Appeal No. 2004-2202 Page 9
Application No. 10/016,324
such a coating would enable the liposomes to circulate longer and reach the target
tissue as taught by Klibanov.” Id.
Appellants argue that
it is clear from the teaching of Klibanov et al. that the purpose of providing
a coating of hydrophilic polymer chains on a liposome is to extend the
blood circulation lifetime of the liposomes. That is, the hydrophilic polymer
shields the liposomes from recognition and uptake by the
reticuloendothelial system (RES) (page 324, lines 19-22). However, the
liposomes of Mihalko et al. are administered by inhalation to the lung
(page 4, lines 16-19 and 24-27). . . .
. . . [T]he liposomes of Mihalko et al. are administered by inhalation to the
lung. The drug is released from the liposomes into the pulmonary region
of the respiratory tract by efflux from the liposome (page 25, lines 9-13)
and only the drug enters the blood for circulation (page 25, lines 17-22).
As the purpose of the liposome with a hydrophilic polymer coating is to
protect the liposome from the RES for longer circulation, one would not be
motivated to modify the liposomes of Mihalko et al. as the liposomes do
not circulate.
Appeal Brief, page 7.
“In rejecting claims under 35 U.S.C. § 103, the examiner bears the initial burden
of presenting a prima facie case of obviousness. ” In re Rijckaert, 9 F.3d 1531, 1532,
28 USPQ2d 1955, 1956 (Fed. Cir. 1993). “[T]o establish obviousness based on a
combination of the elements disclosed in the prior art, there must be some motivation,
suggestion or teaching of the desirability of making the specific combination that was
made by the applicant.” In re Kotzab, 217 F.3d 1365, 1369-70, 55 USPQ2d 1313, 1316
(Fed. Cir. 2000).
We agree with Appellants that the examiner has not adequately explained what
would have led those skilled in the art to combine the references, since Mihalko is
directed to administration of liposomes by inhalation and Klibanov is directed to
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