NEW YORK (CNNMoney.com) -- The worldwide drug market will continue to grow in 2007, but at a slightly slower pace as patent losses on blockbuster drugs take their toll, according to a forecast from IMS Health.

Research firm IMS (up $0.17 to $27.00, Charts) projects that worldwide pharmaceutical sales will grow 5 to 6 percent in 2007, to a range of $665 billion to $685 billion. This is down slightly from the 2006 growth rate of 6 to 7 percent.

Overall sales will be driven by 13 to 14 percent growth in the biotech and generic drug industries in 2007, IMS said.

But new drugs are "not keeping pace with the loss of patent protection by established products" and the industry is shifting from "mature markets to emerging ones," said Murray Aitken, senior vice president for IMS, in a press release.

Thirty new drugs are expected to be approved in 2006, and a comparable number of 25 to 35 new approvals are expected for 2007, said IMS. Meanwhile, more than $16 billion worth of brand-name pharmaceuticals are expected to lose patent protection in 2007, on top of $23 billion worth of products slated to lose protection in 2006, according to the research firm.

Developing markets will play an increasingly important role in growing the drug market, said IMS, while the U.S. role will diminish in importance.

The research firm said countries with per capita gross national income of less than $20,000 will be responsible for 30 percent of next year's growth, nearly double the 2006 rate of 17 percent. The U.S. will be responsible for 36 percent of market growth in 2007, down from its level of 54 percent five years ago.

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