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 in response to the papers filed on 06/11/2026. Claims 1-4, 6, 7, 9, 10, 12-21, 23, and 24 are currently pending as per claims filed on 06/12/2024. Applicant’s election of Group I, claims 1-4, 6, 7, 9, 10, 12-14 in the reply filed on 06/11/2026 is acknowledged. Because Applicants did not distinctly and specifically point out supposed errors in the restriction requirement, the election has been treated as an election without traverse. See MPEP § 818.03(a).
Therefore, claims 15-21, 23, and 24 are withdrawn from further consideration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.
The requirement is still deemed proper and is therefore made FINAL.
Therefore, claims 1-4, 6, 7, 9, 10, 12-14 are subject to examination to which the following grounds of rejection are applicable.
Priority
The instant application is a 371 of PCT/CA2022/051834 filed 12/15/2022
which claims benefit to US Provisional application no. 63/290,480 filed 12/16/2021.
Thus, the earliest possible priority for the instant application is 12/16/2021.
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 11/11/2024, and 10/31/2025 was filed after the mailing date of the current office action. The submission is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
Claim Objections
Claim 7 is objected to because of the recitation “(i) formed under serum- and or feeder cell-free conditions” at line 24. The phrase “and or” is not grammatically correct. Appropriate correction is required.
Claim 12 is objected to because abbreviations such as DAPT should be spelled out at the first encounter in the claims. Appropriate correction is required.
Claim Rejections - 35 USC § 112 (b)
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.
Claim 3, 4, 7, and 10 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 3 recites the phrase “and/or”. It is unclear what the metes and bounds of this term, as “and” could be interpreted to include only serum-free expansion medium, or both serum- and bovine pituitary extract-free, or, “or” would imply that the ingredients are in the alternative. Appropriate correction is required.
Claim 4 recites the phrase “and/or”. It is unclear what the metes and bounds of this term, as “and” could be interpreted to include only feeder-free conditions, or both feeder-free conditions and performed on or in a support or coating comprising one or more extracellular matrix proteins, or, “or” would imply that the steps are in the alternative. Appropriate correction is required.
Claim 7 recites the phrase “and/or”. It is unclear what the metes and bounds of this term, as “and” could be interpreted to include forming under serum- and or feeder free conditions, or both forming under serum- and or feeder free conditions and a PSC-derived hair-bearing skin organoid, or, “or” would imply that the conditions are in the alternative. Appropriate correction is required.
Claim 10 recites the phrase “and/or”. It is unclear what the metes and bounds of this term, as “and” could be interpreted to include an inhibitor of TGF-beta signaling, or both an inhibitor of TGF-beta signaling and one or more of A83-01, A77-01, and SB431542, or , “or” would imply that the inhibitors are in the alternative. Appropriate correction is required.
Claim Rejections - 35 USC § 112 (a)
Written Description
Claim 1-4, 6, 7, 9, 10, and 12-14 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.
M.P.E.P. § 2163 recites, “The written description requirement for a claimed genus may be satisfied through sufficient description of a representative number
of species by actual reduction to practice (see i)(A), above), reduction to drawings (see
i)(B), above), or by disclosure of relevant, identifying characteristics, i.e., structure or
other physical and/or chemical properties, by functional characteristics coupled with a
known or disclosed correlation between function and structure, or by a combination of
such identifying characteristics, sufficient to show the applicant was in possession of the
claimed genus (see i)(C), above). See Eli Lilly, 119 F.3d at 1568, 43 USPQ2d at 1406.”
Further, the written description inquiry is limited to that which is contained within the four corners of the specification, not the extent to which the skilled artisan, given his or her
knowledge of the art, would have considered it to expand with only routine
experimentation. See Ariad Pharms. Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1351 (Fed.
Cir. 2010) (en banc); see also id. at 1352 (“[I]t is the specification itself that must
demonstrate possession A description that merely renders the invention obvious does
not satisfy the requirement.").
Claim 1 is directed to a vast genus of differentiated pluripotent stem cells that, when contacted with expansion media comprising a vast genus of combinations of inhibitors of TGF signaling, gamma secretase inhibitors, and agents that disrupts cytoskeletal structure, can generate expanded epidermal keratinocytes.
There is not structure/function correlation for the claimed genus of differentiated pluripotent stem cells and their contact with the vast genus of combinations of inhibitors of TGF signaling, gamma secretase inhibitors, and agents that disrupt cytoskeletal structure such that they can generate expanded epidermal keratinocytes. Rather, the only structure/function correlation present is use of an undefined medium termed “DermaCultTM” (Example 3, para 0106) and HKGS medium supplemented with all three of A83-01 (a TGF beta inhibitor), DAPT (a gamma secretase inhibitor), and Y-27632 (a ROCK inhibitor), or HKGS with only Y-27632 (Fig 11, para 0120) and only when using these aforementioned media with keratinocytes derived from skin organoids derived from H1-ESC, H9-ESC, 1C-iPSC, and F022-iPSC with DermaCultTM and keratinocytes derived from skin organoids derived from H9-ESC and 1C-iPSC with HKGS medium supplemented with all three of A83-01, DAPT, and Y-27632. (Fig 11). Indeed, these cell types and corresponding medium were the only combinations that yielded expanded keratinocytes. Thus, the specification only teaches a method of expanding keratinocytes comprising contacting keratinocytes derived from skin organoids with basal medium comprising only Y-27632 (i.e. agent that disrupts cytoskeletal structure) or the combination of all three A83-01, DAPT, and Y-27632.
The specification does not disclose that any other type of combination of inhibitors of TGF signaling, gamma secretase inhibitor, or agent that disrupts cytoskeletal structure, other than A83-01, DAPT, and Y-27632, respectively, would result in the function of expanding epidermal keratinocytes. Therefore, it is unclear if the disclosed method will provide the same function as the disclosed invention.
The prior art discloses specific combinations agents for expansion of epidermal keratinocytes and explicit timing of exposure. For example, Zhong et al (Int. J. Biol. Sci. 2020, pages 1450-1462) teaches that expansion of epidermal keratinocytes requires precise stepwise exposure of differentiating pluripotent stem cells to the specific agents SB431542 (TGF inhibitor) and DAPT (gamma secretase inhibitor) and requires the combinations of these agents to be at specific timepoints of culture. For instance, Figure 1 of Zhong teaches contacting the differentiating pluripotent stem cells with SB431542 and DAPT occurs between day 4-6, but only DAPT is present from day 6-8, and there is no inclusion of an agent that disrupts cytoskeletal structure (i.e. a ROCK inhibitor). Ali et al (STAR Protoc. 2022, pages 1-10) teaches a method of differentiation human pluripotent stem cells into epidermal keratinocytes, including the passage (i.e. expansion) of final stage epidermal keratinocytes, and the expansion step (step 14), does not include any of the TGF signaling inhibitors, gamma secretase inhibitors, and agents that disrupt cytoskeletal structure, or any combination thereof (page 4, Differentiation of keratinocyte progenitor cells into mature keratinocyte-like cells). Indeed, no aspect of the methodology of Ali uses any TGF signaling inhibitors, gamma secretase inhibitors, and agents that disrupt cytoskeletal structure, or any combination thereof. Thus, there is no indication that the structure of any combination of TGF signaling inhibitors, gamma secretase inhibitors, and agents that disrupt cytoskeletal structure, and any type of each of these inhibitors/agents, would elicit the function of expanding epidermal keratinocytes.
Applicant were referred to the guidelines for Written Description Requirement
published January 5, 2001 in the Federal Register, Vol.66, No.4, pp.1099-1110 (see
http://www.uspto.gov). The disclosure of a single species is rarely, if ever, sufficient to
describe a broad genus, particularly when the specification fails to describe the features
of that genus, even in passing. (see In re Shokal 113USPQ283(CCPA1957); Purdue
Pharma L. P. vs Faulding Inc. 56 USPQ2nd 1481 (CAFC 2000). The possession may
be shown by actual reduction to practice, clear depiction of the invention in a detailed
drawing, or by describing the invention with sufficient relevant identifying characteristics
(as it relates to the claimed invention as a whole) such that a person skilled in the art
would recognize that the inventor had possession of the claimed invention. See, e.g.,
Pfaff v. WellsElectronics, Inc., 525 U.S. 55, 68, 119 S.Ct. 304, 312, 48 USPQ2d 1641,
1647 (1998); Eli Lilly, 119 F.3d at 1568, 43 USPQ2d at 1406; Amgen, Inc. v. Chugai
Pharmaceutical, 927 F.2d 1200, 1206, 18 USPQ2d 1016, 1021 (Fed. Cir. 1991).
The “written description” requirement may be satisfied by using such descriptive
means as words, structures, figures, diagrams, formulas, etc., that fully set forth the
claimed invention. See Noelle v. Lederman, 355 F.3d 1343, 1349, 69 USPQ2d 1508,
1514 (Fed. Cir. 2004) and Lockwood v. American Airlines, Inc., 107 F.3d at 1572, 41
U.S.P.Q.2d at 1966. A definition by function alone “does not suffice” to sufficiently describe a coding sequence “because it is only an indication of what the gene does,
rather than what it is.” Regents of the University of California v. Eli Lilly & Co., 119 F.3 at
1568, 43 USPQ2d at 1406 (Fed. Cir. 1997) (discussing Amgen Inc. v. Chugai
Pharmaceutical Co., 927 F.2d 1200, 18 U.S.P.Q.2d 1016 (Fed. Cir. 1991)). In Fiers v.
Ravel, 984 F.2d at 1169-71, 25 U.S.P.Q.2d at 1605-06 (1993), the CAFC found that “a
mere wish or plan for obtaining the claimed chemical invention” is not sufficient to
describe a chemical invention (discussed in Eli Lilly at 1404).
In the instant application, the only method disclosed is for expanding keratinocytes by contacting keratinocytes derived from skin organoids in basal medium comprising all three of A83-01 (a TGF beta inhibitor), DAPT (a gamma secretase inhibitor), and Y-27632 (a ROCK inhibitor). Therefore, the limited disclosure in the
specification is not deemed sufficient to reasonably convey to one skilled in the art that
the applicants were in possessions of the huge genera of combinations recited in the claims at the time
the application was filed. Thus, it is concluded that the written description requirement is
not satisfied for the claimed genera.
Claim Interpretation
Claim 1 and 2 recite “one or more of an inhibitor of TGF signaling, a gamma secretase inhibitor, and an agent that disrupts cytoskeletal structure” and “two or more of an inhibitor of TGF signaling, a gamma secretase inhibitor, and an agent that disrupts cytoskeletal structure”, respectively. The examiner is interpreting these phrases to mean there must be one or more (claim 1) or two or more (claim 2) types of inhibitors of TGF signaling, in addition to a gamma secretase inhibitor, and an agent that disrupts cytoskeletal structure in the basal medium.
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.
Claim(s) 1-4, 6, 7, 9, 10, and 12-14 are rejected under 35 U.S.C. 103 as being unpatentable over Zhong et al (Int. Journal. of Biological Sci, 2020, pages 1450-1462; as cited in IDS), as evidenced by Corning (Matrigel Matrix, downloaded 06/22/2026, published in 2019), and further in view of Lee et al (Nature, 2020, pages 1-37/pages 399-427) and McMullan et al (Current Biology, 2003, pages 2185–2189).
Regarding claim 1, 10, 12-14, Zhong teaches a method of differentiating human pluripotent stem cells (PSCs) into epidermal keratinocytes in a monolayer culture system by contacting the PSCs with a differentiation medium comprising DMEM/F12 (i.e. a basal medium) supplemented with 10μM SB431542 (i.e. a TGF signaling inhibitor) from day 0-6 and 5 μM DAPT (a gamma secretase inhibitor) from day 4-8, and, upon continued culture, results in stage Ⅲ keratinocytes (page 1451, right col, Keratinocyte differentiation in monolayer), hence Zhong anticipates a method of expanding epidermal keratinocytes, the method comprising: contacting a differentiated population of pluripotent stem cells (PSCs) which are epidermal keratinocytes with an expansion medium comprising a basal medium an inhibitor of transformation growth factor (TGF) signaling and a gamma secretase inhibitor to obtain stage Ⅲ keratinocytes (claim 1), wherein the inhibitor of TGF signaling is SB431542 (claim 10), and wherein the gamma secretase inhibitor is DAPT (claim 12) .
Zhong does not teach the basal medium further comprising an agent that disrupts cytoskeletal structure (claim 1) and wherein the agent that disrupts cytoskeletal structure is a Rho/Rock kinase inhibitor (claim 13) and the Rho/Rock kinase inhibitor is Y-27632 (claim 14).
However, one of ordinary skill in the art would have considered the teachings of
McMullan as the reference is analogous prior art pertaining to using ROCK inhibitors, which disrupt cytoskeletal structure, and the importance of ROCK inhibition in keratinocyte differentiation.
McMullan teaches “GTP binding protein RhoA plays a fundamental role in the regulation of the actin cytoskeleton and in the adhesion events that are critically important to normal tissue homeostasis” and ROCK is involved in the cytoskeletal changes take place during epidermal stratification (Summary, page 2185; page 2189, left col, para 2). McMullan teaches that Rho’s downstream effector, ROCK, plays a role in epidermal keratinocyte function and teaches that the use of the pharmacological inhibitor of ROCK, Y-27632, results in inhibition of keratinocyte terminal differentiation and an increase in cell proliferation, thus ROCK plays a fundamental part in keratinocyte differentiation and fate (page 1-2, Results and Discussion: Inhibition of ROCK Prevents Keratinocyte Terminal Differentiation and Inhibition of ROCK Results in Increased Keratinocyte Proliferation, and Summary).
It would have been prima facie obvious to one of ordinary skill, in the art at the time of the effective filing date, to modify the teachings of Zhong to include the ROCK inhibitor Y-27632 in the expansion medium since McMullan taught that ROCK was important in the regulation of keratinocyte differentiation and fate and caused decreased terminal differentiation and increased cell proliferation. One would be motivated to do so to maximize the number of keratinocytes generated by the expansion method since decreased terminal differentiation and increased proliferation would result in more keratinocytes. As use of ROCK inhibitors in cell culture is routine in the art, one would have a reasonable expectation of success.
Regarding claim 2, the teachings of Zhong and McMullan render obvious claim 1.
The combined teachings of Zhong and McMullan do not teach where in the expansion medium comprises two or more of the inhibitor of TGF signaling.
Suzuki teaches that LY364947, which is a TGFβ signaling inhibitor, enhances the growth and expansion of human epidermal keratinocytes during in vitro culture (page 3, Results, para 6).
It would have been prima facie obvious to one of ordinary skill, in the art at the time of the effective filing date, to modify the teachings of Zhong to include a second TGF signaling inhibitor as Suzuki taught that LY364947, which is a TGFβ signaling inhibitor, enhances the growth and expansion of human epidermal keratinocytes during in vitro culture by incorporating the additional function of an inhibitor of TGF signaling. One would be motivated to do so to increase the additional effect of two or more of the inhibitors of TGF signaling to enhance yield of epidermal keratinocytes generated by in vitro culture for downstream applications. As culture of epidermal keratinocytes with TGF signaling inhibitors and differentiated pluripotent stem cells is known in the art before the effective filing date of the claimed invention, one would have a reasonable expectation of success.
Regarding claim 3, the teachings of Zhong and McMullan render obvious claim 1. Moreover, Zhong teaches that the differentiation medium is free of serum and bovine pituitary extract (page 1451, right col, Keratinocyte differentiation in monolayer), hence Zhong discloses wherein the expansion medium is serum- and/or bovine pituitary extract-free.
Regarding claim 4 the teachings of Zhong and McMullan render obvious claim 1. Moreover, Zhong teaches that the human ESCs were cultured on Matrigel-coated plates (i.e. an extracellular matrix coating containing a mixture of extracellular matrix proteins as evidenced by Corning (page 1, downloaded 06/22/2026) until 30% confluency and then switched to differentiation medium (i.e. still cultured on the Matrigel), and the cells were not cultured on feeder cells (page 1451, right col, Human ESC culture and Keratinocyte differentiation in monolayer), hence Zhong renders obvious wherein the contacting and the culturing steps are: (i) in feeder cell free conditions; and/or (ii) performed on or in a support or coating comprising one or more extracellular matrix proteins.
Regarding claim 6 and 7, the teachings of Zhong anticipate claim 1.
Zhong does not teach the method of claim 1 further comprising dissociating a PSC-derived skin organoid to obtain the differentiated population of PSCs (claim 6) and wherein the PSC-derived skin organoid is; (i) formed under serum- and or feeder cell-free conditions; and/or (ii) a PSC-derived hair-bearing skin organoid (claim 7).
However, one of ordinary skill in the art would have considered the teachings of
Lee as the reference is analogous prior art pertaining to methods of generating hair-bearing skin organoids and dissociation of skin organoids to retrieve differentiated stem cells.
Lee teaches a method of generating skin organoids from pluripotent stem cells under feeder-free and serum-free conditions (page 7, Optimized differentiation of human pluripotent stem cells) and dissociation of skin organoids could yield 1,000 differentiated cells per μl and had a cell viability of greater than 90 (page 8-9, Skin organoid dissociation for scRNA-seq) and that after 70 days of culture, skin organoids reached the hair-bearing stage (page 3, para 3). Lee teaches that the organoids are comprised of keratinocytes cells of the following subtypes: basal, intermediate, and peridermal (page 4, para 2).
It would have been prima facie obvious to one of ordinary skill, in the art at the time of the effective filing date, to modify the teachings of Zhong for a method of expanding keratinocytes to use differentiated pluripotent stem cells obtained after dissociation of skin organoids since Lee teaches a method of dissociation of skin organoids that are comprised of keratinocytes and could yield 1,000 differentiated cells per μl with high viability and the organoids were able to differentiate to the skin-bearing stage of development. One would be motivated to do so to more efficiently obtain a reasonable amount of viable cells that have already entered differentiation from skin organoid culture to use for keratinocyte expansion culture. As skin organoid culture, keratinocyte differentiation, and organoid dissociation have been demonstrated in the prior art, one would have a reasonable expectation of success.
Regarding claim 9, the teachings of Zhong and McMullan render obvious claim 1. It is noted that the claim 9 recites a result (i.e. “yielding more epidermal keratinocytes than contaminating cell types when the contacting and the culturing steps are performed in the expansion medium”) based on the methodology of claim 1. While Zhong does not explicitly recite that cells cultured in the differentiation medium yielding more epidermal keratinocytes than contaminating cell types compared to a basal medium, the results are reasonably expected based on the methodology of expanding the epidermal keratinocytes with the claimed expansion medium.
It is noted that In re Best (195 USPQ 430) and In re Fitzgerald (205 USPQ 594) discuss the support of rejections wherein the prior art discloses subject matter which there is reason to believe inherently includes functions that are newly cited or is identical to a product instantly claimed. In such a situation the burden is shifted to the applicants to "prove that subject matter shown to be in the prior art does not possess characteristic relied on" (205 USPQ 594, second column, first full paragraph). It is noted that, if the prior art discloses identical chemical structure, the properties applicant discloses and/or claims are necessarily present, In re Spada, 911 F.2d 705, 709, 15 USPQ2d. As such, the functional limitations would be expected in the identical methodology taught by Zhong and would therefore elicit these results whenever the methodology would be employed.
Conclusion
No claims are allowed.
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/JULIANA IRENE CANDELARIA/Examiner, Art Unit 1634
/MARIA G LEAVITT/Supervisory Patent Examiner, Art Unit 1634
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