US Patent 9,339,499 (Hydrocodone Bitartrate ER): Scope, Claim Strength, and US Patent Landscape for Hepatic-Impairment Pain Treatment
Executive summary
- US Drug Patent 9,339,499 claims method-of-treatment protection for oral hydrocodone bitartrate extended-release (ER) in patients with mild or moderate hepatic impairment, anchored to quantified exposure limits (AUC0-inf and Cmax) and specific ER formulation release mechanics.
- The claims are built around three limiting pillars: (1) patient phenotype (mild/moderate hepatic impairment), (2) exposure-risk quantification using predetermined AUC0-inf and Cmax percent caps vs non-impairment, and (3) (in dependent claims) dose strength ranges and ER/in-ER immediate-release composition and dissolution behaviors.
- Practical freedom-to-operate hinges on whether a competitor’s hydrocodone bitartrate ER product (i) is dosed to hepatic-impaired patients without dose adjustment and (ii) produces hydrocodone exposure that falls inside or outside the claimed percent increases and/or Cmax/AUC ranges, plus whether formulation architecture matches claimed immediate-release bead + ER bead proportions and release/dissolution windows.
What patents protect hydrocodone bitartrate extended-release methods for patients with mild or moderate hepatic impairment?
Answer (claim scope): US 9,339,499 covers US methods of treating pain in mild or moderate hepatic impairment using an oral hydrocodone bitartrate ER dosage unit (hydrocodone bitartrate is the only active ingredient), where the product’s in vivo hydrocodone exposure in hepatic impairment does not exceed specified increases relative to non-impairment controls.
Independent claim architecture (Claim 1)
Claim 1 is the broadest claim you provided. It requires, in combination:
- Indication/patient population: patient with mild or moderate hepatic impairment.
- Drug: an oral dosage unit with hydrocodone bitartrate as the only active ingredient.
- Dosage form: extended release formulation of hydrocodone bitartrate.
- PK guardrails:
- Mild hepatic impairment: AUC0-inf increase ≤ 14%
- Moderate hepatic impairment: AUC0-inf increase ≤ 30%
- (Later dependent claims further constrain Cmax and specify additional numeric windows.)
Claim 1 is a method claim with an “exposure limitation.” That creates a litigation posture where infringement pivots on whether a competitor’s administered ER product, in the accused clinical context, yields PK outcomes meeting the stated caps.
Dependent claim “tightening” inside Claim 1
- Dose strength dependency (Claims 2–3): ≥15 mg; or specifically 20/30/40 mg.
- IR/ER hybrid architecture (Claims 4–6):
- Claim 4: ER dosage unit further includes an immediate-release formulation.
- Claim 5: split by weight: ER 75%–85% and IR 15%–25% of total hydrocodone.
- Claim 6: dual bead populations: first beads = IR, second beads = ER.
- Cmax caps (Claims 7–8):
- Mild hepatic impairment: Cmax increase cap can be ≤25% (Claim 7) or ≤9% (Claim 8).
- Moderate hepatic impairment: Cmax increase cap can be ≤30% (Claim 7) or ≤14% (Claim 8).
- Hard numeric PK windows (Claims 9–15):
- Baseline non-impairment AUC0-inf per 20 mg: *~300–500 ngh/mL** (Claim 9).
- Mild hepatic AUC0-inf per 20 mg: ~300–570
- Moderate hepatic AUC0-inf per 20 mg: ~300–700
- Subsequent claims narrow the ranges further for the three populations (Claims 10–12) and for Cmax (Claims 13–15).
Additional independent claims directed to “no dose adjustment” (Claims 17–20)
These claims are separate method formulations that focus on dosing practice rather than only ER PK caps.
- Claim 17: mild hepatic impairment, starting dose not adjusted vs non-impairment.
- Claim 19: moderate hepatic impairment, starting dose not adjusted vs non-impairment.
- Claims 18 and 20: starting dose strengths 15/20/30/40 mg.
Business implication: a product can potentially argue non-infringement by showing that its prescribing information, titration logic, or actual dosing practice in hepatic impairment includes dose adjustment, or that the measured PK differs from the claimed exposure-limiting envelope.
How broad are the scope and claims of US Patent 9,339,499, and what does infringement require?
Answer (scope): US 9,339,499 requires a combined match of (i) mild or moderate hepatic impairment, (ii) oral hydrocodone bitartrate ER as only active ingredient, and (iii) PK exposure results meeting specified percent increases and/or absolute AUC/Cmax windows (depending on which claim is asserted).
What does “release profile” mean in claim terms?
From your claim set, the patent uses two kinds of constraints:
- In vivo exposure constraints: AUC0-inf and Cmax percent increases relative to non-impairment, and/or absolute numeric windows per 20 mg dose.
- In vitro dissolution/release behavior (Claim 16): a specific USP dissolution apparatus buffered at pH 6.8, with defined release percentages over time.
Claim 16 adds an in vitro/dissolution gate (technical dependent claim)
Claim 16 requires:
- release about 10%–30% in first hour
- release about 60%–98% during first 12 hours
- in USP dissolution apparatus buffered at pH 6.8
Infringement posture: For products with different hydrophilic/hydrophobic matrix systems or different ER bead coatings, Claim 16 can become a formulation-level differentiator that supports non-infringement if dissolution curves fall outside the constrained release windows.
How many dependent claim branches materially narrow infringement risk for competitors?
Answer: At least five dependent-claim clusters can materially narrow infringement:
- Strength range requirements (Claims 2–3, 18, 20).
- Presence of immediate-release fraction (Claim 4).
- IR/ER weight split and bead population architecture (Claims 5–6).
- Cmax percent increase caps (Claims 7–8).
- Absolute AUC/Cmax numeric windows per 20 mg (Claims 9–15).
- Dissolution/release profile window in pH 6.8 (Claim 16).
Practical inference for landscape strategy: if a competitor’s ER formulation is similar but its PK in hepatic impairment does not stay within the ≤14% AUC (mild) or ≤30% AUC (moderate) bounds, it weakens Claim 1 coverage. If it stays within the AUC bounds but has higher Cmax, Claim 7/8 become the relevant battleground. If it stays within both AUC and Cmax but its dissolution kinetics differ, Claim 16 provides another non-infringement axis.
When does US 9,339,499 lose enforceability, and what matters for exclusivity vs patent term?
Answer: No enforceability or expiration date can be derived from the claims text alone. A full term analysis requires filing date, priority chain, and any patent term adjustment and patent term extension events. The constraints you provided are insufficient to compute a calendar expiration or last day of enforceability.
What patent claim elements most strongly constrain design-around options?
Answer: The tightest constraints are the PK exposure caps and the patient phenotype.
PK caps are “result-based” and hard to escape without clinical evidence
- Mild hepatic impairment AUC0-inf increase cap: 14%
- Moderate hepatic impairment AUC0-inf increase cap: 30%
- Cmax caps vary by dependent claim: 25% / 30% or 9% / 14%
- Absolute windows per 20 mg: AUC0-inf and Cmax ranges (Claims 9–15)
Design-around reality: A “different ER formulation” may still infringe if it delivers the same exposure outcome within the claim bounds. Conversely, a formulation that increases AUC0-inf beyond the caps can be positioned as non-infringing for the relevant claim(s), but that also risks clinical safety and label acceptance.
“Starting dose not adjusted” claims raise an evidence and label-following question
Claims 17 and 19 require that the starting dose is not adjusted vs non-hepatic impairment. That can turn on:
- clinical protocols and prescribing behavior in hepatic impairment
- labeling language or guideline adoption
- the dosing comparison basis used in the method
What formulations are protected by US 9,339,499? ER-only or IR/ER hybrid?
Answer: Claim 1 covers ER formulation. It does not require an IR component in the independent claim you provided. However:
- Claim 4–6 specifically protect an IR/ER hybrid with defined weight split (75%–85% ER; 15%–25% IR) and bead populations.
Formulation sub-scope matrix
| Claim cluster |
Formulation requirement |
Competitive relevance |
| Claim 1 |
ER hydrocodone bitartrate (only active ingredient) |
Broad method coverage; key hinge is PK caps |
| Claims 4–6 |
ER + immediate-release fraction; IR/ER weight split; bead populations |
Narrower but useful for architecture-based design-arounds |
| Claim 16 |
USP dissolution pH 6.8 release profile |
Narrower; formulation curve-based differentiator |
How does US 9,339,499 compare with other hydrocodone ER hepatic impairment patents (US landscape logic)?
Answer: The claim set you provided is unusually specific to hepatic impairment exposure limits rather than generic ER technology. In the US hydrocodone ER space, landscape typically clusters by:
- ER matrix/bead technology (composition/manufacturing patents)
- PK safety and dose-adjustment methodologies (method-of-use patents)
- pediatric, renal impairment, and hepatic impairment labeling-aligned exposure studies (often method claims)
But a full comparative landscape requires identifying related patents that cite or share priority with US 9,339,499, and matching those to FDA studies. Your prompt includes only the claims, not the patent family, assignees, or citations.
Because those bibliographic inputs are not present here, no defensible “other patents” list can be produced without fabricating numbers.
What Orange Book status does US 9,339,499 have for hydrocodone bitartrate ER?
Answer: Orange Book status depends on listing-specific data (drug product, NDA, listed patents, claim-to-product mapping, and expiration dates). The claims text does not identify:
- the relevant NDA/ANDA
- the labeled strength(s) and dosage forms
- the Orange Book listing mapping for US 9,339,499
No accurate Orange Book status can be stated from the provided information alone.
What generic entry risks exist for hydrocodone bitartrate ER using hepatic impairment exposure claims?
Answer: Risk is highest where:
- a generic filer submits an ER hydrocodone bitartrate product that produces hepatic impairment PK within the claimed caps, and
- litigation is pursued against method-of-use infringement based on “administering” practices consistent with the claims.
Lower risk where:
- the generic’s formulation shifts exposure such that hepatic AUC0-inf increases exceed 14% (mild) or 30% (moderate), or
- its prescribing information requires dose adjustment in hepatic impairment (undercutting “starting dose not adjusted” claims).
In US practice, method claims are often litigated with a mix of label-driven evidence and PK bridging and/or trial data. This claim set’s exposure gates make a generic’s hepatic impairment PK package central.
What Paragraph IV strategy would target US 9,339,499 claims (if asserted)?
Answer: A Paragraph IV strategy tied to these claims would focus on:
- non-infringement by arguing the generic does not meet the AUC0-inf and/or Cmax caps in hepatic impairment under the claimed conditions, and
- invalidity arguments focused on whether the claim’s PK thresholds were supported by the disclosure and were not obvious over known hydrocodone ER hepatic exposure knowledge.
However, without the patent specification, prosecution history, family members, and cited art, no claim-specific obviousness/enablement/102-103 analysis can be generated from claims alone.
What patent litigation affects US 9,339,499?
Answer: Litigation status cannot be determined from the claims text provided. Litigation requires docket-level identification, parties, and case numbers tied to US 9,339,499.
Key Takeaways
- US 9,339,499 is a method-of-treatment patent anchored to hydrocodone bitartrate ER dosing in mild or moderate hepatic impairment, with infringement gated by quantitative PK exposure limits (AUC0-inf and, in dependent claims, Cmax).
- Dependent claims add enforceable narrowers: dose strength, IR/ER composition proportions and bead architecture, Cmax percent increase limits, absolute AUC/Cmax windows per 20 mg, and a USP dissolution release profile at pH 6.8.
- The most consequential design-around axes are:
- shifting hepatic impairment AUC0-inf and/or Cmax outside the claimed caps, and/or
- ensuring dosing in hepatic impairment involves dose adjustment rather than the “starting dose not adjusted” method required by Claims 17 and 19, and/or
- modifying dissolution curves to fall outside Claim 16’s release windows.
FAQs
1) Does Claim 1 require an immediate-release component?
No. Claim 1 requires an extended-release formulation, with immediate-release present only in dependent Claims 4–6.
2) Which PK metric is strictly required by Claim 1?
AUC0-inf exposure limits for mild (≤14%) and moderate (≤30%) hepatic impairment relative to non-impairment.
3) What is the role of Claim 16’s USP dissolution test in infringement?
It adds an in vitro release-profile constraint in pH 6.8 that can differentiate products even if in vivo PK is similar.
4) Can a product avoid “starting dose not adjusted” infringement?
Potentially, by changing the claimed method fact pattern so that hepatic impairment dosing includes dose adjustment rather than a starting dose unchanged from non-impairment comparators (Claims 17 and 19).
5) Is this patent about formulation manufacturing methods or clinical dosing?
It is primarily about clinical treatment methods defined through PK outcomes and patient characteristics, with formulation mechanics appearing mainly in dependent claims.
References
No references can be provided because no bibliographic identifiers (assignee, filing date, priority, family members, FDA product/NDA, Orange Book listing, prosecution citations, or litigation dockets) were included in the prompt.
