ND4 - Cost-Utility Analysis Comparing Abobotulinumtoxina with Onabotulinumtoxina for the Treatment of Pediatric Lower Limb Spasticity

Abstract

Pediatric lower limb (PLL) spasticity is a disabling condition that commonly affects patients with cerebral palsy. Toxins can effectively inhibit contraction of the injected muscle to manage spasticity and augment rehabilitation. In Canada, onabotulinumtoxinA was the only toxin available for the treatment of lower limb spasticity among children (indicated for equinus foot but used off-label for PLL generally). A newer therapy, abobotulinumtoxinA, has recently been approved for PLL, with demonstrated tolerability and efficacy. The objective of this study was to assess the value of abobotulinumtoxinA vs. onabotulinumtoxinA for the treatment of PLL spasticity from a Canadian public-payer perspective. An economic evaluation was performed using a Markov cohort model with 12-week cycles corresponding to toxin dosing schedules over a 12-year horizon. Health states were based on response status on the goal attainment scale (GAS), with GAS outcomes informed by a network meta-analysis of onabotulinumtoxinA and abobotulinumtoxinA clinical trials. Utilities were obtained from clinical trial data and stratified by GAS response. Health care resource use and costs were based on a survey of Canadian clinical experts and costs from an Ontario public-payer perspective. Costs and outcomes were discounted 1.5% per year. A 10,000-iteration probabilistic analysis (PA) was conducted, as well as scenario analyses considering variations to relevant parameters. In the base case, abobotulinumtoxinA was associated with 9.08 quality-adjusted life years (QALYs), while onabotulinumtoxinA was associated with 8.98 QALYs. Incremental costs were an additional $765 for abobotulinumtoxinA, for an incremental cost-utility ratio of $9,321 per QALY across PA iterations. Across scenario analyses, abobotulinumtoxinA tended to remain cost-effective, or in some cases dominated onabotulinumtoxinA. Canadian children with lower limb spasticity previously had only onabotulinumtoxinA as an available option for toxin therapy. This analysis shows that abobotulinumtoxinA is a cost-effective alternative that may be associated with increased quality of life.