Ex Parte Tan

Patent Trial and Appeal Board

Sep 2, 2014

10889432 (P.T.A.B. Sep. 2, 2014)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE PATENT TRIAL AND APPEAL BOARD
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Ex parte SHARON MI LYN TAN1
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Appeal 2012-004446
Application 10/889,432
Technology Center 3700
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Before ERIC B. GRIMES, MELANIE L. McCOLLUM, and JEFFREY N.
FREDMAN, Administrative Patent Judges.

McCOLLUM, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal under 35 U.S.C. § 134 involving claims to a
composite vascular graft. The Examiner has rejected the claims as obvious.
We have jurisdiction under 35 U.S.C. § 6(b). We affirm.
STATEMENT OF THE CASE
Claims 1–4, 6, 10–18, and 25–27 are on appeal (App. Br. 5).2 The
claims have not been argued separately and therefore stand or fall together.
37 C.F.R. § 41.37(c)(1)(vii). Claim 1 is representative and reads as follows:

1 Appellant identifies the real party in interest as Boston Scientific Scimed,
Inc., formerly known as Scimed Life Systems, Inc., which is a subsidiary of
Boston Scientific Corporation (App. Br. 3).
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1. A composite vascular graft comprising:
a porous, flexible tubular extruded, expanded polytetrafluoroethylene
graft member comprising nodes and fibrils;
a biodegradable, bioactive agent coating layer disposed over said graft
member; said coating layer including at least one bioactive agent; and
a biodegradable sheath disposed over said coating layer, said sheath
having a rigidity greater than said flexible tubular graft member; and being
biodegradable to expose said coating layer so as to re-establish the flexibility
of said tubular graft member.
Claims 1–4, 6, 10–18, and 25–27 stand rejected under 35 U.S.C.
§ 103(a) as obvious over Sirhan et al. (WO 02/056790 A2, July 25, 2002) in
view of Hill et al. (US 2003/0060871 A1, Mar. 27, 2003) (Ans. 4).
The Examiner relies on Sirhan for teaching
a composite vascular graft (see Figs. 2C-2N) comprising:
a flexible tubular graft member 16 . . . made from
expanded polytetrafluoroethylene . . . ;
a coating layer 40/46 (as shown in Figs 2F-2G, 2I, and
2K for example) comprising a biodegradable material . . . and
bioactive agent 28 disposed over said graft member 16; . . . and
a sheath 43/49/52 (see Figs 2F-2G, 2I, and 2K) made
from a biodegradable material . . . disposed over said coating
layer 40/46 (as shown in Figs 2F-2G, 2I, and 2K for example).
(Ans. 4 (emphasis omitted).) The Examiner finds that “Sirhan specifically
teaches the sheath to be made from polylactides, polyanhydrides,
polyvinylpyrolidone [sic], polyglycols, polycaprolactone, gelatin derivatives,
and combinations thereof” (id. at 4-5). However, the Examiner finds that

2 Claims 5 and 7–9 are also pending but have been withdrawn from
consideration (App. Br. 5).
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“Sirhan fails to explicitly teach the PTFE graft 16 to be extruded, porous,
and to comprise nodes and fibrils” (id. at 5 (emphasis omitted)).
The Examiner relies on Hill for teaching “that is known to make
vascular grafts from extruded porous tubes of PTFE, specifically from
porous expanded ePTFE having nodes and fibrils” (id.). The Examiner
concludes:
[I]t would have been obvious to one having ordinary skill in the
art at the time of the invention to modify the graft 16 of Sirhan
by constructing it from the ePTFE having nodes and fibrils, as
taught by Hill, in order to employ a well-known type of PTFE
that is commonly used to construct vascular grafts, and in order
to employ a material that has a tailorable pore size to achieve
desired properties of the graft.
(Id.)
ISSUE
Does the evidence support the Examiner’s position that Sirhan and
Hill suggest a biodegradable sheath having a rigidity greater than the flexible
tubular graft member?
FINDINGS OF FACT
1. The Specification states:
[The] prior art describes an antimicrobial vascular graft made
with a porous antimicrobial fabric formed by fibers which are
laid transverse to each other, and which define pores between
the fibers. The fibers may be of ePTFE. Ceramic particles are
bound to the fabric material, the particles including
antimicrobial metal cations thereon, which may be silver ions.
The ceramic particles are exteriorly exposed and may be bound
to the graft by a polymeric coating material, which may be a
biodegradable polymer. A disadvantage of this device is that
the biodegradable coating layer does not provide sufficient
rigidity during implantation for an outer graft layer.
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(Spec. ¶ 17.)
2. The Specification discloses that “the biodegradable sheath is
comprised of a material selected from, but not limited to, the following:
polylactides, polyanhydrides, polyvinyl alcohol, polyvinylpyrolidone [sic],
polyglycols, gelatin derivatives and combinations thereof” (id. at ¶ 60).
3. Sirhan “provides luminal prostheses, such as vascular stents and
grafts for reducing or inhibiting restenosis” (Sirhan 1: 5–6).
4. Sirhan discloses that “the device includes a structure and at
least one source of at least one therapeutic capable agent associated with the
structure” (id. at 5: 32–33).
5. Sirhan also discloses that “the source may further comprise[] a
rate-controlling element 43” (id. at 30: 3–4).
6. In addition, Sirhan discloses that the “rate-controlling element
may be formed of a non-degradable, partially degradable, substantially
degradable material, or a combination thereof” (id. at 13: 11–12).
7. Sirhan also discloses:
Suitable biodegradable rate-controlling element materials
include, but are not limited to, poly(lactic acid), poly(glycolic
acid) and copolymers, poly dioxanone, poly (ethyl glutamate),
poly (hydroxybutyrate), polyhydroxyvalerate and copolymers,
polycaprolactone, polyanhydride, poly(ortho esters); poly
(iminocarbonates), polycyanoacrylates, polyphosphazenes,
copolymers and other aliphatic polyesters, or suitable
copolymers thereof including copolymers of poly-L-lactic acid
and poly-e-caprolactone; mixtures, copolymers, and
combinations thereof.
(Id. at 13: 18–24.)
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8. In addition, Sirhan discloses: “The rate-controlling element
will typically have a total thickness in a range from about 10 nm to about
100 μm. The thickness may also range from about 50 nm to about 100 μm,
from about 100 nm to about 50 μm, or from about 100 nm to 10 μm.” (Id. at
15: 11–14).
9. Sirhan also discloses that the “expandable structure usually will
have a thickness in a range from about 0.025 mm to 2.0 mm, preferably from
about 0.05 mm to about 0.5 mm” (id. at 36: 30–31).
PRINCIPLES OF LAW
[I]t is elementary that the mere recitation of a newly
discovered function or property, inherently possessed by things
in the prior art, does not cause a claim drawn to those things to
distinguish over the prior art. Additionally, where the Patent
Office has reason to believe that a functional limitation asserted
to be critical for establishing novelty in the claimed subject
matter may, in fact, be an inherent characteristic of the prior art,
it possesses the authority to require the applicant to prove that
the subject matter shown to be in the prior art does not possess
the characteristic relied on.
In re Best, 562 F.2d 1252, 1254–55 (CCPA 1977). “An assertion of what
seems to follow from common experience is just attorney argument and not
the kind of factual evidence that is required to rebut a prima facie case of
obviousness.” In re Geisler, 116 F.3d 1465, 1470 (Fed. Cir. 1997).
ANALYSIS
Appellant does not dispute that Hill discloses the claimed expanded
polytetrafluoroethylene (ePTFE) graft member or that it would have been
obvious to include Hill’s ePTFE graft member in Sirhan’s device. Instead,
Appellant argues that “the combination fails to disclose or suggest a more
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rigid biodegradable sheath be employed with an ePTFE graft” (App. Br. 11).
We are not persuaded.
The Examiner relies on Sirhan’s rate controlling element for being a
sheath (Ans. 4; see also Finding of Fact (FF) 5). Sirhan discloses that the
“rate-controlling element may be formed of a non-degradable, partially
degradable, substantially degradable material, or a combination thereof”
(FF 6). In addition, Sirhan discloses that suitable biodegradable materials
include materials that may be used to form the claimed sheath (compare
FF 2 & 7). We conclude that the Examiner has set forth a prima facie case
that Sirhan suggests a biodegradable sheath that has a rigidity that is greater
than Hill’s ePTFE graft (Ans. 5).
Appellant argues:
[T]he thickness of [Sirhan’s] scaffold . . . is 0.25 mm [sic,
0.025 mm (FF 9)] to 2.0 mm while the thickness of the rate-
controlling element . . . is 1.0 nm [sic, 10 nm (FF 8)] to 100 μm
. . . which is significantly less than the thickness of the scaffold.
One of ordinary skill in the art would not be lead to believe that
such a thin coating is going to provide rigidity to the underlying
scaffold.
(App. Br. 13.) However, absent sufficient evidence to support the assertion
that a thin coating would not provide rigidity, we agree with the Examiner
that this argument is not persuasive (Ans. 10).
We note Appellant’s reliance on a teaching in the Specification of a
“biodegradable coating layer [that] does not provide sufficient rigidity
during implantation for an outer graft layer” (App. Br. 13 fn. 8; FF 1).
However, in the absence of any indication of what is in this coating layer,
how thick it is, and even whether or not it has a rigidity greater than the
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graft, we agree with the Examiner that this teaching is insufficient to
demonstrate that Sirhan fails to suggest a biodegradable sheath having a
rigidity greater than Hill’s ePTFE graft member (Ans. 10).
CONCLUSION
The evidence supports the Examiner’s position that Sirhan and Hill
suggest a biodegradable sheath having a rigidity greater than the flexible
tubular graft member. We therefore affirm the obviousness rejection.
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

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