Rivaroxaban or Aspirin As Thromboprophylaxis in Multiple Myeloma

Hematological cancer has risk of venous thromboembolism of 28 fold compared to sex and age adjusted incidence in general population (JAMA 2005;293:715-722). This risk increases in patients with MM receiving dexamethasone and immunomodulatory drug. Thus, thromboprophylaxis with aspirin in low risk patients and LMWH or warfarin in high risk patients are recommended (Leukemia 2008;22:414-423). Direct oral anticoagulants are promising due to their convenience and costs-effectiveness in preventing VTE in other settings. They have not been extensively studied in myeloma therapy.

From January of 2010 to December of 2017, 105 with MM received thalidomide and dexamethasone based triplet induction therapy, maintenance with thalidomide and creatinine clearance > 30 mL/min. From those, 23 (21.9%) had only an additional risk factor and were randomized 5:1 to receive 100 mg aspirin or 10 mg rivaroxaban until relapse and need another treatment. Doppler ultrasound was performed every six months or as medical indication in all patients and pulmonary CT scan if EP was suspected.

Five patients received rivaroxaban, 3 males and 2 females, median age of 67.5 years; additional factors were obesity in 4 and DM in one. Aspirin was received by 18 patients, 10 males an 8 females, median age 66.8 years; additional factors were obesity in 10, DM in 5, erythropoietin in 3.

No patient in the Rivaroxaban arm developed thrombosis; bleeding episodes were self-limited to the gums and easy bruising; no major bleeding was detected. One patient in the Aspirin arm, with body mass index of 31.22 kg/m2 as an additional risk factor, developed right iliofemoral DVT without PE; he was changed to rivaroxaban at therapeutic doses for six months with resolution of the DVT and then continue with 10 mg dose; bleeding episodes in all patients were similar to the rivaroxaban arm.

In this small group of patients with a low risk factors with an additional one, that could be in an intermediate risk, the use of rivaroxaban showed a good efficiency and security profiles. Either, rivaroxaban or aspirin could be used in this situations and deserve further investigation.