Liposome Technology Inc. (LTI) announced Tuesday that it hasreceived a U.S. patent, No. 5,180,713, for a method of preparinga stable liposome-entrapped amphotericin B drug product.

LTI (NASDAQ:LTIZ) of Menlo Park, Calif., believes the patentedtechnology could be key to the commercialization of aliposome-entrapped version of the drug because it provides theIoptimal meansJ of preserving the particle size of amphotericinB-containing liposomes during storage.

LTI scientists developed the patented method to address theproblem of particle size growth during storage. The LTI processinvolves lyophilizing (freeze-drying) the amphotericin-Bliposome suspension, storing the product in dry form andreconstituting the suspension prior to use, thus stabilizing theparticles in a dry matrix so that fusion and particle growthcannot occur during shipment and storage.

Vestar Inc., a competitor of LTI, on Tuesday issued a statementin response to the patent, saying that the LTI process does notappear to be relevant to its liposomal formulation ofamphotericin B, AmBisome. IWe are very pleased to state thatAmBisome does not change size before lyophilization or afterreconstitution back to a liquid solution, and therefore we do notneed any process to prevent size changes,J the company statedin a press release.

LTILs lipid-complexed amphotericin B product, Amphocil, iscurrently in Phase III clinical trials in the U.S., and thecompany recently filed a product license application (PLA) forapproval of the product in the United Kingdom. LTI does notcurrently use its newly patented process to produce Amphocil,but said the patent may pose a barrier to competitors in theU.S.

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