7074 Background: Venous thromboembolism (VTE) is a major cause of morbidity and mortality among cancer patients. The Apixaban for the Prevention of Venous Thromboembolism in High-Risk Ambulatory Cancer Patients (AVERT) randomized controlled trial concluded that apixaban is a safe and effective option for VTE prophylaxis in high-risk ambulatory cancer patients initiating a new chemotherapy regimen. We performed a cost-effectiveness analysis from a health system perspective to determine if apixaban is a feasible prophylactic strategy for this population. Methods: A decision model was created from a third party payer perspective with a time horizon of 6 months, based on the treatment arms of the AVERT trial: (1) apixaban 2.5 mg twice daily for 6 months during active chemotherapy versus (2) placebo. Rates of VTE (4.2% apixaban vs 10.2% placebo), major bleeding (3.5% vs 1.8%) and clinically relevant nonmajor bleeding (CRNMB) (7.3% vs 5.5%) were modeled from the results of the AVERT trial. Cost estimates for treatments and events were obtained from wholesale drug costs, previously published studies and Medicare reimbursement data, and adjusted for inflation to 2018 dollars. Quality adjusted life years were calculated based on previously published utility values for the health states of advanced cancer, DVT, PE, and major bleeding events. An exploratory analysis was performed comparing prophylactic aspirin to no prophylaxis assuming a VTE rate of 7.2%, major bleeding rate of 3.5%, and CRNMB rate of 7.3%, based on the conservative assumptions that while aspirin may not be as effective at preventing VTE, the rate of clinically significant bleeding events would be similar or greater than that of apixaban. Results: In the base case model, apixaban is more costly and more effective than placebo (ICER = $5,013,190/QALY), and the cost per VTE prevented in the apixaban arm is $33,000. In one-way sensitivity analysis, if the cost of apixaban were reduced by 40% from $3,197 to $1,250 for a 6 month course, this could potentially be a cost-effective prophylaxis strategy with an ICER less than $100,000/QALY. In the alternative analysis, aspirin dominates placebo as it is both more effective and less expensive, and remains cost-effective even when the rate of clinically recognized bleeding with aspirin exceeds 15%. Conclusions: Further investigation into less costly prophylactic options such as generic direct oral anticoagulants (once available) and aspirin is warranted prior to broader implementation of a VTE prophylaxis strategy in this population.
P493 Cost-effectiveness of venous thromboembolism prophylaxis after hospitalization in patients with Inflammatory Bowel Disease
