United States Drug Patent 6,143,326: Claims, Scope, Expiration and Ibandronate Patent Landscape

U.S. Patent No. 6,143,326 protects a narrowly defined method of treating bone disease with orally administered ibandronate tablets. The claimed tablet must contain 0.1 to 100 mg of ibandronate in its core and a specific ibandronate-free coating composed of methylhydroxypropylcellulose, titanium dioxide, polyethylene glycol and talc in stated proportions. The patent issued on November 7, 2000, and its term expired in December 2017 based on the recorded priority and filing history. It does not provide current patent protection against generic ibandronate products.

What does U.S. Patent 6,143,326 cover?

The patent covers a treatment method, not ibandronate as a chemical compound and not every ibandronate tablet.

Its independent claim requires all of the following:

Claim limitation	Required scope
Patient	A patient in need of treatment
Disease	A bone disease
Route	Oral administration
Dosage form	A tablet
Tablet core	Contains about 0.1 to 100 mg of ibandronate
Coating	Is free of ibandronate
Coating composition	Approximately 51.425% methylhydroxypropylcellulose, 24.650% titanium dioxide, 15.000% polyethylene glycol and 8.925% talc

The four coating components total 100% by weight. The claim therefore targets a particular film-coating formulation rather than a general coating concept.

Ibandronate may be present as ibandronic acid, a salt, or another pharmaceutically acceptable form depending on the patent specification and construction of the term. The claim text supplied by the requester does not independently resolve the chemical-form issue. The commercial product historically used ibandronate sodium.

How do claims 1, 2 and 3 differ?

Claim 1 is the controlling independent claim. Claims 2 and 3 narrow the disease limitation.

Claim	Additional limitation	Commercial significance
1	Treatment of a bone disease using the specified coated ibandronate tablet	Broadest claim, but still limited by the exact coating and dose range
2	Bone disease related to a disorder in calcium metabolism	Covers a narrower disease category
3	Hypercalcemia, osteoporosis, tumor osteolysis or Paget's disease	Identifies four specific indications

Claim 3 does not cover every indication for ibandronate. A product used for an unlisted bone disease could fall outside claim 3 while remaining potentially relevant to claim 1 if the broader “bone disease” language is satisfied.

What formulation is protected by U.S. Patent 6,143,326?

The protected formulation has an ibandronate-containing tablet core and an external coating with the following nominal composition:

Coating ingredient	Claimed percentage by weight
Methylhydroxypropylcellulose	51.425%
Titanium dioxide	24.650%
Polyethylene glycol	15.000%
Talc	8.925%
Total	100.000%

The coating must be free of ibandronate. This requirement separates the active ingredient from the coating and may be relevant to stability, taste, handling and controlled exposure of the tablet core.

The claim uses “about” before both the dose range and the coating percentages. That language generally permits some variation, but it does not create an unlimited range. The legally relevant tolerance would depend on claim construction, the specification, prosecution history, technical evidence and, where applicable, the doctrine of equivalents.

The claim does not expressly require:

A specific ibandronate salt;
A particular tablet weight;
A particular dissolution profile;
A particular release rate;
A specific manufacturing process;
A monthly dosing schedule;
A specific package or labeling format; or
A specific patient age or gender.

Those omissions limit the patent’s reach to the stated formulation and method elements.

How strong is the patent estate for ibandronate?

The patent estate historically included separate protection for the active compound, formulations and commercial uses. U.S. Patent 6,143,326 was a formulation and method patent within that broader estate.

Patent category	Representative protection	Relevance
Active ingredient	U.S. Patent No. 5,583,122	Core ibandronate or ibandronic-acid compound protection
Tablet formulation and treatment method	U.S. Patent No. 6,143,326	Specific coated tablet and bone-disease treatment method
Related formulation patents	U.S. Patents including 6,294,196 and other listed patents	Additional formulation or dosage-form coverage
Later commercial protections	Additional Boniva-related patents and regulatory exclusivities	Depended on product, dosage form and listing history

The active-ingredient patent expired before the formulation patent. The 6,143,326 patent extended formulation-related protection beyond the compound patent, but it expired in 2017. The estate therefore had meaningful historical value during the launch and early generic-entry period but has no remaining U.S. term based on this patent.

When did U.S. Patent 6,143,326 expire?

The patent issued November 7, 2000. Public patent records identify a December 23, 1996 priority date and a December 23, 1997 U.S. filing date. Under the modern patent-term framework, the relevant term runs approximately 20 years from the earliest effective nonprovisional filing date, subject to patent-term adjustment, terminal disclaimers and other statutory adjustments. Public Orange Book records identify December 23, 2017 as the expiration date associated with U.S. Patent 6,143,326.[1][2]

Event	Date
Earliest reported priority date	December 23, 1996
U.S. filing date	December 23, 1997
Patent issued	November 7, 2000
Recorded Orange Book expiration	December 23, 2017
Current status	Expired

The expiration date eliminates current infringement risk based solely on the patent. It also means that a new generic applicant no longer needs to overcome this patent through a Paragraph IV certification.

What was the Orange Book status of U.S. Patent 6,143,326?

U.S. Patent 6,143,326 was historically listed in connection with Roche’s Boniva products, including ibandronate sodium tablets. Boniva was approved by the FDA under NDA 021455. The product was approved for osteoporosis treatment, with oral tablet strengths and dosing regimens that included daily and monthly administration.[3]

Orange Book listings identify patents associated with approved drug products, but listing does not establish validity or infringement. A listed method-of-use patent may be addressed through a section viii statement if the applicant omits the patented use from its labeling. A formulation patent can require a Paragraph IV certification if the applicant contends that the patent is invalid, unenforceable or not infringed.

Because 6,143,326 expired in 2017, its prior Orange Book listing has no current blocking effect. The relevant commercial question is historical entry timing, not present-day FDA approval risk.

What Paragraph IV challenges affected ibandronate?

Generic applicants seeking approval for ibandronate tablets could have challenged listed Boniva patents through Paragraph IV certifications under the Hatch-Waxman Act. A Paragraph IV certification states that a listed patent is invalid, unenforceable or will not be infringed by the proposed product.[4]

For this patent, a generic applicant could have pursued several noninfringement positions:

The coating composition falls outside the claimed percentage ranges.
The coating contains ibandronate or does not satisfy the claimed separation between core and coating.
The tablet dose is outside the claimed 0.1 to 100 mg range.
The proposed product is not labeled for a claimed bone disease.
The product does not practice the claimed oral treatment method.
The formulation uses a different coating system or a different dosage form.

Potential validity arguments would have focused on anticipation, obviousness, written description, enablement and indefiniteness, particularly concerning the numerical coating percentages and the meaning of “about.” The narrowness of the formulation limitations would have created substantial noninfringement design-around opportunities.

No current Paragraph IV risk remains for this patent because its term has ended. Historical litigation should be assessed from the individual ANDA cases and settlement documents rather than inferred solely from the Orange Book listing.

Which companies challenged Boniva and ibandronate patents?

The commercial generic market involved ANDA applicants seeking approval for ibandronate sodium tablets after the core compound and formulation exclusivities began to expire. Public FDA records identify multiple generic approvals for ibandronate products over time, including products from manufacturers such as Apotex and other generic applicants.[5]

The principal legal issues in historical litigation would have included:

Whether the ANDA product used the claimed coating composition;
Whether the proposed label induced a claimed method of treatment;
Whether the listed patents were valid and enforceable;
Whether a settlement controlled the first commercial launch date; and
Whether the generic applicant received 180-day first-filer exclusivity.

The existence of an ANDA approval does not by itself establish the outcome of patent litigation. A generic may receive approval after patent expiration, after a settlement, after a court ruling or through a label that omits the patented method.

Does U.S. Patent 6,143,326 cover Boniva's monthly tablet?

The patent could have been relevant to a monthly tablet if that tablet fell within the claimed ibandronate dose and coating composition. Claim 1, however, does not require monthly dosing. It covers the formulation and oral treatment method within the stated dose range.

A 150 mg monthly Boniva tablet would fall outside the literal 0.1 to 100 mg dose range stated in claim 1 if the claim’s dose refers to the amount of ibandronate in the administered tablet. This is a material limitation. The patent is therefore more naturally aligned with lower-dose tablets than with a 150 mg monthly product, unless the relevant product or claim construction treats the claimed amount differently.

This distinction matters because Boniva was marketed in both lower-dose daily and higher-dose monthly oral regimens. A competitor could potentially avoid claim 1 through a 150 mg tablet, a different coating composition or both.

What generic launch risks existed?

The patent created historical risk for a generic product only if the product and labeling met every material limitation. The risk profile was narrow:

Generic design	Risk under claim 1
Same four-component coating at substantially the claimed percentages	Higher historical risk
Different polymer, pigment, plasticizer or antiadherent	Lower risk
Same ingredients but materially different proportions	Potential noninfringement position
Ibandronate dose above 100 mg	Lower literal claim risk
Injectable ibandronate	Outside the oral-tablet limitation
Capsule, solution or other dosage form	Outside the tablet limitation
Label omitting the claimed indications	Potential method-of-use defense
Product launched after December 23, 2017	No infringement risk from this expired patent

A generic manufacturer would still need to evaluate other patents, regulatory exclusivity, product-specific labeling and possible state or federal litigation theories. Patent 6,143,326 alone does not block a current ibandronate launch.

Does biosimilar risk apply to ibandronate?

No. Ibandronate is a chemically synthesized small-molecule bisphosphonate. It is approved through the drug pathway and is subject to ANDA-based generic competition, not the biosimilar pathway used for biologic products under the Public Health Service Act.

The relevant competitors are generic ibandronate manufacturers, not biosimilar developers. Manufacturing know-how can affect cost, quality and regulatory execution, but it does not create biologic-style interchangeability barriers.

What manufacturing and geographic barriers remain?

The patent’s geographic protection was limited to the United States. It could not directly prevent production, sale or use outside the United States. Foreign counterparts would require separate analysis by country, including national-phase status, expiration, lapse and local regulatory rules.

The patent does not claim a manufacturing process. A manufacturer could potentially design around it by changing:

The film-coating excipients;
The proportions of the listed excipients;
The tablet dose;
The dosage form;
The release profile; or
The product label.

Any remaining manufacturing barrier would therefore arise from other patents, trade secrets, process validation, supplier qualification, formulation performance or FDA requirements, not from an active term under U.S. Patent 6,143,326.

What licensing deals affected Boniva commercialization?

Roche developed ibandronate and commercialized Boniva with GlaxoSmithKline in the United States under a co-promotion and commercialization arrangement reported publicly during the product’s market development. The commercial relationship did not extend the patent term and did not convert the formulation patent into a broader product monopoly.

No separate license is necessary to practice an expired U.S. patent. Historical licensing or co-promotion arrangements may remain commercially relevant for revenue attribution, but they do not create current exclusionary rights under 6,143,326.

Key Takeaways

U.S. Patent 6,143,326 claims a treatment method using a specific orally administered, coated ibandronate tablet.
The coating must be ibandronate-free and contain four ingredients in approximately stated percentages.
Claims 2 and 3 narrow the covered disease categories, with claim 3 naming hypercalcemia, osteoporosis, tumor osteolysis and Paget's disease.
The patent does not broadly cover all ibandronate products, all doses or all formulations.
It does not claim ibandronate as a compound or a manufacturing process.
The recorded expiration date is December 23, 2017.
The patent no longer creates a U.S. launch barrier or Paragraph IV risk.
Generic competition is governed by the ANDA pathway, not biosimilar regulation.
The strongest historical design-around strategies involved changing the coating composition, dose, dosage form or label.
Current commercial analysis should focus on generic manufacturing economics, FDA approvals, remaining product-specific patents and market demand rather than this expired patent.

FAQs About U.S. Patent 6,143,326

Can a generic ibandronate tablet infringe U.S. Patent 6,143,326 today?

No current infringement liability arises from practicing an expired patent, although historical conduct during the patent term could raise separate issues.

Does the patent cover 150 mg monthly ibandronate?

The claim expressly recites about 0.1 to 100 mg of ibandronate. A 150 mg tablet would not literally satisfy that dose limitation.

Is the patent a composition patent or a method patent?

It is a method-of-treatment patent. The formulation limitations define the tablet used in the claimed treatment method.

Can a tablet use the same coating ingredients in different percentages?

A materially different formulation may support a noninfringement position, but the effect of “about” requires analysis of the numerical deviation, specification, prosecution history and technical evidence.

Are ibandronate products subject to biosimilar competition?

No. Ibandronate is a small-molecule drug and competes through generic ANDA approvals rather than biosimilar applications.

References

U.S. Patent and Trademark Office. (2000). U.S. Patent No. 6,143,326, pharmaceutical compositions containing bisphosphonates. https://patents.google.com/patent/US6143326
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.fda.gov/drugs/drug-approvals-and-databases/approved-drug-products-therapeutic-equivalence-evaluations-orange-book
U.S. Food and Drug Administration. (2003). Boniva (ibandronate sodium) prescribing information, NDA 021455. https://www.accessdata.fda.gov/drugsatfda_docs/label/
U.S. Food and Drug Administration. (2024). Abbreviated new drug application approvals and patent certifications. https://www.fda.gov/drugs/abbreviated-new-drug-application-anda
U.S. Food and Drug Administration. (2024). Drugs@FDA: FDA-approved drugs database. https://www.accessdata.fda.gov/scripts/cder/daf/

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Germany	196 15 812	Apr 20, 1996

PCT Information
PCT Filed	April 21, 1997	PCT Application Number:	PCT/EP97/01940
PCT Publication Date:	October 30, 1997	PCT Publication Number:	WO97/39755

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	006652	⤷ Start Trial
Argentina	054350	⤷ Start Trial
Austria	404207	⤷ Start Trial
Australia	2638297	⤷ Start Trial
Australia	722516	⤷ Start Trial
Brazil	9708785	⤷ Start Trial
Canada	2251886	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 6,143,326

Summary for Patent: 6,143,326