Lenalidomide raises clot risk in multiple myeloma patients

Thromboembolic events are increased in patients undergoing lenalidomide-based therapy for multiple myeloma. Aspirin prophylaxis appears to reduce this risk.

"There is a real risk of blood clots with the use of lenalidomide in myeloma," according to Dr. S. Vincent Rajkumar, "particularly in combination with other chemotherapeutic drugs."

To investigate these and other risk factors, Dr. Rajkumar of the Mayo Clinic College of Medicine, Rochester, Minnesota and colleagues conducted a pooled analysis of data from three clinical trials involving 125 patients who had previously untreated multiple myeloma.

Along with lenalidomide-based therapy, 52 received high-dose dexamethasone (40 mg 12 days a month) and 73 received prednisolone or dexamethasone 40 mg, 4 times per month. In addition, 110 were given thromboprophylactic treatment, primarily aspirin.

Overall, 10 patients (8%) developed deep vein thrombosis (DVT), the investigators report in the April 1 issue of Cancer. Four were not receiving thromboprophylactic treatment at the time of the event.

There was no significant difference in the incidence of DVT in patients receiving concomitant erythropoietin therapy and those not receiving this treatment. The rate of DVT was higher in the high-dose corticosteroid group compared with the low-dose group (12% versus 6%, respectively), but this difference did not reach statistical significance.

The rate of thrombosis was lower than the range reported in the literature, the investigators point out, possibly because most patients were receiving anticoagulant prophylaxis and 58% received low-dose corticosteroid.

"The best prophylaxis," Dr. Rajkumar concluded, "should take into account all the risks and benefits. By using a low dose of steroids, and using aspirin as a preventive measure, the risk of blood clots can be minimized to less than 10%."