United States Patent 4,859,660: Scope, Claims, and US Patent Landscape for Ursodeoxycholic Acid in Primary Biliary Cirrhosis
What does US 4,859,660 actually claim?
US Patent 4,859,660 claims methods for treating primary biliary cirrhosis (PBC) by administering ursodeoxycholic acid (UDCA) to a patient with PBC.
The independent claim (Claim 1) is a medical method claim with a single operative limitation: administering an effective amount of UDCA.
Claim set (as provided)
| Claim |
Claim type |
Core limitation(s) |
Practical breadth |
| 1 |
Method |
Treat PBC by administering “an effective amount” of UDCA |
Broadest; covers any dosing form/route that meets “effective amount” |
| 2 |
Dependent |
13 to 15 mg/kg/day UDCA |
Narrows to a specific daily dose range |
| 3 |
Dependent |
UDCA administered orally |
Narrows by route (oral) |
| 4 |
Dependent |
UDCA administered in gelatin capsules |
Narrows by dosage form (gelatin capsules) |
How broad is “effective amount” in Claim 1?
Claim 1 uses a functional threshold: “an effective amount.” For scope, that phrase typically captures dosing regimens that clinicians would consider therapeutically effective for PBC, without tying the invention to a fixed mg/kg/day figure.
Scope implications
- No fixed dose is required for infringement under Claim 1, as long as the administered amount is “effective.”
- No route/dosage form is required for Claim 1. Any route that constitutes treatment by UDCA administration can fall within scope.
- Dependent claims (2-4) introduce narrower, more specific regimes that can be used for enforcement where dose, route, or dosage form are known.
What is the enforceable “center of gravity” of the patent?
In most landscapes like this, the strongest enforcement anchor is the specific regimen captured by dependent claims, because they are less vulnerable to “not effective amount” arguments and more tied to commercially used dosing.
Claim hierarchy and practical narrowing
- Claim 1: any effective UDCA administration for PBC
- Claim 2: 13 to 15 mg/kg/day
- Claim 3: oral administration
- Claim 4: oral gelatin capsules
A commercial regimen that matches 13 to 15 mg/kg/day given orally in standard capsule form maps closely to the full dependent stack (Claims 2-4). A regimen outside 13-15 mg/kg/day could still fall under Claim 1 if it is “effective.”
Is the patent limited to a particular patient population?
From the claim language provided, the only patient condition is “a patient suffering from primary biliary cirrhosis.” There is no express limitation to:
- disease stage,
- prior therapy,
- baseline biochemical thresholds,
- co-medication,
- age or sex.
That means the method scope attaches to the diagnosis label rather than treatment history. Any patient meeting the PBC diagnosis and receiving UDCA as claimed is within the claim’s target.
Where are the claim limitations strongest for litigation?
1) “Primary biliary cirrhosis” as the trigger
Infringement requires the treated condition to be PBC. In practice, proving “PBC” can turn on:
- medical documentation of diagnosis, and
- clinical criteria used at the time of treatment.
The claim text itself does not specify diagnostic criteria, so evidentiary proof typically drives this limitation.
2) “Ursodeoxycholic acid” as the active agent
The method requires UDCA itself. It does not cover:
- epimers or analogs unless they are UDCA,
- conjugates unless the administration is UDCA,
- mixtures unless UDCA is the administered active.
3) Dose and route constraints in dependent claims
Claims 2-4 reduce ambiguity:
- Claim 2 sets 13 to 15 mg/kg/day
- Claim 3 requires oral dosing
- Claim 4 requires gelatin capsules
If a competitor uses a different dose band, a different oral formulation (e.g., tablets, softgels, solution), or a different route (e.g., enteral feeding tube), it may avoid the dependent claims while still potentially facing Claim 1 arguments if the regimen qualifies as an “effective amount.”
Claim construction risk points
Based on the language provided, the main construction uncertainties are typical for functional and medium-limited method claims:
- “Effective amount”: whether courts treat it as a factual question (clinical effectiveness) or a determinable range.
- “Orally”: typically straightforward, but could become disputed if administration is via alternative enteral routes.
- “Gelatin capsules”: narrower and more literal. Softgel dosage forms or non-gelatin shells can be outside Claim 4 even if UDCA is orally administered.
How does this map to standard UDCA practice?
Claim 2’s regimen (13 to 15 mg/kg/day) is a band rather than a single number. That band is consistent with typical PBC dosing strategies used historically for UDCA in clinical practice, which increases the chance that real-world prescribing fits the dependent claims.
Claim 1 coverage vs. dependent claims: infringement exposure matrix
The following matrix shows how a hypothetical prescribing pattern aligns with the provided claims. (Alignment is based only on the claim text you supplied.)
| Treatment pattern |
Claim 1 (effective UDCA for PBC) |
Claim 2 (13-15 mg/kg/day) |
Claim 3 (oral) |
Claim 4 (gelatin capsules) |
| UDCA at an effective dose, any route/form |
Potential |
Not required |
Not required |
Not required |
| UDCA effective dose but <13 or >15 mg/kg/day |
Potential |
No |
Depends |
Depends |
| UDCA effective dose within 13-15 mg/kg/day, oral |
Potential |
Yes |
Yes |
Depends |
| Same dosing as above, oral but not gelatin capsules (e.g., tablets) |
Potential |
Yes |
Yes |
No |
| UDCA not oral route (e.g., non-oral) but effective |
Potential |
Depends |
No |
No |
This is the practical enforcement geometry: companies are most exposed when their commercially used PBC dosing matches the band and form.
What is the patent landscape around UDCA for PBC in the US?
A complete landscape requires a full claims-and-filings review across USPTO and related family members. With only the claim text and the patent number, the only defensible landscape elements are the generic claim footprint and likely US filing strategy implied by this patent.
That said, the landscape around UDCA in PBC typically consists of:
- method-of-treatment patents tied to the diagnosis (PBC),
- dose-range patents (mg/kg/day windows),
- route/formulation dependent claims (oral; capsules),
- and eventually composition and labeling around UDCA products.
Landscape segmentation by claim type
| Category |
Typical US claim structure |
How 4,859,660 sits |
| Core method |
“Administer UDCA to patient with PBC” |
Claim 1 |
| Dose-range method |
Fixed mg/kg/day band |
Claim 2 |
| Route-specific method |
Oral vs non-oral |
Claim 3 |
| Dosage form method |
Capsules (gelatin) |
Claim 4 |
Design-around levers visible in the claim set
- Avoid Claim 4: use a different oral dosage form (non-gelatin capsule, tablet, softgel), keeping UDCA oral and effective.
- Avoid Claim 3: use a non-oral route (if clinically acceptable).
- Avoid Claim 2: dose outside 13 to 15 mg/kg/day.
- Still consider Claim 1 exposure: any effective UDCA administration for PBC can still risk Claim 1 infringement.
What does this mean for R&D or freedom-to-operate strategy?
If your program is UDCA-based for PBC
- Regimen matching is high-risk: an oral UDCA regimen within 13 to 15 mg/kg/day in gelatin capsules is a tight map to Claims 2-4.
- Regimen shifting is not risk elimination: altering dose and/or dosage form may reduce dependent-claim coverage but can still trigger Claim 1 if UDCA is clinically effective for PBC.
If your program is a UDCA alternative (different bile acid)
This patent’s literal scope is limited to ursodeoxycholic acid. A non-UDCA bile acid would typically sit outside on the active-ingredient limitation, unless it is UDCA in disguise or is treated as equivalent by claim interpretation (which is not supported by the claim language you provided).
What are the key business implications of each claim layer?
Claim 1 (broad method coverage)
- Enforcement path: easiest to allege because it covers broad dosing and administration modes, as long as the amount is “effective.”
- Defenses: attack “effective amount” and “PBC diagnosis” evidence; argue administration was not UDCA or not for PBC.
Claim 2 (dose band)
- Enforcement path: strong when a competitor’s label dosing matches 13-15 mg/kg/day.
- Defenses: dosing records; argue actual administered dose did not fall in the band.
Claim 3 (oral)
- Enforcement path: helps narrow when non-oral delivery exists.
- Defenses: route proof (oral vs enteral/non-oral).
Claim 4 (gelatin capsules)
- Enforcement path: highest specificity; useful where products use gelatin capsules.
- Defenses: shell material and dosage form (gelatin vs non-gelatin; softgel vs hard gelatin capsules).
Key Takeaways
- US 4,859,660 is a method-of-treatment patent for PBC using ursodeoxycholic acid (UDCA).
- Claim 1 is the broad foundation: it covers administration of an “effective amount” of UDCA for a PBC patient, without specifying dose, route, or dosage form.
- Claims 2-4 narrow the scope to 13 to 15 mg/kg/day, oral administration, and gelatin capsules.
- Design-around strategy based on this claim set: changing dose band, route, or gelatin capsule form can reduce coverage under dependent claims, but Claim 1 exposure remains for effective UDCA administration for PBC.
FAQs
1) Does Claim 1 require a specific UDCA dose?
No. Claim 1 requires only administration of an effective amount of UDCA for PBC.
2) Can oral UDCA at 10 mg/kg/day infringe?
It can still potentially infringe Claim 1 if 10 mg/kg/day is “effective,” but it would not meet Claim 2’s 13 to 15 mg/kg/day limitation.
3) Does Claim 4 cover softgels?
Claim 4 specifies gelatin capsules. Softgels depend on whether they qualify as gelatin capsules under the claim term; the claim language is form-specific.
4) Is the patent limited to treatment-naive patients?
The provided claim text does not state any limitation to prior-treatment status.
5) Is the patent limited to a particular PBC stage?
The provided claim text does not specify disease stage or severity thresholds.
References
[1] United States Patent 4,859,660 (claims provided by user).
