Prosecution Insights
Last updated: April 19, 2026
Application No. 17/622,360

A CONJUGATE OF A CYTOTOXIC AGENT TO A CELL BINDING MOLECULE WITH BRANCHED LINKERS

Final Rejection §102§112
Filed
Dec 23, 2021
Examiner
PUTTLITZ, KARL J
Art Unit
1646
Tech Center
1600 — Biotechnology & Organic Chemistry
Assignee
Hangzhou Dac Biotech Co. Ltd.
OA Round
2 (Final)
69%
Grant Probability
Favorable
3-4
OA Rounds
2y 8m
To Grant
87%
With Interview

Examiner Intelligence

Grants 69% — above average
69%
Career Allow Rate
974 granted / 1409 resolved
+9.1% vs TC avg
Strong +18% interview lift
Without
With
+18.2%
Interview Lift
resolved cases with interview
Typical timeline
2y 8m
Avg Prosecution
58 currently pending
Career history
1467
Total Applications
across all art units

Statute-Specific Performance

§101
0.7%
-39.3% vs TC avg
§103
37.5%
-2.5% vs TC avg
§102
11.3%
-28.7% vs TC avg
§112
26.8%
-13.2% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1409 resolved cases

Office Action

§102 §112
DETAILED ACTION 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 . The rejections under sections 112(a), 112(b), and 103 are withdrawn in view of Applicant’s amendments and remarks in connection with these grounds of rejections. The rejection under improper Markush Grouping is maintained, below: Claim Rejections - Rejection under the Judicially Created Doctrine of Improper Markush Grouping Claims 44 and 64-74 are rejected under the judicially created doctrine of "improper Markush grouping". The Markush group of Formula (VIII) contains a plethora of nested variables. This is an improper grouping of alternatively useable species. MPEP 803.02 describes a Markush grouping as " ... "selected from the group consisting of A, Band C." The examiner respectfully directs the Applicant's attention to MPEP 803.02 shown below for convenience: "A Markush-type claim recites alternatives in a format such as "selected from the group consisting of A, Band C." See Ex parte Markush, 1925 C.D. 126 (Comm'r Pat. 1925). The members of the Markush group (A, B, and C in the example above) ordinarily must belong to a recognized physical or chemical class or to an art-recognized class. However, when the Markush group occurs in a claim reciting a process or a combination (not a single compound), it is sufficient if the members of the group are disclosed in the specification to possess at least one property in common which is mainly responsible for their function in the claimed relationship, and it is clear from their very nature or from the prior art that all of them possess this property. Inventions in metallurgy, refractories, ceramics, pharmacy, pharmacology and biology are most frequently claimed under the Markush formula but purely mechanical features or process steps may also be claimed by using the Markush style of claiming. (See MPEP § 2173.05(h))." Furthermore, the members of a proper Markush grouping " ... ordinarily must belong to a recognized physical or chemical class or to an art-recognized class." MPEP 803.02 also states that members of a Markush grouping are " ... sufficiently few in number or so closely related that a search and examination of the entire claim can be made without serious burden." This paragraph of the MPEP is shown below for convenience: "If the members of the Markush group are sufficiently few in number or so closely related that a search and examination of the entire claim can be made without serious burden, the examiner must examine all the members of the Markush group in the claim on the merits, even though they may be directed to independent and distinct inventions. In such a case, the examiner will not follow the procedure described below and will not require provisional election of a single species. (See MPEP § 808.02.)" A Markush claim contains an "improper Markush grouping" if: 1. The species of the Markush group do not share a "single structural similarity," - Meaning they do not belong to the same recognized physical or chemical class or same art-recognized class (see explanation supra), or 2. The species do not share a common use, - Meaning they are not disclosed in the specification or known in the art to be functionally equivalent. If 1 or 2 above apply to a Markush grouping, a rejection under the judicially approved "improper Markush grouping" doctrine is proper. The compounds of Formula (III) do not share a "single structural similarity". For a Markush grouping to be proper, the alternatives represented by the grouping must have a "significant structural element that is shared by all of the alternatives" or the species must all share a common use and recognized as "functionally equivalent". A significant structural element that is shared by all of the alternatives refers to cases where the compounds share a common chemical structure which occupies a large portion of their structures, or in case the compounds have in common only a small portion of their structures, the commonly shared structure constitutes a structurally distinctive portion in view of existing prior art, and the common structure is essential to the common property or activity. Each alternative does not have a common chemical structure which occupies a large portion of the structure or have a structurally distinctive portion in view of the prior art which is essential to the claimed common activity/properties. Here there is no common structure that occupies a significant portion of the compounds of Formula (III) since the entire structure is highly variable: PNG media_image1.png 138 256 media_image1.png Greyscale See definitions in claim 44. Additionally, as a result of the wide range of compounds possible by the instant Markush formula, each compound does not belong to the same recognized physical or chemical class or to the same art-recognized class and no credible evidence for a common use amongst all claimed compounds exists. A person of ordinary skill in the art would understand that compounds with such greatly varied structure cannot be expected to have predictable properties. This is a central concept to basic organic chemistry and common knowledge of those with ordinary skill in the art and taught in the first chapter of the organic text CAREY, FA. Organic Chemistry 6th Ed. McGraw Hill. 2006, chapter 1, p. 9. Therefore, in the absence of evidence to the contrary, all compounds within the metes and bounds of the extraordinarily large Markush grouping of the instant claims cannot be individually envisioned and each expected to be functionally equivalent. This rejection may be overcome by either amending the claims to include only the species that share a single structural similarity and a common use such as the compounds which have a constant core and are clearly enabled by the instant specification. Notwithstanding Applicant’s amendments, there is no common structure that occupies a significant portion of the compounds of Formula (III) and entire structure is highly variable. Therefore, the rejection is maintained. The following is a new ground of rejection, necessitated by Applicant’s amendments: Claim Rejections - 35 USC § 102 The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action: A person shall be entitled to a patent unless – (a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention. Claims 44, 65-69, 71, 73, 74 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Jain et al., Pharm Res (2015) 32:3526–3540 (Jain). Jain teaches the mc-vc-PABC-MMAE conjugate at page 3531: PNG media_image2.png 836 1140 media_image2.png Greyscale The above conjugate anticipates the rejected claims wherein: V2, L2, W-D2 are absent (w’ is “absent”); V1 is mc: PNG media_image3.png 78 414 media_image3.png Greyscale see new claim 66; L1 is val-cit (vc, wherein L1 is (Aa)r r = 2); W is the self-immolative spacer PBAC; D1 is MMAE; and Q1 is side chain citrulline (vc). Some of rejected dependent claims recite groups that are not present in the above structure but may be absent in the definitions recited in claim 44. The ependant claims do not explicitly require these groups to be present, and therefore, these structures are not actually required by the dependent claims. The following are new grounds of rejection, which are necessitated by Applicant’s amendments: 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 44 and 64-74 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 64 recites groups for W, L and V that are not listed in the corresponding definitions in claim 44. Therefore, the definitions of these groups in claim 44 are unclear. 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. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to KARL J PUTTLITZ whose telephone number is (571)272-0645. The examiner can normally be reached on Monday to Friday from 9 a.m. to 5 p.m. If attempts to reach the examiner by telephone are unsuccessful, the examiner's acting supervisor, Janet Epps-Smith, can be reached at telephone number (571)272-0757. 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). /KARL J PUTTLITZ/ Primary Examiner, Art Unit 1646
Read full office action

Prosecution Timeline

Dec 23, 2021
Application Filed
Dec 05, 2023
Response after Non-Final Action
Jul 21, 2025
Non-Final Rejection — §102, §112
Oct 23, 2025
Response Filed
Jan 16, 2026
Final Rejection — §102, §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

3-4
Expected OA Rounds
69%
Grant Probability
87%
With Interview (+18.2%)
2y 8m
Median Time to Grant
Moderate
PTA Risk
Based on 1409 resolved cases by this examiner. Grant probability derived from career allow rate.

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