Ex Parte Richard et al

Patent Trial and Appeal Board

Mar 20, 2015

10632061 (P.T.A.B. Mar. 20, 2015)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE PATENT TRIAL AND APPEAL BOARD
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Ex parte ROBERT E. RICHARD and MARLENE C. SCHWARZ
1

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Appeal 2012-008747
Application 10/632,061
Technology Center 1600
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Before DEMETRA J. MILLS, ERIC B. GRIMES, and ULRIKE W. JENKS,
Administrative Patent Judges.

GRIMES, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal under 35 U.S.C. § 134 involving claims to a medical
device, which have been rejected as obvious. We have jurisdiction under 35
U.S.C. § 6(b).
We reverse.

1
According to Appellants, the Real Party in Interest is Boston Scientific
Scimed, Inc. (Appeal Br. 2.)
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Application 10/632,061

2
STATEMENT OF THE CASE
The Specification discloses “implantable or insertable medical devices
in which acrylic copolymers are used to control delivery of one or more
therapeutic agents.” (Spec. 1 ¶ 1.) The devices are said to have the
advantage, among others, of being “relatively resistant to the effects of
radiation sterilization.” (Id. at 4 ¶ 20.)
Claims 1–9, 11–20, and 23–27 are on appeal. Claim 1 is illustrative
and reads as follows:
1. An implantable or insertable medical device comprising (a) a
therapeutic agent and (b) a polymeric release region that controls the release
of said therapeutic agent upon administration to a patient, said polymeric
release region comprising an acrylic graft_copolymer which is a block
copolymer comprising (i) a rubbery block of rubbery acrylic units and (ii) a
hard block of hard units.

Claim 14, the only other independent claim, includes all of the
limitations of claim 1, and further limits the composition of the rubbery
block of the block copolymer.
DISCUSSION
The Examiner has rejected claims 1–7, 9, 11–20, and 23–27 under 35
U.S.C. § 103(a) as obvious based on Pinchuk,
2
Ruckenstein,
3
Hossainy,
4
and
Reference Polymer Properties (RPP).
5
(Ans. 5.) The Examiner rejected
claim 8 under 35 U.S.C. § 103(a) as obvious based on the same references,

2
Pinchuk et al., US 2002/0107330 A1, Aug. 8, 2002.
3
Ruckenstein et al., WO 00/59968, Oct. 12, 2000.
4
Hossainy et al., US 2001/0014717 A1, Aug. 16, 2001.
5
Reference: Polymer Properties, http://www.sigmaaldrich.com/img/assets/
3900/Thermal_Transitions_of_Homopolymers.pdf.
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Application 10/632,061

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further combined with Williams.
6
(Ans. 9.) The same issue is dispositive
for both rejections.
The Examiner finds that Pinchuk discloses a stent comprising a
therapeutic agent-releasing block copolymer that comprises elastomeric
blocks and thermoplastic blocks. (Ans. 5–6.) The Examiner equates the
elastomeric and thermoplastic blocks to the rubbery and hard blocks,
respectively, of the claims. (Id. at 6.) The Examiner finds that Pinchuk does
not disclose graft copolymers, but Ruckenstein does. (Id. at 6–7.)
The Examiner also finds that Pinchuk does not disclose rubbery
blocks of rubbery acrylic units. (Id. at 6.) The Examiner finds that Hossainy
discloses drug-delivering coatings for stents, and that “[t]he device can be
coated with a layer containing an acrylate polymer such as methyl acrylate
(¶ 36) (claim 16) and a therapeutic agent.” (Id. at 7.) The Examiner
concludes that it would have been obvious
to modify the insertable or implantable medical device
containing elastomeric and thermoplastic block copolymers as
described in the Pinchuk patent by using poly(methyl acrylate)
as the elastomeric polymer from Hossainy since it is suitable as
a coating for drug-releasing implantable devices (see Hossainy).
Poly(methyl acrylate) is elastomeric.
(Id. at 8.) The Examiner cites RPP as evidence that poly(methyl acrylate)
has a glass transition temperature of 10° C and therefore meets the
Specification’s definition of a rubbery unit. (Id.; cf. Spec. 6 ¶ 31.)
Appellants argue, among other things, that “just because Hossainy
teaches that poly(methyl acrylate) may be suitable as a coating material,
does not mean that it may [be] suitable for use as a block within a block

6
Williams, US 6,514,515 B1, Feb. 4, 2003.
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Application 10/632,061

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copolymer.” (Appeal Br. 5.) Appellants argue that “Hossainy does not
teach or suggest that poly(methyl acrylate) is a rubbery polymer,” and that
“Hossainy simply does not teach or suggest that a block of the methyl
acrylate units would be suitable as a block in a block copolymer, much less
an elastomeric block in a copolymer like that claimed in Pinchuk.” (Id.)
Appellants argue that “[i]t is only through hindsight improperly gained from
the present disclosure that the fact that the Tg of poly(methyl acrylate) is
below ambient temperature, and is thus rubbery, is of any significance.”
(Reply Br. 6.)
We agree with Appellants that the cited evidence does not support the
Examiner’s conclusion that it would have been obvious to include a
poly(methyl acrylate) block as the elastomeric block in Pinchuk’s block
copolymer. Pinchuk discloses a drug-delivery composition comprising a
block copolymer comprising elastomeric blocks and thermoplastic blocks.
(Pinchuk 1 ¶ 4.) The elastomeric blocks are preferably polyolefin blocks,
even more preferably polyisobutylene blocks. (Id. at 1 ¶ 7.)
Hossainy discloses a stent coating “having a reservoir region carrying
an active ingredient, e.g., actinomycin D or taxol. A primer region, free
from any active ingredients, can be disposed between the reservoir region
and the surface of the prosthesis.” (Hossainy 2 ¶ 14.) “The primer can
provide an adhesive tie layer between the surface of the implantable device
and the reservoir region.” (Id. at 2 ¶ 15.)
Hossainy discloses that polymers suitable for the primer region
“should have a high capacity of adherence to the surface of an implantable
device, such as a metallic surface of a stent.” (Id. at 3 ¶ 32.) More
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specifically, “polymeric materials with polar substituents and cationic
groups can adhere to the surface. Representative examples of suitable
polymeric material include . . . acrylates.” (Id.) “Representative examples
of acrylates include copolymers of ethyl acrylate, methyl acrylate,” etc. (Id.
at 3 ¶ 36.)
The Examiner concludes that it would have been obvious to use
poly(methyl acrylate) as the elastomeric block in Pinchuk’s block copolymer
because RPP shows that poly(methyl acrylate) has a glass transition
temperature (Tg) of 10° C and Appellants’ Specification defines rubbery
acrylic units as those having a Tg that is below ambient temperature for the
corresponding homopolymer.
We agree with Appellants, however, that this reasoning is flawed,
because it depends on the Specification to provide evidence that a person of
ordinary skill in the art would have recognized poly(methyl acetate) as being
suitable for use in Pinchuk’s elastomeric blocks. That is, Pinchuk discloses
polyolefin blocks to be preferred elastomeric blocks, and Hossainy discloses
that poly(methyl acrylate) is suitable for its primer layer because it will
adhere to the metallic surface of a stent.
The only evidence linking poly(methyl acrylate) with the elastomeric
properties desired by Pinchuk is derived from the Specification’s teaching
that glass transition temperature can be used as an indicator of whether
acrylic units are rubbery. The Examiner has not pointed to evidence in the
prior art showing that a skilled worker would have recognized Hossainy’s
poly(methyl acrylate) to be suitable for use in the elastomeric blocks of
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Pinchuk’s copolymer. We therefore agree with Appellants that the rejection
depends on improper hindsight.
We reverse the rejection of claims 1–7, 9, 11–20, and 23–27 under 35
U.S.C. § 103(a) based on Pinchuk, Ruckenstein, Hossainy, and RPP. The
Examiner has not pointed to any teaching in Williams that makes up for the
deficiency discussed above. We therefore reverse the rejection of claim 8
under 35 U.S.C. § 103(a) based on Pinchuk, Ruckenstein, Hossainy, RPP,
and Williams.

REVERSED

JRG