Análise econômica do denosumabe e dos bisfosfonatos no tratamento de pacientes com metástase óssea

Abstract

Introduction: Bone metastases are prevalent among patients with advanced cancer and may result in significant decrease in quality of life. Its treatment consists of pain alleviation and prevention of Skeletal Related Events (SRE), highly debilitating complications with multidimensional impact. Bisphosphonates and denosumab are the treatment of choice to prevent SRE. Both are high cost medications of chronic use, which requires cost effectiveness analyses to support decision making in resource allocation. Objectives: To conduct an economic analysis of bone-targeted agents for the treatment of bone metastases secondary to solid tumors. Methods: A Health Technology Assessment (HTA) with Cost-Effectiveness Analysis (CEA) and Budget Impact Analysis (BIA) was performed from the Brazilian Unified Healthcare System, over a 2-year time horizon. Data were collected from different sources and included national databases for different categories of costs, and scientific articles for effectiveness, measured by the proportion of SRE-free patients. The CEA was based on two Markov models: For patients with breast cancer, in which the treatment was based on denosumab, zoledronic acid or pamidronate; and for Other Solid Tumors (OST), based on the use of denosumab and zoledronic acid. In these models, four health states (with/without SRE, new SRE, and death), and their transition probabilities were considered. Results were expressed by means of Incremental Cost-Effectiveness Ratios (ICER), and the uncertainties were tested in deterministic and probabilistic sensitivity analyses. A BIA in five years was conducted considering different scenarios. Results: In the Markov model for breast cancer, pamidronate was the cost-effective strategy. In the zoledronic acid/pamidronate and denosumab/pamidronate comparisons, ICERs of R$ 5,935.70 and R$ 17,929.09 per SRE avoided were observed. In the OST model, zoledronic acid was the cost-effective strategy, and the ICER of denosumab compared with zoledronic acid was R$ 26,061.44 per SRE avoided. Sensitivity analysis confirmed the robustness of the model, as results remained unchanged. In the BIA, regardless of tumor type, the least costly scenario in five years was the one in which all patients received zoledronic acid. Conclusion:Considering the Brazilian healthcare setting, the CEA showed that pamidronate for breast cancer and zoledronic acid for OST were the cost-effective strategies.Denosumab coverage would result in substantial increase in treatment costs.However, in the decision-making process, factors beyond effectiveness, safety and costs should be considered, for example, acceptability, patients values and preferences, feasibility and equity.