Category: Professional Posters
Purpose: Patients that receive anticancer drugs are at risk of drug-drug interactions (DDIs). DDIs involving oral anticancer drugs can decrease their anticancer effectiveness or increase the risk of toxicities. The use of oral anticancer drugs has become widespread over the last decade and they present potential DDI risk owing to their chronic use. Many of them are associated with CYP metabolism and QT prolongation. However, limited information is available on the prevalence of DDIs involving oral anticancer drugs. We aimed to gain further insight into the real-world prevalence of clinically significant DDIs in patients treated with oral anticancer drugs in Korea.
Methods: Data from 2016 Health Insurance Review and Assessment Service-National Patients Sample (HIRA-NPS) of South Korea were searched for potential DDIs involving oral anticancer drugs. The drugs prescribed concomitantly with oral anticancer drugs were screened by using two international drug interaction databases: Lexicomp® Interactions module and Micromedex® solution database. Clinically significant DDIs were defined as DDIs with a severity rating of “major” or “higher”. DDIs were classified into category 1 (concordant severity rating) or category 2, based on the concordance of severity ratings between reference databases.
Results: Of the 14,352 patients prescribed anticancer drugs, 5,332 patients received oral anticancer drugs; with patients of ≥ 65 years of age and < 18 years of age accounting for 36.9% and 0.7%, respectively, of the total number of patients. Overall 2,861 cases of DDIs in 1,516 patients (26.7%) and 807 cases of category 1 DDIs in 509 patients (9.0%) were identified. The DDIs involving targeted agents comprised 42.6% and 70.4% of the overall and category 1 DDIs, respectively. The majority of DDIs concerns QT prolongation (34.6% of DDI cases), reduced exposure of antineoplastic agents (27.6%: 23.0% via absorption and 4.6% via metabolism), CNS toxicities (9.1%), bleeding risk (8.2%), and toxicities of antineoplastic agents due to inhibition of metabolism or excretion (7.9%). Pazopanib, methotrexate, gefitinib, dasatinib, and enzalutamide were the most frequently involved antineoplastic agents and H2 receptor antagonists, proton pump inhibitors and antacids were the most common counterpart drug classes in the category 1 DDIs.
Conclusion: This study showed that clinically significant potential DDIs with oral antineoplastic agents were prevalent in real-world practice. The recognition of this high prevalence of DDIs in patients taking oral antineoplastic agents is a necessary step to improve the clinical outcome.