Cost Effectiveness of Denosumab Compared with Oral Bisphosphonates in the Treatment of Post-Menopausal Osteoporotic Women in Belgium

Background: Denosumab has recently been shown to be well tolerated, to increase bone mineral density (BMD) and to significantly reduce the risk of hip, vertebral and non-vertebral fractures in the FREEDOM (Fracture REduction Evaluation of Denosumab in Osteoporosis every 6 Months) trial. It is becoming increasingly important to evaluate not only the therapeutic value of a new drug but also the cost effectiveness compared with the most relevant treatment alternatives. Objective: The objective of this study was to estimate the cost effectiveness of denosumab compared with oral bisphosphonates (branded and generic drugs) in the treatment of post-menopausal osteoporotic women in Belgium. Methods: Cost effectiveness of 3 years of treatment with denosumab was compared with branded risedronate and branded and generic alendronate using an updated version of a previously validated Markov microsiraulation model. The model was populated with relevant cost, adherence and epidemiological data for Belgium from a payer perspective and the results were presented as costs per QALY gained ((sic), year 2009 values). Analyses were performed in populations (aged >= 60 years) in which osteoporosis medications are currently reimbursed in many European countries, i.e. those with BMD T-score of -2.5 or less or prevalent vertebral fracture. Patients receiving denosumab were assumed to have a 46% lower risk of discontinuation than those receiving oral bisphosphonates, and the effect of denosumab after treatment cessation was assumed to decline linearly to zero over a maximum of 1 year. Results: Denosumab was cost effective compared with all other therapies, assuming a willingness to pay of (sic)40 000 per QALY gained. In particular, denosumab was found to be cost effective compared with branded alendronate and risedronate at a threshold value of (sic)30 000 per QALY and denosumab was dominant (i.e. lower cost and greater effectiveness) compared with risedronate from the age of 70 years in women with a T-score of -2.5 or less and no prior fractures. The cost effectiveness of denosumab compared with generic alendronate was estimated at (sic)38 514, (sic)22 220 and (sic)27 862 per QALY for women aged 60, 70 and 80 years, respectively, with T-scores of -2.5 or less. The equivalent values were (sic)37 167, (sic)19 718 and (sic)19 638 per QALY for women with prevalent vertebral fractures. Conclusion: This study suggests, on the basis of currently available data, that denosumab is a cost-effective strategy compared with oral bisphosphonates (including generic alendronate) for the treatment of post-menopausal osteoporotic women, aged >= 60 years in Belgium. Denosumab therefore appears to have the potential to become a first-line treatment for post-menopausal women with osteoporosis. However, further studies would be required to evaluate the long-term safety and adherence of denosumab in real-world clinical practice as well as head-to-head effectiveness compared with oral bisphosphonates.