Pain Therapeutics ( PTIE) was among the worst-performing health-related stocks Tuesday, plummeting 19% after the company's Phase III trial of its investigational pain drug Oxytrex didn't result in statistical significance due to high dropout rates. The drug did exceed the company's target of 25% improvement in physical dependency, with Oxytrex cutting dependency by 28% compared to an equivalent does of oxycodone. However, Pain Therapeutics said all study arms had high dropout rates. The company said it expects to discuss methodologies with the Food and Drug Administration to overcome statistical limitations imposed by high dropout rates. The stock was down $1.61 to $6.90.

Cooper Cos. ( COO - Get Report) fell 20% after the contact lens company lowered its guidance for the fourth quarter and next two years, citing weak sales and foreign currency rates. The company cut its fourth-quarter earnings projection to 83 cents to 86 cents a share from an earlier forecast of 96 cents to 99 cents. Cooper lowered its sales projection to $219 million to $222 million from a range of $238 million to $242 million. According to Thomson First Call, analysts had forecast earnings of 97 cents a share and sales of $235.8 million.

For fiscal 2006, Cooper lowered its earnings forecast to a range of $3.60 to $3.70 a share from $4 to $4.10. The company tempered its sales projection to $933 million to $946 million from $983 million to $998 million. For the following year ending in October 2007, Cooper sees earnings of $4.30 to $4.40 a share and sales of $1.045 billion to $1.06 billion. The company's previous fiscal 2007 forecast called for earnings of $4.75 to $4.85 a share and sales of $1.097 billion to $1.12 billion. Cooper shares recently traded at $52.08, down $12.74.

Cyberonics ( CYBX) rose 2.6% after the company posted a second-quarter loss of $22.1 million, or 88 cents a share, wider than its loss of $2 million, or 8 cents a share, a year earlier. The medical device company's revenue increased to $29.1 million from $25.4 million last year. Analysts expected a loss of 83 cents a share and revenue of $30.5 million, according to First Call. For fiscal 2006, Cyberonics expects revenue of $140 million, compared with Wall Street's forecast of $143.6 million. The stock was up 73 cents to $29.10.

Abbott Laboratories ( ABT - Get Report) and Myriad Genetics ( MYGN - Get Report) said they have extended their research alliance in pharmacogenetics. This research focuses on how a person's genetic makeup affects his or her response to certain medicines. Abbott will fund the research and Myriad will use its technology and mutation screening software to analyze samples. Financial terms of the deal were not disclosed. In other Abbott news, Caris & Co. downgraded the stock to average from above average. Abbott shares were down $1.06, or 2.6%, to $39.31 and shares of Myriad rose 24 cents, or 1.3%, to $19.53.

Other health stocks trading actively Monday were Pfizer ( PFE - Get Report), down 41 cents to $21.33; Dynacq Healthcare ( DYII), up 60 cents to $3.40; Merck ( MRK - Get Report), down 2 cents to $30.45; Schering-Plough ( SGP) up 5 cents to $19.65; and Biogen Idec ( BIIB) down 95 cents to $44.17.