Recruiting in China

The purchase of China’s WuXi PharmaTech Inc. will give Charles River Laboratories International Inc. the ability to offer drug makers one-stop shopping for preclinical drug development and testing, executives of both companies said yesterday.

Charles River Labs, a drug testing contractor based in Wilmington, agreed to acquire Shanghai’s WuXi (pronounced who-shee) in a cash and stock deal valued at about $1.6 billion.

The alliance is a good fit because the two companies serve a similar client base of leading pharmaceutical and biotechnology companies in the United States and Europe but provide different services, said James C. Foster, chief executive of Charles River, who will lead the combined company.

While the Massachusetts company conducts animal tests for drug developers before clinical trials, its new Chinese partner, among other things, manufactures the primary ingredient in drugs — known in the industry as the API, or active pharmaceutical ingredient, the substance in drugs that is biologically active.

“We’re doing this because our clients, particularly large pharmaceutical and biotechnology companies, want to buy an increasing number of services from a smaller number of providers,’’ Foster said in an interview. “We want to be one of those providers.’’

Edward Hu, the WuXi chief operating officer who oversees US operations, said the deal will allow his company to expand faster, and serve a broader customer base, than it could have on its own.

“It creates a formidable company in the early development space,’’ Hu said in an interview, citing the ability to handle a range of services for clients, from designing molecules to safety and animal testing. “No other service provider has this capability today. This is going to reshape the pharmaceutical and biotechnology industry.’’

But investors apparently thought WuXi stockowners got the better part of the deal, which the boards of both companies have approved. Shares of Charles River tumbled $6.22 (15.6 percent) to $33.55 on the New York Stock Exchange yesterday, while WuXi shares vaulted $2.84 to $19.41, a 17.1 percent gain.

Charles River agreed to pay $21.25 a share for the Chinese company. That includes $11.25 in cash and $10 in Charles River common stock. The deal represents a more than 25 percent premium over WuXi’s closing stock price Friday. It is expected to be completed some time before the fourth quarter.

The merger reflects a consolidation trend among both drug makers and the companies that provide services to them.

Increasingly, many drug makers have been outsourcing development and testing services to contract research organizations, such as Charles River and WuXi, and focusing their own efforts on clinical trials and marketing. The outsourcing business, which allows drug makers to cut costs and increase their speed to market, has been growing by an estimated 30 percent annually.

“This is another way of reducing risk,’’ said Harry Glorikian, managing partner at Scientia Advisors, a Cambridge consulting firm that focuses on life sciences. “It’s less risky for large pharmas to outsource their drug development functions and become marketing shops pushing these drugs onto consumers. When you think about it, this is similar to Procter & Gamble or Dell outsourcing component design.’’

Under their definitive agreement, the combined company will retain the name Charles River Labs and its global headquarters in Wilmington. The Chinese operation will continue to be called WuXi and be run by its existing management team of mostly Chinese-born, US-educated executives.

WuXi was one of the companies visited by Governor Deval Patrick on a trade mission he led to China in 2007. The company currently serves about 20 customers from Massachusetts, including Vertex Pharmaceuticals Inc. of Cambridge.

While the deal helps to cement the role of China as low-cost venue for drug development, Charles River’s Foster said he expects operations in Wilmington will expand as the company grows. Charles River also plans to reopen in 2012 an animal testing site in Shrewsbury where it suspended operations early this year because of a slowdown in business from its customers in the Boston area, Foster said.

“Our footprint will get larger in Massachusetts,’’ he said.

Charles River, which had $1.2 billion in sales last year, employs about 8,000 workers worldwide, including more than 800 in Massachusetts. The company was founded by Foster’s father, veterinarian Henry Foster, in 1947. It went public on the Nasdaq exchange in 1968, and was purchased by medical technology company Bausch & Lomb in 1984.

A management group, led by James Foster, repurchased the company in 1999 through a leveraged buyout and took it public again in 2000, this time on the New York Stock Exchange.

WuXi, a 10-year-old company that posted revenue of $270 million last year, is the largest Chinese maker of chemical compounds for the pharmaceutical industry. It acquired three US research sites in 2008 when it bought Minnesota-based AppTec Laboratory Services Inc. WuXi employs about 4,000 workers worldwide.