Canadian cost-utility analysis of initiation and maintenance treatment with anti-TNF-α drugs for refractory Crohn's disease

Abstract

Objectives: Crohn's disease (CD) is a chronic inflammatory disease of the gastrointestinal tract. Symptoms include but are not limited to abdominal pain, nausea, emesis, and diarrhea. Anti-TNF-α drugs are increasingly being used in patients with CD who have inadequate response to conventional therapy. However, these medications are quite expensive. The objective of this study is to evaluate the cost-utility of two anti-TNF-α drugs (infliximab, adalimumab) for refractory CD.

Methods: A Markov model was used to estimate the costs and QALYs of three treatments (usual care, infliximab, adalimumab) over a 5 year time horizon. After initial treatment, patients achieve remission, achieve treatment response or remain in the drug refractory health state. Patients who achieve remission or treatment response are at risk of relapse each 3 month model cycle. Patients in the drug refractory health state either remain in the health state or have surgery in each cycle. Different costs and utility values were assigned to the various model health states. Model input parameters including initial response rates, relapse rates, utility values were derived from published literature.

Results: Usual care had both the lowest expected costs ($17,017) and QALYs (2.555), while infliximab had both the highest expected costs ($54,084) and QALYs (2.721). The incremental cost per QALY moving from usual care to adalimumab and from adalimumab to infliximab was estimated to be to be $193,305 and $451,165, respectively.

Conclusions: Based on common willingness to pay thresholds, ant-TNF-α drugs would not be perceived as a cost effective treatment for refractory CD.