Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
DETAILED ACTION
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
This action is in response to the papers filed on June 25, 2026.
Election/Restrictions
Applicant's election with traverse of Group II, drawn to a eukaryotic host cell, method of making the cell, and a vector system, previously acknowledged and made FINAL. Claims 1-6 and 17 were previously withdrawn from further consideration pursuant to 37 CFR 1.142(b), as being drawn to a nonelected groups of inventions.
Therefore, claims 7-16 and 18 are currently under examination.
Priority
The present application, filed on May 13, 2022, is a 35 U.S.C. 371 national stage filing of the International Application No. PCT/EP2020/081923, filed November 12, 2020. Acknowledgment is made of applicant’s claim for foreign priority under 35 U.S.C. 119 (a)-(d). The certified copy has been filed in parent European Patent Application EP19209232.8, filed November 14, 2019, and EP20185798.4, filed July 14, 2020. Receipt is acknowledged of priority documents EP19209232.8 and EP20185798.4 required by 37 CFR 1.55.
Thus, the earliest possible priority for the instant application is November 14, 2019.
Claim Interpretation
The claims are directed to a eukaryotic cell comprising “exogenous” nucleic acids. Under the broadest reasonable interpretation, consistent with the specification, the term “exogenous” refers to any nucleic acid or material that is introduced into the cell from outside the cell or produced inside the cell prior to introduction, regardless of whether the sequence itself is naturally occurring or identical to an endogenous sequence. As expressly defined in the Specification, an “exogenous nucleic acid” includes nucleic acids that are not naturally produced in the cell, as well as nucleic acids whose sequences may also be found endogenously in the same organism or cell, provided they are introduced into the cell or are under non-native regulatory control (see instant specification, pg. 8, para. 1). Under the broadest reasonable interpretation, claim 11 recites “exogenous nucleic acids” and encompasses introduced copies of PAH, GCH1, and the product-encoding sequence regardless of whether identical or homologous sequences are endogenously present in the host cell, including where such nucleic acids are integrated into the genome or operably linked to non-native regulatory elements. Therefore, it is not limited to non-naturally occurring or non-endogenous gene sequences.
Under this definition, a nucleic acid encoding an enzyme which is also endogenously encoded in the host cell encompasses an “exogenous” nucleic acid when introduced by techniques such as transformation, transfection, or integration, such as where the introduced nucleic acid is operably linked to a heterologous or constitutively active promoter. Thus, the ordinary artisan would reasonably understand “exogenous” to encompass introduced copies of native genes, modified variants thereof, truncated forms, or identical coding sequences placed under different regulatory elements, and would not interpret the term as limited to non-naturally occurring sequences or sequences absent from the host organism.
Modified & Maintained Claim Rejections - 35 USC § 103
Claims 7-16 and 18 remain rejected under 35 U.S.C. 103 as being unpatentable over Ding et al. (Mol Ther. 2008 Apr; l6(4):673-81. Epub 2008 Mar 11., see IDS), in view of Hiller et al. (US 2020/0056190 A1, filed March 16, 2017; prior published September 20, 2018, WO 2018/167621, see IDS), and further in view of Daubner et al. (Arch Biochem Biophys. 1997 Dec 15;348(2):295-302.) and Luo et al. (WO 2017/167866 A1, see IDS).
Regarding claims 7-9 and 18, Ding teaches a eukaryotic host cell comprising exogenous nucleic acids encoding phenylalanine hydroxylase (PAH), GTP cyclohydrolase I (GCH1), along with third and 6-pyruvoyltetrahydrobiopterin synthase (PTPS) introduced via vector systems to enable phenylalanine hydroxylation through coordinated expression of PAH and BH4-biosyntnetic enzymes, under the independent control sequences, the CMV promoter (Abstract; pg. 674, column 2, para. 1; Table 1-2; Fig. 3-4).
Ding does not explicitly teach the lack of a functional N-terminal regulatory domain or specifically teach where the eukaryotic cell is a Chinese hamster ovary (CHO) cell.
However, before the effective filing date, Hiller teaches the use of PAH-based systems in eukaryotic host cells, including CHO cells, as a tyrosine prototrophy selection marker system (Abstract; [0019]). Hiller teaches the PAH-based systems can be used in eukaryotic host cells, including CHO cells, to confer tyrosine prototrophy and enable growth in tyrosine-deficient media. Hiller explicitly states:
“provided herein is a host cell containing one or more nucleic acid constructs provided herein containing the PAH and PCBD1 genes, wherein the host cell further comprises an exogenous copy of one or more genes selected from the group consisting of… GCH1 ([0163]).
Hiller further teaches that host cells may be genetically modified to alter expression of endogenous PAH, including by mutation or deletion, to enhance reliance on introduced PAH pathway components, and the selection or evaluation based on their ability to proliferate under tyrosine-limiting conditions and control elements, such as enhancers or promoters ([0031-0033]; [0107-0108]). Hence, the teachings of Hiller provide the selection context and host-cell application for PAH/GCH1 constructs, as taught by Ding. The combination of Ding and Hiller establish the host-cell context, selection pressure, and practical application of PAH-centered systems in CHO cells, but do not specifically teach the deletion of the PAH N-terminal domain.
However, the ordinary artisan would have recognized that, while Ding and Hiller teach the use of PAH and GCH1 in eukaryotic host cells and in tyrosine-based selection contexts, the specific form of PAH employed could be modified to optimize function in the engineered systems, further in view of the teachings of Daubner and Luo.
Daubner teaches that phenylamine hydroxylase lacking the N-terminal regulatory domain remains catalytically active and shows no lag (Abstract; pg. 295, column 1, para. 2; pg. 297-298, bridging para.), and Luo teaches that aromatic amino acid hydroxylases may be used as variants or fragments, including N-terminally modified forms, in engineered expression systems (pg. 50, Example 5). Luo also teaches nucleic acids and vectors encoding the corresponding nucleic acids, such as the phenylalanine hydroxylase and GCH1. Luo teaches GCH1 variants of E.coli and provides cells comprising such variants together with a pterin-4a-carbinolamine dehydratase (PCD) and at least one of a tryptophan hydroxylase (TPH), a tyrosine hydroxylase (TH) and a phenylalanine hydroxylase, or PheH. The variant provides for an increased hydroxylation activity of at least one of the TPH, TH and PheH as compared to native E. coli GCH1, used to overcome tyrosine auxotrophy (claim 1; p. 28, lines 21-34).
Before the effective filing date of the instant application, it would have been obvious to the ordinary artisan to employ an N-terminal regulatory domain deficient PAH, as taught by Daubner and Luo, in the PAH/GCH1 host-cell and selection systems taught by Ding and Hiller, with a reasonable expectation of success. The ordinary artisan would have been motivated to do so because Ding and Hiller teach PAH/GCH1 based host-cell and selection systems, while Daubner and Luo teach that N-terminal modification or removal of the PAH regulatory domain is an effective approach to obtaining catalytically competent PAH variants suitable for engineered expression.
Regarding claim 10, the combined teachings of Ding, Hiller, Daubner, and Luo renders claim 7 obvious. Additionally, Hiller teaches the utility of mammalian host cells ([0114]).
Regarding claim 11, the combined teachings of Ding, Hiller, Daubner, and Luo renders claim 7 obvious. Ding additionally teaches the stable introduction of the expression cassettes into the mammalian cells using viral vectors (pg. 678, column 1-2, bridging para.), and Hiller teaches the generation and selection of stable eukaryotic host cells with stable genomic incorporation ([0124]).
Regarding claim 12, the combined teachings of Ding, Hiller, Daubner, and Luo renders claim 7 obvious. Hiller additional explicitly teaches genetically modifying host cells by mutating or deleting endogenous PAH genes or modifying their regulatory sequences to reduce endogenous pathway activity and thereby enhance reliance on introduced PAH-based systems ([0033-0034]; [0107-0108]). As already communicated, Daubner teaches that PAH lacking the N-terminal regulatory domain remains catalytically active, and Luo teaches that a aromatic amino acid hydroxylases may be employed as variants or fragments, including N-terminally modified forms, in engineered systems. Thus, the ordinary artisan would have found it obvious to reduce or abolish endogenous PAH activity in the host cells of Ding and Hiller while employing an N-terminal regulatory domain deficient PAH, as taught by Daubner and Luo, with a reasonable expectation of success of generating the selection marker-based system.
Regarding claims 13-14, the claims further recite a vector system and conventional vector generation elements, such as cloning site/multiple cloning site insertion. The disclosures of vector-based systems by Ding and Hiller have already been communicated, and these are conventionally utilized in the art. For instance, see Hiller’s teachings on the utility of such vectors (claim 9; [0268]; [0272]). Additionally, Hiller plainly states,
“a nucleotide sequence of interest may alternatively, for example, be a sequence which provides a regulatory or structural function (e.g. a promoter or enhancer sequence), or which serves a different purpose, such as a restriction enzyme sequence for cloning purposes (e.g. a nucleotide sequence of interest may be a multiple cloning site” ([0072]).
Hence, before the effective filing date of the instant application, the ordinary artisan would have found it obvious to implement vector based PAH/GCH1 systems of Ding and Hiller comprising conventional vector-generation elements, including cloning sites or multiple cloning sites for insertion of a nucleic acid of interest, as taught by Hiller, with a reasonable expectation of success.
Regarding claims 15-16, the combined teachings of Ding, Hiller, Daubner, and Luo renders claim 7 obvious. Furthermore, Hiller expressly teaches expression, recovery, and purification of the product ([0138-0140]).
Response to Applicants' arguments as they apply to the rejection of Claims 7-16 and 18 under 35 USC § 103
Applicant’s arguments filed June 25, 2026, have been fully considered but they are not persuasive.
At pages 6-10 of the remarks filed on June 25, 2026, Applicants essentially argue the following:
Applicant argues that the Office has not established a prima facie care of obviousness because Ding is directed to treatment of PKU rather than a tyrosine-selection system, Hiller does not specifically teach a PAH/GCH1 selection system, and the Office has not identified reason why a person of ordinary skill would have combined the references. Applicant further argues that Hiller merely lists GCH1 among a number of possible additional genes without providing a working PAH/GCH1 selection example, and that Ding requires PAH, GCH1/GTPCH, and for PTPS for effective treatment where the proposed combination would require removing PTPS.
This argument is not persuasive because, in response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). Here, Ding teaches the coordinated expression of PAH and GTPCH/GCH1 and reports that cells expressing both PAH and GTPCH are capable of metabolizing phenylalanine. Ding further teaches the functional relationship between PAH and GCH1 or GTPCH. Ding teaches that human primary keratinocytes expressing both PAH and GTPCH were capable of metabolizing phenylalanine and explains that BH4 is a limiting cofactor for PAH activity (Abstract; pg. 674, column 2, para. 1; Table 1-2; Fig. 3-4). Ding additionally teaches the construction of an AAV vector, AAV3-PKU4, simultaneously expressing PAH and GTPCH using an IRES-containing expression cassette under a CMV promoter (pg. 675, column 2, para. 1; Fig. 3).
Hiller teaches a eukaryotic host-cell system comprising exogenous nucleic acids for a PAH tyrosine selectable-marker system and for expression of a product of interest. Hiller teaches that the host cell can be a eukaryotic cell, animal cell, mammalian cells, or a CHO cell (Abstract; [0019]; ([0031-0033]). Hiller also teaches that the CHO cells are tyrosine auxotrophs ([0105]). Hiller teaches a tyrosine selectable marker system involving introduction of PAH-containing recombinant nucleic-acid constructs into host cells, and teaches that nucleotide sequences of interest can be coupled to the selection genes so that cells containing the nucleotide sequence of interest can be selected through tyrosine prototrophy ([0065]). Hiller further teaches nucleic-acid constructs comprising a PAH gene, one or more nucleotide sequences of interest, and one or more expression-control sequences, wherein the nucleotide sequence of interest and PAH gene can be operably linked to appropriate expression-control sequences ([0076-0080]). Hiller teaches that a nucleotide sequence of interest can encode a polypeptide such as an antibody, enzyme, peptide hormone, fusion protein, or detectable protein ([0073]). Hiller teaches the linkage of a product of interest sequence with a PAH selection component through plasmid vectors containing PAH-selection genes together with nucleotide sequences encoding an IgG therapeutic product ([0272]). Additionally, Hiller teaches that host cells containing the PAH selection constructs can additionally comprise an exogenous copy of GCH1, among other genes of the tyrosine-metabolism pathway, and states that the cells can exhibit improved tyrosine metabolism and reduced production of undesirable metabolites ([0163]). Hiller further teaches the biochemical basis for selecting GCH1, and that PAH requires tetrahydrobiopterin (BH4) for catalytic activity, mammalian cells synthesize BH4 from GTP, and GCH1 is one of the enzymes participating in BH4 biosynthesis ([0250]).
Thus, Hiller provides an express reason for including GCH1 in a PAH-containing host-cell system, while Ding further establishes that PAH and GTPCH/GCH1 can be coordinately expressed and function together. Applicant’s arguments concerning PTPS is likewise not persuasive. The rejection does not require elimination of PTPS from Ding, Ding teaches the PAH/GTPCH expression and function, including a PAH/GTPCH construct, and Hiller further teaches the tyrosine selection context. Furthermore, the claims recite “comprising” and therefore do not exclude PTPS, PCBD1, or other additional pathway components. Accordingly, Ding’s use of PTPS in particular therapeutic embodiments does not teach away from the claimed PAH/GCH1 combination or negate Ding’s express teaching of coordinated PAH/GTPCH expression.
Applicant argues that Luo does not disclose a PAH lacking a functional N-terminal regulatory domain because Luo Example 5 concerns an N-terminally modified tyrosine hydroxylase rather than PAH. Applicant further argues that Daubner does not remedy the alleged deficiencies of Ding and Hiller because Daubner concerns characterization of truncated PAH and does not disclose GCH1 or a tyrosine-selection system.
Again, this argument is not persuasive because, in response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). Daubner teaches an N-terminally truncated PAH. Daubner teaches a human PAH catalytic domain construct lacking the N-terminal regulatory region and demonstrates catalytically active, retains comparable Vmax, exhibits a lower KM for phenylalanine, and lacks the activation lag observed with full-length PAH (Abstract; pg. 298-299).
Luo Example 5 does teach N-terminal modification of a replated aromatic amino acid hydroxylase, rather than explicitly exemplifying an N-terminally truncated PAH. However, Luo additionally teaches functionally active PheH variants, homologs, and fragments for engineered host cell systems. Luo teaches the use of functionally active PheH variants, homologs, and fragments in engineered host cells, and teaches that modification of GCH1/FolE can enhance aromatic amino-acid hydroxylase activity identifying phenylalanine hydroxylase as an enzyme expected to benefit (pg. 17, para. 1; Table 1). Moreover, Luo also demonstrates that N-terminal modification of a related mammalian aromatic amino-acid hydroxylase can enhance hydroxylase activity in an engineered system (pg. 50, lines 7-27; Examples 5). Luo therefore provides further support for the known use and optimization of aromatic amino-acid hydroxylases and their cofactor pathway. Daubner supplies the specific truncated PAH teaching relied upon in the rejection. Daubner expressly provides the claimed PAH modification and Luo provides further support for the optimization rationale. Thus, the fact that Daubner does not teach GCH1 or a selection system or that Luo does not itself expressly exemplify the claimed truncated PAH does not take into account the teachings, as a whole. The Examiner respectfully submits that patents are relevant as prior art for all they contain. "The use of patents as references is not limited to what the patentees describe as their own inventions or to the problems with which they are concerned. They are part of the literature of the art, relevant for all they contain." In re Heck, 699 F.2d 1331, 1332-33,216 USPQ 1038, 1039 (Fed. Cir. 1983). With that, a reference may be relied upon for all that it would have reasonably suggested to one having ordinary skill in the art, even nonpreferred embodiments. See MPEP § 2123: Merck & Co. v. BiocraftLabs., Inc. 874F.2d 804, 10 USPQ2d 1843 (Fed. Cir. 1989), cert. denied, 493 U.S. 975 (1989); Upsher-Smith Labs. v. Pamlab, LLC, 412 F.3d 1319, 1323, 75 USPQ2d 1213, 1215 (Fed. Cir. 2005).
3.) Applicant argues that there would have been no reasonable expectation of success and that the reported results are unexpected because cells expressing only PAH or GCH1 individually did not grow in tyrosine free medium, cells containing full-length PAH exhibited slow or no recovery, and cells expressing truncated PAH together with GCH1 successfully grew in tyrosine-free medium. Applicant additionally points to Example 5 and Fig. 4 as showing increased viable cell concentration and prolonged culture viability.
This argument is not persuasive. The experimental results cited by Applicant have been considered as evidence of record. However, a reasonable expectation of success does not require absolute predictability or an expectation of the precise degree of improvement ultimately obtained. Applicant is reminded the Court commented that "[r]esponding to concerns about uncertainty in the prior art influencing the purported success of the claimed combination, this Court [in O'Farrell] stated: "[o]bviousness does not require absolute predictability of success ... all that is required is a reasonable expectation of success."' Kubin, 561 F.3d at 1360 (citing In re O'Farrell, 853 F.2d at 903-904). Daubner teaches that N-terminally truncated PAH remains catalytically active and possess favorable kinetic characteristics, while Hiller and Ding provide the teachings supporting use of PAH with GCH1. Ding teaches functional PAH/GTPCH coexpression, and Hiller teaches both a PAH-based tyrosine-selection system and the biochemical relevance of GCH1 to PAH through BH4 biosynthesis ([0163]; [0250]). Thus, these teachings demonstrate that the ordinary artisan would have found a reasonable expectation that the proposed components would retain their relevant biochemical functions when used together.
Moreover, the unexpected results are not commensurate in scope with claims 7-16 and 18. The reported results concern particular CHO host cells and particular constructs containing truncated CHO or human PAH, including deletion of approximately the N-terminal 116 amino acids, together with GCH1 under particular expression and culture conditions. The pending claims are not limited to those particular constructs, host-cell configurations, promoter arrangements, or any specified magnitude of improved recovery, growth, or viability. Example 5 also concerns particular engineered CHO cell pools rather than the full scope of the pending claims.
Additionally, although claim 16 more specifically recites culture at a tyrosine level below that required for cells not expressing the exogenous PAH and GCH1 enzymes, Hiller expressly teaches culturing and selecting engineered cells in tyrosine-deficient medium, including medium containing 0 µM tyrosine ([0105]; [0146-0148]; [0158]).
Conclusion
Claims 7-16 and 18 are rejected. No claims are allowed.
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JOEL D LEVIN whose telephone number is (571)270-0616. The examiner be reached 8:00 am to 5:00 pm, Monday through Friday.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Christopher Babic can be reached at (571) 272-8507. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/J.D.L./Examiner, Art Unit 1633
/FEREYDOUN G SAJJADI/Supervisory Patent Examiner, Art Unit 1699
Prosecution Insights