Maxime Verhoeven

140 Chapter 7 Figure 3 Cost effectiveness acceptability curve for the TCZ-based initiation treatment strategy groups versus the MTX initiation strategy group over 5 years, using the so- cietal perspective (human capital approach). TCZ+MTX= initiation of tocilizumab + methotrexate strategy group; TCZ= initiation of tocilizumab + placebo- methotrexate strategy group; MTX= initiation of methotrexate + placebo-tocilizumab strategy group. Example: Using a willingness to pay of €50,000, the probability that TCZ+MTX or TCZ is more cost-effective compared to MTX is 0 or 20%, respectively. Sensitivity and scenario analyses Results of the sensitivity/scenario analyses are shown in Table 3. Overall results confirmed that the probability that TCZ strategies are cost-effective is low. The exception may be if a cost reduction of 30% for subcutaneously administrated TCZ is assumed. In this case the cost savings are considerable and may compensate for the limited QALY loss for TCZ compared to those of MTX (taking a societal perspective and using a human capital approach). TCZ is found to be dominant in 25% of the bootstrap samples, and in 49% less expensive, but also less effective in this case. Assuming a QALY gain of 0.05, the average QALY difference between TCZ and MTX become positive, and TCZ is dominated in 15% of all bootstrap samples, and in 11% TCZ was found less expensive, but also less effective. In the subgroup of patients with a DAS28>5.1 at start of treatment, TCZ is found to be dominant in 21% of the bootstrap samples, and in 24% less expensive, but still somewhat less effective (mean difference in QALY -0.01). Outcomes based on undiscounted values are shown in Supplementary Table 6. Supplementary Figure 3 and 4 illustrate the CEACs at different willingness to pay, for our base case and all sensitivity analyses.