amoxicillin / omeprazole / rifabutin and retifanlimab

MONITOR: Use of systemic antibiotics during or close to therapy with immune checkpoint inhibitors (ICIs) such as anti-cytotoxic T-lymphocyte-associated protein (CTLA)-4 monoclonal antibodies and/or inhibitors of programmed cell death-1 (PD-1)/programmed death ligand-1 (PD-L1) may result in reduced clinical efficacy of the ICI. The exact mechanism of this interaction has not been fully characterized, but may be related to alterations in the gut microbiota by the systemic antibiotic, potentially resulting in immune dysregulation and a decreased response to the ICI. A meta-analysis of 6 studies involving nivolumab for the treatment of advanced or metastatic non-small cell lung cancer (NSCLC) found that the median progression-free survival (PFS) and overall survival (OS) were reduced by 1.6 months and 8.8 months, respectively, in patients who were exposed to systemic antibiotics before, during, or after nivolumab therapy. Similarly, a single-site retrospective review of patients (n=291) with advanced cancer (melanoma, NSCLC, or renal cell carcinoma) treated with ICI(s) also revealed poorer clinical outcomes associated with the receipt of systemic antibiotics. This study divided patients into 3 groups: no antibiotics, single course of antibiotics, or cumulative courses of antibiotics (i.e., administration of concurrent or successive antibiotics for >7 days) during the 2 weeks prior to and 6 weeks after ICI treatment. The median PFS (6.3 months vs. 3.7 months vs. 2.8 months, respectively) and median OS (21.7 months vs. 17.7 months vs. 6.3 months, respectively) decreased as the antibiotic use increased, though the difference between no antibiotic use and cumulative courses of antibiotics was the only difference determined to be clinically significant. Additionally, a different retrospective analysis of patients (n=635) with advanced cancer treated with ICIs found that antibiotic use was associated with significantly shorter median OS (8 months vs. 23 months), median PFS (4 months vs. 7 months), as well as a reduction in tumor response (57% vs. 71%) when compared to patients who did not receive antibiotics. In contrast, a retrospective study of patients (n=302) with stage IV NSCLC treated with first-line chemo-immunotherapy combinations (i.e., ICI and cytotoxic chemotherapy) had similar OS, PFS, and objective response rate between those who did and did not receive antibiotics during the 30 days prior to initiating an ICI. The receipt of concurrent systemic antibiotics in this patient population was likewise not associated with changes in OS nor PFS.

MANAGEMENT: Until more information is available, caution and clinical monitoring for reduced efficacy of immune checkpoint inhibitors (ICIs) are advised if systemic antibiotics are indicated prior to, concurrently with, or after an ICI. Antibiotic use should be limited to clinically appropriate indications and durations. Clinicians should consult relevant literature, local and national treatment guidelines, and package labeling for further guidance.

MONITOR: Use of proton pump inhibitors (PPIs) or potassium-competitive acid blockers (P-CABs) concurrently with or in close proximity to immune checkpoint inhibitors (ICIs) such as anti-cytotoxic T-lymphocyte-associated protein (CTLA)-4 monoclonal antibodies and/or inhibitors of programmed cell death-1 (PD-1)/programmed death ligand-1 (PD-L1) may result in reduced clinical efficacy of the ICI. The exact mechanism of this interaction has not been fully characterized, but may be related to alterations in the gut microbiota by the PPI/P-CAB, potentially resulting in immune dysregulation and a decreased response to the ICI. Evidence of this interaction is limited and conflicting. One retrospective analysis of patients with advanced cancer treated with ICIs found that PPI use (n=239/635) was associated with shorter median overall survival (9 months vs. 26.5 months), shorter median progression-free survival (3.5 months vs. 8 months), as well as less frequent tumor response (61% vs. 72%). A retrospective analysis of pooled data from clinical trials of atezolizumab in patients with advanced urothelial carcinoma, identified PPI use during the 30 days before and 30 days after atezolizumab as a negative prognostic marker associated with reductions in overall survival and progression-free survival, which was not observed in the outcomes of patients receiving chemotherapy (docetaxel, paclitaxel, or vinflunine). This association has also been noted in the literature for PPI use during atezolizumab treatment for non-small cell lung cancer. In a separate retrospective study of Japanese patients (n=133) using pembrolizumab (200 mg every 3 weeks or 400 mg every 6 weeks) as second-line therapy or beyond for metastatic urothelial carcinoma, patients using P-CABs were grouped together and analyzed with those using PPIs. Similar to other studies, when grouped together, patients on a PPI or P-CAB within 30 days before or after treatment with pembrolizumab had shorter PFS and OS than those who were not on a PPI or P-CAB. However, when PPI users and P-CAB users were examined as separate groups, multivariate analysis revealed that only PPI use was significantly associated with disease progression. In contrast, a retrospective cohort study of advanced cancer adult patients (n=233) who received nivolumab or pembrolizumab, treatment with a PPI 30 days before or after the ICI revealed no significant effect on overall survival or progression free survival. Data are not available for every ICI.

MANAGEMENT: Until more information is available, caution and clinical monitoring for reduced efficacy of immune checkpoint inhibitors (ICIs) are advised if therapy with a proton pump inhibitor (PPI) or potassium-competitive acid blocker (P-CAB) is required, particularly during the 30 days before or after the ICI is initiated. PPI or P-CAB use should be limited to clinically appropriate indications and durations. Clinicians should consult relevant literature, local and national treatment guidelines, and package labeling for further guidance.

MONITOR: Use of systemic antibiotics during or close to therapy with immune checkpoint inhibitors (ICIs) such as anti-cytotoxic T-lymphocyte-associated protein (CTLA)-4 monoclonal antibodies and/or inhibitors of programmed cell death-1 (PD-1)/programmed death ligand-1 (PD-L1) may result in reduced clinical efficacy of the ICI. The exact mechanism of this interaction has not been fully characterized, but may be related to alterations in the gut microbiota by the systemic antibiotic, potentially resulting in immune dysregulation and a decreased response to the ICI. A meta-analysis of 6 studies involving nivolumab for the treatment of advanced or metastatic non-small cell lung cancer (NSCLC) found that the median progression-free survival (PFS) and overall survival (OS) were reduced by 1.6 months and 8.8 months, respectively, in patients who were exposed to systemic antibiotics before, during, or after nivolumab therapy. Similarly, a single-site retrospective review of patients (n=291) with advanced cancer (melanoma, NSCLC, or renal cell carcinoma) treated with ICI(s) also revealed poorer clinical outcomes associated with the receipt of systemic antibiotics. This study divided patients into 3 groups: no antibiotics, single course of antibiotics, or cumulative courses of antibiotics (i.e., administration of concurrent or successive antibiotics for >7 days) during the 2 weeks prior to and 6 weeks after ICI treatment. The median PFS (6.3 months vs. 3.7 months vs. 2.8 months, respectively) and median OS (21.7 months vs. 17.7 months vs. 6.3 months, respectively) decreased as the antibiotic use increased, though the difference between no antibiotic use and cumulative courses of antibiotics was the only difference determined to be clinically significant. Additionally, a different retrospective analysis of patients (n=635) with advanced cancer treated with ICIs found that antibiotic use was associated with significantly shorter median OS (8 months vs. 23 months), median PFS (4 months vs. 7 months), as well as a reduction in tumor response (57% vs. 71%) when compared to patients who did not receive antibiotics. In contrast, a retrospective study of patients (n=302) with stage IV NSCLC treated with first-line chemo-immunotherapy combinations (i.e., ICI and cytotoxic chemotherapy) had similar OS, PFS, and objective response rate between those who did and did not receive antibiotics during the 30 days prior to initiating an ICI. The receipt of concurrent systemic antibiotics in this patient population was likewise not associated with changes in OS nor PFS.

MANAGEMENT: Until more information is available, caution and clinical monitoring for reduced efficacy of immune checkpoint inhibitors (ICIs) are advised if systemic antibiotics are indicated prior to, concurrently with, or after an ICI. Antibiotic use should be limited to clinically appropriate indications and durations. Clinicians should consult relevant literature, local and national treatment guidelines, and package labeling for further guidance.