Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on June 9, 2026, has been entered.
Election/Restrictions
Applicant’s election without traverse of Group I (Claims 1-20 and 23-30; drawn to a method of linking two or more viral vectors) in the reply filed on January 24, 2025, is acknowledged.
Applicant further elected the following species:
a. A method of linking two or more viral vectors (Species A1; claims 1-20)
b. Species A1A (claims 3-5 and 7-14)
Furthermore, Applicant provisionally elected SPAAC as the reaction for covalent linkage in a telephonic interview with their representative, Ina Agaj, on January 31, 2025.
Claims 12-14 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected inventions or species, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on January 24, 2025.
DETAILED ACTION
The amended claims filed on June 9, 2026, have been acknowledged. Claims 6 and 15-30 were cancelled. Claim 1 was amended. Claims 12-14 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected species, there being no allowable generic or linking claim. Claims 1-5 and 7-11 are pending and examined on the merits.
Rejections and/or objections not reiterated from the previous office action mailed March 9, 2026, are hereby withdrawn. The following rejections and/or objections are either newly applied or are reiterated and are the only rejections and/or objections presently applied to the instant application.
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 applicant claims domestic priority from U.S. provisional application No. 63/584,196, filed on September 21, 2023. Applicant’s claim for the benefit of a prior-filed application under 35 U.S.C. 119(e) or under 35 U.S.C. 120, 121, 365(c), or 386(c) is acknowledged. Claims 1-5 and 7-11 receive domestic benefit from U.S. provisional application No. 63/584,196, filed on September 21, 2023.
Claim Rejections - 35 USC § 112
New Matter
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 1-5 and 7-11 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(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for 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.
As an initial matter, this rejection is based on the interpretation that ex vivo does not encompass the column based viral vector linking used by United States Patent Application No. 20200224219 (Buning), as argued by the Applicant (Applicant argues that Buning does not teach the combining step is performed "ex vivo" to form a "covalently linked vector composition prior to administration to a subject." (page 2, paragraph 2 of Applicant’s Remarks)).
Claim 1, amended on June 9, 2026, recites “A method of linking together two or more virus vectors for co-delivery in a cell in gene therapies, the method comprising:… combining the first functionalized virus vector and second functionalized virus vector ex vivo to form a covalently linked vector composition prior to administration to a subject…”.
Applicant argues that their amendment clarifies and makes explicit what is inherent in and fully supported by the as-filed specification, which describes the linking method as an entirely in vitro/ex vivo preparation process. See, e.g., specification at paragraphs [0050]-[0060] (describing the ex vivo functionalization and coupling protocol using NHS-dPEG-Azide and NHS-dPEG-DBCO linkers in centrifugal column procedures (page 1, paragraph 6-page 2, paragraph 1 of Applicant’s Remarks). As Applicant uses a centrifugal column for linking two vectors and the Applicant argues that this method is inherently an ex vivo method, as identified in Examples A and B, the column based method of linking two viral vectors of Buning is also considered to be an ex vivo method. Applicant also argues that United States Patent Application No. 20200224219 (Buning) does not teach the combining step is performed "ex vivo" to form a "covalently linked vector composition prior to administration to a subject." (page 2, paragraph 2 of Applicant’s Remarks). However, Buning also uses a column based method of linking the viral vectors (See Figure 3 and paragraphs 0118-0122). As such, these appear to be contradictory arguments. Either column-based linking of viral vectors is an ex vivo (as Applicant argues is inherent with their method) or it is not (as Applicant argues regarding the method of Buning). As such, under the interpretation that column based viral vector linking is not an ex vivo method, the column based vector linking method of the instant application is not considered to be inherently be an ex vivo method. Therefore, clear support for the new limitation cannot be found in the instant application or priority documents.
Accordingly, the amendments to Claim 1 are considered to constitute new matter.
MPEP 2163.06 notes “If new matter is added to the claims, the examiner should reject the claims under 35 U.S.C. 112, first paragraph - written description requirement. In re Rasmussen, 650 F.2d 1212, 211 USPQ 323 (CCPA 1981).” MPEP 2163.02 teaches that “Whenever the issue arises, the fundamental factual inquiry is whether a claim defines an invention that is clearly conveyed to those skilled in the art at the time the application was filed...If a claim is amended to include subject matter, limitations, or terminology not present in the application as filed, involving a departure from, addition to, or deletion from the disclosure of the application as filed, the examiner should conclude that the claimed subject matter is not described in that application”. MPEP 2163.06 further notes “When an amendment is filed in reply to an objection or rejection based on 35 U.S.C. 112, first paragraph, a study of the entire application is often necessary to determine whether or not “new matter” is involved. Applicant should therefore specifically point out the support for any amendments made to the disclosure” (emphasis added).
In the remarks filed on June 9, 2026, Applicant identifies that the amendments are not new matter because the functionalization and coupling protocol using NHS-dPEG-Azide and NHS-dPEG-DBCO linkers in centrifugal column procedures is inherently an ex vivo preparation process. However, as noted above, Applicant also argues that the column based coupling protocol of Buning is not an ex vivo method. As such, under the interpretation that column based viral vector linking is not an ex vivo method, the column based vector linking method of the instant application is not considered to be inherently be an ex vivo method. Therefore, clear support for the new limitation cannot be found in the instant application or priority documents.
If Applicant believes that support for the new limitations, as now recited in Claim 1, is present and clearly envisaged in the instant application or earlier filed priority documents, applicant must, in responding to this Office Action, point out with particularity, where such support may be found.
Declarations and new references cannot demonstrate possession of a concept after the fact.
Claims 2-5 and 7-11 are also rejected because of their dependency on claim 1.
Claim Rejections - 35 USC § 102
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claims 1-5 and 7 are rejected under 35 U.S.C. 102(a)(1) and 102(a)(2) as being anticipated by United States Patent Application No. 20200224219 (Buning). This Is a new rejection made in response to Applicant’s amendments to claim 1 that is substantially similar to a previous rejection of record. Any aspect of Applicant’s traversal that is relevant to the new rejection of record is addressed below.
As an initial matter, this rejection is based on the interpretation that ex vivo does encompass column based viral vector linking, as argued by the Applicant (Applicant argues that their amendment clarifies and makes explicit what is inherent in and fully supported by the as-filed specification, which describes the linking method as an entirely in vitro/ex vivo preparation process. See, e.g., specification at paragraphs [0050]-[0060] (describing the ex vivo functionalization and coupling protocol using NHS-dPEG-Azide and NHS-dPEG-DBCO linkers in centrifugal column procedures) (page 1, paragraph 6-page 2, paragraph 1 of Applicant’s Remarks)). As Applicant uses a centrifugal column for linking two vectors and the Applicant argues that this method is inherently an ex vivo method, as identified in Examples A and B, the column based method of linking two viral vectors of Buning is also considered to be an ex vivo method.
Furthermore, regarding the limitation in claim 1 “for co-delivery in a cell in gene therapies,” this limitation is considered to be an “intended use” of the claimed viral vector composition produced by the method of claim 1, and not to be an active method step as there is not positively recited step of administering the linked vectors to a subject. Similarly, the limitation “combining the first functionalized virus vector and second functionalized virus vector ex vivo to form a covalently linked vector composition prior to administration to a subject” does not positively recite an administration step, only that the combining occurs prior to any possible administration to a subject. As such, this is also not considered to be an active method step of administering the linked vectors to a subject. See MPEP 2111.02. Nevertheless, Buning does disclose that the present invention relates to the use of the linked AAV vectors as a medicament for gene therapy (which would involve administering the linked vectors to a subject) (paragraphs 0063-0084).
Regarding claim 1, Buning teaches a method of linking two or more viral vectors wherein a purified non-infective viral vector (for example, Cys2ΔHSPG) is bound to a column. Then, Dibenzylcyclooctyne-PEG4 -Maleimide linker (first surface moiety) is added to the column for 3 hours and functionalizes with the non-infectious viral vector. After a wash step, azide-modified molecules (such as an azide functionalized (second surface moiety) infectious AAV vector; Buning teaches that the term "targeting molecule" refers to a molecule allowing targeting of AAV particles to target cells. Buning teaches that the infectious AAV particle allows transport of the non-infectious particle into the target cell, thus, increasing the capacity of DNA to be introduced into said cell. As such, the infectious AAV particle would be a targeting molecule) were added and incubated for 72 hours. After a final wash step, coupled vectors were eluted (paragraphs 0041, 0084, and 0121-0122). As can be seen on page 6, the azide and DBCO react to form a covalent linkage.
Regarding the nucleic acid constructs, Buning teaches a composition of an infectious AAV particle according to the present invention with an at least one non-infectious AAV particle enables trans-splicing technology or two component systems (i.e. connection of two or more vector genomes through a cellular splice event enlarging thereby the coding capacity of AAV vectors) to be used for transduction of target cells ex vivo or in vivo. The infectious particle coupled to a non-infectious particle, e.g. so-called receptor blinded particles as a complex, will guide the complex towards the cell and mediate cell infection of the whole complex including the non-infectious particles. Thus, this technique can overcome the limited capacity of AAV vectors enabling the transduction of cells with a dual vector system, thereby increasing the capacity of components introduced into the cells. Thus, it is possible to enable trans-splicing or two component systems in vivo.
That is, the infectious AAV particle can transport the non-infectious particle into the target cell, thus, increasing the capacity of DNA to be introduced into said cell accordingly.
Further, the present invention relates to the use of the AAV particle according to the present invention, as a medicament for gene therapy (which would involve administering the linked vectors to a subject) (paragraphs 0063-0084).
Regarding whether the covalent linkage is an ex vivo method, as stated supra, Applicant argues that that their method of covalently linking AAV vectors is an ex vivo method. Their method involves functionalizing their vectors in Microcon columns which Applicant identifies as an “ex vivo functionalization” (page 2, paragraph 1 of Remarks). As Buning uses columns to functionalize and link their viral vectors (as stated supra, Buning teaches that their method comprises a purified non-infective viral vector is bound to a column. Then, Dibenzylcyclooctyne-PEG4 -Maleimide linker (first surface moiety) is added to the column for 3 hours and functionalizes with the non-infectious viral vector. After a wash step, an azide-modified infectious AAV vector were added and incubated for 72 hours. After a final wash step, coupled vectors were eluted), the method of Buning would be an ex vivo method based on Applicant’s own consideration of what ex vivo encompasses.
Regarding claim 2, Buning teaches that their viral vectors were AAV2 viral vectors (paragraphs 0130-0131).
Regarding claims 3-5, Buning, as stated supra, teaches that they used a Dibenzylcyclooctyne (DBCO)-PEG4-Maleimide linker (first surface moiety) and azide linker (second surface moiety) for the covalent linkage reaction (this is a known SPAAC reaction).
Regarding claim 7, Buning, as stated supra, teaches on page 6 that the DBCO and azide reaction forms this linking structure between the first and second AAV vectors.
Response to Arguments
Applicant's arguments filed June 9, 2026, are acknowledged.
Applicant argues Amended claim 1 requires, inter alia, that: (1) the method is for "co-delivery in a cell in gene therapies"; (2) the first virus vector encapsulates a first nucleic acid construct and the second virus vector encapsulates a second nucleic acid construct; (3) the first and second nucleic acid constructs are "different segments from the same gene sequence"; and (4) the combining step is performed "ex vivo" to form a "covalently linked vector composition prior to administration to a subject." Buning discloses none of these limitations in combination.
The Examiner relies principally on paragraphs [0041], [0084], and [0121]-[0122] of Buning, which describe a laboratory demonstration in which two AAV particles are chemically coupled via DBCO-PEG4-Maleimide and azide linkers. However, this protocol is a proof-of principle demonstration of capsid reactivity and chemistry - not a gene therapy co-delivery strategy. Critically, Buning never discloses that the two coupled particles carry nucleic acid constructs that are different segments of the same gene sequence. Buning does not even identify the payload content of the two coupled particles for purposes of reconstituting a split transgene. No gene therapy co-delivery function is attributed to the chemical coupling in Buning; the stated purpose of coupling an infectious AA V to a non-infectious receptor-blinded particle is to guide the complex to target cells, not to ensure that two complementary gene segments are codelivered into the same cell for gene reconstitution (page 2, paragraph 2-page page 3, paragraph 1 of Remarks).
Applicant's arguments have been fully considered but they are not persuasive.
As an initial matter, Applicant is reminded that MPEP 2123 (I) states that patents are relevant as prior art for all they contain, and that a reference may be relied upon for all that it would have reasonably suggested to one having ordinary skill the art, including nonpreferred embodiments. “The use of patents as references is not limited to what the patentees describe as their own inventions or to the problems with which they are concerned. They are part of the literature of the art, relevant for all they contain.” In re Heck, 699 F.2d 1331, 1332-33, 216 USPQ 1038, 1039 (Fed. Cir. 1983) (quoting In re Lemelson, 397 F.2d 1006, 1009, 158 USPQ 275, 277 (CCPA 1968)). A reference may be relied upon for all that it would have reasonably suggested to one having ordinary skill the art, including nonpreferred embodiments. Merck & Co. v. Biocraft Laboratories, 874 F.2d 804, 10 USPQ2d 1843 (Fed. Cir.), cert. denied, 493 U.S. 975 (1989).
Regarding Applicant’s arguments that Buning does not teach certain limitations, each will be addressed below:
(1) the method is for "co-delivery in a cell in gene therapies":
As stated in the rejection above, regarding the limitation in claim 1 “for co-delivery in a cell in gene therapies,” this limitation is considered to be an “intended use” of the claimed viral vector composition produced by the method of claim 1, and not to be an active method step as there is not positively recited step of administering the linked vectors to a subject. Similarly, the limitation “combining the first functionalized virus vector and second functionalized virus vector ex vivo to form a covalently linked vector composition prior to administration to a subject” does not positively recite an administration step, only that the combining occurs prior to any possible administration to a subject. As such, this is also not considered to be an active method step of administering the linked vectors to a subject. See MPEP 2111.02. Nevertheless, Buning does disclose that the present invention relates to the use of the linked AAV vectors as a medicament for gene therapy (which would involve administering the linked vectors to a subject) (paragraphs 0063-0084).
(2) the first virus vector encapsulates a first nucleic acid construct and the second virus vector encapsulates a second nucleic acid construct:
As stated in the rejection above, regarding the nucleic acid constructs, Buning teaches a composition of an infectious AAV particle according to the present invention with an at least one non-infectious AAV particle enables trans-splicing technology or two component systems (i.e. connection of two or more vector genomes through a cellular splice event enlarging thereby the coding capacity of AAV vectors) to be used for transduction of target cells ex vivo or in vivo. The infectious particle coupled to a non-infectious particle, e.g. so-called receptor blinded particles as a complex, will guide the complex towards the cell and mediate cell infection of the whole complex including the non-infectious particles. Thus, this technique can overcome the limited capacity of AAV vectors enabling the transduction of cells with a dual vector system, thereby increasing the capacity of components introduced into the cells. Thus, it is possible to enable trans-splicing or two component systems in vivo.
Therefore, Buning does teach a first vector that encapsulates a first nucleic acid construct and a second vector encapsulates a second nucleic acid construct as trans-splicing would involve separate nucleic acid constructs in the two vectors that are spliced together once both genes are expressed in the cell together.
(3) the first and second nucleic acid constructs are "different segments from the same gene sequence":
As stated in the rejection above, regarding the nucleic acid constructs, Buning teaches a composition of an infectious AAV particle according to the present invention with an at least one non-infectious AAV particle enables trans-splicing technology or two component systems (i.e. connection of two or more vector genomes through a cellular splice event enlarging thereby the coding capacity of AAV vectors) to be used for transduction of target cells ex vivo or in vivo. The infectious particle coupled to a non-infectious particle, e.g. so-called receptor blinded particles as a complex, will guide the complex towards the cell and mediate cell infection of the whole complex including the non-infectious particles. Thus, this technique can overcome the limited capacity of AAV vectors enabling the transduction of cells with a dual vector system, thereby increasing the capacity of components introduced into the cells. Thus, it is possible to enable trans-splicing or two component systems in vivo.
Trans-splicing is known to be used to express a gene that is too large to be packaged in an AAV vector and Buning specifically identifies that their linked vectors enable trans-splicing technology or two component systems (i.e. connection of two or more vector genomes through a cellular splice event enlarging thereby the coding capacity of AAV vectors). As such, it is clear that the trans-splicing of Buning would carry different segments from the same gene for splicing together to enlarge the coding capacity.
(4) the combining step is performed "ex vivo" to form a "covalently linked vector composition prior to administration to a subject.":
As stated in the rejection above, regarding whether the covalent linkage is an ex vivo method, as stated supra, Applicant argues that that their method of covalently linking AAV vectors is an ex vivo method. Their method involves functionalizing their vectors in Microcon columns which Applicant identifies as an “ex vivo functionalization” (page 2, paragraph 1 of Remarks). As Buning uses columns to functionalize and link their viral vectors (as stated supra, Buning teaches that their method comprises a purified non-infective viral vector is bound to a column. Then, Dibenzylcyclooctyne-PEG4 -Maleimide linker (first surface moiety) is added to the column for 3 hours and functionalizes with the non-infectious viral vector. After a wash step, an azide-modified infectious AAV vector were added and incubated for 72 hours. After a final wash step, coupled vectors were eluted), the method of Buning would be an ex vivo method based on Applicant’s own consideration of what ex vivo encompasses.
Therefore, Buning is considered to teach each of the limitations that the Applicant argues are not taught by Buning.
Applicant further argues that Buning is focused entirely on modifying vector tropism and attaching detectable or therapeutic external ligands to individual capsid surfaces. It does not identify, address, or solve the problem of inefficient co-delivery of multiple viral vectors carrying complementary gene segments into the same cell (page 2, paragraph 3-page 3, paragraph 1 of Remarks).
Applicant's arguments have been fully considered but they are not persuasive.
As stated in the rejection above, regarding the nucleic acid constructs, Buning teaches a composition of an infectious AAV particle according to the present invention with an at least one non-infectious AAV particle enables trans-splicing technology or two component systems (i.e. connection of two or more vector genomes through a cellular splice event enlarging thereby the coding capacity of AAV vectors) to be used for transduction of target cells ex vivo or in vivo. The infectious particle coupled to a non-infectious particle, e.g. so-called receptor blinded particles as a complex, will guide the complex towards the cell and mediate cell infection of the whole complex including the non-infectious particles. Thus, this technique can overcome the limited capacity of AAV vectors enabling the transduction of cells with a dual vector system, thereby increasing the capacity of components introduced into the cells. Thus, it is possible to enable trans-splicing or two component systems in vivo.
Trans-splicing is known to be used to express a gene that is too large to be packaged in an AAV vector and Buning specifically identifies that their linked vectors enable trans-splicing technology or two component systems (i.e. connection of two or more vector genomes through a cellular splice event enlarging thereby the coding capacity of AAV vectors). Therefore, Buning directly contemplates that their linked vectors could be used to improve trans-splicing methods of delivering complementary gene segments into the same cell.
Applicant further argues that the Examiner maps the "infectious AA V particle" of Buning to the "second surface moiety" of claim 1, characterizing the infectious AA Vas a "targeting molecule." This mapping is legally and factually flawed. A surface moiety is a discrete chemical functional group appended to the capsid surface; it is not the virus vector itself. Buning' s infectious AAV would itself need to be functionalized with a surface moiety in order to satisfy this claim element. Buning does not disclose this (page 3, paragraph 3-page 4, paragraph 1 of Remarks).
Applicant's arguments have been fully considered but they are not persuasive.
As stated in the rejection above, Buning teaches a method of linking two or more viral vectors wherein a purified non-infective viral vector (for example, Cys2ΔHSPG) is bound to a column. Then, Dibenzylcyclooctyne-PEG4 -Maleimide linker (first surface moiety) is added to the column for 3 hours and functionalizes with the non-infectious viral vector. After a wash step, azide-modified molecules (such as an azide functionalized (second surface moiety) infectious AAV vector; Buning teaches that the term "targeting molecule" refers to a molecule allowing targeting of AAV particles to target cells. Buning teaches that the infectious AAV particle allows transport of the non-infectious particle into the target cell, thus, increasing the capacity of DNA to be introduced into said cell. As such, the infectious AAV particle would be a targeting molecule) were added and incubated for 72 hours. After a final wash step, coupled vectors were eluted (paragraphs 0041, 0084, and 0121-0122). As can be seen on page 6, the azide and DBCO react to form a covalent linkage.
As is identified in the rejection, the azide functionalization is the second surface moiety. This functionalization occurs with the infectious AAV vector. The vector itself is not considered the functional moiety. The azide molecule is considered the functional moiety. As identified in Applicant’s arguments, Buning' s infectious AAV would itself need to be functionalized with a surface moiety in order to satisfy this claim element. As Buning directly teaches that the infectious AAV can be functionalized with an Azide molecule, it satisfies the claim limitation.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
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.
Claims 1-2 and 8-11 are rejected under 35 U.S.C. 103 as being unpatentable over United States Patent Application No. 20200224219 (Buning) as applied to claims 1-2 above, and further in view of Nguyen et al. (International Journal of Pharmaceutics 605:1-19. 2021) and Mevel et al. (Chem. Sci. 11: 1122-1131. 2020). This is a new rejection that is substantially similar to a previous rejection of record. Any aspect of Applicant’s traversal that has not been addressed above is addressed below.
The teachings of Buning are as discussed above.
Although Buning discloses the use of NHS ester for crosslinking antibodies [0118], Buning does not teach wherein NHS esters are used as part of the linking structure between the AAV capsid.
Nguyen teaches that click chemistry refers to the formation of a stable triazole linkage by the reaction between alkyne and azide groups. To do so, a linker is normally used for connecting molecules. In most cases, the functionalization of molecules with azide or alkyne moieties goes through carbodiimide or maleimide conjugation. Therefore, NHS esters or maleimide groups needs to be present on one side of the linker, while azide or alkyne groups must be located on the other side. Furthermore, Nguyen references Kotagiri which specifically teaches using NHS-PEG-DBCO and NHS-PEG-Azide for conjugating different molecules onto amine coated quantum dots (page 11, paragraphs 3-4).
Mevel teaches that the grafting of a functionalized RGD peptide onto the capsid of a genetically modified AAV to specifically target tumor cells was reported. The results showed the possibility of attaching a ligand onto the capsid of AAV in order to improve its transduction efficiency for tumor cells. However, this approach required the introduction of an azide moiety into the AAV capsid by mutating the VP3 sequence and introducing unnatural amino acids. Consequently, the manufacturing of genetically modified AAV with this specific coupling functionality remains very demanding because it requires optimization of each step of production and purification, followed by complex characterization of the particles. An alternative approach is to develop engineered AAV through chemical strategies without the need to modify the amino acid composition of the AAV capsid. Lysine residues on the viral surface are most commonly exploited as a molecular anchor for conjugating amine-reactive molecules. For example, PEGylated AAV particles via amine functionalities have also been developed to protect the virus from neutralization and enable significant levels of gene expression upon re-administration without compromising the patient's immune system (page 1122, column 2, paragraph 3-page 1123, column 2, paragraph 1).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have substituted maleimide of Buning with an NHS ester, as identified by Nguyen, to arrive at the instantly claimed invention. One of ordinary skill in the art would have a reason to substitute with a reasonable expectation of success because Nguyen teaches that it was well understood in the art that maleimide or NHS esters are used for click chemistry (such as SPAAC) as part of the linker structure. Furthermore, Nguyen teaches that Kotagiri successfully reduced to practice that NHS-PEG-DBCO and NHS-PEG-Azide linkers could be used to couple different molecules. Furthermore, Bunning teaches that there were at least 12 different serotypes of AAV known in the art [0042], and the cysteine based chemistry of Bunning would have required cysteine substitution of each and every AAV capsid to be crosslinked, while the NHS/amine based chemistry of Nguyen would have allowed the use of wild type AAV capsids across the different serotypes without the need for cysteine modification. As identified by Mevel, the manufacturing of genetically modified AAV with specific coupling functionality remains very demanding because it requires optimization of each step of production and purification, followed by complex characterization of the particles. Mevel identifies that an alternative approach is to develop engineered AAV through chemical strategies without the need to modify the amino acid composition of the AAV capsid. Lysine residues on the viral surface are most commonly exploited as a molecular anchor for conjugating amine-reactive molecules. Thus, the omission of the cysteine modification step would have been obvious to one having ordinary skill in the art at the time the invention was filed since it has been held that omission of an element and its function is obvious if the function of the element is no longer needed (see MPEP 2144.04 (II)). Furthermore, Mevel identifies that amine based conjugation of AAV particles has already shown to lead to significant levels of gene expression upon re-administration without compromising the patient's immune system and that their conjugation modifications to lysine residues were also successful in leading to gene expression in cells (whole document). As such, amine based conjugation of molecules to AAV vectors was well understood within the field to be a viable option for chemical conjugation with successful gene expression in cells and it was understood to be a simpler option for click chemistry as the targeted lysine residues do not require chemical modification. Therefore, it would have been obvious to one of ordinary skill in the art that NHS esters could have been used as part of the linking structure instead of maleimide with a reasonable expectation of success. Because the prior art teaches all of the elements of the claimed invention, there is a reasonable expectation of success.
Regarding claims 8 and 9, the specification discloses that NHS esters are capable of attaching to amine groups on a capsid protein (paragraph 0060).
Regarding claims 10-11, replacing the maleimide would result in a linking structure of NHS-PEG4-DBCO ester.
Response to Arguments
Applicant's arguments filed June 9, 2026, are acknowledged.
Applicant argues Nguyen is directed to the surface functionalization of nanomedicines – specifically polymeric nanoparticles and liposomes - with anti-EGFR antibody ligands for targeted cancer therapy. The reference concerns nanoparticle drug delivery systems and cancer-targeting conjugation strategies, not viral vector gene therapy. Nguyen is not in the same field of endeavor as the present invention (gene therapy using covalently linked viral vectors for split-gene codelivery), nor is it reasonably pertinent to the particular problem the inventors faced (ensuring co-delivery of two complementary gene segments into the same cell via pre-linked viral particles) (page 5, paragraph 2 of Remarks).
Applicant's arguments have been fully considered but they are not persuasive.
Buning and Nguyen are analogous art as both are related to the use of click chemistry to conjugate molecules together to generate pharmaceutical compositions. Although Nguyen is not directed to linking viral vectors together, it would be well understood within the field that the teachings of Buning and Nguyen regarding click chemistry would be relevant to other methods of conjugating molecules using SPAAC click chemistry. Therefore, as Buning and Nguyen are related to using SPAAC click chemistry to conjugate molecules together to generate pharmaceutical compositions, they are considered analogous art.
Applicant further argues that the rationale for substituting maleimide (Buning) with an NHS ester (Nguyen/Kotagiri) is flawed. First, Buning' s maleimide-based chemistry is specifically designed for and dependent upon engineered cysteine residues expressed on the AA V capsid surface. Substituting NHS ester chemistry would not be a simple one-for-one substitution; it would require abandoning Buning's entire cysteine-based capsid engineering approach and redesigning the surface functionalization system from the ground up. This is not a routine modification; it is a fundamental redesign of Buning's methodology. Second, the Examiner's own rationale highlights why the two chemistries are not interchangeable: NHS/amine-based chemistry would allow use of wild-type AAV capsids without cysteine modification, while Buning' s approach requires cysteine modification of each serotype. These are structurally different approaches that solve different problems. A person of ordinary skill would be just as likely to select one approach over the other for independent reasons - there is no specific technical motivation identified by the Examiner to apply NHS chemistry to Buning' s viral capsid coupling system, as opposed to the non-viral nanoparticle systems where Nguyen's teaching originates. Third, the Examiner asserts a "reasonable expectation of success" but provides no evidentiary basis specific to coupling intact, functional AAV capsids carrying complementary gene segments via NHS ester chemistry while preserving the infectivity of the coupled viral complex. Citing known chemistry in a different context ( coupling antibodies to nanoparticles) does not establish a reasonable expectation of success in the specific and distinct context of the claimed invention (page 5, paragraph 3-page 6, paragraph 3 of Remarks).
Applicant's arguments have been fully considered but they are not persuasive.
As stated in the rejection above, Nguyen teaches that it was well understood in the art that maleimide or NHS esters are used for click chemistry (such as SPAAC) as part of the linker structure. Furthermore, Nguyen teaches that Kotagiri successfully reduced to practice that NHS-PEG-DBCO and NHS-PEG-Azide linkers could be used to couple different molecules. Furthermore, Bunning teaches that there were at least 12 different serotypes of AAV known in the art [0042], and the cysteine based chemistry of Bunning would have required cysteine substitution of each and every AAV capsid to be crosslinked, while the NHS/amine based chemistry of Nguyen would have allowed the use of wild type AAV capsids across the different serotypes without the need for cysteine modification. As identified by Mevel, the manufacturing of genetically modified AAV with specific coupling functionality remains very demanding because it requires optimization of each step of production and purification, followed by complex characterization of the particles. Mevel identifies that an alternative approach is to develop engineered AAV through chemical strategies without the need to modify the amino acid composition of the AAV capsid. Lysine residues on the viral surface are most commonly exploited as a molecular anchor for conjugating amine-reactive molecules. Thus, the omission of the cysteine modification step would have been obvious to one having ordinary skill in the art at the time the invention was filed since it has been held that omission of an element and its function is obvious if the function of the element is no longer needed (see MPEP 2144.04 (II)).
Thus there is a clear technical motivation for substituting maleimide with NHS/amine-based chemistry as this would allow use of wild-type AAV capsids without cysteine modification as the manufacturing of genetically modified AAV with specific coupling functionality remains very demanding because it requires optimization of each step of production and purification, followed by complex characterization of the particles.
Furthermore, Mevel identifies that amine based conjugation of AAV particles has already shown to lead to significant levels of gene expression upon re-administration without compromising the patient's immune system and that their conjugation modifications to lysine residues were also successful in leading to gene expression in cells (whole document). As such, amine based conjugation of molecules to AAV vectors was well understood within the field to be a viable option for chemical conjugation with successful gene expression in cells and it was understood to be a simpler option for click chemistry as the targeted lysine residues do not require chemical modification. Therefore, there is a reasonable expectation of success.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to KEENAN A BATES whose telephone number is (571)270-0727. The examiner can normally be reached M-F 7:30-5:00.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Doug Schultz can be reached on (571) 272-0763. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/KEENAN A BATES/Examiner, Art Unit 1631
Prosecution Insights