The cost-effectiveness of onabotulinumtoxinA for the prophylaxis of headache in adults with chronic migraine in the UK.

Background: Although chronic migraine is associated with substantial disability and costs, few treatments have been shown to be effective. OnabotulinumtoxinA (Botox, Allergan Inc., Irvine, CA) is the first treatment to be licensed in the UK for the prophylaxis of headaches in adults with chronic migraine. This study aims to evaluate the cost-effectiveness of onabotulinumtoxinA in this indication in the UK.

Methods: A state-transition (Markov) model was developed comparing onabotulinumtoxinA to placebo. Efficacy data and utility values were taken from the pooled Phase III REsearch Evaluating Migraine Prophylaxis Therapy (PREEMPT) clinical trials program (n = 1384). Estimates of resource utilisation were taken from the International Burden of Migraine Study (IBMS), and stopping rules were informed by published medical guidelines and clinical data. This study estimated 2-year discounted costs and quality-adjusted life years (QALYs) from the UK National Health Service perspective.

Results: At 2 years, treatment with onabotulinumtoxinA was associated with an increase in costs of £1367 and an increase in QALYs of 0.1 compared to placebo, resulting in an incremental cost-effectiveness ratio (ICER) of £15,028. Treatment with onabotulinumtoxinA reduced headache days by an estimated 38 days per year at a cost of £18 per headache day avoided. Sensitivity analysis showed that utility values had the greatest influence on model results. The ICER remained cost-effective at a willingness to pay threshold of £20,000-£30,000/QALY in the majority of scenario analyses as well as in probabilistic sensitivity analysis, where onabotulinumtoxinA was cost-effective on 96% of occasions at a threshold of £20,000/QALY and 98% of occasions at £30,000/QALY.

Conclusion: OnabotulinumtoxinA has been shown to reduce the frequency of headaches in patients with chronic migraine and can be considered a cost-effective use of resources in the UK National Health Service. The uncertainties in the model relate to the extrapolation of clinical data beyond the 56-week trial.