Prosecution Insights
Last updated: April 19, 2026
Application No. 17/970,874

METHODS FOR ANION-EXCHANGE ANALYSIS OF NUCLEIC ACIDS

Final Rejection §103
Filed
Oct 21, 2022
Examiner
PATEL, PRANAV N
Art Unit
1777
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Waters Technologies Corporation
OA Round
2 (Final)
68%
Grant Probability
Favorable
3-4
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

§103
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 § 103 The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action. Claim(s) 1, 3-5, 7, 9-13, 16-19, and 27 is/are rejected under 35 U.S.C. 103 as being unpatentable over Huber (Journal of Chromatography A, 806 (1998) 3–30), in view of Weisburg et al. (US 20090048439A1). Regarding claims 1, 5 and 27, Huber teaches a method for separating a sample comprising a nucleic acid, the method comprising (abstract, paragraph 2.2): (a) loading a sample comprising a nucleic acid onto an anion-exchange column (Refer paragraph 2.2 on page 6); and (b) eluting the sample from the anion-exchange column using a salt gradient (refer paragraph 2.2 disclosing mobile phase comprising electrolyte as eluting salt and a linear gradient of increasing salt concentration is usually applied for elution”), wherein a mobile phase used in the eluting step comprises a mild ion-pairing cation (refer fig. 14 and table 3 disclosing tetramethylammonium chloride), and wherein a column temperature of the anion-exchange column is between ambient to 60 °C (refer paragraph 3.4 disc). 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). Huber discloses that an increase in temperature from ambient to 60°C improved resolution of DNA fragments (refer paragraph 3.4). Huber also discloses that resolution decreased significantly at 45 and 60°C (refer paragraph 3.4). Discovering optimum temperature range would have been obvious to one of ordinary skill in the art since Huber establishes that temperature is a result effective variable. "[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 the limitation “wherein the salt gradient is produced by a non-ion-pairing salt”, Weisburg teaches isolation of nucleic acid using a combination of NaCl and tetramethylammonium or tetraethylammoniam (refer [0124]). Weisburg further discloses that the addition of tetramethylammonium or tetraethylammoniam provides a function to equalize hydrogen bonding strength of G-C and A-T pairs, thereby reducing the hybridization of contaminating rRNA and mRNA that might normally display advantageous G-C hybridization (refer [0124]). It would have been obvious to one of ordinary skill in the art before the effective filing date of invention to modify the mobile phase to include a combination of NaCl and tetramethylammonium or tetraethylammoniam to equalize hydrogen bonding strength as taught by Weisburg. Regarding claims 3-4, modified Huber teaches limitations of claim 1 as set forth above. Huber discloses that typical eluent concentration is 20 mM o r0.1 M (refer table 3), and discloses 0.5-1.5 M tetramethylammonium chloride (refer table 3). 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 7, modified Huber teaches limitations of claim 1 as set forth above. Applying the method of Huber for sample comprising RNA would have been obvious to one of ordinary skill in the art because Huber discloses that such is known in the art (refer page 26). Regarding claims 9-11, modified Huber teaches limitations of claim 1 as set forth above. Huber teaches two mobile phases (Refer fig. 3 indicating mobile phase A and B) wherein buffering agent being Tris and pH is adjusted to between 7.5 and 8.5 with hydrochloric acid or boric acid (refer paragraph 3.2) suggesting a basic buffering agent. Regarding claims 12-13, modified Huber teaches limitations of claim 1 as set forth above. Huber teaches that the mild ion-pairing cation is tetramethylammonium (Refer table 3). Regarding claim 16-17, modified Huber teaches limitations of claim 1 as set forth above. Huber teaches two mobile phases having pH of 9.0 (Refer fig. 3 indicating mobile phase A and B) Regarding claims 18-19, modified Huber teaches limitations of claim 1 as set forth above. Huber teaches the method uses two mobile phases comprise mild pairing cation (Refer fig. 3 disclosing sodium chloride; paragraph 3.2 disclosing sodium chloride, potassium chloride, and sodium perchlorate being most commonly used gradient formers; table 3 disclosing tetramethylammonium chloride; paragraph 4.2 disclosing tetraethylammonium acetate). Selection of the mild pairing cations would have been obvious to one of ordinary skill in the art from the known mild pairing cations. Response to Arguments Applicant’s arguments with respect to claim(s) 1 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument. Applicant argued: PNG media_image1.png 186 738 media_image1.png Greyscale However, the limitation of combination of elute comprising NaCl and tetraethylammonium is taught by Weisberg. Refer claim rejections above. Conclusion 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. 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

Oct 21, 2022
Application Filed
Aug 19, 2025
Non-Final Rejection — §103
Nov 19, 2025
Response Filed
Mar 05, 2026
Final Rejection — §103 (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

3-4
Expected OA Rounds
68%
Grant Probability
90%
With Interview (+22.2%)
3y 0m
Median Time to Grant
Moderate
PTA Risk
Based on 637 resolved cases by this examiner. Grant probability derived from career allow rate.

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