The Liposome Co. said that on Tuesday it received a broadcomposition of matter patent covering TLC C-53, a liposomalprostaglandin E1, which it is developing as a cell adhesionantagonist.

PGE1 prevents cells involved in inflammation, such asneutrophils, platelets and endothelial cells, from beingactivated by factors such as interleukin-1, tumor necrosisfactor or endotoxin. It also can turn off activated cells.

U.S. patent No. 5,082,664 covers many types of liposomalformulations of PGE1, as well as other prostaglandins andarachidonic acid metabolites.

The Princeton, N.J., company (NASDAQ:LIPO) plans to begin bymidyear Phase I safety trials of C-53 in healthy volunteers. Ifsuccessful, the drug will be tested as a treatment for severalconditions, including adult respiratory distress syndrome,sepsis/trauma syndrome, acute myocardial infarction, and toprevent restenosis following angioplasty.

C-53 acts by increasing the level of cyclic AMP. High levels ofcyclic AMP tell cells to keep cellular receptors off or turn offactivated receptors.

Anne Van Lent, chief financial officer, said the company is theonly one currently working on PGE1. Previous efforts todevelop the drug have been stymied by its instability, its sideeffects -- in particular drops in blood pressure -- and its shorthalf-life. Liposomal encapsulation may overcome theseproblems.

Liposome shares closed down $1 at $20.88. -- Karen Bernstein

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