UnitedHealth, Pfizer lead S&P health index lower

S&P's health care index, which tracks a wide mix of health care-related companies, fell 2.7 percent since March 31, while the broader S&P 500 index declined 3.4 percent. Shares of Minnetonka, Minn.-based UnitedHealth lost 24 percent over the quarter as the health insurance industry faced higher medical costs and membership declines.

Both UnitedHealth and its peer Coventry Health Care Inc. have cut full-year profit outlooks for 2008. Shares of Bethesda, Md.-based Coventry fell 22 percent.

Shares of New York-based drug developer Pfizer Inc. fell 17.4 percent as generic competition continued hampering the company's revenue and safety concerns threatened to stunt the growth of its anti-smoking drug Chantix. But, pharma peer Schering-Plough topped the index with a 36 percent gain as Wall Street continues to look favorably on the Kenilworth, N.J.-based company because of a lack of significant generic competition and strong pipeline of products.

The gains mark a sharp turnaround for Schering. On March 31, the last day of the prior quarter, the stock fell 31 percent after the company released negative study results on blockbuster cholesterol drug Vytorin.

Both Milford, Mass.-based Waters Corp. and Waltham, Mass.-based PerkinElmer Inc. counted themselves among the top gainers as the demand for drug development services and equipment remains strong. Waters gained 17 percent and PerkinElmer gained 14 percent during the quarter.