J W Hay1, E D Robin. 1. Hoover Institution, Stanford University, CA 94305-6010.
Abstract
BACKGROUND: Alpha 1-antitrypsin (AAT) replacement therapy is an expensive intervention ($20,000-$30,000 per patient annually) which may slow or arrest the progression of chronic obstructive pulmonary disease (COPD) in AAT-deficient patients. While FDA-approved, therapy efficacy is unknown. The costs and benefits of AAT replacement therapy were evaluated for patients with congenital COPD. METHODS: Epidemiological and disease cost data were taken from published sources. A discrete-time model of disease stage probability transition was developed to calculate the present-value expected cost of disease treatment, under a range of possible therapy efficacy and other parameter values. RESULTS: At an efficacy of 70 percent, the cost per life year saved with AAT replacement therapy would be between $28,000 and $72,000 (1990 US dollars), depending on patient age, sex, and smoking status. At 30 percent efficacy, the cost per life year saved range would be between $50,000 and $128,000. A controlled efficacy study would cost $53 million or less, if the true efficacy were 50 percent or better. CONCLUSIONS: With efficacy of 30 percent or higher, therapy cost-effectiveness would be comparable to other widely used medical interventions. The economic assessment methodology was used to evaluate both the therapeutic innovation and the value of additional clinical research.
BACKGROUND:Alpha 1-antitrypsin (AAT) replacement therapy is an expensive intervention ($20,000-$30,000 per patient annually) which may slow or arrest the progression of chronic obstructive pulmonary disease (COPD) in AAT-deficientpatients. While FDA-approved, therapy efficacy is unknown. The costs and benefits of AAT replacement therapy were evaluated for patients with congenital COPD. METHODS: Epidemiological and disease cost data were taken from published sources. A discrete-time model of disease stage probability transition was developed to calculate the present-value expected cost of disease treatment, under a range of possible therapy efficacy and other parameter values. RESULTS: At an efficacy of 70 percent, the cost per life year saved with AAT replacement therapy would be between $28,000 and $72,000 (1990 US dollars), depending on patient age, sex, and smoking status. At 30 percent efficacy, the cost per life year saved range would be between $50,000 and $128,000. A controlled efficacy study would cost $53 million or less, if the true efficacy were 50 percent or better. CONCLUSIONS: With efficacy of 30 percent or higher, therapy cost-effectiveness would be comparable to other widely used medical interventions. The economic assessment methodology was used to evaluate both the therapeutic innovation and the value of additional clinical research.