P218 The cost-effectiveness of biological therapy cycles in the management of Crohn’s disease
K. Bolin*1, E. Louis2, E. Hertervig3
1Centre for Health Economics, Department of economics, University of Gothenburg, Gothenburg, Sweden, 2University Hospital CHU of Liège Belgium, Department of Gastroenterology, Liège, Belgium, 3Skane University Hospital, Lund, Department of Gastroenterology, Lund, Sweden
The objective of this study was to compare the cost-effectiveness of two de-escalation therapies with continued combination therapy using infliximab and an immunomodulator in patients with Crohn’s disease in clinical remission. The cost-effectiveness of different withdrawal strategies in which treatment is de-escalated in periods of remission is largely unknown. Published studies of related treatment strategies suggest that the cost-effectiveness is determined by the exact content of the treatment strategies compared and pharmaceutical prices. Thus, our objective was 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 immunomodulator therapy, compared with two different withdrawal strategies (1) withdrawal of the anti-TNFα therapy and (2) withdrawal of the immunomodulator therapy, respectively, and to examine the significance of pharmaceutical prices for the estimated cost effectiveness.
A decision-tree simulation model (Markov type) was constructed mimicking three treatment arms: (1) continued combination therapy with infliximab and immunomodulator, (2) withdrawal of infliximab, or (3) withdrawal of the immunomodulator. 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.
Combination therapy was less costly and more efficient (produced better health outcomes) than the withdrawal of the immunomodulator, 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.
Combination therapy using a combination of anti-TNFα (infliximab) and immunomodulator is cost effective in the treatment of Crohn’s disease compared with treatment cycles in which the immunomodulator is withdrawn. Combination treatment is not cost effective compared with treatment cycles in which infliximab is withdrawn, at current pharmaceutical prices. This conclusion is likely to be altered as the price of infliximab continues to decrease.