DETAILED ACTION
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 .
Status of the Claims
Claims 1-4, 6, 8, 11-13, and 21-26 are pending (claim set as filed on 02/20/2026).
Election/Restrictions
Applicant’s election with traverse of Group II, drawn to composition claims, filed on 08/25/2024 is again acknowledged.
Method claims 1-4, 6, and 8 stand withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a non-elected invention, there being no allowable generic or linking claim. However, newly added method claims 23-25 are directed to an invention(s) that is independent, distinct, and/or lacks a special technical feature for the reasons reprised from the Restriction Requirement mailed on 06/26/2024. Therefore, new claims 23-25 are withdrawn from consideration as being directed to a method of making similar to claims 1-4, 6, and 8.
Accordingly, only composition claims 11-13, 21-22, and 26 are under examination.
Priority
This application is a 371 of PCT/US2020/023459 filed on 03/18/2020, which has a PRO application no. 62/820,367 filed on 03/19/2019.
Maintained Rejections
Claim Rejections - 35 USC §103, Obviousness
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 11-13 and 21-22 are rejected under 35 U.S.C. 103 as being unpatentable over O’Connor (US 2013/0273570 A1 - newly cited) in view of Desiderio (Human Ng2R Adipose Stem Cells Loaded In Vivo on a New Crosslinked Hyaluronic Acid-Lys Scaffold Fabricate a Skeletal Muscle Tissue, 2013) and Madsen (Decoy TRAIL receptor CD264: a cell surface marker of cellular aging for human bone marrow-derived mesenchymal stem cells, 2017) - secondary references in the IDS filed on 02/01/2022.
O’Connor’s general disclosure relates to identification and isolation of mesenchymal stem cells (MSCs) that are multipotent and highly efficient in colony formation using immunophenotyping (see ¶ [0003]-[0007]).
O’Connor teaches “a method of identifying multipotent MSCs capable of high proliferation … Antibodies targeting CD146 and NG2 antigens conjugated with indicators are exposed to collection of heterogeneous stem cells. The attachment of these antibodies on the surface of stem cells indicates the presence of CD146 and/or NG2 antigens. The MSCs with the high expression of CD146, NG2 or a combination of both can be selected using flow cytometry or other selection techniques” (see ¶ [0008]-[0010]). O’Connor discloses “NG2 refers to nerve/glial antigen 2, and is an antigen expressed on the surface of some stem cells. NG2 antibody refers to any antibody that binds to the NG2 antigen. This invention discloses the association between NG2 expression and stem cell differentiation potential” (see ¶ [0021]-[0023]). O’Connor teaches “Using this invention makes it possible to exploit differential growth kinetics to enrich multipotent cells in a heterogeneous MSC preparation during ex vivo amplification for clinical use by using the markers NG2 and CD146. The ease of identification of MSCs with multipotency and efficient colony formation, and further culturing of the isolated MSCs with high expression of CD146 and NG2, can provide a source of MSCs for therapy and research” (see ¶ [0055]).
However, O’Connor does not teach: a scaffold (claim 11’s limitation and claim 12); or wherein less than 30% or 10% of the MSCs are CD264+ (claim 11’s limitation and claim 13); or at least 70% are CD264+ (claims 21-22).
Desiderio teaches “mesenchymal stem cell (MSC) therapy holds promise for treating diseases and tissue repair. Regeneration of skeletal muscle tissue that is lost during pathological muscle degeneration or after injuries is sustained by the production of new myofibers. Human adipose stem cells (ASCs) have been reported to regenerate muscle fibers and reconstitute the pericytic cell pool after myogenic differentiation in vitro. Our aim was to evaluate the differentiation potential of constructs made from a new cross-linked hyaluronic acid (XHA) scaffold on which different sorted subpopulations of ASCs were loaded. Thirty days after engraftment in mice, we found that NG2+ ASCs underwent a complete myogenic differentiation, fabricating a human skeletal muscle tissue, while NG2- ASCs merely formed a human adipose tissue” (see abstract). Desiderio teaches “NG2+/CD34+ and NG2-/CD34+ cells were sorted for experiments. The purity of sorted populations was routinely 90%” (see page 1764, right col. & page 1769, right col.).
Regarding claim 12 pertaining to the scaffold, Desiderio teaches human pre-adipocyte seeded HA sponges contained a higher density of cells than collagen constructs, and after 3 weeks from grafting had formed an adipose tissue (see page 1772, left col.). Desiderio teaches a scaffold construct comprising cross-linked hyaluronic acid (XHA) which reads on a hydrogel.
Madsen discloses CD264 expression inversely correlated with proliferation and differentiation potential. Madsen teaches that when CD264+ cell content was 20% to 35%, MSC cultures from young and older donors proliferated rapidly and differentiated extensively (see abstract & page 9: Discussion). Madsen further teaches that “when CD264+ cell content exceeded the 35% threshold in our MSC cultures, CD264 surface expression was inversely correlated to the proliferation and differentiation potential of the culture” (see page 9: Discussion).
It would have first been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention use or employ the scaffold such as taught by Desiderio for the teachings of O’Connor because scaffolds are well-known, routine, and commonly utilized in cell cultivation/tissue engineering for engraftment applications. Furthermore, it would have been also obvious to select or obtain a mesenchymal stem cell subpopulation of at least 70% NG2 expression and less than 30% or less than 10% CD264+ following the guidance of the cited references. The ordinary artisan would have been motivated to do so is because Russell and Desiderio suggests that stem cells expressing NG2 demonstrated tissue regenerative potential and Madsen suggests that stem cells with CD264 surface expression was inversely correlated to the proliferation and differentiation potential of the culture. Therefore, the cited references provide the rationale to select a population of MSC expressing greater NG2 and lesser amounts of CD264+ and vice versa. Accordingly, it would have been at least obvious to try because the claimed expression values are recognized as a result-effective variable, i.e., a variable which achieves a recognized result, and the presence of a known result-effective variable would be one, but not the only, motivation for a person of ordinary skill in the art to experiment to reach another workable product or process (MPEP 2144.05(II)(B)). The ordinary artisan would have had a reasonable expectation of success is because both of the cited references are directed to mesenchymal stem cell differentiation and tissue engineering applications.
Claims 11-13 and 21-22 are rejected under 35 U.S.C. 103 as being unpatentable over Russell (Cell-Surface Expression of Neuron-Glial Antigen 2 (NG2) and Melanoma Cell Adhesion Molecule (CD146) in Heterogeneous Cultures of Marrow-Derived Mesenchymal Stem Cells, 2013 - newly cited) in view of Desiderio (Human Ng2R Adipose Stem Cells Loaded In Vivo on a New Crosslinked Hyaluronic Acid-Lys Scaffold Fabricate a Skeletal Muscle Tissue, 2013) and Madsen (Decoy TRAIL receptor CD264: a cell surface marker of cellular aging for human bone marrow-derived mesenchymal stem cells, 2017) - all references in the IDS filed on 02/01/2022.
Russell’s general disclosure relates to identifying potential biomarkers for the enrichment of progenitors from heterogeneous mesenchymal stem cells (MSCs) cultures (see abstract).
Russell teaches “the present study examines variation in expression of neuron-glial antigen 2 (NG2) and melanoma cell adhesion molecule (CD146) on the surface of MSCs derived from human bone marrow in response to culture conditions and among cell populations” … “A potential relationship between proliferation and antigen expression was explored by sorting heterogeneous MSCs into rapidly and slowly dividing groups. Fluorescence-activated cell sorting revealed that rapidly dividing MSCs display lower scatter and 50% higher NG2 surface expression than slowly dividing cells, but CD146 expression is comparable in both groups. Heterogeneous MSCs were sorted based on scatter properties and surface expression of NG2 and CD146 into high (HI) and low (LO) groups. ScLONG2HI and ScLONG2HICD146HI MSCs have the highest proliferative potential of the sorted groups, with colony-forming efficiencies that are 1.5 - 2.2 times the value for the parental controls. The ScLO gate enriches for rapidly dividing cells. Addition of the NG2HI gate increases cell survival to 1.5 times the parental control. Further addition of the CD146HI gate does not significantly improve cell division or survival. The combination of low scatter and high NG2 surface expression is a promising selection criterion to enrich a proliferative phenotype from heterogeneous MSCs during ex vivo expansion, with potentially numerous applications” (see abstract & page 2258, right col. & Figure 4).
However, Russell does not teach: a scaffold (claim 11’s limitation and claim 12); or wherein less than 30% or 10% of the MSCs are CD264+ (claim 11’s limitation and claim 13); or at least 70% are CD264+ (claims 21-22).
Desiderio teaches “mesenchymal stem cell (MSC) therapy holds promise for treating diseases and tissue repair. Regeneration of skeletal muscle tissue that is lost during pathological muscle degeneration or after injuries is sustained by the production of new myofibers. Human adipose stem cells (ASCs) have been reported to regenerate muscle fibers and reconstitute the pericytic cell pool after myogenic differentiation in vitro. Our aim was to evaluate the differentiation potential of constructs made from a new cross-linked hyaluronic acid (XHA) scaffold on which different sorted subpopulations of ASCs were loaded. Thirty days after engraftment in mice, we found that NG2+ ASCs underwent a complete myogenic differentiation, fabricating a human skeletal muscle tissue, while NG2- ASCs merely formed a human adipose tissue” (see abstract). Desiderio teaches “NG2+/CD34+ and NG2-/CD34+ cells were sorted for experiments. The purity of sorted populations was routinely 90%” (see page 1764, right col. & page 1769, right col.).
Regarding claim 12 pertaining to the scaffold, Desiderio teaches human pre-adipocyte seeded HA sponges contained a higher density of cells than collagen constructs, and after 3 weeks from grafting had formed an adipose tissue (see page 1772, left col.). Desiderio teaches a scaffold construct comprising cross-linked hyaluronic acid (XHA) which reads on a hydrogel.
Madsen discloses CD264 expression inversely correlated with proliferation and differentiation potential. Madsen teaches that when CD264+ cell content was 20% to 35%, MSC cultures from young and older donors proliferated rapidly and differentiated extensively (see abstract & page 9: Discussion). Madsen further teaches that “when CD264+ cell content exceeded the 35% threshold in our MSC cultures, CD264 surface expression was inversely correlated to the proliferation and differentiation potential of the culture” (see page 9: Discussion).
It would have first been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention use or employ the scaffold such as taught by Desiderio for the teachings of Russell because scaffolds are well-known, routine, and commonly utilized in cell cultivation/tissue engineering for engraftment applications. Furthermore, it would have been also obvious to select or obtain a mesenchymal stem cell subpopulation of at least 70% NG2 expression and less than 30% or less than 10% CD264+ following the guidance of the cited references. The ordinary artisan would have been motivated to do so is because Russell and Desiderio suggests that stem cells expressing NG2 demonstrated tissue regenerative potential and Madsen suggests that stem cells with CD264 surface expression was inversely correlated to the proliferation and differentiation potential of the culture. Therefore, the cited references provide the rationale to select a population of MSC expressing greater NG2 and lesser amounts of CD264+ and vice versa. Accordingly, it would have been at least obvious to try because the claimed expression values are recognized as a result-effective variable, i.e., a variable which achieves a recognized result, and the presence of a known result-effective variable would be one, but not the only, motivation for a person of ordinary skill in the art to experiment to reach another workable product or process (MPEP 2144.05(II)(B)). The ordinary artisan would have had a reasonable expectation of success is because both of the cited references are directed to mesenchymal stem cell differentiation and tissue engineering applications.
Examiner’s Response to Arguments
Applicant’s amendments and arguments filed on 02/20/2026 have been fully considered but they are not persuasive and deemed insufficient to overcome the prior arts of record.
In response to Applicant’s amendments (addressing page 6, top ¶) that the “claims 11 and 21 have been amended to clarify that differential expression of NG2 relates to high expression of NG2 and low expression of NG2”: as an initial matter, note that the claimed invention is directed to a product or composition of matter (i.e., its statutory category of invention) where “For processes, the claim limitations will define steps or acts to be performed. For products, the claim limitations will define discrete physical structures or materials” (MPEP 2103(I)(C)). However, the claims’ language employs various product-by-process verbs including “isolated and selected”, “followed by ex vivo or in vitro expansion”, or “consists of separating MSCs” but the patentability of a product does not depend on its method of production (MPEP 2113(I)). Thus, the distinctive structural characteristics of the final claimed composition implied by the steps is difficult to ascertain for patentability. Therefore, it is requested that Applicant provides clarification to the exact structure of the claimed composition. Moreover, note in independent claim 11, at line 5, the phrase “to effectively increase an in vivo differential potential of the MSCs” is presumed to be intended as “differentiation potential” (e.g., specification at ¶ [0072]) and not differential potential. If the Examiner’s claim interpretation is incorrect, Applicant is invited to point out the meaning of “differential potential” (nor the phrase “differential expression”) because said phrase was not found after a text search in the instant specification.
In response to Applicant’s argument (addressing pages 6-7 of the remarks) that the disclosure of Desiderio relates to adipose stem cells (ASCs) which is not predictive of MSCs results where an evidentiary reference by Strioga discloses the distinction between the two cell populations: this argument is not persuasive because “one cannot show non-obviousness by attacking references individually where the rejections are based on combinations of references” (MPEP 2145(IV)). The Examiner agrees with Applicant’s assertion “that MSCs and ASCs differ in several important respects, as taught in the evidentiary Strioga reference”. However, the prior obviousness rejection was not a proposal to switch or substitute O’Connor’s MSCs cell population for Desiderio’s ASCs cell population. In other words, in the previous office action, the secondary reference by Desiderio was not used for its feature of adipose stem cells but rather, it was primarily relied upon to address the claimed feature of a scaffold (i.e., to also teach dependent claim 12 directed the specific type of scaffold material, see previous office action on page 5). In particular, the previous office action on page 6 indicated “It would have first been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention [to] use or employ the scaffold such as taught by Desiderio for the teachings of O’Connor because scaffolds are well-known, routine, and commonly utilized in cell cultivation/tissue engineering for engraftment applications”. In a basic sense, the seeding or attachment of stem cells in general onto a scaffold is a routine expedient in the art as evident by Desiderio’s disclosure where the teaching of NG2+, albeit being on ASCs, provides a reasonable concept nexus with O’Connor teachings also directed to NG2 cells. Ascertaining the differences between the prior art and the claims at issue requires interpreting the claim language, and considering both the invention and the prior art references as a whole.
In response to Applicant’s argument (addressing pages 7-8 of the remarks) that “Madsen teaches to avoid 35% or more CD264 in culture as it is a marker of aging … This is in direct contrast to claim 21”: this argument is not persuasive because Madsen does not teach absolute avoidance of greater than 35%. Rather, Madsen discloses “CD264 could be an effective indicator to select culture conditions for ex vivo expansion of MSCs” (see page 12, left col.) and also discloses “MSCs may increase CD264 expression as a means to defend against cellular senescence by promoting cell survival and growth” (see page 10, left col.). Note that the obviousness rejection indicated that “it would have been at least obvious to try because the claimed expression values are recognized as a result-effective variable, i.e., a variable which achieves a recognized result, and the presence of a known result-effective variable would be one, but not the only, motivation for a person of ordinary skill in the art to experiment to reach another workable product or process (MPEP 2144.05(II)(B))”. In the absence of unexpected results, the percentage of MSCs is deemed a result effective variable. Applicant is invited to direct the Examiner’s attention to any unexpected results for the claim 21’s phrase of “such that at least 70% of the MSCs are CD264+ to effectively increase an in vivo survival of the MSCs” in the specification.
New Grounds of Rejection Necessitated by Amendments
Claim Rejections - 35 USC §103, Obviousness
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claim 26 is rejected under 35 U.S.C. 103 as being unpatentable over 2°O’Connor (US 2017/0016898 A1 - cited in the IDS filed on 02/01/2022) in view of Gregory (US 2012/0100114 A1).
2°O’Connor’s general disclosure relates to a method of identifying aging Mesenchymal Stem Cells (MSCs) and a method of enriching a culture of MSCs with high proliferating potential (see abstract & ¶ [0003]).
O’Connor teaches strategies to “remove negative effects of senescent cells in MSCs populations and increase the efficacy of regenerative medicine by enriching healthy cell population. To separate the senescent cells from heterogeneous MSCs from bone marrow, bio-markers such as antigens Neuron-Glial Antigen 2 (NG2) and melanoma cell adhesion molecule (CD146) have been discovered. Flow cytometry is used in the sorting process. Cells with high surface expression of the antigen and cells with low surface expression of the antigen can be differentiated and separated by the flow cytometer. This method selects a proliferative phenotype
from heterogeneous MSCs during ex vivo expansion” (see ¶ [0006]-[0007]). O’Connor further teaches that “Russell et al. found that NG2 expression is uniquely correlated to rapidly dividing stem cells. Sorting using this surface receptor will enrich the sorted population by concentrating the number of rapidly dividing MSCs. Alternatively, sorting by using the death receptor can result in an enriched parent population using a totally different marker. If the death receptor indicates slowly dividing or senescent cells, then removing these cells from the population
will enable the parent population to be more robust. As mentioned above, a boosted population is extremely desirable for stem cell therapies” (see ¶ [0008]-[0009]).
O’Connor teaches the “a method of identifying multipotent mesenchymal stem cells of high proliferation potential or trilineage potential, comprising the steps of a) collecting mesenchymal stem cells, b) measuring the expression of CD264, and c) removing the mesenchymal stem cells with positive expression of CD264” (see ¶ [0025], [0017]-[0024]). Avoiding the use of MSC' s with CD264+ will enhance the effectiveness of stem cell therapies by providing more proliferation (see ¶ [0087]-[0092]).
However, 2°O’Connor does not teach: a scaffold or less than 30% of the MSCs are CD264+ (claim 11’s limitations); or wherein the scaffold is made of hydroxyapatite/tricalcium phosphate (HA/TCP) granules (claim 26).
Regarding the scaffold, Gregory’s disclosure relates supporting materials and method of making said biocompatible materials for in vivo and in situ applications (see ¶ [0003]). In particular, Gregory teaches “using a scaffold to deliver cells to the desired tissue. The cells can be seeded onto or into a three-dimensional scaffold and administered in vivo in a mammal, where the seeded cells proliferate on the framework and form a replacement tissue in vivo in cooperation with the cells of the mammal” (see ¶ [0206]-[0209]). Gregory teaches a composition comprising mesenchymal stem cells (MSCs) initially pretreated for differentiation and a three-dimensional scaffold comprising said MSCs and further include hydroxyapatite/tricalcium phosphate (HA/TCP) granules (see ¶ [0010]-[0011], [0204], [0209]). The scaffold comprises extracellular matrix selected from fibronectin (see ¶ [0207]).
It would have first been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention use or employ the scaffold such as taught by Gregory for the teachings of 2°O’Connor because scaffolds are well-known, routine, and commonly utilized in cell cultivation/tissue engineering for engraftment applications. Furthermore, it would have been also obvious to select or obtain a mesenchymal stem cell subpopulation of at least 70% NG2 expression and less than 30% of CD264+ following the guidance of the cited references. The ordinary artisan would have been motivated to do so is because O’Connor suggests that stem cells expressing NG2 demonstrated tissue regenerative potential and further suggests removal of stem cells with CD264 surface expression was correlated to the proliferation and differentiation potential of the culture. Therefore, the cited reference provide the rationale to select a population of MSC expressing greater NG2 and lesser amounts of CD264+. Accordingly, it would have been at least obvious to try because the claimed expression values are recognized as a result-effective variable, i.e., a variable which achieves a recognized result, and the presence of a known result-effective variable would be one, but not the only, motivation for a person of ordinary skill in the art to experiment to reach another workable product or process (MPEP 2144.05(II)(B)). The ordinary artisan would have had a reasonable expectation of success is because both of the cited references are directed to mesenchymal stem cell differentiation and tissue engineering applications.
Conclusion
No claims were allowed.
Applicant’s amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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 extension fee 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 date of this final action.
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/NGHI V NGUYEN/Primary Examiner, Art Unit 1653
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