NOTE: The examiner of your application in the USPTO has changed. To aid in correlating any papers for this application, all further correspondence regarding this application should be directed to Examiner Aditi Dutt.
Notice of Pre-AIA or AIA Status
1. The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
DETAILED ACTION
Status of Application, Amendments and/or Claims
2. Applicant’s response dated 11/6/2025 is considered and entered into record. Claims 1-2, 4-11 and 13-22 of the amendment dated 11/26/2024, are currently pending.
3. Claims 13-21 are withdrawn from further consideration pursuant to 37 CFR 1.142(b), as being drawn to a nonelected inventions, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on 22 November 2023.
4. Claims 1-2, 4-11 and 22, drawn to a method of producing neurite outgrowth in a neuron, are being considered for examination in the instant application.
Rejections maintained
Claim Rejection - 35 USC § 103
5. 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.
6. 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.
7. Claims 1-2 and 4-11, are rejected under AIA 35 U.S.C. 103 as being unpatentable over Pereira et al. (Invest Ophthal Vis Sci, 2010, 51:3) as evidenced by Tang et al. (Regen Biomat, 2014, 91-102), in view of Nosrat et al. (Dev Biol, 2001, 238) in further view of Nagashima et al. (Sci Rep, 2017, 7:13500). The rejection is maintained for reasons of record in the Office Action dated 6/6/2025.
8. The claims are directed to a method of producing neurite outgrowth in a neuron comprising culturing neural crest-derived stem cells (NC) without a scaffold with fibroblast growth factor 2 (FGF2), to produce a scaffold free tissue structure (tissue sheet), wherein the NCs produce one or more neurotrophic factors (NTF); and exposing neural tissue comprising neuron to the NTFs for a time sufficient to produce neurite outgrowth from a neuron, thereby producing neurite extension (claims 1, 2) by implanting the tissue structure adjacent to neural tissue in a patient (claim 4), the damaged nerve tissue is contacted with the tissue structure at a site of nerve damage (claim 5); wherein: the damaged nerve tissue is a peripheral nerve (claim 6); the nerve tissue is damaged from conditions listed in claim 7; the neural tissue is exposed to the NTFs by culturing the tissue structure adjacent to the neural tissue, or by culturing the neural tissue in media conditioned by the tissue structure (claim 8); the NCs are from the same organism as the neural tissue (claim 9); the NCs are dental pulp cells (DPC) (claim 10); and the FGF2 concentration in the culture medium is 0.25 ng/ml to 25 ng/ml (claim 11).
9. Regarding claims 1, 2 and 10, Pereira teaches a tissue-engineered cell sheet (tissue structure) composed of human undifferentiated immature dental pulp stem cells (hereafter DPSCs) (i.e., neural crest-derived stem cells) used for ocular surface reconstruction (see abstract). Pereira seeded the DPSCs directly without any feeder cell layer in temperature-responsive cell culture dishes, which comprise poly(N-isopropylacrylamide) (pg. 1408, right col., par. 5), a polymer which facilitates cell adhesion and growth in normal culture conditions and is used in scaffold-free tissue engineering methodologies to fabricate tissue-like grafts, as evidenced by Tang (Introduction, right col., par. 2). Pereira cultured the cells until they reached confluence
and formed a cell sheet (pg. 1409, left col., par. 4).
10. The DPSC sheet was transplanted directly onto rabbit burned corneal beds displaying induced total limbal stem cell deficiency (see abstract; pg. 1409, right col., par. 1) and the transplantation of tissue-engineered DPSC sheets was successful for the reconstruction of corneal epithelium (pg. 1413, left col., par. 5). Pereira discloses that it has been suggested that benefits observed from transplantation of DPSCs is due to secretion of paracrine factors by these cells (pg. 1412, left col., par. 2).
11. Pereira does not teach culturing the DPSCs in the presence of FGF2. Pereira fails to teach the limitations wherein the NCs of the cell sheet produce one or more NTFs and exposing neural tissue comprising a neuron to the one or more NTFs produced by the cells of the cell sheet for a time sufficient to produce neurite outgrowth from a neuron, as recited in claim 1.
12. However, Nosrat discloses a method of culturing dental pulp cells (neural crest derived stem cells) and coculturing the dental pulp cells with trigeminal neurons (see abstract). Regarding claims 1 and 8, Nosrat discloses that dental pulp cells produce neurotrophic factors in vitro and further discloses observing neurite extension of the trigeminal neurons and enhanced survival, thus, by coculturing dental pulp cells with trigeminal neurons, Nosrat discloses exposing the neural tissue to the neurotrophic factors produced by the dental pulp cells for a time sufficient to produce neurite outgrowth (trigeminal neurons thrived well and sent out neurites starting after 1 day in the coculture (see whole document; pg. 123, Results par. 1-2; Figs. 2 and 3).
13. Furthermore, regarding claims 1, 4 and 5, Nosrat performed intraocular transplantations and spinal cord transplantations in rats by obtaining dental pulp tissue and performing intraocular grafting of the pulpal tissue or inserting the tissue into spinal cord lesions, respectively (pg. 121, right col., par. 4 to pg. 122, left col., par. 1; pg. 122, right col., par. 3). Regarding claim 7, Nosrat performed a hemisection of the spinal cord to produce loss of motoneuron population (pg. 127, right col., par. 2). Nosrat observed innervation of the dental pulp grafts in the case of intraocular transplantation (pg. 126, right col., par. 2 to pg. 127, left col., par. 1), and also observed, in the case of spinal cord transplantation, an increased number of surviving motoneurons associated with strong expression of GDNF (neurotrophic factor), which has been proposed to be a potent survival factor for motoneurons (pg. 127, right col., par. 2). Regarding claim 9, Nosrat discloses that the risk of graft rejection would be minimized if autologous grafts could be used, since the dental pulp is easily accessible (pg. 129, right col.,
par. 3).
14. Regarding claim 6, Nosrat discloses grafting dental pulp tissue into hemisected spinal cord and motoneurons, which are part of the central nervous system. However, Nosrat also discloses a coculture of dental pulp cells and trigeminal neurons, which resulted in innervating trigeminal nerve fibers (see abstract). Therefore, while Nosrat does not disclose contacting the dental pulp cells or a tissue structure made of dental pulp cells at a site of nerve damage wherein the damaged nerve tissue is a peripheral nerve, it would have been obvious to do so since Nosrat showed that dental pulp cells are capable of promoting survival and neurite outgrowth in vitro in neurons from the peripheral nervous system.
15. Neither Pereira nor Nosrat disclose culturing neural crest-derived stem cells in the presence of FGF2.
16. Nagashima discloses treating dental pulp cells with FGF2 before transplanting the cells into the injury site immediately after complete transection of the rat spinal cord (see abstract). Nagashima found that pre-treating dental pulp cells with FGF2 significantly increased locomotor function recovery in spinal cord injury (SCI) rats in response to dental pulp cell transplantation (pg. 8, par. 2). Nagashima also found that the FGF2 priming protected the cells from H₂O₂-inducing cell death in vitro and promoted axonal regeneration because of the increased number of dental pulp cells surviving in the spinal cord after transplantation (pg. 8, par. 2). Nagashima concluded that surviving dental pulp cells could increase the availability of neurotrophic factors in the lesion site (abstract). Regarding claim 11, the dental pulp cells were
treated with FGF2 in a concentration of 10 ng/mL (pg. 9, par. 5-7).
17. Accordingly, it would have been obvious to one of ordinary skill in the art at the effective filing date of the claimed invention to combine the teachings of Pereira regarding a scaffold-free DPSC sheet with the teachings of Nosrat regarding the effects of exposing neural tissue to neurotrophic factors produced by DPSCs and the teachings of Nagashima regarding the treatment of DPSCs with FGF2 before transplantation, to arrive at the invention as claimed. A person of ordinary skill in the art would have been motivated to modify the method of Pereira by culturing the DPSCs in the presence of FGF2 before transplantation of the cell sheet with the purpose of enhancing the cell sheet survival and neuronal regeneration as a result of increased availability of neurotrophic factors in the lesion site, as taught by Nagashima, by substituting the
use of the scaffold-free DPSC sheet to promote corneal regeneration as taught by Pereira for regenerating neural tissue instead, in view of the teachings of Nosrat that exposing neural tissue, such as by spinal cord transplantation, to the neurotrophic factors produced by dental pulp cells for a sufficient time produces neurite outgrowth.
18. One of ordinary skill in the art would have had a reasonable expectation of success in making the combination to arrive at the claimed method since scaffold-free DPSC sheets had already been successfully generated, addition of FGF2 to the culture of DPSCs is taught in the art as an approach to improve not only the survival of the tissue graft, but also the recovery and regeneration of the damaged tissue and the production and effects of neurotrophic factors by DPSCs cultured in confluence with neural tissue had been described in the prior art in a transplantation landscape.
19. Therefore, the invention as a whole was prima facie obvious to one of ordinary skill in the art at the time the invention was made, especially in the absence of evidence to the contrary.
20. Claim 22 is rejected under 35 U.S.C. 103 as being unpatentable over Pereira et al. (2010) as evidenced by Tang et al. (2014), in view of Nosrat et al. (2001) and Nagashima et al. (2017) as applied to claims 1, 2 and 4-11 above, in further view of Wei et al. (J Cell Physiol 227:3216-3224, 2012). The rejection is maintained for reasons of record in the Office Action dated 6/6/2025.
21. Claim 22 recites that the NCs are cultured in the presence of ascorbic acid.
22. The teachings of Pereira, Tang, Nosrat and Nagashima can be found in the previous rejection above.
23. Regarding claim 22, none of the cited references teach culturing the neural crest-derived stem cells in the presence of ascorbic acid.
24. Wei teaches adding vitamin C (ascorbic acid) to induce periodontal ligament stem cells (PDLSCs) (neural crest-derived stem cells) to form high quality cell sheets (Results in pg. 3218). The obtained PDLSCs sheet preserved the intercellular junctions and endogenous ECM, and retained their cellular phenotypes (pg. 3219, right col., par. 1). In addition, vitamin c served as a positive modulator of PDLSC proliferation and enhanced the production of collagen and other ECM constituents during vitamin C-induced cell sheet construction (pg. 3219, right col., par. 2; pg. 3223, left col., par. 2). Vitamin C was added to PDLSC culture to form cell sheets, and a cell sheet obtained from a temperature-responsive culture dish was used as a control (pg. 3217, right col., par. 1). The vitamin C-induced cell sheet was of similar quality to the cell sheet
derived from the temperature-responsive culture dish but the success rate for harvesting the cell sheet obtained with added vitamin C was 100% and was only 80% using the temperature-responsive culture dish (pg. 3219, left col., par. 1). Similarly, the mRNA levels of ECM elements were higher for cell sheets obtained with added vitamin C compared to the cell sheets obtained using the temperature-responsive culture dish (pg. 3219, right col., par. 4).
25. Accordingly, it would have been obvious to a person of ordinary skill in the art at the effective filing date of the claimed invention to culture the neural crest-derived stem cells in the presence of ascorbic acid (vitamin C) since its effects on neural crest-derived stem cell sheet formation were described in the prior art, as taught by Wei. One of ordinary skill would have been motivated to modify the method of obtaining a DPSC sheet as taught by Pereira in combination with the teachings of Nosrat and Nagashima, as discussed in the rejection above, by culturing the cells in the presence of ascorbic acid as taught by Wei, with the purpose of producing an improved high-quality neural crest-derived stem cell sheet, having a better harvesting success rate and higher ECM elements that allow for a robust sheet formation.
26. Therefore, the invention was prima facie obvious to one of ordinary skill in the art at the time the invention was made, especially in the absence of evidence to the contrary.
Declaration under 37 C.F.R. § 1.132
27. The declaration of Dr. Fatima Syed under 37 CFR § 1.132, dated 10/21/2025 (referred to as Syed declaration) is acknowledged and fully considered.
28. Paragraph 3 of the declaration expresses disagreement with the Examiner’s analysis that Pereira and Nosrat “evidence a predictability in the art” at the time of filing of the present invention.
29. Addressing Pereira teachings about the temperature-responsive substrate for cell culture, and Tang evincing that the isopropylacrylamide (IPA) (temperature responsive culture dish) used in the Pereira reference is a “scaffold-free system” in paragraph 4 of the declaration, Dr. Syed declares that the teachings do not render “predictable the level of cellularity seen with the claimed method”, because at the time of filing, the “effect that FGF2 has on cellularity and the formation of cell sheets” was not considered.
30. Paragraph 5 of the declaration addresses the discrepancies in Nosrat art, and states that Nosrat does not disclose “a scaffold-free system”, “effect of different degrees of cell confluence on NTF expression”, “degree of confluency of these cells when RNA was isolated”, and “the cells were not cultured as cell sheets”, therefore, the effect of cell sheet culture on NTF expression cannot be determined or predicted. The paragraph adds that the relevancy of the reference teachings is significantly reduced, because while it teaches that DPSCs induced “neurite outgrowth in neuronal cells in vitro”, it also states that the cells of the co-culture experiment “had not reached confluency”.
31. In paragraph 6, while taking note that the Lui reference is not currently cited, the declaration refers to Figure 8 of the reference to show unpredictability that any stem cell can be suitable for cell sheet formation, since the figure discloses formation of a “better cell sheet” showing more ECM and fibrils with tendon-derived stem cells (TDSC) as compared to bone marrow derived stem cells (BMSC).
32. Paragraph 7 of the declaration directs to Appendices B-E (attached to the previous Declaration), for showing unpredictability in a scaffold-free system in the prior filed art.
33. In paragraph 8, the declaration points to the prior art (Tang and Pereira), asserting that while cell sheets in these references were “evaluated for potential regenerative therapies in different organ systems” like ocular regeneration (Pereira et al), the present invention uses “cell sheets as a neurotrophic factor delivery system”, which would not have been obvious as it was not known “if stem cells could produce neurotrophic factors at the same therapeutic levels when cultured to confluence and subsequently ….relative to sub-confluent cells”; and whether “NTFs could effectively be released from the cell sheets ….or rather remain bound to the extracellular matrix of the cell sheet”.
34. In paragraphs 9, 10 and 11, the declaration concentrates on Nagashima teachings. Paragraph 9 states that the reference does not provide evidence to the contrary that FGF2 addition to a cell culture “would increase cellularity in a cell sheet”. Paragraph 10 states that Nagashima did not culture the DPSCs in a scaffold-free system, the cells were “cultured to sub-confluence” and cell sheets were not formed. The declaration adds that the medium was supplemented with FGF2 during cell sheet formation in the claimed invention, wherein FGF2 treatment unexpectedly increased the cell number within the cell sheets that “subsequently had increased NTF bioactivity”, and this effect was unexpected based on Nagashima teachings.
35. Paragraph 11 of the declaration asserts that the present work (including Appendix F presented with the previous declaration) with neural crest-derived stem cells showed unexpected results. The paragraph adds that even though DPSCs have been known to be potential NTF source, and cell sheet technology is applied to organ system regenerative therapy, the instant claims directed to “addition of FGF2, and the effect of FGF2 on at least cellularity in the culture” was unpredictable based on Nagashima teaching.
36. Paragraph 12 of the declaration summarizes the inventive method of “generating scaffold-free cell sheets from neural crest-derived stem cells” that provides “a superior product, with unexpected properties”, which would not be reasonably expected by a skilled artisan at the time of filing.
Response to the declaration
37. The Syed declaration is fully considered, however, is insufficient to overcome the rejections of claims under 35 USC 103 for reasons described below.
38. The statement (paragraph 4) about lack of predictability in Pereira teachings is considered, but not found to be persuasive as Pereira et al teach the formation of cell sheet by DPSCs after reaching confluence (Figure 1(B)), wherein the cells were seeded at a density of 2 x 106 cells (Methods, para 2). It was stated in the rejection that Pereira et al do not teach FGF2, which was taught by the other cited reference (Nagashima), showing that FGF2 stimulated DPC-induced regeneration of axons and locomotor function in a SCI rat model. The assertion that at the time of filing “no one …. would have considered the effect that FGF2” has on cellularity and cell sheet formation is not found to be persuasive. Not only did the cited art in combination render the effect of FGF2 as obvious for reasons presented in the rejection, but also the prior art was well aware of the same on cell sheet formation in a scaffold-free system. For example, Itokazu et al (Cartilage 7: 361-372, 2016) teach that scaffold-free cell sheets from human BMSCs (hBMSCs) are successfully used for regeneration of osteochondral defects, wherein the cell sheet is generated after culturing the stem cells with FGF2 (Abstract; Mat Meth para 3), the cell-sheet having a cell density (cellularity) of 1.86 x 106/sheet (Figure 1(3)). The reference concludes that FGF2 enhances the proliferative and chondrogenic differentiation capacity of BMSC, suggesting that said conditions provide stable scaffold-free cell sheets that are useful for treatment (page 370, Conclusions). It is noted that the instant specification teaches that culturing with FGF2 produces a cell sheet containing approximately 2 million cells (2 x 106), which is comparable to the cell density in the prior art. The effect of FGF2 on cellularity and cell sheet formation was, therefore, predictable. Moreover, the instant claims do not recite limitations pertaining to “cellularity", or cell density.
39. The arguments set forth in paragraph 5 of the declaration, mainly directed to Nosrat teachings, are fully considered. Nosrat teaches subculturing of the DPCs after these reached confluency (page 121, col 2, para 2), and that RNA was isolated after growing the sub-cultured cells for at least 4 weeks (page 121, col 2, para 4), i.e., the reference teaches the degree of confluency at the time of culture and RNA isolation. Even though Nosrat teaches that the DPSCs of the co-culture experiment had not reached confluency, Nosrat discloses exposing the neural tissue to the neurotrophic factors produced by the DPCs for a time sufficient to produce neurite outgrowth (as required by claim 1, step 2; and as stated in the rejection). Nosrat also showed that DPSC transplantation into spinal cord resulted in an increased number of surviving motoneurons (also stated in the rejection). Since Nosrat teaches that DSCs secrete NTFs, which result in neurite outgrowth, the reference is relevant for demonstrating obviousness and predictability of the method as claimed. Nosrat teaches culturing of DSC post-confluency in most experiments. Even though Nosrat states that the cells of the co-culture study had not reached confluency, the cells are still shown to produce neurite extension as instantly claimed. The effect of confluency on in vitro differentiation and stem cell (BMMSC) properties was taught by Faten et al (IJHOSCR 11: 121-132, 2017) (submitted by Applicant as an Appendix with the previous Declaration, reference to which was made in paragraph 7 of the present Declaration). Using bone marrow mesenchymal stem cells (BMMSC) for osteogenic differentiation, Faten et al show that an 80% or even 100% confluency is acceptable for maximum expansion with high cell density (Abstract; Figure 2A; Conclusion), and the maximum stem cell proliferation was observed at 80% confluence (Figure 3A; page 125, para spanning cols 1, 2). Again, the instant claims do not recite any requirement for "confluency", or the effect of confluency on neurite outgrowth.
40. The argument that Nosrat does not teach cell sheet is acknowledged. However, cell sheet was taught by Pereira. The allegation/comment that Nosrat does not teach scaffold for culture is also considered. Applicant is right. The reference does not have any mention of scaffold, or using any type of scaffold in the culture, which would understandably imply culturing "without a scaffold", absent evidence to the contrary.
41. The remarks about Lui teachings (US 8945536; 2015) in paragraph 6 of the declaration are fully considered. The argument that it was unpredictable that any given stem cell would be "suitable for formation of cell sheets", based on Lui et al showing that TDSCs had better cell sheet formation, is not persuasive. Fig 8A (as Applicant stated) description states that the cellularity of the cell sheet formed by TDSCs and BMSCs was high (col 7, lines 25-28). Since Lui successfully teaches the formation of cell sheet using different stem cells and further explicitly state that the cellularity was high in the studied cell types, Applicant's arguments that it was unpredictable that any given stem cell would be "suitable for formation of cell sheets", based on Lui et al showing that TDSCs had better cell sheet formation, is therefore, not persuasive. Lui et al does not teach away from the use of BMSC. The “prior art’s mere disclosure of more than one alternative does not constitute a teaching away from any of these alternatives because such disclosure does not criticize, discredit, or otherwise discourage the solution claimed….” In re Fulton, 391 F.3d 1195, 1201, 73 USPQ2d 1141, 1146 (Fed. Cir. 2004). See also MPEP § 2123(II).
42. The unpredictability judged from Lui teachings is also not persuasive based upon knowledge in the prior art. The credibility of using BMSC derived cell sheets for therapeutic purpose is evidenced in the prior art (e.g. Itokazu et al) stated above. Moreoever, the present claims do not require determination of a “better” cell sheet.
43. Paragraph 7 remarks directed to unpredictability using a scaffold - free system prior to filing of instant application, and referring to "Appendices B-E" attached with the earlier Declaration dated 11/24, are fully considered. The references have been considered; however, the teachings are not persuasive to establish unpredictability of using a scaffold-free system, prior to instant application filing for the below stated analysis. The relevant teachings of the four references are summarized as follows:
Noda et al (2019) teach that a greater DPSC density showed higher osteogenic differentiation potential (page 5, para 2), however, do not teach cell sheet formation.
Kawashima et al (2017) teach that dense cell culture condition promotes osteogenic differentiation, and cell density during culture, changes DPMSC properties (Conclusion). The reference, however, does not teach using a cell sheet.
Lam et al (2019) teach a microcarrier scaffold during culture (page 633, col 1. para 5), and hence is not pertinent.
Faten et al (2017) teach the effect of confluence on in vitro differentiation and bone marrow mesenchymal stem cells’ (BMMSC) properties, showing that an 80% or even 100% confluency is acceptable for maximum expansion with high cell density (Abstract; Figure 2A; Conclusion). The reference does not mention a cell sheet.
While the references do not teach using a scaffold-free cell sheet for culture, as in present claims, the references establish that culture conditions like cell density, confluence, temperature, are critical elements for cell sheet production and cellular differentiation, none of which are presented in the instant claims. Nonetheless, the cited art teaches or suggests these conditions, as stated in the previous paragraphs. Since the combination of cited art renders obvious the recited method of culturing DPSCs with FGF2 in a scaffold-free culture to produce a scaffold free cell sheet secreting NTFs or paracrine factors, which can be used for organ reconstruction, the combined teachings provide sufficient evidence that the scaffold-free system was reasonably expected to be predictable. Obviousness does not require absolute predictability, only a reasonable expectation of success, i.e., a reasonable expectation of obtaining similar properties. See, e.g., In re O'Farrell, 853 F.2d 894, 903, 7 USPQ2d 1673, 1681 (Fed. Cir. 1988).
44. The statement of paragraph 8 of the declaration, arguing that Tang and Pereira only teach cell sheets for organ regeneration, not for “neurotrophic factor delivery system” as used in the present application, is considered. As stated above, the cited art (Nosrat) demonstrates neurotrophic factors are secreted by DPCs that results in neurite outgrowth and regeneration, thereby evincing that DPCs are capable of delivering such factors. Moreover, the prior art (Pereira) teaches that the benefits observed after transplantation of DPCs were due to secretion of paracrine factors. Therefore, the capacity of neural crest-derived cells and neural crest-derived cell sheets to release neurotrophic factors was known and described in the cited prior art references. Since the prior art NTFs (associated with DPCs or cell sheet) are shown to be effective in neurite growth and regeneration, it would have been reasonably expected that the NTFs are effectively released from the cells/cell sheet. Please note that the claims only require that “the neural crest-derived stem cells …..produce …neurotrophic factors”. Since the cited art (Pereira and Nosrat) teach that the stem cells produce NTFs, the factors are effectively released for further action (neurite outgrowth and regeneration), and not bound to the ECM, absent evidence to the contrary.
45. It is to be noted that both the “organ regeneration” and “neurotrophic factor delivery system” are alleged to be intended uses of the claimed method comprising essentially of two active steps - i) culturing neural crest-derived stem cells without scaffold, and with FGF2; ii) exposing a neural tissue comprising neuron to one or more NTFs produced by the NCs for a time sufficient to produce neurite extension and outgrowth from the neurons. The argument in paragraph 8 of the declaration, asserting non-obviousness of the present application since it uses “cell sheets as a neurotrophic factor delivery system”, instead of regenerative therapies taught in the cited art, is not found to be persuasive. The statement seems to be claiming a surprising discovery involving a novel property of cell sheets. However, the claiming of a new use, new function or unknown property which is inherently present in the prior art does not necessarily make the claim patentable. In re Best, 562 F.2d 1252, 1254, 195 USPQ 430, 433 (CCPA 1977).
46. The claim limitations following “wherein” and “thereby” clause at the end of sections 1 and 2 of claim 1, only recite a result of the preceding method step, but not a step that is to be performed by the artisan. Upon performing the active steps (stated above), one will necessarily have achieved production of NTFs from the scaffold free tissue structure, which would produce neurite extension. Regardless, these resultant effects are also evidenced by the cited prior art references. It is repeated that the claims only recite two active method steps, and no further steps reciting e.g. determining or measuring NTFs, detecting neurite extension, etc. are presented.
47. The remarks in paragraphs 9-11 (directed to Nagashima teachings), are fully considered. Nagashima et al teach that FGF2 is a growth factor that promotes the proliferation of multiple cell types like DPSC (page 2, para 2). The reference also teaches that DPCs cultured to confluence with FGF2 showed long, spindle-shape morphology as compared to subconfluent cells (Results, para 1; Fig 1). This proves that it was known in the art FGF2 promotes the proliferation of DPSC (increase cellularity), and induces axonal regeneration in the injured spinal cord (page 2, para 6). Since there is no mention of using a scaffold during culture of DPCs, the reference obviously indicates a “scaffold-free” culture, contrary to the allegation that the culture “was not performed in a scaffold-free system”. Paragraph 11 statement pertaining to the effect of FGF2 on the cellularity in the culture is considered and addressed above. It is repeated that Nagashima teaches that FGF2 promotes the proliferation of DPSC (increase cellularity), and induces axonal regeneration in the injured spinal cord. Applicant's argument that Nagashima does not teach cell sheet is acknowledged. However, this is taught by Pereira in a 103 setting.
48. Applicant’s assertion of unexpected results shown in Appendix F (Applicant’s work) is considered, however, the effect of FGF2 was shown to be expected from the teachings of Nagashima for reasons explained in the prior paragraphs and in the rejection. Moreover, the knowledge of FGF2 effect on culture cellularity was also evidenced by the earlier presented teachings of Itokazu et al.
49. The summary presented in paragraph 12 asserting unexpectedness of “generating scaffold-free sheets from neural crest-derived stem cells” which provide “a superior product, with unexpected properties”, at the time of filing, is considered, but not found to be persuasive. The combination of the above references proves that the knowledge and expertise for the claimed method for culturing NC without scaffold, and with FGF2; and exposing a neural tissue comprising neuron to one or more NTFs produced by the NCs for a time sufficient to produce neurite extension and outgrowth from the neurons was known in the art and the results were expected to be successful. The prima facie obviousness of the claimed invention in view of the combined references, therefore, provides sufficient reasoning, and nullifies Dr. Syed’s allegations of the improper teachings in the individual references. The declaration’s assertion of unexpected results does not overcome the rejection because of obvious expected properties taught in the prior art, either explicitly or implicitly. “Where the unexpected properties of a claimed invention are not shown to have a significance equal to or greater than the expected properties, the evidence of unexpected properties may not be sufficient to rebut the evidence of obviousness”. In re Nolan, 553 F.2d 1261, 1267, 193 USPQ 641, 645 (CCPA 1977). That is, the alleged unexpected results are actually expected from the prior art.
50. The declaration presents arguments against each reference on an individual basis, despite the fact that the art is used in combination to show obviousness of the recited claimed method. However, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., Inc., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
51. In view of the foregoing, the declaration in totality is found to be ineffective to withdraw the pending rejections.
Applicant’s Remarks:
52. Applicant’s arguments are primarily similar to the statements in the Syed declaration stated above. Referring to paragraph 8 of the declaration, Applicant adds that the cited art does not teach or suggest that cell sheets can produce NTFs that would effectively be released as free NTFs, and not be trapped in ECM. Applicant directs to the teaching in the instant application (paras 98-103; Figs 3-4). Applicant concludes that since “the weight of evidence of record shows that the claims define over the cited art of record”, the rejections must be withdrawn.
53. Applicant’s arguments are fully considered, however, are not found to be persuasive for reasons presented in response to the declaration. Applicant’s pointing to the specific portions of the instant disclosure is also considered. Paragraphs 98-103 of the specification describe the measurement of cell number and NTF gene expression, and figures 3-4 show a significant effect of FGF2 on cell numbers and NTF expression. As stated above in response to paragraph 8 of the declaration, the prior art NTFs (associated with DPCs or cell sheet) are shown to be effective in neurite growth and regeneration, therefore, it would be obvious that the NTFs are effectively released from the cells/cell sheet. Please note that the claims only require that “the neural crest-derived stem cells …..produce …neurotrophic factors”. Since the cited art (Pereira and Nosrat) teach that the stem cells produce paracrine factors or NTFs which are biologically effective, the factors would necessarily be released for exerting the activity (neurite outgrowth and regeneration), and not be bound to the ECM, absent any evidence to the contrary. Additionally, as stated above, it was known in the art FGF2 promotes the proliferation of DPSC (increase cellularity or cell number), and induces axonal regeneration in the injured spinal cord (Nagashima et al page 2, para 6).
54. Applicant’s arguments are not found to be persuasive, because the arguments rely on particular distinguishing features that are not recited in the claims. The declaration and Applicant’s remarks are arguing limitations not required by the instant claims. The cited art is largely disputed on the basis of cellularity level, confluency, degree of confluency, effect of FGF2 on cell number, NTF release, etc.; however, none of these elements are recited or required the claims. The claims broadly require culturing neural crest-derived stem cells (NC) without scaffold, and with FGF2; and exposing a neural tissue comprising neuron to one or more NTFs produced by the NCs for a time sufficient to produce neurite extension and outgrowth from the neurons. The declaration and Applicant’s remarks refer to the teachings in the instant application to assert discrepancies in the cited art. Applicant is reminded that narrow limitation contained in the specification cannot be inferred in the claims where the elements not set forth in the claims are linchpin of patentability. See In re Philips Industries, Inc. v. State Stove & Mfg. Co., 522 F.2d 1137, 186 USPQ 458 (CA6 1975), 237 PTJA A-12. While the claims are to be interpreted in light of the specification, it does not follow that limitations from the specification may be read into claims. On the contrary, claims must be interpreted as broadly as their terms reasonably allow. See Ex parte Oetiker, 23 USPQ2d 1641 (BPAI, 1992). Applicant is reminded that the claims define the subject matter of his invention and that the specification cannot be relied upon to read limitations into the claims.
55. The rejection is therefore maintained.
New rejection
Double Patenting
Non-Statutory
56. 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).
57. 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).
58. 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.
59. 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.
60. Claims 1-2, 4-11 and 22 are provisionally rejected on the ground of nonstatutory obviousness-type double patenting as being unpatentable over claims 1-3, 5, 7, 9, 14, 16, 19 of co-pending application number 17/909,263 in view of Nagashima et al (2017) and Wei et al (2012), and as evidenced by Stanko et al (Stem Cells Intl 2018: 1-8, 2018).
Although the conflicting claims are not identical, they are not patentably distinct from each other because in each case the claims are directed to a method comprising culturing neural crest stem cells or dental pulp cells on a scaffold-free substrate, wherein the cells produce a NTF and a scaffold-free cell sheet.
The only differences between the two sets of claims are:
i) Instant claims recite the use of FGF2 and ascorbic acid, while the ‘263 application claims do not have this limitation. However, the addition of FGF2 and ascorbic acid would be obvious in view of the teachings of Nagashima et al and Wei et al respectively, for reasons stated above. The use of FGF2 (1-50 ng/2.5ml, i.e. 0.4-20 ng/ml) and ascorbic acid for cell sheet formation is also taught in the ‘263 PGPB (para 0074).
ii) Claims of the ‘263 application recite further steps directed to assembling (using) the cell sheet for formation of nerve conduit, which is absent in the present claims. However, since both sets of claims recite the formation of cell sheet, and “comprising” (the steps), instant claims are rendered obvious over the ‘263 claims. It is noted that “comprising” is a term of art used in claim language which means that the named elements are essential, but other elements may be added and still form a construct within the scope of the claim; and leaves "the claim open for the inclusion of unspecified ingredients even in major amounts". Invitrogen Corp. v. Biocrest Manufacturing, L.P., 327 F.3d 1364, 1368, 66 USPQ2d 1631, 1634 (Fed. Cir. 2003) ("The transition ‘comprising’ in a method claim indicates that the claim is open-ended and allows for additional steps.") [MPEP 2111.03(I)].
iii) The ‘263 claims recite specific NTFs, while instant claims recite one or more NTFs. Instant claims reciting a genus are, therefore, obvious over the ‘263 claims. Moreover, the production of NTFs (BDNF, GDNF) by DPCs would be obvious over the teachings of Nosrat et al (page 123).
iv) The ‘263 application claim 9 recites different stem cell types, while instant claims only recite neural crest stem cells and DPCs. However, as evidenced by Stanko et al, DPCs (or DPMSCs – dental pulp MSC) are mesenchymal stem cells, that are neural crest derived cells (Abstract; page 2, col 1, last para).
v) ‘263 claims recite culturing cells to confluence or over-confluence, while instant claims do not recite this limitation. However, this is obvious in view of Pereira et al for reasons stated in para 9 of this office action
61. This is a provisional obviousness-type double patenting rejection because the conflicting claims have not in fact been patented.
Conclusion
62. No claims are allowed.
63. Any inquiry concerning this communication or earlier communications from the examiner should be directed to Aditi Dutt whose telephone number is (571)272-9037. The examiner can normally be reached on M-F 9:00am-5:00pm.
64. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
65. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Jeffrey Stucker, can be reached on 571-272-0911. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
66. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/A. D./
Examiner, Art Unit 1675
16 August 2026
/KIMBERLY BALLARD/Primary Examiner, Art Unit 1675
Prosecution Insights