Scope and claims analysis for U.S. Patent 9,629,841 (Compound A + copovidone hepatitis C composition)
U.S. Patent 9,629,841 is a composition-and-method patent that narrows protection to oral hepatitis C pharmaceutical compositions containing a specific active (N-(6-(3-tert-butyl-5-(2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)-2-methoxyphenyl)naphthalen-2-yl)methanesulfonamide, “Compound A” with defined solubility) plus a defined bioavailability enhancer (copovidone) at defined weight ranges, paired with constrained solid-form and performance metrics (biphasic dissolution solubility and exposure targets). Claim breadth is mostly driven by the quantitative copovidone range and the biphasic dissolution threshold, with additional “fence lines” around dose strength (about 200-300 mg), ratio, tableting/tensile strength improvements, and optional salt/crystal specificity (including a “pattern B” monosodium monohydrate).
What does U.S. Patent 9,629,841 claim: Compound A + copovidone hepatitis C oral tablets?
Core protected subject matter (Claim 1): an oral pharmaceutical composition comprising
- Active: Compound A (or pharmaceutically acceptable salt) at ~200 mg to ~300 mg (free acid equivalent basis), and
- Bioavailability enhancer: copovidone at ~10% to ~25% by weight, and
- Performance requirement: Compound A has biphasic dissolution solubility ≥ 20 mcg/mL at 100 minutes (measured by the patent’s biphasic dissolution test).
Claim structure: Claim 1 is the anchor for all downstream composition and method claims. Claims 23-24 cover hepatitis C treatment via administering a Claim 1 composition. Claims 25-27 cover manufacturing and tabletability improvements. Claims 26 and 27 create additional hooks around use and process effects.
Key claim elements that define scope
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The identity of Compound A
- The active is specified by full IUPAC-like name (and extends to salts). That specificity limits workarounds based on active substitution.
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Copovidone as the required bioavailability enhancer
- Protection is tied to copovidone, not a broader “polymer” class. Replacing copovidone with a different solubilizer/dispersant can be a primary design-around.
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Weight % and dose mg boundaries
- Copovidone range: 10% to 25% by weight.
- Compound A range: 200 mg to 300 mg per free-acid-equivalent basis.
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A functional solubility requirement with a defined test window
- “Biphasic dissolution test” with ≥ 20 mcg/mL at 100 minutes is a performance limitation. This matters for infringement because it can force comparison to the patent-defined dissolution method and the test outcome.
How broad are Claim 1 and dependent claims 2-22: what copovidone ranges and dose strengths are covered?
Claim 1 already includes ranges for dose and copovidone content. The dependent claims tighten them into narrower “islands” that can still be infringed if a commercial product lands inside those islands.
Dose strength fences (Claim 7-8 and 17-20)
- Claim 7: ~250 mg Compound A (free acid equivalent).
- Claim 8: Compound A ≥ 20% by weight.
- Claims 17-20: oral dosage form weight <1500 mg, Compound A at specific bands:
- Claims 17: 225-275 mg
- Claims 18-20: 240-260 mg (multiple nested claims) and 245-255 mg (tightest band)
These dependent claims matter for products formulated at particular milligram strengths.
Copovidone level fences (Claim 10 and 31)
- Claim 10: copovidone 10% to 20% by weight.
- Claim 31: copovidone about 15% by weight.
If a product uses ~15% copovidone, it squarely falls into Claim 31 and, by extension, still sits within Claim 1 if it stays within 10-25%.
Ratio fences (Claim 2, 21-22, 28)
- Claim 2: bioavailability enhancer:Compound A 4:1 to 1:8 (free-acid-equivalent basis).
- Claims 21-22: oral dosage form with Compound A ~240-260 mg and ratio 1:1 to 1:4.
- Claim 28: ratio 1:1 to 1:3.5.
These ratio claims are likely the easiest way to separate formulations. A competitor can attempt to shift the weight relationship while staying within copovidone and dose ranges.
What salt and crystalline form limitations exist: does the patent cover specific “pattern B” sodium monohydrate?
Yes. While Claim 1 covers Compound A or salts generically, dependent claims narrow to a specific salt form:
- Claim 3: composition includes a salt of Compound A.
- Claim 4: salt is a sodium salt.
- Claim 5: sodium salt is pattern B crystalline monosodium salt.
- Claim 6: pattern B monosodium salt is a monohydrate.
Practical scope implication:
- If an accused product uses a sodium salt but not the specified “pattern B” crystalline monosodium monohydrate, it may avoid Claims 5-6 while still potentially falling within Claim 1’s broader “salt thereof” language.
- But if the accused product uses the pattern B monosodium monohydrate, it inherits the tighter dependent coverage.
What performance metrics are required: how do the biphasic dissolution solubility thresholds constrain infringement?
Claim 1 requires:
- biphasic dissolution solubility ≥ 20 mcg/mL at 100 minutes
Dependent performance claims add additional thresholds and test conditions:
- Claim 30: solubility ≥ 30 mcg/mL at 100 minutes.
- Claim 32: test parameters:
- Temperature: 37±0.2°C
- Aqueous phase: 40 mL of 80 mM phosphate buffer
- Organic phase: 30 mL octanol
Scope effect:
- Claim 1 can be infringed even if the product does not hit 30 mcg/mL, as long as it meets ≥20 mcg/mL using the patent’s biphasic dissolution framework.
- Claim 30 gives additional coverage for high-performing formulations.
- Claim 32 creates a detailed method anchor that can become central to testing disputes.
What pharmacokinetic exposure targets are claimed: AUC24 and Cmax limits in tablet dosing?
Two dependent claims add explicit human PK targets:
- Claim 15: single-dose AUC24 ≥ 4500 ng·hr/mL (population average).
- Claim 16: single-dose AUC24 ≥ 5000 ng·hr/mL and average Cmax < 1200 ng/mL.
How these affect scope:
- These are use-performance claim elements tied to “the tablet when administered.”
- They are narrower than Claim 1’s in vitro solubility requirement and can be used as additional infringement “confirmers” for products with matching PK outcomes, especially in litigation where dissolution performance can be debated but human exposure data exists.
What other formulation limitations are present: intragranular copovidone and tablet properties?
Intragranular polymer location (Claim 29)
- Claim 29: copovidone is present as an intragranular component.
This can matter where copovidone is only used as a binder, dispersion aid, or surface coating rather than in the granules.
Tabletability improvement (Claim 27)
- Claim 27: method improving tabletability by tableting a Claim 1 composition where the tablet has improved tensile strength compared to a similarly tableted composition not containing copovidone.
This is a process-by-effect claim. It can catch formulations that use copovidone even if their dissolution/PK characteristics are otherwise hard to litigate, provided tensile strength comparisons line up.
What is covered for manufacturing: does Claim 25 require simple blending?
- Claim 25: method for preparing the composition comprising blending Compound A (or salt) and copovidone.
This is not a complex manufacturing claim. It creates a straightforward hook that can be asserted against generic manufacturing steps if the end composition still meets Claim 1.
Does the patent claim treatment of hepatitis C and methods of enhancing bioavailability?
Yes.
- Claim 23: method for treating hepatitis C by administering a Claim 1 composition.
- Claim 24: optionally adds one or more additional therapeutic agents.
- Claim 26: method of enhancing bioavailability by preparing a Claim 1 composition and administering it.
Scope nuance:
- Claim 24 allows combination therapy, which can reduce the ability to argue “monotherapy only.”
- Claim 26 parallels the composition’s PK intent and can be asserted even where hepatitis C treatment is framed under bioavailability improvement rationale.
How does the claim set structure map to design-around strategies?
From a competitor standpoint, the claim set establishes multiple independent “gates”:
- Active identity gate: swapping the active away from Compound A likely avoids most of the estate.
- Polymer gate: using a different polymer than copovidone can avoid Claim 1’s composition requirement.
- Quantitative gates: even with copovidone, staying outside:
- 10-25% by weight copovidone
- 200-300 mg free-acid-equivalent dose
- ratio windows (4:1 to 1:8; or 1:1 to 1:4; or 1:1 to 1:3.5)
can reduce risk depending on which dependent claims are asserted.
- Performance/test gate: failing the ≥20 mcg/mL biphasic dissolution threshold (using the patent method) can avoid Claim 1.
- Form/salt gate: avoiding “pattern B” sodium monohydrate can avoid Claims 5-6, but not necessarily Claim 1 if a different salt form is still used and meets the dissolution threshold.
- Dose-form gate: tablet limitation appears in Claims 11-14. If a competitor uses capsules, Claim 1 still covers “pharmaceutical composition” generally, but infringement strategies often try to avoid specific oral tablet dependent claims.
- PK gate: AUC24/Cmax targets (Claims 15-16) can be harder to meet if formulation changes affect exposure.
What is the probable commercial product profile implied by the claim set?
The dependent claims describe an oral tablet with:
- total tablet weight < 1500 mg
- Compound A strength centered around 240-260 mg (with additional tight bands at 245-255 mg)
- copovidone around 10-20% and potentially ~15%
- dissolution performance tuned to a biphasic threshold at 100 minutes
- human PK suggesting high systemic exposure (AUC24 thresholds) while keeping Cmax under 1200 ng/mL
This combination suggests a formulation engineered for solubility-limited absorption and controlled peak exposure.
Which jurisdictions and regulatory contexts matter: how does Orange Book style exclusivity align with this composition patent?
The claims are U.S. composition and method claims. Operationally, infringement risk usually ties to:
- FDA approval pathway for the specific NDA/ANDA product carrying this active/salt strength
- Orange Book listings for the specific formulation and method-of-use patents
- potential Paragraph IV challenges if a generic seeks approval before patent expiry
However, no Orange Book or publication metadata is provided in the prompt. Without the patent’s application number, listed drug product name, NDA/ANDA association, or Orange Book entry details, the exact “status and expiry dates” and who is likely challenging are not determinable from the provided claim text alone.
Accordingly, the analysis below focuses on legal scope mechanics rather than timeline commitments.
How many distinct claim “themes” exist inside U.S. Patent 9,629,841?
The claim set can be grouped into five enforceable themes:
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Composition theme (Claim 1)
Compound A + copovidone + dissolution performance + dose range.
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Composition refinement theme (Claims 2, 7-22, 28-31)
Ratios, salt form (Claims 3-6), and specific dose/copolymer levels; plus intragranular placement.
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Human performance theme (Claims 15-16)
AUC24 and Cmax constraints for a tablet.
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Manufacturing and property theme (Claims 25 and 27)
blending method and improved tensile strength with copovidone.
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Therapeutic and exposure methods theme (Claims 23, 24, 26)
hepatitis C treatment and bioavailability enhancement through administration of Claim 1 composition.
How does this patent likely compare with other formulation patents for solubility-limited actives?
Relative to typical solubility-improvement patents, the estate is more tightly drafted because it:
- fixes the polymer type to copovidone rather than a broad excipient class
- includes a quantified in vitro dissolution endpoint (biphasic dissolution at 100 minutes)
- overlays human PK targets and tabletability improvements
This structure tends to increase the chance of both (a) enforcement leverage when a product is close and (b) defendability by providing multiple objective metrics (dissolution and PK).
Key takeaways
- U.S. Patent 9,629,841 protects a specific oral hepatitis C composition defined by Compound A (or salts) plus copovidone at 10-25 wt%, with Compound A at 200-300 mg and biphasic dissolution solubility ≥ 20 mcg/mL at 100 minutes.
- Dependent claims tighten risk windows around:
- copovidone content (10-20 wt%, ~15 wt%)
- mg strengths centered on 240-260 mg and tight bands 245-255 mg
- polymer:active weight ratios (4:1 to 1:8; and 1:1 to 1:4 / 1:1 to 1:3.5)
- Salt/crystal scope includes “pattern B” sodium monohydrate via Claims 3-6.
- Performance coverage is multilayered: dissolution thresholds (≥20 and ≥30 mcg/mL) plus human PK targets (AUC24 and Cmax).
- Method coverage extends to hepatitis C treatment (administering the composition), bioavailability enhancement, blending for preparation, and tablet tensile-strength improvement due to copovidone.
FAQs
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Does U.S. Patent 9,629,841 cover formulations that use copovidone outside 10–25 wt%?
Claim 1’s copovidone weight fraction is limiting; formulations outside 10–25 wt% avoid Claim 1 unless other independent claims apply.
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If a product uses a different salt form of Compound A, can it still infringe?
Yes, because Claim 1 covers “Compound A, or a pharmaceutically acceptable salt thereof.” The “pattern B monosodium monohydrate” limits only apply to Claims 3-6.
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Is infringement dependent on achieving the biphasic dissolution solubility threshold?
Yes. Claim 1 includes a quantified dissolution requirement that must be satisfied under the biphasic dissolution test as claimed.
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Can combination therapy avoid the patent?
Not on the basis of combination alone, because Claim 24 permits additional therapeutic agents alongside administration of the claimed composition.
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What is the likely biggest design-around lever for competitors?
Replacing copovidone with a different bioavailability enhancer and/or adjusting the formulation to miss the dissolution threshold and/or the quantitative copovidone/dose ratio constraints.
References
- United States Patent 9,629,841. “Pharmaceutical composition comprising a compound and copovidone.” (Claim text provided in prompt).
