(60) Trends of Thromboprophylaxis Among Newly Diagnosed Multiple Myeloma Patients Initiating Immunomodulatory Drug-Based Regimens, 2010 to 2018

Publication Number: 391

Background: The risk of developing venous thromboembolic events (VTE) is high among multiple myeloma (MM) patients. Moreover, MM therapies such as cytotoxic chemotherapy, immunomodulatory drugs (IMiDs), high-dose dexamethasone can further increase VTE risk. To mitigate this risk, clinical guidelines recommend initiating thromboprophylaxis regimens in MM patients. However, with no standard and agreed-upon thromboprophylaxis practice for MM patients, medications can range from prescribing aspirin to anticoagulant regimens with direct oral anticoagulants (DOAC) and warfarin.

Objectives: We aimed to describe warfarin- and DOAC-based thromboprophylaxis trends among newly diagnosed MM patients initiating IMiD-based treatment.

Methods: We designed a retrospective cohort study using the IBM MarketScan Commercial Claims and Encounters and Medicare Supplemental databases. We built a cohort of incident MM patients receiving IMiD-based treatment at anytime between 2010 and 2018 with at least 12 months of continuous enrollment before and after MM diagnosis. We collected information on comorbidities, VTE risk factors, and other MM therapies. The primary outcome of interest was initiating thromboprophylaxis with warfarin or DOAC within 90 days of treatment initiation. We evaluated prescribing trends over time and characteristics associated with DOAC- or warfarin-based thromboprophylaxis. We used univariate and multivariate multinomial logistic regression models comparing these two forms of thromboprophylaxis to those who did not receive thromboprophylaxis.

Results: From 2010 to 2018, 6739 MM patients were on IMiD-based regimens. Their median age was 62 years, and 43% were female. Overall, warfarin-based thromboprophylaxis was more prevalent than DOACs (10% vs. 7.5%). However, we observed an increase in the DOAC-based thromboprophylaxis uptake from 2.4% of patients in 2010 to 14.6% in 2018; and the use of warfarin-based thromboprophylaxis consistently declined over time from 16.3% of patients in 2010 to 3.9% in 2018. These annual increasing trends for DOAC-based regimens and decreasing trends for warfarin-based regimens were robust after adjusting for demographic and clinical characteristics, including VTE risk factors and other MM treatment modalities (DOAC: OR 1.34, 95% CI 1.28-1.41 and warfarin: OR 0.82, 95% CI 0.78-0.86).

Conclusions: Over the study period, our findings suggest an increase in using DOAC-based thromboprophylaxis regimens for MM patients receiving IMiD therapy at the expense of warfarin-based regimens. Further research is needed to determine whether these trends are associated with differences in clinical outcomes.