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 Status
1. The amendment filed 02/03/2026 has been entered. Claims 1 – 5, 7, 8, 11, 12, and 19 – 23 remain pending.
Election/Restrictions
2. Applicant’s election without traverse of Group I in the reply filed on 11/17/2023 is acknowledged.
3. Claims 11, 12, and 19 – 22 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim.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 11/17/2023.
4. Claims 1 – 5, 7, 8, and 23 are under consideration.
Priority
5. This application claims priority to U.S. provisional application 63/254,830 filed on 10/12/2021.
Withdrawn Claim Objections
6. The objection to claim 1 is withdrawn in view of Applicant’s amendment to the claim.
Claim Interpretation
7. Claim 1 is interpreted as a sequential method where hESCs or iPS cells are cultured in a first cell culture media and cells obtained from said first cell culture media are cultured in a second cell culture media and cells obtained from said second cell culture media are cultured in a third cell culture media instead of culturing hESCs or iPS cells in a first cell culture media and separately in a second cell culture media.
8. “Small hepatocyte progenitor cells” of claim 1 are interpreted as mature hepatocyte precursor cells with a small round morphology with clear nuclei resembling mature adulty hepatocytes but smaller in size as defined in Applicant’s specification at page 5, paragraph 00028.
Maintained Claim Rejections
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.
9. Claims 1 – 5, 7 – 8, and 23 remain rejected under 35 U.S.C. 103 as being unpatentable over Deng (US-20120190059-A1, Filed 07/23/2009; Published 07/26/2012; previously cited), hereinafter Deng in view of Ang (Ang LT, et. al. Cell Rep. 2018 Feb 20;22(8):2190-2205; previously cited), hereinafter Ang as evidenced by Ying (Ying, Mingyao, et al. Oncogene 30.31 (2011): 3454-3467; previously cited), hereinafter Ying and Wang (Wang T, et. al. Dev Growth Differ. 2012 Jun;54(5):605-17; previously cited), hereinafter Wang in view of in view of Sengupta (Sengupta S, et.al. Curr Res Toxicol. 2020 Aug 26;1:70-84; previously cited), hereinafter Sengupta which is a citation made of record on IDS filed 03/22/2023. Although maintained, the rejection has been revised in view of Applicant’s amendment to claim 1.
Regarding claims 1 and 7, Deng teaches a method of generating hepatic progenitors from hESCs or iPS cells comprising culturing hESCs or iPS cells on mouse embryonic fibroblast (MEF) feeder layer in a culture media comprising Activin A (“culturing in a first cell culture media human embryonic stem cells or induced pluripotent stem cells (iPS cells) in the presence of embryonic fibroblasts in a culture medium that comprises Activin A” of claim 1 and “mouse embryonic fibroblasts” of claim 7) to produce definitive endoderm (DE) (page 12, 0245; page 11, 0228 – 0231). Deng teaches initiation of hepatocyte differentiation by culturing DE in a media comprising a bone morphogenetic protein and a fibroblast growth factor (“bone morphogenetic protein” and “fibroblast growth factor” of claim 1) (page 12, 0246; page 11, 0232 – 0234). Deng teaches proliferation of differentiated cells in media comprising HGF (page 12, 0237 and 0247; page 11, 0235 – 0236). Deng teaches maturing hepatic progenitors by culturing in media comprising Oncostatin M and dexamethasone (“dexamethasone” and “Oncostatin M” of claim 1)(page 12, 0238 – 0240 and 0248). Deng does not teach TGF-beta inhibitor and a notch pathway inhibitor, or a cell population comprising small hepatocyte progenitor cells that are CD44+ of claim 1.
Regarding claim 2, Deng teaches the bone morphogenetic protein can be bone morphogenetic protein 2 (page 2, 0018).
Regarding claim 3, Deng teaches the fibroblast growth factor can be fibroblast growth factor 4 (page 2, 0018).
Regarding claim 8, Deng teaches culturing the cells with activin A for 3 days, culturing the cells in the FGF/BMP media for 4 days, and culturing the cells for 6 days and culturing the cells in dexamethasone and Oncostatin M for 5 days (page 12, 0244 – 0248).
Deng does not teach TGF-beta inhibitor and a notch pathway inhibitor, or a cell population comprising small hepatocyte progenitor cells that are CD44+ of claim 1 or the notch pathway inhibitor is DAPT of claim 5. However, Deng teaches the hepatocyte progenitors produced by the method show clear staining of nuclei and are capable of differentiating into hepatocytes (Figure 16 and 21; page 10, 0180 and 0188; page 16, 0330; page 17, 0344). Deng teaches hESCs can be used for studying the mechanism of cell lineage determination during development or in the cell transplantation for all kinds of degenerative diseases (page 1, 0005). Deng teaches hepatic progenitor cells can be obtained only by direct isolation from liver for now, and the shortness of early-stage human embryos dramatically limits the investigation in this field (page 1, 0007). Deng teaches the use of the hepatocytes obtained by the method for the preparation of artificial livers or testing of drug toxicity or drug screening (page 2, 0023; page 4, 0055; page 5, 0074 – 0075). Deng teaches the liver plays an important role in metabolism in the human body and possesses many critical functions including glycogen synthesis and detoxification (page 1, 0005). Deng teaches the differentiated cells express AFP, Alb, CD18, AAT, and CYP3A4 (page 13, 0268). Deng teaches the differentiated cells had glycogen synthesis and storage function, urea synthesis function, albumin secretion function, and drug-induced P450 enzyme activity similar to that of hepatocytes indicating that the method induced differentiation of hESC and iPS cells to hepatocytes (page 13, 0270, 0272, 0274, 0277).
Regarding TGF-beta inhibitor and notch inhibitor of claim 1, Ang teaches an 18-day method of producing hepatocytes from human pluripotent stem cells (hPSCs) outlined in Figure 7 where after formation of DE, cells are cultured in media comprising retinoic acid (“notch pathway inhibitor”), FGF, BMP, and a TGF-beta inhibitor (“TGF-beta inhibitor”) to form posterior foregut (page 2195, left col. para. 2 – 4 and right col. para. 1; Supplemental Information page 1, para. 2). Ang teaches the prevailing view to generate hepatocyte-like cells from hPSCs is roughly divided into three stages where current protocols start with (1) Activin/TGF-beta to induce endoderm; followed by (2) BMP and FGF to specify liver progenitors; and finally (3) hepatocyte growth factor, Oncostatin M, and dexamethasone (page 2193, left col. para. 3). Retinoic acid acts as a notch inhibitor where retinoic acid downregulates expression of CD133 and Hes family members as evidenced by Ying (Abstract; page 3457, left col. last para; page 3460, right col. last para.; page 3460, right col. last para.; Table 2b; page 3463, left col. last para. and right col. para. 1 – 3; page 3464, left col. last para. and right col. para. 1). Notch inhibition of liver progenitors downregulates expression of CD133 and Hes1 as evidenced by Wang (page 609, right col.; Figure 2; page 610, left col. para. 1 – 2).
Regarding the TGF-beta inhibitor is SB431542 of claim 4, Ang teaches differentiation of hESCs into liver progenitors using protocols from other research groups including using the method of Zhao where DE cells were treated with SB431542 as shown in Figure 3A and 5A (Supplemental Information page 1, last para. and page 2, para. 1).
Regarding the notch inhibitor is DAPT of claim 5, Ang teaches in Figure 4 treating liver bud progenitors with DAPT and a TGF-beta inhibitor commits the progenitors were committed to hepatocytes and not cholangiocytes (page 2199, left col. para. 1 – 3; Figure 4B). DAPT treatment of liver progenitors downregulates expression of CD133 and Hes1 as evidenced by Wang (page 609, right col.; Figure 2; page 610, left col. para. 1 – 2).
Ang does not teach CD44+ small hepatocyte progenitor cells of claim 1. However, Ang teaches the hepatocyte-like cells showed clear staining of nuclei with round morphology (Figure 5B; Figure S4H and J). Ang teaches TGF-beta and Notch inhibitors produced Albumin+ hepatocyte-like cells of high purity that secreted albumin in an amount similar to that secreted by human hepatocytes in vivo (page 2199, left col. last para. and right col. para. 1). Ang teaches the cells possessed CYP3A4 enzymatic activity and had glycogen storage function (page 2199, right col. para. 1). Ang teaches treatment with Notch inhibitor upregulated genes associated with metabolic processes (page 2199, left col. para. 2). Ang teaches culturing PSCs with Activin to induce definitive endoderm (Figure 3A and 5A). Ang teaches the roadmap outlined in Figure 7 provides a framework to understand liver commitment and may avail the as-yet-unrealized goal of generating fully functional hepatocytes (page 2203, right col. last para.). One would have been motivated to combine the teachings of Deng regarding a method of generating hepatocytes comprising generating definitive endoderm with Activin A followed by specification to hepatocytes with BMP and FGF with the teachings of Ang regarding a method of generating hepatocytes comprising generating definitive endoderm with Activin followed by specification to hepatocytes with TGF-beta and Notch inhibitors in a method to produce hepatocytes because Deng teaches hepatocytes obtained by the method can be used for the preparation of artificial livers and drug toxicity testing and drug screening and Ang teaches TGF-beta and Notch inhibitors direct cell fate to liver progenitors rather than cholangiocyte fate.
Regarding small hepatocyte progenitor cells that are CD44+ of claim 1, Sengupta teaches a method for obtaining small hepatocyte progenitor cells (SHPCs) that are CD44+ by co-culturing primary human hepatocytes (PHH) with mouse embryonic fibroblasts in a medium comprising dexamethasone and Oncostatin M and this method allows SHPCs to retain their differentiated phenotype over multiple passages (page 70, left col. and right col. para. 2; page 71, left col. para. 2 and right col. para. 2; page 77, left col. para. 2). Sengupta teaches SHPCs present a differentiated morphology reminiscent of mature hepatocytes that express CD44 (page 70, left col.). Sengupta teaches the CD44+ SHPCs can perform metabolism of acetaminophen (page 75, left col. para. 2 and right col. para. 1). Sengupta teaches SHPCs have been shown to originate from mature hepatocytes (page 70, left col.). Sengupta teaches SHPCs morphologically resemble PHHs except they were smaller than primary cells with sizes between 8 and 20 µM compared to ~30 µM for PHHs (page 71, right col. para. 2). Sengupta teaches in Figure 1C SHPCs show clear nuclei staining and the size of SHPCs (Figure 1). Sengupta teaches the SHPCs would be useful in drug discovery, toxicity testing, modeling liver diseases, and potentially be used for cellular transplantation (page 71, left col. paragraph 1; page 80, right col. para. 2- 3). Sengupta teaches while it has been possible to derive CD44+ SHPCs from livers of infants, these conditions did not allow generation of SHPCs from adult PHHs, and shortage of infant liver donor makes this work challenging to translate into practice for drug and toxicity testing (page 77, left col. last para.). Sengupta teaches PHHs are considered the gold standard for in vitro cell based metabolism studies, but are limited and lose their metabolic capacity including in xenobiotic metabolism (page 80, left col. para. 1). Sengupta teaches a major use of SHPCs will be in the field of drug development and toxicity testing because PHHs are limited and have a very short useful life in culture due to rapid de-differentiation (page 80, right col. para. 2).
Regarding “Activin A” concentration of claim 23, Deng teaches hepatocyte culture medium comprising 100 ng/ml of activin A (page 11, 0230 – 0231). Ang teaches a protocol using 100 ng/mL activin (Supplemental Information page 2, para. 3).
Regarding “bone morphogenetic protein” and “fibroblast growth factor” concentrations of claim 23, Deng teaches differentiation medium comprising 20 ng/ml of BMP4 and 30 ng/ml FGF2 (page 11, 0230 – 0231). Ang teaches 10 ng/mL FGF2 and 30 ng/mL BMP4 (Supplemental Information page 1, para. 2). Ang teaches additional protocols comprising 20 ng/mL FGF and 50 ng/mL BMP; 10 ng/mL FGF and 20 ng/mL BMP (Supplemental Information, page 2, para. 1 – 2).
Regarding “TGF-beta inhibitor” concentration of claim 23, Ang teaches 1 µM A8301 or an additional protocol using 10 µM SB431542 (Supplemental Information, page 1, para. 2 and page 2 para. 1).
Regarding “notch pathway inhibitor” concentration of claim 23, Ang teaches 10 µM DAPT or 2 µM all-trans retinoic acid (Supplemental Information page 1, para. 2).
Regarding “hepatocyte growth factor” concentration of claim 23, Deng teaches hepatocyte culture medium comprising 20 ng/ml of HGF (page 12, 0237). Ang teaches additional protocols comprising 20 ng/mL HGF and 10 ng/mL HGF or 100 ng/mL HGF (Supplemental Information page 2, para. 1 – 4).
Regarding “dexamethasone” concentration of claim 23, Deng teaches differentiation medium comprising 0.05 µM dexamethasone which is about 15 ng/ml (page 12, 0238).
[15 ng/ml dexamethasone = 0.000015 g/L x mol/392.464 g = 0.038 µm which is “about” 0.05 µM).
Ang teaches 10 µm dexamethasone and other protocols using 0.1 µM or 0.5 µM dexamethasone (Supplemental Information, page 1, para. 2 and page 2, para. 1 and 3). Sengupta teaches media comprising 1 µM dexamethasone (page 71, left col. para. 2).
Regarding “Oncostatin M” concentration of claim 23, Deng teaches hepatocyte culture medium comprising 100 ng/ml OSM (page 12, 0239). Ang teaches 10 ng/mL OSM (Supplemental Information, page 1, para. 2). Ang teaches additional protocols using 10 ng/mL or 20 ng/mL or OSM (Supplemental Information page 2, para. 1 – 3). Sengupta teaches media comprising 10 µg/ml Oncostatin M (page 71, left col. para. 2), which is about 0.45 µM. [10 µg/ml = 0.01 g/L x mol/22000 g = 0.45 µM]
It would have been obvious prior to the effective filing date of the invention as claimed for the person of ordinary skill in the art to combine the teachings of Deng regarding a method of generating hepatocytes from hESCs or iPS cells with the teachings of Ang regarding a method of generating hepatocytes comprising generating definitive endoderm with Activin followed by specification to hepatocytes with TGF-beta and Notch inhibitors with the teachings of Sengupta regarding a method of producing SHPCs that are CD44+ by culturing hepatocytes with mouse embryonic fibroblasts in a medium containing dexamethasone and Oncostatin M to arrive at the claimed method where hESCs or iPS cells in the presence of MEFs are cultured with Activin A followed by culturing in media comprises a BMP, FGF, TGF-beta inhibitor, and notch pathway inhibitor followed by culturing in media comprising dexamethasone and Oncostatin M to obtain small hepatocyte progenitor cells that are CD44+ wherein the CD44+ small hepatocyte progenitor cells are not derived from primary human hepatocytes. One would be motivated to combine the teachings of Deng, Ang, and Sengupta to produce SHPCs from human pluripotent stem cell-derived hepatocytes rather than primary human hepatocytes for drug testing as Deng teaches hepatocytes obtained by the method can be used for drug toxicity testing and drug screening and Sengupta teaches a major use of SHPCs will be in the field of drug development and toxicity testing because PHHs are limited and have a very short useful life in culture due to rapid de-differentiation. One would have a reasonable expectation of success in combining the teachings as Deng teaches the differentiated cells had drug-induced P450 enzyme activity similar to that of hepatocytes indicating that the method induced differentiation of hESC and iPS cells to hepatocytes, Ang teaches the cells possessed CYP3A4 enzymatic activity, and Sengupta teaches the CD44+ SHPCs can perform metabolism of acetaminophen.
Double Patenting
The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A nonstatutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg, 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969).
A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP § 2146 et seq. for applications not subject to examination under the first inventor to file provisions of the AIA . A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b).
The filing of a terminal disclaimer by itself is not a complete reply to a nonstatutory double patenting (NSDP) rejection. A complete reply requires that the terminal disclaimer be accompanied by a reply requesting reconsideration of the prior Office action. Even where the NSDP rejection is provisional the reply must be complete. See MPEP § 804, subsection I.B.1. For a reply to a non-final Office action, see 37 CFR 1.111(a). For a reply to final Office action, see 37 CFR 1.113(c). A request for reconsideration while not provided for in 37 CFR 1.113(c) may be filed after final for consideration. See MPEP §§ 706.07(e) and 714.13.
The USPTO Internet website contains terminal disclaimer forms which may be used. Please visit www.uspto.gov/patent/patents-forms. The actual filing date of the application in which the form is filed determines what form (e.g., PTO/SB/25, PTO/SB/26, PTO/AIA /25, or PTO/AIA /26) should be used. A web-based eTerminal Disclaimer may be filled out completely online using web-screens. An eTerminal Disclaimer that meets all requirements is auto-processed and approved immediately upon submission. For more information about eTerminal Disclaimers, refer to www.uspto.gov/patents/apply/applying-online/eterminal-disclaimer.
10. Claims 1 – 5, 7 – 8, and 23 remain rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1 – 7 of U.S. Patent No. 11566229. Although the claims at issue are not identical, they are not patentably distinct from each other because instant claim 1 is anticipated by patent claim 1, 4, and 5.
The instant claims and patent claims are drawn to methods for obtaining small hepatocyte progenitor cells wherein the small hepatocyte progenitor cells are CD44+. Instant claim 1 recites culturing human embryonic stem cells or induced pluripotent stem cells in the presence of embryonic fibroblasts to obtain CD44+ small hepatocyte progenitor cells. Patent claim 1 recites culturing human hepatocytes in the presence of embryonic fibroblasts, patent claim 4 recites the human hepatocytes are selected from the group consisting of primary human hepatocytes and pluripotent stem cell-derived human hepatocytes, and patent claim 5 recites the pluripotent stem cell-derived hepatocytes are selected from the group consisting of embryonic stem cell-derived hepatocytes or induced pluripotent stem cell-derived hepatocytes. Patent claim 2 recites the culture medium further comprises dexamethasone and patent claim 3 recites the culture medium further comprises Oncostatin M. Instant claim 1 recites the culture media comprises dexamethasone and Oncostatin M. Patent claim 6 recites the embryonic fibroblasts are mouse embryonic fibroblasts or human embryonic fibroblasts. Instant claim 7 recites the embryonic fibroblasts are mouse embryonic fibroblasts or human embryonic fibroblasts. Patent claim 7 recites the human hepatocytes are cultured for about 6 days to obtain a cell population comprising CD44+ small hepatocyte progenitor cells. Instant claim 8 recites the cells are cultured for about 18 days. Therefore, patent claims 1, 4, and 5 are in essence a “species” of the generic invention of instant claim 1. It has been held that a generic invention is “anticipated” by a “species” within the scope of the generic invention.
Applicant’s Arguments/ Response to Arguments
11. Applicant argues: On page 7 para. 2 – 4 – page 8, para. 1, Applicant traverses the grounds of rejection over the cited prior art because Deng and Ang are uniformly focused on generating hepatocyte-like cells, not small hepatocyte progenitor cells characterized by CD44 expression.
Response to Arguments: This is not found persuasive because Ang teaches the prevailing view to generate hepatocyte-like cells from hPSCs is roughly divided into three stages where current protocols start with (1) Activin/TGF-beta to induce endoderm; followed by (2) BMP and FGF to specify liver progenitors; and finally (3) hepatocyte growth factor, Oncostatin M, and dexamethasone (page 2193, left col. para. 3). As such, Deng teaches a method of generating hepatic progenitors from hESCs or iPS cells comprising culturing hESCs or iPS cells on mouse embryonic fibroblast (MEF) feeder layer in a culture media comprising Activin A to produce definitive endoderm (DE) (page 12, 0245; page 11, 0228 – 0231). Deng teaches initiation of hepatocyte differentiation by culturing DE in a media comprising a bone morphogenetic protein and a fibroblast growth factor (page 12, 0246; page 11, 0232 – 0234). Deng teaches proliferation of differentiated cells in media comprising HGF (page 12, 0237 and 0247; page 11, 0235 – 0236). Deng teaches maturing hepatic progenitors by culturing in media comprising Oncostatin M and dexamethasone (page 12, 0238 – 0240 and 0248). Deng does not teach a TGF-beta inhibitor or a notch pathway inhibitor of claim 1. However, Ang teaches differentiation of hESCs into liver progenitors using protocols from other research groups including using the method of Zhao where DE cells were treated with SB431542 as shown in Figure 3A and 5A (Supplemental Information page 1, last para. and page 2, para. 1). Ang teaches in Figure 4 treating liver bud progenitors with DAPT and a TGF-beta inhibitor commits the progenitors were committed to hepatocytes and not cholangiocytes (page 2199, left col. para. 1 – 3; Figure 4B). One would have been motivated to combine the teachings of Deng and Ang because Deng teaches hepatocytes obtained by the method can be used for the preparation of artificial livers and drug toxicity testing and drug screening and Ang teaches TGF-beta and Notch inhibitors direct cell fate to liver progenitors rather than cholangiocyte fate. Therefore, the combination of Deng and Ang teach the limitations of the method steps of claim 1 and do not teach the “primary human hepatocytes” of amended claim 1. The claimed method does not recite any additional method steps to obtain SHPCs other than those taught by Deng in view of Ang.
Sengupta teaches a method for obtaining small hepatocyte progenitor cells (SHPCs) that are CD44+ by co-culturing primary human hepatocytes (PHH) with mouse embryonic fibroblasts in a medium comprising dexamethasone and Oncostatin M and this method allows SHPCs to retain their differentiated phenotype over multiple passages (page 70, left col. and right col. para. 2; page 71, left col. para. 2 and right col. para. 2; page 77, left col. para. 2). Sengupta teaches SHPCs morphologically resemble PHHs except they were smaller than primary cells with sizes between 8 and 20 µM compared to ~30 µM for PHHs (page 71, right col. para. 2). Sengupta teaches while it has been possible to derive CD44+ SHPCs from livers of infants, these conditions did not allow generation of SHPCs from adult PHHs, and shortage of infant liver donor makes this work challenging to translate into practice for drug and toxicity testing (page 77, left col. last para.). Sengupta teaches PHHs are considered the gold standard for in vitro cell based metabolism studies (page 80, left col. para. 1). Sengupta teaches a major use of SHPCs will be in the field of drug development and toxicity testing because PHHs are limited and have a very short useful life in culture due to rapid de-differentiation (page 80, right col. para. 2). Therefore, one would be motivated to use the hepatocytes obtained from pluripotent stem cells by the method of Deng in view of Ang in lieu of the PHHs in the method of Sengupta because Sengupta teaches a major use of SHPCs will be in the field of drug development and toxicity testing because PHHs are limited and have a very short useful life in culture due to rapid de-differentiation. One would have a reasonable expectation of success in combining the teachings as Deng and Ang teach the cells produced from pluripotent stem cells show activity of hepatocytes and Sengupta teaches SHPCs are obtained by culturing hepatocytes with dexamethasone and Oncostatin M, which is the same media of Deng for maturing hepatic progenitors.
Applicant argues: On page 8 para. 4 – 5 and page 9, Applicant asserts that Sengupta operates in a fundamentally different biological context that Deng and Ang because Sengupta teaches co-culturing primary human hepatocytes with MEFs in media containing dexamethasone and Oncostatin M. Applicant asserts that nothing in Sengupta suggests that its approach could be applied to or would be successful with PSC-derived hepatocytes, much less that it would yield SHPCs as Sengupta highlights the challenges and limitations associated with hepatocyte sources underscoring that its SHPCs arise from hepatocyte populations already possessing mature hepatic identity. Applicant asserts that a person of ordinary skill in the art would not have had a reasonable expectation of success in combining the cited references.
Response to Arguments: This is not found persuasive because Deng teaches the use of the hepatocytes obtained by the method for the preparation of artificial livers or testing of drug toxicity or drug screening (page 2, 0023; page 4, 0055; page 5, 0074 – 0075). Deng teaches the liver plays an important role in metabolism in the human body and possesses many critical functions including glycogen synthesis and detoxification (page 1, 0005). Deng teaches the differentiated cells express AFP, Alb, CD18, AAT, and CYP3A4 (page 13, 0268). Deng teaches the differentiated cells had glycogen synthesis and storage function, urea synthesis function, albumin secretion function, and drug-induced P450 enzyme activity similar to that of hepatocytes indicating that the method induced differentiation of hESC and iPS cells to hepatocytes (page 13, 0270, 0272, 0274, 0277). Ang teaches TGF-beta and Notch inhibitors produced Albumin+ hepatocyte-like cells of high purity that secreted albumin in an amount similar to that secreted by human hepatocytes in vivo (page 2199, left col. last para. and right col. para. 1). Ang teaches the cells possessed CYP3A4 enzymatic activity and had glycogen storage function (page 2199, right col. para. 1). Thus, Deng and Ang teach functional hepatocytes can be produced from hESCs or hiPSCs and Sengupta teaches a method of producing SHPCs from hepatocytes by culturing in media containing Oncostatin M and dexamethasone which is the same media of Deng for maturing hepatic progenitors. Therefore, one of ordinary skill in the art would have a reasonable expectation of success in culturing the hepatocytes of Deng and Ang in media containing dexamethasone and Oncostatin M with MEFs to produce SHPCs.
Applicant argues: On page 10, para. 1, Applicant asserts that it was not known whether hepatocyte-like cells derived from PSCs could recapitulate the biological state of mature PHHs or be reprogrammed or expanded into SHPCs and the cited references are silent as to whether Sengupta’s SHPC derivation method would function when applied to PSC-derived hepatocytes and nothing in Ang of Deng suggests inducing or enriching for SHPCs.
Response to Arguments: This is not found persuasive because Deng teaches the use of the hepatocytes obtained by the method for the preparation of artificial livers or testing of drug toxicity or drug screening (page 2, 0023; page 4, 0055; page 5, 0074 – 0075). Deng teaches the differentiated cells had glycogen synthesis and storage function, urea synthesis function, albumin secretion function, and drug-induced P450 enzyme activity similar to that of hepatocytes indicating that the method induced differentiation of hESC and iPS cells to hepatocytes (page 13, 0270, 0272, 0274, 0277). Ang teaches the cells possessed CYP3A4 enzymatic activity and had glycogen storage function (page 2199, right col. para. 1). Thus, Ang and Deng teach that the hepatocytes produced from PSCs function as mature hepatocytes and could even be used to prepare artificial livers. Therefore, one of ordinary skill in the art would have a reasonable expectation of success in obtaining SHPCs from the method taught by Deng in view of Ang and Sengupta.
Applicant argues: On page 10 paragraph 2, Applicant asserts that the Office Action’s reasoning improperly reconstructs Applicant’s claimed invention by selectively extracting elements from unrelated references with the benefit of hindsight.
Response to Arguments: In response to applicant’s argument that the examiner’s conclusion of obviousness is based upon improper hindsight reasoning, it must be recognized that any judgment on obviousness is in a sense necessarily a reconstruction based upon hindsight reasoning. But so long as it takes into account only knowledge which was within the level of ordinary skill at the time the claimed invention was made, and does not include knowledge gleaned only from the applicant’s disclosure, such a reconstruction is proper. See In re McLaughlin, 443 F.2d 1392, 170 USPQ 209 (CCPA 1971).
Applicant argues: On page 10 paragraph 3, Applicant asserts that the claimed methods do not require PHHs and thus the claimed methods have real-world advantages over methods known in the prior art.
Response to Arguments: As stated on page 10 of the maintained rejection, one would be motivated to combine the teachings of Deng, Ang, and Sengupta to produce SHPCs from human pluripotent stem cell-derived hepatocytes rather than primary human hepatocytes for drug testing as Deng teaches hepatocytes obtained by the method can be used for drug toxicity testing and drug screening and Sengupta teaches a major use of SHPCs will be in the field of drug development and toxicity testing because PHHs are limited and have a very short useful life in culture due to rapid de-differentiation.
Applicant argues: On page 10 last para., Applicant asserts that the amendments to the claims obviate these rejections as none of the claims of the cited patent render the pending claims obvious.
Response to Arguments: The rejection is maintained as patent claim 1 broadly recites “culturing human hepatocytes” and patent claim 4 recites “wherein the human hepatocytes are selected from the group consisting of primary human hepatocytes and pluripotent stem cell-derived human hepatocytes” and patent claim 5 recites “wherein the pluripotent stem cell-derived hepatocytes are selected from the group consisting of embryonic stem cell-derived hepatocytes or induced pluripotent stem cell-derived hepatocytes”.
Conclusion
No claims allowed
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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ZANNA M BEHARRY whose telephone number is (571)270-0411. The examiner can normally be reached Monday - Friday 8:45 am - 5:45 pm.
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/Z.M.B./Examiner, Art Unit 1632
/MARCIA S NOBLE/Primary Examiner, Art Unit 1632
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