Candidate for the Lee B. Lusted Student Prize Competition
Purpose: Omalizumab, a recombinant humanized monoclonal anti-IgE antibody, reduces risk of exacerbations and improves health-related quality of life (HRQoL) among patients with moderate to severe persistent asthma. Several economic evaluations of omalizumab have been reported previously. Our objective was to evaluate cost-effectiveness of omalizumab, using results of a randomized controlled trial which enrolled Asian population for the first time and was conducted in Japan.
Method: We developed a Marcov model comparing omalizumab plus standard therapy with standard therapy alone, on the basis of efficacy data from the randomized placebo-controlled double-blind trial and cost data of Japan. Our model had a lifetime horizon in which five-year omalizumab plus standard therapy was followed by standard therapy alone. The study cohort matched the clinical trial population with an average age of 50 and 50% men. Omalizumab provides different benefits for patients with persistent asthma, although no predictive factor for response has been found. Non-responders who represented little effect of omalizumab reverted back to standard therapy after 16-week omalizumab therapy. We assumed that patients could transition every week among symptom-free state, day-to-day state, and exacerbation state, and that patients in asthma-related hospitalization state were at risk of dying from asthma exacerbation. We derived preference-based utility values from another study examining relationship between asthma control level and HRQoL because the clinical trial in Japan failed to measure HRQoL convertible into utilities. Costs from a societal perspective included estimates for drugs, medical resource uses, and lost productivity.
Result: The mean lifetime discounted costs and quality-adjusted life years (QALYs) were $118,000 and 16.097 for omalizumab plus standard therapy, and $47,000 and 16.003 for standard therapy alone. The incremental cost-effectiveness ratio (ICER) was $751,000/QALY. One-way sensitivity analyses indicated that the results were sensitive to asthma-related mortality, exacerbation rates, symptom-free rates, and omalizumab price.
Conclusion: The result of the base case analysis suggested that omalizumab was not cost-effective given a willingness to pay of $54,000 in Japan. However, omalizumab possesses a unique mechanism and is required for the treatment of persistent asthma. The cost-effectiveness of omalizumab would be improved if the price of omalizumab is cut down and omalizumab therapy is confined to patients with higher asthma mortality or exacerbation risk.