US Patent 10,407,673: Critical claims assessment and US patent landscape

United States Patent 10,407,673 claims a chemoenzymatic glycoengineering workflow built around a mutant endoglycosidase S2 (EndoS2) that swaps hydrolyzing activity down and transglycosylation activity up, with the mutant defined by specific residue windows and at least one key substitution: D182Q. The asserted end product is then used in downstream therapeutic contexts, including cancer treatment by administering the resulting glycoprotein.

What is the core inventive concept in claim 1?

Claim 1 is the anchor. It defines a method with four linked technical constraints:

Enzymology framework
- Use a mutant EndoS2.
- Mutant is made by introducing one or more mutations into a wild-type EndoS2 sequence at peptide-region residue windows:
  - 133–143
  - 177–178
  - 182
  - 187–189
  - 221–231
  - 232–237
Activity phenotype constraints
- The mutant EndoS2 has:
  - lower hydrolyzing activity than wild-type EndoS2
  - higher transglycosylation activity than wild-type EndoS2
Key residue requirement
- “wherein the mutation at residue 182 is D I82Q”
Chemical coupling step
- “coupling an activated oligosaccharide to a glycoprotein acceptor”

The method is thus not simply “using EndoS2 mutants.” It is limited by a phenotype claim (directional activity shift) plus genotype constraints (residue windows + D182Q).

Claim 1 as a patent-usable claim chart (high level)

Element	Claim 1 requirement	Claim 1 risk/precision
Enzyme	Mutant EndoS2	Medium. “Mutant” scope is broad unless sequence is tied tightly to SEQ IDs.
Mutation placement	Mutations in specified residue windows (133–143; 177–178; 182; 187–189; 221–231; 232–237)	Medium-high; residue windows narrow practical design space.
Specific mutation	Residue 182 = D→Q (D182Q)	High; this is a single-point requirement that competitors must avoid.
Function	Hydrolyzing activity lower and transglycosylation activity higher than wild-type	High in litigation. “Higher/lower” can become a measurable dispute point.
Chemistry step	Coupling activated oligosaccharide to acceptor glycoprotein	Low-medium; the field widely uses activated glycan donors.

How broad are claims 2–4 relative to claim 1?

Claim 2 (additional narrowing)

“one or more mutations are at residues T138, D226, T227, and/or T228.”

This limits a subset of positions within the windows already defined. It does not remove D182Q, so D182Q remains mandatory.

Claim 3 (catalog of allowed substitutions)

Mutations selected from:

T138D, T138E, T138F, T138H, T138K, T138L, T138M, T138N, T138Q, T138R, T138V, T138W
D226Q, T227Q, T228Q

This is a finite list. While claim 1 allows “one or more mutations” in multiple windows, claim 3 narrows the mutational palette to specific amino-acid swaps.

Claim 4 (sequence-based fallback)

“mutant comprises the sequence of SEQ ID NO:6…SEQ ID NO:17, and SEQ ID NO:2…SEQ ID NO:5.”

This is the most enforceable form in practice because sequence IDs often define the exact mutant(s) that were characterized in the specification.

Net effect: claims 2–4 create multiple overlapping scopes:

broad: claim 1 (activity + residue-window constraints + D182Q)
narrower: claim 2/3 (specific residue sets and substitution patterns)
tightest: claim 4 (enumerated sequences)

What is the donor/acceptor scope (claims 5–11)?

Claim 5: Activated oligosaccharide = glycan oxazoline

“activated oligosaccharide is a glycan oxazoline.”

This is a donor format limitation. In the enzymatic transglycosylation space, glycan oxazolines are a standard activated donor form, so the claim is not novel at the donor-format level. The novelty is intended to sit in the EndoS2 mutant phenotype rather than the donor class.

Claim 6: Donor structure is heavily enumerated

Claim 6 defines N-glycan oxazolines with:

formula variables R1, R2, R3
R1 includes H or GlcNAc attached via β-1,4 linkage
R2 and R3 cover a wide set of Man-based and Man-substituted patterns including:
- Man, Man2, Man3
- biantennary Man structures (tetra/penta)
- GlcNAc-containing variants
- galactose-, sialylated-, fucosylated- variants
- fucose and neuraminic acid combinations
- n from 1 to 3 in specific repeating patterns

This is extremely broad on donor identity while still keeping to N-glycans that match the donor-design schema.

Claim 7–8: Acceptors require GlcNAc

Claim 7: glycoprotein acceptor contains GlcNAc monosaccharide
Claim 8: acceptor is a non-fucosylated GlcNAc-acceptor

These acceptor constraints align with transglycosylation “handoff” mechanics commonly used for EndoS-family enzymes that target specific glycan motifs.

Claim 9–10: Acceptors include antibodies and core-fucosylated/non-fucosylated IgG acceptors

Claim 9 includes acceptors such as:
- glycopeptides, glycoproteins, antibodies, fragments
Claim 10 narrows further:
- “core fucosylated or non-fucosylated GlcNAc-IgG acceptor or fragment”

Claim 11: Antibody acceptors are enumerated

Claim 11 lists a long set of monoclonal antibodies and fragments (cetuximab, rituximab, trastuzumab, adalimumab, etc., plus many others).

Practical scope note: a claim listing named biologics is common to establish enablement and to show utility, but its enforcement posture is often driven more by the structural acceptor requirement (GlcNAc IgG acceptor) than by whether a specific named antibody is used.

What does claim 12 add (and what does it not add)?

Claim 12:

“method for treating cancer”
administering “an effective amount of a glycoprotein prepared by the method of claim 1”

This is a classic downstream use claim. It does not change the upstream enzyme/chemistry boundary defined by claim 1. It adds a therapeutic indication layer, typically evaluated against obviousness and utility standards rather than freestanding chemical novelty.

Where does novelty likely sit, and where is the claim vulnerable?

Likely novelty center

The combination of:
1. D182Q in EndoS2
2. optional additional mutations within specific residue windows
3. an activity phenotype: reduced hydrolysis and enhanced transglycosylation
4. use with glycan oxazoline donors to engineer glycoproteins

This is a constrained genotype-to-function mapping.

Vulnerable areas for challengers

Phenotype language (“lower/higher activity”)
- “lower than wild-type” and “higher than wild-type” invites disputes around assay conditions, endpoints, and baseline comparisons.
Breadth from activity criteria
- If multiple mutants (not limited to the specific SEQ IDs in claim 4) achieve the same directional activity shift, claim 1 could become broader than the actual enabling dataset.
Donor and acceptor breadth
- Claim 6 plus claims 7–11 expand donor and acceptor scope widely; challengers can argue lack of full support if the spec does not demonstrate transglycosylation performance across that breadth.
EndoS2 mutant field overcrowding
- If prior art already discloses EndoS mutants with enhanced transglycosylation via similar substitutions (including D→Q at key catalytic/residue positions), the novelty of D182Q and the residue-window patterns becomes contestable.

How to read the patent landscape risk for this claim set (US market lens)

Without reprinting the full file history and without a citation list provided here, the landscape evaluation must be grounded in how patents in this space usually cluster:

1) Likely prior-art family blocks that matter

For an EndoS2 glycoengineering patent in the US, the most relevant landscape usually consists of:

EndoS (endoglycosidase from S. pyogenes) and EndoS2 enzyme engineering patents
EndoS-family transglycosylation patents that focus on:
- donor activation (e.g., oxazoline)
- acceptor scope (GlcNAc motifs, IgG acceptors)
- engineered enzyme variants that enhance transglycosylation vs hydrolysis
Glycan oxazoline donor patents and their coupling methods
Downstream antibody glycoengineering and cancer treatment use patents

2) Key infringement design-arounds competitors will use

Because claim 1 hard-codes D182Q, most design-arounds will attempt at least one of:

avoiding D182Q at residue 182
using a mutant outside the listed residue windows in claim 1
using a donor format other than glycan oxazoline
using acceptors without the required GlcNAc motif
changing therapeutic claim coverage (harder, since claim 12 tracks claim 1 product)

From a freedom-to-operate perspective, the single-point D182Q requirement is the clearest “stop sign.” If competitors can demonstrate noninfringing enzyme variants that still deliver the needed glycan transfer, the claim’s practical reach narrows.

What would an examiner or court likely focus on for validity?

Anticipation/obviousness emphasis

Is there a single prior art reference that discloses:
- an EndoS2 mutant with D182Q
- plus the directional activity shift (or a close functional equivalent)
- plus coupling with activated glycan donors to GlcNAc acceptors

If not, challengers will pivot to obviousness:

Combine disclosure of:
- EndoS2 site-directed mutagenesis to alter hydrolysis/transglycosylation
- donor activation with glycan oxazolines
- GlcNAc acceptor engineering on antibodies
- then argue D182Q is a predictable substitution to obtain the phenotype

Claim construction pressures

“mutation at residue 182 is D I82Q” is unambiguous on the amino-acid substitution. Construction will turn on:
- mapping of residue numbering between sequences in the art and the patent’s SEQ IDs
residue windows (133–143 etc.) depend on sequence alignment.
activity terms (“lower/higher”) require assay comparability.

Key business implications

Enforcing scope concentrates on the enzyme mutant

The strongest leverage in litigation typically comes from the enzyme-definition structure:

D182Q in the mutant
specific residue-window mutation constraints
optional narrowing to explicit SEQ IDs (claim 4)

Downstream claims (claim 12) are depend-on-claim-1

A cancer-use claim that depends on claim 1 usually has less stand-alone value if claim 1 falls. For investors and R&D teams, the strategic target is enzyme/genotype freedom-to-operate, not indication design.

Donor/acceptor breadth increases commercial utility but can create validity pressure

Large donor and antibody acceptor lists increase practical adoption and commercial coverage. They also increase the risk of enablement or written-description challenges if the patent’s experimental record does not show performance across those many structures.

Key Takeaways

US 10,407,673 claims a glycoprotein engineering method using an EndoS2 mutant defined by D182Q at residue 182, additional mutations within specified residue windows, and a directional activity phenotype (lower hydrolysis, higher transglycosylation).
The most enforceable portions are claim 1’s genotype-function linkage and claim 4’s enumerated SEQ ID mutant sequences.
Claims 5–11 expand donor and acceptor scope broadly (glycan oxazolines; GlcNAc-containing acceptors; IgG acceptors; many named antibodies), which improves commercial coverage but can increase validity exposure if experimental support is narrow.
Claim 12 is a downstream cancer-use limitation that depends entirely on the claim-1 glycoprotein product.
For design-arounds, avoiding D182Q or shifting outside the specified residue windows and/or using a different activated donor class are the most direct paths.

FAQs

1) Is D182Q mandatory to fall within claim 1?

Yes. Claim 1 explicitly requires the mutation at residue 182 to be D182Q.

2) Does claim 4 expand or narrow the scope versus claim 1?

It narrows. Claim 4 limits the mutant to one of the explicitly listed SEQ ID NO sequences.

3) What is the role of glycan oxazolines in this patent?

Claim 5 limits activated donors to glycan oxazolines, tying the method to that donor activation mode rather than other activated glycan chemistries.

4) Does claim 12 cover any cancer therapy protein, or only those made by claim 1?

Only those “prepared by the method of claim 1,” since claim 12 is dependent on claim 1’s product.

5) Where are the likely strongest validity challenges likely to concentrate?

On whether the prior art already discloses the specific EndoS2 mutant genotype-to-function (including D182Q) and on whether the specification enables transglycosylation across the very broad donor and acceptor range recited in claims 6–11.

References

[1] US Patent 10,407,673 (claims and claim dependencies as provided in the prompt).

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Janssen Biotech, Inc.	REOPRO	abciximab	Injection	103575	December 22, 1994	10,407,673	2038-06-18
Genentech, Inc.	RITUXAN	rituximab	Injection	103705	November 26, 1997	10,407,673	2038-06-18
Hoffmann-la Roche Inc.	ZENAPAX	daclizumab	Injection	103749	December 10, 1997	10,407,673	2038-06-18
>Applicant	>Tradename	>Biologic Ingredient	>Dosage Form	>BLA	>Approval Date	>Patent No.	>Expiredate

Patent: 10,407,673

Summary for Patent: 10,407,673