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 .
Applicant’s amendment filed on 2/18/2025 is acknowledged.
Claims 21-35 are pending.
Election/Restrictions
Applicant’s election without traverse of Invention Group I drawn to a method of generating hypoimmunogenic hepatocytes or progenitors thereof in the reply filed on 4/9/2026 is acknowledged.
Claims 26-35 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on 4/9/2026.
Applicant’s election without traverse of the species of CRISPR/Cas9 gene editing composition and conditions sufficient to generate an HLA-class I deficiency, primary human hepatocytes (HPP) cell population, pig in vivo bioreactor and conditions sufficient to produce an expanded population of hypoimmunogenic hepatocytes in the reply filed on 4/9/2026 is acknowledged.
As such claims 21-25 are under consideration as they read on the elected Invention Group I and species election of CRISPR/Cas9 gene editing composition and conditions sufficient to generate an HLA-class I deficiency, primary human hepatocytes (HPP) cell population, pig in vivo bioreactor and conditions sufficient to produce an expanded population of hypoimmunogenic hepatocytes.
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Written Description
Claims 21-25 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
Applicant is in possession of: a method of generating HLA class I deficient hepatocytes or progenitors thereof, the method comprising: contacting a cell population comprising human hepatocytes or progenitors thereof with a beta-2-microglobulin (B2M) knockout CRISPR/Cas9 editing system of instant claims 21-22; the method further comprising introducing the generated population of HLA class I deficient hepatocytes or progenitors thereof into a pig in vivo bioreactor to produce an expanded population of HLA class I deficient hepatocytes.
Applicant is not in possession of: a method of generating hypoimmunogenic hepatocytes or progenitors thereof, the method comprising: contacting a cell population comprising human hepatocytes or progenitors thereof with an editing composition under conditions sufficient to generate a HLA class I deficiency in the hepatocytes or progenitors thereof , thereby generating a population of hypoimmunogenic hepatocytes or progenitors thereof of instant claim 21; wherein the editing composition is a beta-2-microglobulin (B2M)-editing composition of instant claim 22; the method further comprising introducing the generated population of hypoimmunogenic hepatocytes or progenitors thereof into an in vivo bioreactor maintained under conditions sufficient to produce an expanded population of hypoimmunogenic hepatocytes of instant claim 23; and the in vivo bioreactors of instant claims 24-25.
The claims encompass methods comprising a broad genus of editing compositions under broad conditions sufficient to generate a HLA class I deficiency in hepatocytes or progenitors thereof and a broad genus of hypoimmunogenic hepatocytes or progenitors thereof. The recitation of a B2M-editing composition in instant claim 22 encompasses a broad genus of B2M-editing compositions.
Regarding editing compositions, the specification ([0140]; [0145]-[1053]) discloses numerous editing compositions which are based on the editing-system employed, the type of edit desired, the sequence of the targeted locus or loci, etc. which can include CRISPR/Cas9, TALEN, ZFN, base-editing editing compositions, and the like. The specification ([0146; [0148]; Examples 1-2) discloses a useful embodiment to be a CRISPR Cas9-based B2M targeting sequences and corresponding PAM sequences which can render the edited hepatocyte or progenitor thereof hypoimmunogenic. The specification ([0149]) discloses the editing compositions may be contacted with a cell population under conditions sufficient to generate the desired edit including but not limited to suitable culture conditions, including e.g., maintenance at a suitable environmental condition (e.g., temperature, gas exchange, etc.) in a suitable culture medium conducive to the editing reaction, and the like. However, there is no further discussion of other types of editing compositions and lacks other working examples showing the different types of editing compositions and conditions sufficient to generate a HLA class I deficiency.
The specification does not reasonably convey possession of the full scope of editing compositions and B2M-editing compositions to generate a population of hypoimmunogenic hepatocytes or progenitors thereof encompassed by the claims. Absent a limiting species for “editing compositions” and “B2M-editing compositions”, the genus opens up the claimed invention to all editing compositions including gene and non-gene (RNA and protein) editing compositions and editing compositions that directly or indirectly edit the human hepatocytes or progenitors thereof under conditions sufficient to generate a HLA class I deficiency in the hepatocytes or progenitors thereof including small molecule inhibitors and antibodies targeting HLA class I genes and antisense oligonucleotides (ASOs) and small interfering RNAs (siRNAs) to reduce B2M expression at the mRNA level.
The art of Joo et al (PTO-892; Reference U; “Joo”) teaches that editing compositions can include gene editing compositions such as CRISPR-Cas9, TALENs, ZFNs, meganucleases, base editing, prime editing as well as epigenome editing and RNA editing that do not induce double strand DNA breaks each with their own mechanisms of action (Joo; whole document). The art of PatSnap (PTO-892; Reference V) teaches B2M inhibitors are designed to reduce or block the activity of B2M where a primary approach involves small molecule inhibitors that bind B2M directly leading to its destabilization and degradation (PatSnap; paragraph 3). B2M monoclonal antibodies can also neutralize B2M by binding it, preventing it from interacting with MHC class I molecules and other cellular receptors (PatSnap; paragraph 3). Other approaches include ASOs and siRNAs to reduce B2M expression at the mRNA level and subsequently the protein level (PatSnap; paragraph 4).
The claims encompass a broad genus of in vivo bioreactors maintained under broad conditions sufficient to produce an expanded population of hypoimmunogenic hepatocytes. The skilled artisan cannot envision all of the in vivo bioreactors under many different conditions that are considered sufficient to produce an expanded population of hypoimmunogenic hepatocytes recited in the instant claims.
The specification (page 11, [046]) describes the term in vivo bioreactor to refer to a living non-human animal into which exogenous cells, such as hepatocyte generating cells, are introduced for engraftment and expansion which can involve xenotransplantation e.g., human-to-rodent xenograft, human-to-mouse xenograft, human-to-rat xenograft, human-to-porcine xenograft, mouse-to-rat xenograft, rat-to-mouse xenograft, rodent-to-porcine xenograft, etc. or allotransplantation, rodent-to-rodent, porcine-to-porcine, etc.. Examples 3-4 describes the transplantation and expansion of B2M KO primary human hepatocytes into recipient FRGN rodents (mice and rat). However, there are no other working examples of other non-human animals that can perform the function of an “in vivo bioreactor” and conditions sufficient to produce an expanded population of hypoimmunogenic hepatocytes.
The specification does not reasonably convey possession of the full scope of in vivo bioreactors encompassed by the claims. Absent a limiting species for “in vivo bioreactors”, the genus opens up the claimed invention to all in vivo bioreactors including any non-human animal and any method of expanding a cell population in a non-human animal model.
The art of Sanal (PTO-892; Reference W; “Sanal”) teaches pigs are the preferred animal for humanized organs, although primates like chimpanzees or gibbons would be ideal for the generation of “humanized” organs and that the engineered animals need to lack certain antigens so that organs can be used for transplantation in human patients to reduce the chance of immune rejection (Sanal; page 3685, “Humanized Liver in Animals”). Sanal teaches a wide variety of non-human animals that can be used as animal models to grow human cells including mice, rats, sheep, non-human primates, etc. (Sanal; page 3686, right column). Sanal teaches non-human primates the preferred animal model since they share 98% genetic homology to humans and that the physiology of non-human primates including body temperature, general blood biochemistry, red blood cell count, white cell count, platelet count, osmolarity, plasma protein concentration, etc. falls within the range of human values (Sanal; page 3687, left column, paragraph 2). These conditions are important to support the growth of the implanted cell and/or organ.
As such, claims 21-25 do not meet the requirements of 35 U.S.C. 112(a) for written description as they are currently written.
Enablement
Claims 21-25 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the enablement requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to enable one skilled in the art to which it pertains, or with which it is most nearly connected, to make and/or use the invention.
While being enabled for: a method of generating HLA class I deficient hepatocytes or progenitors thereof, the method comprising: contacting a cell population comprising human hepatocytes or progenitors thereof with a beta-2-microglobulin (B2M) knockout CRISPR/Cas9 editing system of instant claims 21-22; the method further comprising introducing the generated population of HLA class I deficient hepatocytes or progenitors thereof into a pig in vivo bioreactor to produce an expanded population of HLA class I deficient hepatocytes;
The specification does not reasonably provide enablement for: a method of generating hypoimmunogenic hepatocytes or progenitors thereof, the method comprising: contacting a cell population comprising human hepatocytes or progenitors thereof with an editing composition under conditions sufficient to generate a HLA class I deficiency in the hepatocytes or progenitors thereof , thereby generating a population of hypoimmunogenic hepatocytes or progenitors thereof of instant claim 21; wherein the editing composition is a beta-2-microglobulin (B2M)-editing composition of instant claim 22; the method further comprising introducing the generated population of hypoimmunogenic hepatocytes or progenitors thereof into an in vivo bioreactor maintained under conditions sufficient to produce an expanded population of hypoimmunogenic hepatocytes of instant claim 23; and the in vivo bioreactors of instant claims 24-25.
Factors to be considered in determining whether undue experimentation is required to practice the claimed invention are summarized In re Wands (858 F2d 731, 737, 8 USPQ2d 1400, 1404 (Fed. Cir. 1988)). The factors most relevant to this rejection are the scope of the claim, the amount of direction or guidance provided, the lack of sufficient working examples, the unpredictability in the art and the amount of experimentation required to enable one of skill in the art to practice the claimed invention.
The specification does not enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to use the invention commensurate in scope with these claims. The specification disclosure does not enable one skilled in the art to practice the invention without undue amount of experimentation.
The breadth of claims 21-25 encompass all editing compositions and any condition(s) sufficient to generate a HLA class I deficiency in hepatocytes of progenitors thereof. Editing compositions have different mechanisms of action and have require different reagents and conditions to produce the intended editing result.
The specification ([0140]; [0145]-[1053]) discloses numerous editing compositions which are based on the editing-system employed, the type of edit desired, the sequence of the targeted locus or loci, etc. which can include CRISPR/Cas9, TALEN, ZFN, base-editing editing compositions, and the like. The specification ([0146; [0148]; Examples 1-2) discloses a useful embodiment to be a CRISPR Cas9-based B2M targeting sequences and corresponding PAM sequences which can render the edited hepatocyte or progenitor thereof hypoimmunogenic. The specification ([0149]) discloses the editing compositions may be contacted with a cell population under conditions sufficient to generate the desired edit including but not limited to suitable culture conditions, including e.g., maintenance at a suitable environmental condition (e.g., temperature, gas exchange, etc.) in a suitable culture medium conducive to the editing reaction, and the like. However, there is no further discussion of other types of editing compositions and lacks other working examples showing the different types of editing compositions and conditions sufficient to generate a HLA class I deficiency.
It is well established in the art according to Joo et al (PTO-892; Reference U; “Joo”) that each type of gene editing composition has its own mechanism of action requiring different reagents and conditions sufficient to perform the gene edit (Joo; whole document). Additionally, Joo teaches the ZFN, TALENs, and CRISPR gene editing compositions require custom DNA-binding proteins for each genomic target (Joo; page 3, left column, paragraph 3).
The prior art does not appear to provide any evidence as to the treatment of the full scope of the claims of any as such, not any editing composition can under any conditions can generate a HLA class I deficiency in hepatocytes or progenitors thereof without undue experimentation.
The breadth of claims 23-25 encompass all in vivo bioreactors and any condition(s) sufficient to produce an expanded population of hypoimmunogenic hepatocytes. In vivo bioreactors have different physiological features and require different conditions in order to grow the injected cells or organ graft.
The specification (page 11, [046]) describes the term in vivo bioreactor to refer to a living non-human animal into which exogenous cells, such as hepatocyte generating cells, are introduced for engraftment and expansion which can involve xenotransplantation e.g., human-to-rodent xenograft, human-to-mouse xenograft, human-to-rat xenograft, human-to-porcine xenograft, mouse-to-rat xenograft, rat-to-mouse xenograft, rodent-to-porcine xenograft, etc. or allotransplantation, rodent-to-rodent, porcine-to-porcine, etc.. Examples 3-4 describes the transplantation and expansion of B2M KO primary human hepatocytes into recipient FRGN rodents (mice and rat). However, there are no other working examples of other non-human animals that can perform the function of an “in vivo bioreactor” and conditions sufficient to to produce an expanded population of hypoimmunogenic hepatocytes.
The art of Sanal et al (Sanal; PTO-892; Reference W; “Sanal”) teaches that the animal model needs to be specifically selected since there is a possibility of host immune rejection and incompatibility in growth factors, transcription factors, and/or signaling pathways or else it becomes unpredictable if the injected and/or implanted cells will thrive and proliferate (Sanal; page 3687). Sanal does teach that immunological rejection is less likely to be a major problem in the liver since the liver is immune tolerant, the patients own cells will be used to generate a new liver with 100% HLA matching, and there are better, less toxic immunosuppressants available for use (Sanal; page 3688, left column, paragraph 1). Sanal teaches pigs are the preferred animal for humanized organs, but non-human primates would be more ideal since they share 98% genetic homology with humans and have similar physiological environments supporting cell and/or organ growth and development. Other animals such as mice, rats, sheep, etc. can also be used as in vivo bioreactors (Sanal; page 3686-3687).
However, the prior art establishes that it becomes unpredictable if all animals can perform the function of an “in vivo bioreactor” and support the growth and expansion of the engrafted cell population efficiently and effectively since pigs and non-human primates are the preferred and ideal animal models. The prior art does not appear to provide any evidence as to the treatment of the full scope of the claims of any as such, not any in vivo bioreactor maintained under any conditions can produce an expanded population of hypoimmunogenic hepatocytes without undue experimentation.
In view of the quantity of experimentation necessary, the lack of working examples, the unpredictability in the art, the lack of sufficient guidance in the specification, and the breadth of the claims, it would take undue trials and errors to make and use the encompassed editing compositions under sufficient conditions to generate a HLA class I deficiency in hepatocytes, B2M-editing compositions, in vivo bioreactors maintained under conditions sufficient to expand a population of hypoimmunogenic hepatocytes.
Reasonable correlation must exist between the scope of the claims and scope of the enablement set forth. In view of experimentation necessary the limited working examples, the nature of the invention, the state of the prior art, the unpredictability of the art and the breadth of the claims, it would take undue trials and errors to practice the claimed invention.
Priority
This application is a 371 of PCT/US2022/013718 effectively filed on 1/25/2022 and claims domestic priority to U.S. Provisional Application 63/141,769 effectively filed on 1/26/2021.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 21 and 22 are rejected under 35 U.S.C. 102 (a)(1) as being anticipated by Ye et al (IDS filed on 2/18/2025, NPL Reference 2; "Ye").
Ye teaches that stem cels are a valuable source for regenerative medicine through cell therapy as hPSCs and iPSCs can differentiate into any type of cell in the human body; however, there is an immunological barrier to the clinical usage of hPSCs that restrict the transplantation of allogenic cells that originate from HLA cell surface presentation (Ye; page 1, Introduction, page 2, left column). To address this barrier, Ye teaches the development of hPSCs that do not express HLA class I and II molecules even after differentiation into specific cell lineages (Ye; page 3, left column). Ye specifically teaches using CRISPR/Cas9 gene editing system as a safe substitute to lentiviral based gene editing systems to knockout beta-2-microglobulin (B2M) in hPSCs to create hypoimmunogenic hPSCs (Ye; page 5, right column, paragraphs 3-5; page 9, right column, paragraph 3).
Regarding claim 21, Ye teaches a method of generating hypoimmunogenic hepatocytes or progenitors thereof, the method comprising: contacting a cell population comprising human hepatocytes or progenitors thereof with an editing composition under conditions sufficient to generate a human leukocyte antigen (HLA) class I deficiency in the hepatocytes or progenitors thereof, thereby generating a population of hypoimmunogenic hepatocytes or progenitors thereof (Ye; Abstract; Figure 1-2; Section 2.1).
Regarding claim 22, Ye teaches wherein the editing composition is a beta-2-microglobulin (B2M)-editing composition (Ye; Abstract; Figure 1-2; Section 2.1).
The reference teachings anticipate the claimed invention.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1 and 23-25 are rejected under 35 U.S.C. 103 as being unpatentable over Ye et al (IDS filed on 2/18/2025, NPL Reference 2; "Ye") in view of JP 2011223976 A (PTO-892; Reference N; "Grompe").
Ye teaches that stem cells are a valuable source for regenerative medicine through cell therapy as hPSCs and iPSCs can differentiate into any type of cell in the human body; however, there is an immunological barrier to the clinical usage of hPSCs that restrict the transplantation of allogenic cells that originate from HLA cell surface presentation (Ye; page 1, Introduction, page 2, left column). To address this barrier, Ye teaches the method of developing hPSCs that do not express HLA class I and II molecules even after differentiation into specific cell lineages (Ye; page 3, left column). Ye specifically teaches using CRISPR/Cas9 gene editing system as a safe substitute to lentiviral based gene editing systems to knockout beta-2-microglobulin (B2M) in hPSCs to create hypoimmunogenic hPSCs which can then be differentiated into human hepatocytes (Ye; page 5, right column, paragraphs 3-5; page 9, right column, paragraph 3).
However, Ye does not teach the method of claim 21 further comprising introducing the generated population of hypoimmunogenic hepatocytes or progenitors thereof into an in vivo bioreactor maintained under conditions sufficient to produce an expanded population of hypoimmunogenic hepatocytes of instant claim 23; wherein the in vivo bioreactor is a pig of instant claims 24-25.
Grompe does teach that bioartificial liver assist devices that use hepatocytes ex vivo have been used to assist patients with acute liver failure and several clinical trials have provided a proof of principle that hepatocyte transplantation may be beneficial; however, human hepatocytes cannot be proliferated significantly in culture (Grompe; Abstract; [0004]). Grompe teaches that a method for expanding primary human hepatocytes is highly desirable so that sufficient human hepatocytes become available to allow bioartificial liver assist devices to become practical technology and to expand the application of human hepatocyte transplantation (Grompe; [0004]). Therefore, Grompe teaches methods for growing primary human hepatocytes in vivo including transplanting human hepatocytes into a Fah-deficient pig and expanding the human hepatocytes (Grompe; Abstract; Fig. 1; [0016]; [0092]; [0101]; [0124]).
It would have been prima facie obvious to a person of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the method of developing hypoimmunogenic B2M knockout hPSCs of Ye with the method of expanding human primary hepatocytes in vivo of Grompe with reasonable expectation of success. One of ordinary skill in the art would have been motivated to have combined the method of developing hypoimmunogenic B2M knockout hPSCs of Ye with the method of expanding human primary hepatocytes in vivo of Grompe since Grompe teaches that there are significant challenges in human hepatocyte proliferation in vitro and that expanding human hepatocytes in an in vivo pig model can induce increased proliferation and expansion of the transplanted human hepatocytes. Therefore, a person of ordinary skill in the art would have been motivated to combine the method of developing hypoimmunogenic B2M knockout hPSCs of Ye with the method of expanding human primary hepatocytes in vivo of Grompe to yield predictable results of increased expansion and proliferation of the transplanted cell population.
From the combined teachings of the reference, it is apparent that one of ordinary skill in the art would have had a reasonable expectation of success in producing the claimed invention. Therefore, the invention as a whole was prima facie obvious to one of ordinary skill in the art at the time the invention was made, as evidenced by the reference, especially in the absence of evidence to the contrary.
No claim is allowed.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to LEAH ELIZABETH STEIN whose telephone number is (571)272-0093. The examiner can normally be reached M-F 8-5:30 EST.
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/LEAH ELIZABETH STEIN/ Examiner, Art Unit 1641
/NORA M ROONEY/ Primary Examiner, Art Unit 1641
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