Ex Parte Coffin

Board of Patent Appeals and Interferences

Mar 25, 2010

11333309 (B.P.A.I. Mar. 25, 2010)

UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________

Ex parte ROBERT S. COFFIN
__________

Appeal 2009-010733
Application 11/333,309
Technology Center 1600
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Decided: March 25, 2010
__________

Before ERIC GRIMES, RICHARD M. LEBOVITZ, and FRANCISCO C.
PRATS, Administrative Patent Judges.

PRATS, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal under 35 U.S.C. § 134 involving claims to a method
of stimulating an immune response. The Examiner has rejected the claims
as obvious.
We have jurisdiction under 35 U.S.C. § 6(b). We reverse.
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STATEMENT OF THE CASE
Claims 1-19 stand rejected and are on appeal (App. Br. 2). Claim 1,
the only independent claim, is representative and reads as follows:
1. A method of stimulating an immune response in a human
or animal subject, which method comprises administering to a
subject in need thereof an effective amount of an attenuated
herpes virus which:
(i) lacks a functional vhs gene;
(ii) lacks a functional gene encoding ICP47; and
(iii) comprises a functional UL43 gene such that dendritic
cells are infected with said virus.

The sole rejection before us for review is the Examiner's rejection of
claims 1-19 under 35 U.S.C. § 103(a) as being obvious in view of Krisky1
and Coffin2 (Ans. 3-6).
OBVIOUSNESS
ISSUE
The Examiner cites Krisky as disclosing an incompetent herpes
simplex 1 virus (HSV-1) having all of the features recited in claim 1 (Ans. 3-
4). The Examiner notes that Krisky’s virus also includes multiple
heterologous transgenes which could “function synergistically in tumor
destruction and vaccine gene therapy applications” (id. at 5 (citing Krisky,
abstract)). The Examiner also notes that “[e]xpression of multiple

1 D.M. Krisky et al., Development of herpes simplex virus replication-
defective multigene vectors for combination gene therapy applications, 5
GENE THERAPY 1517-1530 (1998).
2 R.S. Coffin et al., Pure populations of transduced primary human cells
can be produced using GFP expressing herpes virus vectors and flow
cytometry, 5 GENE THERAPY 718-722 (1998).
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transgenes was exhibited in primary human melanoma cells” when
transfected with the virus (id.).
The Examiner concedes, however, that “Krisky does not teach
administering the vector into dendritic cells or injecting tumour cells” and
cites Coffin to meet that deficiency (id.). The Examiner finds that Coffin
discloses that an HSV-1 vector “expressing multiple genes can transduce
human cells such as dendritic cells” (id.) and that “the HSV-1 vector system
can be used in dendritic cells and cancer immunotherapy by loading with
tumour antigens” (id. at 5-6 (citing Coffin 720, first col.)).
Based on these teachings, the Examiner concludes that an ordinary
artisan would have considered it obvious to use Krisky’s mutant HSV-1
vector “for treatment in human dendritic cells. A person of ordinary skill in
the art would have been motivated to use the multigene vector in dendritic
cells because Coffin teaches they are effective in dendritic cells, and
reasonably would have expected success because of the teaching of Krisky
and Coffin” (id. at 6).
Appellant contends that an ordinary artisan would not have had a
reasonable expectation or motivation to use Krisky’s vector to stimulate an
immune response in dendritic cells because it was known in the art that
“HSV inhibits signaling pathways involved in dendritic cell maturation.
Such signaling pathways are essential for the initiation of an immune
response” (App. Br. 4). Appellant cites Salio3 and Kruse4 in support of this
argument (id. at 4-5).

3 Mariolina Salio et al., Inhibition of dendritic cell maturation by herpes
simplex virus, 29 EUR. J. IMMUNOL. 3245-3253 (1999).
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Moreover, Appellant argues, the “Examples contained in Appellant’s
specification surprisingly demonstrate that an HSV strain lacking a
functional vhs gene enhances activation of dendritic cells compared to an
identical virus that does not lack the vhs gene” (id. at 5). Thus, Appellant
urges, this “was surprising at the time the invention was made in view of the
prior art which taught that inhibition of dendritic cell activation by HSV-1
was independent of vhs expression. Accordingly, the claimed invention is
not rendered obvious by Krisky in view of Coffin” (id. at 7).
In view of the positions advanced by Appellant and the Examiner, the
issues with respect to this rejection are (a) whether the evidence of record
supports the Examiner’s conclusion that an ordinary artisan would have
considered claim 1 prima facie obvious in view of Krisky and Coffin, and if
so (b) whether the experimental evidence advanced by Appellant shows that
the process recited in claim 1 produces an unexpected result sufficient to
overcome the Examiner’s showing of prima facie obviousness.
FINDINGS OF FACT (“FF”)
1. Krisky describes “the generation and characterization of replication
incompetent herpes simplex virus type 1 (HSV-1) vectors” (Krisky 1517).
2. It is undisputed that Krisky’s virus has the genomic makeup required
by claim 1.
3. Krisky’s virus “carr[ies] distinct and independently regulated
expression cassettes for five transgenes (hIL-2, hGM-CSF, hB7.1, HSV-tk
and lacZ or hIFNγ)” (Krisky 1517).

4 Monika Kruse et al., Mature Dendritic Cells Infected with Herpes Simplex
Virus Type 1 Exhibit Inhibited T-cell Stimulatory Capacity, 74 J. VIROL.
7127-7136 (2000)
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4. Krisky discloses that the “five transgenes [were] chosen for their
potential to synergize in tumor cell killing and induction of antitumor
immunity” (id. at 1518).
5. Krisky discloses that “[s]imultaneous expression of multiple
transgenes was obtained for up to 7 days in primary human melanoma cells
with peak expression at 2-3 days after infection” (id. at 1517; see also 1523
(Figure 3), describing secretion of cytokines from virally infected cells).
6. Krisky elaborates:
The vector background used in our work combines the features
of cell growth arrest and reduced cytotoxicity, making it
attractive for certain applications. For example, it may prove
advantageous to infect tumor cells in vivo with vectors that both
arrest tumor growth and secrete immunomodulatory cytokines
that enhance the recruitment of tumoricidal inflammatory cells
and responder T cells capable of developing tumor-specific
immunity.

(Id. at 1527.)
7. It is undisputed that Krisky did not infect dendritic cells with its virus.
8. Coffin discloses that “a green fluorescent protein (GFP) expressing
HSV1 vector can transduce two primary human cell types – quiescent
human CD34+ hematopoietic progenitor cells and dendritic cells – which are
both hard to transduce by other means” (Coffin 718).
9. Coffin discloses that when “GFP is expressed together with a second
gene (in this case lacZ) from a single virus, transduced GFP-positive . . .
dendritic cells can . . . be generated at an effective efficiency of 100% for the
second gene” (id.).
10. Coffin discloses:
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[T]he substitution of a ‘test’ gene for the lacZ can allow
experiments to be performed in these cell types with a
uniformly transduced population which could not reliably be
achieved by other means. For example, in the case of dendritic
cells, cancer immunotherapy by loading with tumor antigens
followed by return to the patient has often been considered . . . .

(Id. at 720.)
11. Salio discloses:
Maturation of dendritic cells (DC), leading to migration and
increased T cell stimulatory capacity, is essential for the
initiation of immune responses. This process is triggered by a
variety of stimuli, such as inflammatory cytokines, bacterial
and viral products. Using a recombinant disabled infectious
single cycle herpes simplex virus 1 (HSV-1) encoding green
fluorescent protein, we show that the infected DC are defective
in up-regulating co-stimulatory molecules, do not produce
cytokines, and do not acquire responsiveness to chemokines
required for migration to secondary lymphoid organs. These
results reveal yet another strategy used by HSV-1 to evade the
immune response, namely the inhibition of signaling pathways
involved in DC maturation.

(Salio 3245.)
12. Salio also observes that “[o]ur results are in agreement with those
from Hayward et al. who showed that inhibition of monocyte accessory
functions by HSV-1 was independent of vhs expression” (id. at 3250).
13. Kruse discloses:
Mature dendritic cells (DC) are the most potent antigen-
presenting cells within the entire immune system. Interference
with the function of these cells therefore constitutes a very
powerful mechanism for viruses to escape immune responses.
Several members of the Herpesviridae family have provided
examples of such escape strategies, including interference with
antigen presentation and production of homologous cytokines.
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In this study we investigated the infection of mature DC with
herpes simplex virus type 1 (HSV-1) and the way in which
infection alters the phenotype and function of mature DC.
Interestingly, the T-cell-stimulatory capacity of these DC was
strongly impaired. Furthermore, we demonstrated that HSV-1
leads to the specific degradation of CD83, a cell surface
molecule which is specifically upregulated during DC
maturation. These data indicate that HSV-1 has developed yet
another novel mechanism to escape immune responses.

(Kruse 7127.)
14. The Specification discloses that it was “surprisingly found that
disruption of the gene encoding the virion host shut-off protein (vhs) in HSV
vectors enables efficient dendritic cell activation to occur in HSV infected
cells” (Spec. 3).
15. In Example 1, Appellant measured the effects of lipopolysaccharide
activation on dendritic cells infected with three different HSV-1 viruses, and
on uninfected cells (id. at 21-24).
16. The three viruses used in Example 1 consisted of:
(a) “17+/pR20.5/UL43,” a virus that had RSV/lacZ/pA and
CMV/GFP/pA sequences inserted into the HSV-1 UL43 locus (id. at 18-
19));
(b) “1764/27-/4-/pR20.5/vhs,” a virus that had RSV/lacZ/pA and
CMV/GFP/pA sequences inserted into the HSV-1 vhs gene, the virus thus
being a strain “deleted for the genes encoding ICP4, ICP27 and ICP34.5, and
has inactivating mutations in the genes encoding vmw65 and vhs” (id. at
19); and
(c) “1764/27-/4-/pR19lacZ,” a virus constructed in the same manner
as virus (b) above, except that a lacZ cassette was “recombined into the
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latency associated transcript (LAT) region of virus strain 1764/27-/4- rather
than the pR20.5 cassette into vhs” (id.).
17. After activation of the dendritic cells with lipopolysaccharide (LPS),
the concentrations of the cytokines IL-6 and TNFα in the culture
supernatants was determined, with the following results:

(Id. at 22.)
18. As seen in Appellant’s table, upon stimulation with LPS, dendritic
cells infected with HSV-1 that lacked a functional vhs gene (“(b”) 1764/27-
/4-/pR20.5/vhs”) secreted several times as much IL-6 and TNFα than
uninfected cells or cells infected with HSV-1 that had a functional vhs gene.
19. Appellant’s Example 2 shows similar results (see Figure 3).
20. Appellant’s Example 3 describes the results of T-cell proliferation
assays using dendritic cells and T-cells from hepatitis B vaccinated and un-
vaccinated individuals (Spec. 25). Before the assays the dendritic cells were
infected with a virus containing a hepatitis B surface antigen (HBS-Ag)
expressing cassette inserted into the vhs gene, and were compared to results
obtained using untreated cells, cells treated with the HBS-Ag protein and
control vectors (id.).
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21. The results of the T-cell proliferation assays are shown in Figure 4,
reproduced below:

Figure 4[ ]shows the proliferative responses of T-cells
prepared from hepatitis-B vaccinated and un-vaccinated
individuals in response to HBS-Ag. Dendritic cells taken from
each individual were either untreated, mixed with recombinant
HBS-Ag protein (HBSAg*), infected with the control vector
(1764/27-/4-/pR20.5/vhs HBSAg) or infected with the vector
expressing HBS-Ag (1764127-/4-/pR20.5/vhs/HBS-Ag) before
mixing with the T cells.

(Spec. 5.)
22. The results are interpreted in the Specification as follows:
These experiments showed (Fig.[4]) that while HBS-Ag
recombinant protein and the control HSV vector could induce a
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small T-cell proliferative response in vaccinated individuals, the
HSV response probably indicating proliferation of T-cells
specific to HSV structural proteins, and the control vector
mixed with recombinant HBS-Ag could illicit [sic] a slightly
greater response, the HBS-Ag expressing vector gave a
significantly greater response than any of these. Thus following
delivery of HBS-Ag directly into DC using an HSV vector a
significant and specific T-cell proliferative response was
induced which did not occur following mixing with
recombinant antigen alone. HSV vectors with vhs inactivated
thus allow the delivery of antigen coding genes to DC such that
DC retain the ability to stimulate antigen specific T-cell
proliferative responses.

(Id. at 25-26.)
PRINCIPLES OF LAW
In KSR Int' l Co. v. Teleflex Inc., 550 U.S. 398 (2007), the Supreme
Court stated:
When there is a design need or market pressure to solve a
problem and there are a finite number of identified, predictable
solutions, a person of ordinary skill has good reason to pursue
the known options within his or her technical grasp. If this
leads to the anticipated success, it is likely the product not of
innovation but of ordinary skill and common sense. In that
instance the fact that a combination was obvious to try might
show that is was obvious under § 103.

Id. at 421.
The Court also reaffirmed that unexpected results can overcome a
prima facie case of obviousness. See id. at 416 (“The fact that the elements
worked together in an unexpected and fruitful manner supported the
conclusion that Adams’s design was not obvious to those skilled in the art.”)
(discussing United States v. Adams, 383 U.S. 39 (1966)).
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Thus, as the Federal Circuit has stated, “[m]ere improvement in
properties does not always suffice to show unexpected results. . . . [W]hen
an applicant demonstrates substantially improved results . . . and states that
the results were unexpected, this should suffice to establish unexpected
results in the absence of evidence to the contrary.” In re Soni, 54 F.3d 746,
751 (Fed. Cir. 1995).
ANALYSIS
We agree with the Examiner that, in view of the prior art of record, an
ordinary artisan would have considered claim 1 prima facie obvious over
Krisky and Coffin. We find, however, that the experimental evidence
presented in the Specification shows that the process recited in claim 1
produces a result that is sufficiently unexpected to overcome the Examiner’s
showing of prima facie obviousness.
We interpret claim 1 to require that dendritic cells are infected with
the recited attenuated herpes virus. As Appellant argues, both Salio and
Kruse disclose that HSV-1 disrupts dendritic cells’ immune responsiveness.
Thus, absent Coffin’s disclosure, an ordinary artisan might have been
dissuaded from attempting to generate an immune response by administering
HSV-1 in a manner that involved infection of dendritic cells (FF 11, 13).
However, as Coffin discloses, infection of dendritic cells with HSV-1 results
in expression of transgenes carried by the virus (FF 7, 8).
In view of Coffin’s disclosure that dendritic cells infected with HSV-1
express transgenes carried by the virus, we agree with the Examiner that an
ordinary artisan would have reasoned that infecting dendritic cells with
Krisky’s virus, which carried a synergistic combination of genes that were
expected to provide anti-tumor immunity (FF 1-5), would in fact have been a
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useful method of stimulating an immune response. We are therefore not
persuaded that an ordinary artisan would have failed to consider claim 1
prima facie obvious.
However, as noted above, Appellant has shown that infecting
dendritic cells with an HSV-1 that lacks a functional vhs gene results in a
significantly higher endogenous secretion of cytokines by the cells, when
compared to HSV-1 possessing a functional vhs gene (FF 15-19), and also
results in a significantly higher T-cell proliferation response when the vhs
gene-lacking virus expresses an antigen of interest (FF 20-22). The
Examiner points to no disclosure in the prior art, or other evidence,
suggesting that an ordinary artisan would have expected that infecting
dendritic cells with Krisky’s virus would have improved the cells’ immune
responsiveness in the manner shown in the Specification, much less to the
significant degree demonstrated in Appellant’s examples.
As stated above, “when an applicant demonstrates substantially
improved results . . . and states that the results were unexpected, this should
suffice to establish unexpected results in the absence of evidence to the
contrary.” In re Soni, 54 F.3d at 751.
Given the evidence presented by Appellant, Appellant’s assertion that
the showing was surprising (FF 14), and the fact that the Examiner points to
no evidence suggesting that an ordinary artisan would have expected
Appellant’s results, we find that Appellant has adequately rebutted the

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Examiner’s showing of prima facie obviousness. Accordingly, we reverse
the Examiner’s obviousness rejection of claim 1, and its dependents, over
Krisky and Coffin.

REVERSED

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