Economic value of zoledronic acid versus placebo in the treatment of skeletal metastases in patients with lung cancer: The case of the United Kingdom (UK)

Abstract

6617 Objectives: Zoledronic acid (ZA) reduces the risk of skeletal-related events (SREs) in lung cancer patients with bone metastases and may improve survival among those patients with high levels of bone metabolism. This analysis assessed, from the UK National Health Service's perspective, the economic impact of ZA therapy in patients with bone metastases secondary to lung cancer. Methods: A literature-based decision analytic model was developed to compare the direct costs and quality adjusted life years (QALY) experienced by lung cancer patients with bone metastases receiving placebo or ZA. Survival, SRE incidence, and number of infusions administered were obtained from a randomized clinical trial comparing 4 mg ZA with placebo. Drug acquisition and administration costs and SRE costs were estimated using published sources and national fee schedules (i.e., NHS reference costs, British National Formulary, Personal Social Services Research Unit reference costs). The impact of SREs on quality of life was estimated using the literature. Consistent with previous economic analyses of bisphosphonates in cancers (e.g., Hillner et al, 2000), patients avoiding SREs were assumed to experience quality of life improvements for 1 month. Results: The average remaining life expectancy was conservatively assumed equal in both groups and was 8.50 months (median, 5.89 months). During those months, patients receiving placebo were projected to experience 2.07 SREs on average compared to 1.32 SREs among ZA patients. QALYs were estimated at 0.3523 per patient (pp) and 0.3350 pp in the ZA and placebo groups, respectively. ZA drug-related costs were estimated at £1,473 pp, based on 5.87 infusions pp and a cost of £251.01 per infusion. The use of ZA was associated with a reduction of £1,562 pp in SRE costs. Overall, ZA saved costs and increased QALYs compared to no therapy, by £89 pp and 0.0173 QALYs pp, respectively. In sensitivity analyses, ZA cost £25,000 or less per QALY under a wide range of assumptions. Conclusions: The use of ZA leads to fewer SREs, better estimated quality of life, and lower costs relative to placebo in UK lung cancer patients with bone metastases. The use of ZA in this population therefore appears highly cost effective. No significant financial relationships to disclose.