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 .
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 1-14 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.
Claims 1, 7, and 14 all refer to “uPAR+ and nestin+ stem cells.” It is unclear whether the claims refer to a mixture of uPAR+ stem cells and nestin+ stem cells or to a single population of stem cells that are both uPAR+ and nestin+. The specification refers to “uPAR+/nestin+ stem cells” (paragraph 1) but also shows that different cells express these two markers (Figure 2, e.g.) The scope of the claims cannot be properly determined. Clarification is required.
Claims 1 and 7 refer to a “provisional matrix-mimicking hydrogel.” The plain meaning of the word “provisional” is “serving for the time being” or “temporary.” The claims do not provide any indication of how the hydrogel is “provisional” or how long a hydrogel must last to be considered “provisional.” The relationship between the hydrogel and the passage of time is unclear. See MPEP 2173.05(b).
Claims 2-6 and 8-13 depend variously from claims 1 and 7 and do not resolve the indefiniteness, so they must also be rejected under 35 U.S.C. 112(b).
Claims 3 and 9 make requirements about “the tissue,” but it is unclear whether that limitation refers only to the “tissue-resident” aspect of the preamble or whether the claims seek to further define the scope of the “isolated tissue fragments” encapsulated by the hydrogel.
Claim 13 requires that the “tissue fragments” . . . “further comprises a process of repeating steps (2) to (5) 1 to 10 times.” It is unclear how tissue fragments can comprise a process. Clarification is required.
Claim 14 requires that the stem cells be both “tissue-resident” and “isolated.” It is unclear whether the stem cells are present within tissue or whether they have been isolated and cultured. These options are mutually exclusive of each other. Clarification is required.
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 1-14 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.
Claim 1 is interpreted for this rejection as a method of inducing tissue-resident stem cells that are uPAR+ and/or nestin+ to enter the cell cycle by encapsulating isolated tissue fragments into “a provisional matrix-mimicking hydrogel,” then “3D culturing” the hydrogel “in a culture medium to which plasminogen activator inhibitor (PAI) is added.” Claim 7 recites these same steps and adds steps of removing the PAI, then reculturing the resulting culture with PAI-free culture medium to degrade the hydrogel and isolating released stem cells. Both claims 1 and 7, however, require that the method generates stem cells that are uPAR+ and/or nestin+ that have entered the cell cycle. As such, the conditions of the methods must result in that outcome. Specifically, the “3D culturing” step must produce stem cells that are uPAR+ and/or nestin+. One interpretation of claim 14 is that it includes single cells that express both uPAR and nestin. The skilled artisan would not have appreciated that applicants possessed the full breadth of the invention as it is claimed.
Claims 1 and 7 are open to all hydrogels that have at least one property of a matrix and that exist for at least some time; they are not limited to, for example, hydrogels that are degraded by plasminogen in the absence of a PAI in the culture medium. They are also open to all types of tissue fragments (compare claims 3 and 9, which limit the tissue types) and do not require that any uPAR+ or nestin+ cells be present in the tissue at the time of encapsulation. They also fail to specify the conditions under which the “3D culturing” induces cell-cycle entry by uPAR+ stem cells, nestin+ stem cells, or uPAR+/nestin+ stem cells.
Around the claims’ effective filing date, skilled artisans recognized nestin as a marker of neural stem and progenitor cells in the central nervous system. See Wang et al. (2021, Molecular Cancer Research 19:1651-1665; reference U) at abstract; Agbay et al. (US 20200399594, reference A) at paragraph 325. Skilled artisans understood uPAR (urokinase plasminogen activator receptor) to be a regulator of glioblastoma stem cell (GSC) division and self-renewal. See Habic et al. (2021, Journal of Histochemistry and Cytochemistry 69: 775-794; reference V) at page 780, column 1; Gutova et al. (US 20070244046; reference B) at paragraph 41.
The scope of the cells manipulated in the claimed method is unclear, as discussed above with respect to 35 U.S.C. 112(b), because it is unclear whether the population is a mixture of nestin+ cells and uPAR+ cells or a homogeneous population that expresses both. Skilled artisans were also not aware of culture conditions that could stimulate stem cells that are uPAR+ and/or nestin+ to enter the cell cycle when the cells are within isolated tissue fragments encapsulated in the provisional matrix-mimicking hydrogel. Yang et al. (US 20130295060; PGPub reference 1 on 11/10/23 IDS) observed increased secretion of uPAR and nestin by cardiac progenitor cells grown in culture dishes in 1% fetal bovine serum (paragraphs 220-221) but did not detect stem cells or cell-cycle entry. Yang also did not perform three-dimensional culture of stem-cell-containing tissue fragments.1
Further, regarding claim 7, skilled artisans would have recognized that fibrin-based hydrogels would be impacted by the presence or absence of plasminogen activity, but there is nothing in the specification or the art to indicate that, for example, collagen hydrogels are degraded in the absence of PAIs. Specifically, regarding claim 7, if the hydrogel is merely collagen, then removing PAI from the culture medium would not cause matrix degradation because collagen is not sensitive to plasmin activity. (See Tuan et al., US 20040043026, reference C, showing that plasmin activates MMPs that in turn degrade collagen but not showing a direct effect of plasmin on collagen itself.) Claim 11 refers to increasing plasmin activity to degrade the hydrogel but does not require that, for example, the hydrogel contains fibrin (the target of plasmin in applicant’s exemplified system).
The as-filed application discloses a single type of “provisional matrix-mimicking hydrogel,” namely one constructed using fibrinogen and thrombin to create a fibrin-based hydrogel. (Paragraph 98.) The application contemplates the inclusion of other molecules (collagen, gelatin), but the presence of a fibrin base that is susceptible to plasmin activity is key to the “provisional” nature of the exemplified hydrogel. (See paragraphs 97-100, using fibrin for all exemplified provisional hydrogels.)
Claims 1 and 7 also require “3D culturing” the hydrogel “in a culture medium to which [PAI] is added” such that “tissue-resident uPAR+ and nestin+ stem cells . . . enter the cell cycle.” The plain interpretation of this step in the context of the entire method is that claims 1 and 7 require 3D culture conditions that result in the outcome recited in the preamble. The skilled artisan would therefore not have concluded that applicant possessed the cell as claim 14 sets it forth. The specification provides a single set of such conditions: culture with 45% DMAM, 45% Ham’s F12, 10% fetal bovine serum, 20ng/mL EGF, 2ng/mL bFGF, 10ng/mL IGF, and 10[Symbol font/0x6D]g/mL gentamycin, supplemented with 10-500[Symbol font/0x6D]g/mL transexamic acid or aminomethyl benzoic acid depending on the input tissue type, for 14 days with gentle shaking. (Paragraphs 106 and 107.)
Regarding claim 14, as discussed with respect to 35 U.S.C. 112(b), the skilled artisan would have understood that cells can be either “tissue-resident” or “isolated and cultured,” but not both. As such, the skilled artisan would not have concluded that applicant possessed cells that are simultaneously within a tissue and isolated from that tissue.
“For inventions in emerging and unpredictable technologies, or for inventions characterized by factors not reasonably predictable which are known to one of ordinary skill in the art, more evidence is required to show possession.” MPEP 2163(II)(A)(3)(a)(i). “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, reduction to drawings, 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 inventor was in possession of the claimed genus.” MPEP 2163(II)(A)(3)(a)(ii). Here, applicant claims a genus of hydrogels and culture conditions that cause uPAR+ and/or nestin+ stem cells to enter the cell cycle, but only one working embodiment is provided in the application. The skilled artisan would therefore not have concluded that applicant possessed the invention as it is claimed. The requirement for adequate written description has not been met.
Conclusion
No claims are allowed.
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/Lora E Barnhart Driscoll/Primary Examiner, Art Unit 3991
1 See also Yang et al., 2014, KR-10-2013-0124075 (cited on international search report and in written opinion of the international searching authority), at page 41 of copy provided with IDS. This Korean document by Yang appears to be identical to US 20130295060 and does not perform three-dimensional culture to yield uPAR+ and/or nestin+ stem cells that have entered the cell cycle.
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