Abstract
Using a Markov microsimulation model among hypothetical cohorts of community-dwelling older osteoporotic Japanese women with prior vertebral fracture over a lifetime horizon, we found that daily subcutaneous teriparatide for 2 years followed by weekly oral alendronate for 8 years was not cost-effective compared with alendronate monotherapy for 10 years. PURPOSE: Teriparatide has proven efficacy in reducing osteoporotic fractures, but with substantial cost. We examined the cost-effectiveness of sequential teriparatide/alendronate (i.e., daily subcutaneous teriparatide for 2 years followed by weekly oral alendronate for 8 years) compared with alendronate monotherapy for 10 years among community-dwelling older osteoporotic women with prior clinical or morphometric vertebral fracture in Japan. METHODS: Using a previously validated and updated Markov microsimulation model, we obtained incremental cost-effectiveness ratios (Japanese yen [¥] (or US dollars [$]) per quality-adjusted life year [QALY]) from the perspective of a single payer responsible for both public healthcare and long-term care. We assumed a lifetime horizon with a willingness-to-pay of ¥5million (or $47,500) per QALY in the base case. We modeled the cost of biosimilar teriparatide, which has been available since November 2019 in Japan, assuming the efficacy was the same as that of the brand version. RESULTS: In the base case, sequential teriparatide/alendronate was not cost-effective compared with alendronate monotherapy. In deterministic sensitivity analyses, sequential teriparatide/alendronate would become cost-effective with 85%, 50%, and 15% price discounts to teriparatide at ages 70, 75, and 80, respectively, compared to the current biosimilar cost. Otherwise, results were especially sensitive to changes that affected efficacy of teriparatide or alendronate. In probabilistic sensitivity analyses, the probabilities of sequential teriparatide/alendronate being cost-effective were 0%, 1%, and 37% at ages 70, 75, and 80, respectively. CONCLUSIONS: Among high-risk osteoporotic women in Japan, sequential teriparatide/alendronate was not cost-effective compared with alendronate monotherapy, even with the availability of biosimilar teriparatide.