Prosecution Insights
Last updated: April 19, 2026
Application No. 18/258,065

SARS-COV-2 MPRO INHIBITOR COMPOUNDS

Non-Final OA §103§112
Filed
Jun 16, 2023
Examiner
HAVLIN, ROBERT H
Art Unit
1626
Tech Center
1600 — Biotechnology & Organic Chemistry
Assignee
Nxera Pharma UK Limited
OA Round
1 (Non-Final)
53%
Grant Probability
Moderate
1-2
OA Rounds
2y 11m
To Grant
80%
With Interview

Examiner Intelligence

Grants 53% of resolved cases
53%
Career Allow Rate
534 granted / 1016 resolved
-7.4% vs TC avg
Strong +27% interview lift
Without
With
+27.2%
Interview Lift
resolved cases with interview
Typical timeline
2y 11m
Avg Prosecution
99 currently pending
Career history
1115
Total Applications
across all art units

Statute-Specific Performance

§101
1.0%
-39.0% vs TC avg
§103
30.8%
-9.2% vs TC avg
§102
24.8%
-15.2% vs TC avg
§112
28.2%
-11.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1016 resolved cases

Office Action

§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 . Priority This application is a 371 of PCT/GB2021/053374 (12/20/2021) and claims foreign priority to UNITED KINGDOM 2020190.1 (12/18/2020) UNITED KINGDOM 2107385.3 (05/24/2021). Election/Restrictions Applicant's election without traverse of Group I, claims 1-24, in the reply filed on 12/2/25 is acknowledged. Applicant also elected the following species of Example 18: PNG media_image1.png 274 290 media_image1.png Greyscale reading on claim 1 formula (I’) PNG media_image2.png 189 219 media_image2.png Greyscale when A is 2-fluoro-4-chloro-phenyl; L is -CH=CH-; X is 2-isobutyl; R2,R3,R9 are H; Q is -C(O)-C(O)-NH2; Z is 2-oxopyrrolidin-3-yl; (a.k.a: (2S)-N-(4-amino-3,4-dioxo-1-((S)-2-oxopyrrolidin-3-yl)butan-2-yl)-2-((E)-3-(4-chloro-2-fluorophenyl)acrylamido)-4-methylpentanamide) determined to read on claims 1-7, 9-10, 12-13, 15, 17-18, 20-24. As detailed in the following rejections, the generic claim encompassing the elected species was not found patentable. Therefore, the provisional election of species is given effect, the examination is restricted to the elected species only, and claims not reading on the elected species are held withdrawn. MPEP 803.02; Ex parte Ohsaka, 2 USPQ2d 1460, 1461 (Bd. Pat. App. lnt. 1987). Accordingly, claims 8, 11, 14, 16, 19 are hereby withdrawn. Should applicant, in response to this rejection of the Markush-type claim, overcome the rejection through amendment, the amended Markush-type claim will be reexamined to the extent necessary to determine patentability of the Markush-type claim. See MPEP 803.02. Specification The spacing of the lines of the specification is such as to make reading difficult. New application papers with lines 1 1/2 or double spaced (see 37 CFR 1.52(b)(2)) on good quality paper are required. Thus, the specification is objected to for not conforming to 37 CFR 1.52(b)(2): “(2) The specification (including the abstract and claims) … must have: (i) Lines that are 1 1/2 or double spaced”. 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 15 and 23 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. Claim 15 uses the following language: PNG media_image3.png 102 792 media_image3.png Greyscale which is not clear whether the end “where” clause applies to both “wherein R1 and R1a” clauses. Claim 23 has the following language: PNG media_image4.png 66 787 media_image4.png Greyscale which is unclear as to what amount of “having … activity” is required. Furthermore, the claim is using functional language in a manner that one of skill in the art would not clearly understand how the structure of the compound is limited by the language. See MPEP 2173.05(g) (“the use of functional language in a claim may fail “to provide a clear-cut indication of the scope of the subject matter embraced by the claim” and thus be indefinite. In re Swinehart, 439 F.2d 210, 213 (CCPA 1971). For example, when claims merely recite a description of a problem to be solved or a function or result achieved by the invention, the boundaries of the claim scope may be unclear. Halliburton Energy Servs., Inc. v. M-I LLC, 514 F.3d 1244, 1255, 85 USPQ2d 1654, 1663 (Fed. Cir. 2008) (noting that the Supreme Court explained that a vice of functional claiming occurs “when the inventor is painstaking when he recites what has already been seen, and then uses conveniently functional language at the exact point of novelty”) (quoting General Elec. Co. v. Wabash Appliance Corp., 304 U.S. 364, 371 (1938))”). 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 1-7, 9-10, 12-13, 15, 17-18, 20-24 are rejected under 35 U.S.C. 103 as being unpatentable over Zhang et al. (J. Med. Chem. 2020-02-11, 63, p. 4562−4578, S1-S6) in view of Liu et al. (WO2020030143, published 2020-02-13 (cited by Applicant), citations to English equivalent US20220112177) and Patani et al. (Chem. Rev., 1996, Vol. 96, No. 8, p. 3147-3176). Zhang teaches coronavirus inhibitor ketoamide compounds of the formula 11: PNG media_image5.png 226 311 media_image5.png Greyscale Including the species 11d (S4): PNG media_image6.png 241 442 media_image6.png Greyscale which was demonstrated to inhibit SARS-CoV Mpro in assays (p. 4564, S4). Zhang’s compound 11d corresponds to claim 1 formula (I’) PNG media_image2.png 189 219 media_image2.png Greyscale when: A is phenyl (i.e., T1,T2 are CH; R4,5,6 are H); L is -CH=CH-; X is 2-isobutyl; R2,R3,R9 are H; Q is -C(O)-C(O)-NR1R1a; R1 is H; R1a is 2-isobutyl; Z is 2-oxopyrrolidin-3-yl. Zhang’s compound 11d is within the scope of instant claim but for the following proviso: PNG media_image7.png 172 740 media_image7.png Greyscale specifying that R3,4,5,6,7,8 are not all H. In other words, the instant claims require a substitution on Zhang’s phenyl ring. Zhang also teaches inhibitor compound 11l (S4): PNG media_image8.png 224 437 media_image8.png Greyscale . Liu teaches antiviral ketoamide compounds for treating diseases related to coronavirus (Abstract, claim 1), including of the formula A: PNG media_image9.png 200 357 media_image9.png Greyscale Liu’s Formula A encompasses the elected species and instant claim 1. Liu also teaches species including A115 (claim 6, p34): PNG media_image10.png 213 440 media_image10.png Greyscale Liu teaches coronavirus inhibition assays and in vivo studies with the compounds (p. 99-103). Patani teaches the well-known technique of bioisosterism in pharmaceutical development which is routinely used in the art (p. 3147-48). Patani teaches that it was routine to modify rings to add chlorine substituents and that maintained utility and even improved pharmaceuticals by blocking metabolism in changing hydrogen to chlorine (p. 3153-54). One of ordinary skill in the art following the teaching of Zhang would have considered applying the well-known technique of bioisosterism to modify the phenyl ring of compound 11d to include a chlorine substituent (i.e. instant claim 1, R6 is Cl), particularly in view of the teaching by Liu in the structurally-related compounds with the same utilities taught therein having Cl substituents at the same corresponding position in the pharmacophore. Particularly, Liu teaches a genus where the phenyl group can be substituted by halogens, Cl and Br (Liu claim 1 substituted arylalkenylene, [0048]). One of ordinary skill in the art would have had a reasonable expectation of success in view of each Zhang and Liu teaching the structurally related corresponding compounds as having pharmaceutical activity and performing such as modification is routinely done in the art as taught by Patani. The level of skill in the art is very high such that one of ordinary skill in the art would consider routine the combination of elements from the teaching of the art. One of ordinary skill in the art would have recognized that the results of the combination would be predictable due to the well-known nature and optimizations routinely performed in the art. Thus, one of ordinary skill in the art would have arrived at the invention as claimed before the effective filing date with a reasonable expectation of success. Conclusion No claims allowed. Any inquiry concerning this communication or earlier communications from the examiner should be directed to ROBERT H HAVLIN whose telephone number is (571)272-9066. The examiner can normally be reached 9am - 6pm. 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, Kortney Klinkel can be reached at (571) 270-5293. 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. /ROBERT H HAVLIN/Primary Patent Examiner, Art Unit 1626
Read full office action

Prosecution Timeline

Jun 16, 2023
Application Filed
Jan 29, 2026
Non-Final Rejection — §103, §112 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

Patent 12528943
Reactive Disperse Yellow Dye for Supercritical CO2 Dyeing and Methods of Production and Use Thereof
2y 5m to grant Granted Jan 20, 2026
Patent 12516383
METHODS FOR DETECTING HEREDITARY CANCERS
2y 5m to grant Granted Jan 06, 2026
Patent 11993569
3-AMINO-4-HALOCYCLOPENTENE CARBOXYLIC ACIDS AS INACTIVATORS OF AMINOTRANSFERASES
2y 5m to grant Granted May 28, 2024
Patent 11952362
COMPOSITIONS AND METHODS FOR TREATING EPIGENETIC DISEASE
2y 5m to grant Granted Apr 09, 2024
Patent 11926871
SYNTHESIZING BARCODING SEQUENCES UTILIZING PHASE-SHIFT BLOCKS AND USES THEREOF
2y 5m to grant Granted Mar 12, 2024
Study what changed to get past this examiner. Based on 5 most recent grants.

AI Strategy Recommendation

Get an AI-powered prosecution strategy using examiner precedents, rejection analysis, and claim mapping.
Powered by AI — typically takes 5-10 seconds

Prosecution Projections

1-2
Expected OA Rounds
53%
Grant Probability
80%
With Interview (+27.2%)
2y 11m
Median Time to Grant
Low
PTA Risk
Based on 1016 resolved cases by this examiner. Grant probability derived from career allow rate.

Sign in with your work email

Enter your email to receive a magic link. No password needed.

Personal email addresses (Gmail, Yahoo, etc.) are not accepted.

Free tier: 3 strategy analyses per month