Shares of Amedisys ( AMED) were among the worst-performing health-related stocks Thursday, tumbling 24% after the home-health nursing company posted fourth-quarter earnings that were well below forecasts and announced the resignation of its chief financial officer.

The company earned $7.3 million, or 45 cents a share, on service revenue of $118.9 million. Analysts surveyed by Thomson First Call expected earnings of 55 cents a share on revenue of $117.9 million. During the year-earlier period, the company earned $6.1 million, or 39 cents a share, on sales of $64.4 million. Amedisys blamed the weak fourth-quarter earnings on the "transitional cost and delayed timeline expectations for performance improvement from the recent acquisitions of Housecall and Spectracare, the as yet unrealized synergies from the reduction in Housecall's corporate office expenses and the residual impact of last summer's hurricanes."

For 2006, Amedisys continues to predict earnings of $2.33 to $2.43 a share, with sales of $510 million. Analysts project earnings of $2.42 a share on sales of $516 million.

Amedisys said CFO Gregory Browne resigned to pursue other opportunities. The company has hired a search firm to aid it in finding a successor. Browne, meanwhile, will continue to serve as CFO until a replacement is found and transitioned, the company said. Shares were trading down $9.80 to $30.80.

GTC Biotherapeutics ( GTCB) shares plunged 39% after the biopharmaceutical company said an advisory committee of the European Medicines Agency plans to issue a negative opinion related to the company's application for ATryn, a recombinant form of human antithrombin. "On the basis of recent conversations, GTC understands that the CHMP, after excluding data from pregnant patients, determined that an insufficient number of surgical patients were enrolled to support approval," the company said in a statement. GTC said it plans to use the appeals process to ask the agency to re-examine the application. Shares were trading down 87 cents to $1.38. Nearly 21 million shares have changed hands, compared with an average daily volume of just 764,219 shares.

Kos Pharmaceuticals ( KOSP) tumbled 16% after the drugmaker posted lower-than-expected fourth-quarter earnings and warned that first-quarter earnings would be significantly below forecasts. The company earned $26.2 million, or 53 cents a share, on sales of $213.9 million. Excluding items, the company earned $35.1 million, or 71 cents a share. Analysts expected earnings of 80 cents a share, before items, on sales of $210 million. During the year-earlier period, the company earned $53 million, or $1.15 a share, on sales of $150.7 million. Excluding items, the company earned $33 million, or 72 cents a share, a year earlier.

Looking ahead, Kos Pharmaceuticals forecast a first-quarter loss of 5 cents to 10 cents a share, with sales of $170 million to $175 million. Excluding stock-based compensation costs, the company sees earnings of 5 cents to 10 cents a share. Analysts project earnings of 72 cents a share on sales of $201.2 million. Kos blamed the first-quarter shortfall on recent inventory management agreements that it signed with three pharmaceutical wholesalers. Shares were down $7.92 to $41.85.

Shares of Nastech Pharmaceutical ( NSTK) climbed 11% after the pharmaceutical company acquired the rights to Galenea's RNAi intellectual property portfolio and other RNAi technologies. "This acquisition strengthens Nastech's existing RNAi therapeutics pipeline through the addition of Galenea's ongoing programs that target influenza and other respiratory diseases," Nastech said in a statement. Galenea, a biotech firm, also agreed to sell its research and intellectual property relating to pulmonary drug delivery technologies. Financial terms of the deal were not disclosed. Shares of Nastech were trading up $1.96 to $20.63.

Shares of Pharmion ( PHRM) fell 7% after the pharmaceutical company posted fourth-quarter results that missed expectations and issued a 2006 sales guidance below forecasts. The company reported a loss of $16.4 million, or 51 cents a share, on sales of $56.4 million. Excluding items, the company earned $4.8 million, or 15 cents a share. Analysts expected earnings of 21 cents a share on sales of $58.3 million. During the year-earlier period, the company earned $2.6 million, or 8 cents a share, on sales of $51.5 million.

Pharmion said it expects 2006 sales will be in line with 2005 sales of $221.2 million. Analysts project sales of $239.3 million. Shares were down $1.30 to $15.36.

Other health care volume movers included Pfizer ( PFE), unchanged at $26.19; Merck ( MRK), down 52 cents to $35.40; Amgen ( AMGN), down 43 cents to $74.65; Boston Scientific ( BSX), up 33 cents to $24.46; Elan ( ELN), up 1 cent to $14.27; Bristol-Myers Squibb ( BMY), down 9 cents to $23.27; Schering-Plough ( SGP), down 34 cents to $18.89; and Johnson & Johnson ( JNJ), down 32 cents to $58.71.

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