Are Oral Anticoagulants Effective Against VTE in Patients with Multiple Myeloma?

According to data presented at the 2020 American Society of Hematology Annual Meeting & Exposition, the use of direct oral anticoagulants (DOACs) effectively prevented venous thromboembolism (VTE) in patients with multiple myeloma (MM) receiving immunomodulatory drugs (IMiDs) at similar rates to other anticoagulation regimens.

Individuals with MM are at increased risk for developing VTE, or blood clots in the veins. Guidelines for cancer associated VTE recommend treatment with aspirin for patents with low clotting risk and a regimen of low molecular weight heparin (LMWH) for patients at high risk. Less data is available on the use of oral anticoagulants in cancer patients, particularly those with MM on IMiDs. In this study, researchers sought to assess the efficacy and safety of DOACs for VTE prophylaxis compared to other regimens for this patient population.

This retrospective study enrolled 200 patients being treated for MM with IMiDs at the Dana Farber Cancer Center in Massachusetts. Four VTE prophylaxis regimens were compared: aspirin, LMWH, warfarin, and DOACs. Primary endpoints were the 6-month rate of symptomatic VTE and any major and clinically relevant bleeding. Secondary endpoints included risk assessment and factors for VTE and bleeding.

In total, 334 prophylactic regimens were included during treatment with IMiDs: 160 aspirin, 51 LMWH, 42 warfarin, and 81 DOACs. The investigators found no significant different in rates of VTE or bleeding events among the four subgroups. Upon subgroup analysis of patients at high risk for VTE, data showed that use of DOACs significantly reduced risk for these events.

Patients with a body mass index greater than 25 kg/m2 and prechemotherapy white blood cell count of more than 11k showed an increased risk of VTE events. Bleeding events were associated with age over 80 years and concurrent use of nonsteroidal anti-inflammatory drugs. History of atrial fibrillation was shown to be protective against VTE.

“Use of DOACs as a VTE prophylaxis regimen in multiple myeloma patients taking IMiDs was found to be as safe as other recommended prophylactic regimens with a trend towards improved efficacy,” the researchers concluded. “Our data provide a novel strategy for VTE prevention in myeloma: To anticoagulate all patients on IMiDs except those at risk for bleeding.”