Ex Parte Schwarz

Patent Trial and Appeal Board

Nov 1, 2012

10934844 (P.T.A.B. Nov. 1, 2012)

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.
10/934,844 09/03/2004 Marlene C. Schwarz 03-578 (4010/86) 5936
27774 7590 11/01/2012
MAYER & WILLIAMS PC
251 NORTH AVENUE WEST
Suite 201
WESTFIELD, NJ 07090
EXAMINER
HELM, CARALYNNE E
ART UNIT PAPER NUMBER
1615
MAIL DATE DELIVERY MODE
11/01/2012 PAPER
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.
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
__________

Ex parte MARLENE C. SCHWARZ
__________

Appeal 2011-011404
Application 10/934,844
Technology Center 1600
__________

Before FRANCISCO C. PRATS, 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
therapeutic-agent-releasing medical device. The Examiner has rejected the
claims as obvious. We have jurisdiction under 35 U.S.C. § 6(b). We affirm.
STATEMENT OF THE CASE
The Specification discloses “a medical device that comprises a rate
controlling release region and a therapeutic agent” (Spec. ¶ [0004]). In
particular, the Specification discloses:
The release region comprises a biodisintegrable agent (which
can correspond, for example, to a therapeutic agent or to a non-
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Application 10/934,844

2
therapeutic agent) and a biostable low Tg polymer. Upon
contact of the medical device with a subject (e.g., upon
implantation or insertion of the device), the release region
becomes depleted, at least at its surface, with respect to the
biodisintegrable agent. The low Tg polymer selected naturally
migrates, at body temperature, to occupy at least a portion of
the volume that is created by the departure of the
biodisintegrable agent from the surface. This migration, or
consolidation, creates a rate controlling membrane/barrier for
therapeutic agent remaining within the device.
(Id.) The Specification also discloses that a “„low Tg polymer‟ is a polymer
which displays a glass transition temperature (Tg) . . . that is below ambient
temperature, more typically below 25°C, 0°C, -25°C, or even -50°C (id. at
¶ [0015]).
Claims 1, 5-7, 11-15, 17, 18, 20, 21, 24, 25, 28, and 29 are on appeal
(App. Br. 2).
1
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. A therapeutic-agent-releasing medical device comprising a rate
controlling release region that comprises a biodisintegrable agent and a
biostable low glass transition temperature polymer having a glass transition
temperature below -50°C, which is selected from alkylene homopolymers
and acrylate homopolymers, wherein upon contact of said medical device
with a subject, the release region becomes depleted with respect to the
biodisintegrable agent, and the low glass transition temperature polymer
migrates to occupy at least a portion of the volume that is created by the
departure of the biodisintegrable agent, thereby forming a barrier layer for
therapeutic agent remaining within the device, wherein said medical device
is a stent.

1
Claims 2-4, 8, 10, 16, 19, and 26 are also pending but have been withdrawn
from consideration (App. Br. 2).
Appeal 2011-011404
Application 10/934,844

3
Claims 1, 5-7, 11-15, 17, 18, 20, 21, 24, 25, 28, and 29 stand rejected
under 35 U.S.C. § 103(a) as obvious over Eury
2
in view of Berg,
3
Fearnot,
4

and Kamath,
5
as evidenced by Jiang
6
(Ans. 4).
7

The Examiner relies on Eury for teaching “a coating with a
therapeutic containing polymeric material for an intravascular stent,”
specifically, “a multi-layered coating that comprises a polymer, in
combination with a porosigen (biodisintegrable agent) that dissolves or
degrades when in contact with body fluids” (id. at 4-5). The Examiner finds
that Eury teaches “that the preferred means of combining the polymer,
porosigen, and therapeutic agent is via extrusion” and “that the polymers
utilized have a relatively low processing temperature and name[s] 40
o
C,
80
o
C, and 100
o
C as qualifying temperatures” (id. at 5). In particular, the
Examiner finds that “[p]oly(caprolactone), polyorthoesters, polyimino-
carbonates, polyphosphazenes, poly(L-lactic acid), and poly(DL-lactic acid)
are exemplified polymers” and that “[p]olymers other than those explicitly
named are also envisioned . . . as long as they are able to be processed at low
temperature” (id.).
The Examiner relies on Berg for teaching “stents with a drug
containing polymeric coating” and that “[p]oly(caprolactone),

2
Eury et al., US 5,605,696, Feb. 25, 1997.
3
Berg et al., US 7,419,696 B2, Sep. 2, 2008.
4
Fearnot et al., US 5,609,629, Mar. 11, 1997.
5
Kamath et al., US 6,335,029 B1, Jan. 1, 2002.
6
C.-Y. Jiang et al., The Use of Model Polyisobutylene Networks to Study
Strain-Induced Crystallization, 11 POLYMER BULLETIN 319-324 (1984).
7
Claims 9, 22, and 23 are also listed as rejected (Ans. 4). However, these
claims were canceled (App. Br. 2).
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Application 10/934,844

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polyorthoesters, polyiminocarbonates, polyphosphazenes, poly(L-lactic
acid), poly(DL-lactic acid), as well as polyisobutylene are named as suitable
polymers for such a coating” (id. at 6). The Examiner relies on Jiang as
evidence “that polyisobutylene has a melting temperature of 5
o
C” (id.). The
Examiner relies on Fearnot and Kamath for teaching features of dependent
claims (id.).
The Examiner finds:
Since polyisobutylene melts at 5
o
C, it would have been able to
be processed by an extruder at a temperature considered low by
Eury et al. (e.g. 100
o
C or less). Berg et al. demonstrate that the
polymers exemplified by Eury et al. function in the same drug
delivery capacity as polyisobutylene. It then would have been
obvious to one of ordinary skill in the art at the time of the
invention to select polyisobutylene as a low processing
temperature polymer for the coatings of Eury et al. since it was
functionally equivalent to those exemplified and met their
processing requirements.
(Id. at 6-7.) The Examiner also finds: “Appellant identifies polyisobutylene
as a polymer with a glass transition temperature below -50
o
C. . . . Since the
polyisobutylene and the biodisintegrable agent (porosigen) are the same as
that claimed, they must have the same properties (e.g. ability to migrate and
occupy volume left by departure of biodisintegrable agent).” (Id. at 7.)
FINDINGS OF FACT
1. Eury discloses “a polymeric material containing a therapeutic
drug, for application to a thin reinforcement or structural member of [a] stent
on at least one side, for carrying and releasing the therapeutic drug” (Eury,
col. 2, ll. 7-11).
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Application 10/934,844

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2. Eury also discloses that the “polymer coating can be formed to
include pores or to contain a material which will dissolve or degrade to form
pores in the polymeric material” (id. at col. 2, ll. 16-18).
3. In addition, Eury discloses:
In a preferred aspect of the method of the invention, the
polymeric material in which the therapeutic drug is
incorporated has a relatively low processing temperature, such
as polycaprolactone, having a processing temperature of
approximately 80° C., poly(ethylene-co-vinyl acetate) or
poly(vinyl acetate), having processing temperatures of
approximately 100° C., or silicone gum rubber,,having a
processing temperature of about 40° C., for example. Other
polymers having similar relatively low processing temperatures
may also be suitable. Other polymers which may be suitable
include non-degradable polymers capable of carrying and
delivering therapeutic drugs, and biodegradable, bioabsorbable
polymers capable of carrying and delivering therapeutic drugs,
such as poly-DL-lactic acid (DL-PLA), and poly-L-lactic acid
(L-PLA), polyorthoesters, polyiminocarbonates, aliphatic
polycarbonates, and polyphosphazenes.
(Id. at col. 4, ll. 37-54 (emphasis added).)
4. Berg discloses a medical device, particularly a stent, coated
with an overlayer, wherein the “overlayer, typically in the form of a porous
polymer, is in intimate contact with [a] therapeutic agent and allows [the
therapeutic agent] to be retained on the medical device” (Berg, col. 12,
ll. 31-42).
5. Berg also discloses:
In order to provide the coated stent . . . , a solution which
includes a solvent, a polymer dissolved in the solvent and a
therapeutic substance dispersed in the solvent is first prepared.
. . . The solution is applied to the stent and the solvent is
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Application 10/934,844

6
allowed to evaporate, thereby leaving on the stent surface a
coating of the polymer and the therapeutic substance.
(Id. at col. 12, l. 63, to col. 13, l. 28.)
6. In addition, Berg discloses:
The polymer chosen must be a polymer that is biocompatible
and minimizes irritation to the vessel wall when the stent is
implanted. The polymer may be either a biostable or a
bioabsorbable polymer depending on the desired rate of release
or the desired degree of polymer stability. . . . Bioabsorbable
polymers that could be used include poly(L-lactic acid),
polycaprolactone, . . . polyorthoester, . . . poly(D,L-lactic acid),
. . . poly(iminocarbonate), . . . [and] polyphosphazenes. . . .
Also, biostable polymers with a relatively low chronic tissue
response such as . . . silicones . . . could be used and other
polymers could also be used if they can be dissolved and cured
or polymerized on the stent such as . . . polyisobutylene[;] . . .
polyvinyl esters, such as polyvinyl acetate; [and] copolymers of
vinyl monomers with each other and olefins, such as . . .
ethylene-vinyl acetate copolymers.
(Id. at col. 13, l. 42, to col. 14, l. 8 (emphasis added).)
7. Polyisobutylene has a Tg of -73°C (Spec. ¶ [0025] & ¶ [0019]).
8. Noting that polyisobutylene melts at 5°C (Jiang 320), the
Examiner finds that “it would have been able to be processed by an extruder
at a temperature considered low by Eury et al. (e.g. 100
o
C or less)” (Ans. 6).
ANALYSIS
In view of the foregoing findings of fact, we conclude that the
Examiner has set forth a prima facie case that it would have been obvious to
use polyisobutylene, as disclosed in Berg, as the polymeric material of Eury
and that the resulting product would meet the requirements of claim 1. “The
combination of familiar elements according to known methods is likely to be
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7
obvious when it does no more than yield predictable results.” KSR Int’l Co.
v. Teleflex Inc., 550 U.S. 398, 416 (2007).
Appellant argues, however, that, unlike the processing temperatures
taught in Eury, the “melting temperature of polyisobutylene (5°C) given in
Jiang . . . is below room and body temperature and thus quantitatively
different from those of Eury et al., at least for medical device applications”
(App. Br. 4). Relying of Oppanol,
8
Appellant also argues “that the ability of
polyisobutylene to naturally migrate at body temperature can be readily
appreciated from the fact that polyisobutylene is commonly used in making
chewing gum” (id.). Thus, Appellant argues:
It would be utterly counterintuitive for one of skill in the art to
take a device like that of Eury et al., where pores are made
using a porosigen to create a porous membrane, and then
modify that device to create a device like that claimed in which
the polymer migrates to occupy at least a portion of the volume
that is created by the departure of the biodisintegrable agent,
thereby forming a barrier layer for therapeutic agent remaining
within the device. In other words, the modification of Eury et
al. proposed by the Examiner would result in a device in which
the porous membrane desired by Eury et al. would be destroyed
by polymer migration and barrier formation.
(Id. at 4-5.) We are not persuaded.
“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). Here, Appellant presents attorney argument indicating that
it would be “counterintuitive” to use polyisobutylene in Eury‟s stent coating

8
BASF, OPPANOL® POLYISOBUTYLENES PIB FOR CHEWING GUM (© 2007).
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Application 10/934,844

8
(App. Br. 4). However, we conclude that Appellant has not provided
sufficient evidence to support this position. Appellant does refer to
Oppanol, which states that “BASF‟s Oppanol® Polyisobutylenes are
excellent gum base ingredients because they are . . . [, among other things,
c]hewable even at low temperatures.” However, even if we assume that
Oppanol is prior art, we do not agree that this evidence is sufficient to
demonstrate that it would not have been obvious to use polyisobutylene, as
described in Berg, in Eury‟s stent coating.
Moreover, the Examiner finds:
Berg . . . explicitly teach[es] polyethylene as a polymer that is
particularly well suited as a porous coating on their implantable
medical device (see column 3 line 62). The most agreed upon
value for the glass transition temperature of polyethylene as
tabulated by the Polymer Handbook
9
is -125
o
C while that for
polyisobutylene is -73
o
C.
(Ans. 9.) Given this, the Examiner concludes that “there is no reason why
the artisan of ordinary skill in the art would conclude that a polyisobutylene
coating in Eury et al. would yield an inferior or less suitable porous coating
upon implantation due to its low glass transition temperature or ability to
migrate as appellant asserts” (id. at 10). Appellant has not adequately
explained why this position is in error.

CONCLUSION
The preponderance of evidence on this record supports the
Examiner‟s conclusion that representative claim 1 would have been obvious.
We therefore affirm the obviousness rejection.

9
POLYMER HANDBOOK 206 (J. Brandrup et al. eds., 4th ed. 1999).
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Application 10/934,844

9
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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