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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 25, 2026 has been entered.
DETAILED ACTION
The instant application is a CON of PCT/IB20/50581, filed January 24, 2020 with provisional application 62/796159, filed January 24, 2019. Applicant’s amendment filed June 25, 2026 is acknowledged. Claims 1-68, 70-73, and 81 are canceled, and claims 69 and 88 are amended. Currently claims 69, 74-80, and 82-88 are pending, wherein claims 82-87 are withdrawn. Claims 69, 74-80, and 88 are under examination.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 69, 74-80 and 88 are rejected under 35 U.S.C. 103 as being unpatentable over Ross et al. (Journal of Biotechnology 162 (2012) 262-273, cited in IDS filed 4/23/2025, hereinafter “Ross”) in view of Balasubramanian et al. (Journal of Biotechnology 200 (2015) 61–69, cited in IDS filed 5/12/2023, hereinafter “Bala”) and Block et al. (WO 2018/107079 A1, cited in PTO-892 mailed 10/2/2025, hereinafter “Block”), as evidenced by Yoshida et al. (Biochemical Genetics, Vol. 16, Nos. 7/8, 1978, hereinafter “Yoshida”), Chin et al. (BMC Biotechnology (2015) 15:44, pgs. 1-15, cited in PTO-892 mailed 3/26/2026, hereinafter “Chin”), GE Healthcare/HyClone Laboratories (ActiPro™ medium and Cell Boost™ supplements: benchmarking, scalability, and protein production in CHO cell culture. 2015, cytiva.com, cited in PTO-892 mailed 6/13/2024) and Pan et al. (Cytotechnology (2017) 69:39–56, cited in PTO-892 mailed 6/13/2024, hereinafter “Pan”).
Regarding claims 69, 74-75, and 88, Ross teaches production of alpha-1-antitrypsin (AAT) in PER.C6 cells, wherein the cells co-express AAT (codon optimized to express the "M1-type" allele, based on sequence from GenBank Acc. No. X01683) and α-2,3-sialyltransferase, resulting in identifying subclones that expressed over 2.5 g/L of the recombinant AAT (abstract). Ross teaches the cell culture production method included the PER.C6 cells transfected with plasmid expressing the recombinant AAT and α-2,3-sialyltransferase, seeded in fed-batch cultures, tested for potency, and then single cell clones were isolated and cultured to promote cell-growth for cell cloning (pg. 263, sec. 2.1). At several points during this expansion process, aliquots of cell supernatant were assayed for productivities, and the best expressing clones with the most desired glycosylation patterns were selected for the next round of expansion; those with poor characteristics were eliminated (pg. 263, sec. 2.1).
Ross teaches quantification of the sialic acid using equal 200 µg quantities of A1P1 and determines the nmolar amount of sialic acid released, with plasma derived A1P1 as the 100% control (pgs. 263-264, sec. 2.2.4.). Ross demonstrates that recombinant A1P1 produced with ST3 co-expression possesses approximately 90-95% of the total sialic acid content of plasma derived A1P1 (pg. 266 Fig. 2E). Although Ross does not explicitly disclose that the recombinant A1P1 comprises greater than 3.5 moles of sialic acid per more of AAT, Yoshida discloses plasma-derived human AAT contains approximately 6-8 moles of sialic acid per mole of AAT (pg. 644, Table 1). Therefore, considering the quantitative sialic acid content taught by Yoshida, Ross’s teaching that ST3 co-expression produces recombinant A1P1 having approximately 90-95% of sialic acid content derived A1P1, the recombinant A1P1 inherently possesses greater than 3.5 moles of sialic acid per mole of AAT.
Ross does not teach the AAT is co-transfected with a cut-and-paste transposase in a CHO cell line. As evidenced by Chin, codon-optimized human AAT in Chinese Hamster Ovary (CHO) lines are well-known and routine in the art (pg. 3, col. 1, para 2).
However, Bala teaches rapid recombinant protein production from piggyBac (PB) transposon-mediated stable CHO cell pools, which meets the limitations in claim 69 (title). Bala teaches the PB transposon system has been used to generate stable CHO cell lines at a significantly higher frequency and with higher volumetric recombinant protein productivity than by conventional plasmid transfection (pg. 62, col. 1, para 2). Bala teaches a human tumor necrosis factor receptor (TNFR) fused to a human IgG1 Fc were integrated into a plasmid with codon-optimized PBase gene and cells were transfected with the plasmid (pg. 63, sec. 2.2-2.3). Bala teaches the co-transfected cells were maintained in ProCHO5 media at 37 ⁰C until day 4, and then the temperature was changed to 31 ⁰C, resulting in protein yields of 0.6-0.8 g/L (pg. 63, sec. 2.7, pg. 66, col. 2, para 1).
Neither Ross nor Bala teach the culturing step is decreased at day 3 or day 5, nor that the process produces a titer of 3 g/L or greater.
However, Block teaches optimized methods for producing biologically active proteins, specifically in manufacturing GL-2045 (a Fc multimer) (abstract, [0006]). Block teaches CHO cells were co-transfected with an expression vector encoding GL-2045 and a piggyBac transposase [0011]. Block teaches the transfected cells were cultured at a first temperature of 37 ⁰C with ActiCHO P media, and then a temperature shift at day 3 or 4 occurs at 34 ⁰C, which meets the limitations of claims 69, 74-75, and 88 [0097]. Block teaches in some embodiments, a third temperature shift employed at 31⁰C [0097], which meets the limitations in claims 69 and 88. Block teaches the timing of the temperature shift is surprisingly most successful when viable cell density is in a logarithmic growth phase, generally when the viable cell density is 10 - 15 million cells/mL, generally corresponding to day 4-5 of bioreactor culture depending on initial seeding density [0206]. Block teaches the protein yield when the temperature is shifted to 32.5 ⁰C and 31 ⁰C on day 5 resulted in 7.2 g/L and 5.1 g/L, respectively ([00207, Table 11), which meets the limitation in claims 69 and 88.
Therefore, it would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to utilize the method of co-transfecting a eukaryotic host cell with AAT and another expression promoting gene, screening the highest producing clone and culturing for high protein production as taught by Ross, and modify Ross’s method by using a CHO host cell co-transfected with the AAT and a piggyBac transposon, wherein the temperature is decreased between days 3-5 as taught by Bala and Block with a reasonable expectation of success. One of ordinary skill in the art would have been motivated to utilize the piggyBac transposon system to rapidly produce recombinant AAT in CHO cells to advantageously isolate high numbers of AAT protein from the cell culture, as taught by Bala. Further it would have been advantageous to modify the cell culture method by decreasing the temperature at day 3 or 5 to effectively produce high titers of greater than 3 g/L as taught by Block with a reasonable expectation of success.
Regarding claims 76-80, neither Ross nor Bala teach the cell culture methods comprised at least one feed, either neutral or alkaline in the specific concentrations recited in claims 76-79.
However, Block teaches the evaluation of several media feeds for CHO culture methods, and found ActiCHO Feed A and Feed B enhanced cell culture productivities, resulting in substantially higher titers than any other feeds [00200]. Block teaches the Power Feed A was inoculated into the culture at 4% and the Power Feed B was fed into the culture at 0.4%, which falls within the ranges recited in claims 77 and 79 (pg. 108, Fig. 13A). As evidenced by the product specification by GE Healthcare, ActiCHO Feed -A and -B are the same as Cell Boost 7a and 7b, and are dosed similarly at 3% and 0.3% respectively (Materials and Methods), which is defined in the instant specification as Cell Boost 7a being the neutral feed and Cell Boost 7b being the alkaline feed recited in claims 76 and 78.
Block is silent on the osmolarity of the cell culture, specifically being greater than 550 mOsm/kg. However, as evidenced by Pan, the similar feeding schedules of ActiCHO Feed A and B resulted in an increase up to 620 mOsm/kg for a CHO clone, which inherently meets the limitation of claim 80 (pg. 45, col. 2, para 1).
Therefore, it would have been prima facie obvious to one of ordinary skill in the art at the time of filing to modify the methods of introducing AAT and a piggyBac transposase into a CHO taught by Ross and Bala, wherein the culture method further comprises adding a neutral and alkaline feed at the specific concentrations as taught by Block with a reasonable expectation of success. One of ordinary skill in the art would have been motivated to add these two commercially available feeds for optimal CHO growth and protein production, since these two feeds promote an increase in reliably higher protein production titers as taught by Block.
Response to Arguments
Applicant's arguments filed June 25, 2026 have been fully considered but they are not persuasive.
Regarding Remarks directed to the 35 USC § 103 rejection, Applicant argues Ross does not teach or suggest produced human recombinant AAT protein "comprises greater than 3.5 moles of sialic acid per mole of AAT” and does not provide the required motivation or reasonable expectation of success for the claimed CHO process with this quantitative sialic acid limitation. Ross explains that natural sialylation of PER.C6-produced recombinant proteins reflects underrepresentation of sialyltransferases, and that this was compensated by co-transfection of human AAT cDNA with a recombinant human sialyltransferase gene. See, e.g., Ross at p. 263, left col., 1. Applicant argues in addition to using a different host-cell system, PER.C6, Ross also uses a different glycosylation strategy, i.e., co-expression of recombinant AAT with human a-2,3- sialyltransferase, followed by screening for clones with desired glycosylation patterns. Ross's teaching is not that any high-expression mammalian system would predictably produce highly sialylated AAT, but rather that Ross addressed sialylation in its selected PER.C6 system through dedicated sialyltransferase co-expression and clone screening. Applicant argues Ross does not provide motivation or guidance for a POSA to replace PER.C6/ST3 system with a CHO/cut-and-paste transposase system, much less provide a reasonable expectation that the resulting CHO-derived AAT would comprise greater than 3.5 moles of sialic acid per mole of AAT. Applicant also argues the relative measurements do not disclose an absolute mole-per-mole sialic acid content for any recombinant AAT sample. Moreover, an attempt to convert Ross's FIG. 2E percentages into moles of sialic acid per mole of AAT would require importing an unstated absolute value for Ross's plasma-derived AlPI control. Ross itself does not provide that value and therefore does not disclose that any recombinant AAT sample, much less CHO-produced recombinant AAT, comprises greater than 3.5 moles of sialic acid per mole of AAT. Applicant argues neither Bala nor Block describes AAT-specific sialylation or any sialic acid content for recombinant AAT, let alone CHO-produced recombinant AAT having greater than 3.5 moles of sialic acid per mole of AAT. They also fail to provide a reason why their non-AAT CHO productivity teachings would be expected to generate the claimed AAT product- quality attribute. Moreover, although Chin shows that CHO cells can express recombinant human AAT and suggests that the CHO-produced AAT is glycosylated based on apparent molecular weight, Chin fails to describe any sialic acid content, let alone greater than 3.5 moles of sialic acid per mole of AAT. GE and Pan provide feed and osmolality context for CHO culture; they likewise do not disclose or suggest the claimed AAT-specific mole-per-mole sialic acid content. Applicant argues the cited art lacks an articulated reason why a POSA would have modified Ross's PER.C6/a-2,3-sialyltransferase AAT system with Bala's and Block's CHO/piggyBac teachings for different proteins and reasonably have expected the resulting CHO-based AAT process to produce recombinant AAT having greater than 3.5 moles of sialic acid per mole of AAT. At most, the cited combination would have suggested that AAT sialylation is important and that sialylation may require host- and process-specific engineering and screening, thus do not render the claimed methods obvious.
In response to applicant’s argument that there is no teaching, suggestion, or motivation to combine the references, the examiner recognizes that obviousness may be established by combining or modifying the teachings of the prior art to produce the claimed invention where there is some teaching, suggestion, or motivation to do so found either in the references themselves or in the knowledge generally available to one of ordinary skill in the art. See In re Fine, 837 F.2d 1071, 5 USPQ2d 1596 (Fed. Cir. 1988), In re Jones, 958 F.2d 347, 21 USPQ2d 1941 (Fed. Cir. 1992), and KSR International Co. v. Teleflex, Inc., 550 U.S. 398, 82 USPQ2d 1385 (2007). In this case, Ross teaches a system for producing recombinant AAT with high sialyation production, albeit the system is not exactly the same as the Applicant’s, even though Chin discloses CHO cell systems are commonly utilized for producing recombinant AAT. Bala and Block teach co-transfected CHO cell lines with piggyBac transposase aiding in the production of fusion proteins and a Fc multimer, respectively. Both Bala and Block teach the temperature timings and feeds to enhance protein production in the clonal CHO cell lines to produce high protein titers (7.2 g/L for Block). As evidenced by the new reference Yoshida, it is well-known in the art that plasma-derived human AAT already possesses 6-8 moles of sialic acid per AAT, therefore, the fact that the inventor has recognized another advantage (i.e. using a highly productive CHO cell line utilizing culture methods to increase production), which would flow naturally from following the suggestion of the prior art cannot be the basis for patentability when the differences would otherwise be obvious. See Ex parte Obiaya, 227 USPQ 58, 60 (Bd. Pat. App. & Inter. 1985). Thus, it would be prima facie obvious to one of ordinary skill in the art to take the teachings of selecting a high producing clone that has been transformed to produce AAT as taught by Ross, utilize a common transformation technique such as co-transfecting with piggyBac transposase as taught by Bala, and optimize the CHO cell culture methods by decreasing the temperature at days 3 or 5 to enhance the cell productivities as taught by Block with a reasonable expectation of success.
Conclusion
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/LOUISE W HUMPHREY/Supervisory Patent Examiner, Art Unit 1657
/JESSICA EDWARDS/
Examiner, Art Unit 1657
