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 .
Restriction Requirement and Status of Claims
Pursuant to the Requirement for Restriction/Election, mailed on April 24, 2026,
applicant elects without traverse, in a reply received June 17, 2026, Group I and the
species C-Trop-2-3.
Claims 45-52 have been cancelled, claims 44, 53-55, 58, and 61 have been amended, and claims 64-66 have been added. Applicant asserts C-Trop-2-3 read on claims 44, 53, 54, 56-62, and 64-66. Accordingly, claims 55 and 63 are hereby withdrawn.
Claims 44, 53, 54, 56-62, and 64-66 are examined.
Priority
This application, filed on October 26, 2023, is a National Stage entry from International Application No. PCT/CN2022/089726, filed on April 28, 2022, which claims priority under 35 U.S.C. 119 or 365 to Chines Application No. CN202110475315, filed April 29, 2021. The certified copy of the foreign application has been received.
Information Disclosure Statement
The information disclosure statements (IDSs) filed on October 26, 2023; December 5, 2025; February 11, 2026; and May 22, 2026 have been acknowledged and considered.
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.
Claims 44, 53-54, 56, 62, and 64-65 are rejected under 35 U.S.C. 103 as being unpatentable over WO2020236841 (IDS form submitted October 26, 2023 – Foreign Document Number 1) (“Chen”).
Chen teaches antibody drug conjugates (ADCs) in which the ADC includes one or more hydrophobic drug compounds and linkers with one or more hydrophilic groups (p. 1, ll. 32-34).
Chen also teaches ADCs having a structure represented by Formula (III):
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180
339
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(p. 69).
Embodiment 71 describes R100 is
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124
238
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etc. (p. 84).
Embodiment 187 describes (L71) having the structure:
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345
782
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, where the spacer L1 is a diethylene glycol, Lp is the dipeptide ValCit, and G is a self-immolative spacer with the structure
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116
242
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where L2 is a methylene, A is a bond, L3 is the spacer
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81
117
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, R2 is a hydrophilic moiety, the single asterisk (*) conveys the attachment to an N or O of the Drug moiety (DM), and the triple asterisk (***) conveys attachment to Lp (pp. 33 and 109).
Chen teaches the term “hydrophilic moiety” is defined as a group which increases the aqueous solubility of the DM when the DM is attached to a linker. Polysarcosine is defined as one of the “hydrophilic moieties” having the formula
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123
200
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, where n is an integer between 2 and 25 (p. 23). Table 4A shows compound L71-P1 (p. 220) where the DM has the following structure:
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139
464
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(p. 108).
Chen does not teach an ADC species that has a substituted polysarcosine residue with 10 repeating subunits.
Chen is analogous art to the claimed invention because it is in the same field of preparing ADCs with hydrophilic groups like polysarcosine residues. Therefore, it would have been prima facie obvious to a person having ordinary skill in the art (PHOSITA) to prepare the ADC L71-P1 taught by Chen and arrive at the ADC instantly claimed. Chen teaches ADCs represented by Formula (III) include a maleimide group reacted with a thiol (Q1), a diethylene glycol spacer with a -C(=O)- linkage (L1), a ValCit dipeptide (L2), a self immolative spacer with the structure
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97
182
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, substituted with the spacer
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81
117
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, where the spacer is bonded to a polysarcosine group with 12 repeating units. Chen teaches that the polysarcosine residue can have between 2 and 25 repeating units, which overlaps with repeating unit instantly claimed. Accordingly, claims 44, 53-54, 62, and 64 are prima facie obvious.
Regarding claim 56, Chen teaches the ADCs are useful in the treatment of cancer and useful for inhibiting tumor growth, reducing tumor volume, and/or reducing the tumorigenicity of a tumor (p. 148, lines 30-35).
Regarding claim 59, Chen teaches the “antigen binding fragment” of the ADC refers to at least one portion of an antibody that retains the ability to specifically interact with an epitope of an antigen and includes Fab, Fab', F(ab')2, Fv fragments, scFv antibody fragments.
Regarding claim 65, Chen teaches that the DM of the ADC can be a chemotherapy sensitizer, topoisomerase inhibitors, etc. Examples include duocarmycins, etoposides, etc. (p. 9, lines 18-26). It would have been prima facie obvious to substitute the DM of L71-P1 with a topoisomerase II inhibitor like etopside to arrive at the compounds instantly claimed.
Claims 58-59 are rejected under 35 U.S.C. 103 as being unpatentable over Chen in view of Cardillo T. M. et al., Oncotarget. 2020; 11: 3849-3862 (“Cardillo”).
Chen teaches examples of administering the ADCs to triple negative breast cancer cell HCC70 and HCC1954 (p. 261, lines 5-10).
Chen does not teach the antibody portion of the ADC binds to Trop-2 nor does it teach the antibody portion of the ADC comprises hRS7.
Cardillo teaches administration of the FDA approved ADC Sacituzumab govitecan (SG) in triple negative breast cancer cells, like MDA-MB-231 (pp. 3849, Abstract; p. 3850, 1st column, Figure 2). Cardillo states: “Trop-2 is a 46 KDa transmembrane glycoprotein that is overexpressed on many solid tumor types and is correlated with an overall poor prognosis in patients, making it an attractive target for therapy.” (p. 3850, 1st column). Cardillo teaches HCC1954 cells have high Trop-2 expression (Figure 2 caption). Cardillo also teaches SG targets Trop-2 via the humanized anti-Trop-2 antibody, hRS7 IgG (p. 3850, 1st column).
Chen and Cardillo are considered analogous art to the claimed invention because they are in the same field of administering ADCs to triple negative breast cancer cells. Therefore, it would have been prima facie obvious to modify the antibody portion of the ADC of Chen to target Trop-2, because Cardillo teaches that targeting Trop-2 is an attractive target for therapy. Cardillo also teaches that HCC1954 cell line has high expression of Trop-2, therefore based on these teachings a PHOSITA would have been motivated to modify the antibody binding fragment to incorporate the hRS7 fragment for the ADC to target Trop-2, because Chen teaches administration of ADCs to the HCC1954 cell line (MPEP §2144.06(II)). Accordingly, claims 58-59 are prima facie obvious.
Allowable Subject Matter
Claims 57, 61, and 66 are 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. Close prior art is Chen disclosing the ADC L71-P1 that has a different linker and a different DM. There is no teaching, suggestion, or motivation to change the linker to have an alkyl linker and have the DM be exatecan or belotecan.
Conclusion
Claims 44, 53, 54, 56, 58-60, 62, and 64-65 are rejected.
Claims 57, 61, and 66 are objected to.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to SAHIL CHANDER AGGARWAL whose telephone number is (571)272-7755. The examiner can normally be reached 7am-5pm.
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/SAHIL CHANDER AGGARWAL/Examiner, Art Unit 1623
/CLINTON A BROOKS/Supervisory Patent Examiner, Art Unit 1621
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