Details for Patent: 9,079,928

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Which drugs does patent 9,079,928 protect, and when does it expire?

Patent 9,079,928 protects AZSTARYS and is included in one NDA.

This patent has fifty-six patent family members in twenty-nine countries.

Summary for Patent: 9,079,928

Title:	Methylphenidate-oxoacid conjugates, processes of making and using the same
Abstract:	The present technology is directed to prodrugs and compositions for the treatment of various diseases and/or disorders comprising methylphenidate, or methylphenidate derivatives, conjugated to at least one alcohol, amine, oxoacid, thiol, or derivatives thereof. In some embodiments, the conjugates further include at least one linker. The present technology also relates to the synthesis of methylphenidate, or methylphenidate derivatives, conjugated to at least one alcohol, amine, oxoacid, thiol, or derivatives thereof or combinations thereof.
Inventor(s):	Sven Guenther, Guochen Chi, Bindu Bera, Travis Mickle, Sanjib Bera
Assignee:	Zevra Therapeutics Inc
Application Number:	US14/234,440
Patent Claim Types: see list of patent claims	Composition; Formulation; Compound; Dosage form;

US Patent 9,079,928: Methylphenidate Prodrug Claims, Exclusivity, and Patent Landscape

US Patent 9,079,928 protects a class of methylphenidate prodrug compositions in which methylphenidate is covalently linked to an amino acid through an amide bond. The broadest claim is not limited to serdexmethylphenidate, a particular salt, dosage form, stereoisomer, release profile, or therapeutic indication. Claims 2 and 3 narrow the amino-acid component to threonine and serine. Claims 5 through 8 cover salt forms and pharmaceutical presentations.

The patent is commercially important because it is associated with the methylphenidate prodrug technology used in AZSTARYS, a combination product containing serdexmethylphenidate and immediate-release dexmethylphenidate. The patent is a small-molecule composition patent, not a biologic patent. Generic competition would proceed through the ANDA pathway rather than biosimilar procedures.

What does US Patent 9,079,928 protect?

The patent protects compositions containing at least one methylphenidate-amino-acid conjugate. The operative structural limitation is that the amino acid is attached to the remainder of the methylphenidate-derived molecule through an amide linkage.

The claim architecture is:

Claim	Subject matter	Scope
1	Methylphenidate conjugate with standard, nonstandard, or synthetic amino acid	Broad composition claim
2	Claim 1 conjugate using threonine	Species claim
3	Claim 1 conjugate using serine	Species claim
4	Specific structures identified in the patent	Structural species or subgenus
5	Pharmaceutically acceptable anionic, amphoteric, zwitterionic, or cationic salts	Salt-form claim
6	Extensive list of acid-addition or related salt forms	Specific salt limitations
7	Metal, ammonium, amino, and related cationic forms	Specific counterion limitations
8	Tablets, capsules, films, patches, liquids, inhaled products, suppositories, and other dosage forms	Pharmaceutical presentation claim
9	Additional structurally defined amino-acid conjugate	Structural species or subgenus

Claims 1 and 9 use the same general amino-acid concept, but claim 9 also appears to impose the structural limitation represented by the omitted chemical drawing. The exact scope of claim 9 depends on the structure shown in the issued patent.

How broad is claim 1 of US 9,079,928?

Claim 1 is the principal composition claim. It has four important breadth characteristics.

First, it covers “at least one” conjugate. A composition may therefore contain one covered conjugate or multiple covered conjugates, subject to the remaining claim limitations.

Second, the amino acid is defined functionally and categorically. The claim includes standard amino acids, nonstandard amino acids, and synthetic amino acids. The claim is not limited to serine or threonine.

Third, the claim requires an amide bond between the amino acid and the remainder of the molecule. A formulation containing methylphenidate merely mixed with a free amino acid would not satisfy this limitation. The components must be covalently linked in the claimed manner.

Fourth, the claim is a composition claim. It does not expressly require:

• A particular dosage strength
• A particular oral or nonoral delivery route
• A specified pharmacokinetic profile
• Conversion to active methylphenidate in vivo
• A particular medical indication
• A particular excipient
• A particular manufacturing process
• A specific salt form

Those limitations appear in narrower dependent claims or may be relevant to infringement and validity analysis.

Does US 9,079,928 cover serdexmethylphenidate?

The patent is relevant to serdexmethylphenidate because serdexmethylphenidate is a methylphenidate prodrug containing an amino-acid-derived conjugate. FDA identifies serdexmethylphenidate as the prodrug component of AZSTARYS, which also contains dexmethylphenidate hydrochloride [2].

Claim 3 expressly recites serine. If the marketed serdexmethylphenidate structure falls within the specific stereochemical and connectivity requirements of the issued claims, the patent provides a direct composition claim covering the active prodrug. The commercial analysis must distinguish between:

1. The broad generic amino-acid genus in claim 1;
2. The serine species in claim 3;
3. The specific structural claims in claims 4 and 9; and
4. Any separately listed patents covering AZSTARYS, its formulation, or its method of use.

The chemical drawings for claims 4 and 9 are not reproduced in the supplied text. The precise mapping of serdexmethylphenidate to those claims therefore depends on the issued patent drawings and the molecule’s stereochemical designation.

What formulations are protected by US 9,079,928?

Claim 8 extends the composition claims into multiple dosage forms. It recites tablets, capsules, caplets, troches, lozenges, oral powders, solutions, thin strips, oral thin films, oral strips, rectal films, transdermal patches, syrups, suspensions, inhalation compounds, and suppositories.

The formulation claim is broad in dosage-form coverage but does not independently protect every formulation containing methylphenidate. It depends on claim 1. A formulation must contain the claimed amino-acid-linked methylphenidate conjugate.

The claim does not require:

• A specific release technology
• A particular polymer
• A defined particle size
• A specified ratio of prodrug to active methylphenidate
• A particular coating
• A particular excipient system
• A particular dissolution profile

A product could avoid claim 8 by omitting the claimed conjugate, even if it uses the same dosage form. Conversely, a product using a tablet or oral film may fall within claim 8 if it contains a qualifying conjugate.

What is the scope of the salt claims?

Claims 5 through 7 attempt to cover a wide range of pharmaceutically acceptable salt forms.

Claim 5 covers anionic, amphoteric, zwitterionic, and cationic salt forms. Claim 6 lists numerous counterions, including hydrochloride, hydrobromide, sulfate, phosphate, citrate, fumarate, maleate, succinate, tartrate, acetate, mesylate, besylate, tosylate, and others. Claim 7 lists cationic forms involving sodium, potassium, calcium, magnesium, zinc, aluminum, lithium, cholinium, lysine, ammonium, and tromethamine.

Several drafting issues are commercially relevant:

• The heading “anionic salt form” in claim 6 does not align cleanly with every listed salt.
• Some listed counterions appear repeated.
• Certain terms appear to contain typographical errors, such as “methylsufate,” “tribrophenate,” and “Martrate.”
• The list includes forms that may be chemically or commercially impractical for a given methylphenidate conjugate.
• The claim’s enforceability depends on how the specification defines “pharmaceutically acceptable” and how a court construes the listed forms.

The salt claims are most valuable where a commercial product uses a specific salt that is not independently claimed in a later patent. They also increase the number of potential claim-chart permutations in an ANDA dispute.

When does US Patent 9,079,928 lose exclusivity?

The patent was issued on July 14, 2015. Public patent records identify an expected expiration in April 2028, based on the underlying priority and patent-term calculation [1].

Event	Date
Earliest relevant priority period	2008
Patent issued	July 14, 2015
Expected expiration	April 2028
Commercial relevance	AZSTARYS and related methylphenidate prodrug technology

The effective loss of market protection may occur earlier than the nominal patent expiration if:

• A generic applicant receives approval after a successful Paragraph IV challenge;
• The patent is invalidated or found not infringed;
• A settlement permits an earlier launch;
• A later-listed patent imposes a separate regulatory stay;
• The relevant product is not covered by the patent claims.

The 30-month ANDA stay is tied to the timing of a Paragraph IV notice and patent litigation, not automatically to the patent’s expiration date.

What is the Orange Book status of US 9,079,928?

US 9,079,928 has been associated with AZSTARYS in FDA patent-listing materials. AZSTARYS was approved by FDA in May 2021 for attention deficit hyperactivity disorder in patients six years of age and older [2].

AZSTARYS contains:

• Serdexmethylphenidate, a prodrug component; and
• Dexmethylphenidate hydrochloride, the immediately active methylphenidate component.

The patent’s principal Orange Book value is its potential coverage of the prodrug active ingredient rather than ordinary immediate-release dexmethylphenidate. A generic product containing only dexmethylphenidate would not ordinarily practice the amino-acid-conjugate limitations of claims 1 through 9.

Orange Book relevance must be separated from patent validity. FDA listing does not establish that every claim is valid or infringed. It identifies patents submitted by the NDA holder or identified patent owner as relating to the approved drug.

What Paragraph IV challenges affect the patent?

A generic applicant can challenge an Orange Book-listed patent by filing a Paragraph IV certification stating that the patent is invalid, unenforceable, or would not be infringed by the proposed ANDA product.

The key litigation questions would be:

1. Whether the ANDA product contains a methylphenidate-amino-acid conjugate;
2. Whether the conjugate uses the claimed amide linkage;
3. Whether the amino-acid component falls within the standard, nonstandard, or synthetic categories;
4. Whether the product uses a claimed serine or threonine species;
5. Whether the product uses a listed salt;
6. Whether the product’s dosage form satisfies claim 8;
7. Whether the claims are enabled across the full amino-acid genus;
8. Whether the claims have adequate written-description support;
9. Whether claim terms such as “pharmaceutically acceptable” and “conjugate” are indefinite; and
10. Whether prosecution-history estoppel narrows the claims.

A conventional generic methylphenidate product would have a strong non-infringement position because it lacks the covalent amino-acid conjugate. A generic applicant attempting to copy serdexmethylphenidate would face a materially different risk profile.

Which companies are challenging the patent?

The commercial rights are associated with KemPharm’s methylphenidate prodrug platform and Corium’s commercialization of AZSTARYS. Public FDA and patent records should be reviewed for the current ANDA applicant, Paragraph IV notices, and district-court complaints before relying on a company-specific challenge assessment.

The relevant competitive groups are:

Competitor group	Product type	Exposure to US 9,079,928
Immediate-release methylphenidate generics	Conventional methylphenidate	Generally low
Extended-release methylphenidate products	Formulation-based methylphenidate	Generally low unless they use the conjugate
Serdexmethylphenidate imitators	Same or similar prodrug	High
Alternative stimulant products	Amphetamine, lisdexamfetamine, or other stimulant	No direct infringement absent the claimed conjugate
Nonstimulant ADHD products	Atomoxetine, viloxazine, guanfacine, clonidine	No direct patent overlap

The most credible Paragraph IV threat is a product specifically designed to replicate the prodrug component rather than a conventional methylphenidate generic.

How strong is the patent estate for the methylphenidate prodrug?

The patent has meaningful composition-claim strength but also presents potential validity vulnerabilities.

Strengths

• Claim 1 reaches a broad amino-acid genus.
• Claim 3 identifies serine, the amino acid most commercially relevant to serdexmethylphenidate.
• The claims cover salts and multiple dosage forms.
• Composition claims do not depend on proving a particular therapeutic use.
• A copied prodrug molecule may be difficult to design around without changing the covalent architecture.

Potential weaknesses

• The genus in claim 1 is broad.
• The patent must support standard, nonstandard, and synthetic amino acids across the claimed scope.
• Structural claims may depend heavily on omitted chemical drawings and stereochemistry.
• The salt list contains drafting inconsistencies.
• A challenger could argue lack of written description or enablement for the full genus.
• A competitor could select a different prodrug architecture, a non-amide linkage, or a non-amino-acid promoiety.
• A conventional methylphenidate formulation can avoid the claims by omitting the conjugate entirely.

The strongest practical claims are likely the narrower claims directed to the commercially used molecular species and its relevant pharmaceutical salt, rather than the full genus in claim 1.

How does US 9,079,928 compare with competing ADHD drug patents?

US 9,079,928 differs from the core patent strategies used for most ADHD products.

Product or technology	Primary protection type	Relationship to US 9,079,928
AZSTARYS	Methylphenidate prodrug plus immediate-release dexmethylphenidate	Directly relevant
Concerta	Extended-release methylphenidate delivery system	Different technology
Ritalin LA and other ER products	Release profile and formulation	Usually outside the amino-acid conjugate claims
Vyvanse	Lisdexamfetamine prodrug	Different active ingredient and prodrug
Jornay PM	Delayed-release and extended-release methylphenidate formulation	Different formulation strategy
Qelbree	Viloxazine extended release	No direct structural overlap
Strattera	Atomoxetine	No direct structural overlap

The patent’s competitive significance comes from protecting a new methylphenidate molecular entity rather than merely protecting a release mechanism.

What generic launch scenarios exist?

Three scenarios define the commercial risk.

Scenario 1: Conventional methylphenidate entry

A manufacturer launches an ordinary methylphenidate or dexmethylphenidate product. This product generally does not practice the amino-acid conjugate claims. The patent has limited blocking power against that launch.

Scenario 2: Prodrug-specific ANDA

A manufacturer develops a serdexmethylphenidate-equivalent product and files an ANDA with a Paragraph IV certification. This creates direct validity and infringement exposure under claims 1, 3, 5, 8, and potentially 9.

Scenario 3: Non-infringing prodrug design

A competitor uses a different promoiety, a different linkage, or a different chemical strategy to control methylphenidate release. That product may avoid literal infringement but would require separate FDA, toxicology, chemistry, and clinical development work.

The third scenario is technically possible but commercially more expensive than copying an established prodrug platform.

Are biosimilar risks relevant?

No. Serdexmethylphenidate is a chemically synthesized small molecule. A competing product would use the generic-drug framework under section 505(j) of the Federal Food, Drug, and Cosmetic Act, not the biosimilar framework under section 351(k) of the Public Health Service Act.

The relevant regulatory risks are ANDA patent certification, pharmaceutical equivalence, bioequivalence, chemistry and manufacturing controls, and any product-specific exclusivity. Biosimilar interchangeability and reference-biologic issues do not apply.

What manufacturing and intellectual-property barriers remain?

The patent claims create a molecular design barrier, but they do not independently cover every manufacturing step. A competitor may still need to address:

• Selective formation of the amide linkage;
• Control of methylphenidate stereochemistry;
• Removal of unreacted amino acid and methylphenidate;
• Control of regioisomers and diastereomers;
• Salt selection and crystallization;
• Conversion kinetics to active methylphenidate;
• Stability under formulation and storage conditions;
• Impurity qualification;
• Scale-up and batch consistency;
• Patent claims covering intermediates, processes, formulations, and methods of use.

Manufacturing patents not identified in the supplied claims may create separate barriers. US 9,079,928 should therefore be treated as one component of the estate, not as a complete freedom-to-operate conclusion.

Key Takeaways

• US 9,079,928 claims methylphenidate conjugated to an amino acid through an amide linkage.
• Claim 1 is a broad genus claim covering standard, nonstandard, and synthetic amino acids.
• Claims 2 and 3 narrow the invention to threonine and serine.
• Claims 5 through 7 cover broad categories of pharmaceutically acceptable salts.
• Claim 8 extends coverage to numerous dosage forms, including tablets, capsules, oral films, patches, liquids, inhalation products, and suppositories.
• The patent is commercially relevant to serdexmethylphenidate and AZSTARYS.
• Conventional methylphenidate generics generally present limited infringement risk because they do not contain the claimed covalent conjugate.
• A serdexmethylphenidate-equivalent product would face direct Paragraph IV, validity, and infringement issues.
• The expected patent expiration is in April 2028, subject to the applicable patent-term calculation.
• Biosimilar analysis is not relevant because the technology is a small-molecule drug.

FAQs About US Patent 9,079,928

Does US 9,079,928 cover methylphenidate hydrochloride?

Not by itself. The claims require a methylphenidate-amino-acid conjugate with an amide linkage. Ordinary methylphenidate hydrochloride lacks that claimed conjugate structure.

Does the patent cover a free mixture of methylphenidate and serine?

No. The claims require covalent attachment through an amide linkage. A physical mixture of methylphenidate and serine would not satisfy that structural limitation.

Can a generic company avoid US 9,079,928 by using a different salt?

Possibly, but changing the salt may not avoid the broader composition claims. Claims 1 through 3 do not appear limited to a particular salt. A different salt could still infringe if the underlying methylphenidate-amino-acid conjugate falls within claim 1.

Is AZSTARYS protected only by US 9,079,928?

No. AZSTARYS may be associated with multiple patents covering the active ingredients, formulations, methods of treatment, or related technology. The patent analyzed here should not be treated as the complete AZSTARYS patent estate.

Does a patent expiration in 2028 guarantee generic entry?

No. Generic entry also depends on FDA approval, patent litigation, settlement terms, regulatory exclusivity, any later-listed patents, manufacturing readiness, and the scope of the proposed generic product.

References

1. United States Patent and Trademark Office. (2015). Methylphenidate prodrugs, U.S. Patent No. 9,079,928.
2. U.S. Food and Drug Administration. (2021). AZSTARYS (serdexmethylphenidate and dexmethylphenidate) prescribing information. Corium, Inc.
3. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
4. U.S. Food and Drug Administration. (2024). Electronic Orange Book patent and exclusivity information.
5. U.S. Patent and Trademark Office. (2024). Patent term adjustment and patent-term information resources.

Drugs Protected by US Patent 9,079,928

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Commave Sub	AZSTARYS	dexmethylphenidate hydrochloride; serdexmethylphenidate chloride	CAPSULE;ORAL	212994-001	May 7, 2021		RX	Yes	No			Y
Commave Sub	AZSTARYS	dexmethylphenidate hydrochloride; serdexmethylphenidate chloride	CAPSULE;ORAL	212994-002	May 7, 2021		RX	Yes	No			Y
Commave Sub	AZSTARYS	dexmethylphenidate hydrochloride; serdexmethylphenidate chloride	CAPSULE;ORAL	212994-003	May 7, 2021		RX	Yes	Yes			Y

Foreign Priority and PCT Information for Patent: 9,079,928

PCT Information
PCT Filed	July 27, 2012	PCT Application Number:	PCT/US2012/048641
PCT Publication Date:	January 31, 2013	PCT Publication Number:	WO2013/016668

International Family Members for US Patent 9,079,928

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	087390
Australia	2012286683
Brazil	112014002084
Canada	2837732
Canada	2984544
Canada	3123900
Chile	2014000210