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
This action is in response to the papers filed December 16, 2025.
Claim Amendments
Applicant’s amendment to the claims filed 12/16/2025 is acknowledged.
Claims 8-16, 19-27, and 37 have been cancelled.
Claims 1-7, 17-18, 28-36 are pending and under examination.
Election/Restrictions
Applicant’s reply filed 12/16/2025 to the Requirement for Restriction/Election mailed 09/17/2025 is acknowledged.
Applicant elected without traverse the invention of Group 1, drawn to a method of producing megakaryocytes and/or platelets.
Priority
The instant application 18/248,193 was filed on 04/06/2023. This application is a national stage of international application PCT/US2021/071903 filed 10/15/2021, claiming priority based on U.S. Provisional Application No. 63/092,024 filed 10/15/2020.
Information Disclosure Statement
The information disclosure statements (IDS) submitted on 11/22/2023 and 02/27/2025 have been considered.
The listing of references in the specification is not a proper information disclosure statement. 37 CFR 1.98(b) requires a list of all patents, publications, or other information submitted for consideration by the Office, and MPEP § 609.04(a) states, "the list may not be incorporated into the specification but must be submitted in a separate paper." Therefore, unless the references have been cited by the examiner on form PTO-892, or by applicant in an information disclosure statement (IDS), they have not been considered.
Claim Objections
Claims 18, 29 and 31 are objected to because of the following informalities:
In claim 18, the term “IL-1B” should be “IL-1β” instead.
In claim 29, the phrase “GDP fucose” should be “guanosine diphosphate (GDP) fucose” instead.
In claim 31, the term “B2M” (occurring twice in line 8) should be “β2M” instead.
Appropriate action is required.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1-7, 17-18, 28-30, and 36 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 1 recites that the CD34+ cells comprise “knock-in of HLA class I histocompatibility antigen, alpha chain E (HLA-E), at the genomic locus of β2-microglobulin (β2M), thereby reducing or eliminating expression of the HLA class I gene product in the CD34+ cells.” The recitation is indefinite for the following reasons:
Based on the claim construction, “the HLA class I gene product” would appear to refer to “HLA class I histocompatibility antigen, alpha chain E (HLA-E)” because the phrase “HLA class I” does not appear elsewhere in the claim. Therefore, it is inconsistent to claim that the HLA class I gene product, or HLA-E, has been knocked-in and therefore disrupted. To the extent that one of ordinary skill in the art would have recognized β2-microglobulin (β2M) as an HLA class I gene product, then the limitation “the HLA class I gene product” lacks sufficient antecedent basis because the claim previously recites at least two HLA class I gene products: HLA-E and β2M.
For these reasons, one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. Dependent claims 2-7, 17-18, 28-30, and 36 are included in the basis of the rejection because they do not correct the deficiencies of the claim upon which they depend.
Amending the phrase “the HLA class I gene product” to “the β2M gene product” would be remedial.
Claims 28-29 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 28 recites a step of subject MSCs, the CD34+ cells, and/or megakaryocytes to “an effective amount of one or more means of fucosylation” of the CD34+ cells, MSCs, and/or megakaryocytes. The recitation is indefinite because “means of fucosylation” refers to a means or process of fucosylation and not an agent or composition that causes fucosylation. Therefore, there is no “effective amount” of a means or process of fucosylation.
For these reasons, one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. Dependent claim 29 is included in the basis of the rejection because it does not correct the deficiencies of the claim upon which it depends.
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.
Claims 2, 17, and 36 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.
Claim 2 recites a “step of enhancing production of platelets from the megakaryocytes,” and therefore broadly embraces any means or process that would enhance the production of platelets from megakaryocytes. Accordingly, claim 2 is directed to a broad, structurally-undisclosed genus of process steps that is functionally-defined as enhancing the production of platelets from the megakaryocytes.
An adequate written description of a genus of process steps which enhance platelet production requires more than a mere statement that it is part of the invention. What is required is either (1) a description of a common core structure shared among the members (species) of the functionally-described genus or (2) a disclosure of a representative number of species of the functionally-described genus. It is not sufficient to define a genus of process steps solely by its desired biological property, i.e., enhancing platelet production, because disclosure of no more than that, as in the instant case, is simply a wish to know the identity of any means that is capable of doing so. Thus, claiming all process steps that enhance platelet production, without defining what means will do, or without disclosing a representative number of species, is not in compliance with the written description requirement.
The specification as filed does not appear to describe a single, particular process step what enhances platelet production, at least not beyond those limitations already recited by claim 1. Therefore, the specification as filed is not found to describe a representative number of process steps for the claimed genus.
Accordingly, this limited information is not deemed sufficient to reasonably convey to one skilled in the art that the applicant is in possession of the broad genus of process steps that enhance platelet production at the time the application was filed. Amending the phrase “step of enhancing production of platelets” to “step of producing platelets” would be remedial.
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.
Claims 1-7, 17, 31-32, 34-36 are rejected under 35 U.S.C. 103 as being unpatentable over US 2012/0238020 A1 to Mitchell et al.; in view of US 9,993,503 B2 to Feng et al. (issued: 12-Jun-2018); and US 2020/0080114 A1 to Rezania, Alireza (published: 12-Mar-2020).
Mitchell discloses methods of obtaining populations of megakaryocytes and platelets by ex vivo culture of stem cells. Abstract.
The method comprises co-culturing mesenchymal stem cells (MSCs) with CD34+ hematopoietic stem cells in one or more vessels with a media composition comprising an effective amount of stem cell factor (SCF), thrombopoietin (TPO) and interleukin-6 (IL-6), under conditions to produce megakaryocytes. Paragraphs 36-38, 56-57, 62-64, 66-67, 77, 82; Figures 1, 6; claims 1-2, 4-7, 10.
Mitchell does not teach or fairly suggest that the CD34+ cells have been manipulated to comprise a knock-in of HLA class I histocompatibility antigen, alpha chain E (HLA-E), at the genomic locus of β2-microglobulin (β2M).
Feng is relevant prior art for teaching methods of producing platelets from megakaryocytes, wherein the megakaryocytes are derived from stem cells (Abstract; col. 3, ll. 45-61). The megakaryocytes or megakaryocyte lineage-specific progenitor cells (MLPs) may be derived from induced pluripotent stem cells, embryonic stem cells, or naturally-occurring CD34+ cells (col. 12, ll. 43-45). The cell culture media comprises TPO, SCF and IL-6 (col. 3, ll. 52-61; col. 4, ll. 28-21). Feng further teaches knocking-out the β2-microglobulin (β2M) gene to generate platelets that are HLA-ABC negative (col. 65, ll. 11-17).
In addition, Rezania is relevant prior art for teaching methods of generating “universal donor cells” that are compatible with any HLA genotype, less susceptible to allogeneic rejection, and/or possess increased survival after transplantation relative to an unmodified cell (Abstract; par. 5, 65). The universal donor cell may be a hematopoietic stem or progenitor cell (HSPC) or a differentiated cell, such as megakaryocytes and platelets (par. 13, 65, 163, 167). The methods of generating universal donor cells comprises genetically-modifying a pluripotent stem cell (PSC) or HSPC by introducing a nucleic acid encoding a tolerogenic factor at the β2M genomic locus, wherein the tolerogenic factor is HLA-E (par. 8, 19, 13, 148).
Therefore, prior to the effective filing date of the instantly claimed invention, it would have been prima facie obvious to one of ordinary skill in the art to modify the method of Mitchell by manipulating the CD34+ cells to comprise knock-in of a nucleic acid encoding HLA-E at the β2M genomic locus, in view of Feng and Rezania, with a reasonable expectation of success because such a modification would generate HSPCs/megakaryocytes/platelets that are HLA-ABC negative and overexpress the tolerogenic factor HLA-E, thereby producing universal donor cells that are less susceptible to allogeneic rejection and/or possess increased survival after transplantation relative to an unmodified cell.
For these reasons, the invention as claimed in claim 1 would have been prima facie obvious over the prior art.
Claim 31 further recites a step of subjecting the megakaryocytes to suitable conditions to produce an effective amount of platelets. This step is also taught by Mitchell (par. 59, 62, 70; fig. 6; claim 1) and Feng (col. 3, ll. 45-61). For these reasons, and those provided above, the invention as claimed in claim 31 would have been prima facie obvious over the prior art.
Regarding dependent claim 2, a step of enhancing production of platelets from the megakaryocytes is taught by Mitchell (par. 59, 62, 70; fig. 6; claim 1) and Feng (col. 3, ll. 45-61).
Regarding dependent claim 3, Mitchell teaches that the CD34+ hematopoietic stem cells are derived from bone marrow or umbilical cord blood (UBC; par. 77), and the mesenchymal stem cells may also be derived from umbilical cord blood (par. 82). Feng teaches that the naturally-occurring CD34+ cells are derived from bone marrow or umbilical cord blood (col. 12, 43-45)
Regarding dependent claims 4 and 32, Mitchell teaches the one or more vessels further comprise an effective amount of a ROCK inhibitor (par. 38, 41, 51, 57, 70). Feng teaches that the media composition comprises a ROCK inhibitor (col. 4, ll. 18-24; col. 9, ll. 1-61).
Regarding dependent claim 5, Mitchell teaches the ROCK inhibitor is Y27632, GSK429286a, or fasudil HCl (par. 41). Feng teaches that the ROCK inhibitor is Y27632 (col. 4, ll. 18-24; col. 9, ll. 1-61).
Regarding dependent claim 6, Mitchell teaches ROCK inhibitors that inhibit ROCK1 and/or ROCK2 (par. 41). Feng teaches ROCK inhibitors that inhibit ROCK1 and/or ROCK2 (col. 4, ll. 18-24; col. 9, ll. 1-61).
Regarding dependent claim 7, Mitchell does not expressly disclose that the media composition contains serum (see, e.g., par. 37-38, 63, 66, 79; claims 5-7). Feng teaches that the media composition lacks serum (col. 2, ll. 51-63; col. 16, ll. 31-33; col. 17, ll. 16-25).
Regarding dependent claim 17, Feng discloses that the megakaryocytes are reused to produce additional platelets. See steps 16-18 in Figure 14C, D.
Regarding dependent claims 34-36, Mitchell teaches providing an effective amount of the platelets to a subject in need thereof, such as a subject having thrombocytopenia, platelet defects, or bleeding conditions (par. 73). Feng teaches providing an effective amount of the platelets to a subject in need thereof (col. 37, ll. 45, to col. 38, ll. 14), wherein the subject has thrombocytopenia, trauma, or cancer (col. 5, ll. 6-33; col. 34, ll. 61-64)
Claim 18 is rejected under 35 U.S.C. 103 as being unpatentable over US 2012/0238020 A1 to Mitchell et al.; US 9,993,503 B2 to Feng et al. (issued: 12-Jun-2018); and US 2020/0080114 A1 to Rezania, Alireza (published: 12-Mar-2020), as applied to claims 1-7, 17, 31-32, 34-36 above; in further view of US 2005/0086710 A1 to Peluso et al.
Regarding dependent claim 18, Mitchell, Feng and Rezania do not teach or fairly suggest the media comprises an effective amount of IL-1β.
Peluso is relevant prior art for discloses a method of preparing platelets, comprising providing hematopoietic progenitor cells, generating megakaryocytes from the hematopoietic progenitor cells, inducing shedding of platelets from the megakaryocytes, and isolating the platelets form the cell culture. Paragraphs 59-66. Peluso teaches that a cytokine cocktail comprising thrombopoietin (TPO), stem cell factor (SCF), interleukin-6 (IL-6) and interleukin-1β (IL-1β) increased generation of platelets relative to other cytokine cocktails tested. Paragraphs 70, 79, 109-110; Figure 1.
Therefore, prior to the effective filing date of the instantly claimed invention, it would have been prima facie obvious to one of ordinary skill in the art to modify the method of Mitchell such that the media further comprises an effective amount of IL-1β, in view of Peluso, with a reasonable expectation of success because the combination of TPO, SCF, IL-6 and IL-1β results in improved generation of platelets from megakaryocytes.
Claims 28-30 are rejected under 35 U.S.C. 103 as being unpatentable over US 2012/0238020 A1 to Mitchell et al.; US 9,993,503 B2 to Feng et al. (issued: 12-Jun-2018); and US 2020/0080114 A1 to Rezania, Alireza (published: 12-Mar-2020), as applied to claims 1-7, 17, 31-32, 34-36 above; in further view of Popat et al. (2015) “Enforced fucosylation of cord blood hematopoietic cells accelerates neutrophil and platelet engraftment after transplantation” Blood, The Journal of the American Society of Hematology, 125(19), 2885-2892.
Regarding dependent claims 28-30, Mitchell, Feng and Rezania do not teach or fairly suggest that the MSCs, CD34+ cells and/or megakaryocytes are subject to a means of fucosylation.
Popat is relevant prior art for teaching that ex vivo fucosylation of cord-blood (CB) cells improves their homing capacities, leading to faster neutrophil and platelet engraftments. The means of fucosylation included ex vivo incubation of CB cells with the enzyme fucosyltransferase-VI (FT-VI) and guanosine diphosphate (GDP) β-fucose. Abstract; Key Points on pg. 2885; Figure 1.
Popat further teaches that CB cell expansion by co-culture with mesenchymal stromal cells also results in improved neutrophil and platelet engraftment, and therefore ex vivo fucosylation of such expanded CB cells may further accelerate engraftment. Page 2891, right column.
Therefore, prior to the effective filing date of the instantly claimed invention, it would have been prima facie obvious to one of ordinary skill in the art to modify the method of Mitchell to further comprise ex vivo fucosylation of the CD34+ cells by culturing in the presence of a fucosyl-transferase enzyme and a GDP fucose substrate, in view of Popat, with a reasonable expectation of success because ex vivo fucosylation improves platelet engraftment.
For these reasons, dependent claims 28-30 would have been prima facie obvious over the prior art.
Claim 33 is rejected under 35 U.S.C. 103 as being unpatentable over US 2012/0238020 A1 to Mitchell et al.; US 9,993,503 B2 to Feng et al. (issued: 12-Jun-2018); and US 2020/0080114 A1 to Rezania, Alireza (published: 12-Mar-2020), as applied to claims 1-7, 17, 31-32, 34-36 above; in further view of Sullenbarger et al. (2009) “Prolonged continuous in vitro human platelet production using three-dimensional scaffolds” Experimental hematology, 37:101-110.
Regarding dependent claim 33, the claim recites that the CD34+ cells are cultured in the same vessel or substrate that the megakaryocytes produce the platelets.
Prior to the effective filing date of the instantly claimed invention, Sullenbarger discloses a 3D bioreactor system, wherein that the CD34+ cells are cultured and the megakaryocytes produce the platelets in the same vessel or substrate. The medium used to promote megakaryocyte and platelet production contained TPO, SCF and IL-6. Use of the bioreactor system produced greater daily numbers for platelet production relative to the other systems tested. See, e.g., Abstract; pg. 104; fig. 1A, B.
Therefore, it would have been prima facie obvious to one of ordinary skill in the art to modify the method of Mitchell such that that the CD34+ cells are cultured in the same vessel or substrate that the megakaryocytes produce the platelets, in view of Sullenbarger, with a reasonable expectation of success because Sullenbarger shows that a bioreactor system, wherein the CD34+ cells are cultured in the same vessel or substrate that the megakaryocytes produce the platelets, produced greater numbers of platelets daily relative to other systems.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure:
De Lima et al. (2012) “Cord-blood engraftment with ex vivo mesenchymal-cell coculture” New England Journal of Medicine, 367(24), 2305-2315, discloses the ex vivo expansion of CD34+ cord-blood cells with mesenchymal stem cells (MSCs), and transplantation thereof into adults with hematologic cancers. See, e.g., Abstract. MSCs naturally sescrete cytokines that influence hematopoiesis, including stem cell factor (SCF), interleukin-6 (IL-6) and thrombopoietin (TPO). See, Supplementary Material, Protocol, pg. 5-7.
Gornalusse et al. (2017) “HLA-E-expressing pluripotent stem cells escape allogeneic responses and lysis by NK cells” Nature biotechnology, 35(8), 765-772, discloses adeno-associated virus (AAV)-mediated gene editing to knock-in HLA-E genes at the beta-2-microglobulin (B2M) genomic locus in human pluripotent stem cells (PSCs). The engineered PSCs and their differentiated derivatives are not recognized as allogeneic by CD8+ T cells, do not bind to anti-HLA antibodies and are resistant to natural kill (NK) cell-mediated lysis, thus providing “universal donor cells.” See, e.g., Abstract.
US 7,776,591 B2 to Xia et al. (issued: 17-Aug-2010) discloses a method of in vitro fucosylation of selectin ligands on cord blood-derived hematopoietic stem cells (Abstract).
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/JAMES JOSEPH GRABER/Examiner, Art Unit 1631