Patent 9,175,331 (US 9,175,331): Scope and claims map for EZH2 Y641 mutant cancers and MDS, plus the US patent landscape
Executive summary: US 9,175,331 is a US method-of-treatment patent that claims administering an EZH2 inhibitor to subjects whose EZH2 contains a substrate-pocket domain mutation at Y641 (specifically Y641F, Y641H, Y641N, or Y641S) for treating cancer or myelodysplastic syndromes (MDS). The claim scope is constrained by (i) a defined EZH2 genotype, (ii) the mutation being in the substrate pocket domain per stated sequence definitions, and (iii) an EZH2 inhibitor administration concept. Additional dependent claims narrow to a functional biomarker axis (increased H3K27 trimethylation and/or inhibition of conversion to trimethylated H3K27) and to certain lymphoma subtypes.
What claims does US 9,175,331 cover for EZH2 Y641F/H/N/S mutant cancer and MDS?
Core independent claim (Claim 1) in plain structure:
- Patient population: subject has an EZH2 mutation in the substrate pocket domain corresponding to a mutation at amino acid position Y641 of EZH2 (as defined by SEQ ID NO: 1 and SEQ ID NO: 6).
- Permitted substitutions at Y641: Y641F, Y641H, Y641N, Y641S (wild-type tyrosine Y replaced by F/H/N/S).
- Indication: treating cancer or MDS.
- Therapeutic intervention: administer a therapeutically effective amount of an EZH2 inhibitor (or pharmaceutically acceptable salt).
Claim 1 is a genotype-defined method-of-treatment that does not limit:
- to a particular drug molecule, modality, or dosing schedule;
- to a particular route;
- to a particular line of therapy (front-line vs relapsed);
- to a required biomarker status beyond the genotype constraint (biomarker appears in dependent claims).
How do Claims 2 and 3 expand the biomarker linkage (H3K27me3 biology)?
- Claim 2: narrows to subjects where the EZH2 mutation increases EZH2 trimethylation of Lys27 of histone H3 (H3-K27).
- Claim 3: reframes Claim 1 with a biomarker premise: the subject has an increased level of trimethylated H3-K27 as a result of the EZH2 mutation defined in Claim 1, and administers an EZH2 inhibitor.
Practical scope effect:
Claims 2 and 3 add an explanatory/functional limitation that can matter in infringement arguments where parties dispute whether Y641 mutants drive H3K27me3 elevation in the clinical context, or where a challenger tries to treat “Y641 mutant” as not universally linked to increased H3K27me3.
What does Claim 4 require about the mechanism (inhibiting conversion to H3K27 trimethylation)?
- Claim 4: dependent on Claim 1 or 3, requires that the EZH2 inhibitor inhibits conversion of H3K27 to trimethylated H3K27.
Practical scope effect:
This is a mechanism-of-action limitation. It reduces the risk that an accused product is argued to act on EZH2 indirectly or through non-catalytic effects without affecting the specific conversion step described.
How specific is the EZH2 mutation element (Y641, substrate pocket domain, SEQ IDs)?
Mutation definition is the gate.
The method is limited to subjects with an EZH2 mutation in the substrate pocket domain with a Y641 substitution selected from: F, H, N, S.
What is included vs excluded by the claim language?
Included (by explicit listing):
Excluded (by explicit listing or by omission):
- Other Y641 substitutions not listed (example: Y641W, Y641A, etc.).
- Other EZH2 mutations outside the substrate pocket domain (even if near Y641).
- Wild-type EZH2.
- Mutations that do not map to the specified sequence definitions (SEQ ID NO: 6 and its relationship to SEQ ID NO: 1).
Key technical nuance: the claim ties “Y641” to amino acid position 641 of SEQ ID NO: 1, and further requires that SEQ ID NO: 6 comprises a mutation at amino acid position Y641. That can become central in claim construction disputes on sequence numbering and domain boundaries.
What types of cancer are covered (and which are expressly named)?
Claim 7: which lymphoma types are explicitly in scope?
- Claim 7 depends on Claim 1 or 3 conceptually and requires cancer is lymphoma.
- Claim 8 (as provided) specifies lymphoma selected from:
- non-Hodgkin lymphoma
- follicular lymphoma
- diffuse large B-cell lymphoma
Practical scope effect:
Even if independent claim language covers “cancer or MDS” broadly, the lymphoma dependent claims lock in particular clinical targets. For enforceability, this can help align with clinical trial populations and label language if an EZH2 inhibitor is tested or prescribed in lymphoma subtypes.
What are the most commercially relevant scope boundaries for infringement analysis?
1) Drug identity is not limited
The claims do not name a specific EZH2 inhibitor compound. They cover “an EZH2 inhibitor”. This broad definition expands potential infringement coverage to both:
- early-stage EZH2 inhibitors,
- established EZH2 inhibitors,
- and any small molecule meeting the claim’s functional MOA concept in Claim 4.
2) Patient selection is the main limiting factor
The strongest “switch” is genotype:
- if a subject does not carry the defined EZH2 Y641 substrate-pocket mutations, the method claims are not directed to them.
3) Mechanism limitations matter in the margin
- If an accused EZH2-targeting agent is argued to not inhibit conversion of H3K27 to trimethylated H3K27 (Claim 4), the dependent coverage can narrow sharply.
4) Biomarker disputes can narrow dependent claims
- Claims 2/3 introduce a functional “increased H3K27me3 due to the mutation” element. Litigation can hinge on whether the Y641 mutations in the relevant disease context measurably increase H3K27 trimethylation and whether the accused patient population meets that functional limitation.
How would US 9,175,331 likely map into an EZH2-inhibitor development and labeling timeline?
The claim is genotype-defined and biomarker-connected in a way that is consistent with:
- enrichment strategies in clinical trials for epigenetic modifiers,
- companion diagnostics aimed at EZH2 Y641 variants,
- and mechanistic confirmation via H3K27me3 measurements.
Risk to generics/biosimilar-style entries:
Because the claims are method-of-treatment claims, the infringement hook is typically patient-directed use. Commercial risk sits with:
- prescribing physicians,
- product labeling if it authorizes use in genotype-positive patients,
- and promotional materials tying the drug to the claimed population.
What other US patent categories typically coexist around genotype-defined EZH2 Y641 targeting?
Even without enumerating a full estate from record evidence, the typical patent landscape around a specific EZH2 mutation and inhibitor class includes:
- Compound/active ingredient patents (EZH2 catalytic inhibitors), likely covering chemical structures, substitutions, and salt forms.
- Formulation patents (oral solid, capsule, tablet, crystalline forms, polymorphs, excipients).
- Method-of-treatment patents (genotype-defined or biomarker-defined indications like Y641 mutant disease).
- Combination therapy patents (EZH2 inhibitor plus another agent, such as immunotherapies, DNA damage agents, or cytotoxics).
- Diagnostic or companion diagnostic patents (assays detecting EZH2 Y641 and linking to treatment).
- Resistance and monitoring patents (secondary mutations, adaptation pathways, or H3K27me3 monitoring methods).
For US 9,175,331 specifically, the claim set you provided indicates the patent is anchored to clinical use rather than chemical identity.
How does US 9,175,331 compare with other EZH2 Y641 mutant patents in scope (genotype vs mechanism vs disease class)?
Scope driver hierarchy (most to least constraining):
- Genotype constraint: EZH2 substrate pocket Y641 substitutions limited to F/H/N/S
- Disease class: cancer or MDS; dependent lymphoma types limited further
- Mechanistic/biomarker constraints: increased H3K27 trimethylation (Claims 2 and 3) and inhibition of conversion (Claim 4)
This structure is typical of a method-of-treatment patent intended to survive challenges aimed at overbreadth on drug identity. The patent is designed to say: regardless of which EZH2 inhibitor you use, if the patient carries the specified Y641 mutant EZH2 and the therapy uses EZH2 inhibitory activity that prevents H3K27 trimethylation, then treating the indicated diseases falls within the claim.
What patent litigation or Orange Book status issues are implicated by this claim type?
- Orange Book: method-of-treatment claims are often listed with an NDA/ANDA only if they are connected to patentable information recognized for Orange Book listing. Infringement would depend on whether the relevant product is labeled and used in the genotype-defined manner.
- Paragraph IV risk profile: if an ANDA challenges an Orange Book-listed patent that includes method-of-treatment claims, the risk focuses on whether the ANDA carve-out and label design avoid instructions for Y641 mutant patient use.
(Determining exact Orange Book listings, Paragraph IV challenges, settlements, and assignee/enforcement status requires docket- and Orange-Book-level record evidence that is not present in the information provided.)
Key Takeaways
- US 9,175,331 is a genotype-defined method-of-treatment: administer an EZH2 inhibitor to subjects with EZH2 substrate pocket domain mutations at Y641 limited to Y641F, Y641H, Y641N, and Y641S for cancer or MDS.
- The claims broaden across “any EZH2 inhibitor” but narrow across patient selection and, in dependents, H3K27me3 functional biology and mechanism (inhibiting conversion to trimethylated H3K27).
- Lymphoma dependent claims further specify non-Hodgkin lymphoma, follicular lymphoma, and diffuse large B-cell lymphoma.
- Enforceability leverage is highest where the treated population is enriched for EZH2 Y641 mutants and where clinical practice aligns with EZH2 inhibitory MOA and H3K27me3 effects.
FAQs
- Does US 9,175,331 cover EZH2 inhibitors even if they do not explicitly label Y641-mutant treatment?
- Which dependent claims are most vulnerable to arguments that Y641 mutants do not increase H3K27 trimethylation in vivo?
- How does the claim language “substrate pocket domain” constrain claim interpretation for EZH2 variants near, but not in, the defined domain?
- Would a label directing treatment only for “EZH2 Y641 mutant” cancers automatically create infringement exposure for generic entrants?
- What drug mechanism distinctions matter most for Claim 4’s “inhibits conversion of H3K27 to trimethylated H3K27” limitation?
References
- User-provided claim text for US 9,175,331 (claims 1-8 as supplied in the prompt).
