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 .
This action is responsive to papers filed 07/09/2026.
No claims have been amended. Claim 4 has been newly canceled and no claims have been newly added.
Claims 1, 3, and 5-20 are currently pending.
Claims 8-14 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim.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 07/16/2025.
Claims 1, 3, 5-7 and 15-20 have been examined on their merits.
Rejections and/or objections not reiterated from previous office actions are hereby withdrawn due to the cancelation of claim 4. The following rejections and/or objections are either reiterated or newly applied. They constitute the complete set presently being applied to the instant application.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim(s) 1, 3, 5-7, and 15-20 are rejected under 35 U.S.C. 103 as being unpatentable over Dai et al (Cell Transplantation, 2018) in view of Cao et al (WO 2016/209166-from IDS filed 08/20/2022) and as evidenced by Zajkowska et al (Pathology and Oncology Research 2019).
Regarding claims 1, 3 and 5-7, Dai disclose a method of developing a pre-vascularized three-dimensional skin substitute using blood plasma gel (hydrogel of exclusively biological origin) (Title, abstract, page 1536). Dai disclose mixing fibroblasts, endothelial progenitor cells (EPCs, immature endothelial cells) and hydrogel and incubating in a culture medium for 7 days (at least 6 days) and under suitable conditions to obtain a pre-vascularized dermis tissue and adding keratinocytes to the pre-vascularized dermis tissue to obtain a skin substitute where no vascular smooth muscle cell is added to the mixture (page 1536-1567). The differentiation of EPCs to endothelial cells (more mature endothelial cells) was confirmed (page 1537). The human blood plasma gel used in the method (page 1536) will inherently contain VEGF as evidenced by Zajkowska (Title and abstract).
Dai do not teach wherein the fibroblast, endothelial cells and keratinocytes were obtained from pluripotent stem cells.
Cao disclose methods of making skin substitutes using fibroblasts, endothelial cells and keratinocytes all of which originated by pluripotent stem cells, specifically human induced pluripotent stem cells (page 3 line 25-page 4 line 26). The use of human pluripotent stem cells advantageously permits consistent epidermal and full-thickness skin or mucosal equivalents populated with dermal and epidermal cells with the requisite barrier properties to be generated by providing potentially an unlimited source of skin cells. Further incorporation of human pluripotent stem cell lines into skin equivalents, they offer a truer reflection of the cellular phenotypes observed in vivo (page 4 lines 19-26).
Therefore, one of ordinary skill in the art would have been motivated to obtain the fibroblasts, endothelial cells and keratinocytes for the pre-vascularized skin substitute of Dai from a human pluripotent stem cell line because Cao teach and suggest this is a beneficial and advantageous source for these cells for use in a skin substitute. The use of human pluripotent stem cells advantageously permits consistent epidermal and full-thickness skin or mucosal equivalents populated with dermal and epidermal cells with the requisite barrier properties to be generated by providing potentially an unlimited source of skin cells. Further incorporation of human pluripotent stem cell lines into skin equivalents, they offer a truer reflection of the cellular phenotypes observed in vivo (page 4 lines 19-26). One of ordinary skill in the art would have had a reasonable expectation of success because both Dai and Cao are drawn to skin substitutes that utilize fibroblast, endothelial cells and keratinocytes.
While Dai does not specifically include the use of mature endothelial cells in their mixing step with the fibroblasts and hydrogel, one of ordinary skill in the art would have been motivated to further include mature endothelial cells or substitute the mature endothelial cells from a cell line such as HUVECs because Cao also demonstrate that mature endothelial cells are a suitable option for a skin substitute. One of ordinary skill in the art would have had a reasonable expectation of success because Dai state that the 3D gel developed in their study provided for an adaptive niche for EPCs and fibroblasts that supported cell proliferation and enhanced the microvascular network structure and integrity (page 1545).
Dai do not teach incubating the skin substitute at an air-liquid interface for a sufficient time to obtain a pluristratified pre-vascularized dermal-epidermal tissue.
Cao disclose that incubating a skin substitute at an air-liquid interface for three weeks (a sufficient time) to obtain a vascularized dermal-epidermal tissue with stratification (pluristratified) is beneficial and desirable and results in the formation of a reliable and realistic skin equivalent with superior stability and longevity which has application in reconstructive skin surgery (page 9 lines 4-15, page 12, lines 32-34, page 13 lines 1-10, page 24 lines 22).
Cao specifically points out that the benefits of the air-liquid interface are found in the advantageous formation of a stable dermal layer in the cell support substrate, leading the keratinocytes demonstrating apical-basal polarity in their differentiation resulting in the development of functional keratinised or non-keratinised surfaces with epidermal stratification as seen in vivo and that benefits to the fibroblasts can be explored (page 12, lines 32-34, page 13 lines 1-10).
One of ordinary skill in the art would have been motivated to include incubating the skin substitute at an air-liquid interface for a sufficient time to obtain a pluristratified pre-vascularized dermal-epidermal tissue because Cao teach and suggest that this is a beneficial technique to use when forming a skin substitute because it results in the formation of a reliable and realistic skin equivalent with superior stability and longevity which has application in reconstructive skin surgery (page 9 lines 4-15, page 12, lines 32-34, page 13 lines 1-10, page 24 lines 22). One of ordinary skill in the art would have had a reasonable expectation of success because both Dai and Cao are drawn to skin substitutes that utilize fibroblast, endothelial cells and keratinocytes.
Regarding claims 1, 5 and 15-20, Dai do not explicitly disclose culturing or incubating the cells in a culture medium containing VEGF, however Dai do disclose using culture medium supplemented with fetal bovine serum which is known to contain some amount of VEGF. Therefore, it would appear that at least some VEGF is present in the culturing and incubation steps of Dai.
Cao disclose that culture medium containing 5-50 ng/ml VEGF is suitable for use when culturing cells for a skin substitute (page 20 lines 1-23).
One of ordinary skill in the art would have been motivated to use a culture medium that contains an optimal amount of VEGF, such as 30-50 ng.ml in the culture medium of Dai because Cao teach and suggest that serum-free culture media that contain growth supplements such as VEGF are advantageous and beneficial because they allow for the minimal use of animal-derived proteins (page 5 lines 1-10). The range of 30-50 ng/ml falls within the suggested range of Cao and at least overlaps with the claimed ranges and thus renders them obvious (see MPEP 2144.05). The use of a stabilized VEGF would have been obviously preferred because Cao repeatedly states that the stability of the skin substitute is of importance (page 3 lines 16-21, page 13 lines 1-2 and lines 8-10). One of ordinary skill in the art would have had a reasonable expectation of success because both Dai and Cao are drawn to skin substitutes that utilize and culture fibroblast, endothelial cells and keratinocytes.
Therefore, the combined teachings of Dai et al and Cao et al render obvious Applicant’s invention as claimed.
Response to Arguments
Applicant's arguments filed 07/09/2026 have been fully considered but they are not persuasive.
Applicant argues that the declaration of Inventor Christine Baldeschi demonstrates the nonobviousness of the present invention. Applicant asserts that Cao teaches a pericyte/smooth-muscle-cell dependent approach to stable vascularization which is contrary to claim 1 which expressly excludes addition of vascular smooth muscle cells to the mixture. Applicant asserts that there would be no reasonable expectation of success in modifying Dai to include features of Cao while omitting the very vascular smooth muscle cell/pericytes that Cao identifies as important for vessel maturation and stability. Applicant asserts that no combination of the cited references would make the claimed invention obvious.
This is not found persuasive. The test for obviousness is not whether the features of a secondary reference may be bodily incorporated into the structure of the primary reference; nor is it that the claimed invention must be expressly suggested in any one or all of the references. Rather, the test is what the combined teachings of the references would have suggested to those of ordinary skill in the art. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981).
In the current case, while the Cao method requires the adding of either pericytes or vascular smooth muscle cells to their method and product, the Dai method does not. Cao is only relied upon in the obviousness rejection to demonstrate that it was known in the art of in vitro skin substitutes to utilize endothelial cells, endothelial progenitor cells, fibroblast and keratinocytes obtained from human induced pluripotent stem cells, the optimal concentrations of VEGF to use when selecting the benefits of a serum-free culture medium, and the benefits of using an air-liquid interface when culturing a skin substitute as explained above.
The declaration states that Dai does not teach or suggest the claimed process because Dai does not teach all the limitations cited in the claims.
This is not found persuasive. 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).
In the current case the obviousness rejection is made based on the modification of the Dai method by the teachings and suggestion of Cao as described above.
The declaration states that Zajkowska does not cure the deficiencies of Dai. The declaration states that Zajkowska provides no teaching that would have led a skilled artisan to modify Dai in the manner of claim 1.
This is not found persuasive. 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).
In the current case, the Zajkowska is only relied upon as an evidence reference as described above.
The declaration states that Cao does not provide the missing teaching in a manner that would render the claimed process obvious. The declaration states that Cao’s organotypic vascularized skin model is built around a different vascularization strategy that includes smooth muscle cells/pericytes and expressly requires inducing cells from pluripotent stem cells and then seeding these cells to induce formation of a vascularized dermal layer. The declaration states that this requirement is not incidental. The declaration states that Cao’s explanation regarding the recruitment of mural cells to developing endothelial vessels is critical for the Cao method. The declaration states that Cao therefore teaches a pericyte/smooth muscle cell dependent approach to stable vascularization whereas claim 1 expressly excludes addition of vascular smooth muscle cells to the mixture.
This is not found persuasive. 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).
In the current case the obviousness rejection is made based on the modification of the Dai method by the teachings and suggestion of Cao as described above. In addition, Cao requires either pericytes or vascular smooth muscle cells. Pericytes are not vascular smooth muscle cells and are not excluded from the claimed method nor are they required by the Dai method.
The declaration states that the rejection treats Cao’s teachings regarding pluripotent stem cell derived sources, VEGF-containing media, and air-liquid interface culture as separable features that could be transplanted into Dai. The declaration states that the relevant question is whether the cited art would have provided an articulated reason with a reasonable expectation of success to arrive at the claimed process as a whole.
This is not found persuasive. Cao disclose methods of making skin substitutes using fibroblasts, endothelial cells and keratinocytes all of which originated by pluripotent stem cells, specifically human induced pluripotent stem cells (page 3 line 25-page 4 line 26). The use of human pluripotent stem cells advantageously permits consistent epidermal and full-thickness skin or mucosal equivalents populated with dermal and epidermal cells with the requisite barrier properties to be generated by providing potentially an unlimited source of skin cells. Further incorporation of human pluripotent stem cell lines into skin equivalents, they offer a truer reflection of the cellular phenotypes observed in vivo (page 4 lines 19-26).
Therefore, one of ordinary skill in the art would have been motivated to obtain the fibroblasts, endothelial cells and keratinocytes for the pre-vascularized skin substitute of Dai from a human pluripotent stem cell line because Cao teach and suggest this is a beneficial and advantageous source for these cells for use in a skin substitute. The use of human pluripotent stem cells advantageously permits consistent epidermal and full-thickness skin or mucosal equivalents populated with dermal and epidermal cells with the requisite barrier properties to be generated by providing potentially an unlimited source of skin cells. Further incorporation of human pluripotent stem cell lines into skin equivalents, they offer a truer reflection of the cellular phenotypes observed in vivo (page 4 lines 19-26). One of ordinary skill in the art would have had a reasonable expectation of success because both Dai and Cao are drawn to skin substitutes that utilize fibroblast, endothelial cells and keratinocytes.
Cao specifically points out that the benefits of the air-liquid interface are found in the advantageous formation of a stable dermal layer in the cell support substrate, leading the keratinocytes demonstrating apical-basal polarity in their differentiation resulting in the development of functional keratinised or non-keratinised surfaces with epidermal stratification as seen in vivo and that benefits to the fibroblasts can be explored (page 12, lines 32-34, page 13 lines 1-10).
One of ordinary skill in the art would have been motivated to include incubating the skin substitute at an air-liquid interface for a sufficient time to obtain a pluristratified pre-vascularized dermal-epidermal tissue because Cao teach and suggest that this is a beneficial technique to use when forming a skin substitute because it results in the formation of a reliable and realistic skin equivalent with superior stability and longevity which has application in reconstructive skin surgery (page 9 lines 4-15, page 12, lines 32-34, page 13 lines 1-10, page 24 lines 22). One of ordinary skill in the art would have had a reasonable expectation of success because both Dai and Cao are drawn to skin substitutes that utilize fibroblast, endothelial cells and keratinocytes.
The declaration states that the cited references point in different technical directions. The declaration asserts that a skilled artisan would not have reasonably expected that Cao’s PSC-derived cells, VEGF-supplemented, air-liquid interface system could simply be applied to Dai while omitting the very vascular smooth muscle cell/pericytes that Cao identifies as important for vessel maturation and stability.
This is not found persuasive. The test for obviousness is not whether the features of a secondary reference may be bodily incorporated into the structure of the primary reference; nor is it that the claimed invention must be expressly suggested in any one or all of the references. Rather, the test is what the combined teachings of the references would have suggested to those of ordinary skill in the art. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981).
In the current case, Dai does not require pericytes or vascular smooth muscle cells. Also Cao indicates that pericytes are an alternative to vascular smooth muscle cells.
The declaration assert that the Examiner fails to provide an articulated reason why a person of ordinary skill would have made the specific claimed combination with a reasonable expectation of success.
This is not found persuasive. Cao disclose methods of making skin substitutes using fibroblasts, endothelial cells and keratinocytes all of which originated by pluripotent stem cells, specifically human induced pluripotent stem cells (page 3 line 25-page 4 line 26). The use of human pluripotent stem cells advantageously permits consistent epidermal and full-thickness skin or mucosal equivalents populated with dermal and epidermal cells with the requisite barrier properties to be generated by providing potentially an unlimited source of skin cells. Further incorporation of human pluripotent stem cell lines into skin equivalents, they offer a truer reflection of the cellular phenotypes observed in vivo (page 4 lines 19-26).
Therefore, one of ordinary skill in the art would have been motivated to obtain the fibroblasts, endothelial cells and keratinocytes for the pre-vascularized skin substitute of Dai from a human pluripotent stem cell line because Cao teach and suggest this is a beneficial and advantageous source for these cells for use in a skin substitute. The use of human pluripotent stem cells advantageously permits consistent epidermal and full-thickness skin or mucosal equivalents populated with dermal and epidermal cells with the requisite barrier properties to be generated by providing potentially an unlimited source of skin cells. Further incorporation of human pluripotent stem cell lines into skin equivalents, they offer a truer reflection of the cellular phenotypes observed in vivo (page 4 lines 19-26). One of ordinary skill in the art would have had a reasonable expectation of success because both Dai and Cao are drawn to skin substitutes that utilize fibroblast, endothelial cells and keratinocytes.
Cao specifically points out that the benefits of the air-liquid interface are found in the advantageous formation of a stable dermal layer in the cell support substrate, leading the keratinocytes demonstrating apical-basal polarity in their differentiation resulting in the development of functional keratinised or non-keratinised surfaces with epidermal stratification as seen in vivo and that benefits to the fibroblasts can be explored (page 12, lines 32-34, page 13 lines 1-10).
One of ordinary skill in the art would have been motivated to include incubating the skin substitute at an air-liquid interface for a sufficient time to obtain a pluristratified pre-vascularized dermal-epidermal tissue because Cao teach and suggest that this is a beneficial technique to use when forming a skin substitute because it results in the formation of a reliable and realistic skin equivalent with superior stability and longevity which has application in reconstructive skin surgery (page 9 lines 4-15, page 12, lines 32-34, page 13 lines 1-10, page 24 lines 22). One of ordinary skill in the art would have had a reasonable expectation of success because both Dai and Cao are drawn to skin substitutes that utilize fibroblast, endothelial cells and keratinocytes.
The declaration states that Cao’s teaching is insufficient to establish that a skilled artisan would have used the Cao conditions in the Dai method. The declaration asserts that Cao’s own data concerning regression of endothelial networks without pericytes undermines any reasonable expectation that the modified process would yield the claimed pluristratified pre-vascularized dermal-epidermal tissue.
This is not found persuasive. The test for obviousness is not whether the features of a secondary reference may be bodily incorporated into the structure of the primary reference; nor is it that the claimed invention must be expressly suggested in any one or all of the references. Rather, the test is what the combined teachings of the references would have suggested to those of ordinary skill in the art. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981).
In addition, Cao indicates that pericytes are an alternative to vascular smooth muscle cells and the claimed invention does not exclude pericytes.
The declaration states that the specification explains that WO 2016/209166 teaches that smooth muscle cells/pericytes are necessary to combine with endothelial cells to obtain functional and lasting vascularization, and that the inventors surprisingly demonstrated that a pre-vascularized dermis and pre-vascularized dermal-epidermal tissue can be obtained from endothelial cells and fibroblasts derived from pluripotent stem cells in the absence of smooth muscle cells/pericytes. The declaration states that the claimed process is not a routine use of Cao’s systems, but depart from the pericyte/smooth muscle cell requirement taught by Cao.
This is not found persuasive. The obviousness rejection is made based on the modification of the Dai method which does not require pericytes or vascular smooth muscle cells as described above. There is no evidence to support Applicant’s assertion of surprising and unexpected results.
The declaration under 37 CFR 1.132 filed 07/09/2026 is insufficient to overcome the rejection of claims 1, 3, 5-7 and 15-20 based upon Dai et al in view of Cao and Zajkowska as set forth in the last Office action because: the evidence of obviousness is deemed to outweigh Applicant’s assertions of nonobviousness. The Dai reference method does not require vascular smooth muscle cells and the claim limitations missing from the Dai reference method are shown to be known in the prior art as shown by Cao as described above.
In view of the foregoing, when all of the evidence is considered, the totality of the rebuttal evidence of nonobviousness fails to outweigh the evidence of obviousness.
Conclusion
No claims are allowed.
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Yee et al., “The Air Liquid-interface, a Skin Microenvironment, Promotes Growth of Melanoma Cells, but not Their Apoptosis and Invasion, through Activation of Mitogen-activated Protein Kinase”, Acta Histochem. Cytochem., 2010, 43 (1): 1–7.
Discloses that a culture system with an air-liquid interface is a common microenvironment of the skin and promotes the growth and differentiation of normal keratinocytes (see page 1).
Beilmann et al., “Human primary co-culture angiogenesis assay reveals additive stimulation and different angiogenic properties of VEGF and HGF”, Cytokine, 2004, Vol. 26, pp. 178–185.
Discloses the use of VEGF to culture endothelial cells and fibroblasts (abstract).
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 LAURA J SCHUBERG whose telephone number is (571)272-3347. The examiner can normally be reached 8:30-5:00 EST.
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LAURA J. SCHUBERG
Primary Examiner
Art Unit 1631
/LAURA SCHUBERG/Primary Examiner, Art Unit 1631
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