What Is the Most Cost-Effective Position of Vedolizumab in Treatment Algorithms of Ulcerative Colitis From a Population Management Perspective?

Abstract

Introduction: Prior cost-effectiveness analyses assessing vedolizumab (VDZ) use in Ulcerative colitis (UC) have compared VDZ head to head with other biologic agents. In the real world, the mixed usage patterns of the more commonly used anti-TNFs, infliximab (IFX) and adalimumab (ADA), vary. We aimed to assess the ideal position for VDZ in UC treatment algorithms when accounting for the use of either IFX or ADA as the existing first line anti-TNF from a population management perspective. Methods: We employed aMarkov model to identify the most cost-effective position for VDZ in 3 different positions in a step-up treatment algorithm for UC (Figure 1): (A1) prior to initiating either combined IFX + azathioprine (AZA) or ADA+AZA, (A2) prior to combination therapy with a second anti-TNF, and (A3) last-line prior to colectomy. With each therapy, individuals could enter clinical remission or response, or develop a complication including infection, lymphoma, or other adverse events. Transition probabilities were derived from published clinical trials including ACT, GEMINI, SUCCESS, and ULTRA-2, stratified by prior exposures. Utilities and costs were derived from published estimates, Medicare reimbursement rates, the Nationwide Inpatient Sample, and wholesale acquisition costs. Primary analyses consisted of probabilistic simulations of 100,000 individuals at 1 year. Three separate analyses were conducted, with 50% IFX+AZA and 50% ADA+AZA use, 100% IFX+AZA use, and 100% ADA+AZA use. Threshold analyses was performed varying the existing treatment mix percentage between ADA and IFX to determine if this influenced the preferred strategy. All models assumed a willingness-to-pay (WTP) threshold of $100,000 per quality adjusted life year gained.636_A Figure 1. Overview of base model structureResults: In this model, the preferred strategy was VDZ used as first line biologic before an initial trial of combination therapy (A1) when ADA was used as the first anti-TNF for 50% or 100% of individuals, or VDZ use before cycling to a second anti-TNF if 100% of individuals used IFX as their first anti-TNF (Table 1). In threshold analysis, VDZ use was preferred prior to an anti-TNF for a UC population if >9% of individuals started with ADA. Conclusion: This model suggests that in moderate to severe UC, utilizing VDZ as the first biologic (prior to IFX+AZA or ADA+AZA) may be the most cost-effective strategy for payers in markets, particularly if >9% of individuals select ADA instead of infliximab as their first anti-TNF.636_B Figure 2. Results of cost-effectiveness analysis for each strategy and overall ICERs at 1, 3, 5, and 7 years for the base model and key structural sensitivity analyses. Results for strongly dominated strategies and negative ICER calculations are not reported. Reported ICERs are calculated from non-dominated strategies in order of increasing effectiveness. Abbreviations: ICER: Incremental cost-effectiveness ratio, QALY: Quality-adjusted life year, VDZ: Vedolizumab, ADA: Adalimumab, IFX: Infliximab, AZA: Azathioprine636_C Figure 3 No Caption available.