Updated from 1:56 p.m. EST

Shares of V.I. Technologies ( VITX) were among the best-performing health and pharmaceutical stocks Thursday, rising 69.6% after the company's merger partner received fast-track status from the Food and Drug Administration for its HIV drug.

Privately held Panacos Pharmaceuticals, which plans to merge with V.I during the first quarter of 2005, said the oral drug was well tolerated during phase Ia and phase Ib studies. Full results will be presented at a conference in February. In December, the company initiated a phase IIa trial of PA-457. Results from the trial are expected during the second quarter of 2005. Shares traded up 48 cents to $1.17.

Icon ( ICLR) fell 3.5% after the company posted second-quarter results that beat expectations but warned that full 2005 results would fall short. The clinical research organization posted earnings of 41 cents a share during the second quarter on sales of $79.5 million. Analysts polled by Thomson First Call were expecting earnings of 40 cents a share on sales of $75.9 million. Looking ahead, Icon forecast 2005 earnings of $1.68 to $1.70 a share. Previously, the company forecast earnings of $2 to $2.10 a share. Analysts had been expecting earnings of $2.03 a share. Shares traded down $1.25 to $35.

Shares of Osteotech ( OSTE) fell 10.8% after the company cut its 2004 sales outlook and said a writedown would cause it to post a bigger loss than expected. The $5.8 million writedown will now result in the company posting a loss of 28 cents to 31 cents a share. Previously, Osteotech said it would post a loss of 2 cents to 5 cents a share.

Sales, meanwhile, are now expected to range from $86.5 million to $87.5 million, down from previous guidance of $90 million to $94 million. The provider of human bone and bone connective tissue used for transplantation said the writedown relates to its tissue processing facility in Shrewsbury, N.J. The assets became impaired, it said, because the facility and related assets will no longer be used for tissue processing. Shares traded down 53 cents to $4.38.

Other health care volume movers included StemCells ( STEM), up 22 cents to $5.78; Aastrom Biosciences ( ASTM), up 26 cents to $1.82; Pfizer ( PFE), up 2 cents to $26.29; Biopure ( BPUR), up 3 cents to 57 cents; Merck ( MRK), up 19 cents to $31.53; Amgen ( AMGN), up 58 cents to $62.84; Schering-Plough ( SGP), up 43 cents to $20.79; Genentech ( DNA), up 45 cents to $53.60; and Bristol-Myers Squibb ( BMY), down 4 cents to $24.75.