Quarterly earnings reports and new drug trial data were some of the catalysts behind the most actively traded stocks on Wednesday.
Vertex Pharmaceuticals shares jumped after the hepatitis-focused drug developer announced promising preliminary trial data for its experimental hepatitis C drug telaprevir. The Cambridge, Mass.-based company said the relapse rate for patients in a mid-stage clinical trial was less than 10%.
Brian Abrahams, an analyst with CIBC World Markets, said in a note to clients that the data gives "additional confidence in telaprevir's likelihood of ultimate success." Vertex is expected to announce full results of the study in November.
"Based on the data to date, we believe the SVR (sustained viral response) rates for the telaprevir arms will be impressive," said Abrahams, who maintained a "sector outperformer" rating on the stock. "We believe Vertex is undervalued based on the drug's $2 billion-plus potential, and would be buyers ahead of the full phase IIb telaprevir data in the fourth quarter of 2007," he said.
British drug giant GlaxoSmithKline saw shares rise amid heavy trading volume after the company reported second-quarter earnings and announced a $25 billion stock buyback plan.
Wall Street welcomed the public trading debut of BladeLogic with open arms, bidding up shares of the software maker more than 45% above its offering price.
BladeLogic, which specializes in data center automation software, priced its initial public offering at $17 a share on Wednesday, the high end of its expected pricing range. On Tuesday, the Lexington, Mass.-based company raised its price range to $16 and $17 a share from $12 to $14 a share.
Dade Behring Holdings shares rose strongly after the company said it would be acquired by German industrial engineering giant Siemens for $7 billion.
Shares of Amazon.com moved to their highest levels since January 2000 after the Internet retailer said late Tuesday that earnings more than tripled from the year-ago quarter.
Alexion Pharmaceuticals said second-quarter loss narrowed, helped by strong sales of its product, Soliris, a treatment for a rare blood disorder. Second-quarter sales jumped to $9.8 million compared with $300,000 reported a year ago.
On the downside, shares of footwear maker Skechers USA plunged 20% after reporting disappointing second-quarter earnings.
Peter Kang is a markets writer at CNBC.com and can be reached at peter.kang@nbcuni.com.