Prosecution Insights
Last updated: April 19, 2026
Application No. 18/001,995

PROTEIN TAG TO INDUCE LIGAND DEPENDENT DEGRADATION OF PROTEIN/PROTEIN-FUSIONS

Final Rejection §103
Filed
Dec 15, 2022
Examiner
PURDY, KYLE A
Art Unit
1611
Tech Center
1600 — Biotechnology & Organic Chemistry
Assignee
DANA-FARBER CANCER INSTITUTE, INC.
OA Round
2 (Final)
41%
Grant Probability
Moderate
3-4
OA Rounds
4y 0m
To Grant
78%
With Interview

Examiner Intelligence

Grants 41% of resolved cases
41%
Career Allow Rate
395 granted / 968 resolved
-19.2% vs TC avg
Strong +37% interview lift
Without
With
+36.9%
Interview Lift
resolved cases with interview
Typical timeline
4y 0m
Avg Prosecution
79 currently pending
Career history
1047
Total Applications
across all art units

Statute-Specific Performance

§101
1.2%
-38.8% vs TC avg
§103
60.6%
+20.6% vs TC avg
§102
14.8%
-25.2% vs TC avg
§112
14.0%
-26.0% vs TC avg
Black line = Tech Center average estimate • Based on career data from 968 resolved cases

Office Action

§103
DETAILED ACTION Status of Application The Examiner acknowledges receipt of the amendments filed on 2/19/2026 wherein claims 1, 5-8, 13 have been amended and claims 3, 4, 10 and 12 have been cancelled. Claims 1, 2, 5-8 and 13-14 are presented for examination on the merits. The following rejections are made. Response to Applicants’ Arguments Applicant’s amendment filed 2/19/2026 overcomes the rejection of claim 1 made by the Examiner under 35 USC 112(b). This rejection has been withdrawn. Applicant’s arguments filed 2/19/2026 regarding the rejection of claims 1, 2, 5-8 and 13-14 made by the Examiner under 35 USC 103 over Crew et al. (US 2018/0215731) has been considered but is not considered persuasive and is MAINTAINED for the reasons of record in the office action mailed on 11/24/2025. In regards to the 103 rejection, Applicant asserts the following: A) The amendments narrow the claims to more narrowly scope the invention to be reflective of the compounds (e.g. compounds 1, 5) that have been discovered to not degrade any native BET bromodomains or any unrelated off targets in MOLT4 cells after 6-hours of treatment. Instead, the compounds of the invention selectively bind mutant BRD but not WT BRD. In response to A, although the claims have been narrowed, the Examiner is not persuaded that the data provided is demonstrative of unexpected results as there is no comparative data between the compounds deemed obvious. That is, it is unclear if the compounds as claimed (having a methyl substituent) exhibit unexpectedly improved BRD activity relative to similar compounds having a hydrogen substituent. Like the claimed compounds, the prior art compounds possessing a hydrogen exhibit BRD activity. Thus, comparative data between the hydrogen and methyl containing molecules would clarify this question. As to the rest of the structure, the major structural components are obvious as each are described in the specification and claims of the reference application. 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. Claims 1, 2, 5-8 and 13-14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Crew et al. (US 2018/0215731) Crew is directed to bifunctional compounds intended to bind a target protein such that the target protein is placed in proximity to a ubiquitin ligase to effect degradation (and inhibition) of that protein. Crew’s bifunctional compounds contain a cereblon ligand and bifunctional compound having the following generic structure: CLM-L-PTM (see claim 2). CLM is the small molecular cereblon ubiquitin ligase binding moiety and may possess the following structure: PNG media_image1.png 87 129 media_image1.png Greyscale (see claim 8) (see instant claims 1 and 8). The CLM structure described by Crew overlaps with the degron ligand elected in the response filed 8/7/2025. PTM is the protein targeting moiety and may possess one of the following structures: PNG media_image2.png 126 193 media_image2.png Greyscale or PNG media_image3.png 134 195 media_image3.png Greyscale (where R is a linking group (L); see [0217]) or PNG media_image4.png 138 184 media_image4.png Greyscale (see [0291] and claim 19). These PTM structures are substantially overlapping with the targeting ligand TL1 structure elected in the response filed 8/7/2025. L is a linker molecule that connects the CLM and PTM moieties has the generic structure –(AL)q wherein AL may be that of CRL1RL2 where RL1 and RL2 may both be H and q is to be an integer greater than 1 (see claim 9). Thus, an alkyl group of C1 and above is contemplated, e.g. PNG media_image5.png 84 92 media_image5.png Greyscale , with C2, C5 and C8 alkyl groups being contemplated (see claim 9) (see instant claims 4-7). It is noted that the N of the aforementioned groups is already present on the PTM structure and the O is present on the CLM structure (see above). Alternative linking groups are contemplated such as those that include PEG such as PNG media_image6.png 45 128 media_image6.png Greyscale wherein n and o is an integer from between 0-20 (see claim 12). When n or o are independently 0 and 1, the resulting linker would yield a generic structure that overlaps with the structure of instant claim 1. The PEG containing structures of 6 and 7 would have been obvious as well as those structures are broadly provided for by the PEG structure of Crew. It is observed that the modified PEG linker is terminated with an O (of the CLM) and an N (of the PTM) (see instant claim 1). Other linking groups include those having amide bonds such as PNG media_image7.png 38 198 media_image7.png Greyscale and PNG media_image8.png 42 218 media_image8.png Greyscale which overlaps with the linker used in structures 1 and 4 of instant claim 13. The bifunctional compounds of Crew may be provided as a therapeutic composition comprising a pharmaceutically acceptable carrier (see [0021]) (see instant claim 14). Crew fails to teach the elected TL1 structure where R is a methyl. It is noted that the PTM structure of Crew possess a H where the elected structure has a methyl (at the arrow): PNG media_image9.png 156 191 media_image9.png Greyscale . The modification of Crew’s structure to include a methyl group where Crew provides a hydrogen is considered obvious as methyl and hydrogen are interchangeable and structurally analogous. Absent evidence to the contrary, the modification of Crew’s bifunctional compound to include a methyl where hydrogen is taught would reasonably be expected to possess the same chemical properties as the structure possessing a hydrogen. The obvious modification of Crew’s bifunctional compounds would result in compounds of overlapping structure to those claimed and a reasonable expectation that the modified compounds similarly exhibit the ability to bind target proteins such that the target protein is placed in proximity to a ubiquitin ligase to effect degradation. Therefore, the invention as a whole is prima facie obvious to one of ordinary skill in the art at the time the invention was filed, as evidenced by the references, especially in absence of evidence to the contrary. Potentially Relevant Prior Art: Yang et al. (US2022/0117982) 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 extension fee 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 KYLE A PURDY whose telephone number is (571)270-3504. The examiner can normally be reached from 9AM to 5PM. If attempts to reach the examiner by telephone are unsuccessful, the examiner's supervisor, Bethany Barham, can be reached on 571-272-6175. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of an application may be obtained from the Patent Application Information Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see http://pair-direct.uspto.gov. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). /KYLE A PURDY/Primary Examiner, Art Unit 1611
Read full office action

Prosecution Timeline

Dec 15, 2022
Application Filed
Nov 13, 2025
Non-Final Rejection — §103
Feb 19, 2026
Response Filed
Mar 19, 2026
Final Rejection — §103 (current)

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Prosecution Projections

3-4
Expected OA Rounds
41%
Grant Probability
78%
With Interview (+36.9%)
4y 0m
Median Time to Grant
Moderate
PTA Risk
Based on 968 resolved cases by this examiner. Grant probability derived from career allow rate.

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