Cost-Effectiveness Analysis of PCSK9 Inhibitors in Patients with Atherosclerotic Cardiovascular Disease Without Prior Ischemic Events in Italy

BACKGROUND AND OBJECTIVE: Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) are an effective class of lipid-lowering drugs in patients with primary hypercholesterolemia or mixed dyslipidemia. New evidence supported the early use of PCSK9i in patients with atherosclerotic cardiovascular disease without prior ischemic events and not achieving the low-density lipoprotein-cholesterol targets despite being treated with other lipid-lowering therapies. The aim of the study is to evaluate the cost effectiveness of PCSK9i monoclonal antibodies (mAbs) as an add-on treatment in this population over the lifetime horizon from the Italian National Health Service perspective. METHODS: A Markov model with a 1-year cycle length was developed to evaluate the incremental cost and effectiveness of maximum tolerated statins plus ezetimibe (MTS+E) with versus without PCSK9i mAbs in high-risk patients with atherosclerotic cardiovascular disease without prior ischemic events. Baseline cardiovascular risk and relative cardiovascular risk reduction attributed to PCSK9i mAbs for major adverse cardiovascular events (i.e., acute coronary syndrome, ischemic stroke, and all-cause mortality) were based on analysis using the US Optum Research database. Costs of drugs and management of cardiovascular events were considered in the analysis. Utility values were sourced from the existing literature. Both deterministic and probabilistic sensitivity analyses were conducted to assess the robustness of the result. RESULTS: The simulated cohort's mean age was 68 years and mean baseline low-density lipoprotein-cholesterol level was 129.7 mg/dL, with female individuals and diabetes mellitus accounting for 50.1% and 34.8%, respectively. The incremental cost and quality-adjusted life-year (QALY) gained of MTS+E with added PCSK9i mAbs versus without PCSK9i mAbs were €61,334 and 2.42 QALY, equivalent to €25,350 per QALY gained. At a willingness-to-pay threshold of €33,000 per QALY gained, MTS+E plus PCSK9i mAbs had about 65% probability of being cost effective versus MTS+E alone. CONCLUSIONS: The results demonstrated that PCSK9i mAbs as an add-on therapy to MTS+E are likely to be cost effective when compared with MTS+E alone in high-risk patients with atherosclerotic cardiovascular disease without prior ischemic events from the Italian National Health Service perspective.