Cost-effectiveness of intravenous vedolizumab vs subcutaneous adalimumab for moderately to severely active ulcerative colitis

Background  

The efficacy of intravenous (IV) vedolizumab vs subcutaneous (SC) adalimumab for the treatment of moderately to severely active ulcerative colitis (UC) was assessed in the VARSITY clinical trial, which demonstrated for the first time in a head-to-head clinical trial setting the superiority of IV vedolizumab with respect to clinical remission and endoscopic improvement. Both therapies offer better clinical outcomes compared with immunomodulators and corticosteroids but are often more expensive than other pharmacologic treatment options. Thus, payers and decision makers face the task of leveraging finite resources for optimal health benefits, which can be aided by the use of cost-effectiveness models. 

Objective

To assess the cost-effectiveness of IV vedolizumab vs SC adalimumab from a US payer perspective using head-to-head data from the VARSITY trial. 

Methods  

A cohort decision tree was developed to estimate the costs and clinical outcomes associated with IV vedolizumab vs SC adalimumab to treat adults with moderately to severely active UC. Simulated cohorts began the model at treatment induction and continued to maintenance treatment with vedolizumab or adalimumab unless experiencing nonresponse or serious adverse drug reaction (ADR), in which case those patients transitioned to second-line treatment with tofacitinib, infliximab, or golimumab, where they could achieve response and/or remission or not. Those who still did not achieve response or remission or who had a serious ADR transitioned to a state of nonresponse for the remainder of the model or received surgery. The process was modeled for patients who were treatment naive and treatment experienced at baseline separately. Efficacy and safety inputs for vedolizumab and adalimumab were taken from the VARSITY trial, and corresponding inputs for other biologics were derived from a network meta-analysis. All clinical inputs were extrapolated over 2 years. Direct medical costs (expressed in 2019 US dollars) included those related to drug acquisition and administration, ADRs, routine monitoring, and additional treatment procedures. Outcomes were not discounted given the short time horizon. Univariate sensitivity and scenario analysis were applied to evaluate the robustness of the model to underlying parameter and structural uncertainty. 

Results 

Initial treatment with vedolizumab was associated with a higher remission rate at 2 years (73.5% vs 71.5%) and higher persistence (22.0% vs 14.4%) compared with adalimumab. Total direct medical costs were lower for the vedolizumab cohort ($100,022 vs $151,133), primarily driven by the lower annual drug acquisition cost of vedolizumab ($85,953 vs $137,492). When endoscopic improvement was used as the outcome measure, IV vedolizumab was also associated with higher endoscopic remission and lower overall costs. 

Conclusions

With better clinical outcomes and lower direct medical costs over a 2-year model horizon, vedolizumab IV was the dominant treatment strategy vs adalimumab SC in adults with moderately to severely active UC. Outcomes were driven primarily by the probability of major ADRs and induction response.