DETAILED ACTION
Receipt of Arguments/Remarks filed on October 8 2025 is acknowledged. Claims 3, 6, 8, 10-11, 19, 21-22, 25 and 30-32 were/stand cancelled. Claims 1-2, 4-5, 7, 9, 12-13, 15-18, 20, 24, 26 and 28-29 were amended. Claims 1-2, 4-5, 7, 9, 12-18, 20, 23-24 and 26-29 are pending.
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 .
Withdrawn Rejections
The amendments filed October 8 2025 are sufficient to overcome the rejection of claims 26-27 under 35 USC 112(b). The dependency has been corrected.
Modified Rejection Based on Amendments in the reply filed on October 8 2025
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 of this title, 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 set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-2, 4-5, 7, 9, 12, 14-18, 20, 23-24 and 26-28 are rejected under 35 U.S.C. 103 as being unpatentable over O’Connor et al. (WO2020163454) in view of Costariol et al. (Biotechnol. J. 2020, cited on PTO Form 1449) and Villiger et al. (USPGPUB No. 20190085284) as evidenced by Lim et al. (USPGPUB No. 20160024460).
Applicant Claims
The instant application claims a method of producing a T-cell culture in a fully closed system, comprising: a) obtaining an T-cell; b) introducing the T-cell into a stirred-tank bioreactor comprising an T-cell complete medium; c) activating the T-cell with an activation reagent to produce an activated T-cell in the stirred-tank bioreactor; d) expanding the activated T-cell to produce an expanded T-cell culture in the stirred-tank bioreactor; e) exchanging a defined amount of fresh medium for spent medium via an alternating tangential flow filtration (ATF) connected to the bioreactor; f) depleting the expanded T-cell culture of (d) to produce a depleted T-cell culture in the stirred-tank bioreactor; g) harvesting the depleted T-cell culture of (f) to produce a harvested T-cell culture in the fully closed system; and h) concentrating the harvested T-cell culture of (g) in the fully closed system, wherein the method results in less than 1% loss of the T-cell culture.
Determination of the Scope and Content of the Prior Art
(MPEP §2141.01)
O’Connor et al. is directed to a cell concentration methods and devices for use in automated bioreactors. The cassettes and methods are utilized and carried out in a fully enclosed automated cell engineering system (paragraph 0028). A user can provide an automated cell engineering system pre filled with a cell culture and reagents (e.g., an activation reagent, a vector, cell culture media, nutrients, selection reagent, and the like) and parameters for the cell production (e.g., starting number of cells, type of media, type of activation reagent, type of vector, number of cells or doses to be produced, and the like). The automated cell engineering system is able to carry out the various automated methods, including methods of producing genetically modified immune cell cultures, including CAR T cells, without further input from the user (paragraph 0029). Fig. 1 shows various processes can be carried out in an enclosed, automated system. The processes include activating, transducing, expanding, concentration, washing and collecting/harvesting steps (paragraph 0026). In order to receive the greatest cell recovery without significant loss in viability, process parameters are optimized (paragraph 00168).
Ascertainment of the Difference Between Scope the Prior Art and the Claims
(MPEP §2141.02)
While O’Connor et al. teaches an enclosed system for use in automated bioreactors, O’Connor et al. does not expressly teach a stirred-tank bioreactor. However, this deficiency is cured by Costariol et al.
Costariol et al. teach the manufacture of human CAR-T cells in an automated stirred-tank bioreactor. When selecting a suitable expansion platform for cell production, it is important to consider multiple factors to mitigate clinical and commercial risk. Stirred-tank bioreactors (STRs) have significant potential advantages. The provide a robust cell expansion platform, they are widely used in the biological industry, they have well characterized and proven high-thruput small-scale models, they have well-established supply chain infrastructure and have an existing and well established pathway to enable full process integration (page 1-2, last paragraph and left column). The study demonstrated the expansion of CAR-T cells in a STR (conclusions).
While O’Connor et al. teaches a tangential flow filtration for T-Cells, O’Connor et al. does not teach alternating tangential flow filtration or pluripotent stem cells. However, this deficiency is cured by Villiger et al.
Villiger et al. is directed to the production of extracellular vesicles in single-cell suspension using chemically-defined cell culture media. Taught are culturing cells in a bioreactor such as a stirred-tank bioreactor. A stirred-tank bioreactor is connected to a cell retention device such as hollow fibrous membrane run in alternating tangential flow filtration (ATF), tangential flow filtration (TFF) or an acoustic cell separator (paragraph 00077). Parent cells which can be utilized include erythrocytes, platelets, neutrophils, stem cells including cells derived from pluripotent stem cells (paragraph 0088).
Finding of Prima Facie Obviousness Rationale and Motivation
(MPEP §2142-2143)
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to combine the teachings of O’Connor et al., Costariol et al. and Villiger et al. and utilize a stirred-tank bioreactor. One skilled in the art would have been motivated to utilize a stirred-tank bioreactor for the numerous advantages taught by Costariol et al. One skilled in the art would have a reasonable expectation of success as O’Connor et al. teaches the use of bioreactors with CAR-T cells which is the same type of cells used in Costariol et al.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to combine the teachings of O’Connor et al., Costariol et al. and Villiger et al. and utilize alternating tangential flow filtration. It would have been obvious to one skilled in the art to utilize either ATF or TFF as both are taught as being suitable to be used with stirred-tank bioreactors as taught by Villiger et al. Since O’Conner et al. teaches the use of TFF and a pump there is a reasonable expectation of success.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to combine the teachings of O’Connor et al., Costariol et al. and Villiger et al. and utilize any desirable parent cell. Since the method is designed to culture cells it would have been obvious to one skilled in the art to utilize any known cell types such as pluripotent stem cells as all are taught as suitable by Villiger et al.
Regarding claim 1, O’Connor et al. teaches pre filled with a cell culture and reagents (e.g., an activation reagent, a vector, cell culture media, nutrients, selection reagent, and the like) reading on obtaining an immune cell (CAR T-Cell) and introducing the immune cell into a stirred-tank bioreactor comprising the immune cell complete medium, activating the immune cell with an activation reagent. Fig. 1 shows processes of expanding, concentrating and harvesting. The systems are monitor. Taught is providing fresh media and/or nutrients to the cell culture (paragraph 0089) reading on the instantly claimed exchanging. Exemplified are the use of tangential flow filtration which can be used to separate, clarify, recover and collect cells from a post-harvest suspension fluid reading on depleting.
Regarding claim 2, O’Connor et al. teaches that a culture media with nutrients (paragraph 0029). Costariol et al. teaches Dulbecco’s Modified Eagle Medium (DMEM) (experimental section). As evidenced by Lim et al., DMEM includes amino acids, inorganic salts, trace elements, glucose, buffers, serum, vitamins (paragraph 0040).
Regarding claim 4, O’Connor et al. in Fig 8A-8B shows reduction of peripheral blood mononuclear cells (PBMC). As taught by Costariol et al., T-cells (immune cells) were isolated form fresh peripheral blood mononuclear cells (experimental section).
Regarding claim 7 and 18, O’Connor et al. teaches a magnetic separation process can be utilized to further eliminate and separate undesired cells and debris from a cell population. In such embodiments, a magnetic bead or other structure, to which a biomolecule (e.g., antibody, antibody fragment, etc.) has been bound, can interact with a target cell. Various magnetic separation methods, including the use of filters, columns, flow tubes or channels with magnetic fields, etc., can then be used to separate the target cell population from undesired cells, debris, etc., that may be in a cellular sample. For example, a target cell population can flow through a tube or other structure and be exposed to a magnetic field, whereby the target cell population is retained or held-up by the magnetic field, allowing undesired cells and debris to pass through the tube. The magnetic field can then be turned off, allowing the target cell population to pass onto a further retention chamber or other area(s) of the cassette for further automated processing.
Regarding claim 9, O’Connor et al. teaches that the cell concentration during the process varies from 0.3*106 cells/ml to approximately 10*106 cells/ml (paragraph 0068). Costariol et al., teaches that viability and live cell concentration was accessed daily (section 2.1). Since O’Connor et al. teaches that process conditions can be optimized, one skilled in the art would manipulate the process conditions in order to achieve the desired level of viability and cell concentration.
Regarding claim 12, O’Connor et al. teaches chambers with the activation agent is maintained at a temperature for growing cells (e.g. at about 37 °C) (paragraph 0056; 0088). Costariol et al. also teaches activation at 37 °C (section 5). While both O’Connor et al. and Costariol et al. are silent to the exact time, one skilled in the art would recognize that depending on the activation agent utilized or level of activation required, one skilled in the art would incubate the cells at 37 °C for the necessary amount of time to achieve the desired activation level
Regarding claim 13, Villiger et al. teaches agitation conditions for culturing to ensure proper aeration at sufficiently high cell densities can vary and depend upon cell type, type of culture vessel, volume of culture, etc. Agitation can be achieved by stirring or shaking. In certain embodiments, the speed of shaking ranges from 350 rpm and 10 rpm, or ranges from 300 rpm and 50 rpm, or ranges from 275 and 150 rpm, or ranges from 250 and 200 rpm. In certain embodiments, the speed of shaking is 250 rpm. In certain embodiments, the speed of agitation will vary according to cell culture volume, shaking diameter and/or if the culture vessel is tilted or cultured at 90 degree angle (paragraph 0058). O’Connor et al. teaches that in order to receive the greatest cell recovery without significant loss in viability, process parameters are optimized. Therefore, one skilled in the art would manipulate the process parameters in order to determine the optimal stirring speed.
Regarding claim 14, Costariol et al. teaches a pH between 7.3-7.4. O’Connor et al. describes the use of a pH sensor (see figures). Therefore, one skilled in the art would use a medium which achieves the desired pH for activation.
Regarding claim 15, O’Connor et al. teaches PBMC were stimulated with Dynabeads and then expanded in complete T-cell media. A pre-wash protocol has been used (paragraph 00156). O’Connor et al. teaches the cassettes include one or more of a pH sensor 524, a glucose sensor (not shown), an oxygen sensor 526, a carbon dioxide sensor (not shown), a lactic acid sensor/monitor (not shown), and/or an optical density sensor (not shown). See FIG. 5 for exemplary positions within the flowpath (0054). Uses these systems to monitor is suggested (paragraph 0089).
Regarding claims 16-17, O’Connor et al. teaches the automated cell engineering system automatically adjusts the schedule of cell feeding (i.e. , providing fresh media and/or nutrients to the cell culture) based on the cell growth rate and/or cell count, or other monitored factors, such as pH, oxygen, glucose, etc. The automated cell engineering system may be configured to store media (and other reagents, such as wash solutions, etc.) in a low-temperature chamber (e.g., 4°C or -20°C), and to warm the media in a room temperature chamber or a high-temperature chamber (e.g., 25°C or 37°C, respectively) before introducing the warmed media to the cell culture (paragraph 0089). Therefore, O’Connor et al. teaches that the system adjusts depending on the results of the monitored factors. One skilled in the art would determine the devel of viable cell density required.
Regarding claim 20, O’Connor et al. teaches a cellular sample output can be utilized to harvest the cells (paragraph 0042). Tangential flow filtration can be used for harvesting (example 1). Taught is the use of a pump system (paragraph 0034) and the flow controller is an additional pumping system (claim 50). Villiger et al. suggests the use of ATF.
Regarding claim 23, Costariol et al. teaches harvest at 7 days. O’Connor et al. teaches that the system recirculates through until such time as collection is desired (paragraph 0049). Therefore, one skilled in the art would determine when harvesting/collecting is desired and harvest the cells at that time.
Regarding claim 24, 26-28, O’Connor et al. teaches centrifuged (examples) and generally teaches filtration (examples). Costariol et al. also teaches centrifuged (section 5). O’Connor et al. teaches that in order to receive the greatest cell recovery without significant loss in viability, process parameters are optimized. While concentration, the pump was set to 60 ml/min and the permeate control pump was set to either 0, 5, 10, or 15 ml/min. Villiger et al. teaches the use of hollow fiber filters (TFF or ATF) or an acoustic cell separator (paragraph 0037). Therefore, since O’Connor et al. expressly teaches that the process parameters are optimized in order to achieve the greatest cell recovery without significant loss in viability, absent a demonstration of the criticality, one skilled in the art would manipulate the flow rate and processing conditions in order to achieve the desired result. O’Connor et al. teaches passage into storage (paragraph 0034; 0042) and the closed system allows the processes to be formed aseptically (paragraph 0142) resulting in a sterile and enclosed container.
Claim 29 is rejected under 35 U.S.C. 103 as being unpatentable over O’Connor et al. in view of Costariol et al. and Villiger et al. as evidenced by Lim et al. as applied to claims 1-2, 4-5, 7, 9, 12-18, 20, 23-24 and 26-28 and in further view of Castella et al. (Frontiers in Immunology, 2020, cited on PTO Form 1449).
Applicant Claims
The instant application claims the activating and the expanding of the T-cell in the stirred-tank bioreactor results in a T-cell culture producing greater than five cytokines, and with greater than 75% central memory T-cells, less than 10% effector memory T-cells, and greater than 10% naïve/stem memory T-cells.
Determination of the Scope and Content of the Prior Art
(MPEP §2141.01)
The teachings of O’Connor et al., Costariol et al. and Villiger et al. are set forth above.
Ascertainment of the Difference Between Scope the Prior Art and the Claims
(MPEP §2141.02)
O’Connor et al. does not expressly teach the limitations of instant claim 29. However this deficiency is cured by Castella et al.
Castella et al. is directed to point-of-care CAR T-cell production using a closed semi-automatic bioreactor. Castella et al. discloses development of semi-automated devices that can reduce the hands-on time and standardize the production of clinical grade CAR T-cells (abstract), wherein the resulting immune cell population comprises a T-cell culture producing greater than five cytokines (Figure S5; Figure S5 Legend : "Cytokine levels measured from supernatants of co-culture experiments of final products with NALM6 cells at different E:T ratios. Cytokine levels were measured by Luminex. Graphs show mean ± SEM": Note: Figure S5 illustrates the expression of IL-10, IL-12, IL-17, IL-1b, IL-2, IL-4, IL-6, IP-10, IL-15, IL-8, and MiP1A), and with greater than 31% central memory T-cells, a specific % of effector memory T-cells, and greater than 10% naive/stem memory T-cells (pg 7, col 2, para 2 - "Average percentage and SD for each
subpopulation in the CAR+ cells of the final product is as follows: TN: 7.71 ± 13.9, TSCM: 5.26 ± 12.0, TCM: 31.01 ± 16.7, TEM: 35.11 ± 17.7, and TE: 4.2 ± 9.5").
Finding of Prima Facie Obviousness Rationale and Motivation
(MPEP §2142-2143)
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to combine the teachings of O’Connor et al., Costariol et al., Villiger et al. and Castella et al. and manipulate the activating and expanding of the immune cells to achieve the desired T-cell populations. Since both O’Connor et al. and Castella et al. are directed to CAR T-cells and Castella et al. show cytokine levels, central memory T-cell level, effector memory T-Cell level and naïve/stem memory T-Cell levels there is a reasonable expectation of success.
Response to Arguments
Applicants’ arguments filed October 8 2025 have been fully considered but they are not persuasive.
Applicants argue (page 7-8) that (1) a person having ordinary skill in the art would not have a reason to combine the disclosures of O-Connor, Costariol and Villiger with a reasonable expectation of success. It is argued that the instant specification (paragraph 0073) states that the 5-10 µm diameter of T cells creates issues with T cell culture perfusion and that tangential flow filtration enables media perfusion without filter fouling. An advantage of using ATF for T-cell culture perfusion is the self-cleaning induced back flush of the alternating flow and it was surprisingly found that the use of ATF resulted in no notable decrease in the viable cell density and absence of T-cells in the waste bag. Villiger is wholly silent to perfusion culturing methods for T-cells. One skilled in the art would not look to the disclosure of Villiger for perfusion culturing methods for T-cells. Even if one skilled would look to Villiger, which Applicants don’t agree, Villiger discloses that TFF and ATF are both suitable. Villiger does not disclose any advantage in using ATF over TFF. Thus there is no reason to switch from the use of TFF to ATF. Costariol does not discuss the use of ATF. Lim does not overcome the aforementioned deficiencies.
Regarding Applicants’ first arguments, while Villiger et al. does not expressly teach T-Cells this is not the requirement for an obviousness rejection. The test for obviousness is not whether the features of a secondary reference may be bodily incorporated into the structure of the primary reference; nor is it that the claimed invention must be expressly suggested in any one or all of the references. Rather, the test is what the combined teachings of the references would have suggested to those of ordinary skill in the art. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981). Furthermore it is not necessary to show that a combination is the best option, only that it be a suitable option. Note: MPEP 2144.07. As recognized by Applicants Villiger discloses that TFF and ATF are both suitable. This suggests that either can be used. Therefore, the lack of an express teaching of T-cells in Villiger et al. does not negate the teachings that either ATF or TFF can be used. Since O’Connor et al. teaches TFF and Villiger et al. teaches either ATF or TFF can be used there is motivation within the cited prior art to substitute one known filtration with another. Note: MPEP 2143: examples of rationales (B) simple substitution of one known element for another to obtain predictable results. While it is not necessary that the prior art teaches the ATF for the same advantages found by Applicants, the examiner cannot agree that this is an unexpected effect. As taught by Wang et al. (Journal of Biotechnology 2017), the pump used in typical TFF perfusion systems is shown to be the single major contributor to shear stress and cell lysis. Replacing the peristaltic pump with a low shear centrifugal pump brought cell growth, cell lysis, particle concentration and product sieving in a TFF perfusion system to levels comparable to that of an ATF (abstract). ATF has gained popularity for its claims of better product recovery. ATF performs better in terms of cell growth, viability and most importantly product recovery and membrane fouling (page 53, first two paragraphs). Therefore, the art recognizes this advantage of ATF such that applicants discovery is not unexpected nor surprising.
Applicants argue (page 9) that (2) Castell does not overcome the aforementioned deficiencies. Castella does not disclose any reason to utilize ATF over TFF.
Regarding Applicants’ second argument, this argument is not persuasive for the reasons set forth 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 nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/ABIGAIL VANHORN/ Primary Examiner, Art Unit 1636
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