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 .
Status of Claims
Claims 2-3, 7-9, and 17-18, are cancelled. Claims 1, 4-6, and 10-16 are pending and under exam.
MAINTAINED 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.
Claims 1, 4-5, and 10-13 are rejected under 35 U.S.C. 103 as being unpatentable over Benedetti et al ( EMBO Mol Med. 2018 Feb; hereinafter "Benedetti;" See PTO-892) in view of Ban et al (Proc Natl Acad Sci U S A. 2011 Aug 23; hereinafter "Ban;" See IDS of 5/4/2023).
Regarding claims 1, 4-5, and 10-12: Benedetti showed “reversible cell immortalisation mediated by lentivirally delivered excisable hTERT and Bmi1 transgenes extended cell proliferation, enabling transfer of a novel DYS‐HAC into DMD satellite cell‐derived myoblasts and perivascular cell‐derived mesoangioblasts.” (See Benedetti Abstract). Benedetti noted that “Genetically corrected cells maintained a stable karyotype, did not undergo tumorigenic transformation and retained their migration ability,” and that remained myogenic in vitro. (See Benedetti Abstract). It is noted that Benedetti also used varying “concentrations of IDLV NLS‐Cre for 24 h [multiplicity of infection (MOI) 0.5, 1, 2.5, 5 and 10]. Cells were kept in culture for 2 weeks to allow dilution of excised transgenes, which might be otherwise detected by DNA analyses. Quantitative real‐time PCR analysis of hTERT and Bmi1 transgenes was performed on Cre‐transduced, immortalized mesoangioblasts. Dose‐dependent reduction in both hTERT and Bmi1 was observed in all samples transduced with IDLV NLS‐Cre, ranging from 75% (MOI 0.5) up to 99%. These data demonstrate that IDLV NLS‐Cre recombinase efficiently excises loxP‐flanked hTERT and Bmi1 transgenes in human mesoangioblasts.” (See Benedetti, p. 262, col. 1, last para). As such Benedetti taught reversible engineering of somatic stem cells (as required by claims 4-5) using hTERT and Bmi1 transgenes (as required by claims 2-3), which induce immortalization. It is noted that Benedetti did not teach using a Sendai virus vector loaded with an immortalizing gene for introducing the immortalization genes.
Ban taught that a “Sendai virus vector, an RNA virus vector that carries no risk of integrating into the host genome, is a practical solution for the efficient generation of safer iPSCs.” (See Ban Abstract). Ban “improved the Sendai virus vectors by introducing temperature-sensitive mutations so that the vectors could be easily removed at nonpermissive temperatures.” (See Ban Abstract; as required by claim 10). Ban taught that methods such as Cre/lox system “suffer from low efficiency, require repetitive induction, and/or produce insufficient excision of integrated vectors.” (See Ban p. 14234. Col. 1, first para) Ban taught “use of Sendai virus (SeV) vectors. SeV, a member of the Paramyxovirdae family, [[is]] an enveloped virus with a single-stranded, negative-sense, nonsegmented RNA genome of ∼15 kb” (See Ban p. 14234. Col. 1, first para; as required by claims 7-9) as an alternative technology.
It would have been obvious for a person of ordinary skill in the art before the effective filing date of the present invention to substitute the non-integrating Sendai virus vector of Ban for the Cre/lox based integrating system of Benedetti for the integration of immortalization genes such as hTERT and Bmi for achieving the same purpose. Because both references teach delivery of genes into mammalian or stem cells, the desired outcome is predictable from the known properties of the SeV vectors, and as such a person of ordinary skill in the art will have a reasonable expectation of success in combining the teachings or substituting one gene delivery method for another.
It is further noted that Ban taught use of SeV temperature sensitive mutants for expression or removal of SeV vectors. For example, Ban disclosed a TS15 vector which “exhibited greater temperature sensitivity;” where “GFP expression was barely detected at 37 °C;” (See Ban p. 14235, 1st para), while robust GFP expression was detected at 35 °C. (See Ban Fig. 1B). A person of ordinary skill in the art in reading Ban and Benedetti would have easily understood the need for transient expression of immortalization genes and the need to remove SeV by changing the culture temperature from 35°C to 37°C. (as required by claims 11-12) It is further noted that Ban tested expression of GFP from 32-39°C and found that irreversible inactivation of gene expression only occurred at 37C. One of ordinary skill in the art would have readily optimized the claimed temperature using known methods in the art. “[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.” See MPEP 2144.05 II.A.
Regarding claim 13: Benedetti taught a method of generating immortalized cell lines of mammalian stem cells by introducing hTERT and Bmi in a Cre/lox system. Ban taught a method to achieve the same product by introducing a SeV vector. As indicated above, it would have been obvious to a person of ordinary skill in the art to arrive at the same product using the method taught by Ban for the reasons indicated above. It is submitted that it would have further been obvious to a person of ordinary skill in the art to obtain a genetically and phenotypically homogenous cell culture by cloning the immortalized cell line as claimed. It is noted that Benedetti conducts cloning of immortalization genes and further cultures the cells to further produce genetically identical copies which reads on the claimed step of cloning. (See For example, Benedetti Figures 5C-E).
Claims 1, 6, and 14-16 are rejected under 35 U.S.C. 103 as being unpatentable over Gong et al ( J Biomed Sci; Published 2011; hereinafter "Gong;" See PTO-892) in view of Ban et al (Proc Natl Acad Sci U S A. 2011 Aug 23; hereinafter "Ban;" See IDS of 5/4/2023).
Regarding claims 1, 6 and 14-15: Gong taught that “MSCs are easily subject to aging and senescence because of their finite ability of self-renewal. MSCs senescence seriously affected their application prospects as a promising tool for cell-based regenerative medicine and tissue engineering.” (See Gong Abstract). Gong “established a reversible immortalized mesenchymal stem cells (IMSCs) line (as required by claim 15) by using SSR#69 retrovirus expressing simian virus 40 large T (SV40T) antigen as an alternative to primary MSCs.” (See Gong Abstract). Gong used a “retroviral vector SSR#69 that expresses SV40T antigen and hygromycin resistant gene flanked with loxP sites.” (See Gong p. 2, col. 2, para 4). Gong indicated that “[t]he reversal of IMSCs was achieved by adenovirus containing Cre (Ad-Cre) mediated site-specific Cre/loxP recombination.” (See Gong p. 3, para 1). As such Gong taught the feasibility and the need to produce reversibly immortalized mesenchymal stem cells. It is noted that Gong did not teach the use of using a Sendai virus vector loaded with an immortalizing gene for introducing the immortalization genes.
However, as indicated above, Ban taught the use of SeV vectors for reversibly introducing genes of interests.
It would have been obvious for a person of ordinary skill in the art before the effective filing date of the present invention to substitute the non-integrating Sendai virus vector of Ban for the Cre/lox based integrating system of Gong for the integration of immortalization genes such as hTERT and Bmi for achieving the same purpose. Because Both references teach delivery of genes into mammalian or MSC cells, the desired outcome is predictable from the known properties of the SeV vectors, and as such a person of ordinary skill in the art will have a reasonable expectation of success in combining the teachings or substituting one gene delivery method for another.
Regarding claim 16: Gong taught that “[m]esenchymal stem cells (MSCs) can be induced to differentiate into neuronal cells under appropriate cellular conditions and transplanted in brain injury and neurodegenerative diseases animal models for neuroregeneration studies.” (See Gong Abstract). Gong further taught that immortalized MSCs can be used for transplantation in nude mice. (See Gong Abstract.) As such Gong taught a regenerative medicine product comprising the immortalized cell of claim 14, as claimed.
Response to Applicant Arguments: Applicants argued that the cited immortalization references (Benedetti and Gong) rely on chromosomally integrating viral vectors, which are unsuitable for regenerative medicine due to safety concerns such as risk of cancer. Applicants further pointed out that Ban only taught use of Sendai virus for transient gene expression in iPS cells and not for long term expression in somatic cells for the purpose of immortalization. According to the Applicant a person of ordinary skill would not have expected a non-integrating, cytoplasmic virus to support sustained expression of immortalizing genes due to dilution during cell division, which allegedly teaches away from their use. Applicant asserted that culturing the virus at 33ºC-35ºC is unobvious as the prior art only taught Sendai virus studies at 37ºC and the prior art did not suggest lowering temperature to achieve long term expression. Applicant submitted that the invention unexpectedly enables long-term proliferation of somatic cells, while maintaining their phenotype.
Applicant’s arguments have been considered but are not found to be persuasive. It is initially noted that obviousness cannot be argued by attacking the references individually. Benedetti and Gong were cited for their teaching that the expression of immortalizing gene Bmi-1 and/or TERT gene induces long-term proliferation of somatic cells. Although these references employ chromosomally integrating viral vectors, they nonetheless establish the use of these genes for immortalization. The fact that Benedetti or Gong used lentivirus does not limit the use of their teachings to those vectors or preclude alternative gene delivery systems. As pointed out in the non-final rejection of 10/21/2025, Ban explicitly taught the use of Sendai virus as an alternative for introducing cells, which was motivated by avoidance of genome integration while introducing known immortalizing genes.
Applicant’s assertion that Sendai virus vectors are limited to transient expression is not persuasive. Ban disclosed that Sendai virus persistence and gene expression are temperature-dependent and demonstrated that culturing infected cells at 32ºC and 35ºC maintained expression, with loss of virus at higher temperatures. As such Ban does not teach away from sustained expression. It is asserted that 32 and 35 C falls squarely within the claimed temperature range. Additionally, selecting an appropriate temperature would have been routine for a person of ordinary skill in the art and does not impart patentable distinction. Applicant’s arguments regarding the differences in the ultimate purpose (iPS versus somatic cells) are not persuasive because the claims are not restricted to any specific type of cells. Further, the cited prior art does not teach away from using the same technology for somatic cells.
As such the rejection under 35 U.S.C. 103 is maintained.
Conclusion
No claim is free of art or allowable.
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 JAGAMYA VIJAYARAGHAVAN whose telephone number is (703)756-5934. The examiner can normally be reached 9:00a-5:00p.
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/JAGAMYA NMN VIJAYARAGHAVAN/Examiner, Art Unit 1633
/EVELYN Y PYLA/Primary Examiner, Art Unit 1633