OBJECTIVES

Specialty medications are costly and the cost-sharing placed on patients has been steadily increasing in the US. Ivacaftor, a specialty medication for the treatment of cystic fibrosis (CF), is one of the most expensive medications. However, little is known about the cost burden born by patients and how this affects Ivacaftor demand.

METHODS

An ecological study was designed to assess trends in out-of-pocket costs, average wholesale price (AWP), and relative change in utilization of Ivacaftor over time on a monthly basis. Patients with a diagnosis for CF (ICD-9-CM: 277.02) were selected from the Marketscan commercial claims database between 1/1/2012-12/31/2014. Out-of-pocket costs were calculated as a summation of the deductible, copay as well as the coinsurance. Proportional changes in subsequent months were used to express the change in demand for patients in the previous month. Segmented regression analysis was used to conduct a time series analysis that assessed price elasticity.

RESULTS

The study sample comprised 277 patients with evidence of CF and a claim for Ivacaftor. The average wholesale price stayed relatively stable at $29,336 in 2012, $30,715 in 2013 and $30,723 in 2014. However, the average out-of-pocket costs started at $194 and increased from $137 in 2013 to $174 in 2014. The average Ivacaftor utilization increased from 67% in 2012-2013 to 70% in 2014. Demand for Ivacaftor was negatively associated (-3.1%) with the out-of-pocket costs burden on the patient (p=0.0003).

CONCLUSIONS

Despite the AWP of Ivacaftor being consistent over time, the out-of-pocket cost to patients increased in 2014, demonstrating a shift in cost-sharing burden to patients. Compared to general medicine, which has a price elasticity of -20.9%, this study has an elasticity of -3.1% showing that patients are more price inelastic with Ivacaftor.