Ex Parte Sikes et al

Patent Trial and Appeal Board

Jul 1, 2013

12133728 (P.T.A.B. Jul. 1, 2013)

UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
__________

Ex parte COURTNEY SIKES and MARK BODEN
__________

Appeal 2012-002872
Application 12/133,728
Technology Center 1600
__________

Before MELANIE L. McCOLLUM, JEFFREY N. FREDMAN, and
ULRIKE W. JENKS, Administrative Patent Judges.

FREDMAN, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal1 under 35 U.S.C. § 134 involving claims to an
implantable medical device having a block or graft copolymer. The
Examiner rejected the claims as obvious. We have jurisdiction under 35
U.S.C. § 6(b). We reverse.

1 Appellants identify the Real Party in Interest as Boston Scientific
Scimed, Inc. (see App. Br. 3).
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Application 12/133,728

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Statement of the Case
Background
“The present invention relates to the field of controlled, local delivery
of pharmacologically active agents, [and] to polymer compositions useful
therein” (Spec. 1, ll. 6-7).
The Claims2
Claims 17, 20-25, 27, and 28 are on appeal. Claim 17 is
representative and reads as follows:
17. An implantable medical device having a coating
thereon wherein the coating comprises a block or graft
copolymer that comprises at least a first block, a second
block different from the first block, and a third block,
wherein the first block is a poly(lactide-glycolide)
copolymer,
the second block is a member of the group consisting
of lactide-glycolide copolymer having a higher percentage
of lactide than the first block copolymer, polylactide
homopolymer, poly(trimethylene carbonate),
poly(caprolactone), poly(-butyro lactone), poly(-valero
lactone), and poly(tyrosine carbonate),
the first and second blocks are characterized by
respective degradation rates when the block copolymer is
placed in the body of a subject animal, the degradation rate
of the first block being greater than the degradation rate of
the second block, and
the third block being characterized by a degradation
rate when the block copolymer is placed in the body of a
subject animal that is different from the respective
degradation rates of the first and second blocks.

2 We note that pending claim 18 is not currently included in the
statement of rejection (see Advisory Action, mailed April 13,
2011).
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The issue
The Examiner rejected claims 17, 20-25, 27, and 28 under 35 U.S.C. §
103(a) as obvious over Hossainy3 and Trollsas4 (Ans. 4-5).
The Examiner finds that Houssainy teaches “a block copolymer that
comprise at least a first block and a second block different from the first
block wherein the first block is poly(lactide-glycolide) copolymer” (Ans. 4).
The Examiner finds that “Hossainy teaches that the PEA block copolymer
can be used in combination with a biocompatible polymer of which
poly(lactide-co-glycolide) is disclosed” (Ans. 4). The Examiner finds that
it would have been within the purview of one of ordinary
skill in the art to optimize the percentage of lactide units to
include higher lactide percentage in the second block to
obtain this release rate because as taught by Trollsas . . . an
increase in the lactide units can decrease the water-uptake
capacity of the polymer and decrease the dissolution rate of
the second block copolymer.

(Ans. 5). The Examiner finds that because “the second block would have a
higher percentage of lactide units (thereby decreasing degradation) drug
eluted from the second block would expectedly be released at a slower rate
when implanted into the body of a subject” (Ans. 5).
The issue with respect to this rejection is: Does the evidence of record
support the Examiner’s conclusion that Houssainy and Trollsas render claim
17 obvious?

3 Hossainy, S., US 2006/0142541 A1, published Jun. 29, 2006.
4 Trollsas et al., US 2009/0110711 A1, published Apr. 30, 2009.
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Findings of Fact
1. Hossainy teaches “polymers and combination of polymers for
coating stents and other implantable medical devices, where the polymers
forming the coatings are biologically compatible and absorbable” (Hossainy
1 ¶ 0009).
2. Hossainy teaches “a copolymer that includes a soft block (A)
which can be a poly(ester amide) (PEA) block (A) and another block (B).
The copolymer can be any of AB, ABA, and BAB type block copolymer.”
(Hossainy 1 ¶ 0010).
3. Hossainy teaches that the “PEA block copolymer described
herein can be used alone or in combination with a biocompatible
polymer . . . The biocompatible polymer can be any biocompatible polymer
known in the art . . . Representative examples of polymers that can be used
to coat an implantable device in accordance with the present invention
include, but are not limited to . . . poly(lactide-co-glycolide) . . . poly
(trimethylene carbonate)” (Hossainy 3 ¶ 0030).
4. Hossainy teaches that the “implantable device or the coating
may also include a bioactive agent. Exemplary bioactive agents include, but
are not limited to, paclitaxel . . . everolimus” (Houssainy 1 ¶ 0012).
5. Trollsas teaches “an implantable device that includes a
dissolvable coating or polymeric matrix. Upon implantation, the
physiological environment in the implantation site can dissolve away the
polymeric matrix via, for example, degradation of the polymer” (Trollsas 1 ¶
0014).
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6. Trollsas teaches that in “some embodiments, the dissolvable
coating comprises a poly(D,L-lactide-co-glycolide-b-ethylene glycol-b-D,L-
lactide-coglycolide) triblock copolymer (PLGA-PEG-PLGA) with D,L-
lactide/glycolide molar ratio ranging from 5/1 to 3/2 and molar
concentration of PEG ranging from 5 to 40 percents” (Trollsas 1 ¶ 0014).
7. Trollsas teaches that the “polymeric matrix can include a
bioactive agent such as a therapeutic substance or drug. . . . Some other
exemplary bioactive agents are paclitaxel . . . everolimus” (Trollsas 2
¶ 0017).
8. Trollsas teaches that
In the PLGA-PEG-PLGA triblock copolymer, the PEG
blocks dissolve quickly in an aqueous environment such as a
physiological environment and therefore impart
dissolvability to the polymer. In addition, the PLGA blocks
impart hydrophobicity to the polymer, and the PEG block
imparts hydrophilicity to the polymer. Therefore, by varying
the concentration of the PEG in the triblock copolymer, one
can make a PLGA-PEG-PLGA block polymer having an
optimal dissolution rate.

(Trollsas 3 ¶ 0038).
9. Trollsas teaches that “the PLGA-PEG-PLGA triblock
copolymer can be formed of PLGA and PEG blocks with varying molecular
weights” (Trollsas 4 ¶ 0039).
10. Trollsas teaches that
In selecting a proper range of molecular weight for the
PLGA block, the following factors are to be considered,
among other factors: (1) lactide (LA) units are generally
hydrophobic and thus an increase in the percentage of LA
units can decrease the water-uptake capacity of the polymer
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so as to decrease the dissolution rate of the polymer; (2) an
increase of the percentage of the PEG block in the polymer
will generally increase the water-uptake capacity of the
polymer so as to increase the dissolution rate of the polymer;
and (3) glycolide (GA) units provide a degradation rate
faster than lactide units.

(Trollsas 4 ¶ 0039).
11. Trollsas teaches that the “LA/GA ratio within a PLGA block
can also vary. For example, the LA/GA ratio can be from about 5/95, about
10/90 . . . Because the difference of rate of dissolution in LA and GA units, a
higher ratio of GA in the PLGA will generally generate a PLGA-PEG-
PLGA block copolymer with a higher rate of dissolution” (Trollsas 4
¶ 0040).
12. The Specification teaches that it “should be noted that the
characterization of the “first” and “second” blocks here does not indicate a
location or orientation within the polymer. For instance either the first block
or the [sic second] may be an end block, a mid-block, a side chain block, or
may have some other orientation within the block or graft copolymer
structure” (Spec. 5, ll. 15-18).
Principles of Law
“In proceedings before the Patent and Trademark Office, the
Examiner bears the burden of establishing a prima facie case of obviousness
based upon the prior art.” In re Fritch, 972 F.2d 1260, 1265 (Fed. Cir. 1992).
“[R]ejections on obviousness grounds cannot be sustained by mere
conclusory statements; instead, there must be some articulated reasoning
with some rational underpinning to support the legal conclusion of
obviousness.” KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 418 (2007).
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Analysis
Hossainy teaches an implantable medical device comprising a block
copolymer coating with three blocks (FF 1-2). Trollsas teaches an
implantable medical device comprising a block copolymer coating with
three blocks (FF 5-6) where varying the ratio of components in the block
copolymers alters their dissolution or degradation rates (FF 8-11). The
Specification teaches that the claims encompass any order of blocks (FF 12).
However, claim 17 also reasonably requires a block or graft
copolymer coating composed of three blocks with three different
compositions, expressly requiring “a first block, a second block different
from the first block” and a third block “characterized by a degradation
rate . . . that is different from the respective degradation rates of the first and
second blocks” (see Claim 17).
The Examiner does not identify a direct teaching in either Hossainy or
Trollsas to use a three block copolymer with three different degradation
rates. In all of the identified teachings in either Hossainy or Trollsas, the
polymer triblocks are identified as either ABA or BAB (FF 2) or PLGA-
PEG-PLGA (FF 6, 8), so that the triblocks are composed of two identical
blocks and a third different block.
The Examiner acknowledges that “although Trollsas does not
explicitly state that the ratio between the two PLGA blocks varies, this does
not mean that the ratios necessarily must be the same between the two
PLGA blocks” (Ans. 6). However, while the Examiner contends it would
have been obvious “that varying the ratio of each PLGA block within the
whole polymer would provide for different dissolution profiles” (Ans. 7),
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there is no evidence of record suggesting any alteration within the two
identical blocks would have been desirable, and both Hossainy and Trollsas
only suggest the use of identical end blocks (FF 2, 6). The Examiner has not
provided evidence that the prior art was aware of an “ABC” type polymer,
much less such an “ABC” polymer used in the context of a coating of an
implantable medical device nor that an “ABC” polymer was a predictable
variation. The Examiner has also not established that this is a situation
where there is a design need or market pressure to solve a problem not
already solved by Hossainy and Trollsas and that there were a finite number
of identified, predictable solutions. We also do not find that common sense
would necessarily provide a reason to alter the dissolution profile of one of
the two identical blocks, where the common sense is based solely on
Appellants’ disclosure.
Conclusion of Law
The evidence of record does not support the Examiner’s conclusion
that Houssainy and Trollsas render claim 17 obvious.
SUMMARY
In summary, we reverse the rejection of claims 17, 20-25, 27, and 28
under 35 U.S.C. § 103(a) as obvious over Hossainy and Trollsas.

REVERSED

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