Primary prevention of venous thromboembolism with apixaban for multiple myeloma patients receiving immunomodulatory agents.

Immunomodulatory drugs (IMiDs) have improved survival of patients with multiple myeloma (MM) and comprise the therapeutic backbone at all phases of therapy. Although well-tolerated, IMiDs increase rates of venous thromboembolism (VTE). In this phase IV, single-arm pilot study, fifty patients with MM on IMiDs received apixaban 2·5 mg orally twice daily for primary prevention of VTE and were prospectively monitored for six months. The primary safety outcomes were rates of major haemorrhage and clinically relevant non-major haemorrhage over six months. The primary efficacy outcome was the rate of symptomatic VTE over six months. IMiDs used were lenalidomide (58%) or pomalidomide (42%). During the six-month evaluation period, no patients experienced major haemorrhage or VTE. Three patients experienced clinically relevant, non-major haemorrhage which was managed medically, and all were able to resume apixaban. One patient stopped therapy shortly after initiation due to an allergic reaction to apixaban. No patients experienced stroke, myocardial infarction, or death. In this pilot study, low-dose apixaban was safe and well-tolerated as a primary prevention therapy of VTE for patients with MM receiving IMiDs. Further studies are needed to validate low-dose apixaban as a standard primary prevention anti-thrombotic strategy for patients with MM receiving IMiDs.