Charles River to spend $1.6b for WuXi Pharma

Purchase would be largest takeover of Chinese firm

NEW YORK - Charles River Laboratories International Inc agreed to buy WuXi PharmaTech (Cayman) Inc for about $1.6 billion to expand in China, where revenue from drug-testing services is growing as much as 30 percent a year.

Charles River will pay $21.25 a share, comprising $11.25 in cash and $10 in stock, for each WuXi American depositary share, the companies said in a statement on Monday. The offer is 28 percent more than WuXi's closing price of $16.57 in New York Stock Exchange trading on April 23.