Abstract 738: Increasing uptake of direct oral anticoagulants for thromboprophylaxis among newly diagnosed multiple myeloma patients initiating immunomodulatory drug-based regimens, 2010 to 2017
Authors: Abdelaziz Abdullah I. , Sweiss Karen , Patel Pritesh R. , Chiu Brian C-H , Calip Gregory S. 
Published: June 2022

Abstract
Background: Multiple myeloma (MM) is associated with an increased incidence of venous thromboembolism (VTE) which results in greater morbidity and mortality in MM patients. Several MM treatments including receiving immunomodulatory drugs (IMiDs), cytotoxic chemotherapy, and high-dose dexamethasone also increase VTE risk. Clinical guidelines recommend thromboprophylactic regimens to mitigate the risk of VTE in MM patients. However, practices vary with respect to medications used for thromboprophylaxis, ranging from prescribing of aspirin to anticoagulant regimens with direct oral anticoagulants (DOAC) and warfarin. We aimed to describe patterns of warfarin- and DOAC-based thromboprophylaxis in newly diagnosed MM patients initiating IMiD-based treatment.
Methods: We conducted a retrospective cohort study of MM patients using the IBM MarketScan Commercial Claims and Encounters and Medicare Supplemental databases. We included newly diagnosed MM patients initiating IMiD-based treatment between 2010 and 2017 with continuous health plan enrollment 12 months prior to and following 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: In a cohort of 6227 MM patients initiating IMiD-based regimens, the median age was 62 years and 43% were female. Over the entire study period, warfarin-based thromboprophylaxis was more prevalent relative to DOACs (10.5% vs. 6.9%). However, we observed a trend of increasing adoption of DOAC thromboprophylaxis from 2.4% of patients in 2010 to 12.7% in 2017; and the use of warfarin thromboprophylaxis consistently declined over time from 16.5% of patients in 2010 to 3.2% in 2017. In multivariable analyses, trends associated with increasing or decreasing odds of thromboprophylaxis with these agents were robust after adjustment for demographic and clinical characteristics including VTE risk factors and other MM treatment (DOAC: OR 1.35, 95% CI 1.28-1.44 and warfarin: OR 0.81, 95% CI 0.77-0.86).
Conclusions: Over the study period, our findings indicate that DOAC-based thromobprophylaxis regimens were increasingly used over warfarin-based treatment in newly diagnosed commercially insured MM patients initiating IMiD therapy. Further research is needed to determine whether these patterns are associated with differences in clinical outcomes.
Citation Format: Abdullah I. Abdelaziz, Karen Sweiss, Pritesh R. Patel, Brian C-H Chiu, Gregory S. Calip. Increasing uptake of direct oral anticoagulants for thromboprophylaxis among newly diagnosed multiple myeloma patients initiating immunomodulatory drug-based regimens, 2010 to 2017 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 738.