The cost-effectiveness of biological therapy cycles in the management of Crohn’s disease

Objectives: to examine the cost-effectiveness of continued treatment for patients with moderate-severe Crohn’s disease in clinical remission, with a combination of anti-TNFα (infliximab) and immunosuppressant therapy compared to two different withdrawal strategies (1) withdrawal of the anti-TNFα therapy, and (2) withdrawal of the immunosuppressant therapy, respectively. Material and methods: A decision-tree model (Markov type) was constructed mimicking three treatment arms: (1) continued combination therapy with infliximab and antimetabolites, (2) withdrawal of infliximab, or (3) withdrawal of the immunosuppressant. Relapses in each arm are managed with treatment intensification. State dependent relapse risks, remission probabilities and quality of life weights were collected from previous published studies. Results: Combination therapy was less costly and more efficient than the withdrawal of the immunosuppressant, and more costly and more efficient than withdrawal of infliximab. The incremental cost-effectiveness ratio for the combination therapy compared with withdrawal of infliximab was estimated at SEK 755 449 per additional QALY. This is well above the informal willingness-to-pay threshold in Sweden (500 000 SEK/QALY). The estimated cost-effectiveness of the combination therapy was found highly sensitive to the unit cost of infliximab; at a 36% lower unit cost of infliximab, the combination treatment would become cost-effective. The qualitative content of these results were quite robust to changes in the clinical effectiveness and the quality-of-life figures adopted in the calculations. The qualitative content of these results were quite robust to changes in the clinical effectiveness and quality-of-life values. Conclusions: Combination therapy using a combination of anti-TNFα (infliximab) and immunosuppressant is cost effective in the treatment of Crohn’s disease compared to treatment cycles in which the immunosuppressant is withdrawn. Combination treatment is not cost effective compared to treatment cycles in which infliximab is withdrawn, at current pharmaceutical prices.