Prosecution Insights
Last updated: April 19, 2026
Application No. 17/390,064

CONJUGATION OF A CYTOTOXIC DRUG WITH BIS-LINKAGE

Final Rejection §112
Filed
Jul 30, 2021
Examiner
COUGHLIN, MATTHEW P
Art Unit
1626
Tech Center
1600 — Biotechnology & Organic Chemistry
Assignee
Hangzhou Dac Biotech Co. Ltd.
OA Round
6 (Final)
71%
Grant Probability
Favorable
7-8
OA Rounds
2y 5m
To Grant
84%
With Interview

Examiner Intelligence

Grants 71% — above average
71%
Career Allow Rate
702 granted / 984 resolved
+11.3% vs TC avg
Moderate +12% lift
Without
With
+12.2%
Interview Lift
resolved cases with interview
Typical timeline
2y 5m
Avg Prosecution
48 currently pending
Career history
1032
Total Applications
across all art units

Statute-Specific Performance

§101
1.7%
-38.3% vs TC avg
§103
24.9%
-15.1% vs TC avg
§102
20.4%
-19.6% vs TC avg
§112
30.3%
-9.7% vs TC avg
Black line = Tech Center average estimate • Based on career data from 984 resolved cases

Office Action

§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 . DETAILED ACTION Claims 1-22 are pending in the application. Claim 1 is rejected. Claim 4 is objected to. Claims 2, 3 and 5-22 are withdrawn from further consideration. Information Disclosure Statement The Examiner has considered the Information Disclosure Statement(s) filed on January 16th, 2026, November 3rd, 2025 and September 30th, 2025. Response to Amendment / Argument Objections and rejections made in the previous Office Action have been overcome by Applicant's amendments to the claims. Therefore, arguments pertaining to these objections and rejections will not be addressed. On pages 25 and 26 of the response filed November 10th, 2025, Applicant traverses the rejection of claim 1 under 35 USC 112(a). Applicant’s amendments have necessitated changes to the rejection; however, Applicant’s arguments will be addressed as they relate to the rejection below. Applicant refers to the definition in paragraph [0129] of the specification for alleged support of the now claimed structure. Applicant merely points out how the original disclosure is generic to the claimed structure and that “L1 and L2 in Formula (IV) include -NHCO-C1 alkyl-NHCO-.” This issue is addressed in the rejection, a generic claim does not necessarily support an amendment to claim any particular sub-genus thereof. On page 26 of the response, Applicant traverses the rejection of claim 1 in view of an anhydride structure. Applicant refers to paragraphs [0153] and [0165] of the published application for the disclosure that “Lv1 and Lv2 can be anhydride, formed by acid themselves or formed with other C1-C8 acid anhydrides…”. Applicant asserts that this disclosure corresponds to a structure where Lv1 and Lv2 are taken together to form an anhydride. First, the cited disclosure is found in a separate paragraph from the structure recited in the claim. The recited structure is found in paragraphs [0154] that recites “Lv1 and Lv2 are independently selected from…” a list. The structure proposed by Applicant, however, does not result from Lv1 and Lv2 being independently chosen but rather where the structures of Lv1 and Lv2 are both amenable to such a structure formation. Furthermore, the generic structure of formula (II) in paragraph [0147] does not depict an optional bond formed between Lv1 and Lv2. For these reasons, the rejection below is maintained. On pages 26 and 27 of the response, Applicant addresses the rejection of claim 1 regarding dashed bonds. Applicant draws three possible structures including the following two: PNG media_image1.png 97 377 media_image1.png Greyscale The newly added structure at claim 1 requires the following structure: PNG media_image2.png 103 191 media_image2.png Greyscale . The left-depicted alleged possibility is inconsistent with the structure at the end of the claim since it does not contain a bond between L1 and L2 and has a bond between Z1 and Z2. The right depicted alleged possibility is inconsistent with the structure at the end of claim since the structure at the end of the claim does not contain a bond between Z1 and Z2. It is unclear which structures or definitions control the claim scope. Claim Rejections - 35 USC § 112(a) The following is a quotation of the first paragraph of 35 U.S.C. 112(a): (a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention. The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112: The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention. Claim 1 is rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention. This is a new matter rejection. Claim 1 recites: PNG media_image3.png 205 759 media_image3.png Greyscale The structure above does not appear to be disclosed as a preferred embodiment. In the remarks filed November 10th, 2025, Applicant refers to possible definitions of L1 and L2 that could be chosen to arrive at the structure above. The fact that the original disclosure generically encompasses a subsequently presented sub-generic structure does not necessarily mean the sub-generic structure is supported by the original disclosure. MPEP 2163.05(II) states: “See also In re Smith, 458 F.2d 1389, 1395, 173 USPQ 679, 683 (CCPA 1972) ("Whatever may be the viability of an inductive-deductive approach to arriving at a claimed subgenus, it cannot be said that such a subgenus is necessarily described by a genus encompassing it and a species upon which it reads." (emphasis added)).” Regarding relevant structural disclosures, the specification provides a general structure (IV) on page 46 without any direction on arriving at the particular arrangement now claimed. Applicant presents sub-generic structures on pages 47 and 48; however, none disclose a sub-genus where Z1 and Z2 are generic and bound to Lv1 and Lv2 but where L1 and L2 are specifically chosen to contain the now recited structure. For example, Applicant provides the following structures: PNG media_image4.png 145 463 media_image4.png Greyscale . The formula (IV-g) does not appear to embrace the structure of claim 4 since X7 and Y7 are only defined as single atoms or NHNH bound to each other. Even if Applicant were to argue that the species of claim 4 together with the generic structure of formula (IV-f) supports the newly added claim limitation, there are multiple ways in which a sub-genus could be derived and the specification does not provide sufficient guidance on selecting one over another. For instance, Applicant has taken the approach that both amides are part of L1 and L2 and that (to embrace the species of claim 4) X’ and Y’ are considered (presumably) amino. The application as filed discloses X’ and Y’ can each be hydrazide -C(O)NHNH2 such it would also be possible to derive a subgenus inclusive of the species of claim 4 where L1 and L2 each only include one amide structure. The same rationale applies to the now recited partial structure in claim 1. There is no disclosure in the specification to suggest a partial structure where multiple amides are part of L1 and L2 and X’ and Y’ are as originally defined. The new limitation carves out certain structural attributes while not requiring additional groups that were disclosed as part of a larger structure or embodiments. There is no discussion or disclosure in the specification regarding which particular structure features were considered preferred or critical. Claims which change the scope relative to the originally filed claims may lack written description, see In re Ruschig, 371 F.2d 990, 154 USPQ 118 (CCPA) 1967) which supports that the original disclosure of a large genus did not support a later filed claim to a previously unnamed single species. Furthermore, Purdue Pharma L.P. v. Faulding Inc., 230 F.3d 1320, 1326, 56 USPQ2d 1481, 1486 (Fed. Cir.2000) notes that with respect to In re Ruschig, that “Ruschig makes clear that one cannot disclose a forest in the original application, and then later pick a tree out of the forest and say “here is my invention”. In order to satisfy the written description requirement, the blaze marks directing the skilled artisan to that tree must be in the originally filed disclosure.” Furthermore, even if any of the remaining structures partially map to the instant claimed structure, each contains defined positions at Z1, Z2, Lv1 and Lv2 where the instantly claimed provide for myriad (although Z1 and Z2 are currently undefined) different options. For instance, in the following structures: PNG media_image5.png 153 517 media_image5.png Greyscale Even if L1/L2-X7 were interpreted to reduce to an -NH- moiety, the definitions of Lv1 and Lv2 in claim 1 are wildly varied relative to the structures above. There is no guidance or direction on why partial structural attributes from the structures above should be maintained while disregarding others that were disclosed as part of the same embodiment. In this situation, the now carved out structure is not disclosed or discussed in the specification as filed as being a critical part of the invention that should be maintained while all other features of the supporting species and/or sub-generic structures can be eliminated. Claim Rejections - 35 USC § 112(b) 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. Claim 1 is 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. (1 of 3) Claim 1 is rejected as indefinite since the variables Z1 and Z2 are not defined in the claim. (2 of 3) Claim 1 is rejected as indefinite based on the following option appear in both the definitions of Lv1 and Lv2 as well as X’ and Y’: PNG media_image6.png 68 131 media_image6.png Greyscale . Claim 1 has been amended such that m1 is 1 and there is only one instance of each of Lv1, Lv2, X’ and Y’. The structure above, however, contains two valences indicated by a wavy bond. It is unclear how the structures above would be connected to the remainder of the molecule with two open valences but only one point of attachment from L1/L2 or Z1/Z2. (3 of 3) Claim 1 is further rejected as indefinite since the claim recites that “----" in both instances can be a single bond or absent provided that both are not absent at the same time. The provision at the end of claim 1, however, only provides for one instance of a bridging bonding. It is unclear if both instances of “----” cannot be present at the same time or (if not) where the additional bridging bond occurs. Allowable Subject Matter Claim 4 is objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. 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 MATTHEW P COUGHLIN whose telephone number is (571)270-1311. The examiner can normally be reached Monday - Friday, 10 am - 6 pm EST. 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, Joseph McKane can be reached on 571-272-0699. 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. /MATTHEW P COUGHLIN/Primary Examiner, Art Unit 1626
Read full office action

Prosecution Timeline

Jul 30, 2021
Application Filed
Mar 25, 2023
Non-Final Rejection — §112
Jun 12, 2023
Response Filed
Sep 22, 2023
Final Rejection — §112
Jan 29, 2024
Response after Non-Final Action
Feb 15, 2024
Response after Non-Final Action
Mar 21, 2024
Request for Continued Examination
Mar 25, 2024
Response after Non-Final Action
Jul 25, 2024
Non-Final Rejection — §112
Aug 26, 2024
Response Filed
Nov 30, 2024
Final Rejection — §112
Mar 04, 2025
Response after Non-Final Action
Apr 30, 2025
Request for Continued Examination
May 05, 2025
Response after Non-Final Action
Aug 07, 2025
Non-Final Rejection — §112
Nov 10, 2025
Response Filed
Feb 27, 2026
Final Rejection — §112 (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

7-8
Expected OA Rounds
71%
Grant Probability
84%
With Interview (+12.2%)
2y 5m
Median Time to Grant
High
PTA Risk
Based on 984 resolved cases by this examiner. Grant probability derived from career allow rate.

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