To describe case series of new embolic stroke development in five active cancer patients on Apixaban

Direct Oral Anticoagulants (DOACs) have been widely used to prevent thromboembolic events in atrial fibrillation and DVT treatment. However, the efficacy remains to be studied in the cancer subgroup and the role of DOAC in cancer patients is inconclusive. We present a case series study of Apixaban failure in five patients with underlying malignancies resulting in acute embolic stroke.

This is an observational case series study at an academic hospital.

We identified five patients currently on Apixaban treatment for history of either atrial fibrillation or pulmonary emboli presenting with stroke-like symptoms. MR imaging of the brain was consistent with acute stroke of embolic appearance. CT angiogram of the head and neck showed no clinically significant stenosis or occlusions. Cardiac ultrasound did not reveal any patent foramen ovale or thrombus. Further stroke work-up with body imaging and/or tissue biopsy revealed active malignancies in all five patients. Those malignancies include high-risk smoldering IgG lambda multiple myeloma, metastatic lung adenocarcinoma, metastatic prostate cancer, squamous cell carcinoma, and pancreatic adenocarcinoma. Patients were found to have an underlying hypercoagulable state related to their malignancies. Apixaban was then discontinued and considering the potential drug-to-drug interaction from Warfarin with chemotherapy, we transitioned to therapeutic low-weight molecular heparin (LMWH) afterward. 

Our observational study indicates specifically blocking factor Xa or thrombin may not be sufficient in malignancy given the multiple mechanisms involved in cancer-induced coagulopathy. Further research is needed to identify optimal management strategies for anticoagulation in active cancer patients. We believe patients are likely to benefit from anticoagulation with LMWH and it should be continued at least until the cancer is in remission.