DETAILED ACTION
Applicant’s amendment and Arguments/Remarks received on 11 August 2025 have been entered. Claims 115-122, 124, 127-128, 133-135, and 137-143 were previously pending in the application. Claims 127 and 142 have been newly cancelled, and new claims 144-147 have been added by Applicant. Claims 115-122, 124, 128, 133-135, 137-141, and 143-147 are currently pending in the application. Claims 115, 122, 141, and 147 are independent claims. The election of Group I, drawn to a composition comprising one or more nucleic acids encoding a first chimeric antigen receptor (CAR) and second CAR; a CAR T cell comprising the composition comprising one or more nucleic acids encoding a first chimeric antigen receptor (CAR) and second CAR; and a method of treating, inhibiting, or ameliorating a cancer in a subject comprising administering the CAR T cell comprising the composition comprising one or more nucleic acids encoding a first chimeric antigen receptor (CAR) and second CAR, remains in effect in the instant application. The following election of species remains in effect in the instant application:
CAR T cell type: a CD3+ cell
Hapten: fluorescein
Hapten antigen presenting cell (H-APC) type: a monocyte.
Claims 121 and 137 remain withdrawn from consideration as being directed to a nonelected species. Claims 115-120, 122, 124, 128, 133-135, 138-141, and 143-147 are currently pending and under examination in the instant application. An action on the merits follows.
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Priority
The present application is a 35 U.S.C. 371 national stage filing of International Application No. PCT/US2019/44981, filed 02 August 2019, which claims priority to U.S. Provisional Application No. 62/714,928, filed 06 August 2018.
Thus, the earliest possible priority for the instant application is 06 August 2018.
Information Disclosure Statement
The information disclosure statement filed 11 August 2025 has been considered by the Examiner. The filing of an IDS Size Fee Assertion under 37 CFR 1.98, indicating that no IDS size fee is believed due under 1.17(v) at this time, is acknowledged.
Claim Rejections - 35 USC § 112(b)
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Amended and new claims 122 are newly 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 applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Amended independent claim 122 has multiple issues of indefiniteness.
Amended independent claim 122 newly recites the limitation "the hapten" in lines 17 and 19. There is insufficient antecedent basis for this limitation in the claim. Claim 122 recites “a hapten” in both 12 and 16, and so it is unclear which hapten “the hapten” is referring to.
Claim 122 additionally recites a method of treating, inhibiting, or ameliorating a cancer in a subject comprising administering to the subject an effector cell comprising a first CAR comprising a ligand binding domain specific for a tumor antigen, which is indefinite because it is unclear the tumor antigen is meant to be a tumor antigen expressed by tumor cells of the cancer in the subject, or whether the tumor antigen is meant to encompass any tumor antigen expressed by any tumor cells of any cancer in any subject.
As such, the metes and bounds of the claim cannot be determined.
New claim 144 recites “a length of 1 to 16 PEG subunits” in line 2, which is indefinite because it is unclear how many ethylene glycol monomers are meant to be encompassed in each “PEG subunit” in that to be a polyethylene glycol, it must have at least 2 monomers of ethylene glycol. The specification does not provide a limiting definition of a “PEG subunit” which would define the size or structure of the “PEG subunit”. The specification merely teaches that a PEG spacer comprises 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16 “PEG molecules” [0174], which does not indicate the number of ethylene glycol monomers present within the polyethylene glycol (PEG) molecules/subunits which make up the PEG spacer. As such, the metes and bounds of the claim cannot be determined.
Note that new claim 146 is included in this rejection because the support for “n is 1 to 16” appears to rely on the same passage in the specification merely teaching that a PEG spacer comprises 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16 “PEG molecules” [0174] in that the description in Figure 3A does not specify a value for n within the structure of formula (I). As such, the metes and bounds of the claim cannot be determined.
New independent claim 147 recites, “wherein the PEG spacer had a length of 1 to 16 subunits” in lines 11-12, which has multiple issues of indefiniteness.
Firstly, “a length of 1 to 16 PEG subunits” is indefinite because it is unclear how many ethylene glycol monomers are meant to be encompassed in each “PEG subunit” in that to be a polyethylene glycol, it must have at least 2 monomers of ethylene glycol. The specification does not provide a limiting definition of a “PEG subunit” which would define the size or structure of the “PEG subunit”. The specification merely teaches that a PEG spacer comprises 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16 “PEG molecules” [0174], which does not indicate the number of ethylene glycol monomers present within the polyethylene glycol (PEG) molecules/subunits which make up the PEG spacer.
Secondly, recitation of “had” is indefinite because it is unclear whether the PEG spacer is meant to have the 1 to 16 PEG subunits at the time of administer of the H-APC to the subject, at the time of integration into the plasma membrane of the H-APC, or at some other time. Additionally, if the PEG spaces is meant to no longer have a length of 1 to 16 PEG subunits at the time of preparation of the H-APCs and/or administration of the H-APCs to the subject, it is unclear how many PEG subunits the spacer is meant to have at the time of administration of the H-APCs.
As such, the metes and bounds of the claim cannot be determined.
Claim Rejections - 35 USC § 103
The rejection of amended, previously presented, and cancelled claims 115-120, 122, 124, 127-128, 133-135, and 138-143 under 35 U.S.C. 103 as being unpatentable over Ruella et al. [2016, J. Clin. Invest., Vol. 126(10), 3814-3826]; in view of Imai et al. [2004, Leukemia, Vol. 18, 676-684]; Bio-Rad [2016, The T Cell Marker, CD3 Antigen and Antibodies, retrieved on 4 May 2024 from the Internet: <URL: https://www.bio-rad-antibodies.com/static/2016/innate/the-t-cell-marker-cd3-antigen-and-antibodies.pdf>]; Kim et al. [US20180100026A1, published 12 April 2018]; Hadrup et al. [WO2018115146A1, published 28 June 2018]; Dissanayake et al. [2014, PLoS ONE, Vol 9(3), 1-10]; McEnaney et al. [2012, ACS Chem. Biol., Vol. 7, 1139-1151]; Kozer et al. [2011, Physical Biology, Vol. 8, 066002, 1-13]; and Rushworth et al. [2014, Journal of Immunotherapy, Vol. 37(4), 204-213]; is withdrawn over cancelled claims 127 and 142, maintained over amended claims 115-120, 122, 124, 128, 133-135, 138-141, and 143, and newly applied to new claim 146. Applicant's amendments to the claims and arguments have been fully considered but have not been found persuasive in overcoming the rejection for reasons of record as discussed in detail below.
Applicant amended independent claim 115 to recite, “wherein the hapten is selected from fluorescein, urushiol, quinone, biotin, and dinitrophenol, or a derivative thereof; wherein the second CAR of the effector cell is capable of directly binding the hapten of the H-APC”.
As discussed in the prior action, Kim was cited for teaching a CAR comprising a region that interacts with a fluorescein hapten (e.g., an anti-FITC scFv), wherein the CAR of the CAR-T cell directly binds the fluorescein hapten [Figure 1]. Kim was further cited for teaching wherein interaction with fluorescein directs the CAR T cell to interact with a target cell, such as a monocyte, allowing the interaction to be induced by addition of the fluorescein/hapten-conjugated switch and quenched by termination of switch doses, thereby preventing adverse effects, such as targeting of normal tissues or cells [0004, 0005, 0257, 0500, Figures 1, 61], thereby teaching the motivation to use a CAR T cell comprising a CAR which binds to a hapten, such as fluorescein, to allow greater control of the CAR T cell activity following administration to a patient.
Applicant amended claim 117 to specify that the cleavable linker is located between the first sequence encoding the first CAR and the second sequence encoding the second CAR.
Ruella was cited for teaching a first nucleic acid comprising the first sequence encoding the first CAR and a second nucleic acid comprising the second sequence encoding the second CAR [column 15 paragraph 2] and a bicistronic nucleic acid comprising the first sequence encoding the first CAR and the second sequence encoding the second CAR with a P2A ribosome skip sequence between the first and second sequence [column 15, paragraph 2, Figure 5].
Applicant amended independent claim 122 to recite the limitations of independent claim 115 for the effector cell and H-APC in the method of treating, inhibiting, or ameliorating a cancer in a subject in place of encompassing the system of claim 120, but has not introduced any limitations which are not presently recited in independent claim 115. As such, all limitations of amended claim 122 have been addressed in the prior action and/or above.
Applicant amended claim 124 to specify that the stimulating the effector cell by contacting the effect cell with the H-APC in vitro is prior to administering the effector cell.
Ruella was cited for teaching the step of activating the CAR T cell by incubation with APCs (e.g., CD19+ K562 cells, CD123+ K562 cell, or CD19+/CD123+ B-ALL cells) in vitro or in vivo [column 15 paragraph 2-column 16 paragraph 1, Figures 2, 5-6].
Hadrup was additionally cited for teaching an artificial APC scaffold comprising a fluorescein hapten which is specifically designed to stimulate and expand anti-hapten CAR T cells when incubated with the CAR T cells in vitro and in vivo [page 11 line 5, page 14 lines 1-8, page 17 lines 8-12, page 19 line 25-page 20 line 2, page 23 lines 6-33, page 48 lines 11-18, page 53 lines 20-33, page 57 lines 20-page 58 line 3, Figure 19]. Hadrup also teaches that the aAPC scaffold of their invention is used in the expansion of tumor-reactive T cells for use in adoptive cell transfer (ACT), such that the strength of the ACT strategy is that T cells are present ex vivo in an environment that is optimal for efficient expansion of an antigen-specific T cell population [page 28 line 32- page 29 line 2], such that T cells are extracted from a subject, expanded ex vivo, and the expanded T cell population reintroduced into the subject [page 36 lines 27-34]. Therefore, an ordinarily skilled artisan at the time of filing the instant application would have been motivated to stimulate the effector cells by contacting the effector cell with the H-APC ex vivo/ in vitro prior to administering the effector cell to a patient to efficiently expand the antigen-specific T cell population.
Applicant amended claim 139 to recite “wherein the measuring is performed after providing the effector cell to the subject, wherein the reduction in effector cell activity comprises a reduction in an amount of the effector cell in the subject”.
As discussed in the prior action, Ruella also teaches measuring a reduction in effector cell activity in the subject over time following administration of the effector T cell to the subject [Figure 3-4, 6].
Additionally, Kim teaches monitoring the peripheral blood T cell count in subjects following administration of the CAR-T cells and the fluorescein-antiCD19 switch, wherein the amount of the effector CAR-T cells in the subject decline over time following administration of the effector T cell to the subject [0510, 0521, Figure 66B]. Kim also teaches that the in vivo CAR-T cell activity and expansion can be controlled by hapten switch dose [0510]. Kim further teaches to compare CAR effector cells proliferation following administration of a dose of switch and continuing administering additional doses after comparing if needed [0425]. Kim also teaches that persistence of CAR-T cells is critical to enable redosing strategies in the case of relapse, and that persistence may be promoted through rest phases in which switch dosing is withheld to prevent exhaustion related to persistent T cell signaling, and as such, the methods may further comprise comparing effector memory T cell quantity in the subject before administering the first/ second switch to the subject to after administering the first/second switch to the subject [0425]. Therefore, Kim teaches the motivation to assess the persistence of CAR-T effector cells in a subject after administration of the effector cells to the subject, wherein additional doses of stimulant can be administered to promote persistence of the effector cells.
Regarding new claim 146, Kozer was cited for teaching covalently attaching a fluorescein molecule (FITC) to a 1,2-dihexadecanoyl-sn-glycero-3-phospho-ethanol-amine (DHPE) phospholipid and integrating the FITC-DHPE into the plasma membrane of a cell to label the cell such that the fluorescein molecules are presented on the surface of the cell, wherein the FITC-DHPE has the structure of Formula (II), e.g., N-(Fluorescein-5-Thiocarbamoyl)-1,2-Dihexadecanoyl-sn-Glycero-3-Phosphoethanolamine [column 6 ¶ 3, Table 1, Figure 2]. Therefore, an ordinarily skilled artisan at the time of filing the instant application would have had a reasonable expectation of success in attaching a fluorescein hapten to the cell surface by attaching the fluorescein to a DHPE phospholipid with the structure of formula (II). Additionally, given the teachings of Kozer that this attachment allows the labeling of the surface of a cell with the FITC, and the motivation taught by McEnaney, as discussed in the prior action, to utilize a fluorescein hapten to covalently label the extracellular surface of cells to induce an antibody/ ligand binding interaction with a T cell, an ordinarily skilled artisan at the time of filing the instant application would have been motivated to use the FITC-DHPE of formula (II) to induce an antibody/FITC binding interaction with a T cell.
Accordingly, given the motivation taught by Kim to use a CAR T cell comprising a CAR which binds to a hapten, such as fluorescein, to allow greater control of the CAR T cell activity following administration to a patient; the motivation taught by Hadrup to stimulate the effector cells by contacting the effector cell with the H-APC ex vivo/ in vitro prior to administering the effector cell to a patient to efficiently expand the antigen-specific T cell population; the additional motivation taught by Kim to assess the persistence of CAR-T effector cells in a subject after administration of the effector cells to the subject, wherein additional doses of stimulant can be administered to promote persistence of the effector cells; and the motivation taught by Kozer to use the FITC-DHPE of formula (II) to induce an antibody/FITC binding interaction with a T cell; it would have been prima facie obvious to an ordinarily skilled artisan to modify the system and methods of Ruella to use a CAR-T effector cell comprising a CAR which binds a hapten, such as fluorescein, to stimulate the effector cell by contacting the effector cells with a fluorescein-specific H-APC ex vivo/ in vitro prior to administering the effector cell to a patient, to assess the persistence of the CAR-T effector cells in a subject after administration of the effector cells to observe a reduction in the amount of CAR-T effector cells in the subject, and to use the FITC-DHPE of formula (II) to attach the fluorescein hapten to the surface of the H-APC with a reasonable expectation of success.
Applicant argues that:
The cited references, alone or in combination, do not teach or suggest all claim limitations, wherein Ruella, Imai, Bio-Rad, Hadrup, Dissanayake and Rushworth fail to teach or suggest a system comprising an effector cell and an H-APC cells, the effector cell comprising a CAR specific for a hapten selected from those recited in claim 115, and that Kim, McEnaney, and Kozer do not remedy the defects of Ruella, Imai, Bio-Rad, Hadrup, Dissanayake and Rushworth, specifically that:
Kim teaches indirect binding between an anti-fluorescein CAR T cell and a protein antigen via a macromolecular bridging molecule, such that Kim does not teach or suggest that the effector cell directly binds to a hapten as required by the present claims;
McEnaney teaches known, synthetic, antibody-recruiting molecules (ARMs) which are bifunctional molecules capable of inducing antibodies to bind cells, such that McEnaney does not teach a system comprising an effector cell that directly binds a hapten; and
Kozer only teaches a conjugate that can bind to sugars on a cell and does not teach or suggest an effector cell that directly binds a hapten;
The cited references, alone or in combination, do not provide the requisite motivation to modify or combine the references to arrive at the present claims, specifically that
there is no motivation in Hadrup and Rushworth, alone or in combination, what would lead a skilled artisan to the claimed system where the effector cell is activated through two antigens since the combination of Hadrup and Rushworth causes the art to become inoperable or destroy its intended function, in that the combination would require substantial reconstruction and redesign and change the basic principles under which the reference teachings were designed to operate since Hadrup teaches use of multiple stimulatory molecules whereas Rushworth teaches use of only one;
modifying Hadrup and Rushworth with Ruella and Kim fails to suggest the solution to the problem solved by the present claims in that they do not suggest the claimed solution;
a skilled artisan would not have been motivated to substitute one of the CARs of Ruella with the anti-FITC CAR of Kim because Kim did not recognize the problem solved by Ruella let alone the present claims, in that Ruella was addressing the issue of antigen loss whereas Kim was addressing the issue of off-target effects, and the present claims address the issue of effector cell persistence;
Ruella does not provide motivation to substitute one of its CARs with the FITC-CAR of Kim since cancer cells do not naturally express FITC;
Kim does not guide the skilled artisan to a system having direct binding between a small molecule hapten covalently attached to the plasma membrane of an H-APC and an anti-hapten CAR of an effector cell, and that such a redesign substantially changes the principle of operation of Kim;
Examiner has mischaracterized the teachings of Kozer in that Kozer teaches ConA-FITC, which interacts with glycoproteins on the cell surface rather than integrating into the plasma membrane;
However, this is not agreed.
In response to applicant’s arguments against the references individually, it is noted that 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). One cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). Further, the examiner recognizes that obviousness may be established by combining or modifying the teachings of the prior art to produce the claimed invention where there is some teaching, suggestion, or motivation to do so found either in the references themselves or in the knowledge generally available to one of ordinary skill in the art. See In re Fine, 837 F.2d 1071, 5 USPQ2d 1596 (Fed. Cir. 1988), In re Jones, 958 F.2d 347, 21 USPQ2d 1941 (Fed. Cir. 1992), and KSR International Co. v. Teleflex, Inc., 550 U.S. 398, 82 USPQ2d 1385 (2007). In addition, it must be recognized that any judgment on obviousness is in a sense necessarily a reconstruction based upon hindsight reasoning. But so long as it takes into account only knowledge which was within the level of ordinary skill at the time the claimed invention was made, and does not include knowledge gleaned only from the applicant's disclosure, such a reconstruction is proper. See In re McLaughlin, 443 F.2d 1392, 170 USPQ 209 (CCPA 1971).
Specifically, regarding argument 1)a., that Kim teaches indirect binding between an anti-fluorescein CAR T cell and a protein antigen via a macromolecular bridging molecule, such that Kim does not teach or suggest that the effector cell directly binds to a hapten as required by the present claims, note that Kim was relied on for teaching an anti-FITC CAR. Kim teaches direct binding between the anti-FITC CAR and the fluorescein hapten, such that the effector cell directly binds to the hapten via the CAR scFv [Figure 1].
Regarding argument 1)b., McEnaney was cited for teaching the attachment of haptens to label target cells to promote an interaction between the target cell and antibodies which bind to the hapten molecule [column 4 paragraph 1]. Although the antibodies taught by McEnaney were not part of CAR complex embedded in an effector cell, McEnaney teaches the use of the hapten to recruit an antibody to the surface of the target cell. McEnaney was additionally cited for teaching that fluorescein is an especially useful hapten because anti-fluorescein antibodies are easily induced and its photophysical properties provide a convenient handle for binding and imaging studies [column 6 paragraph 2].
Regarding argument 1)c., that Kozer only teaches a conjugate that can bind to sugars on a cell, note that while Kozer teaches the ConA-FITC construct, Kozer was cited for the additional teaching of an FITC-DHPE construct, e.g., (N-(fluorescein-5-thiocarbamoyl)-1,2-dihexadecanoyl-sn-glycero-3-phospho-ethanolamine), as a FRET donor-tagged phospholipid for use as a zero vertical separation control, such that the FITC-DHPE is embedded int the outer plasma membrane of the cell [column 6 ¶ 3, column 7 ¶ 1].
Therefore, Kim, McEnaney, and Kozer together teach an anti-FITC CAR in an effector cell, wherein the anti-FITC CAR binds directly to fluorescein, the labeling of target cells with an FITC hapten to recruit antibody binding to the target cell, and the embedding of an FITC hapten into the outer plasma membrane of cell via a covalent linkage to a phospholipid. Accordingly, the combined teachings of Kim, McEnaney, and Kozer teach the limitations to modify the system and methods of Ruella to replace one of the CARs with and/or to add an additional CAR which is an anti-FITC CAR which binds to an H-APC with FITC covalently attached to the surface of the H-APC.
As discussed in the prior actions, Kim, McEnaney, and Kozer additionally teach the motivations for using each of the components.
Firstly, Ruella teaches CD19-directed immunotherapies are changing the paradigm of treatment of relapsed refractory B-ALL, but that leukemia cells are able to develop escape mechanisms which lead to resistance and relapse: the two main patterns of relapse being i) early loss of CART19 through failure of persistence of CART19 cells and ii) occurrence of a CD19-negative leukemia [column 16 ¶ 2]. Therefore, Ruella teaches the need to combat the failure of persistence of CART19 cells following administration of the CART19 cells to a patient. Ruella also teaches that a dual CAR provides increased anti-tumor activity when targeted to cells comprising both CAR ligands [column 16 ¶ 1], and that dual CAR-expressing CAR-T cells have enhanced early activation and augmented in vivo expansion relative to singly-activated CAR-T cells [column 18 ¶ 1]. Given the teaching of Ruella that the other main category of relapsed leukemia involves a loss of the CD19 CAR-T cells early in treatment, and the teaching that dual CAR-T cells are activated and expanded to a larger extent than singly activated CAR-T cells early on, an ordinarily skilled artisan would have been motivated to design a dual CAR-T cells to target patients which have reduced or lost CD19 CAR-T cells such that the CAR-T cell population can be better expanded and maintained via secondary stimulation by the second CAR construct.
Additionally, Rushworth was cited for teaching a universal artificial APC which can be used for expansion of CAR-T cells with a variety of specificities, thereby removing the need to design a new aAPC for each TAA CAR target. Given the teachings of Rushworth to use a universal artificial APC to stimulate CAR-T cells, an ordinarily skilled artisan would have been motivated to design the second CAR construct to target a universal aAPC, which can be incubated with the CAR-T cells to stimulate and expand the CAR-T cell ex vivo prior to administration to the patient and/or in vivo following a loss/reduction of CAR-T cells within the patient.
Kim was cited for teaching the motivation to use a CAR T cell comprising a CAR which binds to a hapten, such as fluorescein, to allow greater control of the CAR T cell activity following administration to a patient. McEnaney was cited for teaching the motivation to utilize a fluorescein hapten to covalently label the extracellular surface of cells to induce an antibody/ ligand binding interaction with a target cell. Kozer provides the teachings for how to facilitate the FITC binding to the cell surface by integrating the FITC-DHPE into the plasma membrane of a cell to label the cell such that the fluorescein molecules are presented on the surface of the cell.
Combining the teachings and motivations of Ruella and Rushworth with the teachings and motivations of Kim, McEnaney, and Kozer, an ordinarily skilled artisan would modify the system and method of Ruella to arrive at a bispecific CAR-T cell comprising at least one tumor-specific CAR and a FITC hapten-specific CAR and a hapten antigen presenting cell (H-APC), wherein the H-APC comprises FITC covalently attached to a phospholipid integrated into the plasma membrane of the H-APC, and wherein the H-APC serves to stimulate the bispecific CAR effector cell to increase expansion of the CAR effector cells.
Regarding argument 2)a., that there is no motivation in Hadrup and Rushworth, alone or in combination, what would lead a skilled artisan to the claimed system where the effector cell is activated through two antigens since the combination of Hadrup and Rushworth causes the art to become inoperable or destroy its intended function, in that the combination would require substantial reconstruction and redesign and change the basic principles under which the reference teachings were designed to operate since Hadrup teaches use of multiple stimulatory molecules whereas Rushworth teaches use of only one; note that Hadrup and Rushworth were not cited for teaching an effector cell which is activated through two antigens. The base reference, Ruella, already specifically teaches an effector cell which is activated through two antigens, and as such, activation through two antigens is not a modification of the base reference. Additionally, Ruella teaches that dual CAR-expressing CAR-T cells have enhanced early activation and augmented in vivo expansion relative to singly-activated CAR-T cells [column 18 ¶ 1].
Regarding argument 2)b., that modifying Hadrup and Rushworth with Ruella and Kim fails to suggest the solution to the problem solved by the present claims in that they do not suggest the claimed solution, note that the rejection of record is not a modification of Hadrup and Rushworth with Ruella and Kim, but a modification of Ruella with Imai, Bio-Rad, Kim, Hadrup, Dissanayake, McEnaney, Kozer, and Rushworth. Additionally, as discussed above, it is noted that the test for obviousness is 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. As such, each reference is not required to have proposed the same solution as claimed in the instant claims, but that an ordinarily skilled artisan would have arrived at the claimed solution given the teachings, suggestions, and motivations taught in the art.
As described above, Ruella teaches the problem to be solved: that following CAR19 T cells administration, leukemia cells are able to develop escape mechanisms which lead to resistance and relapse: the two main patterns of relapse being i) early loss of CART19 through failure of persistence of CART19 cells and ii) occurrence of a CD19-negative leukemia [column 16 ¶ 2]. Further, Ruella teaches that dual CAR-expressing CAR-T cells have enhanced early activation and augmented in vivo expansion relative to singly-activated CAR-T cells [column 18 ¶ 1].
Rushworth teaches that universal artificial antigen presenting cells (UaAPCs) allow ex vivo numeric expansion of CAR T cells for sustained proliferation independent of CAR specificity [abstract]. Rushworth also teaches that the UaAPCs avoids technical issues and costs associated with deploying clinical-grade aAPC for each tumor associated antigen (TAA) targeted by a given CAR and enables 1 aAPC to numerically expand all CAR T cells containing the IgG4 domain, thereby simplifying expansion, testing, and clinical translation of CAR T cells of any specificity [abstract]. As such, an ordinarily skilled artisan would have been motivated to use a universal aAPC to stimulate expansion of a CAR T cell to avoid technical issues and costs associated with deploying clinical-grade aAPC for each TAA and to simplify expansion, testing, and clinical translation of CAR T cells of independent of tumor antigen specificity.
As described in 1) above, Kim was cited for teaching the motivation to use a CAR T cell comprising a CAR which binds to a hapten, such as fluorescein, to allow greater control of the CAR T cell activity following administration to a patient. McEnaney was cited for teaching the motivation to utilize a fluorescein hapten to covalently label the extracellular surface of cells to induce an antibody/ ligand binding interaction with a target cell, such as a monocyte. Kozer provides the teachings for how to facilitate the FITC binding to the cell surface by integrating the FITC-DHPE into the plasma membrane of a cell to label the cell such that the fluorescein molecules are presented on the surface of the cell.
Combining the teachings and motivations of Ruella and Rushworth with the teachings and motivations of Kim, McEnaney, and Kozer, an ordinarily skilled artisan would modify the system and method of Ruella to arrive at a bispecific CAR-T cell comprising at least one tumor-specific CAR and a FITC hapten-specific CAR and a hapten antigen presenting cell (H-APC), wherein the H-APC comprises FITC covalently attached to a phospholipid integrated into the plasma membrane of the H-APC, and wherein the H-APC serves to stimulate the bispecific CAR effector cell to increase expansion of the CAR effector cells in a TAA independent manner.
Regarding 2)b., that a skilled artisan would not have been motivated to substitute one of the CARs of Ruella with the anti-FITC CAR of Kim because Kim did not recognize the problem solved by Ruella let alone the present claims, in that Ruella was addressing the issue of antigen loss whereas Kim was addressing the issue of off-target effects, and the present claims address the issue of effector cell persistence, note that Ruella was also addressing the issue of loss of CAR effector cells over time. Further, Kim was not relied on for the motivation to use a TAA-independent artificial APC, which was taught by Rushworth. Kim was relied on for providing the teachings and motivation for an alternative CAR which can be used to bind a FITC hapten for additional control of the CAR T cell activity following administration of the CAR T cell to a patient, including the use of hapten-specific administration following the initial CAR T cell administration to promote persistence of the CAR T cell within the patient.
Kim teaches monitoring the peripheral blood T cell count in subjects following administration of the CAR-T cells and the fluorescein-antiCD19 switch, wherein the amount of the effector CAR-T cells in the subject decline over time following administration of the effector T cell to the subject [0510, 0521, Figure 66B]. Kim also teaches that the in vivo CAR-T cell activity and expansion can be controlled by hapten switch dose [0510], and to compare CAR effector cell proliferation following administration of a dose of switch and continuing administering additional doses after comparing, if needed [0425]. Kim also teaches that persistence of CAR-T cells is critical to enable redosing strategies in the case of relapse, and that persistence may be promoted through rest phases in which switch dosing is withheld to prevent exhaustion related to persistent T cell signaling [0425]. Therefore, Kim teaches the motivation to assess the persistence of CAR-T effector cells in a subject after administration of the effector cells to the subject, wherein additional doses of stimulant can be administered to promote persistence of the effector cells. As such, Kim did recognize the problem of a lack of persistence of the CAR T cells in a patient and addressed way to address the problem with their system of using an FITC-specific CAR T cell administration followed by subsequence administrations of the FITC-comprising switch to stimulate and promote persistence of the CAR T effector cells.
Regarding argument 2)d., that Ruella does not provide motivation to substitute one of its CARs with the FITC-CAR of Kim since cancer cells do not naturally express FITC, note that Ruella was note relied on for teaching the motivation to substitute a CAR for the CAR of Kim. As discussed above, Rushworth provides the motivation for using a TAA-independent aAPC, and Kim provides the motivation for a FITC-CAR, wherein administration of an FITC stimulus promotes persistence of the CAR within the patient after administration.
Regarding argument 2)e., that Kim does not guide the skilled artisan to a system having direct binding between a small molecule hapten covalently attached to the plasma membrane of an H-APC and an anti-hapten CAR of an effector cell, and that such a redesign substantially changes the principle of operation of Kim. Note that, as described above, Kim was not relied on for teaching an aAPC, but that an FITC-CAR can be administered to a subject such that the FITC-CAR directs the CAR T cell to interact with a target cell, wherein following administration, the activity and persistence of the FITC-CAR within the subject can by modulated by administration of a FITC hapten-comprising conjugate which allows for control of the CAR T cells following administration to the subject. Rushworth provides teachings and motivations for using a TAA-independent aAPC, and McEnaney and Kozer teach to label the surface of target cells with FITC to recruit antibody interactions with the target cell.
Regarding argument 2)f., that Examiner has mischaracterized the teachings of Kozer in that Kozer teaches ConA-FITC, which interacts with glycoproteins on the cell surface rather than integrating into the plasma membrane; as discussed above, although Kozer teaches the ConA-FITC construct, Kozer was cited for the additional teaching of an FITC-DHPE construct, e.g., (N-(fluorescein-5-thiocarbamoyl)-1,2-dihexadecanoyl-sn-glycero-3-phospho-ethanolamine), as a FRET donor-tagged phospholipid for use as a zero vertical separation control, such that the FITC-DHPE is embedded into the outer plasma membrane of the cell [column 6 ¶ 3, column 7 ¶ 1]. As such, Kozer teaches the covalent attachment of a FITC to a phospholipid integrated into the membrane.
*The following new rejection is necessitated by Applicant’s amendments to the claims.
New claims 144-145 and 147 are newly rejected under 35 U.S.C. 103 as being unpatentable over Ruella et al. [2016, J. Clin. Invest., Vol. 126(10), 3814-3826, cited in a prior action]; in view of Imai et al. [2004, Leukemia, Vol. 18, 676-684, cited in a prior action]; Bio-Rad [2016, The T Cell Marker, CD3 Antigen and Antibodies, retrieved on 4 May 2024 from the Internet: <URL: https://www.bio-rad-antibodies.com/static/2016/innate/the-t-cell-marker-cd3-antigen-and-antibodies.pdf>, cited in a prior action]; Kim et al. [US20180100026A1, published 12 April 2018, cited in a prior action]; Hadrup et al. [WO2018115146A1, published 28 June 2018, cited in a prior action]; Dissanayake et al. [2014, PLoS ONE, Vol 9(3), 1-10, cited in a prior action]; McEnaney et al. [2012, ACS Chem. Biol., Vol. 7, 1139-1151, cited in a prior action]; Kozer et al. [2011, Physical Biology, Vol. 8, 066002, 1-13, cited in a prior action]; and Rushworth et al. [2014, Journal of Immunotherapy, Vol. 37(4), 204-213, cited in a prior action]; as applied to claims 115-120, 122, 124, 128, 133-135, 138-141, and 143, and newly applied to new claim 146 above; and further in view of Itagaki et al. [2015, Colloids and Surfaces B: Biointerfaces, 135, 765-773]; Blitterswijk et al. [2013, Biochimica et Biophysica Acta, 1831, 663-674]; and Okuda-Shingawa et al. [2017, ACS Omega, 2, 8156-8166].
As discussed above, Ruella, Imai, Bio-Rad, Kim, Hadrup, Dissanayake, McEnaney, Kozer, and Rushworth provide the teachings and motivations for the limitations of independent claim 115, upon which claims 144-145 depend.
However, the combined teachings of Ruella, Imai, Bio-Rad, Kim, Hadrup, Dissanayake, McEnaney, Kozer, and Rushworth do not teach wherein the phospholipid is linked to the FITC hapten via a polyethylene glycol (PEG) spacer, wherein the PEG spacer has a length of 1 to 16 subunits.
Regarding claim 144, Itagaki teaches FITC-PEG-phospholipids which spontaneously anchored to the cell membrane within 15 minutes without loss of cell viability [abstract, column 10 ¶ 1, Scheme 1], and that the cell surface modification allows for control of biological reactions occurring at cell surface [column 16 ¶ 4].
Therefore, given the teaching of Itagaki that FITC-PEG-phospholipids spontaneously and rapidly anchor to the cell membrane without loss of cell viability and that the cell surface modification with the FITC-PEG-phospholipids allows for control of biological reactions occurring at cell surface, an ordinarily skilled artisan at the time of filing the instant application would have been motivated to use a fluorescein-PEG-phospholipid to label a cell surface through incorporation of the conjugated phospholipid into the cell membrane.
Regarding claim 145, Blitterswijk teaches a phospholipid, miltefosine, which has the phospholipid structure as depicted in Formula (I), (e.g., the quaternary amine through the alkyne group comprising both the polar head moiety and the hydrophobic tail moiety) [Figure 1]. Blitterswijk further teaches that the miltefosine is a synthetic alkylphospholipid (ALP) which easily inserts in the outer leaflet of the plasma membrane, resists catabolic degradation, and accumulates in the cell [abstract]. Therefore, an ordinarily skilled artisan at the time of filing the instant application would have been motivated to use a miltefosine phospholipid for anchoring a conjugated moiety (e.g., a fluorescein hapten) to the outer cell membrane of a target cell.
Okuda-Shinagawa teaches 5-carboxyfluorescein (FAM)-PEG6 conjugation to cell penetrating peptides, such that the PEG serves as a linker/spacer between the FAM and the peptide, wherein the FAM-PEG6 structure matches the structure of the fluorescein-PEG depicted in Formula (I) [column 3 ¶ 2, Figure 1]. Okuda-Shinagawa also teaches that the motivation for using the fluorophore FAM was that 5-FAM and 6-FAM both display fluorescent properties with absorption at 492 nm and emission at 518 and 515, respectively, and the mixture of 5-FAM + 6-FAM (e.g., FAM) is probably the most popular fluorescent dye used for labeling and imaging applications involving peptides, proteins, and oligonucleotides such that they are widely used to understand protein/peptide interactions with biological membranes [column 4 ¶ 3- column 5 ¶ 1].
Okuda-Shinagawa further teaches that the PEG6 spacer minimizes steric hindrance between the bulky fluorescent cargo and the peptide, helps to preserve the photo-physical properties of the fluorophore, increases water solubility of the conjugates, and is biologically inert [column 5 ¶ 5-column 6 ¶ 1]. Additionally, Okuda-Shinagawa teaches that low molecular mass PEG6 display low cytotoxicity [column 6 ¶ 1].
Therefore, an ordinarily skilled artisan at the time of filing the instant application would have been motivated to use a PEG6 spacer between a fluorescein moiety and another moiety (e.g., a phospholipid moiety) to minimizes steric hindrance between the bulky fluorescent cargo and the other moiety, preserve the photo-physical properties of the fluorescein, and increase water solubility of the conjugate without introducing any cellular toxicity.
Regarding claim 147, as discussed above, Ruella in view of Imai, Bio-Rad, Kim, Hadrup, Dissanayake, McEnaney, Kozer, and Rushworth teach a method of treating , inhibiting, or ameliorating a cancer in a subject, comprising a) administering an effector cell to the subject, wherein the effector cell comprises a first CAR specific for a tumor antigen of the cancer, and a second CAR specific for a fluorescein hapten; b) measuring a reduction in an amount of the effector cell in the subject over time; and c) administering a fluorescein hapten antigen presenting cell (H-APC) to the subject, wherein the H-APC comprises a compound comprising the hapten and a phospholipid, wherein the phospholipid is integrated into the plasma membrane of the H-APC, wherein step (c) is performed after step (b). Additionally, as discussed above, Itagaki, Blitterswijk, and Okuda-Shinagawa provide the teachings and motivations for wherein the hapten is covalently linked to the phospholipid via a PEG spacer, wherein the PEG spacer has a length of 6 ethylene glycol subunits.
Given the motivation taught by Itagaki to use a fluorescein-PEG-phospholipid to label a cell surface through incorporation of the conjugated phospholipid into the cell membrane; the teachings of Blitterswijk that the phospholipid miltefosine easily inserts in the outer leaflet of the plasma membrane, resists catabolic degradation, and accumulates in the cell; the teachings of Okuda-Shinagawa that a PEG6 spacer minimizes steric hindrance between a bulky fluorescent cargo and other moieties in a conjugate, helps to preserve the photo-physical properties of the fluorophore, increases water solubility of the conjugates, and is biologically inert with low toxicity; the further teachings of Okuda-Shinagawa that FAM is a popular fluorescent dye used to understand interactions with biological membranes; it would have been prima facie obvious to further modify the system and methods of Ruella in view of Imai, Bio-Rad, Kim, Hadrup, Dissanayake, McEnaney, Kozer, and Rushworth, as described above, such that the fluorescein hapten is linked to the phospholipid via a PEG spacer, wherein the PEG spacer has a length of 6 ethylene glycol subunits, and wherein the phospholipid is miltefosine according to formula (I) with a reasonable expectation of success.
Conclusion
No claim is allowed.
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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DR. KATIE L. PENNINGTON
Examiner
Art Unit 1634
/KATIE L PENNINGTON/Examiner, Art Unit 1634
Dr. A.M.S. Wehbé
/ANNE MARIE S WEHBE/Primary Examiner, Art Unit 1634