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Patent landscape, scope, and claims: |
Scope and Claims Analysis of US Patent 7,122,566 (Metaxalone CYP450 Interaction Patient-Information Methods)
US 7,122,566 claims a patient- or clinician-facing method for using metaxalone that hinges on informing the patient about CYP450-mediated drug interactions and the resulting effects on plasma concentration, safety, and efficacy. The claim set is broad across multiple CYP isoforms and covers co-administration with substances that act as CYP substrates, inhibitors, or inducers, with explicit examples including warfarin, phenytoin/fosphenytoin, thioridazine, and theophylline. Independent claim 1 is a “learn-and-act” label/communication method, not a formulation or dosing regimen. The dependent claims then narrow to narrow therapeutic index drugs and to specific CYP isoforms and mechanistic roles (metaxalone as inducer/inhibitor/substrate).
What does US Patent 7,122,566 claim about metaxalone and CYP450 drug interactions?
Short answer: It claims a method of treating a patient with metaxalone that includes informing the patient or medical care worker that metaxalone affects a CYP isozyme and that coadministration with another CYP-active substance can change exposure and outcomes for one or both drugs.
Claim 1 (Independent): “Informing” method tied to CYP-mediated interaction risk
Claim 1 is structured as:
- Provide a patient with metaxalone for treating a condition.
- Inform the patient or a medical care worker that:
- metaxalone affects activity of a cytochrome P450 isozyme, and
- administration of metaxalone with a substance that affects activity of a cytochrome P450 isozyme can affect plasma concentration, safety, efficacy, or any combination thereof of metaxalone, the substance, or both.
Core claim elements
- Patient/clinical communication step: “informing the patient or a medical care worker.”
- Mechanistic anchor: metaxalone “affects activity” of a CYP isozyme.
- Interaction scope: coadministering metaxalone with another substance that also “affects activity” of a CYP isozyme.
- Outcome breadth: plasma concentration, safety, efficacy, or any combination, for metaxalone, the coadministered substance, or both.
Practical interpretation for enforcement
- Liability theory is not “metaxalone interacts in vivo,” but “use metaxalone in a way that includes the specified communication about CYP interaction consequences.”
- This is the kind of claim set that can be asserted against parties whose label, prescribing instructions, or REMS-style patient counseling matches the recited informational content, even without a new chemical entity.
Claim 2 to 4: Narrow therapeutic index co-medication and exemplars
- Claim 2: Substance is an active agent with a narrow therapeutic index.
- Claim 3: The narrow TI substance is a substrate of one or more listed CYP isoforms (CYP1A2, CYP3A4, CYP2B6, CYP2C19, CYP2D6, CYP2E1, CYP2C9).
- Claim 4: The narrow TI substrate is one of: warfarin, phenytoin, fosphenytoin, thioridazine, or theophylline.
Effect on scope
- Claim 2-4 substantially expand interaction coverage while using narrow-TI as a gating concept (high clinical salience).
- Claim 4 provides a deterministic list of drugs that are likely to be used as anchors in claim charts during litigation.
Claim 5 (Independent-alternative): CYP isozyme metabolizing metaxalone plus substrate/inhibitor/inducer scope
Claim 5 has a different information premise:
- It identifies the CYP isozyme metabolizing metaxalone as CYP1A2 or CYP2C19.
- It requires informing that administration of metaxalone and a substance that is a substrate, inhibitor, or inducer of CYP1A2 or CYP2C19 can affect plasma concentration, safety, efficacy, or any combination for metaxalone, the substance, or both.
Scope differences vs Claim 1
- Claim 1 is generic “metaxalone affects activity of a CYP isozyme.”
- Claim 5 is more specific: it ties metaxalone metabolism to a specific CYP (CYP1A2 or CYP2C19) and uses the explicit substrate/inhibitor/inducer triad.
Claims 6 to 13: Metaxalone as broad CYP-active + narrow TI + specific examples
Claim 6 recasts the “informing” content:
- Inform that metaxalone is an inhibitor, inducer, or substrate of a CYP isozyme.
- Inform that coadministration of metaxalone with a substance that is an inhibitor, inducer, or substrate of that CYP can affect plasma concentration, safety, or efficacy of the substance.
Claim 7 and 8 narrow:
- Claim 7: CYP isozyme is among CYP1A2, CYP3A4, CYP2B6, CYP2C19, CYP2D6, CYP2E1, CYP2C9.
- Claim 8: substance is an active agent with narrow therapeutic index.
Claims 9 to 12 define the narrow TI active agent in relationship to CYP:
- Claim 9: narrow TI substance is a substrate of listed CYP isoforms.
- Claim 10: narrow TI active agent is an inhibitor of the CYP isozyme.
- Claim 11: narrow TI active agent is an inducer.
- Claim 12: narrow TI active agent is a substrate.
Claim 13 repeats exemplars (warfarin, phenytoin, fosphenytoin, thioridazine, theophylline).
Claims 14 to 19: Explicit metaxalone role (inducer/inhibitor/substrate) and CYP targeting
- Claim 14: metaxalone is an inducer of the CYP isozyme.
- Claim 15: inducer relationship is with CYP1A2 or CYP3A4.
- Claim 16: metaxalone is an inhibitor of the CYP isozyme.
- Claim 17: inhibitor relationship is with CYP1A2, CYP2B6, CYP2C19, CYP2D6, CYP2C9, CYP2E1, or CYP3A4.
- Claim 18: metaxalone is a substrate of the CYP isozyme.
- Claim 19: substrate relationship is with CYP1A2 or CYP2C19.
Claims 20 to 22: Patient classification add-ons (musculoskeletal condition, human patient, receiving metaxalone)
- Claim 20: patient is a human patient.
- Claim 21: patient has a musculoskeletal condition.
- Claim 22: patient receiving metaxalone therapy.
How broad are the CYP isoforms and interaction directions covered by US 7,122,566?
Short answer: The patent uses two breadth mechanisms: (1) a wide list of CYP isoforms in multiple claims, and (2) multiple mechanistic roles (substrate/inhibitor/inducer) for both metaxalone and the co-medication, plus outcome language that covers concentration and clinical impact.
CYP isoforms explicitly enumerated
Across the claims you provided, the patent enumerates:
- CYP1A2
- CYP3A4
- CYP2B6
- CYP2C19
- CYP2D6
- CYP2E1
- CYP2C9
Where coverage appears
- Claim 3 and Claim 7: listed isoforms for narrow-TI substrate and for general CYP isozyme selection.
- Claim 5: CYP1A2 or CYP2C19 as the metabolizing isozyme(s) for metaxalone.
- Claim 15 and Claim 19: CYP1A2/CYP3A4 (inducer) and CYP1A2/CYP2C19 (substrate).
- Claim 17: broad inhibitor list excluding any single CYP from the enumerated set.
Mechanistic interaction roles
The claim set covers:
- Metaxalone: affects activity (Claim 1), is inhibitor/inducer/substrate (Claim 6), with explicit metaxalone roles (Claims 14-19).
- Coadministered substances: affect activity (Claim 1), are substrate/inhibitor/inducer (Claim 5), and are inhibitor/inducer/substrate of the relevant CYP (Claim 6).
Outcome language
- Claim 1 includes plasma concentration, safety, and efficacy in a flexible “or any combination” construction.
- Claim 6 narrows slightly to plasma concentration, safety, or efficacy of the substance, but still remains broad.
Enforcement consequence
- A defendant arguing “no clinically meaningful effect” is still exposed because the claims do not require magnitude thresholds, only that coadministration “can affect” the specified outcomes.
What is the practical claim scope: does US 7,122,566 cover dosing, formulations, or labeling communication?
Short answer: It is a method-of-use claim anchored on informing the patient or medical care worker about CYP-mediated interaction risk when prescribing metaxalone.
Not claimed (based on your claim text)
- No formulation steps.
- No manufacturing methods.
- No specific dose amount or titration schedule.
- No requirement for measured PK outcomes.
- No requirement of a particular clinical endpoint beyond generic safety/efficacy notions.
Claimed
- A treatment method with an embedded informational communication step.
- A mechanistic statement about metaxalone’s CYP relationship.
- A warning-style statement that coadministration with CYP-active substances can change exposure and clinical outcomes.
Implication for design-around
- Changing dosing or formulation alone likely does not avoid literal scope if the informational content remains in prescribing practice.
- Shifting patient communication away from the claimed statements could be a potential strategy, though this claim style often aligns with label and standard-of-care counseling.
Which co-medications are explicitly captured (warfarin, phenytoin, fosphenytoin, thioridazine, theophylline)?
Short answer: Claim 4 and Claim 13 expressly list warfarin, phenytoin, fosphenytoin, thioridazine, and theophylline as narrow therapeutic index active agents.
Explicit narrow therapeutic index exemplars
- Warfarin
- Phenytoin
- Fosphenytoin
- Thioridazine
- Theophylline
How they function inside the claims
They appear as:
- The narrow therapeutic index “substance” (Claim 4) and as the narrow TI active agent (Claim 13) in lists that tie to CYP substrates and, in related dependent claims, can also involve inhibitor/inducer roles depending on which dependent chain is asserted.
Litigation use
- These exemplars typically serve as high-probability claim chart anchors because they are well-known CYP substrates and clinically monitored drugs.
How do dependent claims narrow or expand claim 1’s risk statement?
Short answer: The dependent claims add (a) narrow therapeutic index and (b) explicit mechanistic role assignments and specific CYP isozyme selections, creating multiple litigation pathways under the same “informing” framework.
Narrowing moves
- Narrow TI restriction (Claims 2 and 8) reduces the universe of co-medications.
- CYP subset limitations in certain claims:
- CYP1A2/CYP2C19 for metaxalone metabolizing isozyme (Claim 5).
- CYP1A2 or CYP3A4 for inducer role (Claim 15).
- CYP1A2 or CYP2C19 for substrate role (Claim 19).
Expansion moves
- Claim 6 broadens by allowing metaxalone to be inhibitor/inducer/substrate and also allowing the co-medication to be inhibitor/inducer/substrate.
- Claim 7 restores broad isozyme enumerations (CYP1A2 through CYP2C9 list).
“Any combination thereof” breadth
- Claim 1’s flexible “plasma concentration, safety, efficacy or any combination” gives the patentee multiple theory angles.
What would an alleged infringement theory need to prove under this claim language?
Short answer: The infringement theory would focus on whether the accused use includes the specified informational communication and whether it covers the CYP-active co-medication scenario described.
Facts typically required (from the claims you provided)
- A patient is provided metaxalone for a musculoskeletal or human patient context (depending on the asserted claims).
- A patient or medical care worker is informed that:
- metaxalone affects activity of a CYP isozyme (Claim 1) or that metaxalone is inhibitor/inducer/substrate (Claim 6), and
- coadministration with a CYP-active substance can affect plasma concentration, safety, efficacy, or combination.
- The co-medication is within the dependent-claim constraints if asserted:
- narrow therapeutic index (Claims 2, 8)
- CYP substrate/inhibitor/inducer status (Claims 3, 5, 6 and related)
- specific drug list if the chain uses Claims 4 or 13.
Key structural point
- If the “informing” step is not met, the method claim may not be satisfied even if CYP interaction exists. That makes real-world label language and counseling practices central to infringement analysis.
Is US 7,122,566 likely to be listed in the Orange Book, and what does that mean for generic entry risks?
Short answer: This analysis cannot be completed from the information provided. The claim text alone does not establish Orange Book listing status, reference product, listed patents, or FDA regulatory linkage.
What patent landscape exists around metaxalone CYP interaction patient-information claims?
Short answer: This analysis cannot be completed from the information provided. A landscape requires patent family identification, continuations/divisionals, related method-of-use patents, prosecution history, and citations/overlaps.
Key Takeaways
- US 7,122,566 is a method-of-use patent anchored on informing the patient or a medical care worker about CYP450-mediated drug interaction risk when using metaxalone.
- The claims are mechanistically broad: metaxalone “affects activity” of CYP isoforms and can be an inhibitor/inducer/substrate, while co-medications can be substrates/inhibitors/inducers.
- The CYP coverage includes CYP1A2, CYP3A4, CYP2B6, CYP2C19, CYP2D6, CYP2E1, and CYP2C9, with tighter subsets in certain dependent claim chains.
- Narrow therapeutic index drugs are expressly captured, including warfarin, phenytoin, fosphenytoin, thioridazine, and theophylline.
- The claims focus on “can affect” outcomes (plasma concentration, safety, efficacy) without magnitude thresholds, but still require the recited informing step for literal coverage.
FAQs
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Does US 7,122,566 require actual patient harm or a measured PK interaction?
The claims use “can affect,” and require informing, not demonstrated harm or quantified PK change.
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Can the patent cover coadministration where the interaction involves an inducer rather than an inhibitor?
Yes, depending on the asserted dependent chain because claims include inducer relationships for the co-medication and, in some claims, for metaxalone.
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Is metaxalone required to be a substrate in all versions of the claim set?
No. The independent claim 1 requires only that metaxalone affects activity of a CYP isozyme. Separate dependent claims explicitly require metaxalone to be substrate/inhibitor/inducer.
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What is the significance of the “narrow therapeutic index” limitation?
It limits certain dependent claim pathways to high-risk co-medications, narrowing the claim scope around drugs like warfarin and theophylline.
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Do musculoskeletal condition and human patient limitations materially narrow infringement exposure?
They apply only if those dependent claims are asserted; the independent claim 1 broadly covers “patient” language as provided in the dependent chain structure you provided.
References
No sources were cited because the prompt provided only the claim text and did not include bibliographic details, prosecution documents, Orange Book listings, FDA status, or litigation records.
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