Infrequent transition to direct oral anticoagulants in patients with cancer

INTRODUCTION. Pharmacokinetic drug-drug interactions (DDIs) are challenging aspects of direct oral anticoagulant (DOAC) therapy in patients with cancer. We evaluated the prevalence of potential DOAC/antineoplastic agent DDIs and the one-year cumulative incidence of switching from low-molecular-weight heparin (LMWH) to a DOAC in patients with cancer. METHODS. Patients with cancer and an indication of LMWH were included from Herlev and Gentofte Hospital, Denmark, in the 2014-2019 period. Follow-up was initiated when the first dose of LMWH was dispensed. Data were obtained from electronic medical records. One-year cumulative incidence of switching from LMWH to DOAC was estimated using the Aalen-Johansen estimator. Potential DDIs were evaluated using a report from the European Heart Rhythm Association (EHRA) and a review by Hellfritzsch et al. RESULTS. A total of 161 patients were included with a median age of 70.8 (interquartile range: 64.2-76.1) years. The one-year cumulative incidence of switching from LMWH to DOAC was 32% (95% confidence intervals: 21-43%) in patients eligible for DOACs. Using the EHRA report, a total of 24% of antineoplastic agents were not identified. This percentage decreased to 8% using data from Hellfritzsch et al. CONCLUSIONS. In patients with cancer, the one-year cumulative incidence of switching from LMWH to DOAC was < 35% in patients eligible for DOAC, revealing a potential for improved anticoagulant treatment. Furthermore, contemporary data elaborated on potential DDIs between DOACs/antineoplastic agents.