Cost-Effectiveness Analysis of Omalizumab for the Treatment of Severe Asthma in Japan and the Value of Responder Prediction Methods Based on a Multinational Trial

Objectives: Omalizumab improves health outcomes for patients with severe asthma. The purpose of this study was to conduct a cost-utility analysis of omalizumab from a societal perspective by using the results from a randomized controlled trial in Japan, and explore the efficient use of omalizumab. Methods: We developed a Markov model to compare omalizumab add-on therapy with standard therapy. Patients transitioned between symptom-free, day-to-day, and exacerbation states. Our model had a lifetime horizon in which 5-year omalizumab add-on therapy was followed by standard therapy. Preference-based utilities were extracted from another study. We estimated the expected value of perfect information for patients’ response to omalizumab. Results: In the base case, incremental cost-effectiveness ratio (ICER) for omalizumab add-on therapy was US $755,200 (95% credible interval [CI] $614,200–$1,298,500) per quality-adjusted life-year gained, compared with standard therapy alone. One-way sensitivity analyses indicated that the results were sensitive to asthma-related mortality, exacerbation risk, and omalizumab cost. The ICER for a responder subgroup was 22% lower than that in the base case. Individual and population expected value of perfect informations for the response were $4100 (95% CI $2500–$6000) and $28 million (95% CI $17 million–$42 million) per year, respectively. Conclusions: With a willingness-to-pay of $45,000 per quality-adjusted life-year, omalizumab was not cost-effective in Japan. Confining omalizumab therapy to previously predicted responders, however, may be a reasonable strategy to reduce the ICER, as the costeffectiveness was observed to improve for these patients. Further studies should be conducted to explore responder prediction methods. Decreasing the price of omalizumab would improve cost-effectiveness.