DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, 18001462, US 20100322908, filed on or after March 16, 2013, WO 3032/250583, is being examined under the first inventor to file provisions of the AIA .
Priority
Claims 1-4, 7, 9, 13, 16-17, 20, 22, 24-25, 28, 30, 32 and 37 are pending.
This application claims Domestic Priority benefit as the national stage, under 35 USC 371, of PCT/IB2021/055055, filed 06/09/2021, and claims foreign priority benefit of AUSTRALIA 2020901931, filed 06/11/2020.
Claim Interpretation
The claims are drawn to method of culturing mesenchymal lineage precursor or stem cells in a three dimensional culture, the method comprising culturing a population of mesenchymal lineage precursor or stem cells on an adherent material in a cell culture medium, wherein the mesenchymal lineage precursor or stem cells are attached to the adherent material, wherein the adherent material is a porous microcarrier coated with a glycoprotein and, wherein the cell culture medium is animal serum free, and variations thereof.
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.
1. Claim(s) 1, 2, 3, 30, 32, 37 is/are rejected under 35 U.S.C. 103 as being unpatentable over Weiss, WO 2017132358, Published 3 Aug 2017, of record, PCT/US2017/015105; Birch, US 20160083690; and Simmons, US 20180037867, Publication Date Feb. 8, 2018, (of record IDS), Serial No. 15553115.
Weiss, WO 2017132358, Published 3 Aug 2017, of record, PCT/US2017/015105, teaches, throughout the publication and abstract, methods of culturing mesenchymal lineage precursor or stem cells in a three dimensional culture, and compositions thereof. Weiss, at, e.g., p. 6, lines 17-25; p. 7, lines 26-p. 8, line 26; p. 24, lines 18-24; p. 34, line 25-p. 35, line 8; reference claims 10, 11; describes expansion of umbilical cord-derived mesenchymal stem cells, (also called MSC), on microcarriers in xenogen-free culture medium comprising human platelet lysate. the method comprising culturing a population of mesenchymal lineage precursor or stem cells on an adherent material in a cell culture medium, wherein the mesenchymal lineage precursor or stem cells are attached to the adherent material, wherein the adherent material is a porous microcarrier coated with a glycoprotein and, wherein the cell culture medium is animal serum free. Weiss, teaches, at p. 24, line 3, p. 36, culturing cells in stirred tank bioreactors, as in claim 4; at p. 11, line 26, trypsin-EDTA to lift cells, as in claim 20; at p. 25, line 13.
Weiss does not teach degradable microcarriers. Weiss does not teach PDGF-BB, EGF2, and EGF.
Birch, 20160083690, throughout the publication and abstract and at para [0012]-[0013], teaches that the use of biodegradable, bioresorbable, polymer microcarriers that for cell implants because cells cultured on the biodegradable microcarriers can be implanted in-vivo, as an integral part of the tissue engineering process and where the biodegradable polymer is polycaprolactone (PCL). Birch, at para [0014], teaches porous microcarriers.
Birch states:
[0213] 106. The use of attachment substrates to coat biodegradable microcarriers, such that mesenchymal stem cells can attach and proliferate on these microcarriers in serum-containing or serum-free media.
[0214] a. Such biodegradable microcarriers include polycaprolactone microcarriers, coated with combinations of fibronectin, and/or poly-L-lysine, and/or vitronectin.
[0215] b. The use of multiple layers of such attachment substrates on the same microcarrier, which in combination may give better adhesion and/or proliferation of mesenchymal stem cells on the microcarrier.
[0216] c. Examples of such combinations include but are not limited to PCL coated with layers of fibronectin, then poly-L-lysine, then fibronectin.
[0217] d. The inclusion of vitronectin as attachment substrate to allow mesenchymal stem cell adhesion and/or growth on PCL microcarriers in serum-free media. One manifestation of this technology is PCL coated with fibronectin, and/or poly-L-lysine, and/or vitronectin.
[0218] e. The use of fibronectin, and/or poly-L-lysine, and/or vitronectin, to allow mesenchymal stem cell proliferation in static or agitated culture, where such attachment substrates allow cell adhesion and proliferation during agitation. Examples include the use of fibronectin-PLL-fibronectin coatings to allow mesenchymal stem cell adhesion and growth in serum-containing media, and the use of fibronectin-PLL-vitronectin to allow mesenchymal stem cell adhesion and growth in serum-free media.
Birch at [0213]-[0218].
The prior art publication of Simmons, US 20180037867, Publication Date Feb. 8, 2018, Serial No. 15553115, throughout the publication and abstract, describe cell culture methods for mesenchymal stem cells. Simmons, at p. 1, para [0006]-[0013], pp. 8-9, para [0016], teaches PDGF-BB and FGF2 synergistically promote mesenchymal cell proliferation. Simmons at, e.g., para [0014], Fig.s 5-10, para [0111], and throughout the publication, teaches that EGF acts synergistically with other growth factors to promote MSC proliferation. Simmons at p. 3, para [14], teaches medium that maintain the stem cells in an undifferentiated state, as in instant claim 37.
It would have been prima facie obvious before the application was filed for one of ordinary skill in the art to have combined degradable microcarriers, as taught by Birch, and PDGF-BB and FGF2, and EGF, as taught by Simmons, in the methods of culturing mesenchymal lineage precursor or stem cells in a three dimensional culture, as taught by Weiss.
One of ordinary skill in the art would have been motivated to have combined use of biodegradable, bioresorbable, polymer microcarriers carrying cultured cells because cells cultured on the biodegradable microcarriers could be implanted in-vivo, as an integral part of the tissue engineering process, in the mesenchymal lineage stem cells methods of Weiss. One of ordinary skill in the art would have been motivated to have combined PDGF-BB and FGF2 in methods of culturing mesenchymal lineage precursor or stem cells in a three dimensional culture to synergistically promote mesenchymal cell proliferation, as taught by Simmons.
2. Claim(s) 7, 9, is/are rejected under 35 U.S.C. 103 as being unpatentable over Weiss, WO 2017132358, Published 3 Aug 2017, of record, PCT/US2017/015105; Birch, US 20160083690; and Simmons, US 20180037867, Publication Date Feb. 8, 2018, (of record IDS), Serial No. 15553115 as applied to claims 1, 2, 3, 30, 32, 37 above, and further in view of Kang, US 20170216498, Publication Date Aug. 3, 2017, (of record IDS), Serial No. 15488336,.
The prior art publication of Weiss, WO 2017132358, Published 3 Aug 2017, of record, PCT/US2017/015105; Birch, US 20160083690; and Simmons, US 20180037867, Publication Date Feb. 8, 2018, (of record IDS), Serial No. 15553115, are relied upon as above.
Weiss does not teach where the microcarrier has a degradable core and does not teach microcarriers with macropores.
Kang, US 20170216498, [0012]-[0020] [0043] pp. 24-25, [0208], teach polymeric biodegradable cores; and mesenchymal stem cells on a biodegradable polymeric core material and biodegradable shell (“bio-ink”). Fig. 1A-1F. [0093] micropores or microchannels. Kang at para [0018] teaches biodegradable polymeric core material that is collagen. Kang, at para [0146], [0284], teaches micropores, such as with a size of more than about 50 nm). Kang at para [0281]-[0309], [0285], teaches cells that are stem cells for use in microcarrier culture, and stem cells that are mesenchymal stem cells, including stem cells that are derived from umbilical cord blood.
It would have been prima facie obvious before the claimed invention was filed for one of ordinary skill in the art to have used microcarriers comprising biodegradable cores, as taught by Kang, in the methods of culturing mesenchymal lineage precursor or stem cells in a three dimensional culture, as taught by Weiss.
One of ordinary skill in the art would have been motivated to have used microcarriers comprising biodegradable cores, as taught by Kang, in the methods of culturing mesenchymal lineage precursor or stem cells in a three dimensional culture, as taught by Weiss, to promote degradation of shells and formation of an integrated and functional tissue or tissue progenitor before transplantation into a subject, as taught and suggested by Kang at para [0093].
3. Claim(s) 13, 22, 28 is/are rejected under 35 U.S.C. 103 as being unpatentable over the prior art publications of Weiss, WO 2017132358, Published 3 Aug 2017, of record, PCT/US2017/015105; Birch, US 20160083690; and Simmons, US 20180037867, Publication Date Feb. 8, 2018, (of record IDS), Serial No. 15553115, and Kang, US 20170216498, Publication Date Aug. 3, 2017, (of record IDS),Serial No. 15488336, and Masters, J.R.W. (ed.), in Animal Cell Culture, Third Edition, (Published 2000), (of record in IDS filed 1/17/2025, citation NPL1).
The prior art publication of Weiss, WO 2017132358, Published 3 Aug 2017, of record, PCT/US2017/015105; Birch, US 20160083690; and Simmons, US 20180037867, Publication Date Feb. 8, 2018, (of record IDS), Serial No. 15553115, and Kang, US 20170216498, Publication Date Aug. 3, 2017, (of record IDS),Serial No. 15488336, are relied upon as above.
Weiss does not teach where the microcarrier is porous, the culture medium comprises 0.5 g/L to 5 g/L, microporous or macroporous microcarriers, wherein about 70% of medium is replaced every 24 hours of culture, where the mesenchymal stem cell (MSC) are seeded at between 5,000 and 20,000 cells/ml, mesenchymal stem cell are cultured in three dimensional culture for at least six days.
Kang, US 20170216498, [0012]-[0020] [0043] pp. 24-25, [0208], teach polymeric biodegradable cores; p. , mesenchymal stem cell, cell on a core biodegradable polymeric core material and biodegradable shell (“bio-ink”). Fig. 1A-1F. [0093] micropores or microchannels. Kang at para [0018] teaches biodegradable polymeric core material that is collagen. Kang, at para [0146], [0284], teaches micropores, such as with a size of more than about 50 nm). Kang at para [0281]-[0309], [0285], teaches cells that are stem cells, and stem cells that are mesenchymal stem cells, including stem cells that are derived from umbilical cord blood.
J.R.W. Masters (ed.), in Animal Cell Culture, Third Edition, (Published 2000), (of record in NPL1, IDS filed 1/17/2025), at p. 14, Fig.1, describes a typical growth curve, i.e., yield of cells from culture, as a function of days for a cell culture seeded at 20,000 cells /ml, as in claim 28, and cultures that at least 6 days. Masters, at pp. 32-48, teaches cell monolayer culture, which reads upon 2D culture of cells, and p. 33, notes the ease of change and control of culture medium that monolayer culture affords.
Masters discusses microcarrier concentration:
The author's experience has largely been with dextran-based microcarriers (Cytodex and Dormacell) and much of the following discussion is based on these products. The choice of this microcarrier was based on a preference for a dried product which could be accurately weighed and then prepared in situ, and the fact that with a density of only 1.03 g/ml this product could be used at concentrations of up to 15 g/litre (90000 cm2/litre).
Masters, at pp. 41-42, bridging paragraph. Master further discusses concentration in the use of Cytodex as microcarriers, stating:
Protocol 3, Microcarrier culture
1. Add complete medium to spinner flask (200 ml in a 1 litre flask, gas with 5% CO, and allow to equilibrate.
2. Decant PBS from sterilized stock solution of Cytodex-3 and replace with growth medium (1g to 30-50 ml). Add Cytodex-3 to spinner vessel to give a final concentration of 2 g/litre (1-3 g/litre).
Masters, at pp. 41-42, bridging paragraph. Thus, Masters teaches a microcarrier concentration of 2 g/L, as in claim 13.
Masters, at pp. 62-66, teaches porous carriers for use as microcarriers, with a pore size of 20-40 micrometers.
Masters, at p. 127, para 3, teaches that for many tumor cells types, 3D spheroid cultures two-thirds of the medium has to be refreshed every 24-48 hours
It would have been prima facie obvious before the claimed invention was filed for one of ordinary skill in the art to have used porous microcarrier and wherein the culture medium comprises 0.5 g/L to 5 g/L in 3D cultures, macroporous microcarriers, wherein about 70% of medium is replaced every 24 hours of culture, wherein the mesenchymal stem cell (MSC) are seeded at between 5,000 and 20,000 cells/ml, and wherein mesenchymal stem cell are cultured in three dimensional culture for at least six days, as taught by Kang and Masters, in the method of culturing mesenchymal lineage precursor or stem cells, as further taught by Weiss.
One of ordinary skill in the art would have been motivated to have combined into the methods of Weiss, porous microcarriers, wherein the culture medium comprises 0.5 g/L to 5 g/L in 3D cultures, macroporous microcarriers, wherein about 70% of medium is replaced every 24 hours of culture, wherein the mesenchymal stem cell (MSC) are seeded at between 5,000 and 20,000 cells/ml, and wherein mesenchymal stem cell are cultured in three dimensional culture for at least six days, because these claim limitations are taught and suggested in the art, and one of ordinary skill in the art would naturally optimize by routine experiment to conditions best suited to the MSC systems of Weiss.
MPEP I. OVERLAPPING, APPROACHING, AND SIMILAR RANGES, AMOUNTS, AND PROPORTIONS, considers that in the case where the claimed ranges overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990)
Furthermore,
MPEP II.A. Optimization within prior art conditions or through routine experimentation.
Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.
" In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955) (
In regards to 14, pp. 14-15, Fig.1, describes a typical growth curve, i.e., yield of cells from culture, as a function of days for a cell culture seeded at 20,000 cells /ml, as in claim 28, and cultures that are at least 6 days. As was stated in the prior art of Masters, at p. 12,
It is an important element of quality control to be able to demonstrate that the same seeding concentration will yield a reproducible number of cells at subculture, carried out after a consistent time interval, without necessarily performing a growth curve each time.
Masters at p. 12.
Thus, it would have been routine for one of ordinary skill in the art to characterized cell yield, seed number, and days of culture, and to optimize these parameters for particular cell culture systems.
In regards to the term “about 70%,” the specification at para [52], defines the term “about as plus or minus 10%, so that the prior art teaching of Masters at p. 121, of replacement of 2/3 of medium reads upon claim 17.
4. Claim(s) 24, 25 is/are rejected under 35 U.S.C. 103 as being unpatentable Birch, US 20160083690; and Simmons, US 20180037867, Publication Date Feb. 8, 2018, (of record IDS), Serial No. 15553115, and Kang, US 20170216498, Publication Date Aug. 3, 2017, (of record IDS),Serial No. 15488336, and Masters, J.R.W. (ed.), in Animal Cell Culture, Third Edition, (Published 2000), (of record in IDS filed 1/17/2025, citation NPL1), as applied to claims 1, 2, 3, 13, 22, 28, 30, 32, 37 above, and further in view of Itescu, WO 2018/202853, published 08 Nov. 2018, of record, IDS), (Serial No. 16607293, which is a 371 of PCT/EP2018/061503, filed 5/4/2018), and Masters, J.R.W. (ed.), in Animal Cell Culture, Third Edition, (Published 2000), (of record in IDS filed 1/17/2025, citation NPL1).
Birch, US 20160083690; and Simmons, US 20180037867, Publication Date Feb. 8, 2018, (of record IDS), Serial No. 15553115, and Kang, US 20170216498, Publication Date Aug. 3, 2017, (of record IDS),Serial No. 15488336, and Masters, J.R.W. (ed.), in Animal Cell Culture, Third Edition, (Published 2000), (of record in IDS filed 1/17/2025, citation NPL1) are relied upon, as above, but do not teach master cell bank.
Itescu, WO 2018/202853, teaches at p. 19, para [0152], Serial No. 16607293, which is a 371 of PCT/EP2018/061503, filed 5/4/2018.
[0152] In a preferred embodiment of the invention, the mesenchymal lineage precursor or stem cells are obtained from a master cell bank derived from mesenchymal lineage precursor or stem cells enriched from the bone marrow of healthy volunteers. The use of mesenchymal lineage precursor or stem cells derived from such a source is particularly advantageous for subjects who do not have an appropriate family member available who can serve as the mesenchymal lineage precursor or stem cell donor, or are in need of immediate treatment and are at high risk of relapse, disease-related decline or death, during the time it takes to generate mesenchymal lineage precursor or stem cells.
Itescu, WO 2018/202853, at p. 19, para [0152], emphasis added.
Furthermore, J.R.W. Masters (ed.), in Animal Cell Culture, Third Edition, (Published 2000), (of record in NPL1, IDS filed 1/17/2025), at p. 14, Fig.1, describes a typical growth curve, i.e., yield of cells from culture, as a function of days for a cell culture seeded at 20,000 cells /ml, as in claim 28, and cultures that at least 6 days. Masters, at pp. 32-48, teaches cell monolayer culture, which reads upon 2D culture of cells, and p. 33, notes the ease of change and control of culture medium that monolayer culture affords.
Masters discusses microcarrier concentration:
The author's experience has largely been with dextran-based microcarriers (Cytodex and Dormacell) and much of the following discussion is based on these products. The choice of this microcarrier was based on a preference for a dried product which could be accurately weighed and then prepared in situ, and the fact that with a density of only 1.03 g/ml this product could be used at concentrations of up to 15 g/litre (90000 cm2/litre).
Masters, at pp. 41-42, bridging paragraph. Master further discusses concentration in the use of Cytodex as microcarriers, stating:
Protocol 3, Microcarrier culture
1. Add complete medium to spinner flask (200 ml in a 1 litre flask, gas with 5% CO, and allow to equilibrate.
2. Decant PBS from sterilized stock solution of Cytodex-3 and replace with growth medium (1g to 30-50 ml). Add Cytodex-3 to spinner vessel to give a final concentration of 2 g/litre (1-3 g/litre).
Masters, at pp. 41-42, bridging paragraph. Thus, Masters teaches a microcarrier concentration of 2 g/L, as in claim 13.
Masters, at pp. 62-66, teaches porous carriers for use as microcarriers, with a pore size of 20-40 micrometers.
Masters, at p. 127, para 3, teaches that for many tumor cells types, 3D spheroid cultures two-thirds of the medium has to be refreshed every 24-48 hours. Instant claim 17 recites “70%”. The instant Specification, describes, e.g., at para [140]:
It would have been prima facie obvious before the claimed invention was filed for one of ordinary skill in the art to have used master cell bank, as taught by Itescu and 2D culture, i.e. monolayer culture, as taught by Weiss and Masters, respectively, in the method of culturing mesenchymal lineage precursor or stem cells, as further taught by Weiss.
Response to Amendment
The rejection under 35 U.S.C. 102 over Weiss has been withdrawn over applicant’s amendments to the claims and arguments. Applicant added the limitation of degradable microcarrier to claim 1, but removed the claim 1 limitation that the microcarrier be porous. Thus the “degradable core” of now-withdrawn claim 6 and which limited a microcarrier of claim 1 that was porous, (see, claims entered 6/6/2023), had a narrower scope than the microcarrier of current claim 1, which is broader, because a porous core microcarrier is no longer required in current claim 1.
The Reply to the previous action argues that the materials taught by the prior art for the microcarriers are not porous, but both Birch and Kang describe porous microcarriers. The Reply argues that there would be motivation to apply the teaching of Simmons to 3D culture, because Example 2/Figure 3 provides evidence that “culture media/conditions optimized in 2D will not necessarily translate to 3D systems,” is not persuasive because there is not a presentation of objective evidence of how the practitioner would interpret the results, but instead relies on the opinion of counsel.
It is noted by both the previously cited reference of Kang and new reference of Birch, teach porous microcarriers. The Reply argues that the teaching of Kang is outside of normal culturing conditions and that there is no suggestion that bio-blocks could be used in a large scale bioreactor. The Reply appears to argue limitations not found in the claims. The Reply argues that Kang is not analogous art. Birch, at para [0004], describes three-dimensional bioreactors as highly scalable technology. Birch at para [0012] teaches the use of microcarriers for cell implantation. Aside from the newly cited reference of Birch, all references, including Kang, that were cited in the first action, were of record, and cited in applicant’s first IDS.
The Reply argues that the prior art reference of Masters has been “cherry picked” to meet the limitations of claims. This appears to be an argument for impermissible hind-sight reasoning, but as the rejections take into account only knowledge which was within the level of ordinary skill in the art at the time the claimed invention was made and does not include knowledge gleaned only from applicant’s disclosure, such a reconstruction is proper.
The Reply argues that the practitioner would not be motivated to combine the master cell bank, as taught by Itescu, because Itescu does not employ 3D culture methods. However, Birch, at para [0004], describes three-dimensional bioreactors as highly scalable technology. Birch at para [0012] teaches the use of microcarriers for cell implantation. It is not unreasonable that the practitioner, in seeking to grow cells, would obtain cells from a master cell bank.
Conclusion
1. All pending claims 1-4, 7, 9, 13, 16-17, 20, 22, 24-25, 28, 30, 32 and 37 are rejected
2. 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 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.
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MARK L. SHIBUYA
Primary Patent Examiner
Art Unit 1631
/MARK L SHIBUYA/Primary Patent Examiner, Art Unit 1631