PB0967 - Real World management of cancer associated thrombosis: how many patients actually receive DOACS?

Background: Clinical guidelines recommend direct acting oral anticoagulants (DOACs) first-line in the treatment of cancer associated thrombosis (CAT), subject to safety caveats and clinical indications. Of the phase III studies comparing DOACs with dalteparin for the treatment of CAT, 50% of those screened did not meet the study inclusion criteria. Consequently, the extent to which DOACs can safely replace low molecular weight heparins in the management of CAT remains unclear.

Aims: To evaluate the proportion of patients for whom DOACs are safe and indicated as first line anticoagulant.

Methods: In this 12 month prospective observational study, sequential patients presenting to a regional CAT service were reviewed, with the intention of commencing/ converting eligible patients to the regional DOAC of choice: apixaban. Clinical decisions were made according to clinical guidelines, published trial data and drug licence.

Results: Of 287 patients reviewed, apixaban was considered appropriate in 100 (35%). Reasons for not using apixaban were cited as either safety reasons (n=106, 37%) or lack of trial evidence/ licence (n=81, 28%). Contraindications on the grounds of safety included in-situ primary upper gastro-intestinal or urothelial cancer (n=37, 13%), significant drug-drug interactions (DDI) (n=33, 11%) and recent bleeding or bleeding risk (n=33, 11%). Lack of evidence or licence included non-lower limb venous thrombosis e.g. splanchnic vein or primary / secondary CNS malignancy (n=30, 10%), PICC related thrombosis or superficial vein thrombosis (n=51, 18%).

Conclusion(s): Our data suggests most patients presenting to a regional CAT service are not be treated with a DOAC due to safety concerns or lack of available evidence for the presenting clinical indication. Some DDIs could be avoided by prescribing edoxaban and it is possible that efficacy data will emerge to support unlicenced indications. However, this will still leave over one third of CAT patients with contraindications to DOACs.