Shares of

ViroPharma

(VPHM)

were among the worst-performing health-related stocks Thursday, plunging 17% after the drugmaker's first-quarter results came in well below Wall Street's expectations.

The company earned $8.2 million, or 12 cents a share, on revenue of $29.4 million. Analysts polled by Thomson First Call expected earnings of 21 cents a share on revenue of $40.2 million. During the year-earlier quarter, ViroPharma earned $17.4 million, or 36 cents a share, on revenue of $27.2 million.

Looking ahead, ViroPharma continues to project full-year revenue of $160 million to $170 million. Analysts project revenue of $171.5 million. The company sees operating income growth of 10% to 20%. Shares were trading down $1.83 to $9.14.

Shares of

Ariad Pharmaceuticals

(ARIA)

vaulted 24% after a jury said that two drugs sold by

Eli Lilly

(LLY) - Get Report

infringe on one of the company's patents. "The jury ruled unanimously in favor of the plaintiffs in finding that the claims of the NF-(kappa)B patent asserted in the lawsuit are valid and infringed by Lilly with respect to Lilly's osteoporosis drug, Evista, and Lilly's septic-shock drug, Xigris," Ariad said in a press release. Based on the jury's assessment of a reasonable royalty rate, Ariad was awarded damages of about $65.2 million. The jury also awarded damages on an ongoing basis, equal to 2.3% of U.S. sales of Evista and Xigris through 2019, which is when the patent expires.

Lilly said it "strongly disputes the decision" and will seek to have the jury verdict overturned by the trial court judge. If the judge doesn't do so, the company will seek an appeal. Shares of Ariad were trading up $1.32 to $6.86, while shares of Eli Lilly were up 6 cents to $52.02.

Salix Pharmaceuticals

(SLXP)

fell 9% after the drugmaker posted first-quarter results that missed the mark and cut its 2006 earnings outlook. The company earned $3.7 million, or 8 cents a share, on revenue of $41.9 million. Analysts expected earnings of 12 cents a share on revenue of $43.3 million. During the year-earlier quarter, the company earned $3.4 million, or 9 cents a share, on revenue of $28.8 million.

Salix slashed its 2006 earnings forecast to 65 cents a share from an earlier projection of at least 85 cents a share. The company continues to predict revenue of at least $205 million. Analysts project earnings of 85 cents a share on revenue of $204.9 million. Shares were down $1.31 to $12.57.

CoTherix

(CTRX)

rose 11% after the biopharmaceutical company posted better-than-expected first-quarter results. The company posted a loss of $3.9 million, or 14 cents a share, on revenue of $14.5 million. Excluding stock-based compensation costs, the company reported a loss of $2.2 million, or 8 cents a share. Analysts expected a loss of 21 cents a share and revenue of $14.1 million. A year earlier, the company reported a loss of $8.1 million, or 37 cents a share, on revenue of $345,000. "Our first-quarter results reflect our growing commercial presence in the PAH marketplace as Ventavis has become an integral part of PAH therapy," the company said. Shares were trading up 85 cents to $8.55.

Shares of

Symmetry Medical

(SMA)

fell 6% after the orthopedic-device company reported first-quarter results that missed expectations. The company earned $8.4 million, or 24 cents a share, on revenue of $69.6 million. Analysts expected earnings of 25 cents a share on revenue of $71.5 million. During the year-earlier quarter, the company earned $7.7 million, or 22 cents a share, on revenue of $63.8 million.

Looking ahead, Symmetry continues to predict 2006 earnings of $1.08 to $1.11 a share on revenue of $295 million to $303 million. Analysts project earnings of $1.11 a share on revenue of $300.7 million. Shares were trading down $1.20 to $18.30.

Other healthcare volume movers included

Pfizer

(PFE) - Get Report

, up 21 cents to $25.38;

Bausch & Lomb

( BOL), down $2.41 to $41.56;

Novavax

(NVAX) - Get Report

, up 25 cents to $5.91;

Generex Biotechnology

(GNBT)

, up 5 cents to $3.10;

UnitedHealth Group

(UNH) - Get Report

, down 4 cents to $46.57;

Aetna

(AET)

, down 20 cents to $37.02;

WellPoint

(WLP)

, up $1.78 to $69.33;

Boston Scientific

(BSX) - Get Report

, up 32 cents to $21.98;

Amgen

(AMGN) - Get Report

, up 72 cents to $67.11;

Medtronic

(MDT) - Get Report

, down 3 cents to $48.46; and

Johnson & Johnson

(JNJ) - Get Report

, down 11 cents to $58.24.