Shares of Wright Medical ( WMGI) were among the worst-performing health-related stocks Wednesday, falling 21% after the maker of orthopedic devices warned that third-quarter results would fall below its previous guidance.

The company now expects earnings of 10 cents to 11 cents a share on sales of about $73.4 million. Previously, Wright predicted it would earn between 16 cents and 18 cents a share on sales of $77.5 million to $79.5 million. Analysts surveyed by Thomson First Call had been expecting earnings of 17 cents a share on sales of $77.6 million.

Looking ahead, Wright Medical now expects full-year earnings of 66 cents to 70 cents a share on sales of $315 million to $318 million. In July, the company projected that it would earn 85 cents to 88 cents a share on sales of $331 million to $335 million. "These newly revised targets incorporate the preliminary third-quarter results provided today and a fourth-quarter outlook reflecting reduced expectations for the company's domestic biologics product line and its Italian and French markets, modest acceleration of the company's domestic extremities product line growth rate and ongoing solid performances by the company's domestic reconstructive large joint business in line with recent industry rates of growth," the company said. Shares traded down $5.04 to $19.09.

Shares of Human Genome Sciences ( HGSI) plummeted 35% after the biopharmaceutical company said its experimental lupus treatment didn't meet primary endpoints during a Phase II trial. Though LymphoStat-B was safe, well tolerated, and showed signs of clinical effect in patients with systemic lupus erythematosus, the drug failed to meet its primary endpoints of reducing the signs and symptoms of the disease at week 24 or increasing the time to the disease's flare-up to 52 weeks, the company said. Despite not meeting its endpoints, LymphoStat-B "reduced the signs and symptoms of SLE at week 52 at a level of statistical significance in seropositive patients," a subgroup that accounted for 75% of the study's patient population, the company said. Human Genome said it plans to move forward with Phase III development of the drug. Shares were down $4.86 to $9.11.

NutriSystem ( NTRI) rose 10% after the provider of weight management and fitness products boosted its third-quarter sales forecast. The company now expects sales of $64 million to $65 million, up significantly from its prior view of $41 million to $43 million. Analysts had been expecting sales of $43.1 million. The company said it signed 115,000 new customers during the quarter, well above the 65,000 that it had been expecting.

"Third-quarter revenue and customer growth continued to be very strong across all our sales channels. Once again we grew right through the seasonality that is customary in the weight loss market, and we believe we're only beginning to reawaken the NutriSystem brand," the company said. NutriSystem plans to release its third-quarter results on Oct. 25. Shares were trading up $2.58 to $29.39.

Laserscope ( LSCP) rose 6% after Standard & Poor's said it would add the medical laser company to the S&P SmallCap 600 Index after the close of trading on Friday. Laserscope will replace Electronics Boutique Holdings ( ELBO), which is being acquired by GameStop ( GME). Shares of Laserscope recently gained $1.69 to $28.93.

Shares of ev3 ( EVVV) fell 7% after the company posted third-quarter sales that were shy of Wall Street expectations. The endovascular device company reported sales of $33.5 million, up 6% from $31.5 million in the second quarter and up 70% from a year earlier. Analysts were expecting sales of $33.9 million. The company reported U.S. sales of $19.1 million for the third quarter, an increase of 87% compared to a year ago. International sales, meanwhile, climbed to $14.4 million, an increase of 52% on a year-over-year basis. The company plans to release its entire third-quarter report at the end of October.

Looking ahead, the company continues to expect 2005 sales of $130 million to $137 million. Analysts project sales of $135.2 million. Shares were trading down $1.46 to $18.09.

Other health care volume movers included Pfizer ( PFE), down 32 cents to $24.92; Amgen ( AMGN), down 95 cents to $79.15; Merck ( MRK), down 18 cents to $27.02; UnitedHealth Group ( UNH), down 26 cents to $56.80; Johnson & Johnson ( JNJ), down 5 cents to $63; Abbott Labs ( ABT), down 32 cents to $43.69; Genentech ( DNA), down $2.27 to $83.29; and Schering-Plough ( SGP), down 42 cents to $21.15.