Public Health Implications and Economics of Combination Drugs: A Review of the Literature on Fluticasone propionate/salmeterol

BACKGROUND: Current asthma guidelines recommend the use of inhaled corticosteroids (ICS) as initial therapy for mild and moderate asthma. Long-acting β2-agonists (LABA) are recommended only for patients with severe asthma. In 2006, the FDA mandated the use of "black box" warning for all products containing LABA. This study sought to 1) perform an extensive and comprehensive literature review on asthma combination drugs; 2) to analyze the health and economic effects of those drugs; and 3) to draw some conclusions related with the public health implications and costs of asthma combination drugs.

DATA AND METHODS: An extensive and comprehensive review of the literature was performed to identify all peer reviewed studies published since 1970 containing information on asthma pharmaceutical products. The literature review was conducted in Medline, Crochrane Library, and the American Economic Association's electronic bibliography. The review included only studies conducted in the US. Clinical trials information was not included in this study.

RESULTS: Studies showed that 55.2-60% of patients filling claims for Fluticasone propionate/salmeterol (FPS) -a fixed-dose combination of ICS/LABA did not meet the current guidelines criteria for appropriate FPS use. The prescribing of FPS increased from 49.7 prescriptions fills per 100 asthma visits from the first year when FPS reached market to 119.9 on the third year. Most studies found that FPS results in incremental pharmacy costs and asthma related health costs, the additional expenditure of FPS prescriptions was estimated at $19,740 per 100 asthma visits in the third year after the introduction of FPS. The mean annualized incremental pharmacy cost of FPS per patient ranged from $177 to $320 compared with other asthma medications. The mean annualized incremental asthma related health cost of FPS per patient ranged from $28 to $402 compared with other asthma medications. The studies on asthma exacerbation had mixed results. One study predicted an additional 0.9 ED visits for additional 100 FPS prescriptions. Another study predicted a decrease of 1.2 annual adjusted rate of asthma-related ED visit for FPS, compared with FP alone. Most of the studies indicated similar hospitalization of FPS patients compared with other treatment groups.

CONCLUSIONS: Studies found that FPS was associated with higher cost and more asthma-related ED visits.