Ex Parte Berg

Board of Patent Appeals and Interferences

Feb 6, 2003

09155995 (B.P.A.I. Feb. 6, 2003)

The opinion in support of the decision being entered today was not written
for publication and is not binding precedent of the Board.
Paper No. 22
UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
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Ex parte HANS BERG
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Appeal No. 2002-0456
Application No. 09/155,995
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HEARD October 24, 2002
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Before SCHEINER, ADAMS and GREEN, Administrative Patent Judges.
SCHEINER, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on appeal under 35 U.S.C. § 134 from the final rejection of
claims 1-20, all the claims remaining in the application. Claims 1 and 11 are
representative of the subject matter on appeal and read as follows:
1. A process for the production of a porous cross-linked polysaccharide gel,
comprising the following steps:
a) preparing a solution or dispersion of the polysaccharide,
b) adding a bifunctional cross-linking agent having one active site and one
inactive site to the solution or dispersion from step a),
c) reacting hydroxylgroups of the polysaccharide with the active site of the cross-
linking agent,
d) forming a polysaccharide gel,
e) activating the inactive site of the cross-linking agent,
f) reacting the activated site from step e) with hydroxylgroups of the
polysaccharide gel, whereby cross-linking of the gel takes place.
Appeal No. 2002-0456
Application No. 09/155,995
Page 2
1 U.S. Patent No. 4,973,683 to Lindgen, issued November 27, 1990.
11. A porous, cross-linked polysaccharide gel obtainable by the following steps:
a) preparing a solution or dispersion of the polysaccharide,
b) adding a bifunctional cross-linking agent having one active site and one
inactive site to the solution or dispersion from step a),
c) reacting hydroxylgroups of the polysaccharide with the active site of the cross-
linking agent,
d) forming a polysaccharide gel,
e) activating the inactive site of the cross-linking agent,
f) reacting the activated site from step e) with hydroxylgroups of the
polysaccharide gel, whereby cross-linking of the gel takes place.
Claims 1-20 stand rejected under 35 U.S.C. § 103 as unpatentable over
Lindgren1 alone, and over Lindgren “in view of appellant’s own admissions.” Examiner’s
answer, pages 3-6.
We reverse both of these rejections.
BACKGROUND
“Gel matrices of polysaccharides have long been used as separation media . . .
[in] chromatographic separation methods.” Specification, page 1. As further explained
in the specification (pages 1-2):
Generally, chromatographic separations are carried out in columns
packed with the separation matrix in [the] form of particulate beads.
Separation media of a fast kinetics with rapid flow rates results in a high
productivity and may be achieved by a reduction in the particle size.
However, small beads result in a higher back pressure due to the
narrowing of the convective flow channels between the particles in a
packed bed. To be able to separate large molecules the particles should
have large pores, but large pores may result in a weakened structure of
the particles. As the polysaccharides are soft materials the particles may
easily collapse, especially at high flow rates . . . It is well known to
increase the stability of polysaccharide particles by cross-linking the
polymer . . . [stabilizing] the polysaccharide gel matrices by chemically
binding the polymer chains with each other at their respective free
hydroxyl groups. The cross-linking takes place between the hydroxyl and
the functional groups of the cross-linkers. This affects the particle rigidity,
but to a lesser extent or not at all the size of the pores . . .
Appeal No. 2002-0456
Application No. 09/155,995
Page 3
[Additionally,] it was found that the rigidity of the polysaccharides was
considerably improved when the cross-linking agent used was
monofunctional but also contained an additional masked functional group
that could be activated later. The cross-linking was made in two steps.
First the polysaccharide was derivatized with the monofunctional group.
Then, in the next step the masked group was activated and made to react
with the hydroxyl groups of the polysaccharide.

According to appellant, “the state of the art [ ] is that the cross-linking is made on
the polysaccharide polymer after the formation of the gel . . . [t]hus, the cross-linking is
made on the ready made structure.” Specification, page 2. The present invention, on
the other hand, is directed to cross-linked polysaccharide gels, and methods of making
them, in which a bifunctional cross-linking agent “is introduced into the polysaccharide
solution or dispersion before the gel formation . . . the active site of the [bifunctional
cross-linking] agent is allowed to react with the hydroxyl groups of the polysaccharide”
and “thereby . . . is chemically bound to the polymer chains before the gel formation
process is started.” Id., page 4. “In this manner an internal cross-linking agent is
introduced into the polysaccharide,” resulting in cross-linked polysaccharide gels “with
improved capability to withstand high flow rates/back pressures, but with retained
separation qualities.” Id., page 3.
DISCUSSION
According to the examiner, Lindgren “discloses the essential details of the instant
process . . . [and] is directed to the same subject matter” except for “the use of an
organic solvent in the gelling[ ] process step.” Answer, page 4. Based on his findings,
the examiner concludes that “[t]he disclosure in [Lindgren] . . . is deemed to render the
instant claimed compound produced and the instant claimed process lacking in
patentable distinction in the absence of unexpected results.” Id.
Appeal No. 2002-0456
Application No. 09/155,995
Page 4
Findings of fact underlying an obviousness rejection, as well as conclusions of
law, must be made in accordance with the Administrative Procedure Act, 5 U.S.C. 706
(A),(E) (1994), see Zurko v. Dickinson, 527 U.S. 150, 158, 119 S.Ct. 1816, 1821, 50
USPQ2d 1930, 1934 (1999), and must be supported by substantial evidence within the
record. See In re Gartside, 203 F.3d 1305, 1315, 53 USPQ2d 1769, 1775 (Fed. Cir.
2000). In addition, in order for meaningful appellate review to occur, the examiner must
present a full and reasoned explanation of the rejection. See, e.g., In re Lee, 277 F.3d
1338, 1342, 61 USPQ2d 1430, 1432 (Fed. Cir. 2002). We would further emphasize
what should be self-evident: the examiner must present a full and reasoned explanation
of the rejection in the statement of the rejection, specifically identifying underlying facts
and any supporting evidence, in order for appellants to have a meaningful opportunity
to respond.
The claimed process requires the addition of a “bifunctional” cross-linking agent
to a polysaccharide solution or suspension before the polysaccharides are allowed or
induced to form a gel. The bifunctional cross-linking agent must have one active site
which reacts with - and substitutes - the polysaccharides before gel formation, and
another site, initially inactive, that is activated (and allowed to react with and cross-link
the polysaccharides) after gel formation. Having failed to address this aspect of the
invention in the first instance, the examiner belatedly argues that “inspection of
Example 1 of [Lindgren] suggests that the process of the cited reference also does not
produce a gel until after the [substitution] portion of the process has been completed.”
Nevertheless, Lindgren, at columns 3 and 4, describes a generic process
whereby pre-formed polysaccharide gels are substituted and cross-linked with
bifunctional cross-linking agents. Example 1, which immediately follows, describes the
Appeal No. 2002-0456
Application No. 09/155,995
Page 5
results of cross-linking Sepharose ® with allylbromide. According to the examiner’s
argument, then, the Sepharose ® used in the example is not a gel. As this would be
inconsistent with Lindgren’s generic description of the prior art process (not to mention
Examples 2 through 6), and as the examiner has provided no factual basis for his
assertion, we are not persuaded by this argument. Similarly, the examiner has not
established a factual basis for his assertion that “the product produced by the prior art
method is . . . patentably indistinguishable from the instant claimed product” (Answer,
page 4).
Finally, we are at a loss as to how the examiner can interpret “[a]ppellant’s
admission . . . that the contacting of agarose or other polysacharides with crosslinking
agents is conventional in the art” as “an admission that . . . the appropriate conditions
for their use are not a patentably distinguishing feature.” Answer, page 6.
The initial burden of presenting a prima facie case of obviousness rests on the
examiner. In re Oetiker, 977 F.2d 1443, 1445, 24 USPQ2d 1443, 1444 (Fed. Cir.
1992). Thus, the examiner is charged with adequately addressing every limitation of
the claimed invention. This the examiner has not done. In our judgment, Lindgren’s
disclosure, with or without “appellant’s admission,” is insufficient to support a
conclusion of obviousness of claims containing the limitations discussed above and the
examiner has failed to provide an adequate factual basis to establish a prima facie case
of obviousness within the meaning of 35 U.S.C. § 103.
Appeal No. 2002-0456
Application No. 09/155,995
Page 6
On this record, we reverse both of the examiner’s rejections of the claims on
appeal.
REVERSED
)
Toni R. Scheiner )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
)
Donald E. Adams ) APPEALS AND
Administrative Patent Judge )
) INTERFERENCES
)
)
)
Lora M. Green )
Administrative Patent Judge )
Appeal No. 2002-0456
Application No. 09/155,995
Page 7
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