Ex Parte Fodstad et al

Board of Patent Appeals and Interferences

Aug 22, 2011

11047913 (B.P.A.I. Aug. 22, 2011)

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.
11/047,913 02/01/2005 Oystein Fodstad FDSTD-001C 6865
7663 7590 08/22/2011
STETINA BRUNDA GARRED & BRUCKER
75 ENTERPRISE, SUITE 250
ALISO VIEJO, CA 92656
EXAMINER
YU, MISOOK
ART UNIT PAPER NUMBER
1642
MAIL DATE DELIVERY MODE
08/22/2011 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.
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________

Ex parte OYSTEIN FODSTAD and HANNE KLEPPE HOIFODT
__________

Appeal 2010-011839
Application 11/047,913
Technology Center 1600
__________

Before DEMETRA J. MILLS, FRANCISCO C. PRATS, and
JEFFREY N. FREDMAN, Administrative Patent Judges.

PRATS, Administrative Patent Judge.

DECISION ON APPEAL
This appeal under 35 U.S.C. § 134 involves claims to a method for
diagnosing disease by examining cell suspensions. The Examiner entered
rejections for obviousness.
We have jurisdiction under 35 U.S.C. § 6(b). We reverse.

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Application 11/047,913

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STATEMENT OF THE CASE
Claims 1, 2, 6-11, 13, and 15-18 stand rejected and appealed (App. Br.
5). Claim 1, the only independent claim, is representative and reads as
follows:
1. A method to diagnose a disease state in a patient,
by detecting and phenotyping live target cells in cell
suspensions to determine an antigenic finger-print of the live
target cells, the method using particles coated with antibodies
directed against antigenic determinants/receptors expressed on
the target cells, wherein the method comprises:
incubating 2 to 6 antibodies under gentle rotation
for about 5 minutes to about 2 hours with cell
suspensions containing the live target cells at 0°C to
25°C, all of the antibodies being directed against
independent antigenic determinants/receptors expressed
on the same cells, wherein each antibody is conjugated to
a visually different fluorescent or dyed non-fluorescent
particle with at least one of the particles being a
fluorescent particle and at least one of the particles being
a dyed non- fluorescent particle, said particles capable of
being instrumentally or visually separated from the other
particles by differing sizes, fluorescent emission spectra,
and/or colors, each particle ranging in size from about
0.01 μm to about 6 μm, wherein the ratio between the
number of particles and the number of cells ranges from
about 0.5 : 1 to about 20 : 1; followed by an enrichment
procedure that enriches the cell suspensions for the live
target cells; and
diagnosing the disease state by determining the
antigenic fingerprint of the live target cells via evaluation
of the live target cell rosettes microscopically by
fluorescence microscope visualizing or imaging devices,
and evaluating the antigenic fingerprint to determine the
presence or absence of the disease state.

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The following rejections are before us for review:
(1) Claims 1, 2, 6-11, and 13, under 35 U.S.C. § 103(a) as obvious
over Mirro,
1
Baran,
2
Fodstad,
3
and O‟Briant
4
(Ans. 3-13);
(2) Claims 15-17, under 35 U.S.C. § 103(a) as obvious over Mirro,
Baran, Fodstad, O‟Briant, and Hajek
5
(Ans. 13-15); and
(3) Claim 18, under 35 U.S.C. § 103(a) obvious over Mirro, Baran,
Fodstad, O‟Briant, and Wilkins
6
(Ans. 15-16).

DISCUSSION -- OBVIOUSNESS
The Examiner cites Mirro as using antibodies linked to fluorescent
microspheres for the purpose of detecting various antigens on the surfaces of
cells derived from leukemic patients (Ans. 7). The Examiner finds that
Mirro‟s process differs from the process of claim 1, and other claims, as to a
number of features:
Although Mirro et al teach using both fixed and live
cells, Mirro et al do not explicitly teach that fresh hematopoietic
cells mixed with fixed macrophages are live hematopoietic cells

1
Joseph Mirro, M.D. and Sanford A. Stass, M.D., Fluorescent Microsphere
Detection of Surface Antigens and Simultaneous Cytochemistries in
Individual Hematopoietic Cells, 83 AM. J. CLIN. PATHOL. 7-11 (1985).
2
U.S. Patent No. 4,511,662 (filed June 18, 1982).
3
WO 94/07139 A1 (published March 31, 1994).
4
K.C. O‟Briant et al., Elimination Of Clonogenic Breast Cancer Cells
From Human Bone Marrow[:] A Comparison of Immunotoxin Treatment
With Chemoimmunoseparation Using 4-Hydroperoxycyclophosphamide,
Monoclonal Antibodies, and Magnetic Microspheres, 68 CANCER 1272-78
(1991).
5
U.S. Patent No. 5,340,719 (filed November 23, 1990).
6
D.J. Wilkins, Fluorescent Labelling of Polystyrene Latex for Tracing in
Biological Systems, 202 NATURE 798-99 (1964).
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for visualization under microscope. Mirro et al do not teach
that : 1) Two to 6 antibodies are directed to independent
antigenic determininants[sic]/receptors expressed on the same
cells, 2) each antibody is conjugated to a visually different
fluorescent or dyed non-fluorescent particle with at least one of
the particles being a fluorescent particle and at least one of the
particles being a dyed non-fluorescent particle, 3) the ratio
between the number of microspheres and the number of cells
ranges from 20:1 to 0.5:1, 4) the tumor associated antigens
recited in the claims 8 and 13 of the instant application, and 5)
antibody-coated particles are incubated, under gentle rotation
for about 5 minutes to about 2 hours, with cell suspension
containing target cells at 0°C to 25°C.

(Ans. 8-9.) Despite these differences between the claims and Mirro, the
Examiner concludes that Mirro would have rendered the claims obvious
when viewed alongside the remaining cited references.
Specifically, the Examiner finds that an ordinary artisan would have
been prompted to screen and phenotype live cells according to Mirro‟s
methods “because[,] depending on the purpose of the investigation, either
fixed or live cells could be used, in view of the teaching of Fo[d]stad et al,
which teaches using either fixed or live cells” (id. at 11). For example, the
Examiner reasons, “when the identified target cancer cells need further
characterization, such as for determining specific biochemical and biological
features and growth of the target cells in suspension, live cells would be
used, in view of the teaching of Fo[d]stad” (id.). Moreover, the Examiner
contends, “live cells are commonly used in the art for screening or
separating target cells from a mixture of cells, which are characterized by
visualization of the labeled cells under microscope, in view of the teaching
of not only Fo[d]stad et al, but also of Baran” (id.).
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The Examiner further finds that, instead of using antibody-fluorescent
particle conjugates specific for a single antigen in each assay, as taught in
Mirro, an ordinary artisan would have been prompted to use “more than one
particle-conjugated antibod[y], such as 2-6 antibodies for independent
antigens on the same cells, using the method of Fo[d]stad et al, which
teaches using particle-conjugated antibodies against groups of antigens
specifically expressed on target cells” and also in view of O‟Briant, which
describes the use of “multiple microsphere-antibodies with additive binding
to target cells. (id. at 11-12). The Examiner reasons that the artisan would
have been prompted to modify Mirro‟s assays in that manner by O‟Briant‟s
teaching that “breast cancer cells vary markedly within tumors with respect
to their antibodies phenotype, and that the use of multiple monoclonal
antibodies with additive binding to target breast cancer cells, instead of
individual antibody targeting to a single antigen, can compensate for this
heterogeneity observed within and between tumors” (id. at 12).
The Examiner further concludes that an ordinary artisan would have
considered it obvious to “label different particles with different color dyes,
in addition to the fluorescent dyes taught by Mirro et al, as suggested by
Baran et al, to increase the versatility of the detection method, and for easy
distinguishing and detection of different cells bearing different markers”
(id.).
Further, the Examiner contends, an ordinary artisan would have
considered it obvious to substitute antibodies directed against tumor cells for
Mirro‟s anti-leukemic cell antibodies because Mirro‟s assay methods would
have been expected to function equally well in detecting tumor antigens, and
because O‟Briant teaches that “there is a heterogeneity of antigenic
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phenotype within tumors, such as in breast cancer cells, and that use of
multiple monoclonal antibodies can compensate for this heterogeneity
observed within and between tumors” (id.). Thus, the Examiner contends
further, “it would have been obvious to use conditions for incubating
antibody-coated microsphere or particles with target tumor cells, such as the
duration of incubation, temperature, the ratio of particles and tumor cells, as
taught by Fo[d]stad et al, because said parameters are optimal for tumor
cells” (id.).
We will not sustain this rejection.
“In rejecting claims under 35 U.S.C. § 103, the examiner bears the
initial burden of presenting a prima facie case of obviousness. Only if that
burden is met, does the burden of coming forward with evidence or
argument shift to the applicant.” In re Rijckaert, 9 F.3d 1531, 1532 (Fed.
Cir. 1993).
While the Supreme Court has emphasized “an expansive and flexible
approach” to the obviousness analysis, KSR Int’l Co. v. Teleflex Inc., 550
U.S. 398, 415 (2007), the Court has also reaffirmed the importance of
determining “whether there was an apparent reason to combine the known
elements in the fashion claimed by the patent at issue.” Id. at 418 (emphasis
added).
Thus, as our reviewing court has explained out, an examiner must
“still be careful not to allow hindsight reconstruction of references to reach
the claimed invention without any explanation as to how or why the
references would be combined to produce the claimed invention.”
Innogenetics, N.V. v. Abbott Labs., 512 F.3d 1363, 1374 n.3 (Fed. Cir. 2008)
(emphasis added).
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Accordingly, to demonstrate prima facie obviousness, “it is not
enough to simply show that the references disclose the claim limitations; in
addition, „it can be important to identify a reason that would have prompted
a person of ordinary skill in the art to combine the elements as the new
invention does.‟” Transocean Offshore Deepwater Drilling, Inc. v. Maersk
Contractors USA, Inc., 617 F.3d 1296, 1303 (Fed. Cir. 2010) (quoting
KSR, 550 U.S. at 401 (emphasis added)).
While this is arguably a close case, we are not persuaded that the
Examiner has made a prima facie case of obviousness. Claim 1 recites a
very specific process, requiring a number of specific process conditions and
parameters.
In particular, claim 1 recites a method for diagnosing a disease state in
a patient, by detecting and phenotyping live target cells in cell suspensions
to determine an antigenic finger-print of the live target cells. Claim 1
requires the practitioner to incubate 2 to 6 antibodies against different
antigens or receptors that are expressed on the same cells, under gentle
rotation for about 5 minutes to about 2 hours with cell suspensions
containing the live target cells at 0°C to 25°C.
Claim 1 requires each antibody to be conjugated to a visually different
fluorescent or dyed non-fluorescent particle with at least one of the particles
being a fluorescent particle and at least one of the particles being a dyed
non-fluorescent particle, and further requires the different particles to be
capable of instrumental or visual separation from the other particles by
differing sizes, fluorescent emission spectra, and/or colors. Claim 1 further
requires each particle to range in size from about 0.01 μm to about 6 μm,
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and further requires the ratio between the number of particles and the
number of cells ranges to be about 0.5 : 1 to about 20 : 1.
After the incubation step, claim 1 requires the practitioner to perform
an enrichment procedure that enriches the cell suspensions for the live target
cells. After enrichment, claim 1 requires the practitioner to diagnose the
disease state of the subject from whom the cells were taken by
microscopically visualizing any rosettes of antibodies bound to the live
target cells, using fluorescence microscope visualizing or imaging devices,
and from that visualization, evaluate the presence or absence of a particular
disease state.
We acknowledge, as the Examiner points out, that Mirro discloses that
antibody-fluorescent particle conjugates are useful for microscopically
determining whether cells within a particular sample population have a
particular surface antigen or antigens of interest (see Mirro 11 (“The low
background and extremely high fluorescence intensity of the microsphere
assay makes fluorescence microscopic analysis of cell surface antigen
expression easy.”)).
We also acknowledge Fodstad‟s disclosure that fluorescently labeled
antibodies can be used alongside paramagnetic particle-antibody conjugates
to microscopically visualize target cells (Fodstad 11), including tumor cells
visualized using the claimed conditions of gentle rotation (see id. at 6-7).
Thus, we agree with the Examiner that an ordinary artisan might have been
prompted by the advantages of fluorescent particle-conjugated antibodies to
use those fluorescent conjugates as the second labeled tumor cell binding
agent alongside Fodstad‟s primary paramagnetic-conjugated antibodies.
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We are not persuaded, however, that the Examiner has adequately
explained why an ordinary artisan would have been further prompted, as
claim 1 requires, to use a non-fluorescently dyed antibody-particle conjugate
in such a process, when the non-fluorescent antibody conjugate was directed
to a surface antigen present on the same cell already targeted by the other
antibody-particle conjugates. Specifically, while we agree with the
Examiner that a combination of paramagnetic particle-antibody conjugates
and fluorescent particle-antibody conjugates would have allowed an
ordinary artisan to not only enrich the target cells in the sample using the
paramagnetic conjugates (as claim 1 requires), but also microscopically
verify the presence of the target cells using the fluorescent conjugates (as
claim 1 also requires), the Examiner has not identified any apparent
advantage or reason why an ordinary artisan would have included an
additional non-fluorescently dyed conjugate capable of binding the same
target cell in the assay.
We acknowledge Baran‟s disclosure that different cell types can be
identified in samples by using fluorescently or non-fluorescently labeled
antibodies directed to the different cell types (see Baran, col. 40, ll. 44-68).
However, while Baran might explain why an ordinary artisan would have
been prompted to use distinct dyes or labels for antibody-particle conjugates
directed to different cell types, the Examiner does not explain, and it is
unclear why, this teaching would have prompted an ordinary artisan to
include an additional antibody conjugate directed to the same cell type as
claim 1 requires.
We further acknowledge O‟Briant‟s disclosure that, when combined
with sheep anti-mouse immunoglobulin conjugated to magnetic beads, a
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mixture of 5 mouse monoclonal antibodies that additively bound to breast
cancer cell lines (O‟Briant 1273-74) removed significantly more cancerous
cells from bone marrow intended for autologous transplantation in breast
cancer treatment, as compared to the number of cancerous cells eliminated
by treatment with individual antibodies conjugated to immunotoxins (see id.
at 1272 (abstract); see also id. at 1275-76). As O‟Briant explains
Breast cancer cells vary markedly within tumors and within cell
lines with regard to their antigenic phenotype. Use of multiple
monoclonal antibodies can compensate for this heterogeneity
observed within and between tumors. Additive anti-tumor
activity has been demonstrated when immunotoxins are used in
combination. In part, this has been related to the demonstration
of subpopulations of tumor cells that lack one, but not both
determinants recognized by the two immunotoxins.

(Id. at 1276 (citations omitted).)
While O‟Briant may have prompted an ordinary artisan to use a
plurality of antibodies directed to different determinants to ensure optimal
removal of cancer cells from autologous bone marrow used in breast cancer
treatment, the Examiner has not adequately explained how or why O‟Briant
would have suggested to an ordinary artisan that following Fodstad‟s
teachings would fail to identify target tumor cells, particularly when using
the two-antibody method described by Fodstad. Put another way, while
additive binding with a plurality of antibodies may have been known to be
useful when removing undesired cells from a sample, no clear explanation
has been advanced as to why additive binding would be required, or even
desirable, in assays already capable of identifying tumor cells in a sample
through the use of two antibodies.
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Thus, we are not persuaded that an ordinary artisan practicing
Fodstad‟s two-antibody assays would have viewed O‟Briant as suggesting
that the assays‟ capacity to identify a target cell would, or could, be
improved by including at least one non-fluorescent-dyed particle targeted to
an antigen, as Appellants‟ claim 1 requires, when the assay already included
paramagnetic and fluorescent particles targeted to antigens on the same cell,
as suggested by Fodstad. Accordingly, as we are not persuaded that the
Examiner has advanced sufficient fact-based reasoning explaining why
claim 1 would have been prima facie obvious to an ordinary artisan in view
of Mirro, Baran, Fodstad, and O‟Briant, we reverse the Examiner‟s
obviousness rejection of that claim and its dependents, over those references.
The Examiner also rejected claims 15-17 as obvious over Mirro,
Baran, Fodstad, O‟Briant, and Hajek (Ans. 13-15). Claims 15-17 read as
follows:
15. A method according to claim 1 wherein at least one
antibody selected from the 2 to 6 antibodies being directed
against the independent antigenic determinants/receptors
expressed on the same cells is conjugated to a magnetic or
paramagnetic particle, and wherein the enrichment procedure
enriches the cell suspensions for live target cells that are bound
to the antibody conjugated to the magnetic or paramagnetic
particle.

16. A method according to claim 15 wherein the enrichment
procedure is an immunomagnetic enrichment procedure.

17. A method according to claim 15 wherein the antibodies
being directed against the independent antigenic
determinants/receptors expressed on the same cells comprise at
least two antibodies that are conjugated to two visually different
fluorescent particles.

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The Examiner relied on Mirro, Baran, Fodstad, and O‟Briant as
discussed above, and cited Hajek as evidence that it was known in the art to
use mixtures of dyed magnetic and non-magnetic particles of distinct colors
and sizes to visually identify and characterize specific cells in samples (Ans.
13-14). Based on the references‟ combined teachings, the Examiner
concluded:
It would have been prima facia [sic] obvious to one of
ordinary skill in the art at the time the invention was made to
add to the fluorescent and non-fluorescent dyed microspheres in
the method taught by Mirro et al, and Baran et al, the magnetic
microspheres taught by Hajek et al or Fo[d]stad et al, because
magnetic microspheres provide an additional way of
differentiating or separating different target cells, in view of the
teaching of Hajek et al, or Fo[d]stad et al, such as isolation and
identification of target cancer cells with low density, as taught
by Fo[d]stad et al, or for separation of different subsets of target
cells, or separation of red blood cells from whole blood sample,
as taught by Hajek et al.

(Id. at 15.)
We reverse this rejection as well.
To the extent that Hajek discloses a combination of paramagnetically
labeled bead-antibody conjugates and a second labeled antibody for
detecting cells in a sample, Hajek is merely cumulative of Fodstad,
discussed above. To the extent the Examiner cites Hajek as suggesting using
magnetic particles in evaluating blood samples, Hajek‟s assessment of blood
cells involves cell fixation and staining (Hajek, col. 4, ll. 6-7), contrary to
the live cells evaluated in Appellants‟ claims.
We further note that Hajek suggests that its magnetic particles can be
dyed, and combined with non-magnetic particles dyed a different color (id.
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at col. 10, ll. 20-25). However, Hajek focuses on simple visual detection
methods that avoid drawbacks of fluorescence-based methods (see id. at col.
2, ll. 3-23), as well as using fixed/stained cells as opposed to live cells (see,
e.g., id. at col. 7, ll. 29-49).
We are therefore not persuaded that, when Hajek is read as a whole,
the Examiner has adequately explained why an ordinary artisan would have
combined the types of labels used by Hajek to assess fixed/stained blood
cells, with Mirro‟s fluorescent detection methods also using mostly fixed
cells, and then further combined those methods with Fodstad‟s evaluation of
live tumor cells, to arrive at the claimed process. As noted above, prima
facie obviousness is not established merely by showing the existence in the
prior art of all of the claimed elements. See Transocean, 617 F.3d at 1303;
see also KSR, 550 U.S. at 418 (“[A] patent composed of several elements is
not proved obvious merely by demonstrating that each of its elements was,
independently, known in the prior art.”).
As we are not persuaded that the Examiner has adequately explained,
with any sort of specificity, how or why an ordinary artisan would have
arrived at the processes recited in claims 15-17 from Mirro, Baran, Fodstad,
O‟Briant, and Hajek, we reverse the Examiner‟s obviousness rejection of
those claims over those references.
The Examiner also rejected claim 18 over Mirro, Baran, Fodstad,
O‟Briant, and Wilkins (Ans. 15-16). Claim 18 recites “[a] method according
to claim 1 wherein the at least one fluorescent particle comprises a
polystyrene latex fluorescent microsphere.”
The Examiner relied on Mirro, Baran, Fodstad, and O‟Briant for the
teachings discussed above, and cited Wilkins as evidence that polystyrene
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latex particles were known in the art to be useful “for tracing in biological
systems” (Ans. 16). As the Examiner points to no teaching in Wilkins that
remedies the shortcomings discussed above of Mirro, Baran, Fodstad, and
O‟Briant as they relate to the method of claim 1, we reverse this rejection as
well.

SUMMARY
We reverse the Examiner‟s obviousness rejection of claims 1, 2, 6-11,
and 13 over Mirro, Baran, Fodstad, and O‟Briant.
We also reverse the Examiner‟s obviousness rejection of claims 15-
17, under 35 U.S.C. § 103(a) as obvious over Mirro, Baran, Fodstad,
O‟Briant, and Hajek.
We also reverse the Examiner‟s obviousness rejection of claim 18
over Mirro, Baran, Fodstad, O‟Briant, and Wilkins.

REVERSED

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