1857P - Tyrosine kinase inhibitors and acid-inhibitory drugs: Strong concomitant dispensing and drug-drug interaction risk

Abstract

Background: Tyrosine Kinase Inhibitors (TKIs) have rapidly become an established therapy in oncology and have been shown to be effective in a wide variety of solid and hematologic malignancies. Acid-inhibitory drugs (AID) (such as antacids, anti-ulcerous drugs and proton pump inhibitors - PPIs) increase the intragastric pH, which may subsequently decrease TKI solubility, bioavailability, and treatment efficacy. The Observatory of Drugs Bretagne/ Pays de la Loire (B-PL) and the Medical Department of the French Regional Health Insurance (FRHI PL) has made an observational study about TKIs and AIDs concomitant dispensing. Methods: FRHI has made an extract in its database for patients treated with TKIs and AIDs in 2016. Concomitant dispensing is defined as the dispensing of a TKI and AIDs during the same calendar month. To complete the study, a survey about PPIs prescription has been proposed to cancer specialists from B and PL areas during 15 days last December. Results: 2309 patients, mean age of 62.9 y (2-93) have been treated with TKIs in 2016 in the PL area. 6.6 dispensings have been done per patient. 795 pts (34%) had no AID dispensing. 274 pts (12%) had no concomitant dispensing of AID and TKI. 1240 pts (54%) had at least one concomitant dispensing. 67% of these patients had a concomitant dispensing of PPIs and 25% a concomitant prescription throughout the TKI treatment. Among these concomitant takes, 34% showed no interaction, 23% showed interactions (34% unknown cases, 9% diverging data). Data from the Bretagne area will be shown at the meeting. 43 clinicians have answered the survey about PPI prescription: 98% have prescribed them. The major reasons were: treatment of gastroesophageal reflux disease (88%), prevention/treatment of NSAID-associated ulcers (67%) or of esophageal duodenal and stomach ulcers (55%), for unknown reasons (31%), and for Zollinger-Ellison syndrome (31%). Duration of treatment was between 7 days and 2 months. Conclusions: Drug-Drug Interaction (DDI) analyses would be performed to underline for which TKIs, TKIs-PPIs interaction was the most harmful. Clear practice tools should be created to help clinicians to evaluate this DDI and what to do for their patients. Guidelines will be presented at the meeting. Legal entity responsible for the study: Cancer Observatory, OMEDIT B and PL. Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest.