Shares of Cubist Pharmaceuticals ( CBST) were among the best-performing health-related stocks Thursday, rising 5% after the company posted a third-quarter loss that was smaller than expected.

The company's loss narrowed to $4.5 million, or 8 cents a share, from $17.7 million, or 14 cents a share, a year earlier. Sales surged to $31.8 million from $19.4 million on growth in sales of Cubicin, a bactericidal antibiotic. Analysts polled by Thomson First Call were expecting a loss of 15 cents a share and sales of $32.5 million. Shares recently traded up 98 cents to $19.03.

MedImmune ( MEDI) shares rose 3% after the company posted a huge jump in third-quarter sales on strength of the respiratory treatment Synagis. The company reported a loss of $64.1 million, or 26 cents a share, on sales of $153.6 million. Excluding items, the company had a loss of $60.8 million, or 25 cents a share. Analysts were expecting a loss of 22 cents a share, before items, on sales of $107.5 million. A year ago, the company reported an adjusted loss of $55 million, or 22 cents a share, on sales of $92.7 million.

MedImmune backed its fourth-quarter adjusted earnings guidance of 24 cents to 30 cents a share, which is above analysts' mean estimate of 22 cents a share. Shares gained $1.15 to $34.50.

Shares of Quest Diagnostics ( DGX) fell 1% after the company posted third-quarter earnings that matched expectations, but cut its full-year guidance. The medical testing company earned $135.2 million, or 66 cents a share. Quest said the Gulf Coast hurricanes and an investment writedown cut per-share earnings by 5 cents during the quarter. Without the items, the company would have earned 71 cents a share, matching analysts' forecast. Quest's sales of $1.37 billion came in slightly ahead of analysts' projection of $1.36 billion. A year earlier, the company earned $130.1 million, or 62 cents a share, on sales of $1.29 billion.

Looking ahead, Quest forecast full-year earnings of $2.61 to $2.64 a share on sales growth of 5.5%. Previously, the company predicted it would earn $2.73 to $2.78 a share. The new guidance includes the 5 cents a share related to the hurricanes and investment writedown during the third quarter and an estimated 2 cents a share from continuing disruptions from the hurricanes during the fourth quarter. Quest's test kit manufacturing subsidiary is expected to cut earnings by 5 cents a share as well. Analysts currently project 2005 earnings of $2.76 a share. Shares were trading down 45 cents to $49.14.

Matria Healthcare ( MATR) plunged 19% after the health services company posted mixed third-quarter results and warned that fourth-quarter results would fall short of expectations. The company earned $6.4 million, or 30 cents a share, on sales of $84 million, for the third quarter. Analysts had expected earnings of 30 cents a share, but projected higher sales of $87.3 million. Matria said a drop in orders at its Facet Technologies unit hurt sales during its most recent quarter. A year ago, the company reported earnings of $4.2 million, or 24 cents a share, on sales of $76 million.

Matria Healthcare forecast fourth-quarter earnings of 28 cents to 31 cents a share on sales of $88 million to $90 million. The projection is shy of analysts' projection for earnings of 32 cents a share on sales of $92.1 million. Shares were trading down $7.23 to $31.70.

Shares of Alcon ( ACL) rose 5% after the maker of eye-care products posted third-quarter earnings that topped forecasts. The company earned $295.8 million, or 95 cents a share, on sales of $1.07 billion. Wall Street anticipated earnings of 83 cents a share on sales of $1.09 billion. In the year-earlier quarter, the company earned $194.3 million, or 62 cents a share, on sales of $958.1 million.

Looking ahead, Alcon expects full-year earnings of $3.58 to $3.60 a share on sales of $4.35 billion to $4.4 billion. Analysts forecast earnings of $3.46 a share on sales and $4.41 billion. Alcon shares jumped $6.21 to $134.71.

Other health care volume movers included Pfizer ( PFE), down $1.92 to $22.05; Amgen ( AMGN), down $3.71 to $74.38; Bristol-Myers Squibb ( BMY), down 39 cents to $21.66; BioCryst Pharmaceuticals ( BCRX), down $1.55 to $13.94; Johnson & Johnson ( JNJ), down 13 cents to $64.19; Guidant ( GDT), down 75 cents to $64.15; Novavax ( NVAX), down 10 cents to $3.20; Gilead Sciences ( GILD), down $1.02 to $44.99; Merck ( MRK), up 15 cents to $27.07;; and Schering-Plough ( SGP), down 31 cents to $21.45.

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