Bleeding and thrombotic events in patients with colorectal cancer treated with bevacizumab and receiving novel oral anticoagulants and antiplatelet medications.

Abstract

104 Background: Bevacizumab is a humanized monoclonal VEGF antibody given in combination with fluorouracil-based chemotherapy for metastatic colorectal cancer (mCRC). Many patients with mCRC also have cardiovascular comorbidities requiring anticoagulation or antiplatelet therapy. The bleeding and thrombotic event rates in the setting of concurrent novel oral anticoagulants (NOACs) and bevacizumab treatment in patients with mCRC remain unclear. Methods: 462 patients with mCRC at Barnes-Jewish Hospital were identified between December 1, 2016 and December 1, 2021 and screened for concurrent treatment with bevacizumab and anticoagulant or antiplatelet therapy. Demographic and clinical information was extracted by electronic chart review. Results: 21 patients were identified who received bevacizumab and either apixaban or rivaroxaban for mCRC treatment. Aspirin was prescribed in some of these patients within 3 years of starting apixaban or rivaroxaban. Of the 13 patients who had no history of aspirin prescription, 9 were given apixaban, and 4 were given rivaroxaban while on bevacizumab. 44.4% of the patients who received apixaban experienced bleeding. All these events were epistaxis, and only 25% of the cases resulted in any treatment discontinuation. 75% of the patients who received rivaroxaban experienced bleeding events, which 33.3% of the time resulted in discontinuation of either rivaroxaban or bevacizumab. We also looked at 8 patients who had received aspirin in the last three years: 7 patients were on apixaban, and one was on rivaroxaban while on concomitant aspirin and bevacizumab. 28.6% of the patients who received apixaban with bevacizumab and aspirin experienced an adverse bleeding event that resulted in some form of treatment discontinuation. Meanwhile, the patient who received rivaroxaban with bevacizumab and aspirin experienced a bleeding event that resulted in discontinuation of a medication. No patient experienced any adverse thrombotic events. Conclusions: Patients with mCRC treated with bevacizumab and apixaban with no history of prior aspirin use within three years have a relatively low risk of developing bleeding events that warrant treatment discontinuation. The addition of NOAC to bevacizumab therapy does not appear to increase the risk of adverse thrombotic events.