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 .
Remarks
The amendments and remarks filed on 03/03/2026 have been entered and considered. The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior office action. The rejections and/or objections presented herein are the only rejections and/or objections currently outstanding. Any previously presented objections or rejections that are not presented in this Office Action are withdrawn. Claims 21-37 are pending; Claims 1-20 are cancelled; Claims 21-37 are amended; and Claims 21-37 are under examination.
Withdrawal of Objections
The objection to Claims 21, 26, 29, 31, 35, and 37 in the previous office action is withdrawn due to the amendment of the claims filed on 03/03/2026.
Withdrawal of Rejections
The rejection of Claim 24 under 35 U.S.C. 112(a), as failing to comply with the written description requirement, is withdrawn due to the amendment of the claim filed on 03/03/2026.
Priority
This application, U.S. Application number 17/058960, is a national stage entry of International Application Number PCT/IN2019/050404, filed on 05/21/2019, which claims foreign priority under 35 U.S.C. 119(a)-(d) to INDIA IN201821007692 filed on 06/01/2018.
It is noted that Applicant has not complied with one or more conditions for receiving the benefit of an earlier filing date of IN201821007692 under 35 U.S.C. 119(a)-(d) as follows: The later-filed application must be an application for a patent for an invention which is also disclosed in the parent application (e.g. a prior-filed foreign application). The disclosure of the invention in the parent application and in the later-filed application must be sufficient to comply with the requirements of 35 U.S.C. 112(a) or the first paragraph of pre-AIA 35 U.S.C. 112, except for the best mode requirement. See Transco Products, Inc. v. Performance Contracting, Inc., 38 F.3d 551, 32 USPQ2d 1077 (Fed. Cir. 1994). However, the disclosure of the prior-filed foreign application, IN201821007692, fails to provide adequate support or enablement in the manner provided by 35 U.S.C. 112(a) or pre-AIA 35 U.S.C. 112, first paragraph for one or more claims of this application. Specifically, the limitation of a cell specific perfusion rate (CSPR) is in the range of 5 pL per Cell per Day to 35 pL per Cell per Day during the entire production process, at last 3 lines of the newly submitted claim 21, was provided in PCT/IN2019/050404, filed on 05/21/2019, but is not supported by the prior-filed Application IN201821007692.
Claim Objections
Claim 22 is objected to due to the recitation of “the culture medium is selected from IMDM … CHO-S-SFM culture medium, Dulbecco's Modified Eagle medium …”, It is noted that the recited Markush group does not contain any connection word. A connection word “and” should be placed between CHO-S-SFM culture medium and Dulbecco's Modified Eagle medium in the Markush group. Appropriate correction is required.
Claim Rejections - 35 USC § 112, First Paragraph
Claim 25 is rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for pre-AIA the inventor(s), at the time the application was filed, had possession of the claimed invention. This is a new matter rejection.
Claim 25 is directed to the process of the base claim 21; and the claim 25 further recites the additional limitations to define the carriers as “cellulose-based carriers”, “dextran based microcarriers”, “porous cellulose microcarriers”, and/or “non-woven polymeric fiber disks”. Support for these specific carriers is not found in the disclosure of the specification of the originally filed application. In the 03/03/2026 response, Applicant failed to point to any disclosure of the specification for a written description of these limitations about the carriers. Therefore, the claim 25 with the additional limitations is directed to new matter.
Claim Rejections - 35 USC § 112(b), or 112, Second Paragraph
Claims 21-37 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor, or for pre-AIA the applicant regards as the invention.
Claim 21 is indefinite due to the recitation of “ optimizing perfusion rate from 0.3 VVD to 9 VVD, dissolved oxygen level from 2 % to 80%, agitation speed from 150 rpm to 180 rpm, temperature from 30°C to 40°C and pH from 6 to 8” in the step iii). It is unclear whether the step iii) requires optimizing a perfusion rate having a value of 0.3 VVD to a perfusion rate having a value of 9 VVD, or optimizing a perfusion rate to a value in the range between 0.3 VVD and 9 VVD. According to the disclosure of the specification, the “optimizing perfusion rate from 0.3 VVD to 9 VVD” is interpreted as “optimizing a perfusion rate to a value from 0.3 VVD to 9 VVD for being used in the culturing step i)”. The ranges for dissolved oxygen level, agitation speed, temperature, and pH recited in the step iii) have the same issue as the range for perfusion rate; and they will be interpreted in the same way as that of perfusion rate according to the disclosure of the specification. In addition, the claim is indefinite due to the recitation of “monitoring residual glucose from 0.2gL-1 to 2 gL-1” in the step v). It is noted that the step v) does not define any specific level of the residual glucose to be maintained in the culturing step. It is unclear whether the recited phrase refers to monitoring residual glucose when its value falls into a range from 0.2gL-1 to 2 gL-1, or refers to monitoring a residual glucose and maintaining its value in a range from 0.2gL-1 to 2 gL-1 in the culturing step. Furthermore, the claim recites the limitation of “the process step (i) to (vi) maintains a cell density of greater than 140 x 106 cells/mL is maintained in the culturing step of the production process”. The steps (i) to (vi) and the culturing step in this limitation conflict with each other. It is unclear whether the limitation requires a cell density of greater than 140x 106 cells/mL to be maintained in all the process steps (i) to (v), or only in a single culturing step. For the purpose of examination, the recited phrase is interpreted as “a cell density of greater than 140x 106 cells/mL is maintained in the culturing step of the production process”, based on the disclosure of the specification. Finally, the claim recites the limitation “the cell specific perfusion rate”. There is no antecedence basis for this limitation (Note: the steps i) – vi) do not define any cell specific perfusion rate).
Claim 22 is indefinite due to the recitations of “preferably recombinant TNK-tPA producing CHO-DG44 cell line” and “preferably IMDM and CHO-S-SFM”. The recited “preferably” renders the claim indefinite because it is unclear whether the cell line or culture media following the term “preferably” are part of the claimed invention. See MPEP § 2173.05(d). In addition, the formulation or components of the “CHO-S-SFM” medium recited in the claim is not disclosed or taught in the specification, prior art, or any public resource (Note: only “CHO-S-SFM II” is taught/disclosed). It is unclear what specific components are comprised in the “CHO-S-SFM” medium.
Claim 23 recites the limitation “pooling” at the end of the claim, but does not define a subject material to be pooled. It is unclear what specific material is subjected to the pooling.
Claim 24 is indefinite due to the recitation of “the pressure inside the bioreactor”. There are multiple pressures in the bioreactor, such as a headspace gas pressure, liquid phase pressure, and pressures in perfusion device inside the bioreactor. It is unclear which specific pressure the recited “the pressure” refers to.
Claim 25 is indefinite due to the recitation of “selected from the group consisting of … non-woven polymeric fiber disks, or combinations thereof”. Given the recited Markush group has an alternative connection term “or”, it is not clear what specific members the Markush group consists of. For the purpose of examination, the phrase is interpreted as “selected from the group consisting of … non-woven polymeric fiber disks, and combinations thereof”. The claim also recites the limitation “preferably non-woven polyester fibrous disks and polyester microfibrous carriers, as packing material”. The term “preferably” renders the claim indefinite because it is unclear whether the specific packing material following the term “preferably” is part of the claimed invention. See MPEP § 2173.05(d). Furthermore, the claim recites the limitations “microcarriers” and “microfibrous carriers”. It is noted that the term “micro” is a relative term, standing for “small”. The specification does not define these terms with regard to which specific size range is considered as being microcarriers or microfibrous carriers. In the absence of a benchmark, it is unclear which carriers can be considered as microcarriers or microfibrous carriers. For the purpose of examination, the limitations are interpreted as “carriers” or “fibrous carriers”.
Claim 26 is indefinite due to the recitations of “preferably 2.5 VVD”, “preferably 50% to 70%” and “preferably 160 rpm to 170 rpm”. The term “preferably” renders the claim indefinite because it is unclear whether the limitations following the recited “preferably” are part of the claimed invention. See MPEP § 2173.05(d).
Claim 28 recites the limitation “preferably 1.5 to 4.5”. The term “preferably” renders the claim indefinite because it is unclear whether the limitations following this term are part of the claimed invention. See MPEP § 2173.05(d).
Claim 29 is indefinite due to the recitation of “the capacitance”. There is no sufficient antecedence basis for this term in the claim. For the purpose of examination, the term is interpreted as “a capacitance of cell culture” in the bioreactor. Furthermore, the claim is indefinite due to the recitation of “glucose level is from 0.20.1 g/L to 2 g/L”. It is unclear whether the “0.20.1 g/L” is referred to a range from 0.2 g/L, or to 0.1 g/L. For the purpose of examination, the phrase is interpreted as “the residual glucose level is from 0.2 g/L to 2 g/L” to be consistent with the base claim 21.
The remaining claims are rejected for depending from an indefinite claim.
Claim Rejections - 35 USC § 103
Claims 21-23, 26, 29, 31-34, and 36-37 are rejected under 35 U.S.C. 103 as being unpatentable over Mishra et al. (WO 2012/085933, 2012, cited in IDS) in view of Wang et al. (US patent No. 11702628, 2023, effective filing date: Mar. 31, 2017, of record) and Goudar et al. (US 20210163592, 2021, effective filing date: Dec. 11, 2017, of record).
Wang et al./US patent No. 11702628 is equivalent to Wang et al./WO/2018/178069, published on Oct 4, 2018. Accordingly, the claims are also rejected under 103 over Mishra et al. in view of Wang et al. (WO/2018/178069) and Goudar et al. All citations are made to US patent No. 11702628.
Mishra et al. teach a process for production of a pharmaceutical-grade recombinant TNK, known as Tenecteplase (a synonym of the “TNK-tPA” recited in the instant claim 1, as evidenced by the disclosure of the specification, see page 2/para 5/line 1), through a continuous perfusion fermentation system, comprising steps: (i) providing a bioreactor having a continuous perfusion system; (ii) culturing TNK-tPA-producing recombinant mammalian cells in a IMDM culture medium in the perfusion bioreactor and then replacing the IMDM culture medium with a CHO-S-SFM II culture medium without FBS, wherein the mammalian cells were genetically engineered cells from Chinese Hamster Ovary (CHO) cell line; (iii) perfusing and harvesting a culture broth from the perfusion bioreactor, wherein the perfusion bioreactor contains cell-supporting media (i.e. carriers) in the core of the bioreactor to provide attachment for the mammalian cells in the perfusion bioreactor (Note: the perfusion bioreactor bed-packed with cell-supporting carriers reads on the “packed-bed perfusion system” in claim 1); maintaining the culturing with optimized parameters of perfusion rate, dissolved oxygen (DO) level, agitation speed, temperature, and pH, such that the perfusion is run at a rate to allow effective collection of harvested broth, wherein a dissolved oxygen (DO) level is at 30% (reading on the claimed 20%-80%), agitation speed at 100 rpm, a temperature 36.6oC (reding on the claimed 30-40oC), and a pH 7.2-7.4 (reading on the claimed 6-8) (Note: these comprise designing bioreactor system and optimizing parameters such as perfusion rate, DO level, agitation speed, temperature, and pH); managing cell growth and viability by performing periodic microscopic and biochemical tests to detect and monitor health and integrity of growing cells; and extracting and purifying the recombinant TNK-tPA from the collected culture broth (abstract, Claims 1-4, Examples 2-4, page 1/first para, and the para spanning pages 7 and 8). Given Mishra et al. expressively teach ensuring a health cell culture by managing cell growth/viability and periodic biochemical tests of cell culture, the method of Mishra et al. inherently comprises controlling a level of toxic-by-products and maintaining toxic-by-products in cell culture at a desirable level for ascertaining health cell growth during the culturing step. Regarding the step v) recited in the claim 21, Mishra et al. further teach maintaining glucose between 0.3-1.5 g/L for supporting cell growth (page 8, para 1, line 5 from bottom), thus meeting the claimed limitation of managing cell growth and viability by monitoring residual glucose from 0.2 g/L to 2 g/L.
The method of Mishra et al. differs in part from the method of the claim 21 in that Mishra et al. are silent about whether a cell density is greater than 140 x 106 cell mL-1 and a cell specific perfusion rate/CSPR is in a range of 3-35 pL/Cell/Day. However, Mishra et al. teach culturing recombinant CHO cells for a large-scale of TNK-tPA production, and that TNK-tPA products as a pharmaceutical agent are safe and effective in treating stroke (abstract).
Goudar et al. teach a process for producing recombinant proteins heterologously expressed in mammalian cells (e.g. recombinant cells of a CHO cell line) in a perfusion bioreactor comprising polyethersulfone carrier for cell attachment and filter, comprising a step of culturing the cells by perfusion, the perfusion culture is more preferably run for at least 35 days (abstract, claims 1, 9, and 24, paras 0442/line 2, 0443, 0461, 0471). Goudar et al. further teach applying a cell-specific perfusion rate (CSPR) in a range of 0.01 to 0.15 nL/cell/day (i.e. 10 to 150 pL/cell/day) or preferably in a range of 0.015 to 0.0315 nL/cell/day (i.e. 15 to 31.5 pL/cell/day) for carrying out the perfusion culture (Claim 9) (Note: these ranges either read on or overlaps with the claimed range of 5 to 35 pL/cell/day, thus meeting or rendering the claimed ranges obvious). Goudar et al. further teach that a minimum CSPR is a rate that delivers minimum nutrients and supports high productivity of cell cultures, and that application of the minimum CSPR or a CSPR close to the minimum CSPR is of particular practical importance for culturing cells at high cell densities, for example in high cell density cultures (HCDC), and for example a HCDC is directed to a cell culture having a viable cell density (VCD) at least 85 x106 cells/mL, or at least 100 x106 cells/mL (page 6/right col./para. 1); and Goudar et al. continue to teach that a typical minimum CSPR is 0.01 nL/cell/day (i.e. 10 pL/cell/day) (page 6, para 0087/lines 1-2).
Wang et al. teach a process for producing recombinant proteins heterologously expressed in mammalian cells in a perfusion bioreactors comprising fibers/carriers of polyethersulfone (PES) for cell attachment, comprising: culturing the mammalian cells (e.g. cells of a CHO-DG44 cell line) by perfusion of a perfusion culture medium (column 3/line 51 - column 4/line17, col. 4/lines 61-62, col. 5/lines 54-56, col. 19/lines 20-35, col. 22/lines 1-8, Example 1/col. 25/lines 16-18 and 22-23). Wang et al. also teach that the CSPR equals a perfusion rate per cell density and based on a desired CSPR the perfusion rate is increased as a linear function of the cell density; and that an ideal CSPR depends on cell lines and cell medium and the ideal CSPR should result in optimal growth rate and productivity (column 7/lines 55-67, column 8/lines 1-5). Wang et al. suggest a reasonable starting CSPR range of 50 -100 pL/cell/day and adjusting for finding optimal rate for a specific cell line and specific cell medium (column 7/last line, column 8/lines 1-5), and Wang et al. further teach a specific CSPR in the range from 0.03 to 0.08 nL/cell/day (i.e. 30 - 80 pL/cell/day) to be maintained the same for the culturing process (Example 3, col 27, lines 33-37) (Note: the range of 30 - 80 pL/cell/day overlaps with the claimed range of 5-35 pL per cell per day, thus rendering the claimed range obvious).
It would have been obvious to modify the method of Mishra et al. by culturing/maintaining TNK-tPA-producing mammalian cells at a high cell density of greater than 140 x 106 cell mL-1 and also maintaining a CSPR in 5-35 pL per cell per day during the entire production process for increasing productivity of TNK-tPA, as taught by Goudar et al and Wang et al. One of ordinary skill in the art would have been motivated to do so, because there is a need of producing more TNK-tPA in view of that Mishra et al. teach TNK-tPA is a safe and effective pharmaceutical agent and recombinant CHO cells need to be cultured for a large-scale of TNK-tPA production. Furthermore, it is well known in the art that maintaining the CSPR at a minimum level, typically 10 pL per cell per day (reading on the claimed ranges), in a cell culture having a high cell density of at least 100 x 106 cell mL-1 (encompassing the claimed 140 x 106 cell mL-1) in the entire production process is particularly important for supporting high productivity of heterologously expressed proteins in the mammalian cells (recombinant CHO cells), as supported by Goudar et al.; and that CSPR is interconnected to cell density/growth in the bioreactor and maintaining CSPR at a specific range facilitates optimal productivity and growth of cells, as supported by Wang et al. Moreover, a CSPR in the claimed range 5-35 pL/cell/day has been successfully used in the art for performing perfusion culture and producing heterologous proteins in the mammalian cells, as supported by Goudar et al. and Wang et al. One of ordinary skill in the art has a reasonable expectation of success at modifying the method of Mishra et al., because both the method of Mishra et al. and the methods of Goudar et al. and Wang et al. are directed to producing heterologous proteins from recombinant mammalian cells through perfusion culture in perfusion reactors and the teachings of the prior art are readily applicable to the method of Mishra et al.
Regarding the limitation about the range of a perfusion rate in the claim 21,
Mishra et al. are silent about perfusion rate of culture medium/broth in their method. However, it would have been obvious to maintain a perfusion rate in the range of 0.3 – 9 VVD in the method suggested by Mishra et al., Wang et al. and Goudar et al. for producing TNK-tPA, because it is a common practice in the art to control perfusion rates for facilitating perfusion-based culture process and the claimed ranges for perfusion rate are well known in the art. In support, Goudar et al. further teach that the perfusion rate of the culturing process is in a range of 0.5 to 2 VVD, or 1 to 7 VVD, or 2 to 6.4 VVD (paras 0461 and 0471, claims 7 and 8), which reads the claimed range, thus meeting the claimed limitation. Further in support, Wang et al. teach that the perfusion rate is the volume to be added and removed and is typically measured per day, and it may be controlled through cell density, pH, O2 consumption and metabolites of culture medium (column 7/lines 48-53, column 18/lines 62-67); and that the perfusion rate of the culturing process typically starts from 0.5 VVD and goes up to about 5 VVD, or in a range of 0.5 – 2 VVD (col. 7/lines 58-61) (Note: these ranges read on the claimed VVD range, thus meeting the claimed limitation).
Regarding the limitation about the range of agitation rate in the claim 21, the agitation rate of 100 rpm taught by Mishra et al. does not exactly match the claimed range. However, it is considered that the speed of Mishra et al. can be readily modified by routine optimization based on specific factors such as bioreactor’s working volume, cell density, contents of medium, and a rate of aeration. It is well settled that routine optimization is not patentable, even though it results in significant improvement over the prior art (see MPEP 2144.05).
Regarding the limitation of real time capacitance feedback in the claim 21, Mishra et al. do not teach managing cell growth/viability through real time capacitance feedback. However, it would have been obvious to manage cell growth/viability through real time capacitance feedback in the method suggested by Mishra et al., Wang et al. and Goudar et al. for controlling cell growth and maintaining cell density at a desirable level, because the capacitance feedback is a well-established technique in the art for managing and controlling cell growth/viability, and it is well known in the art that a cell density in culture medium is measured and adjusted through real time capacitance measurement and feedback because there is a direct correlation between the capacitance and cell density; and a cell density can be controlled at a desirable range through real time capacitance feedback and maintaining the capacitance at a specific target range. In support, Goudar et al. further teach a step of measuring capacitance for controlling cell growth and cell density in perfusion cell culture, and specifically indicate that a real time capacitance feedback at a value of 70 or 80 pF/cm, as provided by a real time capacitance probe, represents a cell density of 60 - 80 x 106 cells/mL in the cell culture (paras 0443/lines 1-5, 0461/lines 1-5, 0471/lines 1-5). Further in support, Wang et al. further teach that on-line (real time) capacitance probes are cell density probes known to the person skilled in the art, and these capacitance probes are used to control and manage viable cell density, i.e. cell growth/viability, at a desirable level during perfusion culturing process through removing excess cells from bioreactor (i.e. cell bleed) based on real time capacitance feedback from the probes (col. 19/lines 1-9; Example 3/col 27/lines 37-40).
Regarding the claims 22 and 32, Mishra et al. teach IMDM culture medium and CHO-S-SFM II culture medium. In addition, Mishra et al. teach the TNK-tPA-producing mammalian cells are recombinant mammalian cells of a CHO cell line, whose scope encompasses CHO-DG44 cell line. It would have been obvious to use a CHO-DG44 cell line as the CHO cell line in the method suggested by Mishra et al., Wang et al. and Goudar et al. for preparing recombinant TNK-tPA-producing mammalian cells and heterologously producing TNK-tPA, because CHO-DG44 cell line is commonly used in the prior art for producing heterologous proteins/enzymes, as supported by Wang et al., who further teach that CHO-DG44 cells are mammalian cells preferably for expressing heterologous proteins (Col. 4/lines 62-62, col. 12/lines 31-32, col. 27/lines 40-41, Claim 5).
Regarding the claim 31, Mishra et al. further teach purifying TNK-tPA in a process involved with gel filtration chromatography (i.e. size exclusion chromatography) (page 5/para 2, page 8/last para; and page 9/para 1); and that purity of TNK-tPA was determined by SDS-Page electrophoresis and HPSEC (high performance size exclusion chromatography, reading the claimed limitation “size exclusion chromatography”) (page 5/first half of para 2, Table A, Example 5), wherein the purity of TNK-tPA is more than 95% (page 9/para 1/line 5 from bottom) or more than 99%, as determined by HPSEC (page 6, para 4; Figure 3), thus meeting the claimed limitation about TNK-tPA purity. In addition, Goudar et al. teach the CSPR range of 15 to 31.5 pL/cell/day (as indicated above), which overlaps with the claimed 10-20 pL/cell/day, thus renders the claimed range to be obvious. See MPEP 2144.05. Regarding the specific productivity “from 1 to 5 pg per cell per Day” recited in the claim, Mishra et al. are silent about a specific productivity of TNK-tPA. However, it would have been obvious to apply a specific productivity of TNK-tPA in the range from 1 to 5 pg per cell per day in the method suggested by the cited prior art for producing TNK-tPA in a perfusion culture of mammalian cells of a CHO cell line (e.g. CHO-DG44 cell line), because it is well known in the art to apply a specific productivity in the claimed range for effectively producing heterologous proteins in mammalian cells from a CHO cell line, such as CHO-DG44 cell line. In support, Wang et al. further teach adjusting a level of specific productivity based on specific cell lines used for producing heterologous proteins and expressively teach using specific productivity in the range of < 20 pg/cell/day for the CHO-DG44 cells given CHO-DG44 cell line is a low producing cell line (Example 3, col 27, lines 40-43) (Note: the range of less than 20 pg/cell/day encompasses the claimed 1 to 5 pg/cell/day, thus rendering the claimed range obvious). Regarding the limitation “a period of “40 to 60 days” recited in the claim, Mishra et al. teach a period of 3-4 months for running the perfusion reactor (page 8/para 1/line 4 from bottom), which does not exactly match the claimed period. However, a time length for running a perfusion reactor and culturing mammalian cells expressing heterologous proteins is an obvious design choice and is readily adjustable based on specific culture conditions and cell lines used. Furthermore, it has been well known in the art to run a perfusion reactor and culture mammalian cells expressing heterologous proteins for a time period in the claimed range, as supported by Goudar et al., who teach a time period of at least 35 days (as indicated above), 40 days, or above 40 days (see Figs. 2, 10-11, 13).
Regarding the further limitation about osmolality in Claim 26, Mishra et al. are silent about an osmolarity level of medium in their method. However, it would have been obvious further to maintain an osmolarity level in the range of 290 - 350 mOsm/kg in the method suggested by Mishra et al. and other cited prior art for producing TNK-tPA, because it is a common practice in the art to control osmolarity levels for facilitating perfusion-based culture process and the claimed range for osmolarity is well known in the art, as supported by Wang et al., who further teach that the osmolarity level of the medium is preferably in the range of 300-500 mOsm/kg; (column 4/lines 56-58, Claims 7 and 10). It is noted that the osmolarity range of Wang et al. overlaps with the claimed osmolarity range, thus rendering the claimed range to be obvious.
Regarding the further limitation about the capacitance range 50 pF/cm – 250 pF/cm in Claim 29, Mishra et al. are silent about capacitance of cell culture. However, the method of Mishra et al. as modified by Wang and Goudar comprises steps of measuring capacitance of a cell culture and controlling/managing cell growth/viability through real time capacitance feedback for producing TNK-tPA, for the reasons indicated above. Goudar et al. teach using capacitances of 70 pF/cm and 80 pF/cm as set points for controlling viable cell density (paras 0443/lines 3-5, 0461/lines 3-5, 0501/lines 3-5) (Note: these capacitances read on the claimed range). In view of the cited prior art, it would have been obvious to further maintain the capacitance of perfusion cell culture in a range of 50 pF/cm – 250 pF/cm in the method suggested by Mishra et al., Goudar et al. and Wang et al. for producing TNK-tPA, because there is a direct correlation between capacitance and viable cell density, and maintaining capacitance at such a range can ascertain there are sufficient viable cells in the bioreactor for producing TNK-tPA, as supported by Goudar et al. and Wang et al.
Regarding Claim 33, Mishra et al. teach the temperature is kept at 33.5oC during the production phase (page 8, para 1/lines 6-7 from bottom), which reads on the claimed range, thus meeting the claimed limitation.
Regarding Claim 34, Mishra et al. teach the temperature is kept at 36.6oC before it is reduced to 33.5oC in the production phase (page 8, lines 8 and 12-13). It is noted that during the process of reducing the temperature, the temperature of the perfusion culture is first reduced to 36oC, then to 35oC before reaching the target temperature 33.5oC. As such, the temperature of Mishra et al. went through a range from 36oC to 35oC, thus meeting the claimed limitation. Furthermore, the temperature 36.6oC taught by Mishra et al. nearly touches the high end of the claimed range of 35oC-36oC, which renders the claimed range to be obvious, because the difference is virtually negligible absent any showing of unexpected results or criticality, and the prior art value is so close that the same effect would have been reasonably expected. See MPEP 2144.05(I), which states “a prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close”.
Regarding Claim 36, Goudar et al. teach the prefusion rate is in a range from 1 to 7 VVD or from 2 to 6.4 VVD, and Wang et al. teach the prefusion rate is in a range of 0.5 to 5 VVD, as indicated above. These ranges encompass the claimed 3 VVD and 2.5 VVD, thus rendering the claim to be obvious. See MPEP 2144.05.
Regarding Claim 37, the glucose range of 0.3-1.5 g/L taught by Mishra et al. overlaps with the claimed range 0.1 g/L – 0.4 g/L, thus rendering the claim to be obvious. See MPEP 2144.05.
Regarding Claim 23, Mishra et al. teach creating a cell bank of recombinant cell line with good TNK productivity, and preparing a working bank/ recombinant cell line to be used in large scale perfusion fermentation process (page 7/Example 2/lines 3-5 from bottom). Mishra et al. further teach starting an initial culture of recombinant cells in IMDM medium, for large-scale of TNK protein production by employing a perfusion bioreactor; and then amplifying a culture of about 1x106 cells to about 6-12 x 109 cells through a serial sub-culturing/amplification processes in tissue culture flasks and roller bottles, wherein the confluence of the cells was maintained at more than 90% of the growing surface area in the flasks and roller bottles before harvesting cells for next step; and then the 6-12 x 109 cells were removed from the flasks and roller bottles (by pooling cells together) and transferred to the bioreactor having a volume of 5 Liters (page 7/last para and page 8/lines 1-6), which gives a cell density of about 1.2 – 2.4 x 109 cells/L. The 1.2 x109 cells/L in the range of Mishra et al. nearly reads on the high end of the claimed range of 900 – 1100 x 106 cells/L (i.e. 0.9 – 1.1 x109 cells/L), thus rendering the claimed range to be obvious, because such a difference between the claimed cell density and that of Mishra et al. is virtually negligible absent any showing of unexpected results or criticality, and the prior art value is so close that the same effect would have been reasonably expected. See MPEP 2144.05(I), which states “a prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close”. Regarding the limitations about a cell density of 8-12 x106 cells mL-1 and surface areas of containers recited in the claim, Mishra et al. teach obtaining about 1x106 cells from an initial culture and using flasks and roller bottles as containers for further subculturing and amplifying cells, but Mishra et al. are silent about a specific cell density of the initial culture and specific surface areas of the containers. However, it is an obvious design choice to culture cells to obtain an initial culture at cell density of 8-12 x106 cells mL-1 in the method suggested by Mishra et al., because the amount of about 1x106 cells taught by Mishra et al. can be readily obtained from an initial cell culture at this cell density, by simply adjusting a volume of the culture to be harvested. For example, taking 0.1 ml from a culture having a cell density of 10 x106 cells/mL (in the claimed range) will give an amount of 1x106 cells. Furthermore, Mishra et al. teach a serial sub-culturing/amplification processes in tissue culture flasks and roller bottles for a large-scale of TNK-tPA production, and more than 90% of the growing surface area in the tissue culture flasks and roller bottles has the confluence of the cells. A surface area of a flask or roller bottle can be readily obtained because all commercially available flasks and bottles have defined dimensions. It is an obvious design choice and routine optimization to use a specific total surface area of a certain number of flasks and roller bottles for conducting the sub-culturing/amplification, so as to provide sufficient surface area such as 2 x 850 cm2, 4 x 1700 cm2 or 4 x 1700 cm2 for obtaining sufficient cultured cells, thus allowing about 900 -1100 x 106 cells/L can be pooled and ascertaining cells to be cultured cells to a cell density of >140 x 1x106 cells mL-1 in the culturing step of the method of Mishra et al. as modified by Goudar et al. and Wang et al.
Therefore, the invention as a whole would have been prima facie obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention.
Claims 21-23, 25-26, 29, 31-34, and 36-37 are rejected under 35 U.S.C. 103 as being unpatentable over Mishra et al. (WO 2012/085933, 2012, cited in IDS) in view of Wang et al. (US patent No. 11702628, 2023, effective filing date: Mar. 31, 2017, of record) and Goudar et al. (US 20210163592, 2021, effective filing date: Dec. 11, 2017, of record), as applied to Claims 21-23, 26, 29, 31-34, and 36-37, further in view of Kaufman et al. (Cytotechnology, 2000, 33: 3–11, of record).
Wang et al./US patent No. 11702628 is equivalent to Wang et al./WO/2018/178069, published on Oct 4, 2018. Accordingly, the claims are also rejected under 103 over Mishra et al. in view of Wang et al. (WO/2018/178069), Goudar et al., further in view of Kaufman et al. All citations are made to US patent No. 11702628.
The teachings of Mishra et al. as Modified by Goudar et al. and Wang et al. are described above.
Regarding Claim 25, Mishra et al. teach that the bioreactor is bed-packed with cell-supporting matrix, i.e. carrier (page 8, para 1). Mishra et al. do not teach the bioreactor comprises a packed-bed basket impeller.
It would have been obvious to culture the recombinant mammalian cells in a perfusion bioreactor comprising a packed-bed basket impeller in the modified method of Mishra et al. for continuously operating the perfusion bioreactor for producing TNK-tPA, because it is known in the prior art that a perfusion bioreactor equipped with a packed-bed basket impeller is well suited for continuous perfusion operation of mammalian cells for production of heterologous proteins. In support, Kaufman et al. teach a method for continuous production of heterologous proteins from recombinant mammalian cells, comprising a step of culturing the cells in a packed-bed perfusion bioreactor comprising a packed-bed basket impeller, wherein the cells are immobilized in the packed bed (title, abstract, and page 4/col 2/last para). Kaufman et al. further teach that the continuous perfusion operation of the bioreactor having packed-bed basket impeller is preferably chosen for production of heterologous proteins (abstract, last 2 lines).
It is noted that Kaufman et al. further teach that the packed-bed basket contains
60 g of Fibra-CelTM disks (as carriers for cell attachment) made of polyester non-woven fabric (page 4, col 2, last para). These teachings render the limitation about polyester microfibers in the claim 5 to be obvious.
Therefore, the invention as a whole would have been prima facie obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention.
Claims 21-23, 26, 29-34, and 36-37 are rejected under 35 U.S.C. 103 as being unpatentable over Mishra et al. (WO 2012/085933, 2012, cited in IDS) in view of Wang et al. (US patent No. 11702628, 2023, effective filing date: Mar. 31, 2017, of record) and Goudar et al. (US 20210163592, 2021, effective filing date: Dec. 11, 2017), as applied to Claims 21-23, 26, 29, 31-34, and 36-37, further in view of Zhou et al. (US 20150158907, 2015, of record).
Wang et al./US patent No. 11702628 is equivalent to Wang et al./WO/2018/178069, published on Oct 4, 2018. Accordingly, claims are also rejected under 103 over Mishra et al. in view of Wang et al. (WO/2018/178069), Goudar et al. and Zhou et al. All citations are made to US patent No. 11702628.
The teachings of Mishra et al. as Modified by Goudar et al. and Wang et al. are described above.
Regarding Claim 30, Mishra et al. further teach that the recombinant TNK-tPA is a protein secreted from mammalian cells into the medium, and it is extracted from the culture by filtering harvested broth through filters (Note: this is a continuous two-phase filtration process, i.e. a liquid medium phase and a biomass solid phase in the broth), and filtrates are collected for further purification (Example 2: page 7/para 2/lines 1-4; Example 3: page 8/para 1/last 3 lines; page 3/para 2/line 4).
Mishra et al. do not teach conducting the filtration with a housing-membrane-type filter comprising a polyethersufone (PES) cartridge filter. However, It would have been obvious to extract the recombinant TNK-tPA through a two phase continuous filtration process by using a housing-membrane-type filter comprising a polyethersufone (PES) cartridge filter with pore sizes of 0.2 um and/or 0.5 uM in the modified method of Mishra et al. for producing TNK-tPA. This is because it is well known in the prior art that a housing-membrane-type filter comprising a PES cartridge filter of 0.2 and/or 0.5 uM can be used for effectively conducing the filtration and extracting secreted recombinant proteins from mammalian cells. In support, Zhou et al. teach methods of continuously processing a cell culture in a perfusion bioreactor for producing recombinant proteins, comprising steps: culturing mammalian cells that produce heterologous proteins in the perfusion bioreactor having a tangential flow filtration (TFF unit) in an open circular filtration system; continuously flowing the cell culture through the TFF unit for perfusion, wherein the TFF unit has a first and a second inlet, and comprises two or more cartridge filters; and wherein a filtrate obtained from the TFF unit can be passed into two or more chromatographic membranes in a multicolumn chromatography system (MCCS) for extracting and purifying secreted recombinant proteins (claims 1, 2, 7, and 16-19, paras 0002, 0005-6, and 0099, Example 1/pages 21-22, Fig. 1), wherein the cartridge filter(s) have an average pore size of between about 0.1 um to about 0.45 .um, or of about 0.20 .um, a filter composed of polyethersulfone (PES) (paras 0086-87, 0152); and wherein the culturing of mammalian cells lasts for 60 days (Figs. 11-21).
It is noted that Zhou et al. teach the capacitance of the cell culture largely in the range of 50 pF/cm – 250 pF/cm over a period of 60 days (Fig. 12), with cell viability maintained at a level of at least 70% (Figs. 11-12, para 0155), and that there is a direct correlation between the capacitance and cell density (Table 3), which further render the limitations in claim 29 to be obvious.
Therefore, the invention as a whole would have been prima facie obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention.
Claims 21-23, 26-27, 29, and 31-37 are rejected under 35 U.S.C. 103 as being unpatentable over Mishra et al. (WO 2012/085933, 2012, cited in IDS) in view of Wang et al. (US patent No. 11702628, 2023, effective filing date: Mar. 31, 2017, of record) and Goudar et al. (US 20210163592, 2021, effective filing date: Dec. 11, 2017, of record), as applied to Claims 21-23, 26, 29, 31-34, and 36-37, further in view of Clincke et al. (American Institute of Chemical Engineers, 2013, Vol. 29(3): 754-767, cited in IDS).
Wang et al./US patent No. 11702628 is equivalent to Wang et al./WO/2018/178069, published on Oct 4, 2018. Accordingly, claims are also rejected under 103 over Mishra et al. in view of Wang et al. (WO/2018/178069), Goudar et al. and Clincke et al. All citations are made to US patent No. 11702628.
The teachings of Mishra et al. as Modified by Goudar et al. and Wang et al. are described above.
Regarding Claim 27, it is noted that the time range of “40 to 60 days” recited in the claim would have been obvious over cited prior art for the reasons indicted above. Regarding the levels of ammonia and lactate recited in the claim, Mishra et al. teach the glucose concentration, but not that of ammonia or lactate. However, it would have been obvious to measure and control concentrations of ammonia and lactate at the levels of less than 100 mM and less than 3g/L, respectively, in the modified method of Mishra et al. for ascertaining a healthy cell culture for TNK-tPA production, because ammonia and lactate are major toxic by-products in fermentation process of mammalian cells, and these levels are well known in the art for a normal healthy cell culture in the fermentation process. In support, Wang et al. further teach ammonia and lactate are metabolic by-products and their accumulation has adverse effect and reduces cell viability (col. 9/lines 4-6). Further in support, Clincke et al. teach a high cell density perfusion-based fermentation process for producing heterologous proteins in recombinant CHO mammalian cells (title, abstract), and providing proper perfusion to prevent toxic by-product accumulation in cultures (page 757/left col/lines 1-3). Clincke et al. further demonstrate that the formation of ammonia and lactate during a period of 50 days of fermentation process for culturing the mammalian cells (Figs. 5e and 5f, results in page 760). Regarding the specific ranges of ammonia and lactate recited in the claim, it appears that these ranges only reflect the levels of ammonia and lactate in a normal healthy cell culture, and there is no showing of novelty in the claim, as supported by Figs. 5e and 5f of Clincke et al., where the measured levels of ammonia and lactate (e.g. TFF#10) either fall into or nearly touch the claimed ranges <100 mM and <3g/L (Note: 3g/L recited in the claim is equivalent to 33.3 mM), thus meeting the claimed ranges or render the claimed ranges obvious.
Regarding the claim 35, the levels of ammonia and lactate of Clincke et al. do not exactly match the claimed levels over the entire period of 50 days. However, it is considered that the concentration levels of Clincke et al. can be readily modified by routine optimization for reducing the toxic byproduct and at the same time promoting a healthy cell population for TNK-tPA production. Furthermore, it is well settled that routine optimization is not patentable, even though it results in significant improvement over the prior art (see MPEP 2144.05).
Therefore, the invention as a whole would have been prima facie obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention.
Claims 21-23, 26-29, and 31-37 are rejected under 35 U.S.C. 103 as being unpatentable over Mishra et al. (WO 2012/085933, 2012, cited in IDS) in view of Wang et al. (US patent No. 11702628, 2023, effective filing date: Mar. 31, 2017, of record), Goudar et al. (US 20210163592, 2021, effective filing date: Dec. 11, 2017, of record), and Clincke et al. (American Institute of Chemical Engineers, 2013, Vol. 29(3): 754-767, cited in IDS), as applied to Claims 21-23, 26-27, 29, and 31-37, further in view of Collins et al. (US 2013/0231255, 2013, of record).
Wang et al./US patent No. 11702628 is equivalent to Wang et al./WO/2018/178069, published on Oct 4, 2018. Accordingly, claims are also rejected under 103 over Mishra et al. in view of Wang et al. (WO/2018/178069), Goudar et al., Clincke et al., and Collins et al. All citations are made to US patent No. 11702628.
The teachings of Mishra et al. as Modified by Goudar et al., Wang et al. and Clincke et al. are described above.
Regarding Claim 28, Clincke et al. further demonstrate the glucose concentration levels over the period of 50 days of fermentation process (see Fig. 5c), and teach that the lactate is a byproduct of glucose consumption by cultured cells (page 756, left col., para 2/lines 1-2). By comparison of Figs. 5c and 5e of Clincke et al., it appears that not all of the ratios of Lactate/glucose over the period of 50 days fall into the claimed range. However, it is considered that the concentration levels of lactate and glucose taught by Clincke et al., can be readily modified by routine optimization for arriving at a desirable ratio of lactate/glucose for reducing the toxic byproduct lactate and at the same time providing sufficient glucose nutrient for maintaining a healthy cell population for TNK-tPA production. It is well settled that routine optimization is not patentable, even though it results in significant improvement over the prior art (see MPEP 2144.05). Furthermore, the claimed range for ratios of Lactate/glucose would have been obvious to one of ordinary skill in the art, because it is known in the prior art that a ratio of Lactate/glucose in the claimed range can be used for controlling a process of producing heterologous proteins from recombinant mammalian cells, as supported by Collins et al. In details, Collins et al. teach a method for producing recombinant glycoprotein from mammalian cells in a fermentation process comprising a perfusion culture system, comprising a step of culturing the mammalian cells for heterologously expressing the proteins, wherein the mammalian cells are from CHO cells, specifically CHO DG44 cell line (Claim 56, paras 0079/lines 5-6, 0101/lines 1 and 5-7), wherein the culturing process produces byproducts including ammonia and lactate (page 5/left col/lines 2-4 from bottom); and wherein the a ratio of Lactate/glucose is set up at a level less than 2, 1 or 0.5 for controlling the fermentation process (paras 0078/lines 2-4 from bottom, 0079/lines 2-4 from bottom). It is noted that the ratios of less than 2, 1 and 0.5 taught by Collins et al. overlap with the claimed range “2:5 to 8:5”, thus rendering the claimed range to be obvious.
Therefore, the invention as a whole would have been prima facie obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention.
Claims 21-24, 26, 29, 31-34, and 36-37 are rejected under 35 U.S.C. 103 as being unpatentable over Mishra et al. (WO 2012/085933, 2012, cited in IDS) in view of Wang et al. (US patent No. 11702628, 2023, effective filing date: Mar. 31, 2017, of record) and Goudar et al. (US 20210163592, 2021, effective filing date: Dec. 11, 2017, of record), as applied to Claims 21-23, 26, 29, 31-34, and 36-37, further in view of Dehottay et al. (US 2015/0166948, 2015, of record).
Wang et al./US patent No. 11702628 is equivalent to Wang et al./WO/2018/178069, published on Oct 4, 2018. Accordingly, the claims are also rejected under 103 over Mishra et al. in view of Wang et al. (WO/2018/178069), Goudar et al., further in view of Dehottay et al. All citations are made to US patent No. 11702628.
The teachings of Mishra et al. as Modified by Goudar et al. and Wang et al. are described above.
Regarding Claim 24, Mishra et al. teach aeration (introducing air into the bioreactor) at a flow rate of 1.0 L/min in a 5 L bioreactor (page 8, lines 6 and 8-9). It is noted that the unit “VVM” recited in the claim stands for volume of air sparged (in aerobic cultures) per unit volume of growth culture medium per minute. Given the bioreactor has a working volume of 5 L, the aeration flow rate of Mishra et al. may be converted to a flow rate of 0.2 VVM, which falls into the claimed range “0.01 VVM to 0.2 VVM”. Regarding the volume of the bioreactor recited in the claim, Mishra et al. teach a 5-L bioreactor, not a bioreactor of 30 L to 55 L. However, Mishra et al. expressively teach culturing the recombinant CHO cells for a large-scale of TNK-tPA production, and Mishra et al. teach that the TNK products as pharmaceutical agent are safe and effective in treating stroke in patients (abstract). Furthermore, it had been well known in the art to use a bioreactor having the claimed capability for producing proteins/enzymes, as supported by Wang et al., who further teach that the bioreactor can have a working volume of 10 or 50 liters, or any volume in between (col. 11/lines 10-15 and 17). As such, it would have been obvious to further scale up the TNK-tPA production in the method of Mishra et al. by using large bioreactor such as having a working volume from 30 L to 50 L for making more TNK-tPA pharmaceutical products. See MPEP 2144.04(IV)(A), when the size/dimensions do not affect performance/operation, differences in size/dimensions are prima facie obvious.
Regarding the limitation about maintaining a pressure of the bioreactor in the range of “0.1 mbar to 2 mbar” recited in the claim, Mishra et al. are silent about the pressure in the bioreactor. However, it would have been obvious to maintain the pressure of the headspace of the bioreactor in the claimed range in the method suggested by Mishra et al. and other cited prior art for producing TNK-tPA, because the method of Mishra et al. requires aeration of air through the bioreactor to reach a desirable DO level, and it is known in the art that maintaining headspace pressure is associated with proper air aeration and DO establishment in the bioreactor. In support, Dehottay et al. teach a perfusion-based fermentation process, comprising a culturing step involved with aeration of air at a rate of 2 liters of air per minute in the headspace of the bioreactor (equipped with 0.2 mm ATF filter device), where the pressure of the headspace is maintained at 0.1 bar (Example 3, paras 0143/lines 6-8 from bottom, 0086, and 0046/line 3). Dehottay et al. also teach managing the pressure after the dissolved oxygen (DO) reaches its setpoint (para 0046/lines 6-8). It is noted that the 0.1 bar (i.e. 100 mbar) taught by Dehottay et al. does not exactly match the claimed pressure range. However, it is considered that the headspace pressure taught by Dehottay et al. can be readily modified by routine optimization for facilitating aeration and TNK-tPA production in the method suggested by Mishra et al. and other cited prior art. It is well settled that routine optimization is not patentable, even though it results in significant improvement over the prior art (see MPEP 2144.05).
Therefore, the invention as a whole would have been prima facie obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention.
Response to Arguments
Applicant's arguments about the claim objection and rejection under 35 USC 112(a) in the response filed on 03/03/2026 (page 6) have been fully considered but they are moot because they have been withdrawn, as indicated above.
Applicant's arguments about the claim rejection under 35 USC 112(b) in the 03/03/2026 response (page 6) have been fully considered, but they are not persuasive because Applicant’s amendment does not address multiple 112(b) issues in the claims (see pages 5-8 above). For example, in the previous office action it is indicated that the term “preferably” recited in the claims 22, 25, 26, and 28 renders the claims indefinite. However, the claims submitted on 03/03/2026 still contain this term. Applicant is reminded of 37 C.F.R. 1.111, requiring a complete reply to every ground of objection and rejection in the prior Office action.
Applicant's arguments about the rejections of Claims 21-37 under 35 USC 103 in the 03/03/2026 response (pages 7-12) have been fully considered but they are unpersuasive for the reasons indicated below.
In response to Applicant’s arguments about the packed-bed system in bioreactor in the paras spanning pages 7 and 8 of the 03/03/2026 response, Applicant’s arguments are based on the features not recited in the claims. It is noted that the base claim 21 does not recite any limitation to define the structures of the “carrier” or to define how the packed-bed perfusion system is built or connected to the bioreactor. In the base claim 21, the only limitation that defines the packed-bed system of the bioreactor is:“ a bioreactor comprising a packed-bed perfusion system, wherein the packed-bed perfusion system comprises a carrier for providing cell attachment”. The perfusion bioreactor taught by Mishra comprises a packed-bed perfusion system containing carriers for providing cell attachment, thus meeting the claimed limitation.
In response to Applicant’s arguments about Goudar and Wang in the page 8/para 2 – page 9/para 1 (sections b and c) of the 03/03/2026 response, the base claim 1 only describes a carrier for providing cell attachment, but the claim does not recite any limitation to define how many cells in the bioreactor are attached to the carrier and the claim does not require cells in the perfusion cell culture are not present as a liquid cell suspension; and although the claim 21 recites a bioreactor comprising packed-bed system comprising a carrier in the preamble of the claim, the claim does not even require the cell culturing to be carried out in this bioreactor in the culturing step i). Further, It is noted that perfusion cell cultures are essentially performed in bioreactor comprising a cell-retention device (i.e. a carrier immobilized or packed-bed platform) to allow continuously circulating culture medium throughout the bioreactor while cells are maintained inside or with the bioreactor. Both Goudar and Wang teach a continuous perfusion process in perfusion bioreactors comprising matrix carriers/filters for cell retention/attachment and carrying out a perfusion cell culture, Not a conventional suspension culture, for producing recombinant proteins in CHO cell line. As such, the high cell density cultures (>140x106) as well as the CSPR ranges (10-150, 15-31.5, and 30-80 pL/cell/day) taught by Goudar and Wang are specifically adapted to a perfusion cell culture behavior and are readily applicable to the perfusion cell culture in the process of Mishra for producing recombinant TNK-tPA in CHO cell line. In addition, Goudar and Wang teach that their the perfusion cultures are coupled to real time capacitance-guided system for controlling cell densities in carrier/filter-immobilized operation. With regard to Applicant’s arguments based on the “distinct mass-transfer, hydrodynamics, and retention mechanisms” of the claimed fixed bed system, these arguments are not persuasive because Applicant failed to provide any factual evidence to support the claimed system is distinct from those taught by the cited prior art.
In response to Applicant’s continuous arguments about Goudar in section d) of page 9 of the 03/03/2026 response, the capacitance pF/cm values taught by Goudar are for perfusion cell cultures, NOT for a conventional cell suspension, in a perfusion bioreactor comprising carrier/filter-immobilized system for cell retention/attachment, as indicated above. Examiner further reminds Applicant that either the instant claims or the specification describe using capacitance for controlling cells immobilized on or attached to the carrier, and the “great than 140x106” recited in the claim 21 is directed to the cell density of the perfusion cell culture in the bioreactor, NOT to the immobilized cells or fixed bed density on the carrier.
In response to Applicant’s arguments in the sections e), g), and i) in pages 9-11 of the 03/03/2026 response, it is noted that the additional limitations in the claim 30 are directed only to the extraction step vi) recited in the base claim 21, and these limitations are not relevant to the culture steps and the CSPR/cell density in the claim. In addition, the instant claims do not recite any limitations to define that TNK-tPA in the step vi) is extracted from cells immobilized on the carrier in the packed-bed system, Not from a filtrate obtained from filtering perfusion cell cultures (i.e. a liquid culture medium from the bioreactor). Regardless of how the perfusion cell culture process of Zhou is carried out, Zhou teaches it is effective to use the claimed two-phase continuous filtration system for filtering perfusion cell cultures (liquid culture medium) and isolating/extracting secreted proteins from the obtained filtrate, which is readily adapted to the extraction step in the method of Mishra. As such, the claim 30 would have been obvious over the further teachings of Zhou for the reasons indicated in the 103 rejection above. Furthermore, the cited prior art suggests a method having the claimed combination of duration, cell density, CSPR, and capacitance while using a carrier/filter immobilized operation, for the reasons indicated above and the reasons indicated in the 103 rejections above. Moreover, Zhou teaches perfusion cell cultures in a perfusion bioreactor that comprises cell-retention carrier/device so as to allow perfusion processes to be carried out, as indicated above. As such, the capacitance range in the perfusion cell culture processes of Zhou is applicable to the perfusion cell culture processes taught by Mishra.
In response to Applicant’s arguments in the section h) in page 10 of the 03/03/2026 response, Applicant’s arguments about Kaufman are based on the features not recited in the claims. It is noted the base claim 21 does not recite any limitation to define a specific scale of the system or a specific volume of the bioreactor. As such, the 1.6 L small scale system taught by Kaufman is encompassed by the instant claims and the teachings of Kaufman meet the claimed limitations. With regard to Applicant’s arguments based on specific CSPR, cell density, duration, and capacitance management recited in the base claim 21, Applicant failed to provide factual evidence from the prior art to support that the packed-bed basket containing polyester non-woven fabric carriers cannot be used in a bioreactor when CSPR, cell density, and duration fall into claimed ranges, or when capacitance is used for managing cell growth. With regard to Applicant’s arguments based on the claimed fixed-bed integration and process windows, these arguments are based on the features not recited in the claims. Examiner reminds Applicant that the base claim 21 and the claim 30 do not recite any limitations to define how the packed-bed perfusion system is integrated into the bioreactor and how it is operated in the claimed method.
In response to Applicant’s arguments in the section j) of page 11 of the 03/03/2026 response, it is noted that the CSPR range in the perfusion cell culture process taught by Wang is readily applicable to the process of Mishra, because both processes are perfusion cell culture processes, as indicated above. This is Examiner’s position that the claims 31 and 32 would have been obvious over the further teachings of Wang and other cited prior art, in the absence of evidence to support a combination of the claimed cell density, CSPR and duration in the claimed method are critical for TNK-tPA production.
Overall, the conclusion of the obviousness of the newly submitted claims 21-37 has been established for all the reasons indicated above.
Conclusion
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 extension fee 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 date of this final action.
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Any inquiry concerning this communication or earlier communications from the examiner should be directed to Qing Xu, Ph.D., whose telephone number is (571) 272-3076. The examiner can normally be reached on Monday-Friday from 9:30 AM to 5:00 PM. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Manjunath N. Rao, can be reached at (571) 272-0939.
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/Qing Xu/
Patent Examiner
Art Unit 1656
/MANJUNATH N RAO/Supervisory Patent Examiner, Art Unit 1656
Prosecution Insights