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 microsimulation 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 (€, 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 ¬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 ¬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 ¬38 514, h22 220 and ¬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 ¬37 167, ¬19 718 and h19 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.