Ex Parte Crook et al

Patent Trial and Appeal Board

May 16, 2016

11628443 (P.T.A.B. May. 16, 2016)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE
111628,443 0512512007
105032 7590 05/17/2016
Krista P, Kauppinen/E Stewart Mittler
BioTime, Inc.
1010 Atlantic A venue, Suite 102
Alameda, CA 94501
FIRST NAMED INVENTOR
Jeremy M Crook
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.
BIOT-051 5084
EXAMINER
LANKFORD JR, LEON B
ART UNIT PAPER NUMBER
1651
MAILDATE DELIVERY MODE
05/1712016 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 JEREMY M. CROOK and LUCY KRAVETS 1
Appeal2013-010626
Application 11/628,443
Technology Center 1600
Before ERIC B. GRIMES, JEFFREY N. FREDMAN, and
RICHARD J. SMITH, Administrative Patent Judges.
GRIMES, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal under 35 U.S.C. § 134(a) involving claims to a
method of freezing human embryonic stem cells, which have been rejected
as obvious. We have jurisdiction under 35 U.S.C. § 6(b).
We reverse.
STATEMENT OF THE CASE
Cryopreserving cells is useful for long-term storage but the freezing
process can result in damage to the cells. (Spec. 1 :9-17 .) "At high cooling
rates ... intracellular ice formation is observed which is lethal to the cell,"
while "[a]t low cooling rates, cells are exposed for long periods of time at
1 Appellants identify the Real Party in Interest as ES Cell International Pte
Ltd. (Appeal Br. 3.)
Appeal2013-010626
Application 11/628,443
high subzero temperatures to high extracellular concentrations resulting in
potentially damaging high intracellular concentrations." (Id. at 1 :25-32.)
The Specification describes "a method for freezing a stem cell ... ,
the method including the steps of providing a cell suspension, performing
ice nucleation on the cell suspension, and decreasing the temperature of the
ice nucleated cell suspension to a temperature sufficiently low to allow long
term storage of the stem cell." (Id. at 6:4--8.)
Claims 1 and 4--3 8 are on appeal. Claim 1 is the only independent
claim and reads as follows (emphasis added):
1. A method for freezing a pluripotent stem cell, the method including
the steps of providing a pluripotent stem cell suspension, performing ice
nucleation on the pluripotent stem cell suspension by rapidly lowering the
temperature of the suspension to a nucleating point at a rate from
about -5°C/minute to about -55°C/minute to provide an ice nucleated
pluripotent stem cell suspension, and lowering the temperature of the ice
nucleated pluripotent stem cell suspension to a temperature sufficiently low
to allo\'l/ long term storage of the pluripotent stem cell, \'I/herein upon
thawing, the pluripotent stem cell retains pluripotency, and wherein the
pluripotent stem cell is a human embryonic stem cell.
Appeal Br. 22 (Claims Appendix).
DISCUSSION
The Examiner has rejected all of the claims on appeal under 35 U.S.C.
§ 103(a) as obvious based on Acton2 and Acker. 3 (Ans. 4.) The Examiner
finds that both Acton and Acker "teach that cells can be cryopreserved by
2 GB 2 330 516 A, published Apr. 28, 1999 ("Acton").
3 WO 2004/010780 A2, published Feb. 5, 2004 ("Acker").
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Application 11/628,443
precooling a suspension of the cells to induce ice nucleation and then lower
the temperature further for ultimate storage." (Id.)
The Examiner finds that, although neither reference teaches cryo-
preserving stem cells, "it would be have been obvious to apply known
cellular cryopreservation techniques to human embryonic stem cells"
because the same techniques had been applied to other cells. (Id. at 4--5.)
The Examiner also concludes that the rate of cooling required by the claims
would have been obvious, because optimizing the parameters of a known
process is obvious to those skilled in the art. (Id. at 5---6.)
Appellants argue, among other things, that
the claim recites "rapidly lowering the temperature of the
suspension to a nucleating point at a rate from about -5°C/minute
to about -55°C/minute to provide an ice nucleated pluripotent
stem cell suspension." While cooling rates, generally, are
described in the cited references to be result effective variables,
the Examiner has pointed to nothing in the record that establishes
the rate of nucleation was a recognized result effective variable
before the instant application was filed.
(Appeal Br. 16.)
Appellants argue that, because the record does not show that the
nucleation rate was a result-effective variable (id. at 17), the rule relied on
by the Examiner does not apply (id. at 16).
We agree with Appellants that the evidence does not support the
Examiner's conclusion that the teachings of Acton and Acker would have
led a skilled artisan to optimize the rate of cooling cells to the nucleation
temperature. Acton discloses a process of cryopreserving cells (Acton 1)
that includes cooling to a "holding" temperature (Thold) and holding them at
T hold while nucleating, then reducing the temperature from T hold to the
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Application 11/628,443
storage temperature (Tsolidification) (id. at 2-3). Acton teaches that, following
ice nucleation, the cells are conventionally cooled with a linear reduction in
temperature (id. at 2), while in Acton's process the reduction in temperature
from Thold to Tsolidification "should take place in a non-linear manner" (id. at 3).
Acker discloses a method for cryopreserving cells that includes
"cooling the cells to the predetermined nucleation temperature, nucleating
intracellular ice formation, and cooling the cells to a temperature lower than
the predetermined nucleation temperature." (Acker 2: 15-20.) Acker states
that "the cell type or cell line to be cryopreserved is cooled at any rate to the
predetermined nucleation temperature, and intracellular ice formation is
induced." (Id. at 5:26-28.) Acker states that "[a]fter nucleation of
intracellular ice formation, the cell type or cell line to be cryopreserved can
be cooled to a predetermined storage temperature .... The rate of cooling
can be from about 1°C/min to about 500°C/min (i.e., slow or rapid
cooling)." (Id. at 6:30 to 7:4.)
Thus, both Acton and Acker disclose that particular rates of
temperature reduction after nucleation but the Examiner has not pointed to
any discussion of optimizing the rate of temperature reduction to the
nucleation temperature in either reference. The Examiner did not respond to
Appellants' argument on this point. (See Ans. 6-7.)
In summary, we conclude that the Examiner has not provided
sufficient evidence or technical reasoning to show that it would have been
obvious to a person of ordinary skill in the art to optimize the rate of
temperature reduction to the nucleation temperature in a process of cryo-
preserving cells. Therefore, the Examiner has not shown that the method of
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Application 11/628,443
the claims on appeal would have been obvious based on Acton and Acker.
See In re Antonie, 559 F.2d 618, 620 (CCPA 1977) (While "the discovery of
an optimum value of a variable in a known process is normally obvious,"
one exception to that rule is where "the parameter optimized was not
recognized to be a result-effective variable.").
SUMMARY
We reverse the rejection of claims 1 and 4--38 under 35 U.S.C.
§ 103(a) as obvious based on Acton and Acker.
REVERSED
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