the optimal strategy was 1.0. The probability of strategy B
being optimal was 0.5 when the WTP approximated
$400,000/QALY. The probability of strategy C being optimal
was very low despite the wide range of WTP values.
Discussion
Increasing health care costs with limited resources is highlighting
the importance of economic issues in addition to
efficacy and safety. In Canada, economic evaluation has
been incorporated into the decision making process since
1994. Facing increasing volume of reimbursement
requests for anti-TNF-α drugs, the Canadian decision
makers have to evaluate these drugs in terms of incremental
cost-utility over the existing treatment options.
Infliximab has demonstrated clinical efficacy in patients
with active UC in randomized clinical trials[10,16]. However,
the costs of infliximab were significantly higher than
the costs of 'usual care'. The ICUR was not favorable to infliximab
based on the existing evidence, according to commonly
accepted willingness to pay threshold (e.g., US
$50,000).
This study demonstrated that increasing the dose of infliximab
to 10 mg/kg in those patients who had a loss of
response to 5 mg/kg infliximab was not cost-effective
compared to either 'usual care' or switching to adalimumab.
Clinical experts also suggested a strategy of reducing
the dose interval for non-responders. However, this strategy
was not considered in the model due to lack of clinical
evidence.