Appeal No. 1997-2634
Application 08/222,662
According to the examiner, Elia “meets the claim language except for the type of
poly(phosphazene) as claimed . . . [h]owever, [Laurencin] teaches that the claimed
phosphazene has been known to the art as a skeletal tissue regeneration material.” The
examiner concludes that “it would have been obvious to use the polyphosphazene material
of [Laurencin] . . . as the polyphosphazene material of [Elia] in order to promote ingrowth
and in order to bring the controllable set of properties of hydrolytic stability and
bioacceptability to the [Elia] invention.” Examiner’s Answer, page 4.
Appellants argue essentially that “[t]he device of Elia is a container to put bone
material in,” e.g., hydroxyapatite, while Laurencin merely “discloses osteoblast-like cell
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growth on non-porous two-dimensional erodible systems.” In contrast, “the claimed
composition is a biodegradable matrix which serves as a temporary scaffold for the
regeneration of skeletal tissue . . . formed from a polyphosphazene polymer which has
been processed to form pores which the cells can migrate into and proliferate within,” in
other words, “the claimed porous structure allows for sufficient space to promote cell
fixation and growth,” enabling “bone actually to be replaced in whole or in part as opposed
to merely providing a surface for growth or containment.” If we understand appellants’
argument correctly, it is that, unlike the situation in Elia, osteoblasts actually invade the
5The examiner does not address the issue of porosity in the statement of the
rejection, except to cite column 13 of Elia. In responding to appellants’ arguments
regarding the porosity of the claimed devices, the examiner concedes that Laurencin does
not disclose a porous polyphosphazene polymer, and again cites column 13, specifically
lines 35-63, of Elia (which mentions a pore sizes of 25 to 400 microns). Examiner’s
Answer, pages 4, 6 and 7.
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