Ex Parte Crook et al

Patent Trial and Appeal BoardMay 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. Â§ 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. Â§ 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 -5Â°C/minute to about -55Â°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. Â§ 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"). 2 Appeal2013-010626 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 -5Â°C/minute to about -55Â°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 3 Appeal2013-010626 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 1Â°C/min to about 500Â°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 4 Appeal2013-010626 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. Â§ 103(a) as obvious based on Acton and Acker. REVERSED 5