One of the largest pharmacies in the US says it has managed to keep a lid on drug prices

Extreme drug price hikes were a big story in 2015. Now, one of the largest drug stores in the U.S. is crowing about some relatively good news on that front.

CVS Health on Tuesday said drug prices rose only 5% in 2015 for clients of its pharmacy benefits manager. That's less than half the growth rate in 2014.

CVS Caremark is responsible for negotiating with drug companies and health insurers to help come up with the most cost-effective treatment for a patient. That includes negotiating discounts and rebates to prescription drugs, as well as considering switches to other drugs that may be less expensive but have a similar outcome.

A 5% price growth increase may seem like a lot still, but the slowing growth suggests that pharmacy benefits managers are proving effective in controlling prescription drug prices even as drugmakers push costs up sharply. CVS has more than 75 million customers in its pharmacy benefits plan, or about 23% of the US population.

CVS told Forbes that without rebates and making sure patients were taking the most appropriate medications for their conditions, prescription spending growth could have been closer to 12.5% rather than 5%. For the most part, that growth was driven not by specialty medications (which have been the ones experiencing some of the most drastic price increases) but rather the price increases applied to diabetes medication that are used in relatively high volumes.

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