Shares of

Kos Pharmaceuticals

( KOSP) were among the best-performing health-related stocks Thursday, rising 6% after the company posted second-quarter results that were better than expected.

The drug maker earned $28.9 million, or 61 cents a share, on sales of $179.4 million. Analysts surveyed by Thomson First Call were expecting earnings of 56 cents a share on sales of $173.3 million. A year ago the company reported pro forma earnings of $21.4 million, or 46 cents a share, on sales of $120.3 million.

Looking ahead, Kos Pharmaceuticals now expects full-year earnings that will climb to the high end of its previous guidance of $2.65 to $2.75 a share. Sales, meanwhile, will be between $720 million and $730 million, up from previous guidance of $710 million to $720 million. The new earnings guidance includes one-time charges, which had been excluded from earlier guidance. Analysts had been expecting earnings of $2.63 a share on sales of $727.2 million. Shares were trading up $3.96 to $75.86.

Syneron Medical

(ELOS)

fell 6% Thursday after the company posted second-quarter results that topped forecasts. The company, which had seen its shares climb by more than 26% over the past two months, reported pro forma earnings of $9.2 million, or 34 cents a share, on sales of $20.1 million. Analysts were expecting earnings of 33 cents a share on sales of $19.9 million. A year ago the company posted pro forma earnings of $6.4 million, or 30 cents a share, on sales of $13.4 million. Syneron's most recent results were fueled by strength across all of its platforms.

Looking ahead, Syneron reiterated its 2005 sales guidance of $84 million to $85 million. On June 30, the company raised its sales guidance to $84 million to $85 million, up from earlier guidance of $78 million to $80 million. Analysts are expecting sales of $86 million. Shares were trading down $2.59 to $40.75.

Shares of

Wellcare Health Plans

(WCG) - Get Report

rose 3% after the company posted second-quarter earnings that beat forecasts and raised its full-year earnings guidance. The health care provider earned $14.2 million, or 36 cents a share, on sales of $453.7 million. Excluding a 2-cent charge, the company would have earned 38 cents a share. Analysts were expecting earnings of 35 cents a share on sales of $431 million. Looking ahead, Wellcare now expects 2005 earnings of $63 million to $64 million, or $1.61 to $1.63 a share, on sales of $1.82 billion to $1.84 billion. Previously, the company expected earnings of $60 million to $62 million, or $1.50 to $1.55 a share, on sales of $1.72 billion to $1.75 billion. Analysts had been expecting earnings of $1.51 a share on sales of $1.76 billion. Shares were trading up $1.17 to $39.78.

Human Genome Sciences

( HGSI) fell 7% after the company said it would sell $230 million in convertible subordinated notes in a private offering. The biopharmaceutical company said it plans to use all of the proceeds to repurchase its 5% convertible subordinated notes due 2007 and its 3.75% convertible subordinated notes also due 2007. Shares were trading down $1.06 to $13.75.

Shares of

Valeant Pharmaceuticals International

(VRX)

rose 2% after the specialty pharmaceutical company posted second-quarter results that were better than expected. The company reported pro forma earnings of $7.6 million, or 8 cents a share, on sales of $205 million. Analysts were expecting earnings of 4 cents a share on sales of $190.8 million. A year ago the company posted pro forma earnings of $2 million, or 2 cents a share, on sales of $170.4 million. During the most recent period, sales to Latin America rose 13% to $41.4 million, up from $36.5 million a year ago. European product sales, meanwhile, rose 3% to $61.8 million, up from $60.1 million a year ago. North American sales jumped 71% to $60.4 million, up from $35.3 million a year ago. Finally, gross margin climbed to 71% in the second quarter, up from 69% last year. Shares were trading up 42 cents to $20.24.

Other health care volume movers included

Pfizer

(PFE) - Get Report

, down 19 cents to $26.74;

Amgen

(AMGN) - Get Report

, down $1.16 to $82.84;

Teva Pharmaceutical

(TEVA) - Get Report

, up 14 cents to $32.73;

Merck

(MRK) - Get Report

, down 36 cents to $30.46;

Schering-Plough

( SGP), down 21 cents to $21.21;

Elan

(ELN)

, down 9 cents to $7.90; and

Johnson & Johnson

(JNJ) - Get Report

, down 55 cents to $64.32.