Cost-effectiveness of enzyme replacement therapy for type 1 Gaucher disease

OBJECTIVE: To evaluate the cost-effectiveness of enzyme replacement therapy (ERT) compared to standard medical care without ERT in the Dutch cohort of patients with type 1 Gaucher disease (GD I). DESIGN: Cost-effectiveness analysis was performed using a life-time state-transition model of the disease’s natural course. Transition probabilities, effectiveness data and costs were derived from retrospective data and prospective follow-up of the Dutch study cohort. SETTING: The tertiary referral center for Gaucher disease in the Netherlands. PARTICIPANTS: The Dutch cohort of patients with GD I. INTERVENTION: ERT versus standard medical care without ERT in symptomatic patients. MAIN OUTCOME MEASURES: Years free of end organ damage (YFEOD) (splenectomy, bone complication, malignancy, multiple complications), quality adjusted life years (QALY), and costs. RESULTS: Over an 85 year lifetime, an untreated GD I patient will generate 48.9 YFEOD and 55.86 QALYs. Starting ERT in a symptomatic patient increases the YFEOD by 12.8 years, while the number of QALYs gained increases by 6.27. The average yearly ERT medication costs range between €124,000 and €258,000 per patient. The lifetime costs of ERT starting in the symptomatic stage are €5,716,473 against €171,780 without ERT, a difference of €5,544,693. Consequently, the extra costs per additional YFEOD or per additional QALY are €434,416 and €884,994 respectively. After discounting effects by 1.5% and costs by 4% and under a reasonable scenario of ERT unit cost reduction by 25%, these incremental cost-effectiveness ratios could decrease to €149,857 and €324,812 respectively. DISCUSSION: ERT is a highly potential drug for GD I with substantial health gains. The conservatively estimated incremental cost-effectiveness ratios are substantially lower than for Pompe and Fabry disease. We suggest that the high effectiveness has contributed importantly to acceptance of reimbursement of ERT for GD I. The present study may further support discussions on acceptable price limits for ultra-orphan products.