No association between chronic use of ranitidine, compared with omeprazole or famotidine, and gastrointestinal malignancies

BACKGROUND

In 2019, the United States Food and Drug Administration detected above-regulation levels of the human carcinogen N-nitrosodimethylamine (NDMA) in ranitidine, resulting in a complete removal of the medication from the market. NDMA is known to cause gastrointestinal malignancies in animal models.

AIM

To determine if patients who were receiving ranitidine have a higher risk of developing cancers of the digestive tract compared to patients taking other anti-reflux medications.

METHODS

Using the nationwide database IBM Explorys, patients taking ranitidine were compared to patients on either famotidine or omeprazole. Incidence data of new malignancies of the oesophagus, stomach, liver, pancreas, and colon/rectum were obtained in 1-year intervals for up to 10 years. Two multivariable logistic regression models were used to calculate odds ratios (ORs), one adjusting for common risk factors for each cancer studied, and the other for demographic factors.

RESULTS

Patients on ranitidine who were compared to patients on famotidine had ORs of 0.51(95% CI 0.43-0.60), 0.43(95% CI 0.36-0.51), 0.39(95% CI 0.36-0.41), 0.54(95% CI 0.49-0.62), and 0.46(95% CI 0.43-0.49) of developing oesophageal, gastric, hepatocellular, pancreatic, and colorectal cancers, respectively (P < 0.001). Patients on ranitidine compared to omeprazole had ORs of 0.62(95% CI 0.52-0.72), 0.58(95% CI 0.49-0.68), 0.81 (95% CI 0.76-0.86), 0.68(95% CI 0.60-0.76), and 0.66(95% CI 0.62-0.70) of developing oesophageal, gastric, hepatocellular, pancreatic, and colorectal cancers respectively (P < 0.001).

CONCLUSIONS

Use of ranitidine was not associated with an increased odds of developing gastrointestinal malignancies compared to omeprazole or famotidine use.

Combined epigenetic and metabolic treatments overcome differentiation blockade in acute myeloid leukemia

A hallmark of acute myeloid leukemia (AML) is the inability of self-renewing malignant cells to mature into a non-dividing terminally differentiated state. This differentiation block has been linked to dysregulation of multiple cellular processes, including transcriptional, chromatin, and metabolic regulation. The transcription factor HOXA9 and the histone demethylase LSD1 are examples of such regulators that promote differentiation blockade in AML. To identify metabolic targets that interact with LSD1 inhibition to promote myeloid maturation, we screened a small molecule library to identify druggable substrates. We found that differentiation caused by LSD1 inhibition is enhanced by combined perturbation of purine nucleotide salvage and de novo lipogenesis pathways, and identified multiple lines of evidence to support the specificity of these pathways and suggest a potential basis of how perturbation of these pathways may interact synergistically to promote myeloid differentiation. In sum, these findings suggest potential drug combination strategies in the treatment of AML.

Drug Sensitivity and Allele Specificity of First-Line Osimertinib Resistance EGFR Mutations

Osimertinib, a mutant-specific third-generation EGFR tyrosine kinase inhibitor, is emerging as the preferred first-line therapy for EGFR-mutant lung cancer, yet resistance inevitably develops in patients. We modeled acquired resistance to osimertinib in transgenic mouse models of EGFR^L858R -induced lung adenocarcinoma and found that it is mediated largely through secondary mutations in EGFR-either C797S or L718V/Q. Analysis of circulating free DNA data from patients revealed that L718Q/V mutations almost always occur in the context of an L858R driver mutation. Therapeutic testing in mice revealed that both erlotinib and afatinib caused regression of osimertinib-resistant C797S-containing tumors, whereas only afatinib was effective on L718Q mutant tumors. Combination first-line osimertinib plus erlotinib treatment prevented the emergence of secondary mutations in EGFR. These findings highlight how knowledge of the specific characteristics of resistance mutations is important for determining potential subsequent treatment approaches and suggest strategies to overcome or prevent osimertinib resistance in vivo. SIGNIFICANCE: This study provides insight into the biological and molecular properties of osimertinib resistance EGFR mutations and evaluates therapeutic strategies to overcome resistance. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/10/2017/F1.large.jpg.