Thursday's Health Winners & Losers

On Thursday health stock investors reacted to clinical data and regulatory news that sent some biotech names hurdling in both up and down directions.

Biogen Idec(BIIB Quote), however, really moved on late Wednesday news that it has received no definitive offers from potential acquirers after a well-publicized effort to lure a buyer. The news took shares down $17.97, or 23.7%, to $57.91.

Two stocks that were hot off of clinical data: Rigel Pharmaceuticals(RIGL Quote) and Savient Pharmaeuticals(SVNT Quote).

Rigel added a whopping $16.64, or 208%, to $24.64 after reporting positivemidstage trial data for its experimental rheumatoid arthritis treatment candidate. Rigel said the drug worked as early as one week after administration and was well-tolerated. It plans to initiate the next clinical trial for the drug as an rheumatoid arthritis treatment in 2008.

Also, Savient said Thursday that in two late-stage studies its drug Puricase effectively treated patients with gout who've tried other treatments with no success. Savient plans to file a biologics licenses application with the Food and Drug Administration in 2008 based on the results from the trials. If Puricase gets regulatory approval, it will be the only treatment for unsuccessfully-treated patients. Shares added $2.63, or 18.2%, to $17.09.

Rigel and Savient weren't enough to hoist the Nasdaq biotechnology index into the green -- the index was down 7.43, or 0.9%, at 850.19 on Thursday.