US Patent 7,135,489: Valdecoxib Crystalline Form Claims, Scope, Expiration, and Patent Landscape

US Patent 7,135,489 protected a specific crystalline form of valdecoxib, the active ingredient formerly marketed by Pfizer as Bextra. The patent did not broadly claim valdecoxib, its chemical structure, or every solid form. Its claims focused on one crystalline form identified through infrared spectroscopy, powder X-ray diffraction, and differential scanning calorimetry.

The patent issued on November 14, 2006, and its 20-year term ran from the relevant January 31, 2002 U.S. nonprovisional filing date, subject to any patent-term adjustment. Public patent records list the patent as expired, with no current enforceable U.S. exclusivity from US 7,135,489. The patent was commercially important when Bextra was marketed, but it no longer creates a present generic-entry barrier. [1]

What drug and crystalline form does US 7,135,489 cover?

The claimed compound is valdecoxib, chemically identified as 4-[5-methyl-3-phenylisoxazol-4-yl]benzenesulfonamide. Valdecoxib is a selective cyclooxygenase-2 inhibitor. Pfizer marketed it in the United States as Bextra for acute pain, primary dysmenorrhea, and osteoarthritis and rheumatoid arthritis symptoms before its withdrawal from the U.S. market in 2005. [2]

US 7,135,489 is a solid-state patent. It covers a defined crystalline form rather than the active pharmaceutical ingredient in every physical state.

Item	Patent information
U.S. patent	7,135,489
Title	Crystalline form of valdecoxib
Active ingredient	Valdecoxib
Chemical name	4-[5-methyl-3-phenylisoxazol-4-yl]benzenesulfonamide
Patent type	Polymorph and pharmaceutical-composition patent
Issue date	November 14, 2006
Patent holder and commercial sponsor	Searle-related Pfizer interests
Primary technology	Crystalline form identification and pharmaceutical compositions
U.S. status	Expired
Commercial product	Bextra
Dosage forms relevant to product	Oral tablets

The patent is narrower than a basic compound patent. A valdecoxib product that does not contain the claimed crystal form would fall outside the literal scope of the crystal-form claims, although infringement could still arise under other patents or through formulation, manufacturing, or induced-infringement theories.

What are the independent claims in US 7,135,489?

The patent’s principal independent claims are claims 1, 2, 3, 7, 8, and 9. Claims 5, 6, 10, and 11 cover pharmaceutical compositions containing the claimed crystalline material.

Claim	Analytical limitation	Scope
1	IR peaks at 3377, 1170, 1151, 925, 844, 745, 729, and 534 cm⁻¹	Crystal form identified by a specified infrared spectrum
2	XRPD peaks at about 12.2, 15.4, 15.8, 17.1, 19.8, 22.0, 23.6, 23.9, and 24.6° 2θ	Crystal form identified by a broader powder diffraction pattern
3	XRPD peaks at 12.221, 15.447, 17.081, 19.798, and 23.861° 2θ	Crystal form identified by a more specific set of diffraction peaks
4	Claim 2 form lacking a significant IR peak at 723 cm⁻¹	Subform distinguished from a form showing the 723 cm⁻¹ peak
7	DSC onset around 170.9°C and peak around 172.5°C	Crystal form identified by thermal behavior
8	At least three selected IR peaks	Broad analytical genus based on partial IR identity
9	At least three selected XRPD peaks	Broad analytical genus based on partial XRPD identity
5, 6	Composition containing the claim 2 crystalline form	Pharmaceutical composition claims
10	Composition containing the claim 8 form and an acceptable carrier, adjuvant, or diluent	Formulation claims
11	Composition containing the claim 9 form and an acceptable carrier, adjuvant, or diluent	Formulation claims

The supplied claim text lists claims 5 and 6 as identical. That duplication may reflect a transcription error, a database rendering issue, or the issued claim language. The operative scope should be confirmed against the certified patent document before use in litigation or a freedom-to-operate opinion. [1]

How broad are the crystalline-form claims?

The claims vary materially in breadth.

Claim 1: full infrared fingerprint

Claim 1 requires the claimed crystalline form to have all eight listed IR peaks. The claim is relatively specific because a competing solid form would need to show the required spectral pattern to fall within its literal language.

The key infringement issue would be analytical reproducibility. Peak position, intensity, sample preparation, instrument calibration, polymorph mixtures, and detection thresholds can affect an IR spectrum. The claim does not appear to require a particular peak intensity ratio, which may create a broader practical boundary than a fully quantified spectral fingerprint.

Claims 2 and 3: powder X-ray diffraction identity

Claim 2 requires a set of approximate XRPD peaks. Claim 3 recites five more precise peak positions. Claim 2 is broader in its use of "about" and in the number of listed peaks. Claim 3 is narrower as to peak position but may still cover the same commercial crystal form.

XRPD claims generally turn on whether the accused material produces the claimed diffraction peaks under comparable testing conditions. The analysis must account for:

Instrument wavelength and calibration;
Sample orientation and preferred orientation;
Peak-shift tolerances;
Amorphous content;
Mixtures of polymorphs;
Hydrates, solvates, and desolvated forms;
Relative peak intensity and detection limits.

A product containing a mixture of the patented form and another form can create infringement risk if the patented form remains present in a commercially meaningful or legally detectable amount. The claim language supplied does not establish a minimum concentration threshold.

Claim 4: absence of a 723 cm⁻¹ peak

Claim 4 adds a negative spectral limitation. It covers the claim 2 form that lacks a significant IR peak at approximately 723 cm⁻¹. This limitation can distinguish the claimed form from another valdecoxib polymorph with a meaningful peak at that location.

The phrase "significant peak" is technically consequential. It requires a threshold or analytical interpretation, but the claim as supplied does not state a numerical intensity cutoff. That creates potential claim-construction and reproducibility issues.

Claims 7, 8, and 9: thermal and partial-pattern claims

Claim 7 uses DSC to define the form through a melting onset near 170.9°C and a peak near 172.5°C. DSC results can vary with heating rate, sample mass, pan configuration, purity, and instrument calibration.

Claims 8 and 9 are materially broader than claims 1 through 3 because they require only three selected peaks. They may capture materials that share a limited subset of the patented form’s spectral or diffraction pattern without reproducing the entire fingerprint. Their practical validity would depend on the specification’s disclosure, the meaning of "comprising," analytical tolerances, and whether the selected peaks reliably distinguish the claimed form from other valdecoxib forms.

What formulations are protected by US 7,135,489?

The composition claims cover a pharmaceutical composition containing a therapeutically effective amount of the claimed crystalline form. Claims 10 and 11 also require at least one pharmaceutically acceptable carrier, adjuvant, or diluent.

The patent therefore reaches formulations such as tablets, capsules, powders, and other oral dosage forms if they contain the claimed crystalline valdecoxib form. The claims do not appear to require a particular excipient, dosage strength, release profile, tablet geometry, or manufacturing process.

The formulation claims are not independent protection for every valdecoxib product. They depend on the presence of the specified crystalline form. A formulation using valdecoxib in an amorphous state, a different polymorph, or a noninfringing solid form would not automatically satisfy these claims.

When did US 7,135,489 lose exclusivity?

The patent’s U.S. term has expired. The relevant timeline is:

Date	Event
January 31, 2002	U.S. nonprovisional filing date reflected in public patent records
November 14, 2006	Patent issued
May 2005	FDA requested withdrawal of Bextra from the U.S. market
January 31, 2022	Expected end of the standard 20-year patent term, subject to any adjustment
Current status	Expired; no current exclusivity from this patent

The patent’s expiration is separate from Bextra’s regulatory withdrawal. The FDA withdrawal removed the marketed product from the U.S. market, while patent expiration removed the legal exclusion right after the patent term ended. [1, 2]

What was the Orange Book status of valdecoxib and Bextra?

Bextra was approved under NDA 21-341. The FDA later requested withdrawal of valdecoxib because the benefit-risk profile was unfavorable, particularly in light of cardiovascular, gastrointestinal, and serious skin-reaction concerns. Pfizer withdrew Bextra from the U.S. market in 2005. [2]

The Orange Book status of a withdrawn product must be evaluated separately from patent status. A withdrawn NDA can remain historically relevant in FDA records, but it does not create a current commercial market for an ANDA applicant. Orange Book-listed patents also do not extend beyond their statutory term.

US 7,135,489 is best treated as a historical product patent connected to Bextra and valdecoxib solid-form protection. It should not be treated as a currently enforceable Orange Book barrier without a current FDA listing and unexpired patent record. [3]

Did US 7,135,489 create Paragraph IV risk?

During the patent term, an ANDA applicant seeking approval for a valdecoxib product could have faced Paragraph IV issues if the reference listed patent covered the proposed product. The applicant would need to address whether its product contained the claimed crystalline form and whether the patent was invalid, unenforceable, or not infringed.

After expiration, Paragraph IV certification to this patent no longer creates the same litigation exposure. A generic applicant could instead rely on patent expiration, subject to any other unexpired patents, regulatory exclusivity, or product-specific FDA requirements.

No biosimilar pathway applies. Valdecoxib is a small-molecule drug, not a biologic. The relevant competitive pathway would have been an ANDA under section 505(j), or potentially a 505(b)(2) application for a product with a different formulation, indication, or clinical strategy. [4]

Which companies challenged or litigated valdecoxib patent rights?

The major publicly documented valdecoxib legal event was not a generic patent challenge but the FDA-driven withdrawal of Bextra. Public records associated with US 7,135,489 do not establish a current infringement case involving the patent.

The commercial parties connected to the patent estate included:

G.D. Searle LLC and related Searle entities as research and patent-origin organizations;
Pharmacia, which became part of Pfizer;
Pfizer, as Bextra sponsor and commercial owner;
Potential generic manufacturers that could have evaluated valdecoxib after patent expiration or during the patent term.

The absence of a current litigation barrier is commercially important. A historical Paragraph IV case, if any, would not restore an expired patent or revive Bextra’s withdrawn U.S. marketing authorization.

How strong was the patent estate for valdecoxib?

The estate had several layers:

Protection layer	Strategic purpose	Current position
Basic chemical compound patents	Protect valdecoxib molecule and related isoxazole compounds	Historical; relevant terms expired or became commercially ineffective
Crystalline-form patents	Protect selected polymorphs, including US 7,135,489	US 7,135,489 expired
Formulation patents	Protect tablets, excipients, dosage forms, or release characteristics	Must be assessed patent by patent
Method-of-use patents	Protect treatment of pain, inflammation, dysmenorrhea, or related conditions	Historical and indication-specific
Regulatory exclusivity	Protect FDA approval period	No current Bextra commercial exclusivity
Manufacturing patents	Protect crystallization, purification, or process conditions	Requires separate claim review

US 7,135,489 was technically useful because solid-form patents can complicate generic development even when the underlying compound patent is near expiration. The claims required analytical comparison of the generic’s active ingredient. That can affect crystallization conditions, drying, milling, particle-size control, stability testing, and formulation development.

Its present strength is limited by expiration and the withdrawal of Bextra. The patent remains relevant for historical patent landscaping, validity analysis, and freedom-to-operate records, but it does not provide an active U.S. exclusion right.

How does valdecoxib compare with competing COX-2 drugs?

Drug	Sponsor history	U.S. commercial status	Patent-landscape implication
Valdecoxib	Pfizer, formerly Searle/Pharmacia	Bextra withdrawn in 2005	Historical crystal-form and method-of-use estate
Celecoxib	Pfizer	Marketed as Celebrex and available generically	Active commercial market with separate compound, formulation, and use patents
Rofecoxib	Merck	Withdrawn in 2004	Historical patent estate; no current U.S. marketed product
Etoricoxib	Merck	Not approved in the United States	Foreign-market patent and regulatory analysis required

The principal commercial substitute in the United States became celecoxib. Valdecoxib’s patent position cannot be used as a proxy for celecoxib’s patent position because the molecules, FDA approvals, patent families, and litigation histories differ.

What generic-entry risks remain?

The US 7,135,489 risk is zero as an active patent barrier because the patent has expired. Residual risks could arise from other sources:

Other unexpired U.S. patents covering valdecoxib, if any.
FDA requirements for a withdrawn NDA or a new approval pathway.
Clinical and safety requirements associated with COX-2 inhibition.
Manufacturing controls needed to produce a stable and reproducible solid form.
Foreign patents in jurisdictions where a valdecoxib product remains commercially relevant.
Product-liability and pharmacovigilance exposure.

The manufacturing barrier was potentially more significant during the patent term than after expiration. A generic developer would need to control polymorph formation because crystallization conditions can change solvent content, particle morphology, dissolution, stability, and bioavailability. Those technical constraints can persist after patent expiration even when they no longer constitute legal exclusivity.

Key Takeaways

US 7,135,489 covers a specific crystalline form of valdecoxib, not valdecoxib in every physical form.
The claims rely on IR spectroscopy, XRPD, DSC, and pharmaceutical-composition limitations.
Claims 8 and 9 are broader because they require only selected subsets of IR or XRPD peaks.
Claims 5, 6, 10, and 11 extend protection to pharmaceutical compositions containing the claimed solid form.
The patent issued on November 14, 2006, and is now expired.
Bextra was withdrawn from the U.S. market in 2005 after FDA safety concerns.
The patent no longer creates a current U.S. Paragraph IV or generic-entry barrier.
Valdecoxib is a small molecule, so biosimilar analysis does not apply.
Remaining risk must be assessed against the broader valdecoxib patent family, FDA status, foreign rights, and manufacturing patents.

FAQs

What is US Patent 7,135,489 commonly called?

It is commonly identified as a crystalline-form or polymorph patent for valdecoxib, the active ingredient in Bextra.

Does US 7,135,489 cover generic valdecoxib automatically?

No. It covers valdecoxib having specified IR, XRPD, or DSC characteristics, plus compositions containing that form. A generic product using another noninfringing solid form would not automatically fall within the claims.

Is valdecoxib still protected by a U.S. compound patent?

The principal U.S. compound and use patents associated with the original Bextra program are historical. A current freedom-to-operate review must confirm every relevant patent family and terminal disclaimer, but US 7,135,489 itself is expired.

Can a company develop a valdecoxib product after the patent expiration?

Patent expiration removes this patent barrier, but a company would still need an FDA approval pathway and would need to address valdecoxib’s safety history, regulatory status, manufacturing controls, and any remaining patents.

Does the patent cover amorphous valdecoxib?

The claims supplied are directed to crystalline material identified by specified analytical properties. Amorphous valdecoxib would generally fall outside those claims unless the accused material also satisfies the claimed spectral or thermal limitations.

References

United States Patent and Trademark Office. (2006). U.S. Patent No. 7,135,489, Crystalline form of valdecoxib.
U.S. Food and Drug Administration. (2005). FDA public health advisory: Bextra (valdecoxib).
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
U.S. Food and Drug Administration. (2024). Abbreviated new drug application (ANDA) process.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
African Regional IP Organization (ARIPO)	1055	⤷ Start Trial
African Regional IP Organization (ARIPO)	9901458	⤷ Start Trial
Argentina	009244	⤷ Start Trial
Austria	228117	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 7,135,489

Summary for Patent: 7,135,489