Updated from 3:19 p.m. EST

Shares of

Affymetrix

(AFFX)

were among the best-performing health-related stocks Thursday, rising 14.3% after the company posted fourth-quarter earnings and sales that easily surpassed analysts' expectations.

The company earned $27.1 million, or 41 cents a share, on sales of $107.7 million. Analysts were expecting earnings of 37 cents a share on sales of $103.8 million. Looking ahead, Affymetrix expects first-quarter earnings of 20 cents a share on sales of about $90 million. Analysts had been expecting earnings of 23 cents a share on sales of $89.9 million. Despite lower-than-expected first-quarter earnings guidance, the company expects full-year earnings of about $1.12 a share on sales of $405 million. Analysts had been expecting earnings of $1.10 a share on sales of $393.6 million. Shares traded up $5.20 to $41.53.

Amgen

(AMGN) - Get Report

fell 3.1% after the company missed fourth-quarter earnings estimates. Excluding items, the company earned 58 cents a share on sales of $2.9 billion. Analysts were expecting earnings of 61 cents a share on sales of $2.84 billion. Looking ahead, Amgen said that it expects to post 2005 earnings of $2.70 to $2.85 a share. Analysts had been expecting earnings of $2.85 a share. Sales, meanwhile, are expected to grow by high single digits to low teens on a percentage basis. Analysts had been expecting sales of $12.07 billion, an increase of 14% over 2004 results. Shares traded down $1.98 to $61.58.

Shares of

Sonus Pharmaceuticals

(SNUS)

rose 2.4% after the company's bladder cancer drug received orphan status from the Food and Drug Administration. The company said it is currently in discussions with the FDA to finalize phase III protocol for Tocosol Paclitaxel, which Sonus believes will be initiated in 2005. Shares traded up 9 cents to $3.85.

Millennium Pharmaceuticals

(MLNM)

fell 2.5% after the company posted a fourth-quarter loss that was wider than expected. Excluding items the company posted a loss of $84.7 million, or 28 cents a share, on sales of $100.3 million. Analysts were expecting a loss of 25 cents a share on sales of $103.5 million. A year ago the company posted a loss of $91.8 million, or 30 cents a share, on sales of $85.4 million. Shares traded down 24 cents to $9.21.

Other health care movers included

Aastrom Biosciences

(ASTM)

, down 18 cents to $3.02;

Pfizer

(PFE) - Get Report

, up 9 cents to $24.68;

Schering Plough

(SGP)

, down 77 cents to $19;

StemCells

(STEM)

, up 11 cents to $4.50;

Johnson & Johnson

(JNJ) - Get Report

, down 43 cents to $64.22; and

Merck

(MRK) - Get Report

, up 1 cent to $31.18.