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 .
1. Original claims 1-11 are pending and under examination.
Claim Objections
2. It is suggested that claim 2 be cancelled and its limitations be incorporated into claim 1. The following amendment to claim 1 is suggested:
A method for the in vitro production of red blood cells, comprising the steps of culturing erythroid progenitor cells in a stationary culture until the diameter of the erythroid progenitor cells reaches 10 to 15 µm, and switching to agitation culture after the diameter of the erythroid progenitor cells reaches 10 to 15 µm.
3. Claim 3 should recite:
The method of claim 1, wherein the stationary culture is performed in a bioreactor or an agitator under a hydrodynamic shear stress induced by an agitation speed of less than 30 rpm or a tip speed of less than 0.018 m/s, at a temperature between 20 and 38°C.
4. Claim 4 should recite:
The method of claim 1, wherein the agitation culture is performed under a hydrodynamic shear stress induced by the flow of the culture medium at an agitation speed of 200 rpm to 800 rpm or a tip speed of 0.15 m/s to 0.48 m/s.
5. Claim 6 should recite:
The method of claim 1, wherein the agitation culture results in fully mature red blood cells.
6. Claim 7 should recite:
The method of claim 1, wherein the stationary culture and the agitation culture are performed without supporting stromal cells.
7. Claims 7-9 are objected to because of the recitation “erythrocyte progenitor cells”. Correction to “erythroid progenitor cells” is required.
8. Claim 8 is objected to because of the recitation “the erythrocyte progenitor cells are erythroid cells before enucleation”.
Since the specification discloses that the agitation culture results in enucleation, it is clear that the intended erythroid progenitor cells before enucleation are those transitioning from the stationary to the agitation culture.
Claim 8 should be amended to recite:
The method of claim 1, wherein the erythroid progenitor cells having the diameter of 10 to 15 µm are erythroid progenitor cells before enucleation.
8. Claim 9 recites a Markush group of erythroid progenitors, which include the immature proerythroblasts. It is clear from the specification that the immature proerythroblasts are not subjected to agitation culture. The agitation culture starts late at the basophilic erythroblast stage, when the basophilic erythroblasts start transitioning to proerythroblasts (see Fig. 1).
Consistent with the specification, the following amendment to claim 9 is suggested:
The method of claim 1, wherein the erythroid progenitor cells in the stationary culture are proerythroblasts and basophilic erythroblasts, and wherein the erythroid progenitors in the agitation culture are basophilic erythroblasts, polychromatic erythroblasts, orthochromatic erythroblasts or mixtures thereof.
Claim Rejections - 35 USC § 101
9. 35 U.S.C. 101 reads as follows:
Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title.
10. Claim 11 is rejected under 35 U.S.C. 101 because the claimed invention is directed to a judicial exception without significantly more. The claim(s) recite RBCs, i.e., a product of nature. Since the claim is a product-by-process claim, the judicial exception is not integrated into a practical application. Furthermore, the process steps do not include additional elements that are sufficient to amount to significantly more than the judicial exception because there is no the evidence that producing RBCs by using the claimed method results in RBCs that are any different from their naturally-occurring counterparts. The specification discloses that the RBCs prepared by the claimed method are not functionally different from the control peripheral blood RBCs, exhibit the CD71-/GPA+ phenotype; except that they express both fetal hemoglobin (HbF) and adult hemoglobin (HbA), while the control peripheral blood RBCs only expressed HbA (see Example 3; Fig. 9c).
However, there are naturally-occurring RBCs expressing both HbF and HbA, for example, the naturally-occurring infant RBCs (Bard, J. Clin. Invest., 1973, 52: 1789-1795; see Abstract; p. 1792, Fig. 3) and the adult F-cells (rare RBCs present in blood; Steinberg, Blood, 2014, 123: 481-485; see p. 481, column 1 and column 2, first full paragraph). As evidenced by Rallapalli et al. (Cell and Tissue Res., 2019, 375: 437-449), RBCs exhibit the CD71-/GPA+ phenotype regardless of whether they express HbF or not (see p. 442, paragraph bridging columns 1 and 2 and column 2, first and second full paragraphs).
There is nothing in the claim or specification indicating that the method steps result in RBCs which are any different from the naturally-occurring infant RBCs and/or F-cells. The specification teaches that the stationary culture expands the population of immature erythroid progenitors, while the agitation step results in increased maturation and enucleation rate. There is no evidence in the specification or art indicating that expanding under stationary conditions and/or inducing maturation/enucleation under agitation leads to RBCs which are any different from their naturally-occurring counterparts. The claim does not include additional elements sufficient to amount to significantly more than the judicial exception.
Therefore, the rejection under 35 U.S.C. 101 is appropriate.
Claim Rejections - 35 USC § 102
11. 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 the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
12. Claim 11 is rejected under 35 U.S.C. 102(a)(1) as being anticipated by Steinberg et al. (Blood, 2014, 123: 481-485), as evidenced by Rallapalli et al. (Cell and Tissue Res., 2019, 375: 437-449; cited on the IDS filed on 11/14/2024).
In making this rejection it is noted that, although claim 11 does not recite a phenotype for the claimed RBAs, the specification discloses that they are CD71-/GPA+ and express both HbF and HbA (see Example 3; Fig. 9c).
Steinberg et al. discloses F-cells, naturally occurring and normal adult RBCs expressing both HbF and HbA (see Abstract; p. 481, column 1 and column 2, first full paragraph). As evidenced by Rallapalli et al., RBCs exhibit the CD71-/GPA+ phenotype regardless of whether they express HbF or not (see p. 442, paragraph bridging columns 1 and 2 and column 2, first and second full paragraphs). Thus, Steinberg et al. teach all claim limitations and anticipate the claimed invention.
Claim Rejections - 35 USC § 103
13. 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.
14. Claims 1-3 and 5-11 are rejected under 35 U.S.C. 103 as being unpatentable over Timmins1 (PGPUB 2010/0285586, cited on the IDS filed on 11/14/2024), in view of all Timmins 2 (Tissue Eng. Part C, 2011, 11: 1131-1137), Boehm et al. (J. Immunol. Methods, 2010, 360: 20-29), Wojda et al. (Blood, 2002, 99: 3005-3013), and Yeo et al. (Biophysical Reviews, online 15 August 2019, 11: 873-894).
Timmins1 teaches a method for the ex vivo production of red blood cells (RBCs) from CD34+ cells, the method comprising in order: (1) an expansion phase entailing culturing the CD34+ cells under static conditions for 21 days at 37º C, in an erythroid expansion medium to allow for the optimal expansion of the erythroid progenitors, and (2) a maturation phase starting at culture day 21, entailing the agitation culture of the erythroid progenitors at 25 rpm in a bioreactor at 37º C, in an erythroid maturation medium, where agitation enhances the enucleation rate compared to the static culture; both static and agitation cultures are performed in the absence of stromal cells (claims 1-3 and 6-11) (see [0021]; [0087]-[0089]; [0098]-[0100]; [0107]-[0108]; [0110]; [0117]; [0119]; [0128]; Example 1).
Timmins1 does not teach starting the agitation culture when the erythroid progenitors reach a diameter of 10-15 µm (claims 1 and 2). Timmins1 does not specifically teach the size of the erythroid progenitors at the start of the agitation culture. Timmins2 discloses that expansion for 21 days, as in Timmins1, results in a population of erythroid progenitors of mixed maturity, the majority having a dimeter of ˃10 µm to ˂ 20 µm (see p. 1132; p. 1133, Fig. 1B).
Boehm et al. teach that, during ex vivo erythropoiesis from CD34+ cells, agitation at 20 rpm induces loss of viable cell. Boehm et al. teach that the developmental stages between culture days 8-12 are more sensitive to agitation. Boehm et al. teach that culture days 8-12 are characterized by the presence of a mixed population of CD71+/GPA- and CD71+/GPA+ cells, with CD71+/GPA- cells gradually transitioning to CD71+/GPA+ cells; by culture day 12, the majority of the cells are CD71+/GPA+ (see p. 22; p. 24; Fig. 4a). Wojda et al. teach that the shift from CD71+/GPA- to CD71+/GPA+ cells marks the transition from proerythroblasts to basophilic erythroblasts (see paragraph bridging p. 3006 and 3007; p. 3007, Fig. 1). Furthermore, it was known in the prior art that the proerythroblasts have a size of 20-25 µm, basophilic erythroblasts have a size of 16-18 µm, and that basophilic erythroblasts mature into polychromatic erythroblasts having a size of 12-15 µm (see Yeo et al.; p. 874).
Based on all the teachings above, one of skill in the art would have reasonably concluded that the 21-day population of erythroid progenitors in Timmins1 comprises basophilic erythroblasts, which are sensitive to agitation and would lose viability when agitated at 25 rpm. One of skill in the art would have found obvious to modify the method taught by Timmins1 by starting agitation when the basophilic erythroblasts transition to polychromatic erythroblasts (i.e., when the cells reach a diameter of 12-15 µm), with the reasonable expectation that doing so would result in enhanced RBC yield (claims 8 and 9). By doing so, one of skill in the art would have increased cell density by supplying oxygen and nutrients through the agitation of the medium (claim 5).
The range 12-15 µm taught by the prior art lies within 10-15 µm, and thus, anticipates the range recited in claims 1 and 2.
Thus, the claimed invention was prima facie obvious at the time of its effective filing date.
15. Claims 1-11 are rejected under 35 U.S.C. 103 as being unpatentable over Timmins et al. taken with all Timmins1, Boehm et al., Wojda et al., and Yeo et al., in further view of Bayley et al. (J. Tissue Engineering and Regenerative Medicine, 2018, 12: e368-e378).
The teachings of Timmins1, Timmins2, Boehm et al., Wojda et al., and Yeo et al. are applied as above for claims 1-3 and 5-11. Timmins et al., Timmins2, Boehm et al., Wojda et al., and Yeo et al. do not teach agitation at 200-800 rpm (claim 4). Bayley et al. teach that agitation is a result effective variable with respect to enucleation, with agitation at 450 rpm resulting in increased enucleation (see Abstract; p. e371, Fig. 1; p. e372, column 1; paragraph bridging p. e372 and e373). Based on these teachings, one of skill in the art would have found obvious to modify the method taught by Timmins1, Timmins2, Boehm et al., Wojda et al., and Yeo et al. by using agitation at 450 rpm with the reasonable expectation that doing so would in increase the yield of RBCs.
Thus, the claimed invention was prima facie obvious at the time of its effective filing date.
16. No claim is allowed. No claim is free of prior art.
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/ILEANA POPA/Primary Examiner, Art Unit 1633