P-103: Real World Data on Efficacy and Safety of Low-Dose Direct Oral Anticoagulants (DOACs) for Venous Thromboembolism (VTE) Prophylaxis in Newly Diagnosed Multiple Myeloma

Introduction: VTE risk is high in newly diagnosed multiple myeloma (NDMM) patients, especially within the first 6 months of treatment. SAVED and IMPEDE scores assess risk and NCCN guidelines recommend their use. Few studies explore thromboprophylaxis by risk category and induction regimen leading to varied treatments. We share our institutional experience using DOACs vs aspirin in NDMM patients and explore incidence of VTE, patient safety, and utility of SAVED and IMPEDE scores.

Methods: NDMM patients aged 18+ from January 2018 to June 2022 were included. Those on anticoagulation for other indications or unable to safely take aspirin or DOACs were excluded. Primary outcome was VTE incidence in the first 6 months of therapy. Secondary outcomes were safety of low dose DOAC therapy, comparison of VTE scoring calculators (SAVED vs IMPEDE VTE), and patient and treatment factors. Fisher’s exact test and Wilcoxon rank sum tests compared characteristics for 6-month VTE status. Subgroup analyses examined factors related to 6-month VTE incidence in patients that received daratumumab based induction, Carfilzomib, Lenalidomide, dexamethasone (KRD), all other induction regimens, and those with high risk cytogenetics. Major and minor bleeding were defined by the International Society on Thrombosis and Hemostasis (ISTH).

Results: A total of 364 NDMM patients were included. Of these, 20% experienced VTE within 6 months. Of those who took aspirin, 20% had 6-month VTE. For DOACs, 21.2% had 6-month VTE. The overall cohort (P=0.96), subgroup analyses of patients who received daratumumab containing induction(P=0.82), KRD induction (P=0.51), all other induction (P=0.38), and those with high risk cytogenetics (P=0.70), showed no significant difference in 6-month VTE rate between aspirin or DOAC groups. Patients with SAVED score ≥2 or prior VTE history had significantly higher 6-month VTE rates in the overall cohort, those receiving regimens other than KRD or daratumumab containing induction, and those with high-risk cytogenetics (P< 0.01). Characteristics of age >80, sex, race, BMI >25, IMPEDE score, existing use of aspirin or low molecular weight heparin, or transplant status showed no significant difference in 6-month VTE in the overall cohort and in all subgroup analyses. There was a significant difference in minor bleeding with rates of 12.1% of the DOAC group and 2.5% of the aspirin group (P< 0.01). There was no significant difference in major bleeding events.

Conclusions: This large review highlights real-world efficacy and safety of DOACs in NDMM. Choice of VTE prophylaxis didn’t affect 6-month VTE rate, but DOAC use did cause more minor bleeding. Patients with SAVED score ≥2 and prior VTE history did have statistically significant increase in 6 month VTE rates overall and in all subgroups. Our study emphasizes that patient and treatment factors influenced 6-monthVTE incidence, while DOAC choice didn’t. Trials evaluating risk-assigned thromboprophylaxis in patients with MM should build upon this data.