Appeal No. 2004-2202 Page 11
Application No. 10/016,324
lines 7-13: “Lipid soluble drugs, which are contained predominantly in the lipid bilayer
region of liposomes, gradually become associated with endogenous lung lipids . . ., and
in this form, the drugs can traverse the blood-gas barrier to enter the pulmonary
circulation.”
Therefore, those skilled in the art would have expected that, when a liposome-
encapsulated drug is administered by inhalation, any drug that enters the bloodstream
would be in the form of free drug, as opposed to liposome-encapsulated drug. For this
reason, we agree with Appellants that those skilled in the art would not have been
motivated to combine Klibanov’s polymer-coating of liposomes with Mihalko’s method of
administering liposomes by inhalation in order to gain the advantage of long circulation
times taught by Klibanov. Those skilled in the art would have expected that the
composition of the liposomes would have no effect on the length of systemic circulation
because the liposomes themselves would not be expected to enter the bloodstream.
We therefore agree with Appellants that Mihalko and Klibanov do not support a
prima facie case of obviousness. The rejection based on those references is reversed.
The examiner also rejected dependent claims 31-33 as obvious in view of
Marshall, alone or combined with Mihalko, and further combined with Gao, and rejected
dependent claims 49-57 as obvious in view of Mihalko, Klibanov, two secondary
references, and “applicant’s statements of prior art.” Our analysis with respect to the
rejections of claim 29 apply to these rejections as well, since the additional references
do not make up for the deficiencies (discussed above) of Marshall, Mihalko, and
Klibanov.
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