A recent review of 19 articles published between 1995-2014 found evidence that reductions in specialty drug utilization were associated with higher cost sharing, with the effects varying by the type of disease and outcome of the drug in use. 

The study, conducted by University of Pennsylvania researchers and published in the American Journal of Managed Care, suggested further examination of specialty drug cost-sharing policies, as well as interim policies to protect patients against aggressive cost-sharing policies.

The number of patients using specialty drugs is relatively small, with estimates somewhere between 1 and 5 percent. But sales of specialty drugs in the U.S. topped $95 billion, representing about 29 percent of all spending on prescription drugs. Previous research has examined the effects of cost sharing on traditional medications, but comparatively few have examined this issue for specialty drugs.

The study examined peer-reviewed articles that looked at cost sharing and utilization of specialty drugs indicated for rheumatoid arthritis, multiple sclerosis and cancer. Higher cost sharing appears to have a stronger correlation with patients failing to initiate or abandoning a prescription. The association between higher cost sharing and refill behavior is smaller or nonexistent. The study theorizes that patients who have already filled a specialty drug prescription may be less sensitive to costs because such behavior exhibits an understanding of the benefits and/or commitment to treatment.

While drawing such conclusions, the study pointed out gaps in the available research that could improve future understanding of cost-sharing policies. Such work could improve patient outcomes and help avoid higher costs associated with treatment failure resulting in a need for more aggressive treatment.