Appeal No. 95-4004
Application 07/858,171
head group. Included in this class are the phospholipids
such as phosphatidylcholine (PC), PE, phosphatidic acid
(PA), phosphatidylinositol (PI), and sphingomyelin (SM),
where the two hydrocarbon chains are typically between
about 14-22 carbon atoms in length, and have varying
degrees of unsaturation. Also included in this class
are the glycolipids, such as cerebrosides and gangliosides.
Another vesicle-forming lipid which may be employed is
cholesterol and related sterols. In general, cholesterol
may be less tightly anchored to a lipid bilayer membrane,
particularly when derivatized with a high molecular weight
polymers [sic], such as polyalkylether, and therefore be
less effective in promoting liposome evasion of the RES
in the bloodstream.
The specification’s teaching that cholesterol and related sterols
derivatized with polyalkylether are suitable as vesicle-forming
lipids for inclusion in liposome compositions containing
therapeutic compounds for use in treating systemic infection
localized at a site by intravenous injection is not a teaching or
even a suggestion of the method of the claims on appeal. In
short, the examiner clearly erred in finding that cholesterol and
related sterols derivatized with polyalkylether are diacyl-chain
amphipathic vesicle-forming lipids derivatized with polyethylene
glycol having a molecular weight between about 350 and 5,000
daltons. Therefore, we must reverse the examiner’s holding that
Claims 1 and 4-7 on appeal are unpatentable under 35 U.S.C. § 103
over the teaching of Popescu in view of the teachings of
Radhakrishnan and McGregor.
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