Appeal No. 1996-1273
Application 07/956,003
cites appellants’ argument that Russell-Jones “teaches the covalent coupling of [the] B molecule to a
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drug and not a microsphere encapsulating a drug” and in response thereto takes the “position that B is
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a targeting molecule recognizing intrinsic factor just as the targeting molecules recognizing specific
targets taught by the cited prior art and thus, it would be obvious to an artisan to use B as a targeting
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molecule with the expectation of obtaining similar results” (answer, page 8). Indeed, appellants point
out, inter alia, that Russell-Jones “uses a vitamin B molecule to transport only one active substance
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molecule per oral administration” and further contend, inter alia, that “nowhere is it taught or suggested
that a vitamin B –microparticle/active ingredient complex would be effective” in submitting that the only
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suggestion to combine the cited prior art is taken from their own disclosure (principal brief, page 13,
see also principal brief, pages 11-12 and 13-14). We agree with appellants.
There is agreement that Russell-Jones is the sole reference of record which teaches the use of
Vitamin B as a carrier to which a single drug is covalently bonded to form a drug delivery system.
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This reference contains the following disclosure in discussing the invention taught therein in the context
of the prior art:
Recent work by us utilizing a number of molecules with the ability to bind to the intestinal
mucosa has demonstrated effective oral immunization using low doses of these binding
proteins or by coupling various antigens or haptens to these carriers. Uptake and delivery to
the circulation of these molecules from the intestine seemed to be due to receptor mediated
endocytosis.
It has been known for some time that a number of specific uptake mechanisms exist in the
gut for uptake of dietary molecules. Thus there are specific uptake mechanisms for
monosaccharides, disaccharides, amino acids and vitamins. Most of these uptake mechanisms
depend upon the presence of a specific protein or enzyme such as monosaccharidase or
diaccharidase situated in the mucosal lamina propria which binds to the molecule and
transports it into the cells lining and [sic] lamina propria.
Two notable exceptions to these uptake mechanisms are found with iron transport and
VB12 uptake. In both these cases a specific binding protein is released into the intestine,
which binds to its ligand in the lumen of the gut.
. . . .
Similarly, the absorption of physiological amounts of VB12 by the gut requires that it be
complexed with a naturally occurring transport protein known as intrinsic factor (IF) . . . . This
protein is released into the lumen of the stomach by parietal cells in the fundus. Once bound
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