Ex Parte Lin

Patent Trial and Appeal Board

May 20, 2016

13302325 (P.T.A.B. May. 20, 2016)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR
13/302,325 11/22/2011 Jing Lin
71331 7590 05/24/2016
NIXON PEABODY LLP
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
ATTORNEY DOCKET NO. CONFIRMATION NO.
06DC001.l 1066
EXAMINER
70 West Madison, Suite 3500 RUFO, LOUIS J
CHICAGO, IL 60602
ART UNIT PAPER NUMBER
1759
NOTIFICATION DATE DELIVERY MODE
05/24/2016 ELECTRONIC
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.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address( es):
docketingchicago@nixonpeabody.com
ipairlink@nixonpeabody.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte JING LIN 1
Appeal2014-000406
Application 13/302,325
Technology Center 1700
Heard: February 29, 20162
Before JAMES C. HOUSEL, N. WHITNEY WILSON, and
CHRISTOPHER L. OGDEN, Administrative Patent Judges.
HOUSEL, Administrative Patent Judge.
DECISION ON APPEAL 3
Pursuant to 35 U.S.C. § 134(a), Appellant appeals from the
Examiner's decision finally rejecting claims 16-24 and 73-83 under 35
1 Appellant identifies the real party in interest as Bayer Healthcare LLC.
Appeal Br. 2.
2 The record includes a transcript of the oral hearing.
3 Our decision refers to Appellant's Specification filed November 22, 2011,
Appellant's Appeal Brief (Appeal Br.) filed May 22, 2013, the Examiner's
Answer (Ans.) mailed July 31, 2013, and Appellants' Reply Brief (Reply
Br.) filed September 23, 2013.
Appeal2014-000406
Application 13/302,325
U.S.C. § 103(a) as unpatentable over Cai '5374 in view of Cai '441 5 and
Lau, 6 and adding Bhullar7 to this combination against claim 23. 8 We have
jurisdiction over the appeal under 35 U.S.C. § 6(b ).
We REVERSE.
STATEMENT OF THE CASE
The invention on appeal relates to a method for correcting the effect
of oxygen in determining the concentration of an analyte in a test fluid.
Spec. i-f 1. Appellant discloses that in measuring particular analytes, e.g.
glucose, certain reacting reagents, e.g. glucose oxidase, are sensitive to the
level of oxygen in the test fluid, e.g. blood. Spec. i-f 5. According to
Appellant the effect of oxygen on the determined glucose concentration in a
blood sample using glucose oxidase may be as great as 20%. Id. To correct
for this oxygen effect, Appellant discloses use of a test sensor having first
and second working electrodes, and a counter electrode, with the first
working electrode having the analyte oxidase, a mediator, and peroxidase,
and the second working electrode includes the analyte oxidase and the
mediator. Spec. i-f 10. The method includes steps of measuring a first
current from the first working electrode and a second current from the
4 Cai et al., US 2006/0278537 Al, published December 14, 2006 ("Cai
'537").
5 Cai et al., US 6,767,441 Bl, issued July 27, 2004 ("Cai '441").
6 Lau et al., WO 01/00865 A2, published January 4, 2001 ("Lau").
7 Bhullar et al., US 6,767,440 Bl, issued July 27, 2004 ("Bhullar").
8 The Examiner also repeated the§ 103 rejection of claims 84--91. Ans. 10.
However, as Appellant notes, claims 84--91 have been cancelled and are not
before us on appeal. Appeal Br. 5.
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Application 13/302,325
second working electrode, and then determining the concentration of the
analyte using both current measurements. Id.
Appellant discloses, in one embodiment for correcting the oxygen
effect in a glucose determination, the following series of reactions that take
place on the test sensor, using glucose oxidase (GO) reagent and
ferricyanide as the mediator:
(Equation 1) glucose + GO (ox) ---+ gluconic acid+ GO (red)
(Equation 2) ferricyanide +GO (red)---+ ferrocyanide +GO (ox)
(Equation 3) 02 +GO (red)---+ H202 +GO (ox)
(Equation 4) peroxidase (red)+ H202---+ peroxidase (ox)+ H20
(Equation 5) peroxidase (ox)+ ferrocyanide---+ peroxidase (red)+
ferri cyanide;
wherein Equations 1-5 show the reactions that occur on the first working
electrode, and Equations 1-3 only show the reactions that occur on the
second working eiectrode. Spec. iii! 50-51 and 54. The amount of
ferrocyanide generated in the reaction of Equation 2 is directly proportional
to the glucose concentration in the fluid sample. Id. However, the reaction
of Equation 3 shows that oxygen competes with the oxidized mediator,
leading to less reduced mediator and, therefore, a lower glucose reading.
Spec. i-f 52. According to Appellant, adding peroxidase to the first working
electrode corrects for this oxygen effect such that the amount of reduced
mediator consumed in Equation 5 is proportional to the amount of H20 2 and,
therefore, the amount of 02 present in the sample. Spec. i-f 53. Appellant
then discloses that the corrected measured current can then be calculated:
(Equation 6) Corrected measured current= 2i- i',
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Appeal2014-000406
Application 13/302,325
wherein i = the measured current from the second working electrode,
and
i' = the measured current from the first working electrode. Spec. 54.
Claim 16, reproduced below from the Claims Appendix to Appellant's
Appeal Brief, is illustrative of the subject matter on appeal. The limitations
at issue are italicized:
16. A method for correcting the oxygen effect in determining the
concentration of glucose in a fluid using an electrochemical test
sensor, the method comprising the acts of:
providing a test sensor, the test sensor comprising a base, first
and second working electrodes, and a counter electrode, the first
working electrode including glucose oxidase, an oxidized form of a
mediator and peroxidase, the second working electrode including
glucose oxidase and the oxidized form of the mediator, the first
working electrode, the second working electrode and the counter
electrode being adjacent to the base;
contacting the test sensor to a meter to form an electrical
connection;
piacing the fluid on the test sensor;
measuring a first current from the first working electrode from
the reduced form of the mediator;
measuring a second current from the second working electrode
from the reduced form of the mediator; and
determining the concentration of glucose and correcting for the
oxygen effect by using the first current measurement and the second
current measurement.
Claims Appendix, Appeal Br. Al.
Similarly, independent claim 73 recites a method for correcting for the
oxygen effect in determining the glucose concentration in a fluid.
Additionally, independent claim 81 recites a similar method where the
analyte concentration being determined is cholesterol rather than glucose.
Finally, independent claim 83 recites a similar method where the analyte
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Application 13/302,325
concentration being determined is at least one of lactate, pyruvate or
xanthine. In each of these independent claims, the first and second working
electrodes each include the oxidized form of the mediator.
ANALYSIS
It is undisputed on this record that Cai '5 3 7 as modified by Cai '441
teaches the methods as claimed in each of the independent claims except the
provision of the oxidized form of the mediator in both the first and second
working electrodes such that the measurement of the current from the first
working electrode is from the reduced form of the mediator. Compare
Appeal Br. 9--10 with Ans. 4--7; see also Brown Declaration,9 i-f 9.
For this feature, the Examiner found Lau discloses an amperometric
sensor measuring the same chemical reaction as Cai '537, wherein the
reduced form of the mediator that is provided to interact with the hydrogen
peroxide is derived from the proportionai amount of giucose oxidase that
reacts with glucose. Ans. 7, citing Lau's equations 1 and 2 on pp. 1 and 3, 11.
18-20. The Examiner found Lau's equation 2 provides the oxidized form of
the mediator, and further that Lau specifies that the reduced form of the
mediator can be detected at a potential of about -400 m V in order to reduce
the oxidation of common interferents. Ans. 7, citing Lau, p. 2, 11. 20-22.
The Examiner concluded it would have been obvious to have replaced the
reduced form of the mediator in Cai '537, as modified by Cai '441, with
Lau's oxidized form "because the use of the oxidized form of the mediator
9 Declaration of Daniel V. Brown under 37 C.F.R. § 1.132, filed February
25, 2013.
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Application 13/302,325
allows the electrochemical detection to be performed at an appropriate
voltage to reduce oxidation of common interferents. Ans. 7. The Examiner
further reasoned that doing so would provide an amount of the reduced form
of the mediator needed to react with the hydrogen peroxide proportional to
the amount of glucose and "give an effective overall chemical reaction
scheme as described in the instant specification." Id. Further, the Examiner
found the prior art recognized that the mediator may be in either reduced or
oxidized form in a reaction layer and it would have been obvious to one of
ordinary skill in the art to select the appropriate form for the mediator. Ans.
7-8, citing MPEP 2143 B. 10
Appellant argues the combination of Cai '537 as modified by Cai '441
with Lau is improper because Cai '5 3 7 measures oxygen directly by using
an oxygen sensor including an oxidase, a reduced form of a mediator, and a
peroxidase, such that only the glucose sensor includes the oxidized form of
the mediator. Appeal Br. 8-10. Appellant also argues that, unlike Cai '537,
Lau provides a reduced form of the mediator, just as taught in Cai '537, and
measures the oxidized form of the mediator. Reply Br. 6. Moreover,
Appellant notes that Lau discloses a sensor that relies on reaction between a
mediator and hydrogen peroxide, where the peroxide is the analyte to be
detected or is the product of an enzyme-analyte reaction. Appeal Br. 11.
Appellant asserts that Lau's sensor solves the problems of unstable
mediators and oxidation of reduced forms of the mediator also oxidizes
interferents. Id. Appellant argues that Lau does not disclose any problem
with, nor solution for, the oxygen effect. Appeal Br. 12. As such, Appellant
10 Manual of Patent Examining Practice, Chapter 2100, Section 2143 B.
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Application 13/302,325
contends that one of ordinary skill in the art would not modify Cai '5 3 7 to
provide an oxidized form of the mediator on both sensors.
Appellant's arguments are persuasive of reversible error in the
Examiner's rejection. Although the Examiner found that both forms of the
mediator are ultimately utilized in an electrochemical reaction, the Examiner
does not explain why this finding supports the conclusion that use of either
form of the mediator on the sensors would have been obvious to one of
ordinary skill in the art. Cai '537 teaches reaction equations yielding the
oxidized form of the mediator, ferricyanide, which is capable of being
reduced electrochemically when a potential is applied to the sensor thereby
providing a current signal that is related to the combined glucose and oxygen
concentration. Cai '537 i-fi-121 and 30. Cai '537 further provides an oxygen
sensor using the reduced form of the mediator for detecting the oxygen
concentration which is then used to correct for the oxygen effect thereby
providing the glucose concentration. Cai '537 if 31. Unlike Cai '537, as
Appellant contends, Lau teaches use of the oxidized form of the mediator
only for the detection of glucose concentration without correction for
oxygen present in the sample. The Examiner does not explain why one of
ordinary skill in the art would have used Lau's teaching of detecting an
analyte using the oxidized form of a mediator to modify Cai '5 3 7 's oxygen
reagent matrix sensor corresponding to electrode area WI. Indeed, Cai
'537's oxidase-based analyte reagent loaded to electrode area W2 includes
the oxidized form of the mediator and corresponds to the analyte detection
of Lau. Thus, as Appellant argues, there is no suggestion in Lau for
modifying the oxygen reagent matrix of Cai '537.
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Application 13/302,325
The Examiner has the initial burden of establishing a prima facie case
of obviousness. See In re Piasecki, 745 F.2d 1468, 1472 (Fed. Cir. 1984); In
re Rinehart, 531F.2d1048, 1051(CCPA1976). Meeting that burden
requires establishing that the applied prior art would have provided one of
ordinary skill in the art with an apparent reason to modify the prior art to
arrive at the claimed invention. See KSR Int 'l Co. v. Teleflex Inc., 550 U.S.
398, 418 (2007). On this record, the Examiner has not established any basis
for modifying Cai '537's oxygen reagent matrix applied to working
electrode area WI with an oxidized form of the mediator as required by each
of Appellant's claims. Absent such a basis, the Examiner's conclusion lacks
sufficient rational underpinning. In re Kahn, 441F.3d977, 988 (Fed. Cir.
2006) ("[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."), quoted with approval in KSR, 550 U.S. at 418. Under these
circumstances, we cannot conclude that the Examiner has met the minimum
threshold of establishing obviousness under 35 U.S.C. § 103(a). See In re
Oetiker, 977 F.2d 1443, 1445 (Fed. Cir. 1992).
The Examiner does not rely on Bhullar to remedy the deficiencies in
the combination of Cai '537, Cai '441 and Lau discussed above.
Accordingly, we reverse the Examiner's prior art rejections of claims 16-24
and 73-83 under 35 U.S.C. § 103(a) for the reasons given above and
presented by Appellant.
DECISION
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Application 13/302,325
Upon consideration of the record, and for the reasons given above and
in the Appeal and Reply Briefs, the decision of the Examiner rejecting
claims 16-24 and 73-83 under 35 U.S.C. § 103(a) as unpatentable over the
combination of Cai '537, Cai '441, and Lau alone, or further in view of
Bhullar is reversed.
REVERSED
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