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Patent landscape, scope, and claims: |
US Patent 8,476,284: Scope, Claim Architecture, and Patent Landscape for Btk-Targeting Lymphoma Treatment
What does US 8,476,284 claim cover at a high level?
US Patent 8,476,284 claims methods of treating lymphoma by administering a covalent (irreversible) Bruton's tyrosine kinase (BTK)-binding compound. The claim scope is built around (i) a broad “Formula (A)” chemical genus and (ii) a lymphoma-use therapeutic method, with dependent claims tightening to oral dosing and mechanistic covalent bonding to BTK (cysteine).
Core independent claim concept (Claim 1):
- Treatment method for lymphoma in a subject
- Administer a therapeutically effective amount of a compound of Formula (A)
- Formula (A) is defined by:
- A = N
- R1 = phenyl-O-aryl or phenyl-S-aryl
- R2, R3 = H or lower alkyl or substituted lower alkyl
- R4 = L3-X-L4-G (multi-part linker/building block system)
- X = an optional covalent/connection unit with a wide list including heteroaryl/aryl-type linkers and multiple functional group options
- G = a second linker fragment containing the sulfonamide / amide / nitrile / nitro / heteroatom-containing motifs via R6/R7/R8 (default H) and R9/R10/R11 substituent rules
- Includes pharmaceutically acceptable salts
Dependent claims expand enforceable method coverage into dosing form and BTK covalent mechanism:
- Claim 2: oral administration
- Claim 3: compound bonds to BTK irreversibly
- Claim 4: compound forms a covalent bond to BTK
- Claim 5: covalent bond to BTK cysteine residue
- Claims 6-9: specify Formula (D) structural subsets (with specific ring systems and “Z” warhead options)
- Claims 10-11: cover additional structural variants (text truncated in the prompt, so only claim concept is retained)
How broad is the chemical genus in Claim 1 (Formula A)?
Claim 1 uses a very large combinatorial genus. It does not limit to a single known BTK inhibitor scaffold; it defines a permissive architecture through variable selection rules (especially on R4 = L3-X-L4-G, and within X and L4, and within G through R9/R10/R11).
Key genus levers that expand scope
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R1 flexibility
- “phenyl-O-aryl or phenyl-S-aryl” permits either oxygen or sulfur linkages between phenyl and aryl.
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R4 modularity
- R4 = L3-X-L4-G, where:
- L3 is optional and, when present, can be a bond or various carbon/sp3/sp/sp2 fragments (alkyl/cycloalkyl/alkenyl/alkynyl).
- X is optional; when present, X can be a bond or any one of many linker/covalent-connecting group types (including heteroaryl, aryl, and many carbonyl/sulfonyl/amide/amine-like connection patterns).
- L4 is optional; when present, L4 can be diverse hydrocarbon or aromatic/heteroaromatic linkers.
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G warhead and substituent variability
- G definition includes a set of substituent rules:
- R9 (lower alkyl or lower cycloalkyl)
- R10 (lower alkyl or lower cycloalkyl) with the possibility that two R10 groups together can form a 5-, 6-, 7-, or 8-membered heterocycle
- R11 options include sulfonamide substituents, carboxamide, cyano, nitro, and heteroaryl/heteroalkyl.
-
Salt coverage
- The claim includes pharmaceutically acceptable salts, expanding protection to salt forms and potential formulation variants.
Net effect
Even though Claim 1 uses structured variables, the breadth is driven by:
- optional linker presence (L3, X, L4 can be absent),
- large permitted sets for X, L4, and G substituent patterns,
- open inclusion of heteroaryl and aryl in multiple positions.
What functional mechanism is required for infringement (method claims)?
The independent method claim (Claim 1) is structurally defined but not explicitly mechanism-limited in the text you provided. The mechanistic narrowing occurs in dependent claims:
- Claim 3: BTK binding is irreversible
- Claim 4: compound forms a covalent bond to BTK
- Claim 5: covalent bond targets the cysteine residue of BTK
Implication for enforcement
- A design-around that uses the same general scaffold but loses covalent/irreversible BTK binding would likely avoid dependent-claim coverage (Claims 3-5).
- However, Claim 1 (if the structure fits Formula A) can still capture lymphoma treatment methods even if the BTK effect is not covalent, depending on how courts interpret whether the chemical genus necessarily implies covalent irreversibility (dependent claims indicate the drafter’s intended mechanism, but independent claim text controls infringement analysis).
How does Claim 6 (Formula D) narrow the scope?
Claims 6-9 carve out a sub-genus (“Formula (D) or salts”) with tighter structural constraints:
Formula (D) key parameters stated
- La is O or S
- Ar is unsubstituted phenyl
- Y is a ring selected from:
- 4-, 5-, 6-, or 7-membered cycloalkyl, or
- azetidinyl, pyrrolidinyl, piperidinyl, or azepanyl
- Z is selected from:
- C(═O), O C(═O), NHC(═O), S(═O)x, or NHS(═O)x, where x = 2
- R6/R7/R8 each independently H, or
- R7 and R8 together form a bond and R6 is H
Dependent narrowing
- Claim 7: specifically La = O
- Claim 8: Z is C(═O), NHC(═O), or S(═O)2
- Claim 9: R6/R7/R8 are each H
Practical read
Formula D is consistent with a BTK covalent-inhibitor design space that varies:
- ring size at Y,
- oxygen vs sulfur at La,
- carbonyl/sulfonyl-type groups at Z.
What does “oral administration” add (Claim 2)?
Claim 2 adds a simple but enforceable limitation:
- Oral dosing of the Formula (A) compound for lymphoma treatment.
This can matter if competitors pursue parenteral routes (or develop formulations that change route-of-administration).
How does Claim 10-11 expand coverage beyond Formula D?
The prompt truncates the actual structure for Claim 10 (“has the structure of Formula (D) or a pharmaceutically acceptable salt thereof: wherein…” appears in Claim 6, and Claim 10 shows “wherein: or a pharmaceutically acceptable salt thereof” with an omitted structure). Claim 11 continues with “A method… administering… a compound having the structure” and is also truncated.
What can be reliably concluded from the text provided
- Claim 10 and Claim 11 likely define additional specific structural embodiments beyond Formula (A) and Formula (D), but the exact boundaries are not fully legible from the provided excerpt.
What is the likely patent landscape around this claim set (Btk covalent inhibitors for lymphoma)?
Your excerpt describes a typical covalent BTK inhibitor method-of-use posture. In the US, this space is dominated by overlapping families that generally fall into:
- (1) early BTK covalent inhibitor core chemistries and warheads,
- (2) specific improvements in substituent patterns and ring variants,
- (3) method-of-treatment claims (including lymphoma),
- (4) formulation and route-of-administration.
Given the explicit mechanism language in dependent claims (irreversible, covalent, cysteine residue), this patent is positioned to attack products that:
- are used for lymphoma indications, and
- use a covalent BTK mode of action.
Actionable landscape approach (based on the claim language you provided):
- Expect the most direct overlap with other US patents claiming:
- covalent BTK inhibitors,
- specific warhead-bearing scaffolds that react with BTK cysteine,
- lymphoma treatment methods.
Where is the highest litigation leverage in US 8,476,284?
1) Dependent claims 3-5 (BTK covalent irreversibility)
These provide crisp infringement hooks for products marketed as covalent BTK inhibitors:
- irreversibly binds BTK
- forms a covalent bond
- covalently bonds to BTK cysteine
2) Dependent claim 2 (oral dosing)
If a competitor’s label and clinical program use oral BTK inhibition in lymphoma, Claim 2 tightens coverage.
3) Sub-genus claims 6-9 (Formula D)
These are narrower and likely correspond to commercially relevant embodiments with specific ring and functional-group settings.
Design-around signals embedded in the claim language
A party seeking to avoid coverage would focus on:
- breaking coverage of Formula A structural definitions (R1, R4 architecture, G substituent sets),
- avoiding BTK covalent cysteine bonding (to escape Claims 3-5),
- shifting away from oral administration (to avoid Claim 2),
- using chemical alternatives that land outside Formula D parameters (La, Z, Y).
Key Takeaways
- US 8,476,284 is a lymphoma method-of-treatment patent centered on a broad chemical genus (Formula A) that allows extensive variation in linker and substituent definitions.
- Enforcement leverage increases sharply in dependent claims requiring irreversible covalent BTK binding, specifically cysteine residue targeting.
- Claims 6-9 narrow to a structured Formula D sub-genus, controlling ring identity (Y), oxygen vs sulfur (La), and carbonyl/sulfonyl type functionality (Z).
- Practical scope is strongest against therapies that match: (i) Formula A structure, (ii) oral lymphoma treatment use, and (iii) covalent BTK cysteine mechanism.
FAQs
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Is Claim 1 limited to covalent BTK inhibitors?
Claim 1 is structural (Formula A) and does not explicitly require covalent BTK in the text you provided. Covalent/irreversible/cysteine targeting appears in dependent claims 3-5.
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What does Claim 5 add over Claim 4?
Claim 5 specifies the covalent interaction is with the cysteine residue of BTK.
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What limitation does Claim 6 introduce?
Claim 6 limits the administered compound to a Formula (D) subset with defined selections for La, Ar, Y, and Z.
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Does Claim 2 cover oral dosing only?
Yes. Claim 2 specifically requires oral administration of the Formula (A) compound for lymphoma treatment.
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How can companies reduce risk under this patent?
Risk reduction focuses on (i) structural non-alignment with Formula A and Formula D sub-genus parameters, and (ii) ensuring the mechanism does not meet dependent-claim covalent BTK cysteine requirements, and (iii) avoiding the oral route if the commercial model differs.
References
[1] United States Patent 8,476,284 (claim excerpt provided in prompt).
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