US Patent 7,208,489: Palbociclib Claim Scope, Patent Expiration, Orange Book Status and Generic Risk

US Patent 7,208,489 is a foundational Pfizer patent covering the chemical class that includes palbociclib, marketed as Ibrance. Its strongest protection was the species-level coverage of palbociclib and pharmaceutically acceptable salts. The patent also includes a broad Markush genus, extensive compound listings, and a pharmaceutical-composition claim.

The patent expired on August 5, 2023, according to FDA Orange Book records. It no longer provides an enforceable U.S. patent barrier to generic palbociclib. Current generic-launch risk depends on later Pfizer patents, settlement agreements, regulatory exclusivities, and any remaining formulation, method-of-use, or manufacturing claims.

What drug does US Patent 7,208,489 protect?

US 7,208,489 covers 2-aminopyrido[2,3-d]pyrimidin-7-one compounds that act as cyclin-dependent kinase inhibitors. The commercial compound most closely associated with the patent is palbociclib.

Palbociclib is the compound identified in claim 8 as a pharmaceutically acceptable salt of:

6-acetyl-8-cyclopentyl-5-methyl-2-(5-piperazin-1-yl-pyridin-2-ylamino)-8H-pyrido[2,3-d]pyrimidin-7-one.

The structure corresponds to the active pharmaceutical ingredient in Ibrance, a CDK4/6 inhibitor approved by FDA for HR-positive, HER2-negative advanced or metastatic breast cancer in combination with endocrine therapies and, in certain settings, as monotherapy after prior endocrine therapy and chemotherapy exposure [1].

Item	Data
U.S. patent	7,208,489
Patent technology	2-aminopyrido[2,3-d]pyrimidin-7-one CDK inhibitors
Commercial compound	Palbociclib
Brand	Ibrance
Original patent owner	Warner-Lambert Company, later associated with Pfizer
U.S. issue date	April 24, 2007
FDA approval of Ibrance	February 3, 2015
Orange Book expiration	August 5, 2023
Current status of the ’489 patent	Expired
Dosage forms covered commercially	Capsules and tablets containing palbociclib

The patent is important because it claims the active chemical entity rather than only a formulation or a treatment method. That type of claim generally presents the most direct infringement risk for a generic product containing the same active ingredient.

How broad is claim 1 of US 7,208,489?

Claim 1 is a broad Markush compound claim. It covers a large chemical genus built around a substituted pyrido[2,3-d]pyrimidin-7-one core connected to an amino-substituted pyridine or related heteroaryl system.

The claim requires the following core elements:

A compound of formula I or a pharmaceutically acceptable salt.
A pyrido[2,3-d]pyrimidin-7-one-type scaffold.
Substituents X1, X2 and X3 with broad permissible chemical definitions.
At least one of X1, X2 and X3 must be hydrogen.
R1 as C1-C6 alkyl.
R3 as C1-C8 alkoxy, C3-C7 cycloalkyl, or C3-C7 heterocyclyl.
Broad substitution at R2 and R4.
Optional ring formation between R4 and one of X1, X2 or X3.
Pharmaceutically acceptable salts.

Chemical breadth of the Markush definitions

The claim permits a wide range of substituents, including:

Alkyl, haloalkyl, alkenyl and alkynyl groups
Cycloalkyl and heterocyclic groups
Alkoxy, hydroxyalkyl and alkoxyalkyl groups
Amines and substituted amino groups
Amides, sulfonamides and ureas
Esters, ketones and carboxylic acids
Sulfoxides and sulfones
Phosphonates
Aryl and heteroaryl groups
Bridged and tethered heterocyclic substituents

This drafting strategy attempts to capture both the original lead series and later medicinal-chemistry optimization around the CDK4/6 inhibitor scaffold.

The practical scope is narrower than the text may suggest. Every accused compound must satisfy the entire structural formula and all limitations. Broad substituent definitions do not remove the need to prove the required connectivity, ring system, substitution pattern and valence.

Which claims specifically cover palbociclib?

Claim 8 is the most commercially significant claim for palbociclib. It specifically covers a pharmaceutically acceptable salt of the palbociclib structure.

Claims 2 through 5 narrow the genus by imposing additional structural limitations:

Claim	Principal limitation
Claim 2	Specific structure shown in the patent, with substituents retained from formula I
Claim 3	R3 is cyclopentyl
Claim 4	R1 is methyl
Claim 5	R2 is acetyl, expressed as COCH3
Claim 6	Large list of specifically named compounds
Claim 7	Smaller list of named compounds and pharmaceutically acceptable salts
Claim 8	Pharmaceutically acceptable salt of the palbociclib compound
Claim 9	Pharmaceutical composition containing a claim 1 compound and carrier, diluent or excipient

Palbociclib satisfies the central narrowing pattern of:

Cyclopentyl substitution
Methyl substitution
Acetyl substitution
5-piperazin-1-yl-pyridin-2-ylamino substitution
Pyrido[2,3-d]pyrimidin-7-one core

Claims 6 and 7 contain numerous apparent duplicates and typographical variants. Their legal scope is determined by the issued patent, prosecution history and applicable claim-construction principles, not by an informal transcription.

What does claim 6 cover?

Claim 6 is a large species list. It names compounds containing several recurring structural variables:

6-acetyl, 6-bromo, 6-iodo and 6-(1-ethoxyvinyl) substituents
8-cyclopentyl substitution
5-methyl substitution
Pyridin-2-ylamino groups
Piperazine, morpholine, pyrrolidine, azepane and diazepane substituents
Amino, dialkylamino, hydroxyalkylamino and methoxyalkoxy groups
Carbonyl, sulfonyl and sulfonamide linkages
Protected amines, including tert-butoxycarbonyl-protected piperazines
Carboxylic acid and ester variants
Heteroaryl analogues, including naphthyridine derivatives

The list reflects a compound-library patent rather than a narrowly focused product patent. It attempts to preserve protection for multiple analogues that could have different potency, selectivity, solubility or pharmacokinetic characteristics.

From an enforcement perspective, a specifically named compound claim is usually easier to analyze than a broad genus claim. A product that matches a named species can face a clearer literal-infringement theory, subject to validity and enforceability defenses.

Does claim 9 cover Ibrance tablets and capsules?

Claim 9 covers a pharmaceutical composition containing a therapeutically effective amount of a claim 1 compound together with a carrier, diluent or excipient.

The claim can reach a finished dosage form containing palbociclib if:

The active ingredient satisfies claim 1.
The dosage form contains a pharmaceutical carrier, diluent or excipient.
The composition contains a therapeutically effective amount.

Claim 9 is weaker than the compound claim as a standalone barrier because an accused product may contest the composition limitations, claim construction or the scope of “therapeutically effective amount.” It also does not expressly claim a particular tablet, capsule, coating, dissolution profile, polymorph or excipient system.

The claim does not, by itself, create a distinct formulation patent covering every possible Ibrance formulation. It is a composition claim built on the claimed chemical genus.

When did US Patent 7,208,489 lose exclusivity?

The ’489 patent lost patent exclusivity on August 5, 2023. The date is the relevant Orange Book expiration date for the patent as listed against Ibrance [2].

Ibrance also received five-year new chemical entity exclusivity following FDA approval on February 3, 2015. That regulatory exclusivity ended in February 2020. NCE exclusivity prevented FDA approval of an ANDA or 505(b)(2) application relying on the listed drug during the applicable period, but it did not extend the patent term.

Exclusivity timeline

Date	Event
November 2000	Earliest priority period associated with the invention
April 24, 2007	US 7,208,489 issued
February 3, 2015	FDA approved Ibrance
February 2020	Five-year NCE exclusivity ended
August 5, 2023	Orange Book expiration of US 7,208,489
2023 onward	Generic applicants could challenge or design around the expired ’489 patent

The patent’s expiration does not establish that all palbociclib-related patents expired on the same date. Pfizer’s later patents may cover polymorphs, formulations, dosing regimens, combinations or other product attributes.

What is the Orange Book status of US 7,208,489?

The ’489 patent was listed in FDA’s Orange Book for Ibrance and is now expired. It was a drug-substance patent associated with palbociclib rather than a narrow patent limited to a particular dosage form.

The Orange Book distinction matters:

An active listed drug-substance patent can support a Paragraph IV certification and patent-infringement litigation.
An expired patent cannot independently support a current injunction against generic approval or launch.
Later-listed patents may still create litigation exposure if they cover the generic product, label or manufacturing process.
FDA patent listing does not determine validity or infringement.

FDA’s Orange Book data should be read together with the approved Ibrance labeling and Pfizer’s patent litigation filings [1, 2].

Which later patents create generic entry risk for palbociclib?

The main post-’489 risk categories are:

Formulation and solid-state patents

These patents may cover:

Crystalline palbociclib forms
Salt forms
Particle-size characteristics
Tablet or capsule compositions
Dissolution and bioavailability properties
Excipients and manufacturing conditions

A generic applicant can reduce risk by using a non-infringing polymorph, different excipient system or alternative manufacturing process, provided the resulting product remains pharmaceutically acceptable and bioequivalent.

Method-of-use patents

Palbociclib method patents may cover:

Treatment of HR-positive, HER2-negative breast cancer
Combination with letrozole
Combination with fulvestrant
Use after progression on endocrine therapy
Specific dosing schedules
Patient-selection criteria

These claims may be relevant even after the active-ingredient patent expires. A generic company may use a section viii “skinny label” to omit patented indications where FDA and applicable law permit that approach. The strategy is less effective where the remaining patented use is central to the product’s labeled market or where induced-infringement allegations are plausible.

Manufacturing and process patents

Process patents may cover:

Preparation of the pyridopyrimidinone core
Palladium-catalyzed coupling steps
Formation of piperazine-substituted intermediates
Salt isolation
Crystallization
Purification and scale-up

A process patent generally does not block a product made by an independent non-infringing route unless the patent also includes product-by-process or intermediate claims that reach the generic supply chain.

What Paragraph IV challenges affect Ibrance?

Generic palbociclib applicants have used Paragraph IV certifications against listed Ibrance patents. Public litigation involving Pfizer and generic applicants has included challenges by companies such as Teva Pharmaceuticals and other ANDA filers.

A Paragraph IV certification alleges that a listed patent is invalid, unenforceable or not infringed. The certification can trigger a 45-day period in which the patent owner may file an infringement action under the Hatch-Waxman Act. Filing the action can impose a statutory stay of FDA approval for up to 30 months, subject to court decisions and statutory exceptions [3].

The ’489 patent itself is no longer a meaningful Paragraph IV obstacle because it has expired. The litigation value shifted to later patents with later expiration dates.

Generic litigation issues

Issue	Relevance to palbociclib
Invalidity	Broad genus claims may face enablement, written-description and obviousness challenges
Non-infringement	Generic may use a different salt, polymorph, formulation or process
Label carve-out	May remove patented combination or treatment uses
30-month stay	Can delay FDA approval after timely infringement litigation
Settlement	May establish an agreed generic launch date before later patent expiry
At-risk launch	Generic launches before final resolution and accepts possible damages or injunction risk

How strong is the patent estate for palbociclib?

The ’489 patent was strong during its enforceable term because it combined a broad genus with direct coverage of the commercial compound. Its strength is now historical rather than operative.

Strength assessment

Feature	Assessment
Compound claim	Strong during term; now expired
Species claim to palbociclib	Strongest claim category in the patent
Salt coverage	Broad but dependent on the salt falling within the claim
Composition claim	Moderate; requires proof of composition limitations
Method-of-use coverage	Not present as a central feature of the asserted claims
Formulation coverage	Limited in the ’489 claims
Manufacturing coverage	Not the principal focus of the claims provided
Generic relevance today	Low for direct patent blocking; high for historical validity and priority analysis

The broad genus could have been vulnerable to written-description and enablement attacks if asserted against a structurally remote compound. Those defenses are less important for palbociclib itself because the patent identifies the commercial species directly in the claims and describes a large number of related examples.

How does US 7,208,489 compare with later palbociclib patents?

The ’489 patent is primarily a chemical-entity patent. Later patents generally pursue incremental exclusivity around the approved product.

Patent category	Typical protected subject matter	Generic design-around potential
’489 compound patent	Palbociclib and broad CDK inhibitor genus	None for the exact compound after expiration
Solid-state patent	Polymorph, crystal form or salt	Moderate to high, depending on bioequivalence
Formulation patent	Tablet, capsule, excipient or dissolution profile	Moderate
Method patent	Cancer indication, combination or dosing regimen	High through label carving in some cases
Process patent	Synthetic route or intermediate	Moderate to high
Composition patent	Active ingredient with carrier	Depends on excipient and dosage-form limitations

A generic palbociclib product must be assessed against the entire active patent estate, not only against US 7,208,489. The commercial question is whether a generic can obtain approval and launch without infringing enforceable later patents or violating a settlement restriction.

Are biosimilars relevant to the patent landscape?

No. Palbociclib is a small-molecule chemical drug, not a biologic. Biosimilar provisions under the Biologics Price Competition and Innovation Act do not apply.

The relevant competitors are:

ANDA-based generic manufacturers
505(b)(2) applicants, if relying on a different formulation or route
Authorized generic suppliers
International suppliers seeking U.S. market entry
Combination-product or co-packaging competitors

Generic applicants must demonstrate pharmaceutical equivalence and bioequivalence under the ANDA pathway. They do not need to repeat the full clinical efficacy program conducted for Ibrance.

What generic launch scenarios exist after expiration?

Immediate launch after clearance

A generic could launch after the ’489 patent expired if no enforceable later patent covered the product, label or manufacturing process and the applicant had final FDA approval.

Launch after settlement

A settlement may authorize entry on a negotiated date before the latest asserted patent expires. The economic value depends on whether the settlement grants an exclusive first launch, a non-exclusive launch right or an authorized-generic arrangement.

Skinny-label launch

A generic may omit patented indications or dosing instructions from its label where the carve-out is legally and regulatorily effective. This strategy is more viable where the uncarved indication supports a commercially meaningful market.

At-risk launch

A company may launch before final resolution of later patent litigation. It may then face damages, an injunction or a forced withdrawal if Pfizer prevails.

Non-infringing reformulation

A company may use a different crystalline form, salt, excipient combination or manufacturing process. This approach can reduce patent exposure but creates regulatory and technical work, particularly where changes affect dissolution, stability or bioequivalence.

What licensing deals and commercial relationships affect Ibrance?

Palbociclib originated from the Warner-Lambert research organization and became part of Pfizer’s portfolio through Pfizer’s acquisition of Warner-Lambert. The ’489 patent is therefore associated with Pfizer’s successor rights rather than with an independent third-party licensee.

The patent record does not establish a material external license that would change ownership of the U.S. ’489 patent. Commercial supply, authorized-generic and settlement arrangements must be evaluated separately from patent ownership.

Ibrance has been a major Pfizer oncology product. Pfizer reported Ibrance revenue of approximately $4.8 billion in 2023 and approximately $4.1 billion in 2024, reflecting substantial exposure to generic erosion after loss of core exclusivity [4, 5]. The exact erosion rate depends on the timing and scale of generic entry, payer substitution, authorized-generic strategy and the durability of later patents.

What geographic coverage does the patent provide?

US 7,208,489 provides U.S. rights only. It does not itself create protection in Europe, Japan, China, Canada or other markets.

The invention may have corresponding international family members, but each jurisdiction has separate:

Claim language
Validity standards
Patent-term calculations
Supplementary protection or regulatory extensions
Litigation history
Patent listings
Generic-approval rules

A U.S. expiration date cannot be applied to foreign family members. International freedom-to-operate analysis requires a jurisdiction-by-jurisdiction review of granted claims and national-phase status.

Key Takeaways

US 7,208,489 is a foundational palbociclib compound patent.
Claim 1 covers a broad CDK inhibitor Markush genus.
Claims 6 and 7 list numerous specific pyrido[2,3-d]pyrimidin-7-one compounds.
Claim 8 directly covers a pharmaceutically acceptable salt of palbociclib.
Claim 9 covers pharmaceutical compositions containing compounds within claim 1.
The ’489 patent expired on August 5, 2023.
The patent no longer independently blocks generic palbociclib entry.
Later formulation, solid-state, method-of-use and process patents may remain commercially relevant.
Paragraph IV litigation has shifted from the expired core compound patent to later-listed patents.
Biosimilar law is irrelevant because palbociclib is a small molecule.
Pfizer’s principal exposure is generic erosion of Ibrance revenue, not loss of biologic exclusivity.

FAQs

What is the chemical name of palbociclib in US Patent 7,208,489?

The claimed palbociclib structure is 6-acetyl-8-cyclopentyl-5-methyl-2-(5-piperazin-1-yl-pyridin-2-ylamino)-8H-pyrido[2,3-d]pyrimidin-7-one, including pharmaceutically acceptable salts.

Is US 7,208,489 still enforceable against generic Ibrance?

No. The patent expired on August 5, 2023. Any current restriction on generic Ibrance must arise from another enforceable patent, regulatory exclusivity or contractual settlement provision.

Does the ’489 patent cover palbociclib polymorphs?

It covers palbociclib and pharmaceutically acceptable salts within the claim language. It is not principally a polymorph patent. Specific crystalline forms may be covered by later patents.

Can a generic omit the Ibrance breast-cancer indication?

A generic may be able to use a section viii label carve-out for patented indications or dosing regimens. The result depends on the listed patent claims, FDA labeling and the wording of the proposed generic label.

Is palbociclib subject to biosimilar competition?

No. Palbociclib is a synthetic small-molecule drug and competes through the ANDA generic pathway rather than the biosimilar pathway.

References

U.S. Food and Drug Administration. (2024). Ibrance (palbociclib) prescribing information. FDA.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.
U.S. Government Publishing Office. (2024). 21 U.S.C. § 355(j): Abbreviated applications for new drugs. United States Code.
Pfizer Inc. (2024). 2023 annual report. Pfizer.
Pfizer Inc. (2025). 2024 annual report. Pfizer.
United States Patent and Trademark Office. (2007). U.S. Patent No. 7,208,489: 2-aminopyrimidine compounds as cyclin-dependent kinase inhibitors. USPTO.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	1470124	⤷ Start Trial	300863	Netherlands	⤷ Start Trial
European Patent Office	1470124	⤷ Start Trial	122017000014	Germany	⤷ Start Trial
European Patent Office	1470124	⤷ Start Trial	PA2017013	Lithuania	⤷ Start Trial
European Patent Office	1470124	⤷ Start Trial	C20170012 00212	Estonia	⤷ Start Trial
European Patent Office	1470124	⤷ Start Trial	CA 2017 00010	Denmark	⤷ Start Trial
European Patent Office	1470124	⤷ Start Trial	12/2017	Austria	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Summary for Patent: 7,208,489