ICAgen's ( ICGN) shares sank 71% to $1.22 after the company said it would discontinue studies of a drug intended to treat sickle-cell disease in certain patients. The decision followed an analysis of one of its clinical trials by an independent data-monitoring committee. The company will immediately enter an eight-week follow-up period.

Shares of Cell Genesys ( CEGE) lost 8.3% following its earnings report after the close of trading on Thursday. The company reported quarterly revenue of $1.05 million compared with $2.78 million a year ago. Cell Genesys lost $27.9 million, or 60 cents a share, in the second quarter, compared with a loss of $27.4 million, or 60 cents a share, a year earlier. Analysts were expecting the company to lose 62 cents a share. The stock was recently trading at $4.54.

Amgen ( AMGN) fell a day after the company said a federal appeals court reversed a decision on two patent disputes with Transkaryotic Therapies. The federal court did affirm a lower court's decision that Transkaryotic and Aventis Pharmaceuticals infringed Amgen's patent on its anemia drug Epogen. Shares were down 3.1% to $68.73.

Shares of Osteotech ( OSTE) rose after the company said it swung to a profit for the second quarter. Osteotech earned $800,000, or 4 cents a share, compared with a loss of $1.9 million, or 11 cents a share, a year earlier. Revenue remained flat at $25.3 million. Shares were up 10.1% to $4.15.

Adeza Biomedical ( ADZA), a maker of women's health products, gained 11.3% to $16.64 following its earnings report after the close of trading Thursday. For the second quarter, the company reported record sales of $13 million, up 23% from a year ago. Net income in the quarter reached $537,000, or 3 cents a share, including stock-based compensation expenses.

Other health stocks on the move included Acorda Therapeutics ( ACOR), up 8.8% to $3.34; Immtech Pharmaceuticals ( IMM), gaining 7.4% to $5.78; Genentech ( DNA), rising 1.1% to $81.26; ViaCell ( VIAC), up 3.5% to $3.84; CuraGen ( CRGN), adding 3.9% to $3.17; and Oscient Pharmaceuticals ( OSCI), up 16.8% to $1.25.

Meanwhile, Novacea ( NOVC), shares took a 10.2% hit to $7.35; Orthologic's ( OLGC), shares fell 6.1% to $1.54; and CoTherix ( CTRX), was down 2.6% to $7.22.

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