The incidence of thromboembolism for lenalidomide versus thalidomide in older patients with newly diagnosed multiple myeloma.

It is uncertain if different immunomodulatory drugs (IMID) pose distinct thrombotic risk in patients with newly diagnosed multiple myeloma (MM). Among 2397 MM patients from the SEER-Medicare database from 2007 to 2013, 78% received lenalidomide, and 22% received thalidomide. After inverse probability weighting to balance confounders, the 12-month incidences of venous thromboembolism (VTE 10%) and arterial thromboembolism (ATE 5%) were similarly high in both groups. Lenalidomide versus thalidomide had a subdistribution hazard ratio of 1.11 (0.59-2.02) for VTE and a subdistribution hazard ratio of 0.96 (0.45-1.98) for ATE. Overall survival was not significantly different with a hazard ratio of 0.88 (0.60-1.18) for lenalidomide versus thalidomide. Concurrent anticoagulant prophylaxis was infrequently prescribed in < 20% of both groups. Our study demonstrates that despite improvement in myeloma-directed therapy and supportive care, thrombosis remains an important consideration for all IMID-treated MM patients. Appropriate risk stratification and vigilant thromboprophylaxis remain essential to prevent this complication.