2111: Cost-effectiveness Analysis of Biosimilar Denosumab for the Treatment of Women with Post-menopausal Osteoporosis in the United States: A Risk Based Analysis

Background/Purpose: Post-menopausal osteoporosis (PMO) significantly increases the risk of fractures in women, necessitating effective treatment strategies. The introduction of biosimilar denosumab offers the opportunity to re-evaluate the value of common treatments for PMO. This study evaluates the cost-effectiveness of biosimilar denosumab versus bisphosphonates and no intervention across groups of women with PMO who have different underlying risks of fracture.

Methods: A previously developed Markov model was used. Subjects were stratified to 4 risk categories (i.e., from risk 1 [lowest risk] to risk 4 [highest risk]) based on occurrence of a prior vertebral fracture (yes/no) and T-score (‑2.5 or ≤ ‑2.5; Table 1). Model inputs, including baseline fracture risks, drug efficacy, administration costs, and utility values were estimated from publicly available data and literature. Biosimilar drug acquisition costs were assumed, based on trends of previously available biosimilars. The incremental costs, incremental quality-adjusted life-years (QALYs), and incremental cost-utility ratio (ICUR) were calculated from a US payer perspective.

Results: The use of biosimilar denosumab in women with PMO across risk categories 1, 2, 3, and 4 resulted in ICURs of $272,031, $105,129, $83,755, and $12,799, respectively, compared to alendronate. When compared to no intervention, biosimilar denosumab yielded ICURs of $213,660, $77,098, $60,976, and $954 for risk categories 1, 2, 3, and 4, respectively. This trend was consistent across all other comparators, demonstrating that as fracture risk increases, the ICURs for biosimilar denosumab compared to bisphosphonates and no intervention decrease (Table 2). Further decreases in biosimilar denosumab price led to improved cost-effectiveness and in some cases, domination.

Conclusion: Relative to common willingness-to-pay thresholds of $100,000 and $150,000, biosimilar denosumab is cost-effective for patients in risk categories 2, 3 and 4 when compared to bisphosphonates and no intervention in the treatment of PMO.