Frequency of venous thrombotic events in patients with myelodysplastic syndrome and 5q deletion syndrome during lenalidomide therapy.

Lenalidomide is known to increase the risk of venous thromboembolism in patients with hematologic malignancies. The role of antithrombotic prophylaxis in patients receiving lenalidomide is well established in multiple myeloma. However, when used in patients with a myelodysplastic syndrome (MDS)-in particular, del(5q) patients-the risk of venous thromboembolism and the need for anticoagulation are unknown. We performed a retrospective for MDS patients with 5q deletion. The total number of patients was 64, and 24 (38%) were treated with lenalidomide. Of those who received lenalidomide, venous thrombotic events (VTE) occurred in 4 (17%). All events occurred after 1 year of lenalidomide therapy. Although limited by the cohort size, concurrent erythropoietin-stimulating agents (ESAs) were not associated with increased thrombotic events, and the diagnosis of VTE did not affect survival. Our data suggest an increased incidence of VTE with prolonged lenalidomide treatment, mainly if MDS responds to this therapy.