Report: 2015 US drug spending rose 5 pct., half 2014's rise

Spending on prescription drugs for insured Americans rose 5 percent last year, driven by increased use and higher prices, mainly for very expensive drugs termed specialty medicines. Still, the increase was half the rate in 2014, which saw the biggest jump since 2003.

A report by the largest U.S. prescription benefit manager, Express Scripts, also found the average price of brand-name drugs increased 16.2 percent in 2015. It's jumped 98.2 percent since 2011. Despite intense criticism of soaring drug prices from patients and politicians, last year prices jumped more than 20 percent for one-third of brand-name prescription drugs.

Express Scripts forecasts drug spending will rise 6 percent to 8 percent annually through 2018. The trends don't bode well for insurers and government health programs trying to hold down medication costs.