Health Winners & Losers: Amylin

Health stocks rose Thursday in a countdown to the Labor Day holiday weekend.

The Nasdaq and Amex biotechnology indices were up 1% and 1.5%, respectively, while a few of Wednesday's losers managed to change course.

Amylin(AMLN Quote), which had dropped 40% over the last two weeks on pancreatitis concerns in patients taking diabetes drug Byetta, rose $1.40, or 6.8%, to $21.88 on Thursday. Shares of Eli Lilly(LLY Quote), Amylin's partner for the drug, rose 4 cents.

Cell Genesys(CEGE Quote), which had given up some 75% after it stopped a late stage study on prostate cancer vaccine GVAX on Wednesday, turned into positive territory on Thursday.

Cell Genesys said the trial was halted because a routine safety check found more deaths had occurred in the GVAX arm of the trial than in the placebo arm. Cantor Fitzgerald downgraded the stock to hold from buy on Thursday, slashing its price target to $2 from $10. The stock did muster some energy, though, adding back 23 cents, or 30%, to $1.02.

Valeant Pharmaceuticals (VRX Quote) sold the rights to the development and commercialization of its epilepsy drug retigabine to GlaxoSmithKline(GSK Quote) in a deal worth up to $820 million. Glaxo will make an upfront payment of $125 million for the drug and for the rights to VRX698 and the other back-up compounds.

The companies plan to co-commercialize retigabine in the U.S., Canada, Australia, New Zealand, and Puerto Rico, and split those profits in half. Valeant will receive up to a 20% royalty on sales in other regions. Valeant shares fell $1.31, or 6.5%, to $18.79, while Glaxo shares were up 50 cents, or 1.1%, to $47.09.