Ex Parte Wu

Board of Patent Appeals and Interferences

Jun 6, 2011

10176971 (B.P.A.I. Jun. 6, 2011)

MOD PTOL-90A (Rev.06/08)

APPLICATION NO./
CONTROL NO.
FILING DATE FIRST NAMED INVENTOR /
PATENT IN REEXAMINATION
ATTORNEY DOCKET NO.
10/176,971 06/19/2002 Ping Wu

EXAMINER
MUETING, RAASCH & GEBHARDT, P.A.
P.O. BOX 581336
MINNEAPOLIS MN 55458-1336
KOLKER, DANIEL
ART UNIT PAPER NUMBER
1649
MAIL DATE DELIVERY MODE

06/06/2011 PAPER

Please find below and/or attached an Office communication concerning this application or proceeding.

The time period for reply, if any, is set in the attached communication.

UNITED STATES DEPARTMENT OF COMMERCE
U.S. Patent and Trademark Office
Address : COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
UNITED STATES PATENT AND TRADEMARK OFFICE
_____________________________________________________________________________________

UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________

Ex parte PING WU
__________

Appeal 2011-001750
Application 10/176,971
Technology Center 1600
__________

Before ERIC GRIMES, JEFFREY N. FREDMAN, and
STEPHEN WALSH, Administrative Patent Judges.

FREDMAN, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal under 35 U.S.C. § 134 involving claims to producing
cholinergic neurons. The Examiner rejected the claims as obvious. We
have jurisdiction under 35 U.S.C. § 6(b). We affirm.

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Statement of the Case
Background
The Specification teaches a method of “producing neurons by
adhesively culturing neural stem cells and/or progeny thereof in vitro with a
mixture including a mitogenic growth factor, a heparin-like agent and an
extracellular matrix component, and implanting the cultured stem cells
and/or progeny thereof into the mammalian spinal cord or brain, where they
differentiate into neurons” (Spec. 4, ll. 1-6).
The Claims
Claims 5, 7, 9, 11-16, 23, 28, 33, 35, 46-47, 51-58, and 61-69 are on
appeal. 1 Claim 46 is representative and reads as follows:
46. A method of producing cholinergic neurons, the
method comprising:
expanding human neural stem cells and/or progeny
thereof by suspension culture as neurospheres in a serum-
free mixture comprising epidermal growth factor, basic
fibroblast growth factor and leukemia inhibitory factor
(LIF);
adhesively culturing the expanded human neural stem
cells and/or progeny thereof in vitro with a serum-free
mixture comprising basic fibroblast growth factor, heparin,
and an extracellular matrix component; and
implanting the adhesively cultured human neural stem
cells and/or progeny thereof into the mammalian spinal cord
or brain;
wherein the implanted adhesively cultured human
neural stem cells and/or progeny thereof differentiate into
cholinergic neurons.

1 The Examiner withdrew the obviousness rejection over Kalyani,
so claims 17, 18, 59, 60, 70, and 71 are not subject to any rejection
(see Ans. 8).
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The issue
The Examiner rejected claims 5, 7, 9, 11-16, 23, 28, 33, 35, 46-47, 51-
58, and 61-69 under 35 U.S.C. § 103(a) as obvious over Weiss2 and
Carpenter3 (Ans. 3-8).
The Examiner finds that “Weiss teaches methods of proliferating, or
expanding, human neural stem cells, followed by culturing the neural stem
cells as an adhesive culture, and finally implanting the cells or progeny
thereof into the central nervous system of subjects” (Ans. 3). The Examiner
finds “Weiss also discloses that following implantation the cells differentiate
into neurons, including cholinergic neurons” (id. at 3-4).
The Examiner finds that “Carpenter teaches defined, serum-free
medium for use in the proliferation stage, containing EGF and bFGF . . .
Carpenter teaches that inclusion of LIF increases the rate of proliferation”
(id. at 5). The Examiner finds that Carpenter includes heparin in the
medium used to culture adherent cells (id.).
The Examiner finds it obvious “to add LIF, taught by Carpenter to be
effective in increasing the proliferation of neural stem cells, to the defined
medium taught by Weiss” (id. at 6). The Examiner also finds that
“Carpenter teaches that inclusion of heparin is preferred in the
differentiation medium . . . Therefore the step of ‘adhesively culturing’
would have been obvious to one of ordinary skill in the art” (id.).
Appellant contends that it is the “sequential exposure of neural stem
cells to the appropriate growth factors under the specific culture conditions

2 Weiss et al., US 5,750,376, issued May 12, 1998.
3 Carpenter, US 5,968,829, issued Oct. 19, 1999.
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of the claimed method that is critical for generating a specific neuron
subtype, cholinergic neurons” (App. Br. 11). Appellant contends “neither of
Weiss or Carpenter ever provides a demonstration of a method of the
differentiation of implanted human neural stem cells and/or progeny thereof
into cholinergic neurons” (id.).
Appellant “submits that one of ordinary skill in the art would not have
a reasonable expectation of success in combining the teachings of Weiss et
al. and Carpenter to obtain the claimed methods” (id. at 14). Appellant
“submits that the Examiner is using improper hindsight, using the present
specification to pick and choose elements from the cited references.
‘Obviousness cannot be predicated on what is not known at the time an
invention is made, even if the inherency of a certain feature is later
established. (MPEP 2141.02(V). . .)’” (id.).
Appellant “submits that in applying the teachings of Weiss et al., the
Examiner appears to be picking and choosing various steps and conditions
from the multitude of different methods taught by Weiss” (id. at 15).
Appellant contend that combining “the teachings of Weiss et al. and
Carpenter will at most result in the increased in vitro yield of
undifferentiated neuronal stem cells. There is no common sense reason to
combine the cited teachings to obtain the claimed methods” (id. at 16).
The issue with respect to this rejection is: Does the evidence of record
support the Examiner’s conclusion that Weiss and Carpenter render obvious
the method of claim 46?
Findings of Fact
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The following findings of fact (“FF”) are supported by a
preponderance of the evidence of record.
1. The Specification teaches that
transplanted cells differentiate by acquiring cholinergic,
glutamatergic and/or GABAergic phenotypes in a region-
specific manner. For example, when transplanted into
medial septum or spinal cord, they preferentially
differentiate into cholinergic neurons; when transplanted
into frontal cortex they preferentially differentiate into
glutamatergic neurons; and when transplanted into
hippocampus they preferentially differentiate into
GABAergic neurons.

(Spec. 15, ll. 19-24.)
2. Weiss teaches that “a preferred embodiment for proliferation of
neural stem cells is to use a defined, serum-free culture medium, as serum
tends to induce differentiation and contains unknown components” (Weiss,
col. 16, ll. 35-38).
3. Weiss teaches that a “particularly preferable culture medium is
a defined culture medium comprising a mixture of DMEM, F12, and a
defined hormone and salt mixture” (Weiss, col. 16, ll. 40-42).
4. Weiss teaches that “culture medium is supplemented with at
least one proliferation-inducing growth factor. . . . Preferred proliferation-
inducing growth factors include EGF . . . [and] basic fibroblast growth factor
(bFGF or FGF-2)” (Weiss, col. 16, ll. 53-65).
5. Weiss teaches that “[w]ithin 3-4 days in the presence of a
proliferation-inducing growth factor, a multipotent neural stem cell begins to
divide giving rise to a cluster of undifferentiated cells referred to herein as a
‘neurosphere’” (Weiss, col. 17, ll. 17-20).
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6. Weiss teaches that the “neurospheres of the suspension culture
can be easily passaged to reinitiate proliferation” (Weiss, col. 17, ll. 51-52).
7. Weiss teaches that “[d]ifferentiation can also be induced by
plating the cells on a fixed substrate such as flasks, plates, or coverslips
coated with an ionically charged surface such as poly-L-lysine” (Weiss, col.
18, ll. 51-55).
8. Weiss teaches that other “substrates may be used to induce
differentiation such as . . . laminin” (Weiss, col. 18, ll. 56-57).
9. Weiss teaches that among “the growth factors and other
molecules that can be used to influence the differentiation of precursor cells
in vitro are . . . FGF-2” (Weiss, col. 20, ll. 45-47).
10. Weiss teaches that the
progeny of multipotent neural stem cells obtainable from
embryonic or adult CNS tissue, which are able to divide
indefinitely when maintained in vitro using the culture
conditions described herein, meet all of the desirable
requirements of cells suitable for neural transplantation
purposes and are a particularly suitable cell line as the cells
have not been immortalized and are not of tumorigenic
origin. The use of multipotent neural stem cells in the
treatment of neurological disorders and CNS damage can be
demonstrated by the use of animal models.

(Weiss, col. 23, ll. 27-36.)
11. Weiss teaches that “[s]tandard stereotactic neurosurgical
methods are used to inject cell suspensions both into the brain and spinal
cord” (Weiss, col. 25, ll. 58-60).
12. Carpenter teaches that “neural stem cells have been cultured in
serum-free media containing epidermal growth factor (‘EGF’) . . . as the
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mitogen for proliferation. . . . Further, basic fibroblast growth factor
(‘bFGF’) has been used, either alone, or in combination with EGF, to
enhance long term neural stem cell survival” (Carpenter, col. 2, ll. 60-67).
13. Carpenter teaches that the “improved medium according to this
invention, which contains leukemia inhibitory factor (‘LIF’), markedly and
unexpectedly increases the rate of proliferation of neural stem cells,
particularly human neural stem cells” (Carpenter, col. 3, ll. 1-4).
14. Carpenter teaches that it “is also advantageous to provide
heparin in the culture medium” (Carpenter, col. 3, ll. 38-39).
15. Carpenter teaches that “this invention provides a differentiated
cell culture containing previously unobtainable large numbers of neurons . . .
we have routinely achieved neuron concentrations of between 20% and 35%
(and much higher in other cases) in differentiated human forebrain-derived
neural stem cell cultures” (Carpenter, col. 4, ll. 18-27).
16. Carpenter teaches that “we have achieved differentiated neural
stem cell cultures that are highly enriched in GABA-ergic neurons. Such
GABA-ergic neuron enriched cell cultures are particularly advantageous in
the potential therapy of excitotoxic neurodegenerative disorders” (Carpenter,
col. 4, ll. 31-36).
17. Carpenter teaches that “[c]holinergic neurons may be identified
by their production of choline acetyltransferase (‘ChAT’)” (Carpenter, col.
5, ll. 2-4).
18. Carpenter teaches
methods for differentiating neural stem cells to yield cell
cultures enriched with neurons to a degree previously
unobtainable. According to one protocol, the proliferating
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neurospheres are induced to differentiate by removal of the
growth factor mitogens and LIF, and provision of 1% serum,
a substrate and a source of ionic charges (e.g., glass cover
slip covered with poly-ornithine or extracellular matrix
components). The preferred base medium for this
differentiation protocol, excepting the growth factor
mitogens and LIF, is otherwise the same as the proliferation
medium. This differentiation protocol produces a cell culture
enriched in neurons. According to this protocol, we have
routinely achieved neuron concentrations of between 20%
and 35% in differentiated human forebrain-derived neural
stem cell cultures.

(Carpenter, col. 5, ll. 49-63.)
19. Carpenter teaches that “[w]e also contemplate use of the cells of
this invention in the treatment of various acute and chronic pains, as well as
for certain nerve regeneration applications (such as spinal cord injury)”
(Carpenter, col. 7, ll. 48-51).
Principles of Law
“The combination of familiar elements according to known methods
is likely to be obvious when it does no more than yield predictable results.”
KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 416 (2007).
Analysis
Weiss teaches a method of expanding human neural stem cells in
suspension culture as neurospheres in serum free medium with epidermal
growth factor and basic fibroblast growth factor (FF 2-6). Weiss teaches
that the expanded cells can be cultured on a solid support with basic
fibroblast growth factor and the extracellular matrix component, laminin (FF
7-9). Weiss teaches implanting the cultured cells into brain and spinal cord
(FF 10-11).
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The Examiner acknowledges that Weiss does not teach inclusion of
LIF in the proliferation medium or heparin in the differentiation medium
(Ans. 5).
Carpenter also teaches culture of neural stem cells (FF 12). Carpenter
specifically teaches that the “improved medium according to this invention,
which contains leukemia inhibitory factor (‘LIF’), markedly and
unexpectedly increases the rate of proliferation of neural stem cells,
particularly human neural stem cells” (Carpenter, col. 3, ll. 1-4; FF 13).
Carpenter teaches that for the differentiation medium, it “is also
advantageous to provide heparin in the culture medium” (Carpenter, col. 3,
ll. 38-39; FF 14). Carpenter teaches that the use of LIF in the proliferation
medium followed by heparin in the differentiation medium results in large
numbers of neurons (FF 18), which Carpenter teaches may be applied to
spinal cord injury (FF 19).
Applying the KSR standard of obviousness to the findings of fact, we
conclude that an ordinary artisan would have reasonably found it obvious to
incorporate LIF into the proliferation medium of Weiss since Carpenter
teaches this increases the rate of proliferation of stem cells (FF 13). We also
find that the ordinary artisan would have incorporated heparin into the
differentiation medium of Weiss since Carpenter teaches that this is
advantageous (FF 14). Such a combination is merely a “predictable use of
prior art elements according to their established functions.” KSR, 550 U.S. at
417.
Appellant contends that it is the “sequential exposure of neural stem
cells to the appropriate growth factors under the specific culture conditions
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of the claimed method that is critical for generating a specific neuron
subtype, cholinergic neurons” (App. Br. 11). Appellant contends “neither of
Weiss or Carpenter ever provides a demonstration of a method of the
differentiation of implanted human neural stem cells and/or progeny thereof
into cholinergic neurons” (id.).
We are not persuaded on this point for several reasons. It is solely
attorney argument that sequential exposure is “critical.” In re Pearson, 494
F.2d 1399, 1405 (CCPA 1974). The Wu Declaration4 states that
adhesively culturing human neural stem cells and/or progeny
thereof in vitro with a mixture comprising a mitogenic
growth factor, a heparin-like agent, and an extracellular
matrix component, all at defined concentrations, and
implanting neural stem cells and/or progeny thereof primed
in such a fashion into the mammalian spinal cord or brain
effectively results in the differentiation of cholinergic
neurons.

(Wu Dec. 5 ¶ 15.) Thus, Dr. Wu does not indicate that particular growth
factors, heparin-like agents or matrix components are critical for priming.
This lack of criticality is also consistent with Appellant’s
Specification, which states that
transplanted cells differentiate by acquiring cholinergic,
glutamatergic and/or GABAergic phenotypes in a region-
specific manner. For example, when transplanted into
medial septum or spinal cord, they preferentially
differentiate into cholinergic neurons; when transplanted
into frontal cortex they preferentially differentiate into
glutamatergic neurons; and when transplanted into

4 Declaration of Dr. Ping Wu, filed May 8, 2006.
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hippocampus they preferentially differentiate into
GABAergic neurons.

(Spec. 15, ll. 19-24; FF 1.) Thus, the Specification disputes Appellant’s
“critical” sequential exposure argument, by indicating that neural cells
transplanted into spinal cord preferentially differentiate into cholinergic
neurons (FF 1). We therefore agree with the Examiner that “once the cells
are cultured in the two different media and implanted, they will necessarily
differentiate into cholinergic neurons” (Ans. 9). See In re Best, 562 F.2d
1252, 1255 (CCPA 1977) (“Where, as here, the claimed and prior art
products are identical or substantially identical, or are produced by identical
or substantially identical processes, the PTO can require an applicant to
prove that the prior art products do not necessarily or inherently possess the
characteristics of his claimed product.”).
Appellant “submits that one of ordinary skill in the art would not have
a reasonable expectation of success in combining the teachings of Weiss et
al. and Carpenter to obtain the claimed methods” (App. Br. 14). Appellant
“submits that the Examiner is using improper hindsight, using the present
specification to pick and choose elements from the cited references.
‘Obviousness cannot be predicated on what is not known at the time an
invention is made, even if the inherency of a certain feature is later
established. (MPEP 2141.02(V) . . .)’” (id.). Appellant “submits that in
applying the teachings of Weiss et al., the Examiner appears to be picking
and choosing various steps and conditions from the multitude of different
methods taught by Weiss” (id. at 15).
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We are not persuaded. The use of LIF and heparin do not result from
“picking and choosing” but rather from the direct suggestion and teaching of
Carpenter. That is, Carpenter teaches that LIF “markedly and unexpectedly
increases the rate of proliferation of neural stem cells, particularly human
neural stem cells” (Carpenter, col. 3, ll. 1-4; FF 13). Carpenter also teaches,
for the adherent medium, that it “is also advantageous to provide heparin in
the culture medium” (Carpenter, col. 3, ll. 38-39; FF 14). The express
suggestion of Carpenter not only provides reasons to incorporate LIF and
heparin into the protocol of Weiss, but provides a reasonable expectation of
success, since Carpenter teaches that the addition of LIF enhances the
proliferation rate of neural stem cells (FF 13). Kubin stated that
“[R]esponding to concerns about uncertainty in the prior art influencing the
purported success of the claimed combination, this court [in O’Farrell]
stated: ‘[o]bviousness does not require absolute predictability of success …
all that is required is a reasonable expectation of success.”’ In re Kubin, 561
F.3d 1351, 1360 (Fed. Cir. 2009) (citing In re O’Farrell, 853 F.2d 894, 903-
904 (Fed. Cir. 1988)). Appellant has provided no evidence to rebut the very
reasonable expectation of success that would be expected based upon the
teachings of Carpenter (FF 13-18).
Appellant contends that combining “the teachings of Weiss et al. and
Carpenter will at most result in the increased in vitro yield of
undifferentiated neuronal stem cells. There is no common sense reason to
combine the cited teachings to obtain the claimed methods” (App. Br. 16).
We are not persuaded. Both Weiss and Carpenter teach and suggest
the transplantation of the neural stem cells into the brain and spinal cord (FF
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11, 19). Carpenter specifically teaches identification of cholinergic cells (FF
17). Upon combining the methods, and treating brain or spinal cord with
the neural stem cells suggested by Weiss and Carpenter, the Examiner
reasonably concludes that some neural stem cells will necessarily
differentiate into cholinergic neural cells (Ans. 6). Not only has Appellant
not shown otherwise (Best, 562 F.2d at 1255), but the Wu Declaration taught
that even in the unprimed graft group “only a few differentiated into
cholinergic neurons” (Wu 4 ¶ 11). However, these few cells would
reasonably satisfy the requirements of claim 46, which simply requires that
some of the implanted human neural stem cells differentiate into cholinergic
neurons (see Claim 46).
Thus, it is reasonable to conclude that neural stem cells primed as
taught and suggested by Weiss and Carpenter (FF 2-19), implanted into
brain or spinal cord environments which necessarily result in differentiation
into cholinergic neurons (FF 1), would inherently differentiate into
cholinergic neurons.
Conclusion of Law
The evidence of record supports the Examiner’s conclusion that Weiss
and Carpenter render obvious the method of claim 46.
SUMMARY
In summary, we affirm the rejection of claim 46 under 35 U.S.C. §
103(a) as obvious over Weiss and Carpenter. Pursuant to 37 C.F.R. §
41.37(c)(1)(vii)(2006), we also affirm the rejection of claims 5, 7, 9, 11-16,
23, 28, 33, 35, 47, 51-58, and 61-69, as these claims were not argued
separately.
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No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(1).

AFFIRMED

JNF
SW
EG

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