DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 9/22/2025 has been entered.
Claims 1-8, 11-13, 19-21, 23-24, 26, 29 and 33-34 have been canceled, claim 38 is newly added, claims 32, 35 and 37 have been withdrawn from consideration as being drawn to non-elected subject matter, and claims 9-10, 1418, 22, 25, 27-28, 30-31 and 38 have been considered on the merits. All arguments have been considered.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
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 9-10, 14-17, 28, 30-31 and 38 are rejected under 35 U.S.C. 103 as being unpatentable over Sturgeon et al. (2014, Nature Biotechnology; IDS ref.) in view of Valamehr et al. (WO 2016/123100; of record), Mantalaris et al. (US 2008/0159994 A1) and Osei-Sarfo et al. (2014, Nature Biotechnology).
Sturgeon et al. teach a method of differentiating human pluripotent stem cells into definitive hematopoietic stem cells (HSCs) by regulating the Wnt-b-catenin signaling pathway (Abstract). Sturgeon et al. teach the use of hESC lines and human iPS cells (p.10, Methods). Sturgeon et al. teach that the addition of the GSK-3 inhibitor CHIR99021, a Wnt agonist, during the mesoderm specification stage, i.e. day 2-3, in the culture inhibited KDR+CD235a+ population (i.e. inhibit primitive hematopoiesis) but promoted KDR+CD235a- population (i.e. promote definitive hematopoiesis) and differentiation into definitive HSCs (p.5, 2nd para.; Fig. 4E). Sturgeon et al. teach that SB-431542, an Activin-signaling antagonist, behaved the same way as CHIR99021 in promoting definitive hematopoiesis (p.7, 2nd para.; Fig. 4E). Sturgeon et al. teach that hPSC are differentiated as embryoid body (p.2, Results; Fig. 4).
Sturgeon et al. do not teach that both CHIR99021 and SB-431542, an ACTIVIN antagonist, are present in the culture medium for PSC, however, it would have been obvious to a person skilled in the art to use both CHIR99021 and SB-431542 in the method of Sturgeon et al. since each compound is known to enhance/promote definitive hematopoiesis. It is well established that duplicating components with similar functions within a composition is obvious; see In re Harza, 274 F.2d 669, 124 USPQ 378 (CCPA 1960) and M.P.E.P. § 2144.04.
Furthermore, Valamehr et al. teach that hematopoietic differentiation was initiated by switching the culture medium to iHSC-A, and the culture was switched to iHSC-B at 48 hr (day 2) post the initiation of differentiation (para. 281). Th iHSC-B medium contains CHIR999021 and SB431542 (see Fig. 1).
It would have been obvious to a person skilled in the art to use both CHIR999021 and SB431542 as taught by Valamehr et al. for the method of Sturgeon et al. A person of ordinary skilled in the art would have been motivated to do so because not only the teaching of Sturgeon et al. that each of CHIR99021 and SB-431542 individually had the effect of these agents producing definitive hematopoietic progenitors (see Fig. 4E) but also the teaching of Valamehr et al. using both agents for the purpose of differentiating PSCs into hematopoietic differentiation.
Regarding the limitations directed to the medium comprising the WNT agonist and the ACTIVIN antagonist increasing HOXA gene expression, the increased HOXA gene expression being relative to a cell not cultured in a medium comprising the WNT agonist and the ACTIVIN antagonist (claim 9); type of HOXA gene (claim 10) or the definitive HSPC being capable of producing a SOX17+ blood vessel cell (claim 28), Sturgeon et al. do not particularly teach the limitation. However, it is submitted that these limitations are directed to the result of culturing PSC in the presence of both CHIR99021 and SB-431542, and the modified method of Sturgeon et al. as proposed (i.e. both CHIR99021 and SB-431542 in the medium) would inherently produce the same result of increasing HOXA gene expression, and the claimed HOXA gene and the definitive HSPC capable of producing the SOX17+ blood vessel cell.
Regarding the limitation directed to the “at about day 2 to day 4”, Sturgeon et al. teach that CHIR99021 or SB431542 is present day 2-3 (p.7, 2nd para.; Fig. 1A; Fig. 4E).
Regarding the concentration of CHIR99021 or SB431542 (claims 15 and 17), Sturgeon et al. teach that the concentrations of CHIR99021 and SB-431542 is 3 M and 6 M, respectively (p.10, Methods). While Sturgeon et al. do not particularly teach the concentration of SB431542 being 2-5 M, however, Valamehr et al. teach the concentration of SB-431542 at 0.1-15 mM in the culture medium for obtaining hemogenic endothelium from mesodermal cells (p.50-51, Table 2). Valamehr et al. teach a method of differentiating pluripotent stem cells including induced pluripotent stem cells (iPSCs) into hematopoietic lineage through definitive hematopoietic stem cells (paras. 2, 7-8). Valamehr et al. teach that hematopoietic differentiation was initiated by switching the culture medium to iHSC-A, and the culture was switched to iHSC-B at 48 hr (day 2) post the initiation of differentiation (para. 281). The iHSC-B medium contains CHIR99021 and SB431542 (see Fig. 1).
Therefore, it would have been obvious to a person skilled in the art to use the known concentration of SB-431542 taught by Valamehr et al. for the method of Sturgeon et al. with a reasonable expectation of success.
Regarding the newly added limitation directed to the medium being added with a retinoid or retinoic acid analogue at day 2 or day 3 (claim 9), Sturgeon et al. in view of Valamehr et al. do not teach the limitation.
Mantalaris et al. teach that retinoic acid stimulates mesoderm formation (para. 164).
Sturgeon et al. teach that Wnt inhibition is mediated by retinoic acid (p. 9, 2nd para.). Sturgeon et al. also teach that transient Wnt inhibition via Er71 expression is required for specification of murine primitive hemangiogenic mesoderm at a stage comparable to that evaluated in their study in the human cultures (p.9, 2nd para.), and
after formation of a primitive-streak-like population, KDR+CD235a+ mesoderm fated to the primitive hematopoietic lineage is specified by the combination of Activin-nodal signaling and Wnt inhibition (Fig. 5, legend).
Osei-Sarfo et al. teach retinoic acid suppresses the canonical Wnt signaling (see entire document), and the Wnt agonist utilized by Sturgeon et al., i.e. CHIR99021, is a canonical Wnt signaling agonist (see Fig. 3 of Sturgeon et al.).
It would have been obvious to a person skilled in the art to use retinoic acid at day 2 or 3 of the process in order to stimulate mesoderm formation as taught by Mantalaris et al. by inhibiting Wnt signaling. A person of ordinary skilled in the art would have been motivated to do so because retinoic acid would be utilized in order to stimulate mesoderm formation from EBs of ES cells as taught by Mantalaris et al. and this can be carried out by using retinoic acid which inhibits canonical Wnt signaling as taught by Sturgeon et al. and Osei-Sarfo et al. As the process of differentiation shown in Fig. 5 of Sturgeon et al. indicates at day 3, Thus, day 3 of differentiation as shown in Fig. 5 is considered to the same as mesoderm formation.
Regarding claim 32 directed to the retinoid or retinoic acid analogue excluding all trans retinoic acid, Sturgeon et al. in view of Valamehr et al. and Mantalaris et al. do not teach the negative limitation. However, retinoic acid taught by Sturgeon et al. or Mantalaris et al. would encompass all trans retinoic acid (ATRA) as well as non-ATRA such as 9-cis retinoic acid and 13-cis retinoic acid known in the art (see , and thus, it would have been obvious to a person skilled in the art to choose any available retinoid or retinoic acid analogue including those non-ATRA for the method of Sturgeon et al. in view of Valamehr et al. and Mantalaris et al. with a reasonable expectation of success.
Therefore, the invention as a whole would have been prima facie obvious to a person of ordinary skill before the effective filing date of the claimed invention.
Claims 18 and 27 are rejected under 35 U.S.C. 103 as being unpatentable over Sturgeon et al. in view of Valamehr et al., Mantalaris et al. and Osei-Sarfo et al. as applied to claims 9-10, 14-17, 28, 30-31 and 38 above, and further in view of Ng et al. (2008, Nature Protocols; IDS ref.), Pick et al. (2007, Stem Cells; IDS ref.) and Cerdan et al. (2012, Stem Cells and Development; of record)
Regarding the medium further comprising BMP4, VEGF, SCF, ACTIVIN A, FGF2 for about day 0 to about day 4 (claim 18), Sturgeon et al. in view of Valamehr do not teach the limitations.
Regarding BMP4, VEGF and SCF, Ng et al. teach a method of differentiating human ESCs into hematopoietic lineage by using spin embryoid bodies (EBs) in APEL medium (see abstract; p.771; RE: claim 27). Ng et al. teach that BMP4, VEGF, SCF are used to induce hematopoietic mesoderm differentiation (step 6, p.771). This step of mesoderm differentiation is understood to correlate the first 4 days of differentiation taught by Sturgeon et al. (see Fig. 5; day 0-3) since KDR+CD235a+ and KDR+/CD235a- are two mesoderm populations (i.e. primitive and definitive progenitors, respectively).
Regarding FGF2, Sturgeon et al. teach the use of bFGF in the initial EB differentiation (see Fig. 1A). Pick et al. teach the combination of BMP4, VEGF, SCF and FGF2 for the method of differentiating human ESCs into hematopoietic cells using a serum- and stromal-free “spin EB” differentiation system (see Abstract).
Regarding Activin A, Cerdan et al. teach that Activin A promotes hematopoietic fated mesoderm development in human ESCs (abstract).
Based on the teachings from Ng et al., Pick et al., and Cerdan et al., it would have been obvious to a person skilled in the art to use BMP4, VEGF, SCF, FGF2 and Activin A for a method of differentiating hematopoietic lineage cells from PSCs taught by Sturgeon et al. in view of Valamehr et al. Once PSCs are cultivated to induce hematopoietic differentiation with the factors taught by Ng et al., Pick et al., and Cerdan et al., one skilled in the art would recognize that the addition of CHIR99021 and/or SB431542 as taught by Sturgeon et al. at day 2-3 would promote toward definitive hematopoiesis over primitive hematopoiesis.
Regarding the concentrations of the components of the medium disclosed in claim 18, Sturgeon et al. do not teach the limitation.
Valamehr et al. teach that iHSC-A medium comprises BMP4, bFGF, CHIR99021 and iHSC-B medium comprises BMP4, bFGF, CHIR99021 and SB431542, and the use of iHSC-A medium is first 2 days, iHSC-B medium is next 48 hours, and then iHSC-C medium is used for day 4-5 (Fig. 1; para. 281). Thus, the first 4 days of culturing is used with iHSC-A and -B media for the method of Valamehr et al. The iHSC-A and -B media are the same except iHSC-B contains SB431542 (see Table 1-2). Valamehr et al. teach that after 4 days of iHSC-A and iHSC-B media, hemogenic endothelium is obtained from iPSCs via mesodermal differentiation. Valamehr et al. teach that the culture medium of the invention comprises one or more of the cytokines or growth factors including bFGF, VEGF, SCF, etc. (para. 136). Valamehr et al. teach that iHSC-A and -B media contain BMP4 at 0.05-15 ng/ml, bFGF (FGF2) at 0.2-50 ng/ml and CHIR99021 at 0.1-15 mM (Table 1 and 2). While the tables of Valamehr et al. do not particularly teach other ingredients and their concentrations, the use of other cytokines and/or growth factors are obvious as discussed above, and thus, the concentrations of the other ingredients would be used at the concentrations disclosed in their method. For example, VEGF is utilized at 0.5-125 ng/ml; SCF at 2-500 ng/ml in the iHSC-C medium (Table 3), and thus, one skilled in the art would try the same concentration range for these components when they are used in iHSC-A and/or iHSC-B medium with a reasonable expectation of success.
Therefore, the invention as a whole would have been prima facie obvious to a person of ordinary skill before the effective filing date of the claimed invention.
Claims 22 and 25 are rejected under 35 U.S.C. 103 as being unpatentable over Sturgeon et al. in view of Valamehr et al., Mantalaris et al. and Osei-Sarfo et al.as applied to claims 9-10, 14-17, 28, 30-31 and 38 above, and further in view of Daley et al. (US 2019/0119643; of record), Ng et al. (supra), Yamanaka et al. (US2016013798; of record), Slukvin (2013, Blood; of record), and Kennedy et al. (2007, Blood; IDS ref.)
Regarding the limitation of claim 22 directed to the medium comprising BMP4, VEGF, SCF, FGF2 and IGF2 at about day 5, Sturgeon et al. in view of Valamehr et al. do not teach the limitation.
Regarding the limitation of claim 25 directed to transferring the PSC to a culture surface comprising an extracellular matrix protein at about day 7 and culturing the PSC adherently in a medium comprising VEGF, SCF, FGF2, IGF2, IL-6, TPO, FLT3L, Sturgeon et al. in view of Valamehr et al. do not teach the limitation.
Yamanaka et al. teach a method of differentiating hematopoietic stem cells from pluripotent stem cells using 4 steps:
(i) Day 0 to Day 1 utilizing a medium comprising BMP-4 (EB formation);
(ii) Day 1 to Day 4 utilizing a medium comprising BMP-4 and bFGF (mesoderm formation);
(iii) Day 4 to Day 8: utilizing a medium comprising VEGF, bFGF, IL-6, IL-3, SCF, and FLt3L (specialization and development into hematopoietic progenitor cells); and
(iv) Day 8 to Day 15: utilizing a medium comprising VEGF, EPO, TPO, SCF, FLT3L, IL-6, IL-11, and IL-3 (maturation and expansion into hematopoietic progenitor cells); and IGF2 can be added in any step (paras. 167-172, 174-177; Example 2).
One skilled in the art would recognize that the steps (i)-(iv) of Yamanaka et al. listed above are correlated with steps (i)-(iv) of Sturgeon et al.
Sturgeon et al. teach the following steps:
(i) EB stage (day 0-2);
(ii) KDR+/CD235a+/- mesoderm stage (day 2-3);
(iii) CD34+/CD235a+/- stage (day 4-8); and
(iv) CD34+/CD43- hemogenic endothelium stage (day 9 and up) to definitive hematopoiesis (see Fig. 5; reproduced below).
Therefore, it would have been obvious to a person skilled in the art to use the culture medium specifically defined in the steps (i)-(iv) taught by Yamanaka et al. for the method steps of Sturgeon et al. in view of Valamehr et al. This is because one skilled in the art would understand that the steps of Sturgeon et al. correspond to the steps of Yamanaka et al., and thus, the culture medium used in the each step of Yamanaka et al. would be used in the corresponding steps of the method taught by Sturgeon et al. with a reasonable expectation of success. By using the medium used in step (iii) of Yamanaka et al. for the method of Sturgeon et al., the component of VEGF, SCF, and FGF2 in the medium as claim 22 would be met. Regarding IGF2, Yamanaka et al. teach that IGF2 is added to the culture medium in order to promote induction of differentiation into hematopoietic stem/progenitor cells, and it can be added throughout all steps (para. 96).
It is noted that the starting points of the step disclosed in claim 22 and 25, i.e. about day 5 and about day 7, would be interpreted broadly and the step (iii) (day 4-8) and the step (iv) (day 9 and up), respectively, would meet the limitations.
Sturgeon et al. in view of Valamehr et al. and Yamanaka et al. do not teach the use of BMP-4 in step (iii), i.e. day 5 as in claim 22.
However, Kennedy et al. teach that BMP-4 is essential for hemangioblast development from EBs derived from human ES cells (abstract; p.2685, 1st col.).
It would have been obvious to a person skilled in the art to use BMP-4 in the step (iii) of Sturgeon et al. in view of Valamehr et al. and Yamanaka et al. since Kennedy et al. teach that BMP-4 is essential in forming hemangioblasts. This is because one skilled in the art would recognize that the step (iii) of Sturgeon et al. in view of Valamehr et al. and Yamanaka et al. is for generation of hemangioblast or hematovascular specification since Sturgeon et al. teach that hemangioblast potential is tested KDR+ populations (p.15-16; Fig. 1), which are cells formed in step (ii) of Sturgeon et al.
Regarding the components of claim 25, i.e. step (iv), Sturgeon et al. in view of Valamehr et al. and Yamanaka et al. teach VEGF, EPO, TPO, SCF, FLT3L, IL-6 and IL-3 and IGF2 (see above; para. 80), however, they do not teach the use of FGF2 in step (iv).
Daley et al. teach the use of bFGF along with TPO, EPO, IL-3, IL-6, SCF, VEGF and BMP4 in the endothelial-to-hematopoietic transition (EHT) (para. 263, 391-392).
Thus, it would have been obvious to a person skilled in the art to use bFGF taught by Daley et al. in the step (iv) of Sturgeon et al. in view of Valamehr et al. and Yamanaka et al. with a reasonable expectation of success. This is because one skilled in the art would recognize that the step (iv) of Sturgeon et al. corresponds to the EHT step taught by Daley et al.
Regarding the limitation directed to transferring the PSC to a culture surface comprising an extracellular matrix protein at about day 7 (claim 25), the cited references do not teach the limitation.
Ng et al. teach the step of transferring the EB to a culture plate pre-coated with gelatin or ECM components, and the medium is supplemented with SCF, VEGF, IL-3, IL-6, TPO and EPO (step 16, p.772).
Regarding the concentrations of the components disclosed in claims 22 and 25, Yamanaka et al. teach BMP4 at 1-100 ng/ml (para 82), VEGF at 1-100 ng/ml (para. 84), SCF at 1-500 ng/ml (para. 88), bFGF at 1-100 ng/ml (para. 83), and IGF2 at 1-500 ng/ml (para. 111), IL-6 at 1-100 ng/ml (para. 85), TPO at 1-100 ng/ml (para. 91), FLT3L at 1-500 ng/ml (para. 89), and EPO at 1-10 U/ml (para. 90).
Therefore, the invention as a whole would have been prima facie obvious to a person of ordinary skill before the effective filing date of the claimed invention.
Response to Arguments
Applicant’s arguments with respect to claim(s) 9-10, 14-17, 28 and 30-31 have been considered but are moot because the new ground of rejection necessitated by the instant amendment. Upon the instant amendment, the claimed method requires the culture medium supplemented with a retinoid or retinoic acid analogue at day 2 or day 3. This new limitation has been addressed by citing new references (Mantalaris et al., Osei-Sarfo et al.; see above), and Yu et al. cited in the claim rejection directed to claim 22, which is canceled now, is no longer applied to the claim rejection.
Conclusion
No claims are allowed.
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/TAEYOON KIM/Primary Examiner, Art Unit 1631