Cost-effectiveness of adalimumab for rheumatoid arthritis in Germany

C. Gissel, G. Götz, H. Repp

In Germany, the clinical use of TNF-α inhibitors in the therapy of rheumatoid arthritis (RA) grew from 2 % of treated patients in 2000 to 20 % in 2008. In 2012, adalimumab was the bestselling drug in the statutory health insurance system with net expenditure of € 581 mio. We aim to analyze the cost-effectiveness of adalimumab for the treatment of RA in Germany. We set up an individual patient sampling lifetime model to simulate 10,000 hypothetical patients. The patients' functional status improves according to American College of Rheumatology response criteria. In each 6‑month cycle, treatment might be discontinued due to loss of efficacy or adverse events. In the base case, patients gain 7.07 quality-adjusted life years (QALYs) with conventional synthetic therapy and 9.92 QALYs if adalimumab combination therapy is added to the treatment algorithm. The incremental cost-utility ratio (ICUR) is € 24,492 based on German list prices. After deducting mandatory rebates and taxes, the ICUR is € 17,277, comparing favorably to analyses in other countries. Adalimumab combination therapy lowers indirect costs from € 162,698 to € 134,363. The ICUR based on total costs is € 14,550 (€ 7,335 after deducting taxes and rebates). Sensitivity analysis shows that adalimumab combination therapy becomes a dominant treatment option for younger baseline populations, i. e. adalimumab is both more effective and less expensive for baseline age 30 due to savings in indirect costs. Our complex probabilistic model shows that estimation of cost-effectiveness for RA relies on the incorporation of indirect costs and a sufficiently long simulation horizon to capture the complete range of possible outcomes and the associated long-term benefits of biological treatment.