Ex Parte Craig et al

Board of Patent Appeals and Interferences

Sep 24, 2010

10112391 (B.P.A.I. Sep. 24, 2010)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte CHARLES H. CRAIG, HERBERT R. RADISCH, JR.
THOMAS TROZERA, DAVID M. KNAPP, TIMOTHY S. GIRTON, and
JONATHAN S. STINSON
____________

Appeal 2010-007318
Application 10/112,391
Technology Center 3700
____________

Before JENNIFER D. BAHR, STEFAN STAICOVICI, and
KEN B. BARRETT, Administrative Patent Judges.

STAICOVICI, Administrative Patent Judge.

DECISION ON APPEAL1

1 The two-month time period for filing an appeal or commencing a civil
action, as recited in 37 C.F.R. § 1.304, or for filing a request for rehearing,
as recited in 37 C.F.R. § 41.52, begins to run from the “MAIL DATE”
(paper delivery mode) or the “NOTIFICATION DATE” (electronic delivery
mode) shown on the PTOL-90A cover letter attached to this decision.

Appeal 2010-007318
Application 10/112,391

STATEMENT OF THE CASE
Charles H. Craig et al. (Appellants) appeal under 35 U.S.C. § 134
(2002) from the Examiner’s decision finally rejecting claims 1-10, 19-24,
and 33-38. Claims 11-18 and 25-32 have been canceled. Appellants’
representative presented oral argument on September 14, 2010. We have
jurisdiction over this appeal under 35 U.S.C. § 6 (2002).

THE INVENTION
Appellants’ invention relates to a stent made from a radiopaque
platinum enhanced alloy including approximately 11-18 wt. % chromium, 5-
12 wt. % nickel, 15 wt. % iron, and 2-50 wt. % platinum. Spec. 1:16-21 and
Spec. 5:21-6:2.
Claim 1 is representative of the claimed invention and reads as
follows:
1. A stent, comprising:

a body portion having an exterior surface defined
thereon, said body portion being expandable from a first
position, wherein said body portion is sized for insertion into a
lumen, to a second position, wherein at least a portion of said
stent is adapted to contact a lumen wall,

wherein the body portion is formed of a metallic alloy in
the form of a mixture of elements, the alloy including about 11
to about 18 percent by weight chromium, about 5 to about 12
percent by weight nickel, at least about 15 percent by weight
iron, and greater than 10 to about 50 percent by weight
platinum.

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THE REJECTIONS
The Examiner relies upon the following as evidence of
unpatentability:
Del Corso US 4,891,080 Jan. 2, 1990
Fischell US 5,607,442 Mar. 4, 1997
Tu US 6,077,298 Jun. 20, 2000
Cox US 6,273,911 B1 Aug. 14, 2001
Dang US 6,471,721 B1 Oct. 29, 2002
Nishikawa (as translated) JP 55-131157 Oct. 11, 1980

Appellants present additional evidence in the Declaration of Jonathan
S. Stinson (hereafter referred to as “Stinson Declaration”).
The following rejections are before us for review:
The Examiner rejected claims 1, 3, 4, 6, 19-22, 33, 34, 36, and
37 under 35 U.S.C. § 103(a) as unpatentable over Dang and Nishikawa
with evidentiary support from Tu and Fischell.
The Examiner rejected claims 7, 8, 10, 23, 24, 35, and 38 under
35 U.S.C. § 103(a) as unpatentable over Dang and Nishikawa with
evidentiary support from Tu, and Cox.
The Examiner rejected claims 2, 5, and 9 under 35 U.S.C. § 103(a) as
unpatentable over Dang, Nishikawa, and Tu with evidentiary support from
Cox, and Del Corso.

SUMMARY OF DECISION
We AFFIRM.

ANALYSIS
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Each of the Examiner’s rejections is based on the combined teachings
of Dang and Nishikawa. See Ans. 3, 5, and 6. Appellants do not argue
against each rejection separately but rather make a single argument against
the combination of Dang and Nishikawa. App. Br. 5. Specifically,
Appellants argue that because a stent and a wristwatch band experience
significantly different corrosion environments and mechanical stresses, “it
would not have been obvious to a person of ordinary skill in the art of stent
design to select the wristwatch band alloy of Nishikawa to produce a stent
regardless of the disclosures of Dang, Nishikawa, and/or Tu.” App. Br. 5.
See also, App. Br. 7.
We disagree with Appellants’ position for the following reasons.
Although we appreciate that a stent and a wristwatch band experience
different corrosion environments (internal of a human body for a stent and
external of the body for the wristwatch band), nonetheless, electrolytes
represent the main corrosive element for both environments. As noted by
the Examiner, and we agree, Fischell specifically teaches that stainless steel
stents are prone to electrolytic corrosion when placed in the blood stream.
Ans. 4. See also, Fischell, col. 2, ll. 54-67. We further agree with the
Examiner that the 316 L stainless steel wristwatch band of Nishikawa is
alloyed with platinum to improve corrosion resistance to electrolytes such
as sweat or seawater. Ans. 4. See also, Nishikawa, p. 3, l. 12. Furthermore,
even assuming arguendo that the stent of Dang is subjected to aqueous
corrosion, whereas the wristwatch band of Nishikawa is subjected to
atmospheric corrosion, as Appellants argue (App. Br. 7-8), Appellants’ own
evidence states that, “[a]tmospheric corrosion is an aqueous process.” ASM
Handbook, Volume 13A, Corrosion: Fundamentals, Testing, and Protection,
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Atmospheric Corrosion, Lucien Veleva and Russell D. Kane, p. 196, ASM
International (2003). Hence, we disagree with Appellants’ position that the
corrosion environment of Dang’s stent is “considerably different” from that
of Nishikawa’s wristwatch band. See App. Br. 7. Emphasis added.
With respect to Appellants’ argument regarding the mechanical
stresses exhibited by a stent and a wristwatch band, we agree with
Appellants that, “[a] stent experiences mechanical stresses that a wristwatch
band does not experience.” Id. We further agree with Appellants that
mechanical stresses initiate or amplify corrosion. Id. However, we note
that mechanical properties of a material are not solely dependent on the
composition of the material, as Appellants appear to contend. For example,
for the same material and the same mechanical loading an I-shaped beam
will exhibit mechanical properties different from a T-shaped beam. Hence,
we agree with the Examiner that when choosing a material for a stent, a
person of ordinary skill in the art of stent design would have to take into
consideration other factors in addition to the composition of the material,
such as size and shape of the stent. See Ans. 9. Furthermore, the platinum-
alloyed 316L stainless steel material of Nishikawa has the same composition
as Appellants’ claimed alloy, which Appellants have identified as being
suitable for making a stent. See Spec. 5:21-6:2. This is sufficient to
establish a prima facie case that Nishikawa’s platinum-alloyed 316L
stainless steel material is suitable for making a stent, so as to shift the burden
to Appellants to show that it is not. See In re King, 801 F.2d 1324, 1327
(Fed. Cir. 1986). Appellants have not come forth with any evidence to
satisfy that burden. Specifically, Appellants have not provided any evidence
to show that the addition of platinum to a 316L stainless steel material, as
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Application 10/112,391

taught by Nishikawa, would impair its mechanical properties. Nishikawa’s
platinum-alloyed 316L stainless steel material is merely the 316L stainless
steel material of Dang alloyed with platinum, which Dang teaches improves
radiopacity and Nishikawa teaches improves electrolytic corrosion
resistance.
Appellants further argue that, “[a]pplicants were not attempting to
find a material more corrosion resistant” than 316L stainless steel, which
is already recognized in the art as being sufficiently corrosion resistant
for a stent, but rather a material “having improved radiopacity,” while
maintaining mechanical and corrosion resistance. App. Br. 5. Although we
agree that 316L stainless steel is sufficiently corrosion resistant for a stent,
the problem addressed in Dang was insufficient radiopaque properties. Ans.
8. See also, Dang, col. 2, ll. 56-58 and col. 3, l. 25. Dang teaches that a
known method of improving radiopacity of a stent was to plate selected
portions of the stent with a radiopaque material. Id., col. 2, ll. 18-20.
However, if the plating did not cover all of the stent’s surfaces the stent was
subject to galvanic corrosion. Id., col. 2, ll. 33-35. Similarly, in Nishikawa,
the corrosion resistance of a plated wristwatch band was also poor because
of galvanic corrosion. Nishikawa, p. 1. However, Nishikawa’s platinum-
alloyed 316L stainless steel material improved galvanic corrosion resistance
of the plated wristwatch band. Id., p. 4. Hence, when the platinum-alloyed
316L stainless steel material of Nishikawa is used to make the stent of Dang,
as the Examiner proposes, both corrosion resistance and radiopaque
properties of the stent are improved.
For the above reasons, in view of the combined teachings of Dang and
Nishikawa, a person of ordinary skill in the art would have had a reasonable
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expectation that the platinum-alloyed 316L stainless steel material of
Nishikawa would be suitable for making a stent. Specifically, the combined
teachings of Dang and Nishikawa would have readily suggested to a person
of ordinary skill in the art that a platinum-alloyed 316L stainless steel
material would be advantageous for making a medical stent because it
provides: (1) improved electrolytic corrosion resistance, and (2) the
additional benefit of improved radiopacity.

The Stinson Declaration
Appellants argue that the Examiner has failed to present any evidence
to rebut the factual evidence submitted in the Stinson Declaration. App. Br.
6. In response, the Examiner takes the position that the Stinson Declaration
is “directed to opinion rather than factual evidence.” Ans. 9. Pointing to
various sources of extrinsic evidence (see App. Br. 16, Evidence Appendix),
the Stinson Declaration merely reiterates that (1) a stent and a wristwatch
band experience different corrosion environments and mechanical stresses
(Stinson Declaration, ¶¶ 5 and 6); (2) Nishikawa does not disclose that its
alloys have the mechanical and physical properties suitable for making a
stent (Stinson Declaration, ¶ 7); and (3) the inventors were concerned with
finding a material with improved radiopacity while maintaining mechanical
and corrosion resistance (Stinson Declaration, ¶ 8). However, all of these
statements essentially mirror the arguments presented in the Appeal Brief.
After weighing all of the evidence before us, we are convinced that the
evidence of obviousness of the claimed subject matter outweighs the
evidence of nonobviousness.
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Therefore, the rejections under 35 U.S.C. § 103(a) of claims 1, 3, 4, 6,
19-22, 33, 34, 36, and 37 as unpatentable over Dang and Nishikawa with
evidentiary support from Tu and Fischell; claims 7, 8, 10, 23, 24, 35, and 38
as unpatentable over Dang and Nishikawa with evidentiary support from Tu,
and Cox; and claims 2, 5, and 9 as unpatentable over Dang, Nishikawa, and
Tu with evidentiary support from Cox, and Del Corso are sustained.

SUMMARY
The decision of the Examiner to reject claims 1-10, 19-24, and 33-38
is affirmed.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a). See 37 C.F.R.
§ 1.136(a)(1)(iv) (2007).

AFFIRMED

JRG

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