DETAILED ACTION
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 .
Priority
The application claims priority to provisional applications 63229654, filed on 05 August 2021, and 63305236, filed on 31 January 2022, and is a 371 of PCT/US2022/074507, filed on 04 August 2022. The effective filing date is 05 August 2021.
Information Disclosure Statement
The information disclosure statement (IDS), filed on 01 June 2024, was considered by the examiner.
Status of Application, Amendments, and/or Claims
Claims 1-17 are the original claims. In the amendment of 02 February 2024, claims 3, 8, 10, 11, and 15 were amended, and claims 18-20 were added. Claims 1-20 are pending and the subject of this office action.
Claim Rejections - 35 USC § 112
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 1 and 2 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 claims comprise a limitation requiring the referenced monoclonal cell lines be cultured under optimized culture conditions. The referenced claims as well as the specification fail to define what qualifies as “optimized culture conditions”. For the purpose of the office action, the examiner is interpreting the claim limitation to refer to culture conditions optimized for cell growth and protein production.
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.
Claims 1-5, 10-13, 15, 16, 18, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Brand HN, et al. (1994) Selection strategies for highly productive recombinant cell lines. Animal Cell Technology: Products of Today, Prospects for Tomorrow. (1994-01-01) Pages 55-60, Butterworth-Heinemann Ltd., XP055977490 (herein Brand), which is listed in the IDS of the current application.
Brand et al relates to an investigation of specific production rate (SPR) differences between six closely related recombinant CHO cell lines (Abstract). Brand establishes that the productivity of a cell line selected for the manufacture of a biopharmaceutical has a major influence on economics of the production the product (Introduction). It is also taught that the dominant selection parameter for suspension batch culture is product concentration. In order to investigate previously observed decreases in the SPR of hybridoma and recombinant cell lines, the authors compared six different CHO cell lines/clones, in triplicate, under suspension and static conditions (Results: The productivity of recombinant CHO cell lines in attached and suspension culture). The first three cell lines were cloned, following an initial transfection, and an additional three were re-cloned from one of the first cell lines, following exposure to medium, comprising increased methionine sulphoximine concentration (Results and Discussion). It is shown that significant differences in SPR were observed between clones, under different culture conditions (adherent or suspension). The authors note that differences in SPR were observed between the three re-cloned cell lines, which indicated that the differences in SPR were not a feature of a particular vector integration event (Results: The productivity of recombinant CHO cell lines in attached and suspension culture and Figure 1). This implies that differences in the SPR of the three re-clones, as well as their parent clone, are the result of increased exposure to the selective agent.
Based on these teachings the limitations, established in claims 1 and 2, would have been obvious to one skilled in the art, at the time of filing, as detailed below:
culturing a monoclonal cell line under optimized culture conditions;
The applicant has provided no definition for the term “optimized culture conditions”, as a result the examiner is interpreting this term using the broadest reasonable interpretation (e.g. conditions optimized for cell growth and protein production). Culturing a monoclonal cell line under optimized culture conditions would have been obvious to one skilled in the art, as it is well known in the art that the composition of culture conditions can greatly influence the production of recombinant material. Furthermore, Brand teaches conditions serum-free suspension conditions and static conditions, supplemented with serum, both of which are shown to be effective for the disclosed method (Introduction-paragraph 2). Further optimization of these conditions would have been obvious following routine experimentation, see MPEP 2144.05 IIa.
re-cloning the single cell of the monoclonal cell line;
Brand teaches a method, in which a monoclonal cell line is re-cloned. In the context of the referenced study, the re-cloning was performed as a control for vector integration, but the use of this step for optimizing SPR would have been obvious to one skilled in the art, based on the results shown in Figure 1. Figure 1 shows that, following a re-cloning step, A2 (a re-clone of clone A) showed a significant increase in SPR relative to its parental clone. This finding renders the inclusion of this re-cloning step to be obvious, as it demonstrates a means of improving SPR (product concentration), which Brand teaches to be a dominant selection parameter.
selecting the re-cloned cells with higher titer;
Brand teaches that the dominant selection parameter for suspension batch culture is product concentration. Therefore, it would have been obvious to select the clone with the highest product concentration to apply to subsequent culturing steps.
culturing the selected re-cloned cell, thereby producing the recombinant polypeptide of interest;
Brand teaches that the re-cloned cell lines are cultured in both adherent/attached and suspension culture. The SPR of these cultured cells are used in a measured then used in a comparison, which implies that the protein of interest is produced (Figure 1).
In regard to claims 3-5, and 18, Brand teaches a method that comprises the limitations of claims 1 and 2, as discussed above.
Brand also teaches that the re-cloned cell lines are re-cloned after gene amplification, comprising “increasing the concentration of the glutamine synthetase inhibitor, methionine sulphoximine, in the medium” (Results: The productivity of recombinant CHO cell lines in attached and suspension culture). This statement teaches that MSX was used as the selection agent, and that in the re-cloning procedure increased levels of MSX were used, which implies its use in the production of the initial clone.
In regard to claims 11-13, Brand teaches a method that comprises the limitations of claims 1 and 2, as discussed above.
Brand’s method is demonstrated using CHO cell lines, a mammalian cell line (Results and Discussion).
In regard to claims 15 and 16, Brand teaches a method that comprises the limitations of claims 1 and 2, as discussed above.
Brand’s method is demonstrated using CHO cell lines, producing a recombinant antibody (Results and Discussion).
Claims 6-9, 17, and 19 are rejected under 35 U.S.C. 103 as being unpatentable over Brand HN, et al. (1994) Selection strategies for highly productive recombinant cell lines. Animal Cell Technology: Products of Today, Prospects for Tomorrow. (1994-01-01) Pages 55-60, Butterworth-Heinemann Ltd., XP055977490 (herein Brand) in view of Tian J, et al. (2020) Increased MSX level improves biological productivity and production stability in multiple recombinant GS CHO cell lines. Eng Life Sci. 2020 Jan 9;20(3-4):112-125 (herein Tian), first published on 09 January 2020 with Golay J, et al. (2020) Combined Anti-Cancer Strategies Based on Anti-Checkpoint Inhibitor Antibodies. Antibodies (Basel). 2020 May 20;9(2):17 (herein Golay) providing additional evidentiary value.
In regard to claims 6 and 7, Brand teaches a method of producing a recombinant polypeptide of interest, comprising re-cloning a cultured monoclonal cell line, following increased MSX exposure, then selecting clones with the SPR, as discussed above.
Brand does not teach specific cell culture conditions, such as culture volumes, culture vessels, or MSX concentrations used in the CHO studies. Tian teaches these deficiencies.
Tian relates to a strategy for the improvement of productivity, in regard to manufacturing therapeutic proteins (Abstract). Tian teaches GS -/- CHO cell lines grown initially in standard MSX concentration (6.25 μM), but then exposed to increased MSX concentrations (25 μM), during the seed train expansion (Relevant to instant claims 6, 7, and 14) (Abstract, Introduction-paragraph 8, and Materials and Methods: 2.1). This strategy is shown to increase titer by between 10-19%, and is shown to be scalable, as shown by comparable yields being obtained from bioreactors ranging from 5L – 1000L in culture volume (Relevant to instant claims 8, 9, and 19) (Results: 3.2 – 3.3 and Figures 2 and 3). Additionally, it is shown that cell lines expanded with this method displayed a lesser decrease in titer after extended passaging, when compared to cells expanded with the standard MSX concentration (Results: 3.4 and Figure 4).
It would have been obvious to one skilled in the art, at the time of filing, to combine the teachings of Brand (re-cloning following gene amplification) and Tian (increasing the concentration of selective agent during cell culture expansion). One would have been motivated to apply Brand’s teaching of re-cloning following gene amplification, brought on by exposing the cell culture to increased MSX concentration, to Tian’s teaching of improving titer by an increased MSX concentration during seed train expansion, because the two strategies directly complement each other and both lead to increased titer, which provides clear motivation. Furthermore, both studies teach an increased concentration of selective agent, following initial cloning, although Brand is silent on the exact concentration of selective agent utilized. It should be noted that Tian teaches that the exact mechanism leading to increased productivity at higher MSX concentrations is not fully understood, and discusses several hypotheses that exist to explain the phenomenon (Discussion-paragraph 5). One hypothesis involves gene amplification, in which high concentrations of MSX (100-1000 μM) lead to target gene amplification as well as an increased risk in cell clonality and stability. Tian et al reference a study showing that only 1 out of 9 clones exposed to 25 μM, the lower range limit established in instant claim 7, showed evidence of gene amplification. An additional hypothesis involves increased mRNA transcription levels, resulting from the cells being forced to overexpress the GS protein in order to overcome the increased MSX (GS inhibitor) concentration (Discussion-paragraph 6). However, Tian et al were unable to correlate productivity to target gene transcript levels. Thus, the exact mechanism is unknown. Brand shows that re-cloning, following the application of increased selective agent, allows for the selection/screening of clones/cell cultures, exposed to increased levels of MSX, possessing superior titers (Results: The productivity of recombinant CHO cell lines in attached and suspension culture and Figure 1). Applying this teaching to the Tian, which shows that the application of more rigorous concentrations of selective agent is shown to both enhance overall titer and titer stability over extended passaging, presents a reasonable expectation of success, to further enhance product titer.
In regard to claims 10 and 20, Brand and Tian teach a method for producing a polypeptide of interest, comprising re-cloning a monoclonal cell line, after increasing MSX exposure, as discussed for the 35 U.S.C. 103 rejection of claims 6 and 7.
Tian also teaches that the initial cell cultures, were generated in medium comprising low MSX concentration, and that they were then used for subsequent expansion in medium comprising higher concentrations of MSX (Results: 3.1). These initial cell cultures were used to generate research cells banks and master cell banks.
In regard to claim 17, Brand and Tian teach a method for producing a polypeptide of interest, comprising re-cloning a monoclonal cell line, after increasing MSX exposure, as discussed for the 35 U.S.C. 103 rejection of claims 6 and 7.
Tian also teaches that CHO cell cultures are the most prevalent system for the production of biologics, accounting for ~70% of the industrial processes for biological therapeutic production (Introduction-paragraph 2). It is also taught that monoclonal antibodies are a common form of therapeutic biologic. Tian et al state that the method taught may be used to improve biologics manufacturing. Many of the antigens referenced (PD-1, PD-L1, CTLA-4, VEGF, CD20, and HER2) in instant claim 17, are targets of therapeutic biologics, as evidenced by Golay (Tables 2 and 3). Therefore, the it would have been obvious to use the method taught by Brand to produce a recombinant antibody targeting one of the antigens referenced in instant claims 17.
Conclusion
No claims allowed.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to MATTHEW CURRAN METCALF whose telephone number is (571)272-5520. The examiner can normally be reached 7:30AM-5:00PM.
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, Joanne Hama, can be reached at (571)272-2911. 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.
/MATTHEW CURRAN METCALF/Examiner, Art Unit 1647 /JOANNE HAMA/Supervisory Patent Examiner, Art Unit 1647
Prosecution Insights