Prosecution Insights
Last updated: April 19, 2026
Application No. 18/547,794

RIBONUCLEOTIDE REDUCTASE (RNR) INHIBITORS AND USES THEREOF

Non-Final OA §103
Filed
Aug 24, 2023
Examiner
DAHLIN, HEATHER RAQUEL
Art Unit
1629
Tech Center
1600 — Biotechnology & Organic Chemistry
Assignee
Boundless Bio Inc.
OA Round
1 (Non-Final)
46%
Grant Probability
Moderate
1-2
OA Rounds
3y 5m
To Grant
97%
With Interview

Examiner Intelligence

Grants 46% of resolved cases
46%
Career Allow Rate
61 granted / 133 resolved
-14.1% vs TC avg
Strong +51% interview lift
Without
With
+50.7%
Interview Lift
resolved cases with interview
Typical timeline
3y 5m
Avg Prosecution
83 currently pending
Career history
216
Total Applications
across all art units

Statute-Specific Performance

§101
4.6%
-35.4% vs TC avg
§103
33.3%
-6.7% vs TC avg
§102
19.8%
-20.2% vs TC avg
§112
25.7%
-14.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 133 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 . Priority This Application is a 371 of PCT/US2022/018279, filed March 1, 2022, and claims priority benefit of U.S. Provisional Application No. 63/155,441, filed March 2, 2021. Information Disclosure Statement The information disclosure statement (IDS) submitted on August 24, 2023 is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner. Claim Status Claims 1, 4, 6, 8, 10, 13-16, 22, 26, 28, 31, 32, 35 and 37-42 are currently pending and subject to examination. 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. 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) 1, 4, 6, 8, 10, 13-16, 22, 26, 28, 31, 32, 35 and 37-42 is/are rejected under 35 U.S.C. 103 as being unpatentable over Ueno & Hoshino (US 2020/0405697 A1, published Dec. 31, 2020) in view of Kohara et al. (Bioorganic & Medicinal Chemistry Letters, Vol. 5, No. 17, pp. 1903-1908, 1995), Tagad et al. (Bioorganic & Medicinal Chemistry, Volume 18, Issue 9, 1 May 2010, Pages 3175-3186) and Ohmoto & Itagaki (US 6,900,207 B2, published May 31, 2005, p. 5228-5235). Claim 1 is directed towards a compound of formula (I) PNG media_image1.png 157 168 media_image1.png Greyscale , for example, PNG media_image2.png 161 121 media_image2.png Greyscale (claim 40). Ueno teaches highly similar antitumor agents which inhibit ribonucleotide reductase (RNR) having formula PNG media_image3.png 141 120 media_image3.png Greyscale (Ueno, Specification, paragraph [0022]), for example, PNG media_image4.png 168 227 media_image4.png Greyscale (id., p. 117, ex. 83) and PNG media_image5.png 198 185 media_image5.png Greyscale (id., p. 183, ex. 349). The compounds of Ueno differ from the instantly claimed compounds in that they have a 1,3,4-oxadiazol-2-one or 1,2,4-oxadiazol-5-one moiety instead of a tetrazole moiety. One of ordinary skill in the art, however, would have a reasonable expectation of success to substitute 1,3,4-oxadiazol-2-one or 1,2,4-oxadiazol-5-one with tetrazole to produce an RNR inhibitor with similar properties because oxadiazolones are well known to be bioisosteres of tetrazole. For example, Kohara teaches that 1,2,4-oxadiazol-5-one is a bioisostere of tetrazole: PNG media_image6.png 231 514 media_image6.png Greyscale Kohara, Abstract; Herein, we demonstrated that the 5-oxo-l,2,4-oxadiazole ring was a novel class of acidic bioisostere of the tetrazole ring. The representative compound, TAK-536 is a new class of potent, orally active and long-acting AII receptor antagonist, which has higher oral bioavailability than CV-11974. Consequently, further chemical modification of TAK-536 was not necessary for improvement of the BA. We believe that a novel class of acidic bioisostere, the 5-oxo1,2,4-oxadiazole ring can be applied to other drug design. Kohara, p. 1908. For example, Ohmoto teaches that oxadiazolone is interchangeable with tetrazole in cysteine protease inhibitors: PNG media_image7.png 128 306 media_image7.png Greyscale PNG media_image8.png 138 241 media_image8.png Greyscale Ohmoto, Specification, col. 9; Ohmoto, Specification, col. 13; PNG media_image9.png 202 298 media_image9.png Greyscale PNG media_image10.png 158 296 media_image10.png Greyscale Ohmoto, Specification, col. 129; Ohmoto, Specification, col. 150. As another example, Tagad teaches 5-oxo-1,2,4-oxadiazole, 5-oxo-1,2,4-thiadiazole, 5-thioxo-1,2,4-oxadiazole and 2-thioxo-1,3,4-oxadiazole derivatives have similar BACE1 inhibitory activity to tetrazole derivatives: PNG media_image11.png 532 715 media_image11.png Greyscale Tagad, p. 3179. Therefore, claim 1 was prima facie obvious at the time of filing. Claims 4, 6, 8, 10, 13-14, 22, 28, 31-32, 35, and 37-40 read on the compound PNG media_image2.png 161 121 media_image2.png Greyscale (claim 40) and thus are prima facie obvious for the reasons given in the rejection of claim 1. Claim 16 is directed towards the compound of claim 1, wherein ring A is a bicyclic 6- to 10-membered ring optionally substituted with O, S, and N. For example, PNG media_image12.png 140 329 media_image12.png Greyscale (claim 40). Ueno teaches a highly similar compound: PNG media_image13.png 173 455 media_image13.png Greyscale (Ueno, Specification, col. 292-293, ex. 235A). While compound 235A differs from the instantly claimed compound in that it has a 1,2,4-oxadiazol-5-one moiety instead of a tetrazole moiety, one of ordinary skill in the art would have a reasonable expectation of success to substitute tetrazole for 1,2,4-oxadiazol-5-one because these are well known bioisosteres and the substitution should produce a compound with similar properties. For example, see the teachings of Kohara, Ohmoto and Tagad above in the rejection of claim 1. Therefore, claim 16 was prima facie obvious at the time of filing. Claim 37 is directed towards the compound of claim 1, wherein: PNG media_image14.png 164 568 media_image14.png Greyscale For example, a compound reading on claim 37 is: PNG media_image15.png 142 177 media_image15.png Greyscale (claim 40) (RBa is deuterium). Ueno teaches a similar compound: PNG media_image16.png 167 257 media_image16.png Greyscale (Ueno, Specification, col. 269-270, ex. 200A). While compound 200A differs from the instantly claimed compound in that it has a 1,2,4-oxadiazol-5-one moiety instead of a tetrazole moiety, one of ordinary skill in the art would have a reasonable expectation of success to substitute tetrazole for 1,2,4-oxadiazol-5-one because these are well known bioisosteres and the substitution should produce a compound with similar properties. For example, see the teachings of Kohara, Ohmoto and Tagad above in the rejection of claim 1. Therefore, claim 37 was prima facie obvious at the time of filing. Claim 41 is directed towards a pharmaceutical composition comprising a compound of claim 1, and a pharmaceutically acceptable excipient. One of ordinary skill in the art would have a reasonable expectation of success to obtain a pharmaceutical composition comprising a compound of claim 1 because Ueno teaches pharmaceutical compositions comprising structural analogs of the compound of claim 1 and pharmaceutically acceptable excipients: In yet another embodiment, the present invention provides a pharmaceutical composition comprising the compound of the present invention or a salt thereof and a pharmaceutically acceptable carrier… With respect to pharmaceutically acceptable carriers, conventional various organic or inorganic carrier substances are used as pharmaceutical materials, and it is formulated as: excipients… Ueno, Specification, col. 47-48. Therefore, claim 41 was prima facie obvious at the time of filing. Claim 42 is directed towards a method of treating cancer in a subject, comprising administering to the subject a compound of claim 1. One of ordinary skill in the art would have a reasonable expectation of success to treat cancer with the compound of claim 1, because Ueno teaches that structural analogs of the compound of claim 1 can be used to treat cancer: In yet another embodiment, the present invention comprises administering an effective amount of the compound of the present invention or a salt thereof to a subject to provide an RNR activity suppression method. Further, the present invention comprises administering an effective amount of the compound of the present invention or a salt thereof to a subject to provide a method of treating RNR-related diseases. In a preferred embodiment, a method of treating RNR-related diseases is a method of treating tumors. In the treatment method, the subjects include human or non-human animal in need of the method. Ueno, Specification, col. 47, lines 43-53. Ueno demonstrates the anti-cancer effects of the compounds in mice transplanted with a human derived blood cancer line (MV-4-11). For example, Figure 1 shows the effects of these analogs: PNG media_image17.png 339 505 media_image17.png Greyscale Ueno, Figure 1. Compare compound 5 with the second compound of claim 40, which differs only by the bioisosteric substitution of tetrazole for 1,3,4-oxadiazol-2-one (they are analogs): PNG media_image18.png 165 119 media_image18.png Greyscale vs. PNG media_image19.png 183 228 media_image19.png Greyscale (Instant Claim 40) (Ueno, Specification, col. 177-178, compound 5). Therefore, claim 42 was prima facie obvious at the time of filing. Given the above teachings, the invention as a whole was prima facie obvious at the time of filing. Conclusion No claim is found to be allowable. Any inquiry concerning this communication or earlier communications from the examiner should be directed to HEATHER DAHLIN whose telephone number is (571)270-0436. The examiner can normally be reached 9-5. 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. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Jeffrey Lundgren can be reached on (571) 272-5541. 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 86-217-9197 (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. /HEATHER DAHLIN/Examiner, Art Unit 1629
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Prosecution Timeline

Aug 24, 2023
Application Filed
Nov 19, 2025
Non-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

1-2
Expected OA Rounds
46%
Grant Probability
97%
With Interview (+50.7%)
3y 5m
Median Time to Grant
Low
PTA Risk
Based on 133 resolved cases by this examiner. Grant probability derived from career allow rate.

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