Shares of biopharmaceutical company CytRx ( CYTR) gained 3.4% to $2.15 after the company said its RXi Pharmaceuticals subsidiary is licensing technology to the University of Massachusetts Medical School. The technology involves so-called RNA interference, which targets disease-associated genes.

West Pharmaceutical Services' ( WST) shares gained 3.2% to $48.21 after the company announced that 2006 sales should exceed analysts' estimates.

While the company expects to earn 39 cents to 43 cents a share, excluding certain charges, compared with estimates of 43 cents, sales for the full year could reach $913 million compared with the $900.65 million analysts were expecting.

Shire ( SHPGY) received European approval for its drug Elaprase as a long-term treatment of Hunter syndrome, a rare and life-threatening disease affecting metabolism. Shares gained 1.9% to $63.44.

Chelsea Therapeutics' ( CHTP) stock jumped 7.3% to $3.84 after the company announced positive trial results on its Droxidopa treatment for a disorder associated with Parkinson's disease.

Shares of Allergan ( AGN), the maker of wrinkle-fighting Botox, gained 2.1% to $117.90 after Prudential Equity Group's analyst Larry Biegelsen initiated coverage of the stock with an overweight rating and a 12- to 18-month price target of $138 per share.

"AGN's large and diverse portfolio of ophthalmic pharmaceutical, medical aesthetic and obesity products have significant growth potential and limited exposure to reimbursement pressure in our view," Biegelsen wrote in a research report Thursday.

Among other health stock winners were biotechs Genentech ( DNA), gaining 4.2% to $87.29; Amgen ( AMGN), up 1.4% to $72.03; Celgene ( CELG), 1.4% higher to $56.01; Gilead ( GILD), up 1.7% to $65.79; and Genzyme ( GENZ), rising 1.8% to $67.80; as well as pharmaceuticals companies Sanofi-Aventis ( SNY), 1.5% higher to $45.47; and Bayer ( BAY), up 2.2% to $54.16.

Among the losers were Endo Pharmaceuticals ( ENDP), off 1.6% to $29.16; Nektar Therapeutics ( NKTR), down 1.6% to $13.95; Atherogenics ( AGIX), falling 3% to $11.66; and Penwest Pharmaceuticals ( PPCO), 2.4% lower to $15.68.