DETAILED ACTION
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
The claim listing filed on April 22, 2023 is pending.
Claim 1 is independent.
Claims 1-13 are pending and currently under consideration.
Nucleotide and/or Amino Acid Sequence Disclosures
The incorporation by reference paragraph required by 37 CFR 1.834(c)(1), 1.835(a)(2), or 1.835(b)(2) is missing. The Applicant must provide a substitute specification in compliance with 37 CFR 1.52, 1.121(b)(3), and 1.125 inserting the required incorporation by reference paragraph, consisting of:
A copy of the previously-submitted specification, with deletions shown with strikethrough or brackets and insertions shown with underlining (marked-up version);
A copy of the amended specification without markings (clean version); and
A statement that the substitute specification contains no new matter.
Priority
The present application is a 35 U.S.C. 371 national stage filing of International Application No. PCT/EP2021/080310 filed on 11/02/2021. This application is claiming foreign priority to European Patent Office (EPO) Application No. EP20205657.8 filed on 11/04/2020.
A certified copy of PCT/EP2021/080310 (EP20205657.8) was filed on 04/22/2023.
Claims 1-13 are being examined with an effective filing date of November 4, 2020.
Claim Interpretation
As is noted below, claims 10, 12, and 13 are rejected under U.S.C. 101 and 122(b) for being drawn to “Use” claims. However, for the purpose of applying prior art only, the claims are being interpreted as methods of treating cancer comprising administering the instantly claimed population of engineered cells expressing the chimeric antigen receptor (CAR).
Claim Objections
Claims 4-9 and 11 are objected to under 37 CFR 1.75(c) as being in improper form because a multiple dependent claim should refer to other claims in the alternative only and cannot depend from any other multiple dependent claim. See MPEP § 608.01(n).
For example, claim 4 recites “…according to at least of the claims 1 to 3…” in line 1. This phrase does not refer to claims 1-3 in alternative form and it depends on another multiple dependent claim (claim 3). The remaining claims are objected to for similar reasons.
Amending the claims so that multiple dependent claims are not dependent on other multiple dependent claims and so that multiple dependent claims refer to dependent claims in the alternative would obviate this part of the rejection.
For the purpose of examination, the claims are being read as dependent on claim 1.
Claims 2-8 are objected to because of the following informalities: Claims 2-7 recite the phrase “A chimeric antigen receptor (CAR)” but refer to the CAR recited in the base claim (claim 1). The term “A” is generally used at the beginning of an independent claim which is drawn to a different invention then a preceding claim. However, since claims 2-7 refer to the CAR initially recited in claim 1, the phrase “A chimeric antigen receptor (CAR)” should be replaced with the phrase “The chimeric antigen receptor (CAR).”
Claim 4 also recites “an transmembrane domain” which should be “a transmembrane domain.”
Claim 8 also recites the phrase “Method of binding…” but should recite “A method of binding…”
Appropriate correction is required.
Claim Rejections - 35 USC § 101
35 U.S.C. 101 reads as follows:
Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title.
Claims 10, 12, and 13 are rejected under 35 U.S.C. 101 because the claimed invention is directed to non-statutory subject matter. The claims do not fall within at least one of the four categories of patent eligible subject matter. "Use" claims that do not purport to claim a process, machine, manufacture, or composition of matter fail to comply with 35 U.S.C. 101. See MPEP 2173.05(q).
This applies to the instant case where claims 10, 12, and 13 are drawn to the “use” of a product (a population of engineered cells or a pharmaceutical composition) for the treatment of human cancer but fail to claim a process, machine, manufacture, or composition of matter.
Claim Rejections - 35 USC § 112
Indefinite Language
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.
Claims 2-7, 10, 12, and 13 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 applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 2 recites the limitation “in that the CAR comprises an antigen binding domain specific for MSLN in combination with at least two antigen binding domains specific for at least two different antigens selected from the group consisting of CLA, CD66c, TSPAN8 and CD318” in lines 1-4.
Claim 3 recites the limitations “in that the CAR comprises an antigen binding domain, a transmembrane domain and an intracellular signaling domain” and “one antigen binding domain specific for an antigen selected from the group consisting of CLA, CD66c, TSPAN8 and CD318” in lines 1-3 and 4-6, respectively.
Claim 4 recites the limitation “in that the CAR comprises an antigen binding domain, an transmembrane domain and an intracellular signaling domain and comprising an antigen binding domain specific for MSLN in combination with one or more antigen binding domains specific for an antigen selected from the group consisting of CLA, CD66c, TSPAN8 and CD318” in lines 2-5.
Claim 6 recites the limitation “in that in that the CAR comprises an anti-tag binding region which can bind to a tag which is coupled to an antigen binding domain specific for one or more antigens selected from the group consisting of MSLN, CLA, CD66c, TSPAN8 and CD318” in lines 2-5.
Claim 7 recites the limitation “in that the CAR comprises an anti-tag binding region which can bind to a tag which is coupled to an antigen binding domain specific for MSLN in combination with at least two antigen binding domains specific for at least two different antigens selected from the group consisting of CLA, CD66c, TSPAN8 and CD318” in lines 2-5.
Claims 2-4, 6, and 7 are dependent on claim 1, which recites that the CAR is comprised of a MSLN binding domain and a CLA, CD66c, TSPAN8 and/or CD318 binding domain, but does not recite any additional structural elements, such as additional antigen binding domains, a transmembrane domain, an intracellular signaling domain, or anti-tag binding regions.
It is unclear if the additional structural elements of claims 2-4, 6, and 7 are in addition to or in place of the MSLN and CLA, CD66c, TSPAN8 or CD318 binding domains. Thus, there is insufficient antecedent basis for these limitations in the claims.
If claims 2-4, 6, and 7 are meant to depend on claim 1, amending the claims to recite that the CAR “further comprises” these additional elements would obviate this part of the rejection. If these additional elements are meant to be in place of the binding regions recited in claim 1, amending the claims to be in independent form would obviate this part of the rejection.
Claim 4 also recites the limitation “conjugated to the same or a different transmembrane domain and/or intracellular signaling domain” in lines 6 and 7. However, claims 3 and 4 recite that there is only one transmembrane domain. Thus, there is insufficient antecedent basis for this limitation in the claim 4 because it encompasses more than one transmembrane domain in the CAR.
Claim 5 recites the limitations “the transmembrane domain” and “the intracellular signaling domain” in lines 2 and 3, respectively. However, claim 5 is dependent on claims 1 and 2 (in addition to claims 3 and 4) which do not recite “a transmembrane domain” or “an intracellular signaling domain.” Thus, there is insufficient antecedent basis for these limitations in the claim 5.
Claims 10, 12, and 13 recite the “Use of the…” in line 1. Attempts to claim a process without setting forth any steps involved in the process generally raises an issue of indefiniteness under 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph. See MPEP 2173.05(q).
This applies to the instant case where claims 10, 12, and 13 are drawn to the “use” of a product (a population of engineered cells or a pharmaceutical composition) for the treatment of human cancer but fail to set forth any steps involved in the process.
Written Description
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 1-13 are 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 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 applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
The instant claims are drawn to a chimeric antigen receptor (CAR), comprising an antigen binding domain specific for MSLN in combination with one or more antigen binding domains specific for an antigen selected from the group consisting of CLA, CD66c, TSPAN8 and CD318; a population of engineered cells expressing the CAR; and a pharmaceutical composition comprising the population of engineered cells expressing the CAR.
The Applicant has not disclosed any specific CARs that combine an anti-MSLN binding domain with one or more antigen binding domains targeting CLA, CD66c, TSPAN8, or CD318. It is noted that the Applicant has disclosed two general examples of multispecific CAR variant designs, a split CAR and a tandem CAR, which comprise multiple antigen binding domains which target different antigens (e.g. see Figure 2). In light of Figure 2, one would assume that the CDRs or VH and VL domains of an antibody or antigen binding fragment thereof that binds a desired antigen could be used in these antigen binding domains and be combined to make a multispecific CAR.
To this end, the Applicant has disclosed four specific anti-MSLN scFv antigen binding domains (SEQ ID NOs: 33, 34, 37, and 38) (e.g. see sequences on pages 26 and 27). These scFv comprise two different amino acid sequences that are arranged in two alternative VH and VL configurations (i.e. VH-linker-VL or VL-linker-VH) (e.g. see sequences on pages 26 and 27). The Applicant has also disclosed eight scFv antigen binding domains (two each) that target CLA (SEQ ID NOs: 17 and 18), CD66c (SEQ ID NOs: 25 and 26), TSPAN8 (SEQ ID NOs: 31 and 32), or CD318 (SEQ ID NOs: 29 and 30). These scFv are also arranged in two alternative VH and VL configurations (i.e. VH-linker-VL or VL-linker-VH) (e.g. see sequences on pages 26 and 27). All of the scFvs comprise the corresponding VH and VL amino acid sequences recited on pages 20-22, 26, and 27. The CDRs of the anti-CLA, CD66c, TSPAN8, and CD318 VH and VL amino acid sequences are underlined on pages 20-22. The Applicant has also disclosed antibodies targeting CD66c (clone REA414), CD318 (clone REA194), TSPAN8 (REA443), and MSLN (clone REA1057) (e.g. see page 28).
It is noted that the Applicant has not disclosed any examples that apply a CAR targeting MSLN, CLA, CD66c, TSPAN8, and/or CD318 in a method of binding a cancer cell. The only example that is disclosed is an in vitro experiment that employs an adapter CAR (Ad CAR) which specifically binds an adapter (LC-LC-Biotin) that is expressed on antibodies that specifically bind MSLN, CD66c, TSPAN8, and CD318 (e.g. see pages 28 and 29). This creates a kind of scaffold where the target specific antibodies are sandwiched between the CAR T cell and a cell expressing the antigen. All of the targeted binders exhibited specific killing capacity. The Applicant concluded that the binders according to the invention show effective and specific killing of the target cells on three independent cell lines for four different targets and combinations thereof (e.g. see pages 28 and 29). However, it is noted that “binders according to the invention” of claims 1-5 and 8-13, in part, where not used in this example since the “binders according to the invention” are drawn to CARs that specifically target these antigens, not CARs that bind antibodies that target these antigens. Thus, this example is not commensurate in scope with claims 1-5 and 8-13, in part.
When given the broadest reasonable interpretation in light of specification, the multi-specific anti-MSLN CARs of the instant invention are defined broadly to be any CAR molecule that comprises an anti-MSLN antigen binding domain and one or more antigen binding domains specific for CLA, CD66c, TSPAN8, or CD318.
It is noted that the broadest claim (claim 1) does not indicate any specific structure for the genus of the multi-specific anti-MSLN CARs as claimed.
None of the dependent claims rectify this deficiency.
The guidelines for the Examination of Patent Applications Under the 35 U.S.C. 112, § 1 "Written Description" Requirement make clear that if a claimed genus does not show actual reduction to practice for a representative number of species, then the Requirement may be alternatively met by reduction to drawings, or by disclosure of relevant, identifying characteristics, i.e., structure or other physical and or chemical properties, by functional characteristics coupled with a known or disclosed correlation between function and structure, or by a combination of such identifying characteristics, sufficient to show the applicant was in possession of the genus (Federal Register, Vol. 66, No. 4, pages 1099-1111, January 5, 2001, see especially page 1106 column 3). In The Regents of the University of California v. Eli Lilly (43 USPQ2d 1398-1412) 19 F. 3d 1559, the court held that disclosure of a single member of a genus (rat insulin) did not provide adequate written support for the claimed genus (all mammalian insulins). In this same case, the court also noted:
“A definition by function, as we have previously indicated, does not suffice to define the genus because it is only an indication of what the gene does, rather than what it is. See Fiers, 984 F.2d at 1169-71, 25 USPQ2d at 1605-06 (discussing Amgen). It is only a definition of a useful result rather than a definition of what achieves that result. Many such genes may achieve that result. The description requirement of the patent statute requires a description of an invention, not an indication of a result that one might achieve if one made that invention. See In re Wilder, 736 F.2d 1516, 1521, 222 USPQ 369, 372-73 (Fed. Cir. 1984) (affirming rejection because the specification does “little more than outlin[e] goals appellants hope the claimed invention achieves and the problems the invention will hopefully ameliorate.”). Accordingly, naming a type of material generally known to exist, in the absence of knowledge as to what that material consists of, is not a description of that material.”
It is well known that antigen binding domains of CARs fall in three general categories, either single chain variable fragments (scFvs) derived from antibodies, Fab’s selected from libraries, or natural ligands that engage their cognate receptor (e.g. see Sadelain et al. Cancer Discov. 2013;3(4):388–398, page 389, left column, second paragraph under “CAR TARGETING”). Successful examples in each of these categories have been reported. scFvs derived from murine immunoglobulins are commonly used, as they are easily derived from well-characterized monoclonal antibodies. They, however, may prove to be more immunogenic than Fab’s derived from human libraries or invariant human ligands (e.g. see Sadelain et al. Cancer Discov. 2013;3(4):388–398, page 389, left column, second paragraph under “CAR TARGETING”).
Regarding CARs comprising antibody-derived antigen binding domains, artisans are well aware that knowledge of a given antigen (for instance MSLN, CLA, CD66c, TSPAN8, and CD318) provides no information concerning the sequence/structure of antibodies that bind the given antigen. For example, Edwards et al. (J. Mol. Biol., 2003, 334:103-118) teach that over 1,000 different antibodies to a single protein can be generated, all with different sequences spanning almost the entire heavy and light chain germline repertoire (42/49 functional heavy chain germlines and 33 of 70 V-lambda and V-kappa light chain germlines, and with extensive diversity in the HCDR3 region sequences (that are generated by VDJ germline segment recombination) as well, see entire document).
As such, it does not seem possible to predict the sequence/structure of an antibody that binds a given antigen, as there does not appear to be any common or core structure present within all antibodies that gives rise to the function of antigen binding. Further, given data, such as that of Edwards et al., indicating the diversity of sequences in a population of antibodies that bind to a given antigen, no number of species appears to reasonably representative of the breadth of the genus of antibodies that bind the given antigen.
It should be pointed out that it is well established in the art that the formation of an intact antigen-binding site requires the association of the complete heavy and light chain variable regions of a given antibody, each of which consists of three different complementarity determining regions, CDR1, 2 and 3, which provide the majority of the contact residues for the binding of the antibody to its target epitope. The amino acid sequences and conformations of each of the heavy and light chain CDRs are critical in maintaining the antigen binding specificity and affinity which is characteristic of the parent immunoglobulin (Janeway Jr et al., Immunology, 3rd Edition, 1997 Garland Publishing Inc., pages 3:1-3:11.see entire selection).
Thus, based upon the prior art, skilled artisans would reasonably understand that it is the structure of the CDRs within an antibody which gives rise to the functional property of antigen binding, the epitope to which said CDRs bind is an inherent property which appears to necessarily be present due to conservation of critical structural elements, namely the CDR sequences themselves.
This applies to the instant invention which is drawn to a genus of multi-specific anti-MSLN CARs that encompasses those that comprise antigen binding domains derived from antibodies, namely an scFv comprising the CDRS or VH and VL domains of a parent antibody.
As noted above, the specification does not disclose any specific CARs that combine an anti-MSLN binding domain with an antigen binding domain targeting CLA, CD66c, TSPAN8, or CD318. However, the Applicant has disclosed four specific anti-MSLN scFv antigen binding domains, eight scFv antigen binding domains (two each) that target CLA, CD66c, TSPAN8, or CD318, and four antibodies that target MSLN, CD66c, TSPAN8, or CD318, which can theoretically be combined into a multispecific CAR according to Figure 2.
However, such a disclosure does not serve to provide sufficient written description of the claimed genus of multi-specific anti-MSLN CARs. Further, the disclosure does not identify any specific structural features or combination of features which give rise to the function of binding to MSLN and CLA, CD66c, TSPAN8, or CD318. Additionally, there does not appear to be any reasonable shared structure present in the genus of recited multi-specific anti-MSLN CARs which gives rise to their functional activity. Ultimately, identifying an CAR simply on the basis of what it binds rather than by identifying the sequence/structure, namely the CDRs, of the CAR in question is generally insufficient to provide written description of the CAR in question.
There is insufficient written description for the breadth multi-specific anti-MSLN CARs as currently claimed, which are distinct and diverse and do not share a common structure that contributes to a common ability to bind to MSLN and CLA, CD66c, TSPAN8, or CD318.
Therefore, in view of the breadth of the claims and the limited disclosure, artisans would reasonably conclude that applicant was not in possession of the full breadth of multi-specific anti-MSLN CARs encompassed by the claims at the time the instant application was filed.
Enablement
Claims 1, 2, and 5-13 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, because the specification, while being enabling for a chimeric antigen receptor (CAR) that comprises an antigen binding domain, a transmembrane domain comprising one sequence of the transmembrane domains of 4-1BB, CD8, or CD28, and an intracellular signaling domain comprising a sequence of the intracellular signaling domains of CD3zeta and CD28 and/or CD137; does not reasonably provide enablement for a CAR that (1) does not comprise a transmembrane domain or an intracellular signaling domain; (2) comprises more than one sequence of the transmembrane domains of 4-1BB, CD8, and/or CD28; or (3) comprises a sequence of the intracellular signaling domains of one or more of CD28, CD137, and CD3zeta. The specification does not enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and/or use the invention commensurate in scope with these claims.
The factors considered in determining whether a disclosure would require undue experimentation include:
(A) The breadth of the claims;
(B) The nature of the invention;
(C) The state of the prior art;
(D) The level of one of ordinary skill;
(E) The level of predictability in the art;
(F) The amount of direction provided by the inventor;
(G) The existence of working examples; and
(H) The quantity of experimentation needed to make or use the invention based on the content of the disclosure.
In re Wands, 8 USPQ2d, 1400 (CAFC 1988) and MPEP § 2164.01.
Nature of the invention/Breadth of the claims
Independent claim 1 is drawn to a genus of CARs that comprise an antigen binding domain specific for MSLN in combination with one or more antigen binding domains specific for an antigen selected from the group consisting of CLA, CD66c, TSPAN8 and CD318. This genus encompasses CARs that do and do not comprise transmembrane or intracellular signaling domains.
Dependent claims 3-5 are drawn to subgenera of CARs that comprise an antigen binding domain, a transmembrane domain, and an intracellular signaling domain.
Dependent claim 5 is further drawn to a subgenera of CARs wherein the transmembrane domain comprises a sequence of the transmembrane domains of 4-1BB, CD8 and/or CD28; and the intracellular signaling domain comprises a sequence of the intracellular signaling domains of one or more of CD28, CD137 and CD3zeta.
State of the prior art/Predictability of the art
Lindner et al. 2020 (Sci. Adv. 6: eaaz3223, 1-8) teach that the structure of a CAR minimally comprises an extracellular antigen recognition domain linked through a transmembrane domain to an intracellular activation domain or domains (e.g. see page 1, paragraph spanning left and right columns). Early CARs consisted of antibody single-chain variable fragments (scFvs) fused through a transmembrane domain to the cytoplasmic tail of the TCR signaling component CD3ζ; however, the addition of costimulatory signaling domains is required to achieve optimal clinical efficacy. CARs that incorporate a costimulatory domain membrane-proximal to the CD3ζ signaling domain are referred to as second-generation CARs. Third-generation CARs contain two in-line costimulatory domains, whereas fourth-generation CAR T cells typically incorporate separate cytokine signals. Second-generation CARs differ in their choice of costimulatory domain, which affects the efficacy, response phenotype, and metabolic properties of the resulting CAR T cells. The most frequently used costimulatory domains derive from the CD28 family (CD28 and ICOS, Inducible T Cell Costimulator) and the tumor necrosis factor receptor (TNFR) family (4-1BB (also known as CD137), CD27, and OX40) (e.g. see page 1, paragraph spanning left and right columns).
It is noted that the almost all CAR constructs contain the intracellular CD3ζ domain, which contains three immunoreceptor tyrosine-based activation motifs (ITAMs) (e.g. see paragraph spanning pages 2 and 3). The ITAMs are critical for CAR T cell activation (e.g. see page 2, paragraph spanning left and right columns; and the paragraph spanning pages 2 and 3).
Lindner et al. also teach that CARs comprise a transmembrane domain derived from a single source, such as CD8 or CD28 (e.g. see the green transmembrane domain in the CARs in Figure 1 and page 4, paragraph spanning left and right columns).
Thus, the art ultimately teaches that a CAR must comprise three critical domains: (1) an antigen binding domain; (2) a transmembrane domain; and (3) an intracellular signaling domain. It is noted that the transmembrane domain is derived from a single source. Moreover, the intracellular signaling domain must at the very least comprise an ITAM-containing signaling molecule, such as a CD3 molecule, for proper T-cell activation, but may also comprise costimulatory domains.
Working examples/Guidance in the specification
The instant disclosure teaches that CARs comprise a single chain fragment variable (scFv) of an antibody specific for a tumor associated antigen (TAA) coupled via hinge and transmembrane regions to cytoplasmic domains of T-cell signaling molecules (e.g. see [0003]). For example, well known lymphocyte activation moieties include a T-cell costimulatory (e.g. CD28, CD137, OX40, ICOS, and CD27) domain in tandem with a T-cell triggering (e.g. CD3zeta) moiety (e.g. see [0003]).
The Applicant recites that the CAR according to the invention may comprise an antigen binding domain conjugated to a transmembrane domain and/or an intracellular signaling domain, as shown by way of example in Fig. 1 (e.g. see [0036]). It is noted that the CAR models disclosed by the Applicant in Figures 1 and 2 all comprise a transmembrane domain and an intracellular signaling domain. In Figure 2, the Applicant discloses that all of CARs comprise a CD3zeta and a costimulatory domain (4-1BB). It is further noted that in Figure 2B, which depicts a split CAR comprising two distinct molecules, that the CAR can comprise two distinct transmembrane domains and two district intracellular signaling domains, one that comprises CD3zeta and the other that comprises 4-1BB, which work in concert.
The Applicant discloses that the transmembrane domain of the CAR can be derived from any desired natural or synthetic source for such domain (e.g. see [0060]). If the source is natural the domain may be derived from any membrane-bound or transmembrane protein. The transmembrane domain may be derived for example from CD8alpha or CD28 (e.g. see [0060]).
The Applicant also discloses that the cytoplasmic domain or the intracellular signaling domain of the CAR of the invention is responsible for activation of at least one of the normal effector functions of the immune cell in which the CAR is expressed (e.g. see [0061]). Prominent examples of intracellular signaling domains for use in the CARs include the cytoplasmic sequences of the T cell receptor (TCR) and co-receptors that act in concert to initiate signal transduction following antigen receptor engagement (e.g. see [0062]). Generally, T cell activation can be mediated by two distinct classes of cytoplasmic signaling sequence, firstly those that initiate antigen-dependent primary activation through the TCR (primary cytoplasmic signaling sequences) and secondly those that act in an antigen-independent manner to provide a secondary or co-stimulatory signal (secondary cytoplasmic signaling sequences) (e.g. see [0063]). Primary cytoplasmic signaling sequences that act in a stimulatory manner may contain ITAMs (immunoreceptor tyrosine-based activation motifs signaling motifs) (e.g. see [0064]). Examples of ITAM containing primary cytoplasmic signaling sequences often used in chimeric antigen receptor (CAR) derived from TCR zeta, FcR gamma, FcR beta, CD3 gamma , CD3 delta, CD3 epsilon, CDS, CD22, CD79a, CD79b, and CD66d (e.g. see [0065]).
The cytoplasmic domain of the CAR can comprise a CD3 zeta chain portion and a costimulatory signaling region. The costimulatory signaling region refers to a part of the CAR comprising the intracellular domain of a costimulatory molecule (e.g. see [0066]). A costimulatory molecule is a cell surface molecule other than an antigen receptor or their ligands that is required for an efficient response of lymphocytes to an antigen. Examples for costimulatory molecule are CD27, CD28, 4-1BB (CD137), 0X40, CD30, CD40, PD-1, ICOS, lymphocyte function-associated antigen-1 (LFA-1), CD2, CD7, LIGHT, NKG2C, B7-H3 (e.g. see [0066]).
It is noted that the Applicant has not disclosed explicitly disclosed that the CARs used in the only working example comprise a transmembrane domain and an intracellular signaling domain (e.g. see [00155] – [00168]).
Amount of experimentation necessary
The instant specification discloses several model CAR structures in Figures 1 and 2 which all comprise a transmembrane domain and an intracellular signaling domain. All of the CAR structures in Figure 2 comprise a CD3zeta signaling domain and a costimulatory domain (4-1BB). Furthermore, the split CAR depicted in Figure 2B comprises two distinct transmembrane domains and two district intracellular signaling domains, one that comprises CD3zeta and the other that comprises the costimulatory domain of 4-1BB, which work in concert.
However, the claims are not limited to CARs that comprise an antigen binding domain, a transmembrane domain comprising one sequence of the transmembrane domains of 4-1BB, CD8, or CD28, and an intracellular signaling domain comprising a sequence of the intracellular signaling domains of CD3zeta and CD28 and/or CD137.
The claimed genus of CARs encompass those that (1) do not comprise a transmembrane domain or an intracellular signaling domain; (2) comprise more than one sequence of the transmembrane domains of 4-1BB, CD8, and/or CD28; or (3) comprise a sequence of the intracellular signaling domains of one or more of CD28, CD137, and CD3zeta.
There is insufficient objective evidence that the disclosed CARs can be extrapolated to provide guidance and direction for how to make and/or use a CAR that (1) does not comprise a transmembrane domain or an intracellular signaling domain; (2) comprises more than one sequence of the transmembrane domains of 4-1BB, CD8, and/or CD28; or (3) comprises a sequence of the intracellular signaling domains of one or more of CD28, CD137, and CD3zeta.
Thus, based on the content of the disclosure in view of the prior art which teaches that a CAR must comprise three critical domains: (1) an antigen binding domain; (2) a transmembrane domain comprising a sequence derived from a single source; and (3) an intracellular signaling domain comprising at least an ITAM-containing signaling molecule, such as a CD3 molecule, a skilled artisan, through extensive trial-and-error experimentation, would have to make a CAR that does not comprise a transmembrane domain or an intracellular signaling domain; comprises more than one transmembrane sequence; or comprises an intracellular signaling domain that does not comprise an ITAM-containing signaling molecule (i.e. CD3zeta); and then use CARs in a T cell with a reasonable expectation of success. However, as it has been noted above, the transmembrane domain is required to link the extracellular antigen recognition domain to the intracellular activation domain or domains and anchor the CAR to the T cell. Furthermore, almost all CAR constructs contain the intracellular CD3zeta domain, which contains three ITAMs are critical for CAR T cell activation. It is noted that CD28 and CD137 (4-1BB) are costimulatory molecules that do not comprise ITAMs. Thus, this quantity of experimentation goes beyond what is considered “a reasonable degree of experimentation” and constitutes undue further experimentation in order to enable the CAR for the breadth of what is claimed.
Thus, the specification does not enable one of ordinary skill in the art to make and/or use what is claimed and therefore claims 1, 2, and 5-13 are rejected under 35 U.S.C. 112(a).
Amending claim 1 to recite in the body of the claim that the CAR also comprises a transmembrane domain and intracellular domain in addition to the already recited antigen binding domain; and amending claim 5 to recite that the transmembrane comprises a sequence from a single source (i.e. 4-1BB) and that the intracellular signaling domain comprises at least a CD3zeta signaling domain would obviate this part of the rejection.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1, 3-5, and 8-12 are rejected under 35 U.S.C. 103 as being unpatentable over Zhang et al. 2018 (J. Hematol. Oncol. 11(102), 1-14) in view of Beauchemin and Arabzadeh 2013 (Cancer Metastasis Rev. 32, 643–671).
Instant claim 1 is drawn to a chimeric antigen receptor (CAR), comprising an antigen binding domain specific for MSLN in combination with one or more antigen binding domains specific for an antigen selected from the group consisting of CLA, CD66c, TSPAN8 and CD318.
Claim 3 further limits the genus of CARs to those that comprise a transmembrane domain and an intracellular signaling domain.
Claim 4 further limits the genus of CARs to those that comprise either the same or different transmembrane domains and an intracellular signaling domains for the different antigen binding domains.
Claim 5 further limits the genus of CARs to those that comprise a transmembrane domain comprising a sequence of the transmembrane domains of 4-1BB, CD8 and/or CD28 and an intracellular signaling domain comprising a sequence of the intracellular signaling domains of one or more of CD28, CD137 and CD3zeta.
Claim 8 is drawn to a method of binding a cancer cell with the CAR.
Claim 9 is drawn to a population of engineered cells expressing at least one of the CARs.
Claim 10 is drawn to the use of the population of engineered cells or treating human cancer.
Claim 11 is drawn to a pharmaceutical composition comprising the population of engineered cells.
Claims 12 is drawn to the use of the pharmaceutical composition according to claim 11 for treatment of human cancer.
Regarding claims 1, 2, 8, and 9, Zhang et al. teach dual-receptor CAR-modified T cells (dCAR-T) that target carcino-embryonic antigen (CEA) and mesothelin (MSLN) and exert significant cytotoxicity only in the presence of cognate tumor cells (AsPC-1) expressing both CEA and MSLN, which is comparable with that obtained with conventional CAR-T cells and alleviates “on-target, off-tumor” toxicity (e.g. see conclusions on page 13). Zhang et al. teach that combination therapy using two distinct tumor-associated antigens (TAAs) to regulate dCAR-T cell activity is becoming increasingly prospective in the field of cell-based cancer immunotherapy (e.g. see conclusions on page 13).
Zhang et al. teach that the antigens used for CAR structure are often tumor-associated antigens co-expressed both on cancerous tissues and adjacent tissues; therefore, conventional CAR-T cells effectively kill tumor cells while also damaging normal tissues expressing the targeted antigen (e.g. see page 11, left column, first paragraph under “discussion”). This is known as “on-target, off-tumor” toxicity. In general, the two signaling domains derived from the intracellular part of T cell receptors are connected in a tandem manner and controlled by a targeted-antigen receptor; therefore, one antigen can control the two signaling domains, which increases the chance of damaging normal cells expressing the antigen of interest (e.g. see page 11, left column, first paragraph under “discussion”).
To achieve safer cytotoxicity of CAR-T cells, Zhang et al. designed the CEA-MSLN-dCAR-T cells for controlled activation of the T cell receptors (e.g. see page 11, left column, second paragraph under “discussion” and Figure 4). Their dCAR model contains two physically separate CD3ζ (CEA) and 4/1BB (MSLN) signaling domains (e.g. see page 11, left column, second paragraph under “discussion” and Figure 4).
Zhang et al.’s engineered T cells are not (fully) activated when only one of the antigens are bound (e.g. see page 11, paragraph spanning the left and right columns). For example, when only MSLN is bound this triggers phosphorylation of the intracellular 4/1BB signal domain but does not initiate T cell activation because the first signaling pathway (CD3ζ), which is not activated, is vital for the activity of T cells Hence, the dCAR-engineered T cells have no cytotoxicity for normal tissues expressing only the TAA MSLN (e.g. see page 11, paragraph spanning the left and right columns).
Similar to the first generation of CAR-T cells, the dCAR-T cells designed by Zhang et al. have low-level activation in the presence of only the CEA antigen, resulting in lower cytotoxicity against target cells (e.g. see page 11, paragraph spanning the left and right columns). Therefore, the co-stimulatory signaling pathway (MSLN-4/1BB) in the novel dCAR is crucial for complete activation of the engineered T cells (e.g. see page 11, paragraph spanning the left and right columns).
Zhang et al. teaches that their engineered T cells bearing the activated CD3ζ signaling pathway have a potential to exert cytotoxicity for CEA single-positive target cells (e.g. see page 11, right column, second paragraph). Thus, in order to further improve the safety of the dCAR-T cell therapy, Zhang et al. teach that the CD3ζ signaling pathway of dCAR structure can be modified to be more precisely regulated (e.g. see page 11, right column, second paragraph). Dual-targeted CAR-T cells can be localized exactly to a tumor site and can exert high cytotoxicity against tumor cells while the adjacent tissues are not damaged, enabling accurate application of CAR-T cell therapy (e.g. see paragraph spanning pages 11 and 12).
Regarding claims 3-5, it is noted that Zhang et al.’s CARs include an antigen-binding domain (anti-MSLN or anti-CEA scFv), a transmembrane domain (CD8α), and an intracellular signaling domain (4/1BB or CD3ζ) (e.g. see page 3, left column, first paragraph under “construction of plasmids”; and Figures 1a and b). Additionally, regarding claims 10-12, the dCAR-T cells were infused intravenously (i.e. as a pharmaceutical composition) in xenograft mouse models to characterize the tumor killing effect of the dCAR-T cells in vivo (e.g. see page 4, paragraph spanning left and right columns).
Zhang et al. do not teach that their CEA-MSLN-dCAR-T cells target CLA, CD66c, TSPAN8, or CD318 instead of CEA.
Beauchemin and Arabzadeh teach that CEACAM6 (also known as CD66c) is a CEA-related family member (e.g. see paragraph spanning pages 643 and 644). CD66c expression is more abundant than CEA in breast, pancreatic, mucinous ovarian, gastric, and lung adenocarcinomas, whereas its abundance is similar in prostate cancer to its normal counterpart and might be the most specific marker of this large protein family for a number of aggressive cancers (e.g. see paragraph spanning pages 645 and 646).
CD66c is known as a prognostic marker and therapeutic target (e.g. see page 650, paragraph spanning left and right columns). CD66c is an independent predictor of poor overall survival and disease-free survival in patients with colorectal cancer and an important regulator of metastasis (e.g. see page 650, paragraph spanning left and right columns). CD66c is also known to play a significant role in breast cancer, multiple myeloma, lung adenocarcinomas, and pancreatic cancer (e.g. see page 650, right column, second paragraph; and paragraph spanning pages 650 and 651).
Thus, Beauchemin and Arabzadeh teach that CD66c is a significant TAA in several cancers and is a promising therapeutic target.
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Zhang et al. to incorporate the teachings of Beauchemin and Arabzadeh to include that Zhang et al.’s CEA-MSLN-dCAR-T cells target CD66c instead of CEA. Given that CD66c is a significant TAA in many types of cancer, including colorectal cancer; CD66c is more abundantly expressed in breast, pancreatic, mucinous ovarian, gastric, and lung adenocarcinomas than CEA; and Zhang et al.’s desire to modify the CEA portion of the CAR which bears the CD3ζ signaling domain in order to improve the safety of their dCAR-T cell therapy; it would have been obvious to a skilled artisan to experiment with substituting the CEA antigen binding domain of Zhang et al.’s CEA-MSLN-dCAR-T cells with a CD66c antigen binding domain with a reasonable expectation of success.
Therefore, the invention as a whole was prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention, as evidenced by the references, especially in the absence of evidence to the contrary.
Claim 2 is rejected under 35 U.S.C. 103 as being unpatentable over Zhang et al. 2018 (J. Hematol. Oncol. 11(102), 1-14) in view of Beauchemin and Arabzadeh 2013 (Cancer Metastasis Rev. 32, 643–671), as applied to claim 1, and further in view of Kim et al. 2015 (Biochem. Biophys. Res. Commun. 468(4), 774-780).
Claim 2 further limits the genus of CARs of claim 1 to those that comprises antigen binding domain specific for MSLN in combination with at least two antigen binding domains specific for at least two different antigens selected from the group consisting of CLA, CD66c, TSPAN8 and CD318.
The combined teachings of Zhang et al. in view of Beauchemin and Arabzadeh pertaining to claim 1 and the rationale for combining them are outlined in the 103 rejection above.
The combined reference teachings differ from the instant invention only by not teaching that the dCAR-T cells can target more than two antigens, i.e. MSLN, CD66c, and CLA, TSPAN8, or CD318.
Kim et al. teach that Tetraspanin 8 (TSPAN8), a member of the tetraspanin superfamily, is a TAA that is highly overexpressed in several types of cancers including colorectal, liver, pancreatic, and gastric cancers (e.g. see page 774, right column, third paragraph). TSPAN8 plays a role in a variety of cancer cell functions, including cancer cell survival, migration, metastasis, and tumor angiogenesis (e.g. see page 774, right column, third paragraph). Kim et al. teach that TSPAN8 is critical for regulating metastatic colorectal cancer (mCRC) cell invasion and found that an anti-TSPAN8 antibody inhibited the invasion of mCRC cells more potently than that of non-mCRC cells (e.g. see paragraph spanning pages 774 and 775). Thus, Kim et al. teach that TSPAN8 is a potential therapeutic target in mCRC cell invasion (e.g. see paragraph spanning pages 774 and 775).
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the combined teachings of Zhang et al. in view of Beauchemin and Arabzadeh pertaining to claim 1 to incorporate the teachings of Kim et al. to include that the dCAR-T cells can target more than two antigens, i.e. MSLN, CD66c, and CLA, TSPAN8, or CD318.
Zhang et al. teach that the safety of their dCAR-T cell therapy can be further improved by modifying the portion of the CAR bearing the CD3ζ signaling domain so that it may be precisely regulated. Given that Zhang et al.’s dCAR T cell design is meant to improve “on-target, off-tumor” toxicity of CAR T cells while maintaining potent tumor specific cytotoxicity by separately controlling the intracellular signaling domains of the CAR with different antigens; it would be obvious to a skilled artisan, with the goal of further alleviating the “on-target, off-tumor” toxicity of the dCAR T cells, to experiment with adding additional antigen binding domains with a reasonable expectation of success. A skilled artisan would reasonably expect that an additional antigen binding domain could further restrict the interaction of the CAR to a specific tumor, especially given that tumors generally display aberrant expression of a variety of antigens.
These antigens includes TSPAN8 which is highly overexpressed in several types of cancers including colorectal, liver, pancreatic, and gastric cancers and is critical for regulating mCRC cell invasion (Kim et al.) In fact, TSPAN8 has been identified as a potential therapeutic target in mCRC. Therefore, the addition of another antigen binding domain that binds a TAA that is not CD66c or MSLN, such as TSPAN8, would presumably further alleviate the “on-target, off-tumor” toxicity of CAR T cells by increasing the number of antigens that are required to be bound before the cytotoxic activity of the T cell is unleashed.
Furthermore, the additional antigen binding domain could also be conjugated to an additional intracellular signaling domain which a skilled artisan would reasonably expect could provide another antigen-specific activation signal to the T cells thereby enhancing the overall cytotoxic activity toward the tumor of interest.
Combining prior art elements according to known methods to yield predictable results is obvious to one of ordinary skill in the art (see MPEP § 2143(A)). From the combined teachings of the references, it is apparent that one of ordinary skill in the art would have had a reasonable expectation of success in producing the claimed invention.
Therefore, the invention as a whole was prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention, as evidenced by the references, especially in the absence of evidence to the contrary.
Claims 6 and 7 rejected under 35 U.S.C. 103 as being unpatentable over Zhang et al. 2018 (J. Hematol. Oncol. 11(102), 1-14) in view of Beauchemin and Arabzadeh 2013 (Cancer Metastasis Rev. 32, 643–671), as applied to claims 1 and 3-5, and further in view of Kaiser et al. 2018 (WO 2018078066 A1) and Kim et al. 2015 (Biochem. Biophys. Res. Commun. 468(4), 774-780).
Claim 6 is drawn to the CAR of claim 1, wherein the CAR comprises an anti-tag binding region which can bind to a tag which is coupled to the antigen binding domain specific for one or more antigens selected from the group consisting of MSLN, CLA, CD66c, TSPAN8 and CD318.
Claim 7 further limits the genus of CARs of claim 6 to those that comprises antigen binding domai