Prosecution Insights
Last updated: May 29, 2026
Application No. 18/432,751

STING AGONIST COMPOUNDS AND METHODS OF USE

Non-Final OA §112
Filed
Feb 05, 2024
Priority
Aug 02, 2019 — provisional 62/882,081 +4 more
Examiner
YOO, SUN JAE
Art Unit
1621
Tech Center
1600 — Biotechnology & Organic Chemistry
Assignee
Mersana Therapeutics Inc.
OA Round
2 (Non-Final)
71%
Grant Probability
Favorable
2-3
OA Rounds
4m
Est. Remaining
71%
With Interview

Examiner Intelligence

Grants 71% — above average
71%
Career Allowance Rate
871 granted / 1227 resolved
+11.0% vs TC avg
Minimal +0% lift
Without
With
+0.0%
Interview Lift
resolved cases with interview
Typical timeline
2y 8m
Avg Prosecution
97 currently pending
Career history
1279
Total Applications
across all art units

Statute-Specific Performance

§101
0.7%
-39.3% vs TC avg
§103
20.1%
-19.9% vs TC avg
§102
27.4%
-12.6% vs TC avg
§112
24.1%
-15.9% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1227 resolved cases

Office Action

§112
DETAILED ACTION Notice of Pre-AIA or AIA Status 1. The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Response to Amendment 2. The amendments to the claims filed on August 21, 2025 have been fully considered. The amendments are not sufficient to overcome the outstanding rejection which is maintained. Below are responses to Applicant’s remarks. The claims were previously rejected under 35 USC 112 first paragraph for failing to comply with the written description requirement. Previously, the claims had been amended to recite the embodiment of Rc is C1-4 alkyl optionally substituted with COOH or OCH2COOH. The embodiments were not described in the original disclosure as set forth in the office action dated May 6, 2025. Applicants have now amended the claims to recite RC is H, C1-4 alkyl, -(CH2)3-COOH, -(CH2)4-COOH or (CH2)2-O-CH2-COOH. The original disclosure does not include alkyl substituted with COOH. The ring structures of PNG media_image1.png 256 376 media_image1.png Greyscale for ring 2 are not embodiments that sufficiently describe a genus that contains various five membered heteroaryl rings (vs. PNG media_image2.png 64 64 media_image2.png Greyscale as exemplified above) as well as various structures that bridge the heteroaryl ring to variable Rc. For this reason, the claims are still deemed to lack sufficient support in the original disclosure and as such remain rejected under 35 USC 112. Claims 2-7 and 17 remain rejected. This ground of rejection is hereby made FINAL. Conclusion THIS ACTION IS MADE FINAL. 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 SUN JAE YOO whose telephone number is (571)272-9074. The examiner can normally be reached Mon-Fri 8-5. 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. 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. /SUN JAE YOO/Primary Examiner, Art Unit 1621
Read full office action

Prosecution Timeline

Feb 05, 2024
Application Filed
May 06, 2025
Non-Final Rejection mailed — §112
Aug 21, 2025
Response Filed
Dec 02, 2025
Final Rejection mailed — §112
Jan 30, 2026
Response after Non-Final Action
May 27, 2026
Request for Continued Examination
May 28, 2026
Response after Non-Final Action

Precedent Cases

Applications granted by this same examiner with similar technology

Patent 12637455
NAPHTHYRIDINE AND PYRIDO[3,4-c]PYRIDAZINE DERIVATIVES AS GABAA ALPHA 5 RECEPTOR MODULATORS
3y 8m to grant Granted May 26, 2026
Patent 12636280
Therapeutic Tyrosine Kinase Inhibitors for Relapsing Multiple Sclerosis (RMS)
2y 2m to grant Granted May 26, 2026
Patent 12635400
ORGANOMETALLIC COMPOUND AND APPLICATION THEREOF
2y 6m to grant Granted May 19, 2026
Patent 12623997
Non-Coordinating Anion Activators Containing a Cation with Long Chain Alkoxy Functionalization
4y 0m to grant Granted May 12, 2026
Patent 12612377
PROCESS FOR PREPARING AMINOFURANES
3y 3m to grant Granted Apr 28, 2026
Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

2-3
Expected OA Rounds
71%
Grant Probability
71%
With Interview (+0.0%)
2y 8m (~4m remaining)
Median Time to Grant
Moderate
PTA Risk
Based on 1227 resolved cases by this examiner. Grant probability derived from career allowance rate.

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