Details for Patent: 12,077,533

Which drugs does patent 12,077,533 protect, and when does it expire?

Patent 12,077,533 protects LITFULO and is included in one NDA.

This patent has seventy-one patent family members in forty-six countries.

Summary for Patent: 12,077,533

Title:	Pyrrolo[2,3-d]pyrimidinyl, pyrrolo[2,3-b]pyrazinyl and pyrrolo[2,3-d]pyridinyl acrylamides
Abstract:	The present invention provides a method for treating alopecia using certain pharmaceutically active pyrrolo[2,3-d]pyrimidinyl acrylamides having the structure:or a pharmaceutically acceptable salt thereof, as set forth in the Description.
Inventor(s):	Atli Thorarensen, Matthew Frank Brown, Agustin Casimiro-Garcia, Ye CHE, Jotham Wadsworth Coe, Mark Edward Flanagan, Adam Matthew Gilbert, Matthew Merrill Hayward, Jonathan David Langille, Justin Ian Montgomery, Jean-Baptiste Telliez, Rayomand Jal Unwalla, John I Trujillo
Assignee:	Pfizer Inc
Application Number:	US17/393,463
Patent Claim Types: see list of patent claims	Use;

US Patent 12,077,533: Scope, Claims, Exclusivity, and Ritlecitinib Patent Landscape

US Patent 12,077,533 protects methods of treating alopecia with a broad genus of kinase-inhibitor compounds and, specifically, with ritlecitinib. Claim 1 is a structurally broad Markush method claim. Claim 2 is narrower and covers the administration of ritlecitinib itself, the active ingredient in Pfizer’s Litfulo product. The patent is a method-of-use asset, not the principal composition-of-matter patent for ritlecitinib.

Because the chemical drawing referenced in claim 1 is not reproduced in the supplied text, the full ring system and attachment points cannot be mapped conclusively. Claim 2 nevertheless identifies the commercial compound and permits a reliable analysis of the principal infringement and competitive issues.

What drug does US Patent 12,077,533 protect?

US Patent 12,077,533 protects therapeutic use of ritlecitinib and related substituted heterocyclic kinase inhibitors for alopecia.

The specific compound in claim 2 is:

1-((2S,5R)-5-(7H-pyrrolo[2,3-d]pyrimidin-4-ylamino)-2-methylpiperidin-1-yl)prop-2-en-1-one

That compound is ritlecitinib, marketed by Pfizer as Litfulo. Ritlecitinib is an oral irreversible inhibitor of Janus kinase 3 and the TEC-family kinases. FDA approved Litfulo on June 23, 2023, for the treatment of severe alopecia areata in adults and adolescents 12 years and older [2].

Item	Information
Active ingredient	Ritlecitinib
Brand	Litfulo
Sponsor	Pfizer
Product type	Oral small molecule
FDA indication	Severe alopecia areata
FDA approval	June 23, 2023
Dosage form	Capsules
Standard adult dose	50 mg once daily
Patent at issue	US 12,077,533
Claim category	Method of treatment
Primary target class	JAK3 and TEC-family kinases

The patent does not claim only the FDA-approved 50 mg capsule regimen. Claim 2 covers administering the identified compound in a therapeutically effective amount. It does not expressly limit treatment to a particular dose, dosing schedule, capsule strength, age group, severity threshold, or route of administration.

What does claim 1 cover?

Claim 1 covers a method of treating alopecia by administering a therapeutically effective amount of a broad chemical genus to a mammal.

The claim has four principal elements:

1. A method for treating alopecia.
2. A mammal in need of treatment.
3. Administration of a therapeutically effective amount.
4. A compound having the specified scaffold and the listed substituent definitions, or a salt, solvate, enantiomer, or diastereomer.

The Markush language covers extensive substitution at R2, R3, R0, R1, R4, R6, R8, R9, R10, Ra, Rb, Rc, and Rd. The permitted substituents include:

• Hydrogen and deuterium.
• Linear and branched C1-C6 alkyl groups.
• Perfluoroalkyl groups.
• C3-C6 cycloalkyl groups.
• Aryl and heteroaryl groups.
• Alkoxy, amino, hydroxyl, cyano, carboxy, and halogen substituents.
• Sulfoxide, sulfone, sulfonamide, and urea-related substituents.
• Alkyl-substituted aryl, heteroaryl, and heterocyclic groups.
• Fused or bridged ring systems formed by selected substituent pairs.

The claim also expressly includes pharmaceutically acceptable salts and solvates, as well as enantiomers and diastereomers. That language expands the claim beyond a single neutral molecule and creates potential coverage for pharmaceutical forms that contain the same active chemical entity in a different solid-state or stereochemical form.

How broad is the chemical genus?

The genus is potentially large. Its practical scope depends on the chemical structure omitted from the supplied claim text, the allowed valence of each ring position, and the relationship between the listed substituent variables and the core scaffold.

The legal scope is narrower than the substituent list alone suggests. A potentially infringing compound must satisfy all structural limitations, not merely share a pyrrolopyrimidine moiety or kinase activity. The compound must also be used in a method for treating alopecia.

The claim does not appear to require:

• A specific kinase inhibition profile.
• A particular JAK3 or TEC-family selectivity ratio.
• A defined alopecia subtype.
• A specified treatment duration.
• A specified patient age.
• A particular formulation.
• A demonstrated level of hair regrowth.

Those omissions increase the potential reach of the method claim but may create enablement, written-description, definiteness, or claim-construction issues if the genus is challenged.

What does claim 2 cover?

Claim 2 is a species claim directed to ritlecitinib itself.

A party practicing all of the following steps would fall within the literal language of claim 2:

• Identifying a mammal in need of alopecia treatment.
• Administering ritlecitinib or a pharmaceutically acceptable salt.
• Administering a therapeutically effective amount.
• Using the compound to treat alopecia.

Claim 2 is materially easier to analyze than claim 1 because the chemical identity is fixed. It does not depend on whether a later compound falls within the Markush genus.

The principal limitation is the treatment purpose. Sale or manufacture of ritlecitinib, without evidence of use for alopecia, is not itself an act directly recited by claim 2. In practice, however, an approved alopecia product label, prescribing information, promotional material, or induced-use theory may provide evidence relevant to method-of-use enforcement.

What forms of alopecia are covered?

The claim uses the unqualified term “alopecia.” That wording is broader than the FDA-approved indication for Litfulo.

Potentially relevant conditions include:

• Alopecia areata.
• Severe alopecia areata.
• Alopecia totalis.
• Alopecia universalis.
• Other autoimmune or inflammatory hair-loss conditions, subject to claim construction and enablement.
• Potentially androgenetic or pattern hair loss if the claim’s disclosure supports that use.

The FDA label limits Litfulo’s approved indication to severe alopecia areata in patients at least 12 years old [2]. The patent claim itself does not include those restrictions. This creates a separation between regulatory scope and patent scope.

A generic or competing product marketed for a different alopecia subtype may still face risk if the patented method reasonably encompasses that use and the product labeling or conduct supports induced infringement. Conversely, a broad patent claim does not automatically establish infringement for every hair-loss use. The actual indication, label language, physician instructions, and evidence of intent remain material.

What patents protect Litfulo and ritlecitinib?

Ritlecitinib is likely protected by a layered estate rather than by US 12,077,533 alone.

Protection layer	Typical subject matter	Strategic value
Composition of matter	Ritlecitinib and related kinase inhibitors	Broadest product protection
Salt and stereochemical claims	Specific salt, enantiomer, or crystalline form	Limits alternative product presentations
Pharmaceutical composition	Ritlecitinib with excipients or dosage forms	Protects commercial formulations
Method of treatment	Alopecia treatment using ritlecitinib	Supports indication-specific enforcement
Manufacturing process	Intermediates, coupling reactions, purification, crystallization	Raises design-around and supply-chain barriers
Regulatory exclusivity	New chemical entity and related FDA exclusivity	Delays ANDA approval independently of patent validity

US 12,077,533 is most significant as an alopecia method patent. It should be analyzed together with Pfizer’s composition-of-matter and formulation patents, because a generic company may need to overcome all unexpired listed patents before launching without an infringement injunction or settlement.

What is the Orange Book status of Litfulo?

Litfulo is an FDA-approved small-molecule drug regulated through the NDA pathway, not a biologic regulated under the biosimilar pathway. Relevant patents may be listed in the FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations, commonly known as the Orange Book, if they claim the drug substance, drug product, or approved method of use [3].

Orange Book listing has commercial consequences:

• An ANDA applicant must address each listed patent.
• A Paragraph IV certification alleges that a listed patent is invalid, unenforceable, or not infringed.
• The NDA holder may sue within the statutory period after receiving a Paragraph IV notice.
• Timely litigation can trigger a 30-month stay of ANDA approval under the Hatch-Waxman framework.
• A successful first Paragraph IV filer may qualify for 180-day generic exclusivity, subject to statutory forfeiture rules.

A method patent is not automatically Orange Book-listable. Listing depends on whether the patent claims an FDA-approved method of using the drug and whether the FDA determines that the statutory listing requirements are met. The patent’s commercial significance therefore depends on its actual listing status, not merely its existence in the US patent record.

When does Litfulo lose regulatory exclusivity?

FDA approved Litfulo on June 23, 2023. Ritlecitinib received new chemical entity exclusivity, which generally prevents submission of an ANDA containing a Paragraph IV certification during the first four years and prevents approval during the full five-year period, subject to statutory exceptions [2, 4].

Event	Date or period
FDA approval	June 23, 2023
Four-year ANDA submission bar	Generally ends June 23, 2027
Five-year NCE approval bar	Generally ends June 23, 2028
Patent-based blocking period	Depends on listed patent expiration, litigation, and settlements

An ANDA applicant may be able to submit a Paragraph IV application during the final year of NCE exclusivity, but FDA approval generally cannot occur until the five-year period expires unless an exception applies.

Regulatory exclusivity is separate from patent protection. Even after NCE exclusivity ends, unexpired patents may prevent approval or expose the applicant to litigation. Conversely, invalidating or designing around patents does not eliminate the statutory NCE period.

When do the key Litfulo patents expire?

The relevant expiration analysis requires reviewing each patent’s earliest effective nonprovisional priority date, patent-term adjustment, patent-term extension, terminal disclaimers, and any continuation relationship.

US 12,077,533 should not be treated as the only relevant expiration date. The practical loss-of-exclusivity date is the latest enforceable barrier that covers the proposed generic product or its intended use.

Estimated patent-term framework

For a US utility patent, the ordinary term is 20 years from the earliest effective nonprovisional filing date for the application family, subject to statutory adjustments [4]. A patent may therefore expire materially later than the FDA’s five-year NCE period.

Key term variables include:

• The earliest priority application that begins the 20-year term.
• Patent-term adjustment for USPTO examination delay.
• Terminal disclaimers linking continuation patents to an earlier patent.
• Patent-term extension under 35 U.S.C. § 156.
• Post-grant proceedings and enforceability rulings.
• Settlement agreements that defer generic launch beyond the nominal patent term.

The exact expiration date for US 12,077,533 must be taken from the USPTO patent-term data and any terminal-disclaimer record. The issue date alone does not establish the patent’s expiration date.

What Paragraph IV challenges could target Litfulo?

A generic applicant could challenge Litfulo patents through several theories:

Invalidity

Potential arguments include:

• Lack of written description for the breadth of the Markush genus.
• Lack of enablement across the full range of compounds and alopecia conditions.
• Obviousness based on known JAK, TEC, or pyrrolopyrimidine kinase inhibitors.
• Anticipation by earlier disclosed compounds or treatment methods.
• Indefiniteness in functional or structural limitations.
• Double-patenting if a continuation claim overlaps an earlier family claim.

Noninfringement

A proposed product could argue that:

• The active compound falls outside the claimed structure.
• The product uses a nonclaimed salt or formulation.
• The label does not direct treatment of alopecia.
• The proposed indication is outside the claim.
• The administered amount is not therapeutically effective for the claimed condition.
• The accused conduct does not satisfy the mammal-in-need or treatment limitations.

Claim-scope vulnerability

Claim 2 is narrower chemically but stronger on identity. A challenger cannot avoid it merely by using a different ritlecitinib salt if the claim expressly covers pharmaceutically acceptable salts. Claim 1 presents a broader invalidity risk because its genus may encompass a large number of compounds and disease applications.

What formulation patents protect Litfulo?

US 12,077,533 does not appear, from the supplied claims, to require a specific formulation. It therefore does not directly recite:

• A 50 mg capsule.
• Particular excipients.
• A dissolution profile.
• A particle-size distribution.
• A crystalline polymorph.
• A controlled-release system.
• A specific manufacturing process.

Any separate formulation or solid-state patent would need to be analyzed independently. A generic capsule could avoid a formulation claim while still infringing claim 2 if it administers ritlecitinib for alopecia. Conversely, a generic formulation might avoid claim 2 only if it does not practice the claimed therapeutic use or uses a chemically different active ingredient.

Are biosimilars a risk for ritlecitinib?

No. Ritlecitinib is a chemically synthesized small molecule, not a therapeutic protein. The principal competitive threat is an ANDA-based generic, not a biosimilar under the Public Health Service Act.

Generic entry depends on:

• NCE exclusivity.
• Orange Book-listed patents.
• Paragraph IV certifications.
• Hatch-Waxman litigation.
• Patent settlements.
• The ability to produce ritlecitinib at commercial scale.
• Any active pharmaceutical ingredient or process patents.

Which companies are likely to challenge Litfulo?

Generic pharmaceutical companies with established small-molecule ANDA capabilities are the likely challengers. Public identification of a specific challenger requires an actual Paragraph IV notice, ANDA litigation complaint, or settlement disclosure. The patent claims alone do not establish that a particular company has filed a challenge.

Potential commercial entry routes include:

1. A full-label ANDA for severe alopecia areata.
2. A carve-out label omitting patented alopecia uses, if FDA requirements permit.
3. A Paragraph IV challenge to composition, method, formulation, or process patents.
4. A delayed-entry settlement.
5. A post-expiration launch after patent invalidation or noninfringement findings.

For a drug approved only for alopecia areata, a skinny-label strategy may be difficult if the principal approved indication is itself the patented use. The practical value of a carve-out depends on which patents are listed and whether the remaining label still permits a commercially viable indication.

How strong is the patent estate?

The estate is strongest against a direct generic copy of ritlecitinib labeled for alopecia treatment.

Strengths

• Claim 2 identifies the active compound with chemical precision.
• The patent expressly covers pharmaceutically acceptable salts.
• Claim 1 extends beyond ritlecitinib to a broader compound genus.
• The method claims do not appear limited to the commercial 50 mg strength.
• The patent complements, rather than replaces, composition and regulatory protection.

Vulnerabilities

• The supplied version omits the chemical drawing needed to assess claim 1 fully.
• Broad genus coverage can invite written-description and enablement challenges.
• A method claim requires proof of the claimed treatment use.
• Claim 2 may have limited value against a product sold without an alopecia indication if induced infringement cannot be established.
• Patent-term and Orange Book value depend on the actual family record and listing status.

Overall, claim 2 is the clearest enforcement claim for a ritlecitinib product used to treat alopecia. Claim 1 has greater theoretical breadth but presents a larger validity and construction surface.

What patent litigation or settlements affect Litfulo?

The existence of US 12,077,533 does not by itself establish litigation. A complete litigation assessment requires review of district court complaints, PTAB proceedings, Paragraph IV notices, FDA listing data, and any publicly disclosed settlement.

The principal litigation questions are:

• Whether US 12,077,533 is listed in the Orange Book.
• Whether a Paragraph IV notice has been served.
• Whether Pfizer filed a timely infringement action.
• Whether the patent is subject to a 30-month stay.
• Whether a settlement establishes a licensed or agreed launch date.
• Whether a terminal disclaimer links the patent to an earlier Pfizer patent.
• Whether any inter partes review or post-grant challenge has been filed.

A settlement may preserve a nominal patent right while allowing an agreed generic entry date earlier than the patent’s stated expiration. Revenue modeling should therefore use the settlement date, if any, rather than relying only on the face expiration date.

What generic launch risks exist for Litfulo?

The principal launch scenarios are:

Scenario	Commercial consequence
No timely Paragraph IV challenge	Entry generally deferred until patent and exclusivity barriers expire
Successful Paragraph IV challenge	Potential launch after litigation victory, subject to remaining patents
30-month stay	FDA approval delayed during qualifying litigation
Skinny-label launch	Possible only if patented uses can be omitted without retaining the infringing indication
Settlement	Launch date depends on negotiated terms
Authorized generic	Pfizer or a licensee may compete during or after exclusivity
Patent invalidation	Earlier entry and substantial price erosion
Manufacturing challenge	Approval may be delayed despite legal clearance

For revenue exposure, a first generic typically causes rapid price erosion and share transfer, although the pace varies by pharmacy benefit manager coverage, generic supplier count, and the number of approved ANDAs. Litfulo’s commercial exposure is concentrated in the severe alopecia areata market because that is its current approved indication.

How does US 12,077,533 compare with a composition-of-matter patent?

Issue	US 12,077,533	Composition-of-matter patent
Subject	Treatment of alopecia	Chemical compound itself
Direct product coverage	Limited	Broad
Need to prove treatment use	Yes	Usually no for product manufacture or sale
Ritlecitinib coverage	Express in claim 2	Depends on compound claim
Design-around potential	Higher	Lower
Orange Book relevance	Depends on listing	Usually strong if drug substance is claimed
Commercial leverage	Indication-specific	Product-wide
Typical vulnerability	Use, enablement, induced infringement	Prior art, obviousness, structure

A generic may avoid a method patent through a label carve-out, but it generally cannot avoid a valid composition-of-matter claim while selling the same active ingredient. For this reason, US 12,077,533 should be viewed as an important layer of protection rather than the sole barrier to generic ritlecitinib.

Key Takeaways

• US 12,077,533 is a method-of-treatment patent directed to alopecia.
• Claim 2 specifically covers ritlecitinib, the active ingredient in Litfulo.
• Claim 1 covers a broader genus of substituted kinase-inhibitor compounds, including salts, solvates, enantiomers, and diastereomers.
• The claims are not limited to the FDA-approved 50 mg dose or to patients 12 years and older.
• The patent is distinct from composition, formulation, manufacturing, and FDA exclusivity rights.
• Litfulo received FDA approval on June 23, 2023, with the standard five-year NCE framework generally extending through June 23, 2028.
• Generic competition is expected to proceed through the ANDA and Paragraph IV framework, not the biosimilar pathway.
• Claim 2 presents the clearest infringement risk for a ritlecitinib product labeled for alopecia.
• The commercial value of the patent depends heavily on Orange Book listing, patent-term data, related Pfizer patents, and any Paragraph IV settlement.
• The omitted chemical drawing prevents a complete claim-construction analysis of the full scope of claim 1.

FAQs

Does US Patent 12,077,533 cover Litfulo’s 50 mg capsule?

Claim 2 covers ritlecitinib used to treat alopecia, regardless of whether the product is administered as a 50 mg capsule. The claim does not expressly require the 50 mg strength.

Can a generic avoid US 12,077,533 by using a different ritlecitinib salt?

Not necessarily. Claim 2 expressly includes pharmaceutically acceptable salts. A different salt may avoid a separate formulation or solid-state claim, but it may remain within claim 2.

Does the patent cover alopecia universalis?

The claim uses the broader term “alopecia” and does not expressly limit treatment to severe alopecia areata. Whether alopecia universalis falls within the claim would depend on claim construction, specification support, and infringement facts.

Is ritlecitinib subject to biosimilar competition?

No. Ritlecitinib is a small-molecule drug. Competition would ordinarily proceed through an ANDA-based generic pathway.

Can a generic launch before 2028 if it invalidates the patents?

FDA’s NCE exclusivity is separate from patent validity. Even if patents are invalidated, the five-year NCE approval bar generally remains unless a statutory exception applies.

References

1. United States Patent and Trademark Office. (2024). U.S. Patent No. 12,077,533: Methods of treating alopecia. U.S. Department of Commerce.

2. U.S. Food and Drug Administration. (2023). Litfulo (ritlecitinib) prescribing information. Pfizer Laboratories.

3. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. U.S. Department of Health and Human Services.

4. United States Code. (2024). 35 U.S.C. §§ 154, 156, 271, 282, and 355. U.S. Government Publishing Office.

Drugs Protected by US Patent 12,077,533

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Pfizer	LITFULO	ritlecitinib tosylate	CAPSULE;ORAL	215830-001	Jun 23, 2023		RX	Yes	Yes						METHOD OF TREATING SEVERE ALOPECIA AREATA IN ADULTS AND ADOLESCENTS 12 YEARS AND OLDER BY ADMINISTERING RITLECTINIB

International Family Members for US Patent 12,077,533

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	3077395		301245	Netherlands
European Patent Office	3077395		CA 2023 00028	Denmark
European Patent Office	3077395		LUC00322	Luxembourg
European Patent Office	3077395		PA2023537	Lithuania
European Patent Office	3077395		2023C/544	Belgium