In patients with myeloma, thalidomide significantly improves outcomes but increases the risk of thromboembolic events. In this randomized, open-label, multicenter trial, we compared aspirin (ASA) or fixed low-dose warfarin (WAR) versus low molecular weight heparin (LMWH) for preventing thromboembolism in patients with myeloma treated with thalidomide-based regimens.

A total of 667 patients with previously untreated myeloma who received thalidomide-containing regimens and had no clinical indication or contraindication for a specific antiplatelet or anticoagulant therapy were randomly assigned to receive ASA (100 mg/d), WAR (1.25 mg/d), or LMWH (enoxaparin 40 mg/d). A composite primary end point included serious thromboembolic events, acute cardiovascular events, or sudden deaths during the first 6 months of treatment.

Of 659 analyzed patients, 43 (6.5%) had serious thromboembolic events, acute cardiovascular events, or sudden death during the first 6 months (6.4% in the ASA group, 8.2% in the WAR group, and 5.0% in the LMWH group). Compared with LMWH, the absolute differences were +1.3% (95% CI, -3.0% to 5.7%; P = .544) in the ASA group and +3.2% (95% CI, -1.5% to 7.8%; P = .183) in the WAR group. The risk of thromboembolism was 1.38 times higher in patients treated with thalidomide without bortezomib. Three major (0.5%) and 10 minor (1.5%) bleeding episodes were recorded.

In patients with myeloma treated with thalidomide-based regimens, ASA and WAR showed similar efficacy in reducing serious thromboembolic events, acute cardiovascular events, and sudden deaths compared with LMWH, except in elderly patients where WAR showed less efficacy than LMWH.