Mirabegron or tolterodine for the treatment of overactive bladder in Japan: Which drug is more cost-effective as the first-line treatment?

Objectives: To assess the cost-effectiveness of mirabegron 50 mg relative to tolterodine extended release 4 mg for the treatment of overactive bladder if used as the first-line treatment in Japan.
Methods: A Markov model was developed to simulate the cost-effectiveness of the mirabegron first-line treatment (and tolterodine second-line) versus tolterodine first-line treatment (and mirabegron second-line) taken for 5 years from the randomized European-Australian study (SCORPIO trial) and single technology appraisal assessment report by the National Institute for Health and Care Excellence. The incremental cost-effectiveness ratio was calculated with utility value by quality-adjusted life year with cost using the medical fee and the drug price tariff in 2016. For the study of transition of treatment status, our analytical model was established. The transition probabilities of severity states were calculated based on the probabilities for the mean numbers of incontinence episodes/day and micturition episodes/day in mirabegron-treated and tolterodine-treated patients in the single technology appraisal assessment report.
Results: The 5-year expected effect per patient was 3.860 quality-adjusted life years for first-line mirabegron and 3.839 quality-adjusted life years for first-line tolterodine. The 5-year expected cost per patient was ¥526 191 for first-line mirabegron, and ¥472 390 for first-line tolterodine. The incremental cost-effectiveness ratio was ¥2 565 927/quality-adjusted life year. This value was below the willingness-to-pay threshold of ¥5 million/quality-adjusted life year. In more severe states, the incremental cost-effectiveness ratio exceeded ¥5 million.
Conclusions: First-line mirabegron appears to be more cost-effective than first-line tolterodine. In patients with severe symptoms, first-line mirabegron is not economically preferable.
(© 2018 The Japanese Urological Association.)