Association between Proton Pump Inhibitors and severe hematological toxicity in patients receiving pemetrexed-based anticancer treatment: The prospective IPPEM study

Predictive factors associated with pemetrexed acute toxicity

PURPOSE

Pemetrexed has shown efficacy as monotherapy or in combination with platinum salts in the treatment of non-small cell lung cancer and mesothelioma. However, severe hematological toxicities induced by pemetrexed-based chemotherapy have been observed. Some studies have suggested that drug interactions may be associated with pemetrexed toxicity. The objective of this study was to determine predictive factors, including drug interactions, associated with pemetrexed toxicity.

METHODS

This retrospective open monocentric study included patients consecutively treated with pemetrexed after a multidisciplinary risk assessment. Patients who experienced toxicity of grade 3 or 4 according to the Common Terminology Criteria for Adverse Events v5.0, or a grade 2 leading to a change in management, during the first four courses of pemetrexed, were assigned to the early limiting toxicities (ELT) group. Univariate and multivariable logistic regression models were used to test the association variables with the occurrence of ELT.

RESULTS

Seventy-four patients were included in this study (median age: 67 years, with non-small cell lung cancer adenocarcinoma (88%), mesothelioma (7%), or others (5%). Thirty-six patients (49%) were assigned to the ELT group (27 grades 3 and 4; 9 grade 2 with management modification). Three baseline factors were associated with pemetrexed ELT in univariate and multivariate analysis: cystatin clearance (p = 0.0135), albumin level (p = 0.0333), and proton pump inhibitors use (p = 0.035).

CONCLUSION

To conclude, ELT induced by pemetrexed-based treatments occur frequently in cancer patients in a real-world setting. A pretherapeutic assessment before pemetrexed initiation should include three major checkpoints: use of proton pump inhibitors, sarcopenia, and denutrition evaluation.

Drug-drug interactions with proton pump inhibitors in cancer patients: an underrecognized cause of treatment failure

New concepts and drugs have revolutionized medical treatment for cancers. These drugs, which are very expensive and usually well tolerated, have dramatically improved cancer prognosis. We must use them wisely for patients to fully benefit. Gastric acid antisecretory drugs and particularly proton pump inhibitors (PPIs) revolutionized the treatment of gastroduodenal ulcers and severe gastroesophageal reflux, but are frequently overused for symptomatic treatment of epigastric pain or heartburn. Long-term acid suppression may alter the efficacy of many anticancer drugs, such as tyrosine kinase inhibitors (TKIs), cyclin-dependent kinase (CDK) 4/6 inhibitors and immune checkpoint inhibitors (ICIs), by either decreasing gastric acid secretion and thus drug absorption, or by modifying the gut microbiome that modulates the response to ICIs. Oncologists thus need to pay particular attention to the concomitant use of PPIs and anticancer drugs. These interactions translate into major clinical impacts, with demonstrated loss of efficacy for some TKIs (erlotinib, gefitinib, pazopanib), and conflicting results with many other oral drugs, including capecitabine and CDK 4/6 inhibitors. Furthermore, the profound changes in the gut microbiome due to using PPIs have shown that the benefit of using ICIs may be suppressed in patients treated with PPIs. As the use of PPIs is not essential, we must apply the precautionary principle. The first sentence of a recent Comment in Nature was "Every day, millions of people are taking medications that will not help them". We fear that every day millions of cancer patients are taking medications that harm them. While this may well be only association and not causation, there is enough to make us pause until we reach a clear answer. All these data should encourage medical oncologists to refrain from prescribing PPIs, explaining to patients the risks of interaction in order to prevent inappropriate prescription by another physician.

Effect of Concomitant Proton Pump Inhibitors with Pazopanib on Cancer Patients: A Retrospective Analysis

The absorption of pazopanib depends on gastric pH. PPIs are frequently prescribed for cancer patients to modify gastric acidity, decreasing pazopanib absorption. The aim of our study was, retrospectively, to investigate the impact of PPIs on the clinical efficacy and safety of pazopanib in a cohort of patients treated in our health center. Of the 147 patients who were included retrospectively, 79 (54%) did not take PPIs concomitantly with pazopanib (cohort 1), while 68 (46%) patients did take PPIs concomitantly with pazopanib (cohort 2). The efficacy parameters were lower in patients taking pazopanib and PPIs: the i/tumor response was statistically different between the two cohorts (p = 0.008), in particular, with 19% vs. 3% of the objective response and 24% vs. 43% of progression in cohorts 1 and 2, respectively; ii/median overall survival was 17.6 (95% CI: 12.5−32.8) months in cohort 1 and 8.6 months (95% CI: 5.9−18.6) in cohort 2 (HR = 1.7 [95% CI: 1.2−2.5]; p < 0.006); on multivariable analysis, overall survival was associated with performance status, PPI intake, tumor location, hemoglobin, and PMN/lymphocyte ratio. In contrast, the dose reduction for toxicity and severe adverse events were (non-significantly) less frequent in cohort 1. To conclude, our study shows that combining PPIs with pazopanib has an adverse effect on overall survival. The clinical modifications that were observed are in line with a decrease in pazopanib absorption due to PPIs. This co-medication should be avoided.