Threshold Pharmaceuticals ( THLD) jumped more than 15% in extended trading Wednesday after the Redwood City, Calif., company announced positive results for midphase testing of its advanced pancreatic cancer treatment. The company said its combination of glufosfamide and gemcitabine induced partial response -- defined here as a 30% combined shrinkage of the largest-diameter target lesions -- in 21% of patients tested. Stable disease was seen in 36% of the test subjects. The drug combination also was "generally well tolerated," Threshold said, "with no new unexpected adverse events."

In one possible piece of bad news, Threshold added that the drugs may jointly induce slightly more treatment-related nephrotoxicity, or toxicity to kidney cells, than either drug would do alone. But shares were trading up 50 cents, or 15.6%, to $3.70.

On2 Technologies ( ONT) gained after an analyst with ThinkEquity Partners began coverage on the video compression technology firm with a buy rating, targeting a per-share price of $1.40. Shares of the Clifton Park, N.Y.-based company were adding 4 cents, or 3.7%, to $1.13.

Salt Lake City's Sento ( SNTO) tanked after it swung to a fiscal second-quarter loss. The customer-service small-cap said it lost $2.6 million, or 65 cents a share, in the quarter ended Sept. 30, down from a $310,000 profit, or 8 cents a share, a year ago. Revenue rose 39% to $13.6 million -- which, the company pointed out, topped its own earlier target range of $12 million to $12.5 million. Shares were losing 63 cents, or 19.4%, to $2.61.

Corcept Therapeutics ( CORT) sunk after the small pharmaceutical company announced it might be delisted from the Nasdaq for failing to have at least $10 million in stockholders' equity. Corcept falls short of that amount by about $3 million, according to its most recent quarterly filing on Sept. 30. The Menlo Park, Calif.-based company has appealed the decision and will be heard by the Nasdaq's delisting panel within 45 days, after which the exchange will make its final decision. Shares were down 12 cents, or 10.2%, to $1.06.

Animal health care company VCA Antech ( WOOF) slipped on disappointing 2007 earnings guidance. The Los Angeles-based company's revenue outlook is bright, ranging from $1.05 billion to $1.08 billion. This nicely covers analysts' $1.06 billion estimates, according to Thomson Financial. But full-year per-share income is expected to be between $1.27 and $1.31, which falls short of the $1.33-a-share consensus. Shares were down 29 cents to $32.00.

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