A systematic review and economic evaluation of the use of tumour necrosis factor-alpha (TNF-α) inhibitors, adalimumab and infliximab, for Crohn's disease

Crohn's disease (CD) is a severe, lifelong disease characterised by inflammation of the gastrointestinal mucosa. The impact on patients and society is high as ill health can be lifelong and can negatively affect patients' quality of life. Costs to the NHS are high, particularly for patients needing hospitalisation. Conventional treatment pathways are complex. More recently, a group of drugs called tumour necrosis factor (TNF) inhibitors (anti-TNF-α agents) have been evaluated for their effectiveness in CD. One of these, infliximab, is currently recommended by the National Institute for Health and Clinical Excellence (NICE; 2002) for patients with severe, active CD where patients are refractory to or intolerant of conventional treatment. To investigate whether there is evidence for greater clinical effectiveness or cost-effectiveness for either adalimumab or infliximab. Cochrane Library (Cochrane Central Register of Controlled Trials) 2007 Issue 2; MEDLINE (Ovid) 2000 to May/June 2007; MEDLINE In-Process & Other Non-Indexed Citations (Ovid) 4 June and 26 June 2007; EMBASE (Ovid) 2000 to May/June 2007. The European Medicines Agency, the US Food and Drug Administration and other relevant websites. Standard systematic review methods were used for study identification and selection, data extraction and quality assessment. Only randomised controlled trials (RCTs) comparing adalimumab or infliximab with standard treatment (placebo), RCTs comparing adalimumab with infliximab, or RCTs comparing different dosing regimens of either adalimumab or infliximab in adults and children with moderate-to-severe active CD intolerant or resistant to conventional treatment were eligible for inclusion. A systematic review of published studies on the cost and cost-effectiveness of adalimumab and infliximab was undertaken. The economic models of cost-effectiveness submitted by the manufacturers of both drugs were critically appraised and, where appropriate, rerun using parameter inputs based on the evidence identified by the authors of the technology asessment report. A de novo Markov state transition model was constructed to calculate the incremental cost-effectiveness ratio for adalimumab and infliximab therapy compared with standard care. Based on 11 trials, there was evidence from both induction and maintenance trials that both adalimumab and infliximab therapy were beneficial compared with placebo (standard care) for adults with moderate-to-severe CD and, for infliximab, for a