DETAILED ACTION
Status of claim rejections
The rejection of record under 35 USC 103 is maintained and modified in view of Applicant’s amendments/arguments in the response field 12/17/25.
This Action is FINAL, as necessitated by Applicant’s amendments.
Information Disclosure Statement
The information disclosure statement(s) (IDS) submitted 12/17/2025 was properly filed in compliance with 37 CFR 1.97. Accordingly, the information disclosure statement(s) was considered.
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-2, 7-8, 11, 14-15, and 21-24 are rejected under 35 U.S.C. 103 as being unpatentable over Herigstad et al (US 8946395 B1, 03 February 2015; hereinafter “Herigstad”) in view of Breece (US 6870034 B2; 22 March 2005; prior art of record; hereinafter “Breece”), as evidenced by Jones et al (Biotechnology Bioengineering. August 2021. 118, 2870–2885; prior art of record; hereinafter “Jones”) and further in view of Singh et al (Effect of Polysorbate 20 and Polysorbate 80 on the Higher-Order Structure of a Monoclonal Antibody and Its Fab and Fc Fragments Probed Using 2D Nuclear Magnetic Resonance Spectroscopy. J Pharm Sci. 2017 Dec;106(12):3486-3498; hereinafter “Singh”).
Herigstad teaches methods for purifying a protein of interest, e.g., recombinant antibody, from a sample comprising the protein of interest and at least one impurity (abstract), comprising (a) contacting a sample comprising the protein of interest and at least one impurity (a sample comprising protein of interest and at least one impurity as in claims 1-2, step (a) in part), to a hydrophobic interaction chromatography (HIC) media, in the presence of a load buffer; such that (i) a portion of the protein of interest binds to the HIC media at a Kp of greater than 20 and (ii) a substantial portion of the at least one impurity binds to the HIC media; (b) collecting a flow through fraction comprising the protein of interest unbound to the HIC media recovering the protein from the chromatography material as in claims 1-2, step (c)); (c) washing the HIC media with a wash buffer such that a substantial portion of the protein of interest bound to the HIC media is released from the media, wherein the salt concentration and/or the pH of the wash buffer are within 20% of the salt concentration and/or pH of the load buffer; and (d) collecting a wash fraction comprising the protein of interest released from the HIC media, wherein each of the flow through and wash fractions comprise the protein of interest and have a reduced level of the at least one impurity (see claim 1). Herigstad also teaches that the impurity is a host cell protein, nucleic acid, media component, or chromatographic material (see claim 13, col 5, lines 52-53). Herigstad also teaches that the load buffer is a salt solution that is passed through the HIC media simultaneously or substantially simultaneously with the sample, and specifically that the load buffer is combined with the sample prior to passage through the HIC media (applying the mixture of step (a) to a chromatography material as in claims 1-2, step (b), in part) (col 21, lines 15-20). Herigstad further teaches that the antibodies used in the purification method can be antibodies expressed in Chinese Hamster Ovary cells (CHO cells) (col 46, lines 9-14).
Herigstad does not explicitly teach the addition of polysorbate to the sample containing the protein (as in claim 1-2, step (a) in part) prior to the chromatography step.
However, Breece teaches purification of proteins using protein A chromatography (i.e., affinity chromatography as in claim 1) using wash buffers (abstract). Breece also teaches the purification of antibodies by removing contaminants by washing the solid phase with a composition comprising detergent and salt at about pH 4.5 to about 5.5 (col 2, lines 20-55; col 25, claim 1), where the detergent is a polysorbate, specifically polysorbate 20 (TweenTM 20) and polysorbate 80 (TweenTM 80) (col 4, lines 61-63; col 17, lines 31-34). Breece also teaches that an increase in polysorbate concentration in the intermediate wash buffer decreased the amount of CHO protein (CHOP) contaminants (see Example 2, col 19, and Fig. 8). Breece further teaches that polysorbate and a salt showed good CHOP clearance and yield of the purified protein (col 20).
Therefore, it would have been prima facie obvious to one of ordinary skill at the time of filing to modify the method of Herigstad with the polysorbate solution as taught by Breece to arrive at the claimed invention. As the claimed invention relies on the purification of proteins/removal of impurities using polysorbate solution, one of ordinary skill would have been motivated to perform a simple substitution of one known element (the loading buffer salt solution of Herigstad) with another (the polysorbate salt solution of Breece) with a reasonable expectation of success (purification of proteins using polysorbate). One of ordinary skill would have been motivated to make the substitution because Breece teaches that that an increase in polysorbate concentration in the intermediate wash buffer advantageously decreased the amount of CHO protein (CHOP) contaminants (see Example 2, col 19, and Fig. 8) and polysorbate and a salt shows good CHOP clearance and yield of the purified protein (col 20).
One of ordinary skill would also have been motivated to perform a simple substitution of one known element (the HIC media of Herigstad) with another (the affinity chromatography material of Breece) with a reasonable expectation of successful purification of proteins using polysorbate on affinity chromatography material for the same reasons as set forth above.
Neither Herigstad nor Breece explicitly teach the sample has at least one impurity with hydrolytic activity (as in claim 1-2). However, as evidenced by Jones, the CHO expression system has various host cell proteins (HCPs) that can be found and processed during Protein A affinity purification followed by additional polishing steps to remove aggregates, charge variants, HCPs, and host cell DNA (pg. 2871, col 2, paragraph 2). The HCPs commonly found during purification include proteins such as lipoprotein lipase (LPL) (at least one impurity with hydrolytic activity as in claim 1; lipase impurity as in claim 1), liver carboxylesterase and sialate o-acetylesterase (pg. 2872-2874, Table 1; esterase as impurity as in claim 1 and 2). Thus, absent evidence to the contrary, the impurities with hydrolytic activity, lipase, and esterase would be inherently present in the CHO host cell protein contaminants of Herigstad/Breece, as Jones evidences common CHO HCP proteins seen during processing.
Hergistad teaches various incubation steps with samples (see, e.g., Fig. 13; col 26, lines 15-27; col 41, lines 20-35), but does not explicitly teach incubating the resulting sample after adding the polysorbate to the sample.
However, Singh teaches the effect of polysorbates on structures of monoclonal antibodies (see title and abstract). Singh explicitly teaches using size exclusion chromatography where 20 mg/mL of protein samples were incubated with and without polysorbates (PS80 or PS20) for 20 hours (pg. 4). Singh teaches that incubation of the samples resulted in increased protection of the antibodies against aggregation (pg. 5), where PS80 is preferred because it offers higher protection against aggregation, causes less structural perturbations, and has weaker binding site affinity than PS20 (see pg. 13-14).
Therefore, it would have been prima facie obvious to one of ordinary skill at the time of filing to modify the method of Hergistad and Breece by incubating the protein sample with polysorbates before chromatography purification to arrive at the claimed invention. One of ordinary skill would have been motivated to make the modification because Singh explicitly teaches that polysorbates like PS80 advantageously offers higher protection of the protein sample against aggregation, and causes less structural perturbations in the protein.
Regarding claim 7-8, Breece teaches using polysorbate in concentrations from about 0.01 to about 5% (col 4, lines 61-63; col 17, lines 31-34).
Regarding claim 11, Breece uses Protein A chromatography, an affinity chromatography material (see claim 1; throughout entire document).
Regarding claims 14-15, Herigstad and Breece both teach purifying monoclonal antibodies (see col 42, lines 32-50; Example 8 of Herigstad; see col 2, lines 56-62; col 3, lines 1-22; FIG. 5; col 25, claims 4-7 of Breece) and Breece also teaches that the protein to be purified can be anti-HER2 (col 2, lines 56-62; col 3, lines 1-22; FIG. 5; col 25, claims 4-7).
Regarding claims 21-22, Singh teaches incubating the sample for 20 hours (i.e., at least 12 hours as claimed).
Regarding claim 23-24, Singh does not explicitly teach incubating for 24 hours. However, it would have been prima facie obvious to one of ordinary skill to incubate for 24 hours because Singh teaches incubating for at least 20 hours and that the incubation step advantageously reduces protein aggregation in the sample.
Accordingly, the claimed invention was prima facie obvious to one of ordinary skill at the time of filing, especially in the absence of evidence to the contrary.
Second rejection
Claims 25-26 are rejected under 35 U.S.C. 103 as being unpatentable over Herigstad, as evidenced by Jones, and Singh as applied to claims 1-2, 7-8, 11, 14-15, and 21-24, and further in view of Mahajan et al (WO2015035180A1; published 03/12/2015; hereinafter “Mahajan”).
As discussed above, claims 1-2, 7-8, 11, 14-15, and 21-24 were rendered prima facie obvious by the teachings of Herigstad and Singh.
None of the references explicitly teaches in step ii)c), the solution comprising the polysorbate is added to the chromatography material and held for at least 30 mins.
However, Mahajan (in a similar field of endeavor of chromatography) teaches methods of cleaning and regenerating chromatography material (see abstract, title, and claim 1-2). Specifically, Mahajan teaches static hold protocols during purification of antibodies where buffers are passed through the chromatography material and held for at least 30 mins (see claims). Singh teaches that static holds allowed for extra residence time without using extra buffer, aides with mass transfer, and effectively serves to extract any remaining protein on the column into the buffer (para 0294). Singh also teaches that during purification of IgG antibodies, static holds effectively increased the amount of intact IgG washed off the column 5-fold after an elution buffer static hold (see para 300).
Therefore, it would have been prima facie obvious to one of ordinary skill at the time of filing to modify the method of Herigstad and Singh by including the static hold step during purification as taught by Mahajan to arrive at the claimed invention. One of ordinary skill would have been motivated to include a static hold step because Mahajan explicitly teaches that static holds allowed for extra residence time without using extra buffer, aides with mass transfer, and effectively serves to extract any remaining protein on the column into the buffer, and increased the amount of intact IgG washed off the column.
Accordingly, the claimed invention was prima facie obvious to one of ordinary skill at the time of filing, especially in the absence of evidence to the contrary.
Response to Arguments
Applicant's arguments filed 12/17/2025 have been fully considered but they are not persuasive.
On pg. 6-8 of the Remarks, Applicant argues the newly added limitation regarding incubation time is not taught by Herigstad and that this feature provides further benefits beyond what is reasonably expected from the cited art. Applicant points to the filed Declaration (given its fullest consideration) and argues that Herigstad is restricted to the simultaneous passage of the sample through the HIC media, does not mention necessity of incubation times, and that Applicant’s application shows that adding PS20 during washing results in decreased hydrolytic activity (see paragraph 3 of the declaration). Applicant also argues a person of ordinary skill would have to be motivated to combine Herigstad (relating to HIC) and add an optional component (polysorbate) of an intermediate wash solution taught by Breece (which relates to Protein A). Applicant argues that the skilled person would have to expect that the compositions for load buffer and intermediate wash solutions are interchangeable and using components taught for different chromatography materials are interchangeable. Applicant also argues that the resulting process of modifying Heirgstad with Breece would be one that utilizes HIC as the chromatography material.
In response, the examiner disagrees. First, while Herigstad is drawn to the use of HIC media and Breece is drawn to use of Protein A chromatography (an affinity chromatography material), it is important to note that both Herigstad and Breece both teach (respectively) that the materials are useful for the same purpose of successful purification of proteins using polysorbate and removal of impurities such as host cell and CHOP impurities (see claim 13, col 5, lines 52-53 of Herigstad and Example 2, col 19, and Fig. 8 of Breece). Thus, there is a reasonable expectation of success regarding substitution of HIC chromatography material of Herigstad with affinity chromatography material of Breece. Second, neither Breece nor Herigstad are required to teach the specific incubation times, as this was taught by newly cited Singh reference (see above).
Third, regarding Applicant’s argument regarding use of the load buffer of Herigstad vs the intermediate wash buffer of Breece, Breece explicitly teaches that having increase in polysorbate concentration in the intermediate wash buffer (i.e., a wash buffer as argued by Applicant) successfully decreased the amount of CHO protein (CHOP) contaminants when the buffer is added to the material (see above). Thus, one of ordinary skill would have been motivated to perform a simple substitution of one known element (the loading buffer salt solution of Herigstad) with another (the polysorbate salt solution of Breece) with a reasonable expectation of success (purification of proteins using polysorbate). One of ordinary skill would have been motivated to make the substitution because Breece teaches that that an increase in polysorbate concentration in the intermediate wash buffer advantageously decreased the amount of CHO protein (CHOP) contaminants (see Example 2, col 19, and Fig. 8) and polysorbate and a salt shows good CHOP clearance and yield of the purified protein (col 20).
On pg. 8-9, Applicant argues that Jones (evidentiary reference cited above) teaches that HCPs (a genus) encompasses certain esterases and lipases (species). Applicant argues that Jones does not teach all HCP compositions must comprise these species and at most a PHOSITA would conclude that the lipase and esterase may be present which is not sufficient for inherency. Applicant argues that the PHOSITA could not conclude that all permutations and combinations of elements taught in Breece and Herigstad would result in purification to effectively remove lipases and esterases. Applicant further points to the Maier reference (discussed in the Declaration and given fullest consideration) that Applicant argues because Maier discussed that binding behavior of PS degrading hydrolases have significant variation among individual molecules with no discernable trends this “implies specific tailoring of the chromatographic conditions is required for effective removal of individual PS degrading hydrolases and . . . impurities can persist even through chromatography steps.”
In response, the examiner disagrees. As discussed above, Breece and Herigstad teach removal of host cell impurities during chromatography, with Breece providing the specific teaching regarding use of polysorbates to do so. Jones, evidences that the CHO expression system has various host cell proteins (HCPs) that can be found and processed during Protein A affinity purification followed by additional polishing steps to remove aggregates, charge variants, HCPs, and host cell DNA (pg. 2871, col 2, paragraph 2). The HCPs commonly found during purification include proteins such as lipoprotein lipase (LPL) (at least one impurity with hydrolytic activity as in claim 1; lipase impurity as in claim 1), liver carboxylesterase and sialate o-acetylesterase (pg. 2872-2874, Table 1; esterase as impurity as in claim 1 and 2). The claims as argued, only require the removal of an esterase or a lipase (generally). Thus, the teachings of Jones that the specific species of LPL and carboxyl/acetylesterase that are commonly known HCP contaminants would be readily encompassed by the instant claims. Thus, absent evidence to the contrary, these contaminants would be inherently present in the CHO host cell protein contaminants of Herigstad/Breece, as Jones evidences common CHO HCP proteins seen during processing. As such, the rejections are maintained as set forth above.
Conclusion
NO CLAIMS ALLOWED.
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/G.C.R./Examiner, Art Unit 1651
/THOMAS J. VISONE/Supervisory Patent Examiner, Art Unit 1672