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 .
Election/Restrictions
Applicant’s election without traverse of Group I (claims 1-9, 12-21 and newly added claim 35) in the reply filed on Dec. 18, 2025 is acknowledged. Claim 22 is withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim.
Claims 1-9, 12-21 and newly added claim 35 drawn to the elected method are examined below. Claim 22 is withdrawn.
Priority
The application claims priority to provisional applications 63/063942, filed August 10, 2020; as such the earliest possible priority date is August 10, 2020.
Information Disclosure Statement
The information disclosure statements filed April 26, 2023 and Dec. 24, 2024 are in compliance with the provisions of 37 CFR 1.97. Accordingly, the IDSs have been considered by the examiner.
Claim Rejections - 35 USC § 112
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 1-9, 12-21 and 35 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, because the specification, while being enabling for a method of expanding and maintaining human stem cells in an undifferentiated, pluripotent state by simultaneously combining human stem cells, a human laminin 511 E8 fragment and a microcarrier pre-coated with a synthetic surface containing RGD peptides immobilized on acrylate coating or a microcarrier that has been pre-treated to improve adhesion in a growth media to form a suspendable expansion complex and culturing the suspendable expansion complex,
does not reasonably provide enablement for a method of expanding and maintaining human stem cells in an undifferentiated, pluripotent state by simultaneously combining human stem cells, any extracellular matrix component (ECM) and any microcarrier in a growth media to form a suspendable expansion complex and culturing the suspendable expansion complex. The specification does not enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to use the invention commensurate in scope with these claims.
To be enabling, the specification of the patent application must teach those skilled in the art how to make and use the full scope of the claimed invention without undue experimentation. In re Wright, 999 F.2d 1557, 1561 (Fed. Cir. 1993). Explaining what is meant by "undue experimentation," the Federal Circuit has stated that:
The test is not merely quantitative, since a considerable amount of experimentation is permissible, if it is merely routine, or if the specification in question provides a reasonable amount of guidance with respect to the direction in which experimentation should proceed to enable the determination of how to practice a desired embodiment of the claimed invention.
PPG V. Guardian, 75 F.3d 1558, 1564 (Fed. Cir. 1996). 1
1 As pointed out by the court in In re Angstadt, 537 F.2d 498 at 504 (CCPA 1976), the key word is "undue", not "experimentation."
The factors that may be considered in determining whether a disclosure would require undue experimentation are set forth by In re Wands, 8 USPQ2d 1400 (CAFC 1988) at 1404 wherein, citing Ex parte Forman, 230 USPQ 546 (Bd. Apls. 1986) at 547 the court recited eight factors:
1) the nature of the invention,
2) the breadth of the claims,
3) the state of the prior art,
4) the predictability or unpredictability of the art,
5) the relative skill of those in the art,
6) the amount of direction or guidance provided,
7) the presence or absence of working examples,
8) the quantity of experimentation necessary
These factors are always applied against the background understanding that scope of enablement varies inversely with the degree of unpredictability involved. In re Fisher, 57 CCPA 1099, 1108,427 F.2d 833,839, 166 USPQ 18, 24 (1970). Keeping that in mind, the Wands factors are relevant here for the following reasons:
1) The nature of the invention and 2) the breadth of the claims
The claims are drawn to a method expanding and maintaining human stem cells in an undifferentiated, pluripotent state by simultaneously combining human stem cells, an extracellular matrix component (ECM) and a microcarrier in a growth media to form a suspendable expansion complex and culturing the suspendable expansion complex to expand and maintain human, undifferentiated, pluripotent state stem cells. Thus, the claims taken together with the specification imply that Applicant is claiming that any extracellular matrix component (ECM) and any microcarrier in a growth media with human stem cells will form a suspendable expansion complex that can be cultured, resulting in the expansion and maintenance of an undifferentiated, pluripotent state.
3) the state of the art, 4) unpredictability of the art and 5) the relative skill of those in the art
The relative skill of those in the art is high, generally that of a PhD in cell biology or a related field or a research physician.
That factor is outweighed, however, by the unpredictable nature of the art.
As disclosed by applicants, the current state of the art is, generally, to coat microcarriers before cell inoculation, during a pre-coating step, which has a variable time range. For example, Oh et al. (WO 2009/116951, cited in IDS filed on Dec. 24, 2024) teach undifferentiated human embryonic stem cells (hESCs) can be expanded on ECM (Matrigel, hyaluronic acid or laminin) coated microcarriers using 3-dimensional suspension culture. (para. bridging pgs. 117-118). Silva et al. (Stem Cell Transl Med, 2015) teach large scale expansion of hESCs on polystyrene microcarriers coated with Synthemax II and hydrogel in stirred-tank bioreactors, finding a vitronectin-coated surface was the most effective for expansion of hESCs in 2D culture, while human E-cadherin, and a substrate composed of mainly fibronectin and albumin did not perform well. (p. 734, 2nd para.; Fig. 2B).
Lam et al. (Biochem Biophys Res Comm, 2016) teach that microcarriers (MC) can be used to overcome the cost and scalability of human pluripotent stem cell expansion and differentiation, enabling expansion of cells as the cell-MC aggregate. (Abstract). Lam et al. teach that the properties of MCs, such as shape, size, surface charge and coating, “significantly affect cell attachment, growth rates and cell pluripotency…”. (pg. 766, 4.1 “Microcarriers and its coatings”). Lam et al. further teaches
Several ECM matrices were reported to be used for MC coating. Initially undefined Matrigel and serum-containing media were used. In later stages various defined human ECM proteins and serum-free medium systems have been developed. ECM substrates (such as laminin, vitronectin, fibronectin, heparin and hyaluronic acid) and serum-free media (such as StemPro and MTeSR1) were tested achieving different levels of cell expansion and differentiation.
Our group has reported that laminin and vitronectin can be used as MC coatings achieving 1.2 – 1.5 x 106 cells/ml hESC density (over 20 passages) in static MC culture. In switching to stirred culture, coating of a combination of cation poly-L-lysine (PLL) and ECM proteins (in particular laminin-111) is needed to ensure cell growth. A recent study reported that due to the high affinity of human laminin-521 it can be used as a single coating of polystyrene MC achieving efficient cell attachment, spreading and growth of hPSC in agitated cultures without additional positive charge.
(pg. 766, 4.1 “Microcarriers and its coatings,” 1st para., citations omitted, emphasis added).
Miyazaki et al. teach 2-D adhesion culture of human pluripotent stem cells using laminin fragments placed in media with the cell suspension during cell passaging using culture vessels that were not pre-coated. (Abstract).
Thus, the person of ordinary skill in this art has an understanding that 2D culture can be carried out with different ECM coating on the vessel; that microcarrier can be coated with ECMs for expansion or differentiation of stem cells in 3D culture, but which microcarriers will work with which ECMs and result in expansion or differentiation is unpredictable; and that 2D culture with an un-coated vessel and specific laminin fragments added to the cell culture medium during passaging resulting in human pluripotent stem cell expansion. That person does not have an understanding that combining human stem cells, any extracellular matrix component (ECM) and any microcarrier in a growth media to form a suspendable expansion complex and culturing the suspendable expansion complex will result in stem cell expansion and growth with the stem cells remaining in their undifferentiated, pluripotent state. The understanding the art provides does not readily extend from either ECMs successfully used in coating culture vessels for 2D culture or ECMs successfully used in coating microcarriers to support the premise that adding any extracellular matrix component (ECM) and any microcarrier in a growth media to human stem cells will successfully result in expansion and maintenance of undifferentiated, pluripotent human stem cells. As Lam et al. explain, in the area of selecting ECM for coating of microcarriers, “ECM substrates (such as laminin, vitronectin, fibronectin, heparin and hyaluronic acid) and serum-free media (such as StemPro and MTeSR1) were tested achieving different levels of cell expansion and differentiation.” (pg. 766, 4.1 “Microcarriers and its coatings,” 1st para., citations omitted). There is no way for one skill in the art to know, a priori, which ECM and which microcarrier place in a suspension with growth media and human stem cells will result in expanding and maintained undifferentiated, pluripotent stem cells with a reasonable expectation of results. Thus, the state of the prior art does not support the broad
scope of the above claims.
6) the amount of direction and guidance provided and 7) the presence
and absence of working examples
While the specification discloses that different ECMs have been used in conjunction with specific MCs to grow human pluripotent stem cells (see Table 4), it is clear from this table that in the microcarrier coated hESC expansion area, the person of ordinary skill in the art does not expect any ECM to work with any MC; rather specific ECMs have been tried with specific MC with varying results on expansion and maintenance of undifferentiated, pluripotent stem cells. Furthermore, the specification does not provide support for the use of any ECM with any microcarrier in the claimed invention; rather applicants say that different ECMs have successfully been used to coat a different microcarriers for expansion using coated MCs. (pg. 9-12, Example 1). The specification offers a single working example - HESC expansion with laminin 511 E8 fragment added to a medium and combined with a specific microcarriers (Synthemax® II synthetic surface containing RGD peptides immobilized on acrylate coating or Corning® Enhanced Attachment Microcarriers, which are surface treated to promote cell attachment.). (Table 9, para. [0158]). Furthermore, the specification states “others [MCs] were tested in the POC [proof of concept] study and failed…”. (para. [0158]). Thus, it appears that only one ECM (laminin 511 E8 fragment) was tested and it only worked when combined with two, specific MCS (Synthemax® II synthetic surface containing RGD peptides immobilized on acrylate coating or Corning® Enhanced Attachment Microcarriers, which are surface treated to promote cell attachment) and failed to work with others. The specification does not explain how any other ECMs will work, with these microcarriers or other microcarriers, the parameters to consider when selecting a specific ECM and MC or which MCs did not work with the laminin 511 E8 fragment, the only successful ECM used in the POC study.
8) The quantity of experimentation necessary
Because of the known unpredictability of the art (as discussed supra) and
in the absence of experimental evidence commensurate in scope with the claims,
the skilled artisan would not accept the assertion that forming a suspendable expansion complex with human stem cells and any extracellular matrix component (ECM) and any microcarrier in a growth media and culturing the suspendable expansion complex will result in expanding and maintaining the human stem cells in a pluripotent, undifferentiated state.
Genentech Inc. VS. Nova Nordisk states, "[A] patent is not a hunting license. It is not a reward for a search but a compensation for its successful conclusion and 'patent protection' is granted in return for an enabling disclosure of an invention, not for vague intimations of general ideas that may or may not be workable." (42 USPQ 2d 1001, Fed. Circuit 1997).
To practice the invention of the instant claims required undue experimentation due to unpredictability in matching MC and ECMs even when preparing coated MCs and even more so when adding the ECM and MC to a cell suspension. As Lam et al. explain, in the area of selecting ECM for coating of microcarriers, “ECM substrates (such as laminin, vitronectin, fibronectin, heparin and hyaluronic acid) and serum-free media (such as StemPro and MTeSR1) were tested achieving different levels of cell expansion and differentiation.” (pg. 766, 4.1 “Microcarriers and its coatings,” 1st para., citations omitted). To practice the invention of the instant claims requires undue experimentation due to the unpredictability of matching MCs with ECMs that result in successful culture of cells and successful maintenance of pluripotency. This unpredictability is still present in the more established ECM-coated MC art. It would be even greater in the area of using an ECM in the cell culture media instead of coating it on an MC or a culture vessel. The amount of experimentation required in order to practice the claimed invention is extremely large due to the unpredictability of the MC, the ECM and what effect the resulting combination would have on a stem cell (expansion, statis, differentiation, death). To
determine which additional combinations of ECMs and MCs would function in the claimed manner would require inventive effort and extensive experimental burden. In light of the above discussion, the instant claims do not comply with the enablement requirement of 35 U.S.C. § 112, first paragraph, since to practice the claimed invention a person of ordinary skill in the art would have to engage in undue experimentation, with no assurance of success.
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 1-9, 12-21 and 35 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.
The term “undifferentiated, pluripotent state” in claim 1 is a relative term which renders the claim indefinite. The term is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. That is, the person of ordinary skill would not know exactly how “undifferentiated and pluripotent” the state of the stem cells is required to be.
Dependent claims 2-9, 12-21 and 35 do not resolve this deficiency and are rejected on that basis.
Claims 19-21 are rejected as they each recite “wherein the undifferentiated cells express at least about x % of [pluipotency biomarkers] SSEA-5, TRA-1-60, Oct-4 and/or Nanog”. This is indefinite, as it is unclear how a cell can express at 70% of a biomarker. The convention in the art is to recite, for example, that 80% of the stem cells express a certain biomarker.
Conclusion
No claims are allowed. The following art is closest to the subject matter that applicants are enabled for – a method of expanding and maintaining human stem cells in an undifferentiated, pluripotent state by simultaneously combining human stem cells, a human laminin 511 E8 fragment and a microcarrier pre-coated with a synthetic surface containing RGD peptides immobilized on acrylate coating or a microcarrier that has been pre-treated to improve adhesion in a growth media to form a suspendable expansion complex and culturing the suspendable expansion complex:
Miyazaki et al. (Scientific Reports, 2017, cited in IDS filed on Dec. 24, 2024) teach that laminin fragments (iMatrix™ 511, which is a laminin 511 E8 fragment and laminin-521) added to culture medium, rather than pre-coating it on a substrate, supports cell adhesion in 2D culture. Miyazaki et al. teach that cells in media with uncoated laminin fragments grew well (without cell detachment) and maintained pluripotency during subculture. Miyazaki et al. further teach that the uncoated laminin provided this benefit at lower concentration than that required when pre-coating a substrate with it.
Oh et al. (WO 2009/116951, cited in IDS filed on Dec. 24, 2024) teach that laminin coated on DE53 (positively charged, cellulose) or Cytodex™3 microcarriers (a thin, denatured collagen layer coupled to a cross-linked dextran matrix) were able to support expansion of undifferentiated, pluripotent to at least passage 5. (Fig. 166, pgs. 53-54, pg. 151).
There is no reasonable expectation of success that the combination taught by Oh et al. (laminin coated on DE53 or Cytodex™3 microcarriers) would work in the teachings provided by Miyazaki et al. of using laminin fragments. As the inventors themselves found that microcarriers other than the two they used (which are not those taught by Oh et al.), failed when tested in a proof of concept study. (specification, para. [0158]).
Any inquiry concerning this communication or earlier communications from the examiner should be directed to TERESA E KNIGHT whose telephone number is (571)272-2840. The examiner can normally be reached Monday-Friday 9-4.
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/TERESA E KNIGHT/Primary Examiner, Art Unit 1634