Abstract
Background
VARSITY (NCT02497469) is the first head-to-head trial comparing two biologic therapies, intravenous vedolizumab (VDZ IV) and subcutaneous adalimumab (ADA), in adults with moderately to severely active ulcerative colitis (UC). We evaluated the cost-effectiveness of VDZ IV vs. ADA from a US payor perspective using efficacy data from VARSITY.
Methods
We used a cohort decision tree model with a time horizon up to 2 years. Simulated cohorts included patients with or without prior biologic therapy who initiated treatment with VDZ IV (300 mg in weeks 0, 2, and 6) or ADA (day 1: 160 mg; day 15: 80 mg) for a 6-week induction period. Initial responders proceeded to maintenance treatment with VDZ IV (300 mg every 8 weeks) or ADA (40 mg every 2 weeks); maintenance phase remitters continued treatment for 2 years. Patients with inadequate response to induction or a serious adverse drug reaction (ADR) switched to treatment with biologics (tofacitinib, infliximab, or golimumab). Patients who were intolerant to biologics received corticosteroids with or without curative surgery. The relative effectiveness of VDZ IV vs. ADA was derived from network meta-analyses of published randomised controlled trials. Model outcomes included total direct medical costs associated with drug acquisition, administration, routine monitoring, toxicity management, ADRs, and cost per remission achieved. Costs (eg, drug, monitoring, healthcare resource utilisation, administration) were expressed in 2019 US$.
Results
Based on our model, VDZ IV was associated with greater induction response (52.92% vs. 45.07%) and remission 2 (21.95% vs. 14.36%) rates at year 2 compared with ADA. Total direct medical costs were $90,673 for VDZ IV and $137,007 for ADA. After 2 years of treatment, more patients in the VDZ IV cohort were in remission and for lower costs compared with ADA.
Conclusion
The clinical foundation of this model is predicated primarily on head-to-head evidence from the Phase 3 VARSITY trial. This allowed us to extrapolate clinical outcomes out to 2 years and estimate direct medical costs over that timeframe. These modelled outcomes indicate that over a 2-year time horizon adults with moderately to severely active UC are expected to achieve better clinical outcomes and incur lower direct medical costs vs. ADA.
Cost-effectiveness of intravenous vedolizumab vs subcutaneous adalimumab for moderately to severely active ulcerative colitis
