Chiome Bioscience Inc.

Patent Trials and Appeals Board

Feb 18, 2022

2021004172 (P.T.A.B. Feb. 18, 2022)

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. 15/308,085 10/31/2016 Shuichi Hashimoto WNGR001.003APC 7781 20995 7590 02/18/2022 KNOBBE MARTENS OLSON & BEAR LLP 2040 MAIN STREET FOURTEENTH FLOOR IRVINE, CA 92614 EXAMINER NGUYEN, QUANG ART UNIT PAPER NUMBER 1633 NOTIFICATION DATE DELIVERY MODE 02/18/2022 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): efiling@knobbe.com jayna.cartee@knobbe.com PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE BEFORE THE PATENT TRIAL AND APPEAL BOARD Ex parte SHUICHI HASHIMOTO, TOMOAKI UCHIKI, SHIGEHISA KAWATA, KENJIRO ASAGOSHI, TAKASHI YABUKI, HITOMI SANO, SHUNSUKE MIYAI, NAOKI TAKAHASHI, AKI TAKESUE and ATSUSHI SAWADA Appeal 2021-004172 Application 15/308,085 Technology Center 1600 Before DEBORAH KATZ, ULRIKE W. JENKS, and TAWEN CHANG, Administrative Patent Judges. JENKS, Administrative Patent Judge. DECISION ON APPEAL Pursuant to 35 U.S.C. § 134(a), Appellant1 appeals from Examiner’s decision to reject claims drawn to a recombinant chicken B cell. 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(a). Appellant identifies the real party in interest as application, Chiome Bioscience Inc. Appeal Br. 3. Appeal 2021-004172 Application 15/308,085 2 STATEMENT OF THE CASE The process of generating monoclonal antibodies takes time and effort and can at times induce immunological tolerance. Spec. ¶ 3. Phage display libraries have been created and serve as a technique for overcoming the problem regarding immunological tolerance, and does not utilize in vivo immunity. Id. The ADLib system avoids “immunological tolerance, which is an advantage of an in vitro system antibody production technique, and in that a complete IgM antibody can be promptly obtained.” Id. ¶ 4. In order to utilize antibodies as pharmaceuticals it is important that the antibody be compatible with the animal species. Id. ¶ 5. In the case of animals such as a chicken, a rabbit, a bovine or sheep, there is a region in which “pseudogenes” are gathered, upstream of an antibody variable region. The sequence of the respective pseudo genes are similar to that of antibody variable region and are not translated by themselves. All or a part of variable region sequences are rewritten by pseudogene sequences by a phenomenon referred to as gene conversion, so that a variety of sequences are generated. Diversification of antibodies occurs as a result of V(D)J recombination in animals such as a human or a mouse. In contrast, in animals such as a chicken, a rabbit, a bovine or sheep, such diversification of antibodies occurs by a mechanism referred to as gene conversion that is completely different from the recombination. Id. ¶ 6. According to the Specification, the term “pseudogene” is used to mean a DNA sequence that is similar to a functional gene but does not function as an expressing gene. . . . A pseudogene is not present in an antibody gene locus in human genome, but in the present description, a DNA sequence having a sequence similar to a human antibody variable region, which has been introduced into a chicken antibody gene locus for the purpose of causing gene conversion Appeal 2021-004172 Application 15/308,085 3 with the inserted human antibody variable region, is collectively referred to as a “human pseudo gene.” Id. ¶ 15. CLAIMED SUBJECT MATTER The claims2 are directed to a chicken B cell. Claim 1, reproduced below, is the sole independent claim and illustrative of the claimed subject matter: 1. A chicken B cell, in which the chicken antibody light chain gene locus is replaced by a DNA sequence derived from a human antibody light chain variable region and by a DNA sequence derived from a human antibody light chain constant region, which in the chicken antibody heavy chain gene locus all or a part of a DNA sequence derived from a human antibody heavy chain variable region and of a human antibody heavy chain constant region are inserted, and in which the chicken antibody light chain pseudogene locus is replaced by 30 or more DNA sequences derived from human antibody light chain variable regions, and in which the chicken antibody heavy chain pseudogene locus is inserted by 30 or more DNA sequences derived from human antibody heavy chain variable regions, wherein the chicken B cell has the ability to express a human antibody on the cell surface and also to secrete the human antibody into the culture solution, and wherein a complementarity-determining region 3 (CDR3) encoded by the human antibody light chain and heavy chain variable regions comprises more than 5 different amino acids. Appeal Br. 16 (Claims Appendix). 2 Claims 18-20 and 22 are withdrawn from consideration because they are directed to non-elected invention. Final Act. 2. Appeal 2021-004172 Application 15/308,085 4 REJECTIONS Grounds3 of rejection before this Panel for review: I. Claims 1, 6, 8, 9, 11, and 17 under 35 U.S.C. 103 as being obvious over Harriman4 in view of Kanayama,5 Chiome,6 and Hufton;7 and II. Claims 12-16 under 35 U.S.C. 103 as being obvious over Harriman in view of Kanayama, Chiome, Hufton, and Ohta8 as evidenced by Tsai.9 OPINION I. Obviousness over Harriman, Kanayama, Chiome, and Hufton The issue is whether the preponderance of evidence of record supports Examiner’s conclusion that the combination of references renders the recombinant chicken B cell obvious. A. Findings of fact (FF) We agree with and adopt the findings concerning the scope and content of the prior art as well as conclusion as set forth in Examiner’s Answer and Final Office Action. The findings of fact reproduced below are referenced to highlight certain pertinent evidence. 3 Herein, we refer to the Final Office Action mailed February 28, 2020 (“Final Act.”); Appeal Brief filed on March 12, 2021; Examiner Answer mailed April 28, 2021 (“Ans.”); and Appellant’s Reply Brief filed June 22 2021 (“Reply Br.”). 4 Harriman et al., A1 WO 2011/019844, issued February 17, 2011. 5 Kanayama et al., US 2013/0244907 A1, published September 19, 2013. 6 Chiome Bioscience Inc. Announcement dated December 12, 2012 (English translation version; IDS). 7 Hufton et al., US 2010/0143349 A1, published June 10, 2010. 8 Ohta et al., EP 1 536 004 A1, published June 1, 2005. 9 Tsai et al., US 2008/0300205 A1, published Dec. 4, 2008. Appeal 2021-004172 Application 15/308,085 5 FF1. Hufton teaches the structure and nomenclature associated with an antibody. Intact antibodies, also known as immunoglobulins, are typically tetrameric glycosylated proteins composed of two light (L) chains of approximately 25 kDa each and two heavy (H) chains of approximately 50 kDa each. Two types of light chain, termed lambda and kappa, are found in antibodies. Depending on the amino acid sequence of the constant domain of heavy chains, immunoglobulins can be assigned to five major classes: A, D, E, G, and M, and several of these may be further divided into subclasses (isotypes), e.g., IgG1, IgG2, IgG3, IgG4, IgA1, and IgA2. Each light chain is composed of an N terminal variable (V) domain (VL) and a constant (C) domain (CL). Each heavy chain is composed of an N-terminal V domain (VH), three or four C domains (CHs), and a hinge region. The CH domain most proximal to VH is designated as CH1. The VH and VL domains consist of four regions of relatively conserved sequences called framework regions (FR1, FR2, FR3, and FR4), which form a scaffold for three regions of hypervariable sequences (complementarity determining regions, CDRs). The CDRs contain most of the residues responsible for specific interactions of the antibody with the antigen. CDRs are referred to as CDR1, CDR2, and CDR3. Accordingly, CDR constituents on the heavy chain are referred to as HI, H2, and H3, while CDR constituents on the light chain are referred to as LI, L2, and L3. CDR3 is the greatest source of molecular diversity within the antibody binding site. H3, for example, can be as short as two amino acid residues or greater than 26 amino acids. The subunit structures and three-dimensional configurations of different classes of immunoglobulins are well known in the art. . . . One of skill in the art will recognize that each subunit structure, e.g., a CH, VH, CL, VL, CDR, FR structure, comprises active fragments, e.g., the portion of the VH, VL, or CDR subunit that binds to the antigen, i.e., the binding fragment, or, e.g., the portion Appeal 2021-004172 Application 15/308,085 6 of the CH subunit that binds to and/or activates, e.g., an Fc receptor and/or complement. Hufton ¶ 81. FF2. Hufton teaches that the antibody binding to a target can be optimized using a variety of techniques. Optimization can be explored via targeted or nontargeted mutagenesis of an antibody with desired characteristics. In targeted mutagenesis, specific areas known to be associated with affinity and specificity are preferentially mutated. VH-CDR3 is a primary target in this procedure as it is situated at the center of the antibody combining site and is the most naturally diverse loop in the immune repertoire. Targeted mutations can be incorporated into the VH-CDR3 or other loops like VL- CDR3 using “spiking” ‘parsimonious’ or “randomization” procedures which incorporate an increasing mutational load with the loop being targeted. Id. ¶ 141. FF3. Harriman teaches that “[c]himeric antibodies are antibodies whose light and heavy chain genes have been constructed, typically by genetic engineering, from antibody variable and constant region genes belonging to different species.” Harriman 7. “A ‘variable region’ of a heavy or light antibody chain is an N-terminal mature domain of the chain that contains CDR1, CDR2 and CD[R]3, and framework regions.” Id. at 8. Harriman teaches an engineered chicken to produce antibodies containing a human framework. Id. at 32 (Example 1). Harriman teaches that “[t]he antibodies produced by the transgenic animal are therefore encoded by whatever sequences are donated from the pseudogene variable regions to the variable region of the functional gene.” Id. at 13. “[T]he amino acid sequence of all of the FR1 [, FR2, FR3, and FR4] regions encoded by the pseudogenes Appeal 2021-004172 Application 15/308,085 7 may be identical to the FR1 [, FR2, FR3, and FR4] region encoded by the transcribed variable domain.” Id. Gene conversion of an array of VL pseudo genes where all pseudo genes have an identical framework region and the CDRs are composed of random arrays of serine, tyrosine, alanine and aspartate will be demonstrated using DT40 cells from a virally transformed chicken pre-B cell line that continues to diversify the light chain by gene conversion in vitro. Furthermore, DT40 cells undergo high rates of homologous recombination which provides a straightforward route for replacement of the chicken functional variable region with a recombinant variable region. Id. at 32. Harriman teaches that “DT40 cells undergo high rates of homologous recombination which provides a straightforward route for replacement of the chicken functional variable region with a recombinant variable region.” Id. at 32 (Example 1). FF4. Harriman teaches that the CDRs may vary in length, with CDR1 having a length of 6-12 amino acids, CDR2 having a length of 4-12 amino acids, CDR3 having a length of 5-11 amino acids. See id. at 15-16. [R]eplacing the variable regions in the endogenous immunoglobulin heavy chain locus of the animal with a) a heavy chain variable region encoding: i. light chain CDRl, CDR2 and CDR3 regions that are composed of the 2 to 5 different amino acids; and ii. heavy chain framework regions; and b) a plurality of pseudogene heavy chain variable regions each encoding: i. heavy chain CDRl, CDR2 and CDR3 regions that are composed of the 2 to 5 different amino acids; and ii. heavy chain framework regions that are identical to the corresponding framework regions encoded by the heavy chain variable region. Upon integration of the construct, the variable region becomes the transcribed variable region of the functional Appeal 2021-004172 Application 15/308,085 8 immunoglobulin locus of the transgenic animal, and the pseudogene V regions alter the sequence of the transcribed variable region by gene conversion. Gene conversion may result in the contribution of small (eg 1-10 nucleotides), moderate (10-30 nucleotides), or large (>30 nucleotides) segments of DNA from one or more of the donor pseudogenes to the transcribed V region. Gene conversion can transpire over many iterations, so multiple pseudo-V’s may contribute sequence to the actively expressed V gene. Since the process of gene conversion is highly variable in terms of which pseudogenes are selected, and the extent to which each is utilized in a given lymphocyte, a large and diverse antibody repertoire will result in the transgenic animal. Id. at 18-19. According to Harriman, “the resultant antibodies produced by the transgenic animal may have light and/or heavy chain CDRs that are solely composed of the 2 to 5 different amino acids.” Id. at 16. FF5. Harriman teaches that “[t]he number of introduced pseudogene variable regions present at the light and/or heavy chain locus may vary and, in particular embodiments, may be in the range of 5-30, e.g., 10 to 25.” Id. at 17. FF6. Kanayama teaches converting DT40-SW cells to human-type antibody- producing cells by substituting a chicken antibody gene with a human antibody gene by high-frequency homologous recombination, one of the characteristics of DT40 cells. . . . Particularly, . . . the substitution of a constant region with a human-type constant region while leaving a variable region, into which a mutation is introduced, is left as it is (chicken variable region) in order to construct a useful antibody library effectively utilizing the mutation capacity of DT40 cells. . . . An antibody to be produced herein is a chicken-human chimeric antibody. Since the constant region thereof is derived from a human, Appeal 2021-004172 Application 15/308,085 9 and thus the antibody can be directly used for various tests for searching candidate medicines, enabling accelerated candidate search. . . . A human-type antibody to be produced herein is preferably an IgG1 antibody that can be expected to exhibit various effector functions via in vivo heavy chain constant region. The present inventors have established herein human IgG 1 -producing DT 40- SW and have used the K chain, the amount of which existing in vivo in a human is the highest over the other parts, as a light chain constant region. Kanayama ¶ 26. FF7. Chiome discloses introducing human antibody genes into a chicken B cell including into the light and heavy pseudogene loci of chicken. The figure below shows a three-step process for making such a recombinant chicken B cell. The figure reproduced above shows the introduction of a human antibody gene into the variable and constant regions of the heavy and Appeal 2021-004172 Application 15/308,085 10 light chain in a DT-40 cell. In addition, the figure shows the introduction of a human antibody gene into the light and heavy chain pseudogene loci/variable region. The figure shows that at each stage you need to verify that the genes are expressed, and once human genes are inserted into the pseudogene loci check that light and heavy chain recombination is occurring. Chiome 2. B. Analysis Examiner finds that Harriman teaches a transgenic chicken that contains light chains comprising a transcribed light chain variable region, a light chain frame work, operably linked to the functional immunoglobulin light chain gene, as well as heavy chains comprising a transcribed heavy chain variable region, a heavy chain frame work, operably linked to the functional immunoglobulin heavy chain gene. Final Act. 6; FF3-FF5. According to Examiner, Harriman et al. also stated clearly and explicitly “In certain cases, the CDR regions encoded by the light chain variable domains, and/or the heavy chain variable domain may be composed of only 2 to 5 (i.e., 2, 3, 4, or 5) different amino acid residues, where, in this context, the term ‘composed of’ is intended to mean that each individual amino acid position within a CDR is occupied by a single amino acid residue independently chosen from a group of 2 to 5 amino acid residues . . . CDRs may vary in length. In certain embodiments, the heavy chain CDR1 may be in the range of 6 to 12 amino acid residues in length, the heavy chain CDR2 may be in the range of 4 to 12 amino acid residues in length, the heavy chain CDR3 may be in the range of 3 to 25 amino acid residues in length. Final Act. 6-7 (emphasis omitted). Examiner finds that Harriman “also demonstrated the expression of human immunoglobulin variable regions in the chicken DT40 B cell line and the further diversification of these genes by Appeal 2021-004172 Application 15/308,085 11 gene conversion in a cell-cultured based method.” Final Act. 8 (citing Harriman Examples 1-9). Examiner acknowledges that Harriman does not teach replacing the light or heavy chain pseudogene locus with more than 30 DNA sequences derived from human antibody light or heavy chain variable regions respectively. Final Act. 8; FF5; Ans 17 (overlapping endpoint). Examiner relies on Kanayama for substituting chicken light and heavy chain constant regions with human K constant region and human Y constant regions to produce an IgG1 antibody. Final Act. 9; FF6. Examiner relies on Chiome for the production of “a chicken DT40 cell strain in which the pseudogene, variable region and constant region involved with the heavy chain antibody genes are converted into human genes, as well as confirmed gene conversion occurred on the heavy chain.” Final Act. 9; FF7. Examiner relies on Hufton to establish “that CDRs (CDR1, CDR2 and CDR3) contain most of the residues responsible for specific interactions of the antibody with the antigen; and also stated ‘CDR3 is the greatest source of molecular diversity within the antibody-binding site. H3, for example, can be as short as two amino acid residues or greater than 26 amino acids.’” Final Act. 9- 10; FF1-2. Based on these disclosures, Examiner concludes that it would have been obvious for an ordinary skilled artisan before the effective filing date of the present application to modify the teachings of Harriman because Chiome already announced the successful generation of a chicken DT40 cell strain in which the pseudogene, variable region and constant region involved with the heavy chain antibody genes are converted into human genes, as well as confirmed gene conversion occurred on the heavy chain. Moreover, since Hufton et al disclosed that CDR3 is the greatest source of molecular diversity within the antibody-binding site, a CDR3 region encoded by the human antibody light chain and heavy chain Appeal 2021-004172 Application 15/308,085 12 variable regions comprising more than 5 different amino acids would facilitate the generation of more diverse antibodies. Final Act. 11 (emphasis omitted); see FF1-FF7. In addition, Examiner finds that Harriman already teaches that ‘“[t]he number of introduced pseudogene variable regions present at the light and/or heavy chain locus may vary and, in particular embodiments, may be in the range of 5-30, e.g., 10 to 25’; and ‘CDRs may vary in length.” Final Act. 11; see Ans. 17. Appellant contends that Examiner has not set out a prima facie case of obviousness. Appeal Br. 6-15. Specifically, Appellant contends that the missing elements include 1) a human antibody heavy chain variable region and a human antibody heavy chain constant region inserted into the chicken heavy chain gene locus (Appeal Br. 7), 2) replacement of the chicken antibody light (or heavy) chain pseudogene locus with 30 or more DNA sequences (id.), 3) a chicken B cell that has the ability to express a human antibody on the cell surface or secrete into solution (id.), and 4) “a complementarity-determining region 3 (CDR3) encoded by the human antibody light chain and heavy chain variable regions comprises more than 5 different amino acids” (id. at 8; see Reply Br. 3 (Harriman is limited to only including 2 to 5 different amino acids in CDR regions)). Finally, Appellant argues that 5) the claimed subject matter exhibits unexpected results (Appeal Br. 14-15 (arguing “the design of pseudogene regions in the present application is truly inventive and have an unexpected and surprising effect”)). We address Appellant’s contentions below: 1) Insertion of Human Genes into a Chicken Gene Locus We are not persuaded by Appellant’s contention that the combined references are missing the element of inserting human genes into a chicken gene locus. As Examiner explains, “Kanayama et al already successfully Appeal 2021-004172 Application 15/308,085 13 prepared at least chicken DT40-SE cells displaying a chicken-human chimeric IgG1 antibody on cell surfaces and to secrete the same in a culture supernatant, wherein the DT40-SW cells are converted by substituting chicken light and heavy chain constant regions with human K constant region and human y constant regions, respectively.” Ans. 7; FF6. This is further supported by Chiome that shows the introduction of human genes into both the variable and constant region in a DT-40 cell, which is a chicken B cell. See Ans. 7, FF7. 2) Replacement of Chicken Pseudogenes We are not persuaded by Appellant’s contention that the combination of references is missing the replacement of the pseudogene locus with 30 or more DNA sequences. Chiome teaches the introduction of human antibody heavy or light chain genes into the respective chicken heavy or light chain pseudogene locus. FF7; see Chiome 3. Examiner finds Harriman already suggests that ‘“[t]he number of introduced pseudogene variable regions present at the light and/or heavy chain locus may vary and, in particular embodiments, may be in the range of 5-30, e.g., 10 to 25’; and ‘CDRs may vary in length. In certain embodiments, the heavy chain . . . CDR3 may be in the range of 3 to 25 amino acid residues in length, the light chain . . . CDR3 may be in the range of 5 to 11 amino acid residues in length, although antibodies having CDRs of length outside of these ranges are envisioned.’” Ans. 8, see id. at 13, 17 (“Harriman already taught that the number of introduced pseudogene variable regions present at the light and/or heavy chain locus may vary and including in the range of 5-30.”). In cases involving overlapping ranges, we and our predecessor court have consistently held that even a slight overlap in range establishes a prima facie case of obviousness. . . . We have also held that a prima facie case of obviousness exists when the Appeal 2021-004172 Application 15/308,085 14 claimed range and the prior art range do not overlap but are close enough such that one skilled in the art would have expected them to have the same properties. In re Peterson, 315 F.3d 1325, 1329 (Fed. Cir. 2003). We find no error with Examiner’s reliance that Harriman teaches an endpoint that overlaps with the claimed range rendering the claims obvious. 3) Antibody Expression in a Chicken B Cell We are not persuaded by Appellant’s contention and agree with Examiner that Kanayama “successfully prepared at least chicken DT40-SE cells displaying a chicken-human chimeric IgG1 antibody on cell surfaces and to secrete the same in a culture supernatant.” Ans. 6; FF6. According to Examiner, the human-type antibody produced in Kanayama is preferably an IgG1 antibody “that can be expected to exhibit various effector functions via in vivo heavy chain constant region.” Ans. 14 (citing Kanayama ¶ 26); FF6; see Kanayama, Fig. 3. Examiner additionally finds that Chiome further supports the production of antibody from DT40 cells that have the pseudogene, variable region and constant region involved with the heavy chain antibody genes converted into human genes. Ans. 14-15. Chiome teaches “chicken DT 40 cell strain in which the pseudogene, variable region and constant region involved with the heavy chain antibody genes are converted into human genes, as well as confirmed gene conversion occurred on the heavy chain.” Ans. 6; FF7; see Chiome 3. We agree with Examiner’s conclusion that the evidence of record supports a finding that DT-40 transformed cells can produce antibodies that are expressed on the cell surface or that are secreted into the supernatant. Appeal 2021-004172 Application 15/308,085 15 4) More Than 5 Different Amino Acids in the Variable Region Appellant contends there is yet another missing claim element. Specifically, the claim requires “a complementarity-determining region 3 (CDR3) encoded by the human antibody light chain and heavy chain variable regions compris[ing] more than 5 different amino acids.” Appeal Br. 8; see also Reply Br. 3 (Harriman is limited to only including 2 to 5 different amino acids in the CDR region)). At oral hearing Appellant emphasized that Examiner may have confused the 5 amino acids claim requirement with respect to CDR3 as being a length requirement rather than a requirement of having different kinds of amino acids represented. Tr. 18:14-15 (“So we’re talking about the type of amino acid.”). We are not persuaded by Appellant’s contention that the combination of references fails to teach the use of more than 5 different amino acids. The evidence supports that the CDR3 has a length of greater than 5 amino acids. According to Examiner, Hufton teaches that “CDR3 is the greatest source of molecular diversity within the antibody-binding site. H3, for example, can be as short as two amino acid residues or greater than 26 amino acids.” Final Act. 9-10 (emphasis omitted). Harriman supports Hufton’s teachings the CDRs may vary in length, with CDR1 having a length of 6-12 amino acids, CDR2 having a length of 4-12 amino acids, CDR3 having a length of 5-11 amino acids. See FF4. When you have an amino acid chain that has a length of 5-11 amino acids, it is reasonable to conclude that any one of the amino acids in the chain can be represented by any one of the 20 naturally occurring amino acids. We understand that Harriman exemplified CDR3 constructs with only 3 amino acids tyrosine (Y), serine (S), and tryptophan (W) in proportions of 40/50/10%, respectively. See Harriman 33 (Table 1). This, however, does Appeal 2021-004172 Application 15/308,085 16 not mean that the CDR regions encoded by the variable domain can only be represented by 3 different amino acids. Harriman clearly teaches that “the heavy chain variable domain may be composed of only 2 to 5 (i.e., 2, 3, 4, or 5) different amino acid residues, . . . [with] at least one of the 2 to 5 amino acids is a bulky amino acid such as a tyrosine or tryptophan residue, and at least one of said 2 to 5 amino acids is a small amino acid residue such as an alanine, glycine or serine residue.” Id. at 16. Here, Harriman exemplifies CDR3 having a length of 6 amino acids that are represented by 3 different amino acids. Id. at 33 (Table 1). By listing 5 different amino acid as a possible insertion at each position in the CDR, Harriman clearly suggests a range that is so close to the claimed range that one skilled in the art would have expected that including additional amino acids would have the same properties. See Peterson, 315 F.3d at 1329. According to Examiner, even if Harriman does not teach using CDR3 encoded by the human antibody light chain and heavy chain variable region compris[ing] more than 5 different amino acids, since Hufton et al disclosed that CDR3 is the greatest source of molecular diversity within the antibody binding site, [one ordinarily skilled] in the art would readily recognize that a CDR3 region encoded by the human antibody light chain and heavy chain variable regions comprising more than 5 different amino acids would facilitate the generation of more diverse antibodies. Ans. 16 (emphasis omitted). We agree with Examiner that the combination of Harriman and Hufton would suggest that CDRs could be represented by more than 5 different kinds of amino acids in order to provide diverse antibody structures. A claimed invention is rendered prima facie obvious by the teachings of a prior art reference that discloses a range that touches the range recited in the claim. In re Geisler, 116 F.3d 1465, 1469 (Fed. Cir. 1997), citing In re Appeal 2021-004172 Application 15/308,085 17 Malagari, 499 F.2d 1297, 1303, (CCPA 1974). “In cases involving overlapping ranges, we and our predecessor court have consistently held that even a slight overlap in range establishes a prima facie case of obviousness. . . . We have also held that a prima facie case of obviousness exists when the claimed range and the prior art range do not overlap but are close enough such that one skilled in the art would have expected them to have the same properties.” Peterson, 315 F.3d at 1329. Harriman’s teaching of using a range of 2 to 5 different amino acid residues is close enough to render the claimed range of “more than 5 different amino acids” obvious. Such a prima facie case may be rebutted “by establishing that the claimed range is critical, generally by showing that the claimed range achieves unexpected results relative to the prior art range.” Peterson, 315 F.3d at 1330 (citations omitted). We find no evidence in the record that shows that the use of 6 different amino acids produces a markedly different result than 5 different amino acids. See Tr. 20:3-21:17. Accordingly, we are not persuaded by Appellant’s contention that there is a missing element in Examiner’s rejection based on the combination of Harriman, Kanayama, Chiome, and Hufton that renders the claims non- obvious. 5) Unexpected Results We agree with Examiner that Appellant’s reliance on unexpected results is insufficient to overcome Examiner’s prima facie showing of obviousness. We observe that objective indicia of nonobviousness, such as unexpected results, are “only relevant to the obviousness inquiry ‘if there is a nexus between the claimed invention and the [objective indicia].’” In re Affinity Labs of Tex., LLC, 856 F.3d 883, 901 (Fed. Cir. 2017) (quoting Ormco Corp. v. Align Tech., Inc., 463 F.3d 1299, 1312 (Fed. Cir. 2006)). Appeal 2021-004172 Application 15/308,085 18 Examiner explains “that any unexpected and surprising result if existed must be commensurate with the scope of the claims.” Ans. 18. Examiner notes that “Appellants stated that the design of pseudogene regions in the present application is truly inventive and has an unexpected and surprising effect over Harriman.” Id. Examiner finds, and we agree, that the evidence provided in the Specification is not sufficient to establish that it is the structure of the DNA sequences in the pseudogene locus and not the incubation with trichostatin A (TSA) that is providing the beneficial effect. Examiner notes that antibodies generated to Plexin A4 and Semaphorin 3A from cell lines that had 15 pseudogenes inserted into the light and heavy chain, while antibodies to IL-8 were generated from cells that had 30 pseudogenes inserted into the light and heavy chain. See Ans. 18. These results presented in the Specification, according to Examiner are insufficient to show a difference between 15 and 30 pseudogene insertion, because antibodies were produced against the various targets regardless of the number of pseudogenes inserted. Examiner further notes that all cell lines were incubated with TSA and all produced antibodies but such a treatment is not required by the claim. See Ans. 18. Because cell lines having both 15 and 30 pseudogene insertions produced antibodies, we agree with Examiner that the Specification has not established that it is the structure of “30 or more DNA sequences” produces anything unexpected. Accordingly, we find that the evidence of unexpected results is not sufficient to overcome Examiner’s prima facie conclusion of obviousness. C. Conclusion Considering the totality of the cited evidence and arguments, we conclude that the preponderance of the evidence supports Examiner’s conclusion of obviousness with respect to claim 1, and Appellant has not Appeal 2021-004172 Application 15/308,085 19 provided persuasive rebuttal evidence or evidence of unexpected results that, when considered together with the evidence of obviousness, shows the claims to be non-obvious. As Appellant does not argue the claims separately, claims 6, 8, 9, 11, and 17 fall with claim 1. 37 C.F.R. § 41.37 (c)(1)(iv). II. Obviousness over Harriman, Kanayama, Chiome, Hufton, and Otha Appellant does not separately argue the claims in this obviousness rejection. See Appeal Br. 6. Having affirmed the rejection of claim 1 over Harriman, Kanayama, Chiome, and Hufton for the reasons given above, we find that the further combination with Otha renders claims 12-16 obvious for the reasons given by Examiner in the Final Office Action and Answer. DECISION SUMMARY In summary: Claims Rejected 35 U.S.C. § Reference(s)/Basis Affirmed Reversed 1, 6, 8, 9, 11, 17 103 Harriman, Kanayama, Chiome, Hufton 1, 6, 8, 9, 11, 17 12-16 103 Harriman, Kanayama, Chiome, Hufton, Otha, Tsai 12-16 Overall Outcome 1, 6, 8, 9, 11-17 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). See 37 C.F.R. § 1.136(a)(1)(iv). AFFIRMED