DETAILED ACTION
Non-Final Rejection
Notice of Pre-AIA or AIA Status
1. The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Status of claims
2. Claims 1-20 as filed on 06/14/2023 are pending.
3. Claims 1-20 as filed on 06/14/2023 are under examination.
Priority
4. This application is a national stage application of International Patent Application No. PCT/US2021/063647 filed December 16, 2021, which claims the benefit of U.S. Provisional Patent Application No. 63/211,162 filed June 16, 2021; International Patent Application No. PCT/US2020/065572 filed December 17, 2020; and U.S. Provisional Patent Application No. 63/126,743, filed December 17, 2020.
Information Disclosure Statement
5. The information disclosure statement (IDS) submitted on 04/09/2024 is in compliance with the provisions of 37 CFR 1.97 and accordingly, the information disclosure statement is being considered by the examiner.
Claim Interpretation
6. The claims in this application are given their broadest reasonable interpretation using the plain meaning of the claim language in light of the specification as it would be understood by one of ordinary skill in the art. The broadest reasonable interpretation of a claim element (also commonly referred to as a claim limitation) is limited by the description in the specification when 35 U.S.C.
Claim 1: The claim 1 is interpreted to be directed to a method of cation exchange chromatography for purification of an enterovirus that is based on isoelectric point of entire enterovirus proteins. The method comprises the steps of: (a) binding the enterovirus to a cation exchange stationary phase using a loading solution with a pH of about 3.5 to 6.0; (b) eluting the enterovirus from the stationary phase with an elution solution with a pH of about 3.5 to 4.8.
Claim 20: The claim 20 is interpreted to be directed to a method of purifying an enterovirus comprising the steps of: (a) applying a loading solution comprising the enterovirus to a cation exchange stationary phase using a loading solution with a pH of about 3.5 to 4.7; (b) collecting the flow-through comprising the enterovirus. This method combines binding and elution of the enterovirus using the same buffer with a pH of about 3.5 to 4.7.
The claimed methods of cation exchange chromatography for purification of an enterovirus are based on isoelectric point of enterovirus (all proteins of enterovirus assembled as an enterovirus enclosing nucleic acid). The isoelectric point of different viruses and strain within the enterovirus genus of the family Picornaviridae are expected to be similar and vary to limited extent based on the amino acid composition of the viruses belonging to the same genus and thereby expected to have a similar isoelectric point of a viral species within a genus enterovirus.
Claim Objections
7. Claim 9 is objected to because of the following informalities:
The claim limitation “PS” in PS-80 and PS-20 should be used at least once in the claim to its full name “polysorbate”.
Appropriate correction is required.
Objection to Specification
8. The listing of references in the specification is not a proper information disclosure statement. 37 CFR 1.98(b) requires a list of all patents, publications, or other information submitted for consideration by the Office, and MPEP § 609.04(a) states, "the list may not be incorporated into the specification but must be submitted in a separate paper." Therefore, unless the references have been cited by the examiner on form PTO-892, they have not been considered.
The specification filed on 06/14/2023 on page numbers 47-48 has listed 18 references that should have been listed in the IDS.
Claim Rejections - 35 USC § 112
9. 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 9-11 and 19 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.
The instant claim 9 and dependent claims 10-11 contains the trademark / trade name PS-80 or PS-20. The instant claim 19 contains the trademark/trade name PorosTM 50 HS. Where a trademark or trade name is used in a claim as a limitation to identify or describe a particular material or product, the claim does not comply with the requirements of 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph. See Ex parte Simpson, 218 USPQ 1020 (Bd. App. 1982). The claim scope is uncertain since the trademark or trade name cannot be used properly to identify any particular material or product. A trademark or trade name is used to identify a source of goods, and not the goods themselves. Thus, a trademark or trade name does not identify or describe the goods associated with the trademark or trade name. In the present case, the trademark / trade name is used to identify / describe “a surfactant” (claims 9-11), and “cationic resin” (claim 19) and, accordingly, the identification/description is indefinite.
Claim Rejections - 35 USC § 102
10. 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.
Claim 20: The instant claim 20 is rejected under 35 U.S.C. 102(a)(1)/(a)(2) as being anticipated by Segers et al 2016 (WO 2016012445A2, 01/28/2016).
Segers et al 2016 teaches a method of purifying a poliovirus (an enterovirus) from crude cell culture harvests using a detergent followed by a clarification. The clarified poliovirus particle comprising harvest (refereed as feed material) is adjusted to an acidic pH ranging from 4.4 to 5.6 (instant claimed pH of about 3.5 to 4.7). Subsequently, adjusted feed material is loaded to a cation exchange chromatography membrane adsorber where the virus selectively binds to the membrane. Virus particles are further purified from impurities in the following elution step by increasing the ionic strength of the elution buffer while maintaining the pH range constant between 4.4-5.6 (See, abstract, page 14 lines 24-35, claims 1-4).
Claim Rejections - 35 USC § 103
11. 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.
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.
12. Claims 1-4 are rejected under 35 U.S.C. 103 as being unpatentable over Rao et al 2019 (US20190194628A1, published 06/27/2019), and further in view of Michen et al 2010 (J Appl Microbiol. 2010 Aug;109(2):388-397), Yi et al 2017 (Clin Exp Vaccine Res. 2017 Jan;6(1):4-14),
Kaufman et al 2015 (Nat Rev Drug Discov. 2015 Sep;14(9):642-62).
Claim 1: Rao et al 2019 (US20190194628A1) is in the art and teaches production of an Enterovirus C virus in cell culture, harvesting the virus, passing the harvested Enterovirus C virus produced by the cell through a depth filter to produce a first eluate, wherein the first eluate comprises the Enterovirus C virus; binding the first eluate to a cation exchange membrane to produce a first bound fraction, wherein the first bound fraction comprises the Enterovirus C virus; eluting the first bound fraction from the cation exchange membrane to produce a second eluate, wherein the second eluate comprises the Enterovirus C virus (See, Rao et al 2019, US20190194628A1, claim 10). Rao et al 2019 teaches instant claim 1 step (a) binding the enterovirus to a cation exchange stationary phase using a loading solution with a pH of about 3.5 to 6.0 by disclosing in some embodiments, … an Enterovirus C virus of the present disclosure (e.g., poliovirus S1, S2, or S3) is bound to a cation exchange membrane at a pH that ranges from about 4.5 to about 6.0 ((claim 11, step (iv)); In some embodiments, the eluate is bound to the cation exchange membrane at a pH that is greater than about any of the following pHs: 4.5, 5.0, or 5.5. That is, the eluate can be bound to the cation exchange membrane at a pH in a range of pHs having an upper limit of 6.0, 5.5, or 5.0 and an independently selected lower limit of 4.5, 5.0, or 5.5; wherein the lower limit is less than the upper limit (See, para [0160]).
Rao et al 2019 teaches in cation exchange chromatography, the negatively charged substrate or membrane attracts positively charged macromolecules. Once macromolecules are bound or loaded onto the substrate, they may be eluted in linear or stepwise fashion from the substrate in a manner dependent on their characteristics, thereby enacting a separation of differently charged molecules. This principle may be used to purify viruses from other macromolecules. Elution may be effected by varying pH or salt content of the mobile phase buffer. As demonstrated herein, particular loading and elution parameters such as pH and salt content have dramatic effects on yield and purity of Enterovirus C virus purification. A variety of suitable buffers are known in the art and described herein. Viral purification methods using ion exchange chromatography are also generally known (See, para [0158]). As demonstrated herein, the buffers and conditions used for cation exchange chromatography loading (e.g., binding to a cation exchange membrane) and elution greatly impact virus purity and yield. In some embodiments, an eluate containing an Enterovirus C virus of the present disclosure (e.g., poliovirus S1, S2, or S3) is bound to a cation exchange membrane to produce a bound fraction containing the virus (See, para [0159]). Suitable pH ranges for elution using each of these buffers are known in the art; generally, the pH of the buffer is between the pI of the molecule (e.g., an Enterovirus C virus) and the pKa of the charged groups on the stationary phase. For example, in some embodiments, a bound fraction containing an Enterovirus C virus of the present disclosure is eluted from a cation exchange membrane by adjusting the pH to about 8.0 (See, para [0161]).
Rao et al 2019 renders obvious claim 1 limitation step (b) by disclosing parameters on pH 5.7 for the elution solution (page 48, para [0443], Table O). Rao et al 2019, however does not disclose the claimed pH of elution solution of about 3.5 to 4.8.
Michen et al 2010 is in the art and teaches isoelectric points (IEP) of viruses and teaches most frequently the isoelectric point of viruses is measured in a band of 3.5 < IEP < 7 (See, abstract). The IEPs for species of enterovirus genus are recited in Table 1, notably Human coxsackievirus A 21 has IEP 6.1 and 4.8, Poliovirus PV-2 Sabin T2 has IEP 6.5 and 4.5, Enterovirus B Human echovirus 1 has IEP 4.0 (See, abstract, page 390-391 Table 1).
The pH values of the elution buffer taught by Rao et al 2019 were sufficient to render obvious to make a solution that had the desired properties for elution of an enterovirus of claim 1 with combined teachings of Rao et al 2019 on the principle of cation-exchange chromatography as recited supra and isoelectric point (IEP) values or range taught in a review Michen et al 2010 for viruses including enterovirus species (See, abstract, page 390-391 Table 1). Therefore, determining or adjusting concentration based on requirement for optimal performance of enterovirus binding or elution form cation-exchange resin would have been obvious to one of the ordinary skills prior to effective filing date of the claimed invention by adjusting pH and the pH optimization fall under routine laboratory process. See MPEP 2144.05, In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955), In re Geisler, 116 F.3d 1465, 43 USPQ2d 1362 (Fed. Cir. 1997); and Peterson, 315 F.3d at 1330, 65 USPQ2d at 1382.
Furthermore, according to section 2144.05 of the MPEP, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” See MPEP 2144.05, In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). See also Peterson, 315 F.3d at 1330, 65 USPQ2d at 1382 (“The normal desire of scientists or artisans to improve upon what is already generally known provides the motivation to determine where in a disclosed set of percentage ranges is the optimum combination of percentages”).
It would have been obvious to one of the ordinary skills in the art before the effective filing date of the claimed invention to modify the prior art teachings of Rao et al 2019 with the additional teachings of Michen et al 2010 as recited supra to arrive at the inventions of claim 1. One of the ordinary skills would have been motivated to develop a method of purification of enterovirus for obtaining a pure enterovirus preparation with a better yield over the applied prior arts teachings for efficiency; and commercial success to apply the method to purify enteroviruses to produce vaccine and oncolytic enterovirus for therapy (See, Yi et al 2017, and
Kaufman et al 2015). There would be a reasonable expectation of success given the applied prior art teachings in the art to render the claims obvious the claim 1 method as recited supra. This is analogous to some teaching, suggestion, or motivation in the prior art that would have led one of ordinary skill to modify the prior art reference or to combine prior art reference teachings to arrive at the claim 1 invention. See KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007) (see MPEP § 2143, example of rationales, A-G).
Claim 2: Rao et al 2019 (US20190194628A1) teaches the method of claim 1 as recited supra and further teaches added limitation of claim 2, wherein prior to step (a), the stationary phase is equilibrated with an equilibration solution by disclosing (See, para [0158]) ... Elution may be effected by varying pH or salt content of the mobile phase buffer. As demonstrated herein, particular loading and elution parameters such as pH and salt content have dramatic effects on yield and purity of Enterovirus C virus purification (See, para [0158]). (Also, see instant specification (See, page 9, lines 17-19 ... The term "equilibration solution" refers to a solution to equilibrate the stationary phase prior to loading the enterovirus on the stationary phase. The equilibration solution can comprise one or more of a salt and buffer, and optionally a surfactant...).
Claim 3. Rao et al 2019 (US20190194628A1) teaches the method of claim 1 as recited supra and further teaches added limitation of claim 3, further comprising step (i) of washing the stationary phase with one or more wash solutions after step (a) but prior to step (b) (See, Rao et al 2019 (US20190194628A1), Figure 23A wherein loading then washing and then elution occurs, See, page 48, para [0443] Table O).
Claim 4: Rao et al 2019 (US20190194628A1) teaches the method of claim 3 as recited supra and further teaches added limitation of instant claim 4, however, does not specifically teach step 4 limitation wherein step (i) comprises a wash step with a wash solution having a conductivity higher than the equilibration solution or loading solution. Rao et al 2019 teaches wherein conductivity can be varied (Figure 10 wherein the conductivity is checked and adjusted between each different cation exchange) and the loading solution conductivity is high (Figure 15C wherein loading ranges from 8-8.5 for the Mustangs experiments). Therefore, it would have been obvious to one skilled in the art to vary the conductivity by routine experimentation in order to ensure all impurities are removed from the stationary phase to arrive at the invention of claim 4.
The wash buffer solution conductivity taught by Rao et al 2019 were sufficient to render obvious to make a wash solution that had the desired properties of conductivity higher than the equilibration solution or loading solution for optimal purification of an enterovirus of claim 1 with combined teachings of Rao et al 2019 on the principle of cation-exchange chromatography as recited supra and isoelectric point (IEP) values or range taught in a review Michen et al 2010 for viruses including enterovirus species (See, abstract, page 390-391 Table 1). Therefore, determining or adjusting concentration (concentration reads on conductivity) based on requirement for optimal performance for washing steps removal of impurities bound to the cationic resin to which the enterovirus is bound would have been obvious to one of the ordinary skills prior to effective filing date of the claimed invention by adjusting the equilibration solution and further adjust conductivity of wash solution is an optimization of a method that fall under routine laboratory process. See MPEP 2144.05, In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955), In re Geisler, 116 F.3d 1465, 43 USPQ2d 1362 (Fed. Cir. 1997); and Peterson, 315 F.3d at 1330, 65 USPQ2d at 1382.
Furthermore, according to section 2144.05 of the MPEP, differences in concentration (concentration reads on conductivity) or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such conductivity or concentration or temperature is critical. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” See MPEP 2144.05, In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). See also Peterson, 315 F.3d at 1330, 65 USPQ2d at 1382 (“The normal desire of scientists or artisans to improve upon what is already generally known provides the motivation to determine where in a disclosed set of percentage ranges is the optimum combination of percentages”).
It would have been obvious to one of the ordinary skills in the art before the effective filing date of the claimed invention to modify the combined prior art teachings of Rao et al 2019, Michen et al 2010 as applied to claim 1 above with incorporating additional teachings of Rao et al 2019 to render obvious the added limitations to arrive at the inventions of claims 2-4. One of the ordinary skills would have been motivated to develop a method of purification of enterovirus for obtaining a pure enterovirus preparation with a better yield over the applied prior arts teachings for efficiency; and commercial success to apply the method to purify enteroviruses to produce vaccine and oncolytic enterovirus for therapy (See, Yi et al 2017, and
Kaufman et al 2015). There would be a reasonable expectation of success given the applied prior art teachings in the art to render the claims obvious the claims 2-4 method as recited supra. This is analogous to some teaching, suggestion, or motivation in the prior art that would have led one of ordinary skill to modify the prior art reference or to combine prior art reference teachings to arrive at the claims 2-4 inventions. See KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007) (see MPEP § 2143, example of rationales, A-G).
13. Claims 5-19 are rejected under 35 U.S.C. 103 as being unpatentable over combined teachings of Rao et al 2019 (US20190194628A1, published 06/27/2019), Michen et al 2010 (J Appl Microbiol. 2010 Aug;109(2):388-397), Yi et al 2017 (Clin Exp Vaccine Res. 2017 Jan;6(1):4-14), Kaufman et al 2015 (Nat Rev Drug Discov. 2015 Sep;14(9):642-62), and further in view of ThermoFisher Inc 2018 (Publication No. 100031321, 24 April 2018) and GE Healthcare Inc 2016 (Publication No. 11000421 AC 01/2016).
Claims 5-19: The combined teachings of Rao et al 2019 and Michen et al 2010 renders obvious claim 1 as recited supra and the prior art teachings as applied to claim 1 above are incorporated here in entirety.
Claims 5-11 (dependent on claim 1): Rao et al 2019 (US20190194628A1) teaches partially the added limitations of the instant claims 5-8, wherein one or more of the loading solution, equilibration solution, the one or more wash solutions and the elution solution has a pH of about 3.8-4.5 (instant claim 5); wherein the elution solution has a pH of about 3.8-4.5 (instant claim 6); wherein one or more of the loading solution, equilibration solution, the one or more wash solutions and the elution solution has a pH of about 4.0 (instant claim 7); wherein one or more of the loading solution, equilibration solution, the one or more wash solutions and the elution solution further comprises a surfactant (instant claim 8); wherein the surfactant is PS-80 or PS-20 (claim 9 a method of claim 1); wherein the surfactant is about 0.001-1% w/v PS- 80 (claim 10); wherein the surfactant is about 0.005 % w/v PS- 80 (claim 11).
Rao et al 2019 teaches added limitations of instant claims 5-11 by disclosing cation exchange chromatography for Enterovirus C virus purification and recites loading (loading buffer) and elution (elution buffer) parameters such as pH and salt content have dramatic effects on yield and purity of Enterovirus C virus (See, para [0158]-[0159]), first wash, and second wash steps (See, para [0406]). Rao et al 2019 teaches in some embodiments, an eluate containing an Enterovirus C virus of the present disclosure (e.g., poliovirus S1, S2, or S3) is bound (binding or loading buffer) to a cation exchange membrane at a pH that ranges from about 4.5 to about 6.0 (See, para [0160]). Rao et al 2019 teaches when harvesting the Enterovirus C virus produced by the cell by addition and treating the harvest from approximately one hour to approximately four hours results in the increased yield of Enterovirus C virus, as compared to a yield of Enterovirus C virus harvested in the absence of the surfactant (See, para [011], claim 1). Rao et al 2019 further teaches cation exchange chromatography parameters for binding, washing and elution, acidification (binding buffer) with pH 5.7 and 5; wash buffer pH 5.7 and 6.5, elution buffer pH 5.7 and 5 (See, page 48, col 2 Table O).
Rao et al 2019 teaches a variety of surfactants may be suitably used in a cell culture medium of the present disclosure, including without limitation polysorbates such as polysorbate 20 (also known as TWEEN® 20), 40, 60, and 80 (also known as TWEEN® 80) (See, para [0080]). In some embodiments, the amount of surfactant added to the cell culture medium ranges from 0.005% to 0.05% (e.g., as a v/v percentage of the volume of cell culture medium), such as 0.005%, 0.010%, 0.015%, 0.020%, 0.025%, 0.030%, 0.035%, 0.040%, 0.045%, or 0.050%, including any values therebetween. In certain embodiments, 0.05% polysorbate is added. In certain embodiments, 0.005% polysorbate is added (See, para [0080]). In some embodiments, a buffer used in cation exchange chromatography (e.g., in loading and/or elution) contains polysorbate (e.g., TWEEN®-80 at 0.05%, 0.1%, 0.25%, or 0.5%) (See, para [0159], para [0275], Example 6). Use of polysorbate caused a slight increase in capture efficiency (See, para [0387]). In another aspect, a higher (e.g., 5-fold higher) polysorbate concentration (e.g., TWEEN®-80 concentration) is used during chromatography loading, wash, and elution. For example, the following concentrations of polysorbate (e.g., TWEEN®-80) are tested: 0% (as a negative control), 0.05%, 0.1%, 0.25%, and 0.5% (See, para [0414]; claim 3, and claim 11- (iii)).
The instant claim 5 limitation, wherein one or more of the loading solution, equilibration solution, the one or more wash solutions and the elution solution has a pH of about 3.8-4.5, however, Rao et al 2019 teaches a binding or loading buffer pH of that ranges from about 4.5 to about 6.0 (See, para [0160]). The “about” definition (instant specification page 8, lines 13-22) allows variation of “± 10 %” and therefore Rao et al 2019 teaches a pH of 4.05.
Claims 12-18: Rao et al 2019 teaches and renders obvious added limitations of claims 12, wherein the loading solution (binding solution) or equilibration solution comprises about 50-500 mM monovalent salt (instant claim 12); added limitations of claims 13, wherein the loading solution (binding solution) or equilibration solution comprises up to about 350 mM monovalent salt (instant claim 13); added limitations of claims 14, wherein the one or more wash solutions comprises about 50-600 mM monovalent salt (instant claim 14); added limitations of claims 15, wherein the one or more wash solutions comprises about 400-600 mM NaCl or KCl (instant claim 15); added limitations of claims 16, wherein the elution solution comprises about 350-1200 mM of monovalent salt (instant claim 16); added limitations of claims 17, wherein the elution solution comprises about 200-1000 mM NaCl or KCl (instant claim 17); added limitations of claims 18, wherein the elution solution comprises about 550-850 mM NaCl or KCl (instant claim 18) by disclosing the NaCl concentration of wash buffer 100 and 150 mM, the NaCl concentration of elute buffer 250 and 300 mM (See, page 48, col 2 Table O). For pH loading onto cation exchange membrane, as shown in FIG. 28A, 100% of total virus (DU) was captured between pH 5.00 and 5.51. NaCl elution from cation exchange membrane was also examined using strain S3. Approximately 91.7% of virus was observed to elute at 200 mM to 300 mM NaCl (FIGS. 28B & 28C) (See, para [0435]). An elution buffer with NaCl 300 mM to 1000 mM (1M) gradient buffer elution is taught (See, Table F on page 46). Therefore, Rao et al 2019 teaches claims 12-18 limitations on the NaCl concentration in mM comprising buffers used for loading solution (binding solution) or equilibration solution, was and elution.
In addition, ThermoFisher Inc 2018, and GE Healthcare Inc 2016 are in the protein and virus purification and and provides teachings/ guidance to use as a starting point or optimize the parameters of binding, equilibration, wash and elution solution for pH and NaCl ionic strength for cation exchange chromatography (See, ThermoFisher Inc 2018, and GE Healthcare Inc 2016).
Recommended Equilibration buffer 100 mM NaCl, a pH use the same pH for load solution and equilibration buffer. Use a binding pH 1 to 3 units below the isolelectric point (pI) of the target molecule. Use the same starting pH for load solution and equilibration buffer, then optimize the pH of the elution buffer. Optimum binding and elution pH can differ based on target protein (virus) (See, ThermoFisher Inc 2018, page 1-8).
Claim 19: ThermoFisher Inc 2018 teaches instant claim 19 limitation, wherein the cation exchange stationary phase is PorosTm 50 HS by disclosing 50-µm, rigid, polymeric, ion-exchange chromatography resins that can be used for a cation exchange chromatography of biomolecules including viruses (See, page 1).
GE Healthcare Inc 2016 teaches principles of ion exchange chromatography including cation exchange chromatography for viruses, and teachings/ guidance to use as a starting point or optimize the parameters of binding, equilibration, wash and elution solution for pH and NaCl ionic strength for cation exchange chromatography (See, GE Healthcare Inc 2016, chapters 1-4 and appendix, page 121 Fig 4.7, see entire publication).
The pH values and NaCl (mM) concentrations for different buffers for the steps (binding, equilibration, wash and elution) of cation exchange chromatography taught by combined teachings of prior arts by Rao et al 2019, ThermoFisher Inc 2018, and GE Healthcare Inc 2016 along with teachings by Michen et al 2010 on isoelectric point for different species of enteroviruses were sufficient to render obvious to prepare and use the claimed buffer solution (claims 5-19) that had the desired properties for binding, equilibration, wash and elution of an enterovirus (claim 1 and interdependent claims) to practice the methods of claims 5-19 for purification of the enterovirus. Therefore, determining or adjusting concentration based on requirement for optimal performance of enterovirus binding, equilibration, wash and elution to practice the claimed method(s) of cation-exchange chromatography would have been obvious to one of the ordinary skills prior to effective filing date of the claimed invention by adjusting pH and NaCl ionic strength (mM) that optimization fall under routine laboratory process. See MPEP 2144.05, In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955), In re Geisler, 116 F.3d 1465, 43 USPQ2d 1362 (Fed. Cir. 1997); and Peterson, 315 F.3d at 1330, 65 USPQ2d at 1382.
Furthermore, according to section 2144.05 of the MPEP, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” See MPEP 2144.05, In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). See also Peterson, 315 F.3d at 1330, 65 USPQ2d at 1382 (“The normal desire of scientists or artisans to improve upon what is already generally known provides the motivation to determine where in a disclosed set of percentage ranges is the optimum combination of percentages”).
It would have been obvious to one of the ordinary skills in the art before the effective filing date of the claimed invention to modify the prior art teachings of Rao et al 2019 with the additional teachings of ThermoFisher Inc 2018, and GE Healthcare Inc 2016 along with teachings by Michen et al 2010 on isoelectric point for different species of enteroviruses as recited supra to arrive at the inventions of claims 5-19. One of the ordinary skills would have been motivated to develop a method or methods(s) of purification of enterovirus species within the genus enterovirus for obtaining the enterovirus with a high level of purity, a better yield over the applied prior arts teachings for improved efficiency of the modified methods; and commercial success to apply the method to purify enteroviruses to produce vaccine and oncolytic enterovirus for therapy (See, Yi et al 2017, and Kaufman et al 2015). There would be a reasonable expectation of success given the applied prior art teachings in the art to render the claims obvious the claim 5-19 methods as recited supra. This is analogous to some teaching, suggestion, or motivation in the prior art that would have led one of ordinary skill to modify the prior art reference or to combine prior art reference teachings to arrive at the claims 5-19 inventions. See KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007) (see MPEP § 2143, example of rationales, A-G).
14. Claim 20 is rejected under 35 U.S.C. 103 as being unpatentable over combined teachings of Rao et al 2019 (US20190194628A1, published 06/27/2019), Michen et al 2010 (J Appl Microbiol. 2010 Aug;109(2):388-397), Yi et al 2017 (Clin Exp Vaccine Res. 2017 Jan;6(1):4-14), Kaufman et al 2015 (Nat Rev Drug Discov. 2015 Sep;14(9):642-62), ThermoFisher Inc 2018 (Publication No. 100031321, 24 April 2018) and GE Healthcare Inc 2016 (Publication No. 11000421 AC 01/2016) and further in view of Segers et al 2016 (WO 2016012445A2, 01/28/2016).
Claim 20: The combined prior art teachings of Rao et al 2019, Michen et al 2010, ThermoFisher Inc 2018, and GE Healthcare Inc 2016 that rendered obvious claims 1-19 as recited supra are incorporated here in entirety. However, the combined prior art teachings as applied to claims 1-19 do not teach binding and elution of an enterovirus within the same pH range as for the instant claimed pH of about 3.5 to 4.7 recited in instant claim 20.
Segers et al 2016 (WO 2016012445A2) teaches a method of purifying a poliovirus (an enterovirus) from crude cell culture harvests using a detergent followed by a clarification. The clarified poliovirus particle (an enterovirus) comprising harvest (refereed as feed material = an enterovirus or poliovirus comprising supernatant intended for binding to the cation exchange resin on column) is adjusted to an acidic pH ranging from 4.4 to 5.6 (instant claimed pH of about 3.5 to 4.7). Subsequently, adjusted feed material is loaded to a cation exchange chromatography membrane adsorber where the virus selectively binds to the membrane. Virus particles are further purified from impurities in the following elution step by increasing the ionic strength of the elution buffer while maintaining the pH range constant between 4.4-5.6 (See, abstract, page 14 lines 24-35, claims 1-4).
The pH value of about 3.5 to 4.7 as claimed in instant claim 20 for the combined binding and elution step of cation exchange chromatography as taught by Segers et al 2016 and combined teachings of prior arts by Rao et al 2019, ThermoFisher Inc 2018, and GE Healthcare Inc 2016, and Michen et al 2010 for different species of enteroviruses were sufficient to render obvious to prepare and use the claimed buffer solution with a pH value of about 3.5 to 4.7 (claims 20) that had the desired properties for binding, and elution of an enterovirus (claim 20) to practice the methods of claims 20 for purification of the enterovirus. Therefore, determining or adjusting concentration based on requirement for optimal performance of enterovirus binding, and elution to practice the claimed method of cation-exchange chromatography would have been obvious to one of the ordinary skills prior to effective filing date of the claimed invention by adjusting pH and NaCl ionic strength (mM) that optimization fall under routine laboratory process. See MPEP 2144.05, In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955), In re Geisler, 116 F.3d 1465, 43 USPQ2d 1362 (Fed. Cir. 1997); and Peterson, 315 F.3d at 1330, 65 USPQ2d at 1382.
Furthermore, according to section 2144.05 of the MPEP, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” See MPEP 2144.05, In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). See also Peterson, 315 F.3d at 1330, 65 USPQ2d at 1382 (“The normal desire of scientists or artisans to improve upon what is already generally known provides the motivation to determine where in a disclosed set of percentage ranges is the optimum combination of percentages”).
It would have been obvious to one of the ordinary skills in the art before the effective filing date of the claimed invention to modify the combined prior art teachings of Rao et al 2019, ThermoFisher Inc 2018, GE Healthcare Inc 2016, Michen et al 2010 with additional teachings of Segers et al 2016 for cation exchange chromatography purification of different species of enteroviruses as recited supra to arrive at the inventions of claim 20. One of the ordinary skills would have been motivated to develop a method or methods(s) of purification of enterovirus species within the genus enterovirus for obtaining the enterovirus with a high level of purity, a better yield over the applied prior arts teachings for improved efficiency of the modified methods; and commercial success to apply the method to purify enteroviruses to produce vaccine and oncolytic enterovirus for therapy (See, Yi et al 2017, and Kaufman et al 2015). There would be a reasonable expectation of success given the applied prior art teachings in the art to render the claims obvious the claim 20 method as recited supra. This is analogous to some teaching, suggestion, or motivation in the prior art that would have led one of ordinary skill to modify the prior art reference or to combine prior art reference teachings to arrive at the claim 20 invention. See KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007) (see MPEP § 2143, example of rationales, A-G).
15. Relevant Prior Arts:
Heffron J, Mayer BK. Improved Virus Isoelectric Point Estimation by Exclusion of Known and Predicted Genome-Binding Regions. Appl Environ Microbiol. 2020 Nov 10;86(23):e01674-20.
Potgieter, Natasha, and Sandra van Wyngaardt. "An anti-coxsackie B1 monoclonal antibody suitable for affinity chromatography." South African journal of science 93.2 (1997).
Kielkopf CL, Bauer W, Urbatsch IL. Purification of Fusion Proteins by Affinity Chromatography on Glutathione Resin. Cold Spring Harb Protoc. 2020 Jun 1;2020(6):102202.
Kaufman HL, Kohlhapp FJ, Zloza A. Oncolytic viruses: a new class of immunotherapy drugs. Nat Rev Drug Discov. 2015 Sep;14(9):642-62. doi: 10.1038/nrd4663. Erratum in: Nat Rev Drug Discov. 2016 Aug 30;15(9):660.
Berry LJ, Au GG, Barry RD, Shafren DR. Potent oncolytic activity of human enteroviruses against human prostate cancer. Prostate. 2008 May 1;68(6):577-87. (Year: 2008)
Conclusion
16. No claim is allowed.
17. Any inquiry concerning this communication or earlier communications from the examiner should be directed to SAMADHAN J JADHAO whose telephone number is (703)756-1223. The examiner can normally be reached M-F 8:00-5:00.
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/SAMADHAN JAISING JADHAO/ Examiner, Art Unit 1672
/BENNETT M CELSA/ Primary Examiner , Art Unit 1600