Covidien LP

Patent Trials and Appeals BoardJan 1, 2021

2020002588 (P.T.A.B. Jan. 1, 2021)

UNITED STATES PATENT AND TRADEMARK OFFICE 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 APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO. 15/700,446 09/11/2017 Valentino J. TRAMONTANO H- KN-03032.USV8/1214-111 7579 143331 7590 01/01/2021 Medtronic, Inc./RCS Shumaker 60 Middletown Avenue Mailstop 54, Legal Dept. North Haven, CT 06473 EXAMINER PHAN, DOAN THI-THUC ART UNIT PAPER NUMBER 1613 NOTIFICATION DATE DELIVERY MODE 01/01/2021 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): medtronic@ssiplaw.com rs.patents.two@medtronic.com PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE ____________ BEFORE THE PATENT TRIAL AND APPEAL BOARD ____________ Ex parte VALENTINO J. TRAMONTANO, BRENT MARSDEN, ROBERT F. ALMEIDA, ERIC W. DAHL, JAMES W. RAWLINS, and SHARATHKUMAR K. MENDON ____________ Appeal 2020-002588 Application 15/700,446 Technology Center 1600 ____________ Before DONALD E. ADAMS, RICHARD M. LEBOVITZ, and JOHN G. NEW, Administrative Patent Judges. ADAMS, Administrative Patent Judge. DECISION ON APPEAL Pursuant to 35 U.S.C. § 134(a), Appellant1 appeals from Examiner’s decision to reject claims 1–9 and 13–23 (Final Act.2 2). We have jurisdiction under 35 U.S.C. § 6(b). We AFFIRM. 1 We use the word “Appellant” to refer to “applicant” as defined in 37 C.F.R. § 1.42. Appellant identifies the real party in interest as “Medtronic plc of Dublin, Ireland, which is the ultimate parent entity of the assignee of record, Covidien LP” (Appellant’s September 11, 2019 Appeal Brief (Appeal Br.) 3). 2 Examiner’s April 11, 2019 Final Office Action. Appeal 2020-002588 Application 15/700,446 2 STATEMENT OF THE CASE Appellant’s disclosure “relates to antimicrobial formulations and coatings for medical devices and in particular implantable medical devices” (Spec. ¶ 2). Claims 1, 4, 17, 18, and 23 are reproduced below: 1. A medical device comprising an antimicrobial coating, wherein the coating comprises at least one water permeable polymer and uniformly dispersed particles therein of at least one antimicrobial agent, wherein the at least one antimicrobial agent comprises a silver-based salt and a polybiguanide salt, wherein the silver-based salt is silver sulfadiazine and the polybiguanide salt is chlorhexidine diacetate, wherein the coating comprises from about 2 weight percent (wt.%) to about 10 wt.% of silver sulfadiazine, wherein the coating comprises at least 9 wt. % of chlorhexidine diacetate, wherein the coating comprises from about 70 wt. % to about 90 wt. % of the water permeable polymer, and wherein the particles and any agglomerations of the antimicrobial agent have an average size of about 5 microns to about 50 microns. (Appeal Br. 18.) 4. The medical device of claim 1, wherein the at least one water permeable polymer encapsulates the at least one antimicrobial. (Id.) 17. The medical device of claim 1, wherein the coating has a thickness of between about 20 microns to about 80 microns. (Id. at 20.) Appeal 2020-002588 Application 15/700,446 3 18. An antimicrobial formulation for coating a medical device prepared according to a process comprising: milling at least one water permeable polymer which is dissolved in a liquid medium with at least one antimicrobial agent which is insoluble in the liquid medium to form the antimicrobial formulation in which the at least one water permeable polymer encapsulates the at least one antimicrobial agent; and adding a primary C1-6 alcohol to the antimicrobial formulation, wherein the at least one antimicrobial agent includes a silver-based antimicrobial agent, and wherein the at least one water permeable polymer includes at least one of a polyurethane or a thermoplastic polyurethane elastomer, wherein the particles and any agglomerations of the antimicrobial agent have an average size of about 5 microns to about 50 microns. (Id.) 23. The medical device of claim 1, wherein the at least one water permeable polymer encapsulates the particles of the at least one antimicrobial agent to prevent re-agglomeration of the particles. (Id. at 21.) Grounds of rejection before this Panel for review: Claims 1–9, 13–17, and 21–23 stand rejected under 35 U.S.C. § 103(a) as unpatentable over the combination of Fox,3 Lin,4 and Gratz.5 Claims 18–20 stand rejected under 35 U.S.C. § 103(a) as unpatentable over the combination of Fox and Lin. 3 Fox, Jr. et al., US 5,019,096, issued May 28, 1991. 4 Lin et al., US 2014/0228466 A1, published Aug. 14, 2014. 5 Gratz et al., US 2011/0244016 A1, published Oct. 6, 2011. Appeal 2020-002588 Application 15/700,446 4 ISSUE Does the preponderance of evidence relied upon by Examiner support a conclusion of obviousness? FACTUAL FINDINGS (FF) FF 1. Fox discloses: A method of preparing an infection-resistant medical device comprising one or more matrix-forming polymers selected from the group consisting of biomedical polyurethane, biomedical silicones and biodegradable polymers, and antimicrobial agents, especially a synergistic combination of a silver salt and chlorhexidine (or its salts). (Fox, Abstr. (emphasis added); see Ans. 4, 13.) FF 2. Fox discloses that “the combination of chlorhexidine and sulfadiazine is known in topical applications to exhibit synergism against strains of Pseudomonas, Proteus, and Staphylococcus” (Fox 1:56–59; see also id. at 32:20 (Table XVIII ((Fox discloses that the combination of silver sulfadiazine (1%) and chlorhexidine (1%) inhibits Candida albicans)). FF 3. Fox discloses: A method for coating a medical device to provide an infection- resistant coating thereon which comprises the steps of: (a) dissolving a matrix-forming polymer in a solvent therefore; (b) dissolving an antimicrobial agent selected from the group consisting of chlorhexidine and its salts in a solvent which is miscible with the solvent polymer mixture prepared in step (a); (c) dispersing a silver salt in one of the solutions prepared in (a) or (b); (d) combining the solvent solutions and dispersions prepared in steps (a), (b) and (c) to provide a coating vehicle; (e) applying the coating vehicle to the surface of the medical device; and Appeal 2020-002588 Application 15/700,446 5 (f) drying the coated medical device. (Fox 2:47–65; see also id. at 12:55–13:33 (describing solvents, including alcohols, such as ethanol); see generally Ans. 4, 13.) FF 4. Fox discloses that chlorhexidine diacetate and silver sulfadiazine are useful antimicrobial agents in its medical device coating (see Fox 13:36–44; see also id. at 24:30–41 (Fox disclosing the use of chlorhexidine diacetate to coat a medical device)). FF 5. Fox discloses the use of silver sulfadiazine “having a particle size of 5μ or less” or “depending on the contemplated use of the medical device,” “silver sulfadiazine having a larger average particle size” (Fox 15:46–52; see Ans. 4, 13). FF 6. Fox discloses that the antimicrobial agent may be placed in a solution containing polyurethane and a carrier and, thereafter, applied to a medical device by spraying or dipping the device in the antimicrobial solution (see Fox 29:29–33; see also Ans. 8, 22). FF 7. Fox discloses that “[t]he antimicrobial agent is preferably employed in the coating vehicle at a level such that the final coating contains from 10 to 70% by weight of the antimicrobial agent,” which “may be accomplished by providing a concentration of, for example, 0.5 to 3% . . . chlorhexidine acetate and 0.5 to 5% . . . silver sulfadiazine in the coating vehicle” (Fox 14:1–7; see 15:37–43 (Fox discloses that “[c]oncentrations of the coating vehicle, the antimicrobial composition, the coating composition and resultant coating can be selected as desired,” wherein “good results have been obtained when [the combination of chlorhexidine acetate and silver sulfadiazine] are present in a proportion ranging from 1:9 to 9:1, respectively” and “[f]urther, it is preferred that this combination of Appeal 2020-002588 Application 15/700,446 6 antimicrobial agents be present at levels of from 10 to 70% by weight of the final coating”); see also Ans. 4). FF 8. Examiner finds that Lin discloses “an antimicrobial coating comprising a water permeable polymer and insoluble antimicrobial agents including chlorhexidine diacetate and silver sulfadiazine, wherein the insoluble antimicrobial agents hav[e] a particle size of 15 or less” (Ans. 5 (citing Lin ¶¶ 15, 16, 21, 23, 37–40, 43–47, Abstr., and claims 1–4, 9, and 13)). FF 9. Examiner finds that the combination of Fox and Lin does not disclose “the amount of the water permeable polymer (polyurethane) in the coating” (Ans. 6). FF 10. Gratz discloses “a medical implant whose surface is completely or partially covered by a coating composed of at least one active substance or containing at least one active substance,” such as an antimicrobial (Gratz ¶¶ 2, 8, 70; see also id. at Abstr.; Ans. 6). FF 11. Gratz discloses that “the surface of the [medical] implant is at least partially covered by a coating containing one or more active substances, wherein at least one of the active substances is a nitrostatin” (Gratz ¶ 12). FF 12. Gratz discloses that the antimicrobial, i.e. at least one nitrostatin, “may be embedded in a polymer carrier matrix,” such as “polyurethanes” (Gratz ¶¶ 34–35; see Ans. 6). FF 13. Gratz discloses that “[t]he coating may contain a polymer which is able to form a carrier matrix,” wherein “[t]he proportion by weight of such a polymer matrix in the components forming the coating may be at least 40%, further at least 70%, or other percentages including less th[a]n 40%” and “[t]he proportion by weight of the [antimicrobials, including] at least one Appeal 2020-002588 Application 15/700,446 7 nitrostatin in the components forming the coating may be less than 60%, further less than 30%, and may be in a range of 10% to 25%” (Gratz ¶ 30; see Ans. 6). FF 14. Gratz discloses that “[t]he layer thickness may be in the range of 1 nm to 100 μm, further 300 nm to 15 μm, and still further 5 μm to 60 μm, or other thicknesses, including less than 1 nm or greater th[a]n 100 μm,” wherein “[t]hickness[es] in the 5 μm to 60 μm range are believed to provide superior results in at least many applications” (Gratz ¶ 30; see Ans. 11). ANALYSIS The rejection over Fox, Lin, and Gratz: Based on the combination of Fox, Lin, and Gratz, Examiner concludes that, at the time Appellant’s invention was made, it would have been prima facie obvious to optimize the amounts of the antimicrobial and polymer components of a coating for a medical device, and further optimize the average particle size of the antimicrobials to about 5 microns or greater (see Ans. 5–7; see also FF 1–14). We find no error in Examiner’s prima facie case of obviousness. Claim 1: The medical device of Appellant’s claim 1 comprises an antimicrobial coating that comprises at least one water permeable polymer and uniformly dispersed particles of silver sulfadiazine and chlorhexidine diacetate, wherein the coating comprises from about 2 weight percent (wt.%) to about 10 wt.% of silver sulfadiazine, wherein the coating comprises at least 9 wt. % of chlorhexidine diacetate, Appeal 2020-002588 Application 15/700,446 8 wherein the coating comprises from about 70 wt. % to about 90 wt. % of the water permeable polymer, and wherein the particles and any agglomerations of the antimicrobial agent have an average size of about 5 microns to about 50 microns. (Appeal Br. 18.) On this record, Fox discloses medical device coatings comprising polyurethane polymer in combination with antimicrobial combinations such as the recognized synergistic combination of silver sulfadiazine and chlorhexidine (see FF 1–7). Gratz discloses a medical device, i.e., implant, “whose surface is completely or partially covered by a coating composed of at least one active substance or containing at least one active substance,” such as an antimicrobial (FF 10). Gratz’s medical device may contain a polymer, such as polyurethane, which is able to form a carrier matrix, wherein the proportion by weight of such a polymer matrix in the components forming the coating may be at least 70% (FF 12–13). At least 70% encompasses the range of about 70–90 wt. % set forth in Appellant’s claim 1. “[W]here there is a range disclosed in the prior art, and the claimed invention falls within that range, there is a presumption of obviousness.” Iron Grip Barbell Co. v. USA Sports, Inc., 392 F.3d 1317, 1322 (Fed. Cir. 2004). Thus, we find no error in Examiner’s conclusion that it would have been prima facie obvious to coat a medical device with a coating that comprises at least 70% polyurethane in combination with an antimicrobial composition that includes silver sulfadiazine and chlorhexidine (see FF 1–7, 10–14). Appeal 2020-002588 Application 15/700,446 9 For the foregoing reasons, we are not persuaded by Appellant’s contention that because Gratz discloses the use of one or more antimicrobials, wherein at least one of the antimicrobials is a nitrostatin and Fox does not expressly disclose the use of a nitrostatin antimicrobial, a person of ordinary skill in this art would not appreciate that a coating for Fox’s medical device may be formulated with at least 70% polyurethane, as disclosed by Gratz (see Appeal Br. 7 (Appellant contends “[b]ecause the compositions described by Fox does not also include nitrostatin, modifying the amount of polymeric coating agent in the composition of Fox to be in the range recited by [Appellant’s] independent claim 1 cannot be characterized as mere routine experimentation”); see also Reply Br. 3–4; cf. FF 1–7, 10– 14). Simply stated, Fox and Gratz both disclose medical device coatings comprising polyurethane and antibiotics (see, e.g., FF 6, 11–12). In combination, Fox and Gratz suggest that the composition comprises at least 70% polyurethane (see, e.g., 1–7, 10–14). Appellant failed to establish an evidentiary basis on this record to support a conclusion that a person of ordinary skill in this art would have reasonable understood that the choice of antibiotic, e.g., silver sulfadiazine and chlorhexidine, with or without nitrostatin, for use in the coating would have resulted in a change in the percentage of polyurethane present in the coating. Fox discloses the use of an antimicrobial agent, i.e., silver sulfadiazine, “having a particle size of 5μ[m] or less” or a larger average particle size “depending on the contemplated use of the medical device” (FF 5). A 5 μm or larger average particle size encompasses an average particle size of about 5 microns to about 50 microns, as set forth in Appellant’s claimed invention. See Iron Grip Barbell Co., 392 F.3d at 1322 (“[W]here Appeal 2020-002588 Application 15/700,446 10 there is a range disclosed in the prior art, and the claimed invention falls within that range, there is a presumption of obviousness.”). Therefore, we are not persuaded by Appellant’s contentions regarding particle size (see Appeal Br. 7–9, 10–11; see also Reply Br. 4–6).6 Appellant contends that its “disclosure outlines unexpected results,” wherein “the antimicrobial release rates of the commercially available ARROWgard BlueTM hemodialysis catheter [is compared to] a catheter coated with an example antimicrobial formulation in accordance with [Appellant’s independent claim 1]” (Appeal Br. 9 (citing Appellant’s Figures 1–2); see also id. at 9–10). Appellant further contends that its “disclosure displays that the example coating formulation in accordance with [its] claim 1 had superior antimicrobial activity across all 3 microorganisms as compared to the commercially available catheter” (id. at 10 (citing Appellant’s Figure 3). We are not persuaded. As Examiner explains, the coating encompassed by Appellant’s claim 1 is much broader than the coating used in Appellant’s Figures 1–3 and, thus, Appellant’s evidence of unexpected results is not commensurate in scope with Appellant’s claimed invention (Ans. 21). See In re Lindner, 457 F.2d 506, 508 (CCPA 1972) (“It is well established that the objective evidence of nonobviousness must be commensurate in scope with the claims.”). In addition, Examiner explains that Appellant’s evidence of unexpected results fails to compare the claimed invention against the closest 6 Because the combination of Fox and Gratz makes obvious Appellant’s claimed invention, we do not rely on Lin. The Board may rely upon less than all the references cited by the Examiner. See In re May, 574 F.2d 1082, 1090 (CCPA 1978); In re Kronig, 539 F.2d 1300, 1304 (CCPA 1976). Appeal 2020-002588 Application 15/700,446 11 prior art on this record, Fox (Ans. 21). See In re Baxter-Travenol Labs., 952 F.2d 388, 392 (Fed. Cir. 1991) (“[W]hen unexpected results are used as evidence of nonobviousness, the results must be shown to be unexpected compared with the closest prior art.”). Appeal 2020-002588 Application 15/700,446 12 Claim 4: The medical device of Appellant’s claim 4 depends from and further limits claim 1 to require that the at least one water permeable polymer encapsulates the at least one antimicrobial (see Appeal Br. 18). Fox discloses that the antimicrobial agent may be placed in a solution containing polyurethane and a carrier and, thereafter, applied to a medical device by spraying or dipping the device in the antimicrobial solution (FF 6). As Examiner explains: [T]he term “encapsulates” as recited in dependent claim 4 is not defined in the specification. Thus, the plain meaning of the term “encapsulates” using broadest reasonable interpretation (BRI) as it pertain to claim 4 would be interpreted as the water permeable polymer surrounds the antimicrobial agent or the antimicrobial is enclosed in the water permeable polymer. . . . [Fox] describes the antimicrobial agents are placed in a solution containing polyurethane (water permeable polymer of the claimed invention), thereby the antimicrobial agents are dispersed/suspended within the polyurethane solution or in other words, the polyurethane surround the antimicrobial agents or the antimicrobial agents in enclosed in the polyurethane solution. . . . . As such, it is reasonably obvious that the water permeable polymer (polyurethane) of [F]ox “encapsulates” the antimicrobial agent because . . . [Fox’s] polyurethane is a polymer matrix to which the antimicrobial agents is incorporated or retained therein, thereby the antimicrobial agents are surrounded or encapsulated by the matrix. (Ans. 22–23.) We find no error in Examiner’s rationale and, therefore, are not persuaded by Appellant’s contentions to the contrary (Appeal Br. 11– 13). Appeal 2020-002588 Application 15/700,446 13 Claim 17: The medical device of Appellant’s claim 7 depends from and further limits claim 1 to require that the coating has a thickness of between about 20 microns to about 80 microns (see Appeal Br. 20). Gratz discloses a medical device with a coating layer thickness “in the range of 1 nm to 100 μm, further 300 nm to 15 μm, and still further 5 μm to 60 μm, or other thicknesses, including less than 1 nm or greater th[a]n 100 μm,” wherein “[t]hickness[es] in the 5 μm to 60 μm range are believed to provide superior results in at least many applications” (FF 14). Thus, Gratz discloses a medical device with a coating layer thickness that encompasses Appellant’s claimed coating thickness. See Iron Grip Barbell Co., 392 F.3d at 1322 (“[W]here there is a range disclosed in the prior art, and the claimed invention falls within that range, there is a presumption of obviousness.”). Therefore, we find no error in Examiner’s conclusion that it would have been prima facie obvious to coat a medical device with a coating layer having a thickness suggested by the combination of Fox and Gratz, which encompasses Appellant’s claimed thickness range. For the foregoing reasons, we are not persuaded by Appellant’s contention that “Examiner . . . failed to allege, much less establish that there would have been an apparent reason, with rational underpinning, that would have caused one of ordinary skill in the art to employ the thicknesses for the coating described by Gratz in the antimicrobial coating described by Fox” (Appeal Br. 13 (footnote omitted); see id. at 13–14; see also Reply Br. 8). Appeal 2020-002588 Application 15/700,446 14 Claim 23: The medical device of Appellant’s claim 23 depends from and further limits claim 1 to require that the at least one water permeable polymer encapsulates the particles of the at least one antimicrobial agent to prevent re-agglomeration of the particles (Appeal Br. 21). As discussed above, with respect to Appellant’s claim 4, we find no error in Examiner’s conclusion that the combination of Fox and Gratz makes obvious the encapsulation of antimicrobial agent particles in the water permeable polymer, i.e., polyurethane, component of a medical device’s coating layer. With respect to Appellant’s claim 23, Examiner further reasons “that the encapsulation of the antimicrobial agent particles via the polyurethane would obviously prevent reagglomeration of the particles” as required by Appellant’s claimed invention (Ans. 24–25). We find no error in Examiner’s rationale. For the foregoing reasons, we are not persuaded by Appellant’s contention that Examiner’s rationale failed to “support the determination that the allegedly inherent characteristic[s] necessarily flows from the teachings of the applied prior art” (Appeal Br. 15). In this regard, we are not persuaded by the factually unsupported assertions of Appellant’s counsel (see id. (Appellant’s counsel contends that “depending on the size of re- agglomerated particles and the overall thickness of a coating, it would appear possible for a coating to contain re-agglomerated particles while also having a smooth coating surface”)). See In re Pearson, 494 F.2d 1399, 1405 (CCPA 1974) (“Attorney’s argument in a brief cannot take the place of evidence.”). Appeal 2020-002588 Application 15/700,446 15 The rejection over Fox and Lin: Appellant’s claim 18 is representative and reproduced above. Based on the combination of Fox and Lin, Examiner concludes that, at the time Appellant’s invention was made, it would have been prima facie obvious to optimize the particle size of Fox’s antimicrobial agent, in Fox’s antimicrobial formulation, to have an average size of about 5–50 microns (see Ans. 14). We find no error in Examiner’s prima facie case of obviousness. As discussed above, with respect to Appellant’s claim 1, Fox discloses the use of an antimicrobial agent, i.e., silver sulfadiazine, “having a particle size of 5μ[m] or less” or a larger average particle size “depending on the contemplated use of the medical device” (FF 5). A 5 μm or larger average particle size encompasses an average particle size of about 5 microns to about 50 microns, as set forth in Appellant’s claimed invention. See Iron Grip Barbell Co., 392 F.3d at 1322 (“[W]here there is a range disclosed in the prior art, and the claimed invention falls within that range, there is a presumption of obviousness.”). Therefore, we are not persuaded by Appellant’s contentions regarding particle size (see Appeal Br. 16; see also Reply Br. 11–12).7 7 Because Fox makes obvious Appellant’s claimed invention, we do not rely on Lin. The Board may rely upon less than all the references cited by the Examiner. See In re May, 574 F.2d 1082, 1090 (CCPA 1978); In re Kronig, 539 F.2d 1300, 1304 (CCPA 1976). Appeal 2020-002588 Application 15/700,446 16 New Claim Groupings: We recognize that Appellant’s Reply Brief presents “new” claim groupings and arguments with respect to Appellant’s claims 21 and 22, which were previously included the first claim grouping in Appellant’s Appeal Brief (see Reply Br. 8–11; cf. Appeal Br. 5). Appellant’s claims 21 and 22 relate to the particle size of the antimicrobial (see generally Appeal Br. 21). Appellant’s Appeal Brief, expressly addresses antimicrobial particle size and, thus, Appellant could have, but chose not to, separately argue claims 21 and 22 in Appeal Brief (see, e.g., Appeal Br. 7–9). Thus, we decline Appellant’s invitation to separately consider claims 21–22. See Ex parte Borden, 93 USPQ2d 1473, 1474 (BPAI 2010) (informative) (“[T]he reply brief [is not] an opportunity to make arguments that could have been made in the principal brief on appeal to rebut the Examiner’s rejections, but were not.”). CONCLUSION The preponderance of evidence relied upon by Examiner supports a conclusion of obviousness. The rejection of claims 1, 4, 17, and 23 under 35 U.S.C. § 103(a) as unpatentable over the combination of Fox, Lin, and Gratz is affirmed. Claims 2, 3, 5–9, 13–16, 21, and 22 are not separately argued and fall with claim 1. The rejection of claims 18–20 under 35 U.S.C. § 103(a) as unpatentable over the combination of Fox and Lin is affirmed. Claims 19 and 20 are not separately argued and fall with claim 18. Appeal 2020-002588 Application 15/700,446 17 DECISION SUMMARY In summary: Claims Rejected 35 U.S.C. § Reference(s)/Basis Affirmed Reversed 1–9, 13–17, 21–23 103 Fox, Lin, Gratz 1–9, 13– 17, 21–23 18–20 103 Fox, Lin 18–20 Overall Outcome 1–9, 13– 23 TIME PERIOD FOR RESPONSE No time period for taking any subsequent action in connection with this appeal may be extended under 37 C.F.R. § 1.136(a). AFFIRMED