12546231 (P.T.A.B. May. 19, 2016)

Ex Parte Pathak et al

Patent Trial and Appeal BoardMay 19, 2016

12546231 (P.T.A.B. May. 19, 2016)

UNITED STA TES p A TENT AND TRADEMARK OFFICE APPLICATION NO. FILING DATE FIRST NAMED INVENTOR 12/546,231 08/24/2009 Chandrashekhar P. Pathak 62274 7590 05/20/2016 DARDI & HERBERT, PLLC Moore Lake Plaza, Suite 205 1250 East Moore Lake Drive Fridley, MN 55432 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. 3516.18US03 3019 EXAMINER SKOWRONEK, KARLHEINZ R ART UNIT PAPER NUMBER 1676 MAILDATE DELIVERY MODE 05/20/2016 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 CHANDRASHEKHAR P. PATHAK, AMARPREET S. SAWHNEY, and JAMES H. DREHER1 Appeal2014-000426 Application 12/546,231 Technology Center 1600 Before FRANCISCO C. PRATS, ULRIKE W. JENKS, and TIMOTHY G. MAJORS, Administrative Patent Judges. MAJORS, Administrative Patent Judge. DECISION ON APPEAL This is an appeal under 35 U.S.C. Â§ 134 involving claims to methods of forming crosslinked gels on live tissue, which have been rejected as anticipated and obvious. We have jurisdiction under 35 U.S.C. Â§ 6(b). We reverse. STATEMENT OF THE CASE "[C]rosslinkers are generally useful to form crosslinked materials, e.g., surgical adhesives, glues, dressings, hemostatic agents, wound healing 1 Appellants identify the Real Party in Interest as Incept, LLC. (Appeal Br. 3.) Appeal2014-000426 Application 12/546,231 agents, depots for drug delivery, or sealants by using the crosslinkers to react with natural or synthetic precursors." (Spec. 31, 11. 3-5.) The Specification discloses methods for "forming a biomaterial in situ comprising combining a precursor with a solution of a crosslinker in an organic solvent to covalently crosslink the precursor to form a crosslinked gel." (Id. at 5, 11. 1-3.) "[I]n situ formation of a material ... refers to forming a material at its intended site of use." (Id. at 32, 11. 11-12.) Claims 1, 2, 8, and 10-19 are on appeal. 2 Claim 1 is illustrative: 1. A method for forming a biomaterial in situ comprising: combining a nonaqueous solution of a crosslinker in a water soluble organic solvent with a water soluble precursor to covalently crosslink the precursor to form a crosslinked gel on a live tissue of a patient at the site wherein the gel is to be used, with the crosslinker comprising a plurality of first functional groups and the precursor comprising a plurality of second functional groups, with the first functional groups chemically reacting with the second functional groups in situ to form covalent bonds and thereby form the crosslinked gel. 2 In response to a species election requirement, Appellants elected: (1) "4 arm-n-hydroxysuccinimide ester of polyethyelene glycol carboxymethylene- butyric acid, average molecular weight 10000 Daltons (Shearwater 4 arm CM-HBA-NS-lOK)" as the crosslinker and "n-hydroxysuccinimide" as the first functional groups; (2) "trilysine" as the precursor and "primary amines" as the second functional groups; and (3) "PEG 400" as the solvent. (See Resp. to Restriction Requirement dated 3/6/2012; see also, Final Act. 3.) We, therefore, limit our analysis of claims to the patentability of the elected species, and the extent to which the claims read on them. See Ex parte Ohsaka, 2 USPQ2d 1460, 1461(BPAI1987). 2 Appeal2014-000426 Application 12/546,231 The claims stand rejected as follows: Claims 1, 2, 8, 14, 15, 18, and 19 as anticipated under 35 U.S.C. Â§ 102(b) based on Sawhney et al., (U.S. Patent 6,703,047 B2, issued Mar. 9, 2004) ("Sawhney"). 3 Claims 1, 2, 8, and 10-17 as obvious under 35 U.S.C. Â§ 103(a) over Pathak et al., (U.S. 2004/0023842 Al, published Feb. 5, 2004) ("Pathak '842") and Pathak (U.S. 2002/0114775 Al, published Aug. 22, 2002) ("Pathak '775"). DISCUSSION Anticipation The Examiner rejected claims 1, 2, 8, 14, 15, 18, and 19 as anticipated by Sawhney. The Examiner finds Sawhney (identified as "Sawhney and Edelman" by the Examiner) teaches, as in claim 1, to mix N-hydroxysuccinimide (NHS) polyethylene glycol (PEG )/the crosslinker (Detailed Description ( 1)-(6)) and precursor having amines (Example 1) in the presence of an anhydrous organic solvent (Example 6). Sawhney and Edelman teach combining the crosslinker and precursor has formed the covalently crosslinked gel (Example 6). Therefore, Sawhney and Edelman teach a method combining a crosslinker in an 3 In the Final Action dated 9/28/2012, the Examiner also identifies claim 13 as rejected underÂ§ 102(b). Claim 13 depends from claim 12, which depends from claim 11. Because neither claim 11 or 12 are included in the Â§ 102(b) rejection, claim 13 appears to be included by error. (See Ans. 5 (removing claim 13 from theÂ§ 102(b) rejection).) We thus reverse theÂ§ 102(b) rejection as to claim 13. 3 Appeal2014-000426 Application 12/546,231 organic solvent with a precursor to form the in suit [sic] covalent bonds crosslinker gel. (Final Act. 3; see also, Ans. 5.) Appellants argue Sawhney does not disclose all the elements of claim 1. According to Appellants, Example 6 of Sawhney discloses the use of an "organic solvent in an intermediate step and not in vivo." (Appeal Br. 8.) Appellants contend "the organic solvent [of Sawhney] is gone by the time the dried particles are used in vivo." (Id.) Thus, Appellants argue, Sawhney cannot anticipate claim 1, which requires a "process to form the gel [that] involves a solution of a crosslinker in an organic solvent combined with a water soluble precursor" to "form a gel on a live tissue of a patient at the site where the gel is to be used." (Appeal Br. 8-9; see also, Reply Br. 3.)4 In order to anticipate, all the claim elements and their limitations must be shown, expressly or inherently, in a single prior art reference. Net MoneyIN, Inc. v. VeriSign, Inc., 545 F.3d 1359, 1371 (Fed. Cir. 2008). ("[U]nless a [prior art] reference discloses within the four comers of the document not only all of the limitations claimed but also all of the limitations arranged or combined in the same way as recited in the claim, it cannot be said to prove prior invention of the thing claimed and, thus, cannot anticipate under 35 U.S.C. Â§ 102.") 4 Appellants argue the "conventional wisdom was that live tissues should not be exposed to an organic solvent." (Appeal Br. 7-8.) This argument is, however, irrelevant to whether Sawhney anticipates the claims underÂ§ 102. 4 Appeal2014-000426 Application 12/546,231 We agree with Appellants that Sawhney does not disclose the method of claim 1. Among other things, the "anhydrous organic solvent" of Sawhney is mixed with dry "'insoluble' 'particulate' hydrogel" that is then dried again and the solvent is removed before any application to live tissue. (Appeal Br. 8-9; Sawhney col. 5, 1. 65 through col. 6, 1. 27.) Claim 1, on the other hand, is a method of "combining a nonaqueous solution of a crosslinker in a water soluble organic solvent with a water soluble precursor ... to form a crosslinked gel on a live tissue of a patient at the site wherein the gel is to be used." (Appeal Br. 15 (claim 1).) In other words, as claimed, the solution of cross linkers in an organic solvent is applied to live tissue and forms a gel in situ. This differs from Sawhney, which teaches using dry/dehydrated constituents that are "activated solely by the presence of aqueous physiological surroundings" - thus addressing the "[ s ]ignificant limitations [that] exist when using solutions for in situ therapy." (Sawhney col. 1, 11. 26-32, col. 2, 11. 24--55; see also, id. at Abstract ("The dehydrated precursors are premixed prior to in situ therapy and utilize naturally- occurring body fluids as an aqueous environment that initiates transformation").) The Examiner responds to Appellants' argument by stating that the "hydrogel mixture of Sawhney et al. that contains PEG precursor, PEG crosslinker, and PEG solvent is a PEG mixture which is a nonaqueous solution used in vivo." (Ans. 10.) This counterargument is, however, unclear and unpersuasive. The Examiner has not shown where and how Sawhney discloses a method of combining a nonaqueous solution of a crosslinker in a water soluble organic solvent with a precursor to form a 5 Appeal2014-000426 Application 12/546,231 crosslinked gel in situ. Thus, based on the record before us, we conclude that the Examiner has not established by a preponderance of the evidence that Sawhney anticipates claim 1. For the reasons above, we reverse the Â§ 102(b) rejection of claim 1. Claims 2, 8, 14, 15, 18, and 19 all depend (directly or indirectly) from claim 1, so we reverse the Â§ 102(b) rejection as to those claims as well. Obviousness The Examiner contends that claims 1, 2, 8, and 10-17 would have been obvious over Pathak '842 and Pathak '775. According to the Examiner, Pathak '842 Teach[ es] a method for forming in situ hydrogels (Summary of Invention). Pathak et al (842 Al) teach to mix 4 arm CM- HBA-NS (MW 10,000 Da)/ the crosslinker (Examples, 16, 19 and 20) and Tri-lysine/the precursor (Example 12) in the presence of a solvent buffer (Examples, 12, 16, 19, and 20). (Final Act. 5; see also, Ans. 7.) The Examiner finds that Pathak '842 does not teach the use of a "water soluble organic solvent" as claimed. (Final Act. 5 ("The difference between the prior art and the claimed invention is that Pathak et al. (842 Al) do not teach the solvent is PEG 400.").) So the Examiner turns to Pathak '775, which the Examiner contends teaches "that the water soluble organic solvent, such as PEG 400 can provide better control [of] the nature of the protein/precursor when forming the hydro gel ([0032])." (Final Act. 5.) The Examiner concludes that it would have been obvious to "present the crosslinker and precursor of Pathak et al. (842 Al) in the PEG 400 solvent of Pathak (775 Al)." (Id. at 5---6.) 6 Appeal2014-000426 Application 12/546,231 Appellants argue, inter alia, that the references "do not teach the claimed 'nonaqueous solution of a cross linker in a water soluble organic solvent' as used in the context of the claim." (Appeal Br. 11.) More specifically, Appellants contend that, as claimed, the "organic solvent is solvating the crosslinker. The crosslinker is in solution in the solvent. The solution is nonaqueous, so water is not solvating the crosslinker to dissolve the crosslinker to form a solution." (Id.) Because, Appellants argue, the Pathak references "do not disclose these features and, further, disclose using water (aqueous) in the relevant solutions ... [where] the claimed method's crosslinker is 'nonaqueous,' i.e., it is free of water," the Examiner erred in finding the claims obvious. (Id.) Appellants' argument is persuasive. The claims require a "nonaqueous solution of a crosslinker in a water soluble organic solvent."5 Although the Examiner has pointed to a disclosure in Pathak '775 regarding the addition of PEG 400, which the Examiner contends is an organic solvent, the Examiner has not explained sufficiently where Pathak '842 or Pathak '775 disclose a method of forming a crosslinked gel in situ without an 5 The Specification describes the desirability of gel-forming methods where organic solvents are used in lieu of solutions having water: "non- conventional solvents may also be used, specifically non-aqueous water soluble biocompatible, non-reactive solvents .... The reduction or elimination of water can improve storage life and stability of crosslinker or other precursors. Further eliminating water can advantageously eliminate a step of dissolving a crosslinker or other precursor in water. For instance, crosslinkers may be dissolved in nonaqueous solvents and be liquids that are ready for use as-is, and without the addition of solvents or reaction aids." (Spec. 16, 11. 10-21.) 7 Appeal2014-000426 Application 12/546,231 aqueous solution. For example, the Examiner has cited no disclosure of using an organic solvent instead of an aqueous solution for forming a cross- linked gel in situ, or provided any reasoning for why a person of ordinary skill in the art would make such a change. "[T]here must be some articulated reasoning with some rational underpinning to support the legal conclusion of obviousness." KSR Int'! Co. v. Teleflex Inc., 550 U.S. 398, 418 (2007) (quoting In re Kahn, 441F.3d977, 988 (Fed. Cir. 2006)). The Examiner responds to Appellants' argument on this point, contending that the "mixture of PEG precursor and crosslinker in PEG solution is a 'nonaqueous solution."' (Ans. 11.) But this leaves unaddressed - and thus undisputed-Appellants' assertion that Pathak '842 and Pathak '775 "disclose using water (aqueous) in the relevant solutions." (Appeal Br. 11.) If the Examiner is contending, for example, that it would have been obvious to modify the teachings in Pathak '842 so that a hydro gel is formed on a live tissue with an organic solvent, and without an aqueous solution to solvate the crosslinker, the Examiner has not made that position clear or provided the necessary support as part of the existing rejection. Appellants and the Examiner also argue whether the PEG 400 disclosed in Pathak '775 is, in fact, an organic solvent used during a process of making the hydro gel on live tissue in the manner claimed. (Appeal Br. 13; Ans. 11.) Pathak '775 discloses "[o]ther means of tailoring the hyrdogels [sic] to further control the nature of the protein concentrate produced by the subject method include using hydrogels comprising agents that act as water absorbents and/or precipitants, where such agents include ethanol, PEG 400, phosphate buffer and the like." (Pathak '775 i-f 32.) 8 Appeal2014-000426 Application 12/546,231 Based on the record before us, it has not been established that the PEG 400 disclosed in Pathak '775 functions as an organic solvent (solvating a crosslinker in solution) when forming a gel on live tissue. For the reasons above, we conclude that the Examiner has not established that claim 1 would have been obvious to a person of skill in the art at the time of the invention over Pathak '842 and Pathak '775. We thus reverse the rejection of claim 1 under 35 U.S.C. Â§ 103(a) over Pathak '842 and Pathak '775. Similarly, we reverse the rejections underÂ§ 103(a) of claims 2, 8, and 10-17, which depend directly or indirectly from claim 1. SUMMARY We reverse the rejections of claims 1, 2, 8, 14, 15, 18, and 19 as anticipated under 35 U.S.C. Â§ 102(b) by Sawhney. We further reverse the rejections of claims 1, 2, 8, and 10-17 as obvious under 35 U.S.C. Â§ 103(a) over Pathak '842 and Pathak '775. REVERSED 9