Prosecution Insights
Last updated: April 19, 2026
Application No. 18/164,952

Covalent Diabodies and Uses Thereof

Non-Final OA §103
Filed
Feb 06, 2023
Examiner
DUFFY, BRADLEY
Art Unit
1643
Tech Center
1600 — Biotechnology & Organic Chemistry
Assignee
Macrogenics Inc.
OA Round
1 (Non-Final)
54%
Grant Probability
Moderate
1-2
OA Rounds
3y 8m
To Grant
99%
With Interview

Examiner Intelligence

Grants 54% of resolved cases
54%
Career Allow Rate
396 granted / 729 resolved
-5.7% vs TC avg
Strong +45% interview lift
Without
With
+45.4%
Interview Lift
resolved cases with interview
Typical timeline
3y 8m
Avg Prosecution
47 currently pending
Career history
776
Total Applications
across all art units

Statute-Specific Performance

§101
3.2%
-36.8% vs TC avg
§103
27.9%
-12.1% vs TC avg
§102
19.7%
-20.3% vs TC avg
§112
29.8%
-10.2% vs TC avg
Black line = Tech Center average estimate • Based on career data from 729 resolved cases

Office Action

§103
Notice of Pre-AIA or AIA Status The present application is being examined under the pre-AIA first to invent provisions. DETAILED ACTION Claims 1 and 114-132 are pending and are under examination. Claim Objections Claim 132 is objected to for reciting “The use of claim 131”. It is suggested this objection be addressed by amending claim 132, to recite “The method of claim 131”. Claim Rejections - 35 U.S.C. §§ 103 The following is a quotation of pre-AIA 35 U.S.C. 103(a) which forms the basis for all obviousness rejections set forth in this Office action: A patent may not be obtained though the invention is not identically disclosed or described as set forth in section 102 of this title, if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter pertains. Patentability shall not be negatived by the manner in which the invention was made. In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103(a) 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 under 35 U.S.C. 103(a), the examiner presumes that the subject matter of the various claims was commonly owned at the time any inventions covered therein were made absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and invention dates of each claim that was not commonly owned at the time a later invention was made in order for the examiner to consider the applicability of 35 U.S.C. 103(c) and potential 35 U.S.C. 102(e), (f) or (g) prior art under 35 U.S.C. 103(a). Claims 1 and 114-132 are rejected under 35 U.S.C. 103(a) as being unpatentable over Holliger et al (US 2004/0058400 A1, IDS) in view of Alt et al (FEBS L., 454:90-94, 1999, IDS). With respect to the claims, Holliger et al teach bispecific and bivalent antibodies (i.e., diabodies) wherein the first polypeptide has the structure of N-(VLA-VHB)-C and the second polypeptide has the structure of N-(VLB-VHA)-C, with a linker between the VL and VH consisting of too few amino acids to allow the VL domain of the polypeptide to combine with the VH domain of the same polypeptide, such that the VHA and VLA pair and the VHB and VLA pair instead would pair and each form a separate epitope binding site functions (see entire document, e.g., pages 3, 8 and 13 and Examples). Holliger et al teach that antibodies comprise hinge cysteines that forms disulfide bonds and that disulfide bonds can be used to crosslink polypeptides to provide stability and making bispecific antibodies with Fc domains by reduction and reoxidation of two antibodies with different specificities (see e.g., pages 7, 8, 11, 12 and 35-38 and Figures). Holliger et al teach that the constant domains of IgG1 can kill cells by activating complement and that the constant domains of IgG1 bind Fc receptors for other effector functions, while the IgG4 Fc domain limits effector functions (see entire document, e.g., pages 3, 8 and 13 and Examples). Holliger et al further teach that diabodies can be fused to additional proteins or antibody domains, such as a CH3 domain, to increase the size of the diabody for enhanced retention in the serum. Holliger et al teach that the antibodies can bind to HER2, CD3, the hormone drug oestriol, small molecules, CD16 or CD32 (i.e., FcyRI or FcyRll) among other antigens (see pages 4, 9 and 12 and Example 12). Holliger et al teach the antibodies can be humanized (see page 23). Holliger et al teach pharmaceutical compositions comprising such diabodies (see claims). Holliger et al teach that a bispecific antibody targeting HER2 and CD3 can kill cells expressing HER2 and that the bispecific antibody can be used in methods of treating cancer (see e.g., pages 5, 8 and 12). Holliger et al do not teach linking a hinge linker comprising a cysteine residue (which is disfulide linked to the cysteine in the other protein comprised in the antibody) followed by -CH2-CH3 to antibodies to create multimeric antibodies. Alt et al teach fusing a CH3 domain or a hinge linker comprising a cysteine residue (which is disfulide linked to the cysteine in the other protein comprised in the antibody) followed by -CH2-CH3, which are from human IgG1, to a single chain diabody or scFv antibody to increase serum half-life (see entire document, e.g., abstract, Figure 1 and pages 90 and 93-94). Alt et al teach that the antibodies can target tumor antigens, bacteria antigens or receptor molecules (see page 90). Alt et al teach that certain therapeutics require Fc effector functions an long serum half-life (see page 90). Alt et al teach introducing a knob-into-hole structure and additional cysteine residues into the CH3 domain to favor formation of heterodimeric heavy chains (see page 93). Accordingly, it would have been prima facie obvious to make bispecific and bivalent non-human, humanized or human antibodies (i.e., diabodies) wherein the first polypeptide has the structure of N-(VLA-VHB)-C and the second polypeptide has the structure of N-(VLB-VHA)-C, wherein both proteins further comprise a linker with a cysteine residue (which is disulfide linked to the opposite cysteine) and a CH2-CH3 domain from human IgG1 or IgG4 to either the N or C-terminus because adding a linker with a cysteine residue (which is disulfide linked to the opposite cysteine) and a CH2-CH3 domain from human IgG1 or IgG4 would have the advantage of improving half-time of the diabody and have the advantage of increasing stability due to the disulfide bond. In this case, Alt teach that proteins having a cysteine hinge linker-CH2-CH3 domain can be used to increase serum half-life and Holliger teach adding antibody domains to increase serum half-life, so one of skill in the art would be motivated to use the cysteine linker-CH2-CH3 of human IgG1 or IgG4 at either end of the diabody of Holliger as it would be immediately recognized to be a naturally occurring structure in human serum that would increase half-life, including in antibodies that bind to HER2, bacterial antigens from an infection, CD16 and/or CD32 (while the prior art only mentions CD16 and CD32 and claims 121-124 and 126 recite CD16A, CD16B, CD32A and CD32B, the recitation of CD16 and CD32 would be immediately envisioned to include CD16A, CD16B, CD32A and CD32B as these are the known species of CD16 and CD32 which would be at once envisaged, absent a showing otherwise (see MPEP § 2131.02). As the cysteine linker-CH2-CH3 is larger than a CH3 domain, the size of the diabody would be further increased such that the half-life would have the advantage of being further extended compared to a CH3 only fused construct. Furthermore, depending on the application, the construct would have the added advantage of effector functions when desired (with an IgG1 Fc domain) or limited effector functions (with an IgG4 domain that is considered a variant of IgG1) when not desired and the disulfide-linked cysteine bond would have the advantage of increasing stability of the construct. Notably, as set forth in the Supreme Court decision in KSR International Co. v. Teleflex Inc. 82 USPQ2d 1385 (2007): “A person of ordinary skill in the art is also a person of ordinary creativity, not an automaton.”KSR, 82 USPQ2d at 1397. “[I]n many cases a person of ordinary skill will be able to fit the teachings of multiple patents together like pieces of a puzzle.”Id. Office personnel may also take into account “the inferences and creative steps that a person of ordinary skill in the art would employ.” KSR, 82 USPQ2d at 1396. An obviousness determination is not the result of a rigid formula disassociated from the consideration of the facts of a case. Indeed, the common sense of those skilled in the art demonstrates why some combinations would have been obvious where others would not. See KSR Int7 Co. v. Teleflex Inc., 82 USPQ2d 1385 (U.S. 2007) ("The combination of familiar elements according to known methods is likely to be obvious when it does no more than yield predictable results."). In this case, based on the knowledge in the antibody art about making bispecific and bivalent antibodies and antibodies in general, it is submitted that a person of ordinary skill in the art using ordinary creativity would have recognized that adding a cysteine linker-CH2-CH3 domain from human IgG1 or IgG4 to each polypeptide of a diabody would have advantages detailed above. Furthermore, such diabodies could target any antigen as claimed as evidenced by Alt and Holliger, such that diabodies targeting antibodies and pharmaceutical compositions comprising such diabodies for use in methods of treating a HER2 expressing cancer and infectious diseases would also be seen as obvious over the references for similar reasons. Then with respect to claim 127, it is noted that Alt et al teach modifying the CH3 domain to create a knob-in-hole structure along with additional cysteine residues to give the advantage of favoring formation of heterodimeric bispecific constructs. Accordingly, a person of ordinary skill in the art using ordinary creativity would have been motivated to modify the CH3 domain to create a knob-in-hole structure in the diabody-Fc construct suggested by the prior art in order to promote proper heterodimeric formation. Notably, as CH2-CH3 domains from each polypeptide dimerize, without a knob-in-hole structure, the CH2-CH3 domains would be more likely to homodimerize than CH2-CH3 domains with a knob-in-hole structure, which would lead to non-functional homodimers being formed. Therefore, modifying CH2-CH3 domains with a knob-in-hole structure would have an advantage in the suggested constructs and these modified IgG1/IgG4 CH2-CH3 domains with a knob-in-hole structure would have at least one amino acid modification as compared to a wild-type Fc domain. Finally, one of ordinary skill in the art would have a reasonable expectation of success in making such constructs, compositions and using them in methods of treatment as encompassed by the claims as both Alt et al and Holliger et al demonstrate that genetic engineering techniques to join antibody domains using linkers were known in the art and bispecific antibodies had been used to treat diseases in the art. Therefore, the invention as a whole was prima facie obvious to one of ordinary skill in the art at the time the invention was made, as evidenced by the references, especially in the absence of evidence to the contrary. Conclusion No claim is allowed. Any inquiry concerning this communication or earlier communications from the examiner should be directed to Brad Duffy whose telephone number is (571) 272-9935. The examiner can normally be reached at Monday through Friday. If attempts to reach the examiner by telephone are unsuccessful, the examiner's supervisor, Julie Wu, can be reached at (571) 272-5205. The official fax 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). Respectfully, Brad Duffy 571-272-9935 /Brad Duffy/ Primary Examiner, Art Unit 1643 March 11, 2026
Read full office action

Prosecution Timeline

Feb 06, 2023
Application Filed
Mar 11, 2026
Non-Final Rejection — §103 (current)

Precedent Cases

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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
54%
Grant Probability
99%
With Interview (+45.4%)
3y 8m
Median Time to Grant
Low
PTA Risk
Based on 729 resolved cases by this examiner. Grant probability derived from career allow rate.

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