Wednesday's Health Winners & Losers

Updated from 1:56 p.m. EDT

The health care sector mirrored the mixed nature of the major indices Wednesday, as positive clinical data boosted biotech names while earnings fears sank big pharmaceutical stocks.

Avanir Pharmaceuticals (AVNR Quote) was the day's best performer. The stock soared 308.7% after the company's Zenvia drug showed positive results in a Phase III clinical trial when used as treatment for diabetic neuropathic pain. Shares of Avanir were up $3.92 at $5.19.

Shares of Introgen Therapeutics (INGN Quote) also surged after the company late Tuesday announced positive early phase results for INGN 401, its proposed treatment for lung cancer. Introgen added 38 cents, or 7.4%, to $5.54.

Among other health care winners, Atherogenics (AGIX Quote) jumped 19.9% to $3.86, and Dendreon (DNDN Quote) was higher by 2% to $16.01.

On the other hand, shares of Gilead Sciences (GILD Quote) slumped 1.2% ahead of the company's first-quarter earnings report, due out after the close. The company should earn 79 cents a share, according to Thomson First Call, up from 55 cents a share in the year-ago period.

Gilead's loss offset a 3.6% advance in shares of MedImmune (MEDI Quote) on the Amex Biotechnology Index, which was down 0.4%.

The Amex Pharmaceutical Index was down 0.2%, following a 1.6% loss in Abbott Laboratories (ABT Quote). Earlier, the company posted a first-quarter profit of $697.5 million, or 45 cents a share, down 19% from the year-ago quarter. While Abbott upped its second-quarter and full-year guidance, the stock lost 97 cents at $58.03.

Merck (MRK Quote) also traded lower ahead of its first-quarter earnings report. The drug maker, scheduled to post results before the market opens Thursday, is expected to say it had a profit of 73 cents a share. Shares of Merck were down 32 cents, or 0.6%, to $49.69.

Along with Merck, also on the schedule for the next session are St. Jude Medical (STJ Quote), down 0.8%; UnitedHealth (UNH Quote), which lost 0.8%; and Wyeth (WYE Quote), which closed down a penny.