Abstract Number: PB2105
Meeting: ISTH 2020 Congress
Theme: Venous Thromboembolism and Cardioembolism » Cancer Associated Thrombosis
Background: Patients with active cancer have an increased risk of venous thromboembolism (VTE) complications which is associated with morbidity, mortality and significant health care costs. The AVERT trial demonstrated that prophylactic doses of apixaban (2.5 mg twice-daily) significantly decreased the rate of VTE when compared to placebo in intermediate-to-high risk (Khorana score >2) patients starting chemotherapy. The efficacy of apixaban in different subgroups of cancer patients remains unclear.
Aims: We sought to evaluate the risk of VTE in different subgroups of ambulatory patients initiating chemotherapy.
Methods: This is a pre-planned post-hoc analysis of the AVERT trial, which was a randomized, placebo-controlled, double-blind clinical trial. Hazard ratios with 95% confidence intervals (CI) were calculated using the Cox proportional hazards model to compare the treatment effect accounting for clustering at center level. Subgroup analyses were based pre-defined subgroups including: age, gender, race, weight, prior VTE, creatinine clearance, antiplatelet therapy, cancer characteristics, bevacizumab use, and baseline ECOG status.
Results: During the study period, VTE events occurred in 40 (7.1%) patients: 4.2% and 10.2% of the apixaban and placebo groups, respectively [HR 0.41; 95%CI, 0.26-0.65]. Patient characteristics associated with decreased VTE rates included: age < 75 [HR 0.37; 95%CI, 0.24-0.59]; male sex [HR 0.25, 95%CI 0.12-0.48], weight >90Kg [HR 0.18, 95%CI, 0.06-0.52]; and no prior history of prior VTE [HR 0.41, 95%CI 0.26-0.64]. Cancer characteristics associated with decreased rates of VTE with apixaban included solid cancers [HR 0.30; 95%CI, 0.19-0.47] and metastatic disease [HR 0.45; 95%CI, 0.26-0.78]. Concurrent use of antiplatelet therapy was also associated with decreased VTE rates [HR 0.18, 95%CI 0.10-0.33).
Conclusions: In the AVERT trial, apixaban thromboprophylaxis provided significantly decreased risk of VTE in patients with age< 75, male sex, weight >90Kg, no prior VTE, solid cancer, and metastatic disease. (Funded by the Canadian Institutes of Health Research and Bristol-Myers Squibb-Pfizer Alliance; NCT02048865.)
[Incidence of venous thromboembolism during the study period]
To cite this abstract in AMA style:
Nayak AL, Zahrai A, Mallick R, Carrier M, Wells P. Risk of venous Thromboembolism among Subgroups of Cancer Patients Undergoing Chemotherapy: Post-Hoc Analysis of the AVERT Trial [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/risk-of-venous-thromboembolism-among-subgroups-of-cancer-patients-undergoing-chemotherapy-post-hoc-analysis-of-the-avert-trial/. Accessed March 22, 2024.« Back to ISTH 2020 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/risk-of-venous-thromboembolism-among-subgroups-of-cancer-patients-undergoing-chemotherapy-post-hoc-analysis-of-the-avert-trial/