Scope and Claims Analysis for US Patent 12,599,602 Covering Maralixibat Liquid Formulations for Treating Alagille Syndrome (ALGS)
US 12,599,602 is a method-of-treatment claim set focused on administering maralixibat in a specific daily dosing range using a liquid oral pharmaceutical composition that includes sweetener, flavoring agent, and liquid carrier. The independent claim is drafted to be broad on the identity of the sweetener and flavoring agent (by reciting lists), while still locking in the key commercial form factor (liquid) and dosing parameters (400 to 800 μg/kg/day). Dependent claims narrow to sucralose as the sweetener, grape flavor as the flavoring agent, and specific carrier compositions (water + propylene glycol).
For a freedom-to-operate or design-around, the practical claim “hinges” are: (1) maralixibat dosing per kg per day, (2) liquid composition with a required set of excipient categories (sweetener and flavoring agent), and (3) oral administration with optional timing relative to food and treatment duration. If a competing product uses the same active and achieves the same therapeutic effect via a different dosage form (eg, capsule/tablet without sweetener/flavor categories) or a different dosing regimen outside the claimed μg/kg/day window, claim coverage changes materially.
What is the scope of US Patent 12,599,602 and what does claim 1 actually cover?
Featured-snippet answer: Claim 1 covers a method for treating ALGS by administering a liquid pharmaceutical composition containing maralixibat at 400 to 800 μg/kg/day, where the liquid composition contains a sweetener, a flavoring agent, and a liquid carrier.
Independent claim 1 elements (all required)
Claim 1 is structurally a closed “composition-for-use” method, where all recited components must be present in the administered composition and the method must match the recited dosing.
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Therapeutic target
- “Treating Alagille Syndrome (ALGS)”
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Route and form
- Administering a “liquid pharmaceutical composition”
- Dependent claims confirm oral use and timing (claims 19-20), but claim 1 already ties the method to a liquid dosage form.
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Active and dose range
- maralixibat amount: about 400 μg/kg/day to about 800 μg/kg/day
- This is the central quantitative limitation.
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Composition excipient categories (required)
- A sweetener
- A flavoring agent
- A liquid carrier
How “about” expands risk
The “about” qualifiers around the 400–800 μg/kg/day range typically broaden coverage beyond exact endpoints. In practical design-around, a product that shifts outside the range must account for prosecution history and infringement constructions on “about.” The claim does not define the permissible tolerance.
What claim 1 does not require
Based solely on the provided claims:
- It does not require any particular buffer, pH, viscosity, polymer, or preservative (other than the category requirements).
- It does not require any particular concentration, volume, or formulation viscosity.
- It does not require any specific treatment duration (those are in dependent claims).
- It does not require any specific patient demographic beyond ALGS (though dependent claims include pediatrics and age).
What specific dose and formulation constraints narrow protection in dependent claims?
Dose narrowing: claim 9
Claim 9 limits maralixibat to: 360 to 440 μg/kg/day.
That creates a second “dose corridor” within claim 1’s broader range. If an accused product sits in:
- 360–440 μg/kg/day, it can land directly on claim 9 and still on claim 1.
- 440–800 μg/kg/day, it can still infringe claim 1 but not claim 9 (unless “about” makes overlap arguable).
- below ~400 or above ~800 μg/kg/day, it avoids claim 1’s core dose range, subject to how “about” is interpreted.
Dosing frequency narrowing: claims 10–11
- Claim 10: once daily (QD)
- Claim 11: twice daily (BID)
These are alternative dependent claim paths. A product could be engineered to use the same liquid formulation categories but a dosing cadence not matching either claim language, though if the label uses a different schedule, claim coverage may shift.
Duration narrowing: claims 12–14
- At least 18 weeks (claim 12)
- At least 2 years (claim 13)
- At least 3 years (claim 14)
These depend on the treated method duration. For litigation, the relevant inquiry becomes what regimen is actually administered and claimed; a short-course regimen may not meet duration thresholds.
Which sweeteners and flavoring agents are explicitly claimed, and how broad is the coverage?
Sweetener scope: claim 2
Claim 2 limits claim 1 by selecting sweeteners from a defined list including:
- Aspartame
- Saccharin and salts (sodium/potassium/calcium saccharin)
- Acesulfame potassium
- Sucralose
- Alitame
- Xylitol
- Cyclamate
- Neohesperidine dihydrochalcone
- Natural/plant intense sweeteners: thaumatin, stevioside, rebaudioside
Breadth implication: If the accused product uses any listed sweetener, the sweetener element is met. If it uses non-listed sweeteners (eg, certain polyols or blends not falling into the enumerated categories), claim 2 may be avoided, but claim 1 still requires “a sweetener” generically and does not restrict identity. That means claim 1 could still be infringed even if claim 2 is avoided.
Sucralose-specific claim: claim 3
- Claim 3 narrows claim 2 to sucralose.
Practical takeaway: Sucralose-containing formulations face the tightest path: they can match claim 2 and claim 3 if dosing and other elements are met.
Flavoring scope: claim 4
Claim 4 lists extensive flavoring agents, including:
- Acacia syrup
- Acesulfame K (notably, acesulfame K is listed both as a sweetener and a flavoring agent in different parts of the claims)
- Fruit flavors like apple, banana, berry, grape, grapefruit, honey, lemon, lime, cherry, and many variants
- Other listed components: caramel, cocoa, cola, cotton candy, licorice syrup
- “Glycyrrhiza (licorice) syrup” specifically recited
Breadth implication: The list is long and covers many common oral pediatric flavor strategies. Avoiding infringement by flavor selection alone is difficult if the desired flavor is among the enumerated options.
Grape flavor-specific claim: claim 5
- Claim 5 narrows claim 4 to grape flavor.
A grape-flavored liquid maralixibat product is positioned to meet claim 4 and claim 5 if other limitations align.
What carrier limitations exist and why do they matter for design-around?
Water carrier: claim 6
- “Liquid carrier comprises purified water.”
Propylene glycol: claim 7
- “Liquid carrier comprises propylene glycol.”
Carrier consists of water + propylene glycol: claim 8
- “Liquid carrier consists of the combination of purified water and propylene glycol.”
Scope implication:
- Claim 1 requires a “liquid carrier” but does not require any particular carrier composition.
- Claims 6–8 increase carrier specificity and can be triggered depending on the actual excipient system.
Design-around logic (formulation strategy):
- Using water-only or water+propylene glycol could risk claims 6 or 7.
- Using water+propylene glycol plus additional carriers/polymers could avoid claim 8 (“consists of”) while still satisfying claim 6 and/or 7 unless extra carrier components change whether propylene glycol is present and whether “comprises” still applies (claims 6–7 use “comprises,” which is broader than “consists”).
What patient and administration constraints add further layers of infringement risk?
Patient group and baseline condition: claims 15–17
- Claim 15: “subject exhibits below normal height or weight prior to administration”
- Claim 16: “subject experiences pruritus prior to administration”
- Claim 17: “subject is a pediatric subject”
These are method features tying the patient phenotype to the ALGS treatment. For infringement, the accused therapy would need to involve those patient conditions.
Age threshold: claim 18
- “subject is at least 1 year of age.”
Timing relative to food: claim 19
- “administered prior to ingestion of food.”
Route: claim 20
Even though claim 1 says “liquid pharmaceutical composition,” claim 20 explicitly locks in oral administration. If an accused regimen uses a non-oral administration route (or bypasses oral intake in a way that is not “administered orally”), claim 20 may not be met, though claim 1 still may be met depending on how “liquid composition” is treated in claim construction and how the method is practiced.
How strong is the patent estate around this exact active and formulation concept?
What US 12,599,602 is likely protecting (based on claim scope)
This patent’s claims are anchored on:
- Maralixibat as the active
- ALGS as the indication
- Liquid oral composition with sweetener + flavoring agent + liquid carrier
- A defined mg/μg/kg/day range and sub-range
- Pediatric use and pruritus/low growth phenotype (dependent claims)
- Specific excipients (sucralose and grape flavor; water + propylene glycol)
Estate strength interpretation:
- Breadth is strongest at claim 1 (dose range + required excipient categories).
- Breadth narrows at the dependent claim layers but those layers align with common pediatric liquid formulation choices (sweeteners, flavors, and carriers).
Without the rest of the family record (continuations, divisionals, priority filings) and without a USPTO/public litigation docket, a complete landscape across all related patents cannot be reproduced from the provided claim text alone.
What generic entry risks exist for maralixibat ALGS liquid products under this patent?
Highest-risk scenario
A competitor launching a generic or “authorized” version that:
- uses a liquid oral formulation,
- includes a sweetener and flavoring agent (as claimed categories),
- uses maralixibat at 400–800 μg/kg/day (with “about” tolerance),
- and treats patients in the ALGS setting consistent with the claimed duration and phenotype (depending on whether dependent claims are asserted)
This creates both:
- literal infringement exposure (claims 1, and potentially 2–8 and 9–20 depending on specifics), and
- increased settlement pressure because the claim is directly tied to “how the drug is given” in common pediatric use.
Design-around levers (where the claim language leaves room)
Based on the provided claims, the following levers would reduce infringement likelihood:
- Dose regimen outside about 400–800 μg/kg/day
- Avoiding “sweetener”/“flavoring agent” presence is unlikely commercially for palatability in pediatrics, but if a competitor formulates without the claimed categories, claim 1 would not be met.
- Using a non-liquid dosage form (if practiced as not “liquid pharmaceutical composition”) would be a structural avoidance path, though the claims as provided do not define what counts as “liquid pharmaceutical composition.”
- Avoiding sucralose and grape flavor avoids specific dependent claims (2–5), but does not automatically avoid claim 1 unless the sweetener/flavor elements are also absent or outside the claim categories.
When does this patent lose exclusivity? How do expiration and exclusivity work here?
Answer: Determining the expiration/exclusivity timeline for US 12,599,602 requires its priority date, filing date, and any patent term adjustments or extensions, none of which are provided in the prompt.
What patent litigation affects US 12,599,602, and where do Paragraph IV or biosimilar risks fit?
Answer: A litigation landscape, including any Paragraph IV challenge to a reference listed drug, requires Orange Book context, ANDA/BLA reference drug identifiers, and case dockets. These are not provided, so no complete, accurate litigation mapping can be produced from the supplied information.
US 12,599,602 claim chart-style breakdown (elements mapped to limitations)
| Claim element bucket |
Claim 1 |
Key dependent narrowing |
| Indication |
Treat ALGS |
claims 15–16 add phenotype |
| Dosage form |
Liquid pharmaceutical composition |
claim 20 confirms oral route |
| Active |
Maralixibat |
claim 9 narrows dose to 360–440 μg/kg/day |
| Dose range |
~400–800 μg/kg/day |
claim 9 sub-range |
| Frequency |
Not fixed |
claim 10 QD, claim 11 BID |
| Treatment duration |
Not fixed |
claim 12 18 weeks+, claim 13 2 years+, claim 14 3 years+ |
| Excipient categories (required) |
Sweetener + flavoring agent + liquid carrier |
specific lists in claims 2 and 4; carriers in claims 6–8 |
| Specific sweetener |
Any sweetener |
claim 2 enumerated list; claim 3 sucralose |
| Specific flavor |
Any flavoring agent |
claim 4 enumerated list; claim 5 grape |
| Carrier composition |
Any liquid carrier |
claim 6 purified water; claim 7 propylene glycol; claim 8 water + propylene glycol only |
| Patient attributes |
Not required in claim 1 |
claim 17 pediatric; claim 18 ≥1 year; claims 15–16 growth/pruritus |
| Timing relative to food |
Not fixed in claim 1 |
claim 19 prior to ingestion of food |
How does US 12,599,602 compare with typical maralixibat patent patterns for ALGS?
Answer: A comparative analysis across the full maralixibat ALGS US patent family (formulations, dosing regimens, methods of use, manufacturing methods) requires other listed patents and claim sets. Those are not included, so a family-wide comparison cannot be made accurately from the provided text.
Key Takeaways
- US 12,599,602’s independent claim 1 is a broad method claim for ALGS that requires a liquid oral composition containing maralixibat at about 400–800 μg/kg/day, with sweetener, flavoring agent, and liquid carrier.
- The practical infringement risk concentrates on the dose window and on whether the administered liquid includes the claimed excipient categories.
- Dependent claims add high-value specificity aligned with common pediatric formulations:
- Sucralose (claim 3) and grape flavor (claim 5)
- Purified water and propylene glycol carrier options (claims 6–8)
- 360–440 μg/kg/day sub-range (claim 9)
- Administration patterns (QD/BID), duration thresholds, and pediatric/phenotype features (claims 15–18)
- Design-around is most plausibly achieved by moving the maralixibat regimen outside the claimed μg/kg/day ranges, altering the dosage form away from a “liquid pharmaceutical composition,” or changing the excipient system so that required categories are not met.
FAQs
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Do claims 2 and 3 (sucralose) control infringement if the product uses a different sweetener?
Claim 2 restricts only that dependent path, but claim 1 still requires a sweetener category without specifying identity.
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If a product uses a grape flavor but a different dosing schedule, does it still risk claim 1?
Claim 1 does not require QD or BID; it focuses on the liquid composition, ALGS indication, and the ~400–800 μg/kg/day dose range.
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How do claims 6–8 affect a formulation with water plus propylene glycol plus additional excipients?
Claims 6 and 7 use “comprises,” so they may still be met if water and propylene glycol are present. Claim 8’s “consists of” is narrower.
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Does meeting the ALGS indication alone guarantee infringement of dependent claims 12–14?
No. Dependent claims require specific treatment duration thresholds (18 weeks, 2 years, 3 years).
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What is the highest leverage change for a potential competitor: excipient swaps or dose changes?
Based on claim structure, dose is the primary quantitative lever, while excipient swaps may avoid specific dependent claims but not necessarily claim 1.
References (APA)
- United States Patent 12,599,602.
