Prosecution Insights
Last updated: April 19, 2026
Application No. 18/249,411

Methods for purifying bacterial polysaccharides

Non-Final OA §102§103§112
Filed
Apr 18, 2023
Examiner
PATEL, PRANAV N
Art Unit
1777
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Pfizer, Inc.
OA Round
1 (Non-Final)
68%
Grant Probability
Favorable
1-2
OA Rounds
3y 0m
To Grant
90%
With Interview

Examiner Intelligence

Grants 68% — above average
68%
Career Allow Rate
433 granted / 637 resolved
+3.0% vs TC avg
Strong +22% interview lift
Without
With
+22.2%
Interview Lift
resolved cases with interview
Typical timeline
3y 0m
Avg Prosecution
45 currently pending
Career history
682
Total Applications
across all art units

Statute-Specific Performance

§101
0.4%
-39.6% vs TC avg
§103
50.9%
+10.9% vs TC avg
§102
17.0%
-23.0% vs TC avg
§112
26.5%
-13.5% vs TC avg
Black line = Tech Center average estimate • Based on career data from 637 resolved cases

Office Action

§102 §103 §112
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 . 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 5-7 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. Regarding claim 5, it is unclear whether the claim is reciting to filter the clarified solution of claim 4 or the Streptococcus pneumoniae serotype 3 polysaccharide solution of claim 1. Regarding claim 6, it is unclear whether the claim is reciting to filter the clarified solution of claim 4 or the Streptococcus pneumoniae serotype 3 polysaccharide solution of claim 1. Regarding claim 7, it is unclear whether the claim is reciting to filter the clarified solution of claim 4 or the Streptococcus pneumoniae serotype 3 polysaccharide solution of claim 1. Claim Rejections - 35 USC § 102 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action: A person shall be entitled to a patent unless – (a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention. (a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention. Claim(s) 1 is/are rejected under 35 U.S.C. 102(a)(2) as being anticipated by Shin et al (US 20150231225A1). Regarding claim 1, Shin teaches method for purifying Streptococcus pneumoniae serotype 3 polysaccharide from a solution comprising said polysaccharide together with contaminants, wherein said method comprises a base treatment step (refer Example 1, paragraph [0062] disclosing maintaining pH at about 7.2 or higher using 3N NaOH, and centrifuged to remove proteins and cell debris). 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. Claim(s) 2-7 and 16-17 is/are rejected under 35 U.S.C. 103 as being unpatentable over Shin et al (US 20150231225A1). Regarding claim 2, Shin teaches limitations of claim 1 as set forth above. Shin teaches (refer [0008]) maintaining pH of culture broth in a range of 7.0 to 9.4. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). "[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." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Regarding claim 3, Shin teaches limitations of claim 2 as set forth above. Shin teaches that the base comprises NaOH (Refer [0039], [0062]). Regarding claim 4, Shin teaches limitations of claim 2 as set forth above. Shin teaches that after base treatment, the suspension is clarified by centrifugation (refer [0062]). Regarding claims 5 and 6, Shin teaches limitations of claim 4 as set forth above. Shin teaches (refer [0064]) filtering the centrifuged solution through a depth filter to remove proteins and cell debris which had not been settled during the centrifugation. Regarding claim 7, Shin teaches limitations of claim 4 as set forth above. Shin teaches that the polysaccharide containing solution is further clarified by ultrafiltration (Refer [0064]). Regarding claim 16, Shin teaches limitations of claim 1 as set forth above. Shin teaches that purified solution of polysaccharide is subject to depth filtration, ultrafiltration, and sterile filtration, all of which inherently provides filtration based on molecular size. Regarding claim 17, Shin teaches limitations of claim 1 as set forth above. Shin teaches that purified solution of polysaccharide is sterilely filtered (refer [0064]). Claim(s) 8-15 and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Shin et al (US 20150231225A1), in view of Morais et al. (2018) Purification of Capsular Polysaccharides of Streptococcus pneumoniae: Traditional and New Methods. Front. Bioeng. Biotechnol. 6:145). Regarding claims 8-10, Shin teaches limitations of claim 2 as set forth above. Shin does not teach that the Streptococcus pneumoniae serotype 3 polysaccharide containing solution is further treated by a flocculation step comprising adding a flocculating agent to the solution, wherein said flocculating agent is a multivalent cation, and wherein said multivalent cation comprises at least one of aluminium, iron, calcium or magnesium. Morais teaches purification of polysacchardies of Streptococcus pneumoniae (refer abstract). On Page 4, Morais discloses that “Macha and colleagues proposed a simplified purification method for CPS types 3, 6B, 14, 19F, and 23F that utilizes lysis by detergent, followed by concentration, ethanol precipitation, aluminum phosphate adsorption and diafiltration with a 300-kDa tangential flow filtration system. The resulting percentage of process impurities was <1.5%, and the recovery was 65–80% (Macha et al., 2014). The advantage of this method is that it replaces phenol precipitation and the use of nucleases and proteases with AlPO4 adsorption and ultrafiltration. The authors reported that AlPO4 is capable of separating two negatively charged compounds (for example, CPS and endotoxin) by selectively binding to endotoxins and separating them from the CPS.”. This disclosure identify use of Alumimun Phosphate to bind and remove contaminants. It would have been obvious to one of ordinary skill in the art to modify the method of Shin to include flocculation step using aluminum phosphate to enable removal of contaminants from polysachharide solution as taught by Morais. Regarding claim 11, modified Shin teaches limitations of claim 8 as set forth above. Shin further teaches that lowering pH of solution to lower than 7 improves protein precipitation (refer [0040]). Regarding claim 12 and 15, modified Shin teaches limitations of claim 8 as set forth above. Morais teaches diafiltration step after flocculation with aluminum phosphate (Refer Page 4). Regarding claim 13, modified Shin teaches limitations of claim 8 as set forth above. Shin further teaches adjusting pH to about 5.5 improves protein precipitation (Refer [0040]). Regarding claim 14, modified Shin teaches limitations of claim 8 as set forth above. Shin further teaches the polysaccharide containing solution is further clarified by an activated carbon filtration step (refer [0055]). Regarding claim 18, modified Shin teaches limitations of claim 12 as set forth above. Shin further teaches adjusting pH to about 5.5 improves protein precipitation (Refer [0040]). Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. WO 2020/058963 teaches purifying polysaccharides of Streptococcus pneumoniae. Any inquiry concerning this communication or earlier communications from the examiner should be directed to PRANAV PATEL whose telephone number is (571)272-5142. The examiner can normally be reached M-F 6AM-4PM. 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, Bobby Ramdhanie can be reached at (571) 270-3240. 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. /PRANAV N PATEL/Primary Examiner, Art Unit 1777
Read full office action

Prosecution Timeline

Apr 18, 2023
Application Filed
Mar 24, 2026
Non-Final Rejection — §102, §103, §112 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

1-2
Expected OA Rounds
68%
Grant Probability
90%
With Interview (+22.2%)
3y 0m
Median Time to Grant
Low
PTA Risk
Based on 637 resolved cases by this examiner. Grant probability derived from career allow rate.

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