PB0460 - Evaluation of edoxaban plasma concentration data from clinical practice.

Background: Edoxaban prescribing is increasing in popularity in the United Kingdom. However, the latest guidance from the International Society of Thrombosis and Haemostasis suggests avoiding in patients >120kg or with a BMI >40kg/m2 for the treatment of venous thromboembolism. Data describing edoxaban exposure in this population are lacking and complicated by reported reduced efficacy in those with a high creatinine clearance in the atrial fibrillation population.

Aims: To report an analysis of edoxaban plasma concentration data from clinical practice and describe edoxaban exposure in those with high bodyweight (>120kg) or high creatinine clearance (90mL/min).

Methods: Between 2017 and 2020, edoxaban plasma concentrations drawn from patients attending the anticoagulation clinic at King’s College Hospital, London as part of routine care were retrospectively reviewed, with patient characteristics collated from the electronic patient record. Edoxaban concentrations were determined using an anti-Xa chromogenic assay (Diagnostica Stago), which has a lower limit of quantification (LLOQ) of 20ng/mL. A trough concentration was defined as a level drawn after 20 hours post dose.

Results: 279 edoxaban plasma concentrations were drawn from 257 patients. The majority of patients were anticoagulated for stroke prevention in AF (91.8%) – Table 1. 104/279 trough concentrations were reported, 43/104 (41%) of which were LLOQ (Figure 1). 5/8 (63%) of patients >120kg and 18/37 (49%) of those with a creatinine clearance >90mL/min had a reported trough less than 20ng/mL (LLOQ).

Conclusion(s): A high proportion of edoxaban trough concentrations were reported as LLOQ from clinical practice data. How this relates to outcomes requires further investigation and further work is required on the influence of body weight and renal function on edoxaban pharmacokinetics.