Ex Parte Keller et al

Patent Trial and Appeal Board

Feb 16, 2018

12410782 (P.T.A.B. Feb. 16, 2018)

United States Patent and Trademark Office
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O.Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
12/410,782 03/25/2009 Gordon Keller 84284.00031 3906
125087 7590 02/21/2018
Foy RnthsohilH T T P / Mount Sinai
EXAMINER
997 Lenox Drive, Building 3
Lawrenceville, NJ 08648-2311
SINGH, ANOOP KUMAR
ART UNIT PAPER NUMBER
1632
NOTIFICATION DATE DELIVERY MODE
02/21/2018 ELECTRONIC
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.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
ipdocket @ foxrothschild. com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte GORDON KELLER, LEI YANG, and
STEVEN KATTMAN1
Appeal 2017-001461
Application 12/410,782
Technology Center 1600
Before ERIC B. GRIMES, FRANCISCO C. PRATS, and
JOHN E. SCHNEIDER, Administrative Patent Judges.
GRIMES, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal under 35U.S.C. § 134 involving claims to human
cardiovascular progenitor cells, which have been rejected as being directed
to patent-ineligible subject matter and as obvious. We have jurisdiction
under 35 U.S.C. § 6(b).
We reverse.
STATEMENT OF THE CASE
Claims 1, 3—5, and 39 are on appeal. Claim 1 is the only independent
claim and reads as follows:
1 Appellants identify the Real Party in Interest as Icahn School of Medicine
at Mount Sinai. (Appeal Br. 3.)
Appeal 2017-001461
Application 12/410,782
1. An isolated population of human cardiovascular progenitor
cells derived from human pluripotent stem cells in vitro,
wherein the progenitor cells express KDR and do not express
C-KIT and VE-CADHERIN and wherein the progenitor cells
are progenitors of cardiomyocytes, endothelial cells, and
vascular smooth muscle cells.
The claims stand rejected as follows:
Claims 1, 3—5, and 39 under 35 U.S.C. § 101 on the basis that they are
directed to patent-ineligible subject matter; specifically, a product of nature
(Ans. 2) and
Claims 1, 3—5, and 39 under 35 U.S.C. § 103(a) as obvious based on
Kattman,2 Keller,3 and Gouon-Evans4 (Ans. 7—8).
I
The Examiner has rejected all of the claims on appeal under 35 U.S.C.
§ 101 as being directed to a product of nature. The Examiner finds that the
Specification discloses human embryonic stem (hES) cells as the starting
material for the claimed cell population and that the art teaches that hES
cells occur naturally in the inner cell mass (ICM) of human blastocysts.
(Ans. 3—4.) The Examiner reasons that
[t]he claimed invention is merely a cell culture comprising
naturally occurring components in a closed, sterile system that
2 Kattman et al., Multipotent Flk-1+ Cardiovascular Progenitor Cells Give
Rise to the Cardiomyocyte, Endothelial, and Vascular Smooth Muscle
Lineages, 11 Developmental Cell 723-732 (2006).
3 Keller et al., US 2010/0158872 Al, pub. June 24, 2010.
4 Gouon-Evans et al., BMP-4 is required for hepatic specification of mouse
embryonic stem cell-derived definitive endoderm, 25 Nature
Biotechnology 1402-11 (2006).
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Application 12/410,782
was routine in art. While it is obvious that in vitro cell cultures
do not naturally occur, the combination of the constituent culture
parts do in fact occur in nature and as taught above are known to
occur as a common Flk-1+ (kinase insert domain protein receptor,
also known as KDR) cardiovascular progenitor that represents
one of the earliest stages in mesoderm specification to the
cardiovascular lineages. Thus the claimed invention is
interpreted to comprise an isolated system of cells and
components/factors that would naturally occur in nature
together.
(Id. at 5, citations omitted.) The Examiner cites the Kattman and Keller
references relied on in the § 103 rejection, as well as Laflamme5 and Yang6
as evidence supporting this conclusion.
The Examiner concludes that
[tjhere is no structural difference between the isolated flk+
human cardiovascular progenitor cells in the claim and the
naturally occurring cells that are one of the earliest stages of
human cardiac development.... [Ajpplicant has not changed the
cells in any way, but instead has simply selected and
characterized the earliest stages in mesoderm specification in
naturally occurring human ES cells. Because the population of
human cardiovascular progenitor cells is structurally identical to
naturally occurring cells, they are not markedly different.
(Id. at 6—7.) Finally, the Examiner concludes that “[t]he claim is to a
‘product of nature’ exception with nothing that adds significantly more.”
(Id. at 7.)
5 Laflamme et al., Cardiomyocytes derived from human embryonic stem
cells in pro-survival factors enhance function of infarcted rat hearts,
Nature Biotechnology 1-10 (published online Aug. 22, 2007).
6 Yang et al., Human cardiovascular progenitor cells develop from a KDR+
embryonic-stem-cell-derived population, 453 Nature 524—529 (2008).
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Application 12/410,782
Appellants argue that “[t]he claims are not directed to a nature-based
product because cells differentiated from pluripotent stem cells in vitro are
necessarily different than cells found in nature.” (Appeal Br. 9.) Appellants
reason that
the pluripotent cells are cultured in media supplemented with
growth factors and compounds that attempt to create what the
inventors believe to be the natural differentiation process.
However, these differentiation processes cannot perfectly
replicate what is found in nature, and the resulting differentiated
cells are thus necessarily different than cells found in nature.
(Id.) Appellants cite Vidarsson7 and van den Heuvel8 as evidence
supporting their position. (Id. at 10.)
[T]he examiner bears the initial burden, on review of the prior art
or on any other ground, of presenting a prima facie case of
unpatentability. If that burden is met, the burden of coming
forward with evidence or argument shifts to the applicant. After
evidence or argument is submitted by the applicant in response,
patentability is determined on the totality of the record, by a
preponderance of evidence with due consideration to
persuasiveness of argument.
In re Oetiker, 977 F.2d 1443, 1445 (Fed. Cir. 1992).
We agree with Appellants that the Examiner has not shown, by a
preponderance of the evidence of record, that the claimed cell population is a
naturally occurring product. Vidarsson states that
7 Vidarsson et al., Differentiation of Human Embryonic Stem Cells to
Cardiomyocytes for In Vitro and In Vivo Applications, 6 Stem Cell. Rev.
and Rep. 108-120 (2010).
8 Van den Heuvel et al., Lessons from the heart: Mirroring
electrophysiological characteristics during cardiac development to in vitro
differentiation of stem cell derived cardiomyocytes, 61 J. Mol. Cell.
Cardiology 12-25 (2014).
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Application 12/410,782
the stem cell derived cardiomyocytes described to date, generally
resemble immature embryonic/fetal cardiomyocytes, and they
are in some functional and structural aspects different from adult
cardiomyocytes. . . . Nevertheless, the cells which can be
prepared using current protocols still have wide spread utility,
and they have begun to find their way into the drug discovery
platforms.
(Vidarsson 108, abstract.) Similarly, Vidarsson states that “electron
microscopy analysis of hESC-derived cardiomyocytes demonstrated that. . .
the cells displayed functional properties characteristic of human fetal
cardiomyocytes.” {Id. at 113, left col.)
Vidarsson states that “hESC-derived cardiomyocytes were reported to
respond in the opposite manner” from mature myocytes in response to
increased stimulation, and “the regulation of intracellular calcium handling
has also been shown to differ between hESC-derived-and adult
cardiomyocytes.” {Id. at 113, right col.) Finally, Vidarsson states that “stem
cell derived cardiomyocytes display electrophysiological properties similar
to developing embryonic/fetal cardiomyocytes.” {Id. at 114, right col.)
Thus, while Vidarsson provides evidence that cardiac cells derived
from hES cells “resemble” or “are similar to” embryonic/fetal
cardiomyocytes, it does not state that the hES-derived cells are the same as
naturally occurring cells.
Van den Heuvel also states that “the phenotype and functionality of
hPSC-CM [human pluripotent stem cell-derived cardiomyocytes] more
closely resembles that of a fetal than an adult CM.” (Van den Heuvel 13,
right col.) Van den Heuvel states that “[ojbviously, part of the difference
between the hESC-derived CMs and the fetal and adult heart depends on the
presence of other cell types in the latter, such as smooth muscle cells and
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endothelial cells (blood vessels), but this will not explain the complete
difference.” (Id. at 20, right col.) Thus, van den Heuvel provides evidence
that there is a difference between hES cell-derived cardiomyocytes and cells
of both “the fetal and adult heart.” (Id. )
In summary, both Vidarsson and van den Heuvel support Appellants’
position that cardiac progenitor cells derived from hES cells by in vitro
culturing differ from their naturally occurring counterparts.
In response to Appellants’ reliance of Vidarsson and van den Heuvel,
the Examiner cites Yang’s statement that
a recent study has reported the identification of a C-KIT+KDR-
cardiac stem cell in the adult human heart that also displays the
capacity to generate myocytes, smooth muscle cells and
endothelial cells. The differences in surface markers between the
two populations may reflect the fact that one represents an early
embryonic stage of development (as claimed in the instant
application) whereas the other is derived from the adult heart.
(Ans. 12, quoting Yang 527, right col.)
We agree with the Examiner that Yang’s statements provide evidence
favoring the Examiner’s position. Yang states, for example, that
after induction with combinations of activin A, bone
morphogenetic protein 4 (BMP4), basic fibroblast growth factor
(bFGF, also known as FGF2), vascular endothelial growth factor
(VEGF, also known as VEGFA) and dickkopf homolog 1
(DKK1) in serum-free media, human embryonic-stem-cell-
derived embryoid bodies generate a KDRlow/C-KIT (CD117)neg
population that displays cardiac, endothelial and vascular smooth
muscle potential. . . . Together, these findings identify a human
cardiovascular progenitor that defines one of the earliest stages
of human cardiac development.
(Yang 524, left col.)
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That statement, however, must be balanced with the rest of the
evidence supporting the positions of both the Examiner and Appellants.
Here, both Vidarsson and van den Heuvel provide evidence that
cardiomyocytes derived from hES cells in vitro differ from cardiomyocytes
in a developing embryo because they do not mature into cardiomyocytes that
have the same properties as adult cardiomyocytes, as naturally occurring
cells in a developing embryo do. Importantly, van den Heuvel demonstrates
that, even in cardiac progenitor cells that have not developed into
cardiomyocytes, cells found in vivo differ from those derived from hES cells
in vitro.
Specifically, van den Heuvel’s Figure 2 shows a comparison of in
vivo development of human fetal heart with in vitro differentiation of human
pluripotent stem cells. (Van den Heuvel 14.) The figure shows that at the
cardiac progenitor cell stage of in vivo heart development, cells express the
following signaling pathways and transcription factors: Nkx2-5, Tbx5,
GATA-4, GATA-5, GATA-6, and Mef2C. (Van den Heuvel, Figure 2, left
side.) The figure also shows that at the same stage of in vitro heart
development, cells express the following signaling pathways and
transcription factors: Isll, Nkx2-5, Tbx5/20, GATA-4, and Mef2C, and the
surface marker SIRPA. (Van den Heuvel, Figure 2, right side.)
Thus, van den Heuvel discloses that cells in vivo express GATA-5
and GATA-6, which are not expressed during in vitro differentiation, while
cells in vitro express Isll and the surface marker SIRPA. Van den Heuvel
therefore supports Appellants’ position that cardiac progenitor cells
differentiated in vitro differ from those found in vivo.
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Considering the evidence of record as a whole, we conclude that the
rejection under 35 U.S.C. § 101 is not supported by a preponderance of the
evidence. We therefore reverse the rejection of claims 1, 3—5, and 39 as
being directed to patent-ineligible subject matter.
II
The Examiner has rejected all of the claims on appeal as obvious
based on Kattman, Keller, and Gouon-Evans. The Examiner finds that
“Kattman et al teach a method of generating FLK+(KDR) mouse
cardiovascular progenitor cells containing cardiomyocyte, endothelial and
vascular smooth muscle cells . . . comprising culturing cardiovascular
precursor cells in presence of VEGF, BMP-4 and an inhibitor of Wnt that is
DKK-1,” but Kattman does not teach human cardiovascular progenitor cells.
(Ans. 8.)
The Examiner finds that Keller teaches a population of human cardiac
progenitor cells derived from hES cells, where the progenitor cells express
KDR and are progenitor cells for cardiomyocyte, endothelial and vascular
smooth muscle cells. (Id.) The Examiner finds that “Gouon-Evans provide
motivation to characterize the cardiac progenitor cells for C-KIT expression
as its expression in mouse embryoid bodies identified the earliest
hemangioblast-derived haematopoietic and vascular progenitors.” (Id.)
The Examiner concludes that it would have been obvious “to combine
the method of Kattman and Gouon-Evans to isolate human Flk-l+c-kit-
and/or Flk-l+c-kit+ cardiovascular progenitor cells produced from the
population of human embryonic stem cells as starting cells as disclosed by
Keller et al using the method of Kattman.” (Id.) The Examiner also
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concludes that it would have been obvious “to further purify cells that are
positive and/or negative for c-kit as prior art recognized C-kit activation as
early marker for the earliest hemangioblast-derived haematopoietic and
vascular progenitors.” {Id. at 9.) The Examiner finds that “negative
expression of other marker protein such as v-cadherin are implicit
characteristics of the subpopulation of FLk-1 (KDR+) cells present in human
cardiovascular progenitor cells.” {Id.)
Appellants argue that
[t]here would not have been any reason to expect that the cell
population of Keller et al. even contained Flk-l/KDR positive,
C-kit negative cells, and thus no reason to expect that a Flk-
l/KDR positive, C-kit negative subpopulation could be isolated
from the cell population of Keller et al. . . . Further, this would
not result in a population of cells that are negative for VE-
cadherin, as presently claimed, because the cells of Keller et al.
express VE-cadherin.
(Appeal Br. 12.)
Appellants also argue that “the Examiner's statement that lack of
expression of VE-cadherin is an implicit characteristic of the cell population
of Keller et al. is also incorrect, as evidenced by the reference itself. . . .
[T]he cells of Keller et al. express the VE-cadherin gene.” (Id. at 13, citing
Keller || 54, 58, Figs. 1 and 2.) Finally, Appellants argue that “Gouon-
Evans is directed to the production of endoderm. . . . There would not have
been any reason based on Gouon-Evans to obtain human cardiovascular
progenitor cells that are negative for c-kit expression, since cardiovascular
cells are mesoderm, not endoderm, derivatives.” {Id. at 14.)
We agree with Appellants that the Examiner has not persuasively
shown that the human cardiovascular progenitor cells recited in claim 1 on
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appeal would have been obvious based on the cited references. Kattman
states that
[c] ell-tracing studies in the mouse indicate that the cardiac
lineage arises from a population that expresses the vascular
endothelial growth factor receptor 2 (VEGFR2, Flk-1),
suggesting that it may develop from a progenitor with vascular
potential. Using the embryonic stem (ES) cell differentiation
model, we have identified a cardiovascular progenitor based on
the temporal expression of the primitive streak (PS) marker
brachyury and Flk-1.
(Kattman 723, abstract.) Kattman states that “for the generation of
cardiovascular cell colonies (CV-CFC assay), EB [embryonic bodies] and
embryonic cells were plated” in a medium that included hVEGF, hbFGF,
hBMP4, and hDKK. {Id. at 730, right col. (“Colony Assays”).)
Keller discloses “cell populations that are enriched for cardiac
progenitor cells.” (Keller 111.) Keller states that “[f]or the generation of
EBs, [ES] cells were harvested and cultured in” a medium supplemented
with glutamine, transferrin, ascorbic acid, monothioglycerol (MTG), and
fetal calf serum (FCS). (Id. 142.)
Keller states that “Notch4 inhibited hematopoietic development from
this Flk-1 population. Induction of Notch4 resulted in a small increase in the
proportion of VE-cad+ endothelial cells in the aggregates.” (Id. 1 54.)
Keller also states that “expression of genes indicative of endothelial and
vascular smooth muscle development including, flk-1, ve-cad, SM22 and
pdgf]3r, were up-regulated in the Notch4-induced aggregates.” (Id. ) See
also id. 1 58 (“When cultured in the presence of Dox, these cells formed
compact colonies. . . . [M]ost of the compact colonies expressed the cardiac
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genes nkx2.5, cardiac a-actin and mlc-2a, the endothelial genes flk-1 and ve-
cad and the vascular smooth muscle gene sm22.”).
Gouon-Evans discloses that
[w]hen differentiated in the presence of activin A in serum-free
conditions, mouse embryonic stem cells efficiently generate an
endoderm progenitor population defined by the coexpression of
either Brachyury, Foxa2 and c-Kit, or c-Kit and Cxcr4.
Specification of these progenitors with bone morphogenetic
protein-4 in combination with basic fibroblast growth factor and
activin A results in the development of hepatic populations.
(Gouon-Evans 1402, abstract.)
Thus, none of the cited references expressly describes a cardiac
progenitor cells having the properties recited in claim 1 on appeal:
expression of Flk-1 /KDR, lack of expression of c-Kit and VE-cadherin, and
progenitors of cardiomyocytes, endothelial cells, and vascular smooth
muscle cells. Nor does the evidence support a conclusion that practicing the
method disclosed by any of the references would inherently result in the
claimed population of cells, because the methods described in the references
differ from that described in the instant Specification.
The Specification states that the progenitor cells recited in claim 1
were generated from embryonic bodies as follows:
From day 0-1, EBs were plated in 2 mL basic media (StemPro-
34 (lnvitrogen), 2 mM glutamine, 4 x 10'4 M monothioglycerol
(MTG), and 50 pg/mL ascorbic acid (Sigma) plus 0.5 ng/mL
BMP4 (R&D Systems). The following concentrations of factors
were used for EB formation, mesoderm induction and cardiac
specification: BMP4:10 ng/mL, hbFGF: 5 ng/mL, ActivinA: 3
ng/ml, hDKKl: 150 ng/mL, hVEGF: 10 ng/mL. The factors were
added with the following sequence: day 1-4, BMP4, hbFGF and
ActivinA; day 4-8, VEGF and DKK1; following day 8, VEGF,
DKK1, and bFGF.
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(Spec. 1 67.)
By contrast, Kattman’s method of culturing mouse embryonic stem
cells involved a medium containing hVEGF, hbFGF, hBMP4, and hDKK
but not ActivinA. In addition, Kattman does not describe including different
combinations of factors at different times during culturing, as in the
Specification. Keller’s method does not include any of the factors described
in the Specification for EB formation, mesoderm induction, and cardiac
specification. Thus, the evidence does not show that practicing the method
of either Kattman or Keller, or combining their culture conditions, would
result in cells meeting the limitations of claim 1. And, as Appellants have
pointed out, Gouon-Evans discloses a method of differentiating ES cells into
hepatocytes, not cardiovascular progenitor cells.
We therefore conclude that the Examiner has not made a prima facie
case of obviousness. The rejection of claims 1, 3—5, and 39 under 35 U.S.C.
§ 103(a) based on Kattman, Keller, and Gouon-Evans is reversed.
SUMMARY
We reverse both of the rejections on appeal.
REVERSED
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