Ex Parte Luitjens et al

Patent Trial and Appeal Board

Sep 25, 2017

13578763 (P.T.A.B. Sep. 25, 2017)

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.
13/578,763 08/13/2012 Alfred Luitjens 2578-9913.1US 8188
24247 7590 09/27/2017
TRASKBRITT, P.C.
P.O. BOX 2550
SALT LAKE CITY, UT 84110
EXAMINER
POPA, ILEANA
ART UNIT PAPER NUMBER
1633
NOTIFICATION DATE DELIVERY MODE
09/27/2017 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):
U S PTOMail @ traskbritt .com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte ALFRED LUITJENS and HERMAN VAN HERK1
Appeal 2015-007716
Application 13/578,763
Technology Center 1600
Before DONALD E. ADAMS, JOHN G. NEW, and TAWEN CHANG,
Administrative Patent Judges.
CHANG, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal under 35 U.S.C. § 134(a) involving claims to a
method for producing certain virus particles, which have been rejected as
obvious and on the ground of non-statutory obviousness-type double
patenting. We have jurisdiction under 35 U.S.C. § 6(b).
We AFFIRM.
1 Appellants identify the real party in interest as CRUCELL HOLLAND
B.V. (Appeal Br. 2.)
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STATEMENT OF THE CASE
Adenoviruses have been identified in several avian and mammalian
hosts and are “attractive targets for the delivery and expression of
heterologous genes,” including for use in DNA vaccination. (Bett2 1:10-11,
21; Spec. 13.) Human adenovirus serotypes (i.e., serologically
distinguishable strains of the virus such as Ad5, Ad26, and Ad35), have been
categorized into subgenera A—F based on certain biological, chemical,
immunological and structural criteria. (Bett 1:17—20.)
The Specification states that producing adenovirus on adherent cell
cultures “cannot fulfill the worldwide demand for adeno-based vaccines,”
but using suspension cultures to scale up the production processes may
require large-scale bioreactors and high capital investment. (Spec. Tflf 4—5.)
The Specification further states that “[o]ne of the issues encountered in
adenovirus production optimization is the so-called ‘cell density effect,’”
wherein virus productivity per cell may decrease as cell density increases.
{Id. 17.) According to the Specification, therefore, “a need exists to
improve systems for adenovirus production, to improve yields of adenovirus
particles in order to fulfill the worldwide demand of adenovirus vaccines,
preferably at non-prohibitive costs.” {Id. 1 6.)
Claims 13—20, 22, 24—26, 28, 31—39, and 41—493 are on appeal.
Claims 24 and 49 are illustrative and produced below:
2 Bett et al., WO 2006/086284 A2, published Aug. 17, 2006.
3 As Appellants point out and the Examiner acknowledged, claim 49 was not
discussed in the Final Rejection. (Final Act. 3—4, 5; Appeal Br. 8; Ans. 3.)
Because Appellants and the Examiner both address this claim for purposes
of the appeal (Appeal Br. 8; Ans. 3), we treat claim 49 as rejected and
address it in our opinion.
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24. A bioreactor comprising a perfusion system, culture
medium, PER.C6® cells in a suspension thereof, and at least 1 x
1012 recombinant adenovirus serotype 26 (rAd26) virus particles
(VP)/mL, wherein the bioreactor has a working volume of
between 2 L and 1000 L, and wherein the rAd26 virus particles
have an infectious particle (VP/IU) ratio less than 30:1.
49. A method for producing recombinant adenovirus
serotype 26 (rAd26) virus particles (VP), the method
comprising:
culturing PER.C6® cells in suspension m a first
bioreactor having an alternating tangential flow (ATF)
perfusion system;
transferring PER.C6® cells from the first bioreactor to a
second bioreactor having an ATF perfusion system;
infecting the PER.C6® cells in the second bioreactor at a
density of between 10 x 106 and 16 x 106 viable cells/mL with
rAd26;
further culturing the infected PER.C6® cells in the second
bioreactor, thereby producing rAd26 virus particles with a unit
productivity of between about 0.5 x 105 and 1.5 x 105
VP/infected PER.C6® cell, for between about 2 and about 5
days;
to produce in the second bioreactor a culture comprising
at least 1 x 1012 rAd26 VP/mE having a virus particle to
infectious particle (VP/IU) ratio less than 20:1; and
harvesting rAd26 virus particles from the culture.
(Appeal Br. 26, 30 (Claims App.).)
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The Examiner rejects claims 13—20, 22, 24—26, 28, 31—39, and 41—49
under 35 U.S.C. § 103(s) as being unpatentable over Bett, Havenga,4
Crowley,5 and Dai.6 (Ans. 2.)
The Examiner rejects claims 13—20, 22, 24—26, 28, 31—39, and 41—49
on the ground of non-statutory obviousness-type double patenting as being
unpatentable over claims 1—3, 5, 6, 8—10, 12—14, 16, 18—20, 23—29, 32, and
35 of copending Application No. 13/126,978. (Ans. 7.)
I.
Issue
The Examiner finds claims 13—20, 22, 24—26, 28, 31—39, and 41—49 to
be obvious over Bett, Havenga, Crowley, and Dai. The Examiner finds that
Bett teaches “a method of producing a recombinant Ad26 in PER.C6 cells
for gene therapy, the method comprising infecting the cells with a
recombinant Ad26 . .., culturing the cells, and harvesting the produced
recombinant virus.” (Ans. 3.)
With respect to the limitation relating to the VP:IU ratio, the
Examiner finds that Havenga teaches that “PER.C6 cells facilitate enhanced
viral replication and improved quality for recombinant adenoviruses
provided that the recombinant adenoviruses comprise a deleted El [gene]
and a deleted E4-Orf6 [coding sequence] replaced by the Ad5 E4-Orf6
4 M. Havenga et al., Novel replication-incompetent adenoviral B-group
vectors: high vector stability and yield in PER.C6 cells, 87 J. General
Virology 2135 (2006).
5 Crowley et al., WO 2005/095578 Al, published Oct. 13, 2005.
6 WT Dai et al., Abstract, Comparative study of the replication difference of
HearNPV in infected exponential and stationary host cells, 23 Bing Du Xue
Bao 399 (2007).
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[coding sequence],” and further teaches “achieving VP/IU ratios of about 9.7
and specific productivities of about 105 VP/cell.” (Id. ) The Examiner finds
that, while Havenga used Ad35 rather than the claimed Ad26, Havenga
teaches that replacing native E4-Orf6 in an adenovirus with Ad5 E4-Orf6 to
achieve high specific productivity and high quality virus in PER.C6® cells is
likely to be a “universal method,” including for subgroup D adenoviruses
such as Ad26. (Id. at 3 4.)
The Examiner finds that Bett does not teach a perfusion system for
culturing cells. (Id. at 4.) However, the Examiner finds that Crowley
teaches “growing PER.C6 cells in a 4L bioreactor connected to an ATF
perfusion system, wherein using the ATF system results in extremely high
densities of highly viable cells (about 80xl06/ml. . .) and ... is suitable for
the production of large amounts of molecules of interest such as viral vectors
for gene therapy.” (Id.) The Examiner also finds that Bett, Havenga, and
Crowley do not “specifically teach infecting the cells at a density of about
10-14xl06.” (Id. at 5.) However, the Examiner finds that Dai teaches that
“infecting producer cells in their exponential phase results in higher
infection and also in higher and faster production of viral particles.” (Id.)
With respect to the limitation of producing virus particles at a concentration
of at least lxl012 VP/mE, the Examiner finds that this limitation is suggested
by the combination of Bett with Havenga, which teaches productivity of
about 105 VP/cell, and Crowley, which teaches achieving cell densities of
80x106 cells/ml. (Id.)
The Examiner concludes that, in light of Crowley’s teaching of ATF
perfusion system resulting in “extremely high densities of highly viable
cells,” a skilled artisan would have reason to use Crowley’s ATF perfusion
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system in Bett’s method of producing vims particles with a reasonable
expectation of success, “in order to obtain high densities of viable PER.C6
cells available for infection and thus enhanced yields of therapeutic
recombinant Ad26 vectors.” (Id. at 4—5.) The Examiner further concludes
that Dai teaches that cell density at the time of infection is a result-effective
variable; thus, it would be obvious to optimize such cell density to arrive at
the claim limitation relating to infecting the PER.C6® cells when the cells
have reached a particular range of density. (Id. at 5—6.)
Finally, with regard to those limitations in certain claims relating to
transferring cells from a first bioreactor to a second bioreactor and culturing
time, the Examiner finds that a skilled artisan would have found it obvious
“to harvest the cells from a first bioreactor and seed them into several
bioreactors or a bigger bioreactor for infection to achieve the predictable
result of scaling-up the process” and “to optimize the yield by varying the
culturing time.” (Id. at 6.)
Appellants contend that the cited art combination does not teach or
suggest a method of producing rAd26 vims particles in PER.C6® cells that
results in cell cultures having the claimed viral yield, unit productivity, and
infectious particle (VP/IU) ratio after the claimed culturing period, and that a
skilled artisan would have no reasonable expectation that such a culture
could be achieved. (Appeal Br. 8—11, 13—15, 17—20.) Appellants also
contend that, contrary to the Examiner’s finding, “[vjirus producer cell
density was not known to be a result-effective variable for either the purpose
of increasing viral titer or VP/IU ratio in adenovims at the time of the
application.” (Id. at 11—12.) Appellants further contend that the subject
matter of the claims exhibit unexpected results. (Id. at 13—15.)
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With respect to claims 39, 48, and 49, Appellants additionally contend
that the claims are non-obvious because they “employ[] a non-obvious
arrangement of steps involving multiple bioreactors.” {Id. at 15.) With
respect to claim 24, Appellants further contend that the Examiner improperly
conflated the analysis of that product claim with the analysis of method
claims such as claims 13, 48, and 49. {Id. at 20-21.)
The issues with respect to this rejection is (1) whether the evidence of
record supports the Examiner’s conclusion that the cited references render
obvious the claimed methods and bioreactor, and, if so, (2) whether
Appellants have provided evidence of unexpected results that, when
considered together with evidence of obviousness, shows the claims to be
non-obvious.
Findings of Fact
1. Bett teaches that adenoviruses are “attractive targets for the
delivery and expression of heterologous genes” because they “are able to
infect a wide variety of cells ...[,] are very efficient in introducing their
DNA into infected host cells,” “have not been found to be associated with
severe human pathology in immuno-competent individuals,” “can be
produced at high virus titers in large quantities,” and have “very well
characterized” genome and “some general conservation . . . amongst the
various serotypes.” (Bett 1:21—28.)
2. Bett teaches that there is a need to develop adenoviral vectors
based on serotypes that are less prevalent than adenovirus serotypes 2 and 5,
because pre-existing immunity may limit the efficient delivery to, and
expression of heterologous genes at, the target site when vectors based on
more prevalent serotypes are used. {Id. at 2:3—17, 3:2-4, 11—14, 5:19-22.)
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3. Bett teaches “a recombinant, replication-defective adenovirus
of serotype 26,” a subgroup D adenovirus, and “methods for producing [such
adenovirus] comprising ... (1) introducing [the adenovirus] into appropriate
adenoviral El-complementing cells and (2) allowing for the production of
viral particles.” (Bett, Abstract, 2:18, 5:27—30, 8:22—25.)
4. Bett teaches that
[s]afety in utilizing adenoviruses as gene delivery vehicles can
be enhanced by rendering the viruses replication-defective
through deletion/modification of the essential early-region 1
(“El”) of the viral genomes, rendering the viruses . . .
essentially devoid ... of El activity and, thus, incapable of
replication in the intended host/vaccine [] .... Deletion of
adenoviral genes other than El (e.g., in E2, E3, and/or E4),
furthermore, creates adenoviral vectors with greater capacity for
heterologous gene inclusion.
(Id. at 1:29-34.)
5. Bett teaches that
[a]denovirus serotype 26 vectors in accordance with [its]
invention are at least partially deleted/mutated in El such that
any resultant viruses are devoid (or essentially devoid) of El
activity, rendering the vectors incapable of replication in the
intended host. Preferably, the El region is completely deleted
or inactivated. The adenoviruses may contain additional
deletions in E3, and other early regions, albeit in situations
where E2 and/or E4 is deleted, E2 and/or E4 complementing
cell lines may be required to generate recombinant, replication-
defective adenoviral vectors.
(Id. at 7:15-20.)
6. Bett teaches an example of constructing
pAd26AEl AE4Ad50rf6, which is an “Ad26 pre-Ad plasmid containing an
El deletion and an E4 deletion substituted with Ad5 Orf6 in order to enable
efficient propagation in existing group C/Ad5 El complementing cell lines”
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as well as pAd26AElAE4Ad50rf6 plasmids further containing a HIV-1 gag
or a SEAP expression cassette, designated pAd26AElgagAE4Ad50rf6 and
pAd26AElSEAPAE4Ad50rf6, respectively. {Id. at 22:22—23:14; see also
id. at 24:30—25:12 (example of an Ad26 pre-Ad plasmid containing El and
E3 deletions and an E4 deletion substituted with Ad5 Orf6 (pAd26AEl
AE3 AE4 Ad5 Orf6).)
7. Bett teaches using PER.C6® cell line, an El-complenting cell
line, for the propagation and rescue of recombinant adenoviruses of its
invention. {Id. at 7:26—8:7, 8:13—18.)
8. Bett teaches an example of rescuing pre-adenovirus plasmids
pAd26AElAE4Ad50rf6, pAd26AElgagAE4Ad50rf6, and
pAd26AElSEAPAE4Ad50rf6 into virus by transfecting Pme I-digested
plasmids into PER.C6® cells, which “releases the viral genome from plasmid
sequences allowing viral replication to occur after cell entry,” and using the
lysates of these cells to further infect additional PER.C6® cells. {Id. at
24:6-27.)
9. Havenga teaches that “replacement of the E4-Orf6 region of
Ad35 by the E4-Orf6 region of Ad5 resulted in successful propagation of an
El-deleted rAd35 vector on existing El-complementing cell lines, such as
PER.C6 cells” and that “[t]he ability to produce these carriers on PER.C6
contributes significantly to the scale of manufacturing of rAd35-based
vaccines.” (Havenga, Abstract.)
10. Havenga teaches that reasons to seek production of El-deleted
rAd35 vector on PER.C6® cells rather than using PER.C6®/55K, a novel,
specifically engineered cell line that complements for the El deficiency in
rAd35 and expresses Ad35-derived E1B-55k protein, include “the excellent
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documentation and safety data on the PER.C6 cell line, the scalability of the
cells without the need for either micro-carrier support or serum
components^] and the know-how on growing PER.C6 cells in batch, fed-
batch and continuous-perfusion systems.” {Id. at 2142, left column.)
11. Havenga teaches obtaining VP : p.f.u. ratio of 9.7 ± 1.8 when
using rAd35-50rf6 vector on PER.C6® cells. {Id. at 2139, left column.)
12. Havenga teaches a yield of 105 VP rAd35 per cell with
PER.C6® cells growing at 10 million cells ml'1 at the 10 1 scale. {Id. at 2139,
right column.)
13. Havenga teaches that
[t]he method of swapping native adenovirus Orf6 sequences for
Ad5 E4-Orf6 in the backbone B2-group vectors, facilitating
enhanced replication and improving quality (improved VP :
p.f.u. ratio) on Ad5 El-expressing complementing cell lines, is
likely to be a universal method, as replication-deficient
subgroup D viruses carrying Ad5 E4-Orf6 sequence also
demonstrate enhanced replication on PER.C6 cells (data not
shown).
{Id. at 2142, left column.)
14. Crowley teaches
a process for the culturing of cells by continuous perfusion
culturing of a cell culture comprising cell culture medium and
cells, wherein cell culture medium is added to the cell culture,
the cell culture is circulated over a filter module comprising
hollow fibers resulting in an outflow of liquid having a lower
cell density than the cell culture and the flow within the filter
module is an alternating tangential flow.
(Crowley, Abstract.)
15. Crowley teaches that,
by perfusion culturing of animal, in particular mammalian, cells
or yeast cells according to [its] invention, extremely high viable
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cell densities can be obtained, whereas the cell culture further
displays an extremely high cell viability. Furthermore, it was
found that the perfusion process of the invention leads to less
cell aggregation in the culture, and even to a culture being a
suspension of single cells without visible aggregates.
(Id. at 1:12-17.)
16. Crowley teaches that,
[according to the process of [its] invention, an extremely high
viable cell density is a density of at least 80 x 106 cells per mL,
preferably at least 100 x 106 cells per mL, more preferably at
least 110 x 106 cells per mL, more preferably at least 120 x 106
cells per mL, more preferably at least 130 x 106 cells per mL,
most preferably at least 140 x 106 cells per mL. Typically, a
suitable upper limit in the cell density may lie around 500 x 106
cells per mL.
Surprisingly, the extremely high cell density of the
process of the invention is accompanied by an extrem[e]ly high
cell viability. An extremely high cell viability is a viability of
at least 90%, preferably at least 95%, more preferably at least
97%, most preferably at least 99%.
(Id. at 3:19-28.)
17. Crowley teaches that “[c]ells that are advantageously subjected
to the process of [its] invention may be any cell type benefiting from this
process, i.e. [,] culturing to an extremely high viable cell density and an
extremely high cell viability.” (Id. at 3:16—18.) Crowley further teaches
that, “[m]ost preferably, PER.C6® cells are used.” (Id. at 4:21—23.)
18. Crowley teaches that, in one embodiment of its invention,
a biological substance is produced by the cells. The biological
substances that can suitably be produced in the perfusion
culturing of the cell are in principle all biological substances
that can be produced by animal, especially mammalian, and
yeast cells, for example therapeutic and diagnostic proteins,
such as monoclonal antibodies, growth factors or peptide
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hormones, enzymes, polynucleotides, such as viral vectors used
in gene therapy, vaccines, etc.
{Id. at 6:4—9; see also id. at 6:34—7:5 (biological substance in the outflow
may be further processed downstream, including, e.g., through steps to
remove viruses).)
19. Crowley teaches an example relating to process optimization of
PER.C6® for biopharmaceutical production, which included production of
human IgG using PER.C6® cells cultured in medium in a 4L reactor using an
alternating tangential flow (ATF) perfusion system, which achieved a
maximum viable cell density of 100 x 106 cells/mL. {Id. at 7:10—10:9; see
also id. at 10:11—13:25 (Example 2 showing effect of various perfusion
culturing conditions on viable cell count, viability, and IgG production in
PER.C6® cells cultured using an ATF perfusion process).)
20. Crowley shows that continuous perfusion using an ATF
retention device resulted in higher maximum viable cell density,
productivity, and yield improvement factor greater than continuous
perfusion using a spin filtering retention device or an acoustic retention
device. {Id. at 10:1—5 (Table 1).)
21. Dai teaches that
the amounts of BV [(budded virions) of HearNPV] entering and
releasing, the final progeny virions and viral protein products in
the infected exponential phase [HzAMl] cells were . . . higher
than that in the stationary phase cells. 25% of the total
synthesized viral DNAs were released from infected
exponential phase cells, but [only] 13% from the infected
stationary phase cells. . . . [I]n infected exponential phase cells,
BVs were started to release from 18-20 h p.i. [(hours post­
infection)], and BVs were started to release from 22-25 h p.i.
from infected [stationary] phase cells. During 30-60 h p.i., the
BY releasing rate was about 483 copies/cell/h in the
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exponential phase cells, but was 100 copies/cell/h in the
stationary-phase cells. The initial viral DNA entering into
exponential phase cells was much more than that entered into
the stationary phase cells. The data of cell membrane fluidity at
exponential and stationary phases suggested that the fluidity of
cell membrane played an important role during virus entry.
(Dai, Abstract.)
22. Henry7 teaches that “[o]ne of the major limitations in the
production of adenoviral vectors is the reduction in cell-specific productivity
observed for increasing cell density at infection in batch cultures.” (Henry,
Abstract.) Henry teaches that “these limitations have been partially
overcome through other feeding strategies, such as fed-batch and sequential
batch operations.” (Id.)
23. Henry teaches using an acoustic filter-based perfusion culturing
system “to increase the volumetric productivity of HEK-293 cell cultures, by
allowing productive infection at higher cell densities.” (Id.; see also id. at
768, left column.)
24. Henry teaches that both cell viability and cell density at
infection are result effective variables for virus production in perfusion
cultures. (Id. at 768, left column (stating that “[c]ell viability is a
determining factor for the yield of production”), 769, left column (discussing
effects of cell density at infection for perfusion cultures).)
7 Olivier Henry et al., Insights Into Adenoviral Vector Production Kinetics in
Acoustic Filter-Based Perfusion Cultures, 86 Biotechnology and
Bioengineering 766 (2004).
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25. Xie8 studies “PER.C6® cells growth, metabolism, and
adenovirus production . . . under different pH conditions.” (Xie, Abstract.)
26. Xie teaches an experiment in which “four bioreactors were
infected with an adenovirus vector under four different pH conditions,”
wherein “[t]he four bioreactors were inoculated with a common cell source
that was cultivated in a 2-L bioreactor at pH 7.3.” (Id. at 571, left column.)
27. Chartrain9 “provides an overview of the upstream technologies
used in the industrial production of therapeutic monoclonal antibodies
(mAbs) based on the cultivation of mammalian cells.” (Chartrain, Abstract.)
28. Chartrain describes “the seed or expansion train” in the
cultivation of mammalian cells for industrial purposes and explains that “the
seed train has a simple goal — generation of enough cell mass to inoculate
the final production reactor.” (Id. at 457, right column.)
29. Chartrain describes a “common approach[] for seed train
processes” as follows:
It is usual to consider a 10 fold dilution factor as maximum and
safe for these transfers, and this will minimize the number of
vessel transfers. . . .
A “rolling seed train” is generated from cells contained in
. . . vial[(s)]. . . that are thawed and sequentially expanded to
yield a desired volume that is used to inoculate a bioreactor. . . .
Every few days, a substantial volume is drained from the
reactor and used to seed the production bioreactor. An equal
8 Liangzhi Xie, Serum-Free Suspension Cultivation of PER. C6® Cells and
Recombinant Adenovirus Production Under Different pH Conditions, 80
Biotechnology and Bioengineering 569 (2002).
9 Michel Chartrain et al., Development and Production of Commercial
Therapeutic Monoclonal Antibodies in Mammalian Cell Expression
Systems: An Overview of the Current Upstream Technologies, 9 Current
Pharm. Biotechnology 447 (2008).
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volume of fresh medium is added to the seed reactor, thus
allowing the remaining cells to multiply again. . . .
The number of expansion steps is a function of cell bank
vial size, volume of available bioreactors, cell growth rates, and
desired split ratios.
(Id. at 457-458.)
30. Heidemann10 teaches that “[i]n commercial manufacturing of
recombinant proteins from mammalian cells the seed-train expansion of
cryo-preserved cells is a vital step necessary to initiate a new production
campaign” and that “[t]his scale-up process is critical since the quality of the
inoculum often determines the success of the entire production campaign.”
(Heidemann 99, left column.)
31. Heidemann teaches “[a] new approach ... to minimize the time
and more carefully monitor and control the seed-train expansion process of
recombinant mammalian cell lines,” wherein “50 or 100 ml cryo-bags that
contain frozen cells at high cell densities” are “thawed and transferred
directly into [an inoculation] bioreactor that has been modified such that pH,
DO [(dissolved oxygen)] and temperature can be controlled at the initial
volume of two liters (the working volume eventually increase[ing] to 12 1).”
(Id. at Abstract.)
32. Heidemann teaches using bioreactors having a perfusion system
as inoculation bioreactors. (Id. at 102 (right column), 103 (bridging
paragraph).)
33. Heidemann teaches that by using its process “[t]he interval
between cell thawing and the accumulation of sufficient cell mass to
10 Rudiger Heidemann et al., A New Seed-Train Expansion Method for
Recombinant Mammalian Cell Lines, 38 Cytotechnology 99 (2002).
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inoculate a production reactor is reduced by at least 25 to 30 days compared
to the conventional method that begins with the thaw of 1—2 ml cryo-vials.”
(Id. at Abstract.)
Analysis
We adopt the Examiner's findings of fact and reasoning regarding the
scope and content of the prior art (Final Act. 5—10; Ans. 2—6, 7—32; FF1—
FF33) and agree with the Examiner that claims 13, 24, 39, 48, and 49 are
obvious over Blanc ’113. We address Appellants’ arguments below.
Claim 49
Appellants contend that the production properties of different
adenovirus serotypes are not generalizable. (Appeal Br. 9; see also Reply
Br. 3.) Appellants, thus, argue that a skilled artisan would not have
reasonably expected to obtain useful titers of Ad26 using the method of
claim 49 even if “a different adenoviral serotype (i.e., Ad35) is capable of
being produced in PER.C6® cells with the specific productivity and
infectivity claimed for Ad26.” (Appeal Br. 9; see also id. at 10-11, 13.)
Appellants cite as support two declarations of an inventor, Alfred Fuitjens,
as well as the Specification, which states that Ad26 differs from Ad5 in
showing a less pronounced cell density effect and differs from Ad35 in that
“cells . . . infected with Ad26 tend to grow further after infection[] while
cells infected with Ad35 show a decreased growth post infection.” (Id. at 9—
10; Spec. H12, 14.) Appellants further argue that Havenga is directed to
solving problems specific to rAd35 production and teaches that “adenoviral
production characteristics of Ad35 cannot be extrapolated to other
adenoviruses.” (Appeal Br. 10-11; Reply Br. 5—8.)
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We are not persuaded. Even though some growth characteristics may
differ among different adenovirus serotypes, Havenga specifically teaches
that its particular method of swapping native adenovirus Orf6 for Ad5 E4-
Orf6 to enhance viral replication and quality in cells lines such as PER.C6®
“is likely to be a universal method, as replication-deficient subgroup D
viruses carrying Ad5 E4-Orf6 sequence[s] also demonstrate[d] enhanced
replication on PER.C6 cells.” (FF13.) Ad26 is a subgroup D adenovirus,
and Bett also teaches examples of replication-deficient rAd26 that carry Ad5
E4-Orf6 sequence “to enable efficient propagation in existing Group C/Ad5
El complementing cell lines” such as PER.C6®.11 (FF3; FF6.) Neither of
the Luitjens Declarations persuasively explain why the above disclosures do
not render the claimed invention obvious to a skilled artisan: The April 29,
2013 Luitjens Declaration12 does not mention Bett and Havenga at all, while
the December 10, 2013 Luitjens Declaration13 fails to specifically address
the disclosures contained in those references and relied on by the Examiner.
Appellants contend that, “[ejven if Havenga . . . were correct that
whatever unreported results they obtained in undisclosed group D
adenoviruses were generalizable, that in no way implies that the effect
11 Appellants contend that “[i]t is . . . worth noting . . . that Bett does not
teach any importance for the Ad5 E4-Orf6 sequence.” (Reply Br. 10.) As
an initial matter, Bett does not need to teach the importance of the Ad5 E4-
Orf6 sequence, since Havenga does so. “Non-obviousness cannot be
established by attacking references individually where the rejection is based
upon the teachings of a combination of references.” In re Merck & Co., 800
F.2d 1091, 1097 (Fed. Cir. 1986). Moreover, as shown here, Bett teaches
that the purpose of using rAd26 carrying the Ad5 E4-Orf6 sequence is to
“enable efficient propagation” in cell lines such as PER.C6®.
12 Declaration of Alfred Luitjens under 37 C.F.R. § 1.132 (Apr. 29, 2013).
13 Declaration of Alfred Luitjens under 37 C.F.R. § 1.132 (Dec. 10, 2013).
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would be dramatic or significant in any particular D adenovirus.” (Reply Br.
7.) However, “expectation of success need only be reasonable, not
absolute.” Pfizer, Inc. v. Apotex, Inc., 480 F.3d 1348, 1364 (Fed. Cir. 2007).
Given the enhanced viral replication and quality achieved by rAd35 in
Havenga and the explicit teaching that its method is also applicable to
subgroup D viruses, we find that a skilled artisan would have a reasonable
expectation of success of arriving at the claimed invention by combining the
cited prior art.
Appellants next argue that a skilled artisan would not reasonably
expect to extrapolate the cell growth in Crowley’s ATF perfusion system to
cells used in adenovirus production, because “[vjiras infected cells ... are
not as robust in culture as uninfected cells.” (Appeal Br. 10.)
We remain unpersuaded. Crowley teaches a process of ATF
perfusion culturing where extremely high viable cell densities can be
obtained with extremely high cell viability. (FF15.) Crowley teaches that
according to its invention “an extremely high viable cell density is a density
of at least 80 x 106 cells per mL.” (FF16.) While Appellants are correct that
the particular examples disclosed in Crowley relate to IgG-expressing
PER.C6® cells (Appeal Br. 10; FF19), Crowley also teaches that biological
substances that can be suitably produced via its culturing process include
viral vectors used for gene therapy or vaccines (FF18).
A prior art reference is relevant for all that it teaches to those of
ordinary skill in the art, not just what is contained in the examples. Cf.
Beckman Instruments, Inc. v. LKB Produkter AB, 892 F.2d 1547, 1551 (Fed.
Cir. 1989) (“Even if a reference discloses an inoperative device, it is prior art
for all that it teaches.”). Appellants cite to the Specification to show that
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virus-infected cells are more fragile (Appeal Br. 10); however, Appellants
have not pointed to persuasive evidence that contradicts Crowley’s
suggestion that its ATF perfusion culturing process is nevertheless suitable
for producing high viable cell densities of virus-producing cells. We,
therefore, agree with the Examiner that a skilled artisan would have a
reasonable expectation of success in culturing rAd26-infected PER.C6® cells
at the high viable cell densities taught by Crowley using an ATF perfusion
culturing process.
Appellants further argue that, contrary to the Examiner’s finding,
“[vjirus producer cell density was not known to be a result-effective variable
for either the purpose of increasing viral titer or VP/IU ratio in adenovirus at
the time of the application.” (Appeal Br. 11; see also Reply Br. at 10-11.)
Appellants concede that the Dai reference cited by the Examiner shows that
“the yield of some viruses . . . may be increased by increasing the density of
some producer cells ... at infection,” but argue that this is not the case for
all viruses. (Appeal Br. 11; FF11.) Appellants cite to Henry to show that
increasing cell density may not lead to higher viral titers or higher quality
virus because of a “cell density effect,” and argue that the Examiner’s
conclusion otherwise is based on impermissible hindsight. (Appeal Br. 11—
12.)
As Appellants point out, Henry teaches that “[o]ne of the major
limitations in the production of adenoviral vectors is the reduction in cell-
specific productivity observed for increasing cell density at infection in
batch cultures.” (FF22.) Thus, Henry in fact supports the Examiner’s
finding that cell density at time of infection is a result effective variable with
respect to virus production by the cell culture (i.e., cell density at time of
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infection affects vims production). (FF24.) Instead, Appellants’ argument
appears to be that a skilled artisan would not find it obvious to “optimize”
cell density at infection to the density claimed (i.e., between 10 x 106 and 16
x 106 viable cells/mL) because of Henry’s teaching regarding the cell density
effect, or that the prior art teaches away from the claimed invention.
We are not persuaded. Dai and Henry, as well as other references
cited by the Examiner,14 show that viable cell density at the time of infection
is a result effective variable in the production of a vims, including
adenovims. Appellants argue that Henry shows that increasing the cell
density above 3 x 106 cells/mL (i.e., fewer than the claimed cell density at
infection) “resulted in a net decrease of viral yields obtained” even in a
perfusion system. (Appeal Br. 12.) However, Henry studied HEK-293 cell
culture in a perfusion system with an acoustic cell separator, rather than
PER-C6 cell culture in an ATF perfusion system. (FF23.) Crowley teaches
that culturing PER.C6® cells in a perfusion system with ATF retention
device resulted in higher maximum viable cell density as well as higher
14 See, e.g., Nedim E. Altaras et al., Production and Formulation of
Adenovirus Vectors, 99 Advances in Biochemical Eng’g/Biotechnology
193, 217—18 (2005) (stating that “[t]he cell density at infection is a very
important parameter as it impacts on the volumetric adenovims
productivity”); Inn H.Y. Yuk et al., Perfusion Cultures of Human Tumor
Cells: A Scalable Production Platform for Oncolytic Adenoviral Vectors, 86
Biotechnology and Bioengineering 637, 640 (2004) (explaining
disparity in vims titers as a consequence of differences in viable cell density
(VCD) at the time of infection). We note that, while Appellants allege the
Examiner relied on previously uncited references such as Altaras in the
Answer (Reply Br. 2), Appellants explicitly state in the Reply Brief that they
will respond rather than petition to designate a new ground of rejection.
(Id.) Accordingly, we address all of the arguments presented in the Answer
and the Reply Brief.
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productivity when compared to culturing such cells in a perfusion system
with an acoustic retention device. (FF20.) Accordingly, we agree with the
Examiner that a skilled artisan would have a reasonable expectation of
success in optimizing the cell density at infection to within the claimed cell
density ranges.
Appellants argue that ‘Tf|he cited references do not describe or make
obvious the transfer of infected producer cells to a second bioreactor
midway through the adenovirus production process.” (Appeal Br. 15—17.)
Citing Xie, Heidemann, and Chartrain, the Examiner argues that such a
transferring step is conventional in the prior art. (Ans. 28.) The Examiner
finds that such a transferring step “achieve[s] the predictable result of
scaling-up the process” and further finds that Heidemann and Chartrain
provides a reason to introduce such as step in the methods of Bett and
Crowley because they teach that “the transferring step minimizes the time
necessary to accumulate enough cell mass for production, i.e., minimizes
production time.” {Id. at 6, 28—29 (emphasis omitted).)
We find the Examiner to have the better argument.15 We note as an
initial matter that claim 49 does not require transfer of infected producer
cells as suggested by Appellants. In fact, the claim recites infecting the
PER.C6® cells in the second bioreactor. (Appeal Br. 30 (Claims App.).)
Xie, Heidemann, and Chartrain each disclose using cells growing in a first
15 Appellants argue in the Appeal Brief that the Board should ignore Xie,
Heidemann, and/or Chartrain because they were not cited in the Examiner’s
rejection. As previously noted, however, Appellants explicitly state in the
Reply Brief that they will respond to the Examiner’s Answer rather than
petition to designate a new ground of rejection. See supra n.8. Accordingly,
we address the parties’ arguments with respect to these references.
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bioreactor to “seed” additional reactors, i.e., to transfer cultured cells from a
first (e.g., inoculating) bioreactor to a second (e.g., production) reactor.
(FF25-FF33.)
Appellants argue that the references cited by the Examiner are “not in
the field of adenovirus production, and in addition do not appear to mention
transfer between two different perfusion bioreactors in the indicated
passages.” (Appeal Br. 16 n.4.) Appellants further argue that the
Examiner’s proffered rationale of transferring the cells to scale up the
culturing process is not persuasive because transfer dilute the concentration
of cells and also involve risks such as contamination. {Id. at 16.)
We are not persuaded. Xie discusses adenoviral production (FF26),
and, more importantly, Appellants have provided no reason why the scaling
up process in industrial production of adenoviruses from cultured cells
would differ from industrial production of monoclonal antibodies or
recombinant proteins from those cells. Likewise, Appellants do not explain
why—given Crowley’s disclosure of the benefits of an ATF perfusion
system—a skilled artisan would not find it obvious to transfer cells between
inoculating and production bioreactors having ATF perfusion systems
during the scaling up process. We also note that Heidemann teaches using
bioreactors having a perfusion system as inoculation bioreactors. (FF32.)
Ultimately, Appellants have provided only attorney arguments and no
persuasive evidence supporting their position. “Attorneys’ argument is no
substitute for evidence.”16 Johnston v. IVAC Corp., 885 F.2d 1574, 1581
(Fed. Cir. 1989).
16 In response to the Examiner pointing out that Appellants’ arguments are
not supported by evidence, Appellants argue that “it is not an applicants’
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Finally, for the same reasons, we note but are not persuaded by
Appellants’ apparent argument that the claimed subject matter exhibits
unexpected results. (Appeal Br. 13.) Appellants have not shown that the
claimed subject matter are unexpected in view of the prior art.
Claim 13, 39, and 48
Appellants argue that claims 13, 39, and 48 are not obvious in view of
the cited prior art for essentially the same reasons as argued for claim 49,
namely, that the prior art does not “fairly suggest that PER.C6® cells
infected with Ad26 could be cultured in any manner,” including, e.g., in the
number of days claimed,17 to produce Ad26 virus particles having the
claimed unit productivity, yield, and/or infectious particle (VP/IU) ratio.
(Appeal Br. 17—18 (claim 48), 18—19 (claim 13), 19-20 (claim 39).) With
respect to claims 39 and 48, Appellants also argue, as they did with respect
to claim 49, that “no reason or motivation existed for a person of ordinary
skill in the art to transfer producer cells from a first production [profusion]
burden to demonstrate that an invention was non-obvious.” (Appeal Br. 17.)
We are not persuaded because, as discussed above, we find that the
Examiner has met the burden of presenting a prima facie case of
obviousness with respect to this limitation. Thus, “the burden of coming
forward with evidence or argument shifts to the applicant.” In re Oetiker,
977 F.2d 1443, 1445 (Fed. Cir. 1992).
17 Appellants did not make any specific arguments with regard to the
limitations relating to culturing time in claims 39, 48, and 49. In any event,
we agree with the Examiner that culturing time is a known result effective
variable in determining yield. (Ans. 6; see also, e.g., Crowley, Figs. 1—6
(describing viable cell density, cell growth, and productivity of IgGl
producing PER.C6® cells as a function of culturing time).) “[DJiscovery of
an optimum value of a result effective variable in a known process is
ordinarily within the skill of the art.” In re Boesch, 617 F.2d 272, 276
(CCPA 1980).
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bioreactor to a second production perfusion bioreactor, as claimed.” (Id. at
18 (claim 48), 19-20 (claim 39).) We are not persuaded for the reasons
already discussed above.
Claim 24
Appellants argue that claim 24 is not obvious in view of the cited
prior art for substantially the same reasons as claim 39 and further because
“the Examiner’s apparent conflation of this composition claim with the
pending method claims is insufficient to make out a proper prima facie case
of obviousness for this claim.” (Appeal Br. 20-21.) Appellants argue that
“[t]he patentability of a product cannot be equated with the patentability of a
process to produce that product.” (Id. at 21.)
We are not persuaded. We have already addressed Appellants’
arguments with respect to claim 39 above. As to Appellants’ argument
regarding the distinct nature of product versus process claims, we agree that
a product is not necessarily obvious merely because a process resulting in
the product is obvious. In this case, however, Havenga suggests
productivity of 105 VP rAd35 per cell with PER.C6® cells growing at 10
million cells ml'1 at the 101 scale (i.e., 1 x 1012 rAd35 VP/ml). (FF12.)
Havenga also teaches obtaining VP:p.f.u. ratio of 9.7 ±1.8 (i.e., VP/IU ratio
less than 30:1) when using rAd35-50rf6 vector on PER.C6® cells. (FF11.)
Moreover, while the examples in Havenga relate to rAd35, Bett provides a
reasoning for producing rAd26 (see, e.g., FF2, FF3), and Havenga teaches
that its method for enhancing replication and improving VP:IU ratio in
PER.C6® cells is likely to also work on subgroup D adenoviruses such as
rAd26 (FF13). Likewise, while Havenga does not specifically discuss
culturing PER.C6® cells in a suspension using a bioreactor comprising a
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perfusion system and culture medium, Crowley teaches a bioreactor
comprising an ATF perfusion system having a working volume of 4L (i.e.,
between 2L and 1000L) for culturing PER.C6® cells in culturing medium,
where maximum viable cell density of IgG-producing PER.C6® cells
reached an even greater maximum viable cell density of 100 x 106 cells/mL.
(FF19.)
Given all of the above, we find that the combination of Bett, Havenga
and Crowley renders claim 24 prima facie obvious, because the combination
would suggest to a skilled artisan to use a bioreactor having the claimed
working volume, perfusion system, culture medium, and PER.C6® cells to
produce rAd26 virus particles, wherein the reactor would reasonably be
expected to contain the claimed virus particle yield of at least 1 x 1012
VP/mL having the claimed VP/IU ratio.
Accordingly, we affirm the Examiner’s rejection of claim 13, 24, 39,
48, and 49. Claims 14—20, 22, 25, 26, 28, 31—38, and 41—47, which are not
separately argued, fall with claims 13, 24, and 39. See App. Br. 19, 20, 21;
37C.F.R. §41.37(c)(l)(iv).
II.
Issue
The Examiner has rejected claims 13—20, 22, 24—26, 28, 31—39, and
41—49 on the ground of nonstatutory obviousness-type double patenting as
being unpatentable over claims 1—3, 5, 6, 8—10, 12—14, 16, 18—20, 23—29,
32, and 35 of copending Application No. 13/126,978 (“’978 Application”).
The Examiner finds that the cited claims of the ’978 Application are similar
to the claims on appeal, except that the claims of the ’978 Application are
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directed towards methods of production for, and bioreactors comprising,
rAd35 rather than rAd26. (Ans. 7.)
Appellants argue claims 13—20, 22, 24—26, 28, 31—39, and 41—48
together. We, thus, limit our analysis to claims 13 and 49 as representative.
37 C.F.R. § 41.37(c)(l)(iv). Appellants do not appear to dispute the
Examiner’s finding regarding the scope of the ’978 Application claims.
(Appeal Br. 22.) Appellants contend, however, that the obviousness-type
double patenting rejection of claims 13 and 49 is “defective for the same
reason as is the rejection under 35 U.S.C. § 103(a),” i.e., that “it is not the
case that results obtained with one adenovirus serotype are able to be
analogized to a completely different serotype, such that the ordinarily skilled
person would have reasonably expected to recapitulate such results in the
new serotype.” {Id. at 22—23.) We are not persuaded for the reasons already
discussed above with respect to the obviousness rejection. Pfizer, 480 F.3d
at 1364 (explaining that “expectation of success need only be reasonable, not
absolute”).
SUMMARY
For the reasons above, we affirm the Examiner’s decision rejecting
claims 13-20, 22, 24-26, 28, 31-39, and 41^19.
TIME PERIOD FOR RESPONSE
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).
AFFIRMED
26