Liposome Technology Inc. has presented preclinical datashowing that its Stealth liposome technology worked betterthan free drug in delivering anti-cancer drugs to tumors inseveral mouse models.

The Menlo Park, Calif., company's (NASDAQ:LTIZ) Stealthtechnology coats liposomes with a polymer that enables thecarrier to evade recognition and uptake by the host's immunesystem. The data were presented last week at the AmericanAssociation for Cancer Research meeting in San Diego.

In one leukemia model, Stealth-vincristine increased life spanby 44 percent, compared with 27 percent for free vincristine.In a second model, S-vincristine increased life span by 199percent, compared with 79 percent for free vincristine.

In a colon cancer model using the anthracycline anti-cancerdrugs doxorubicin and epirubicin, tumor-free survival for atleast 120 days ranged from 60 percent to 100 percent in themice treated with Stealth anthracyclines. In contrast, no micetreated with free drug or drug encapsulated in conventionalliposomes survived to day 120.

In a colon cancer model treated with vincristine, 10 percent ofthe mice treated with free drug survived at day 60. Eightypercent of the mice treated with S-vincristine survived.

Stealth was also tested in a highly metastatic breast cancermodel, in which 50 percent of tumors normally metastasize.Using S-doxorubicin, none of 18 tumors metastasized, vs. 11 of17 treated with free drug.

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