Thursday's Health Winners & Losers

Updated from 12:51 p.m. EDT

Earnings beats and positive news out of Amgen (AMGN Quote) were supporting the health care sector Thursday, even as the major markets were sliding.

Amgen said Thursday that its Aranesp anemia drug was not contributing to the deaths of patients in a Phase III lung cancer trial. The biotech giant added $2.31, or 3.6%, to $62.32.

Gilead Sciences (GILD Quote) reported a 55% jump in first-quarter earnings from a year ago, topping Wall Street's consensus forecast. Gilead was higher by $3.28, or 4.2%, at $81.71.

Both Amgen and Gilead are components of the Amex Biotechnology Index, but their gains merely buoyed the index's gain of 0.7%.

Among others reporting earnings, Dow Jones Industrial Average component Merck (MRK Quote) posted first-quarter earnings that were in line with estimates. Meanwhile, Schering-Plough (SGP Quote) topped estimates.

The Amex Pharmaceutical Index, of which both are components, was higher by 0.9%.

Among other winners, Monogram Biosciences (MGRM Quote) soared 9.5% to $2.08. Arena Pharmaceuticals (ARNA Quote), which posted a widening first-quarter loss that was still better than the Thomson First Call average estimate, was higher by 7.9% at $12.25. St. Jude Medical (STJ Quote) rose 5.5% after raising its full-year outlook.

Decliners included UnitedHealth (UNH Quote), which beat estimates and guided in line for the second quarter and full year. Despite the positive news, the stock lost $2.16, or 4%, to $52.05.