Impact of venous thromboembolism on survival in multiple myeloma patients receiving bispecific antibody therapy: Insights from real-world data.

7521 Background: Patients with multiple myeloma (MM) have a significantly higher risk of venous thromboembolism (VTE), up to 20 times greater than the general population. This risk is influenced by the disease, anti-myeloma treatments, and patient-related factors. However, there is limited information regarding the rates of VTE and survival outcomes with FDA-approved bispecific antibodies (BsAbs) such as teclistamab, elranatamab, and talquetamab. This study aims to assess these endpoints using real-world data (RWD). Methods: A retrospective, multicenter RWD analysis was conducted using the TriNetX database on Jan 17, 2025. Two cohorts were analyzed: 1) MM patients who have been treated with one of the FDA-approved BsAbs (teclistamab, elranatamab, or talquetamab) and who developed VTE (deep vein thrombosis or pulmonary embolism) within 18 months from initiation of BsAb treatment, 2) MM patients treated with the same BsAbs who did not develop VTE in the same time frame. Kaplan-Meier analysis, log-rank test, hazard ratios (HR), risk ratios (RR), and 95% confidence intervals (CI) were used to assess the primary outcomes, which were overall survival and risk of VTE development. Propensity score matching was used to control the impact of specific known confounders. Results: We identified 1530 MM patients treated with the aforementioned BsAbs and had data available regarding VTE development within 18 months of treatment initiation. The patients’ mean age at the index event (treatment initiation and VTE) was 69±9.9 years, and 52.2% were males. The rate of VTE was 8.5% (n=130). The MM patients treated with BsAbs and developed VTE had a statistically significant higher risk of death compared to the patients without VTE (RR 1.475, 95% CI 1.117-1.946). The MM patients with VTE had statistically significantly shorter overall survival and higher risk of death (526 days vs. not reached median survival, 49.83% vs. 65.61% survival probability at 18 months, log-rank test p=0.003; HR 1.667, 95% CI 1.193-2.329). After propensity score matching for covariates [accounting for age, sex, ECOG, BMI, COVID-19, pneumonia types, certain infectious diseases, hypertensive diseases, surgery, and medications (dexamethasone, epoetin alfa, darbepoetin alfa)] although RR lost statistical significance (RR 1.333, 95% CI 0.888-2.001), the MM patients with VTE still had statistically significantly shorter overall survival and higher risk of death (50.07% vs. 72.27% survival probability at 18 months, log-rank test p=0.007; HR 1.989, 95% CI 1.190-3.325). Conclusions: RWD demonstrated that MM patients treated with BsAbs who developed VTE had a higher risk of death and shorter overall survival. Further analysis, possibly evaluating patient-level data on a larger cohort of patients with more sophisticated confounding controls, is needed to further clarify this finding.