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

Background: Bevacizumab is a humanized monoclonal anti-VEGF antibody often given in combination with fluorouracil-based chemotherapy as therapy for metastatic colorectal cancer (mCRC). The bleeding and thrombotic event rates in the setting of concurrent novel oral anticoagulants with and without aspirin 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 three years of starting apixaban or rivaroxaban. Of the 13 patients without aspirin prescription, nine were given apixaban, and four were given rivaroxaban while on bevacizumab. Four out of nine of the patients who received apixaban had epistaxis, and only one case resulted in any treatment discontinuation. Three out of four of the patients who received rivaroxaban experienced bleeding, and one of these three patients discontinued bevacizumab. We also looked at eight patients who had received aspirin. Two out of seven patients who received apixaban/bevacizumab/aspirin experienced bleeding and discontinued a medication. The patient who received rivaroxaban/bevacizumab/aspirin experienced bleeding and discontinued bevacizumab. No patient experienced adverse thrombotic events. Conclusions: Patients with mCRC treated with bevacizumab and apixaban with no history of aspirin use within three years have a relatively low risk of bleeding that warrants treatment discontinuation.