Preferences for Biologic Treatments: A Discrete Choice Experiment Survey of Canadians with Severe Asthma

Purpose: The safety and efficacy of biologics for severe asthma have been demonstrated in clinical trials, and subsequent economic evaluations have established their value from a population perspective. Insight into patient preferences for attributes of biologic treatments can inform treatment-related decisions and promote adherence. However, such data are limited in Canada, and no willingness-to-pay (WTP) data exists. This study aimed to quantify the strength of preferences of those with severe asthma for attributes of biologic treatments. Patients and Methods: Canadians with severe asthma completed a discrete choice experiment (DCE) consisting of 15 choice tasks and six biologic treatment attributes (improving daily activities, controlling other health conditions, frequency of administration, monthly out-of-pocket costs, reducing attack frequency, and reducing rescue inhaler use). Odds ratios (OR) and 95% confidence intervals (CI), and WTP (the marginal rate of substitution of attributes for money) were estimated using a conditional logistic regression. Results: Ninety-seven eligible and unique participants completed the survey (70.1% female; mean [SD] age: 54.6 [14.4]; 48.4% ever used biologics). A dramatic (vs slight) improvement in daily activities increased the odds of a biologic being preferred by 78% (OR 1.78, 95% CI 1.48, 2.14), and a $100 increase in monthly out-of-pocket costs decreased the odds by 64% (OR 0.64, 95% CI 0.61, 0.67). On average, WTP was an extra $129 CAD in monthly out-of-pocket costs for a dramatic (vs slight) improvement in daily activities. WTP for a hypothetical biologic treatment was an extra $430 CAD in monthly out-of-pocket costs. Conclusion: Canadians with severe asthma prefer biologic treatments that dramatically improve daily activities and have lower out-of-pocket costs. This DCE is the first to include a cost attribute and estimate WTP. These data can help inform decision-making when considering access to new biologic treatments for severe asthma and clinicians when helping patients select treatments for severe asthma.