Vestar Inc. has filed a patent infringement lawsuit in Europeagainst competitor Liposome Technology Inc. (LTI).

San Dimas, Calif.-based Vestar (NASDAQ:VSTR) announcedMonday that the lawsuit, which it filed in the Patents CountyCourt in the United Kingdom, alleges that LTI's anti-cancerproduct Doxil infringes Vestar's European patent, No. 0,179,444,on tumor targeting.

Vestar's patent covers the targeting to tumors of liposomes ofspecific sizes containing chemotherapeutic agents.

Just last week Vestar filed a new drug application (NDA) in theU.S. for DaunoXome, its liposomal formulation of the anti-cancerdrug daunorubicin, for treating AIDS-related Kaposi's sarcoma.

Vestar is currently selling DauonXome in the United Kingdomon a named-patient basis, said Michael Hart, the company'schief financial officer. "This is similar to what we did withAmBisome (a liposomal formulation of the drug amphotericinB) before it was an approved product," Hart told BioWorld.

Meanwhile, LTI (NASDAQ:LTIZ) of Menlo Park, Calif., is in PhaseIII trials in Europe with its Stealth liposome formulated anti-cancer drug Doxil. The drug differs -- for LTI, it's doxorubicin-- but the patient population is the same: AIDS patients withKaposi's sarcoma. LTI will initiate a second Phase III trial ofDoxil for treating KS in the U.S. in the second quarter, said PeterLeigh, the company's chief financial officer. LTI is alsoconducting clinicals in the U.S. and Israel on Doxil for treatingsolid tumors. "We are planning to start a series of Phase II solidtumor trials in non-small cell lung cancer in the U.S. in thesecond quarter," Leigh said.

Asked whether there were any potentially conflicting patentissues between the two drugs in the U.S., Vestar's Hartresponded that "the U.S. situation involves a separate set ofcircumstances."

Vestar sued LTI in January over LTI's newly issued patent on amethod for making liposome-entrapped amphotericin B.

Vestar's stock closed Tuesday at $13.63 a share, up 25 cents;LTI's stock was up 75 cents a share, closing at $8.25.

-- Jennifer Van Brunt Senior Editor

(c) 1997 American Health Consultants. All rights reserved.

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