PO34 | INVESTIGATORS’ DECISIONS ON ANTICOAGULATION AFTER EXTENDED API-CAT TREATMENT FOR CANCER VENOUS THROMBOEMBOLISM

I. Mahé^1|4, F. Happe², M. Monreal^5|7, H. Robert-Ebadi⁸, P. Debourdeau⁹, J. R. Fabreguettes¹⁰, S. Accassat¹¹, P. Mismetti^4|11|12, P. Girard¹³, S. Laporte^4|12|14, C. Chapelle¹⁴ | ¹Paris Cité University; ²Assistance Publique - Hôpitaux de Paris, Louis Mourier Hospital, Department of Internal Medicine; ³Inserm UMR-S970, Paris Cardiovascular Research Center, Team « Endotheliopathy and Hemostasis Disorders », Paris, France; ⁴F-CRIN INNOVTE Network, France; ⁵Department of Internal Medicine, Institut de Recerca Germans Trias i Pujol, Hospital Universitari Germans Trias i Pujol, Badalona, Spain; ⁶Department of Medicine, Universitat Autonoma de Barcelona, Barcelona; ⁷Universidad Catolica San Antonio de Murcia, Murcia, Spain; ⁸Division of Angiology and Hemostasis, Faculty of Medicine, Geneva University Hospitals, Geneva, Switzerland; ⁹Arles Hospital, Oncology unit, Arles, France; ¹⁰Assistance Publique - Hôpitaux de Paris, AGEPS, France; ¹¹Service de Médecine Vasculaire et Therapeutique, CHU de Saint-Etienne, Saint-Etienne, France; ¹²Université Jean Monnet, Mines Saint-Étienne, INSERM Unité 1059, Santé Ingénierie Biologie Saint-Étienne SAINBIOSE, Saint-Étienne, France; ¹³Département de Pneumologie, Institut Mutualiste Montsouris, Paris; ¹⁴Service de Pharmacologie Clinique, CHU de Saint-Etienne, Saint-Etienne, France

Introduction. In the API-CAT trial, reduced-dose apixaban (2.5 mg twice daily) was non-inferior to full-dose apixaban (5 mg twice daily) for preventing recurrent venous thromboembolism (VTE) and was associated with fewer clinically relevant bleeding events. These results are expected to influence clinical practice, but real-world data on physicians’ anticoagulation management remain limited.

Aim. To describe investigators’ anticoagulant treatment decisions for patients enrolled in the API-CAT trial following study treatment discontinuation, prior to trial unblinding and communication of the results.

Materials and Methods. Post hoc, descriptive analysis of the prospective, multicenter, randomized, double-blind API-CAT trial. Patients who received at least one dose of study treatment were included. Investigators prospectively reported anticoagulant treatment decisions following discontinuation of apixaban (full or reduced dose) as study treatment, either prematurely or at the planned end of the trial: no anticoagulant, anticoagulant at reduced dose, or anticoagulant at full dose. Descriptive analyses examined treatment choices, dosing regimen, and patient, cancer, and context-related characteristics.

Results. Of the 1,766 randomized patients, 1,458 (82.6%) were included. Following study treatment discontinuation, clinicians decided to discontinue treatment in 198 patients (13.6%) or to continue in 1,260 (86.4%). Among them, 790 (62.7%) received full dosing, 465 (36.9%) reduced dosing, and 5 (0.4%) unknown dosing. Direct oral anticoagulants (DOACs) were prescribed in 89.6% and low-molecular-weight heparin in 9.9%. Decisions were broadly consistent across patient and cancer characteristics. However, the decision to discontinue anticoagulation was more frequent when study treatment was stopped during the trial vs. at the end (23.2% vs. 11.4%) and among oncology- vs. thrombosis-related specialties (22.2% vs. 10.5%). Practice also differed across countries.

Conclusions. Before API-CAT results were known, most investigators continued anticoagulation following study treatment discontinuation, mainly with DOACs—about two-thirds at full dose and one-third at reduced dose. Decisions appeared independent of patient or cancer characteristics but varied across countries and specialties. In light of API-CAT, broader adoption of reduced-dose apixaban for extended anticoagulation is anticipated; further research should identify patients who may safely discontinue therapy.