US Patent 10,512,609: Solriamfetol Tablet Claims, Exclusivity, and Generic Entry Risk

US Patent 10,512,609 protects a specific immediate-release solriamfetol hydrochloride tablet and methods of using that tablet. The patent does not broadly claim every solriamfetol product. Its commercial significance is concentrated in tablets containing approximately 90% to 98% active ingredient, a limited binder and lubricant system, rapid dissolution, and substantially pH-independent dissolution across pH 1.2, 4.5, and 6.8.

The patent is relevant to Sunosi, Jazz Pharmaceuticals’ branded solriamfetol product for excessive daytime sleepiness associated with narcolepsy or obstructive sleep apnea. The principal generic-entry risk concerns an ANDA product that uses the same active ingredient, strength, excipient architecture, immediate-release design, and dissolution profile.

What drug and product does US Patent 10,512,609 cover?

US Patent 10,512,609 covers tablets containing the R-enantiomer of 2-amino-3-phenylpropyl carbamate, generally known as solriamfetol, particularly solriamfetol hydrochloride.

The patent claims a treatment method using an immediate-release compressed tablet with the following core attributes:

Claim element	Required limitation
Active ingredient	Pharmaceutically acceptable salt of (R)-2-amino-3-phenylpropyl carbamate
Active loading	About 90% to 98% by tablet weight
Binder	About 1% to 5% by tablet weight
Lubricant	About 0.1% to 2% by tablet weight
Release rate	At least 85% released in less than 15 minutes
Dissolution behavior	Substantially identical dissolution at pH 1.2, 4.5, and 6.8
Dosage form	Immediate-release compressed tablet
Primary salt	Solriamfetol hydrochloride
Commercial strengths recited in claims	Approximately 37.5 mg, 75 mg, 150 mg, and 300 mg

The claim language corresponds closely to the formulation architecture of Sunosi tablets, which are supplied in 37.5 mg, 75 mg, 150 mg, and 300 mg strengths.[2]

What are the independent claims in US Patent 10,512,609?

Claim 1 is the principal independent claim. It is a method-of-treatment claim requiring administration of the specified tablet for one or more listed conditions or for smoking cessation.

The covered indications include:

Narcolepsy
Cataplexy
Excessive daytime sleepiness
Drug addiction
Sexual dysfunction
Fatigue
Fibromyalgia
Attention deficit/hyperactivity disorder
Restless legs syndrome
Depression
Bipolar disorder
Obesity
Smoking cessation

The claim requires both a therapeutic indication and a tablet having the specified formulation and dissolution characteristics. A product that contains solriamfetol but does not meet the tablet limitations falls outside the literal scope of claim 1.

The claim is therefore narrower than a general composition claim covering solriamfetol hydrochloride. It combines:

A particular active pharmaceutical ingredient.
A high drug-load tablet.
Defined binder and lubricant ranges.
Immediate-release performance.
Rapid release within 15 minutes.
Comparable dissolution across three pH environments.
Administration for a listed medical use.

How do claims 2 through 16 narrow the patent scope?

The dependent claims impose additional formulation, dosing, physical, and strength limitations.

Claim	Added limitation	Commercial relevance
2	Once-daily administration	Covers a principal Sunosi dosing pattern
3	More-than-once-daily administration	Preserves broader dosing coverage
4	At least 95% released in less than 15 minutes	Higher dissolution-performance threshold
5	No disintegrant	Important formulation restriction
6	Specified binder classes	Defines permissible excipient families
7	Specified lubricant classes	Defines permissible lubricant families
8	Hydroxypropyl cellulose binder and magnesium stearate lubricant	Closely tracks a specific formulation
9	Tablet may have a coating	Covers coated tablets
10	Coating is a color overcoat	Protects commercial appearance and identification
11	Salt is solriamfetol hydrochloride	Narrows the active form
12	Oblong tablet	Protects a physical product characteristic
13	Approximately 300 mg	Covers the highest marketed strength
14	Approximately 150 mg	Covers the principal adult strength
15	Approximately 75 mg	Covers the lower marketed strength
16	Approximately 37.5 mg	Covers the lowest marketed strength

Claim 8 is commercially important because it identifies hydroxypropyl cellulose and magnesium stearate, the same general excipient combination reflected in the claim set’s preferred formulation. Claims 13 through 16 map the patent to the marketed dosage-strength range.

What formulations are protected by US Patent 10,512,609?

The strongest formulation coverage is directed to a high-load, low-excipient tablet.

A formulation within the core claim profile would generally contain:

Solriamfetol hydrochloride at approximately 90% to 98% by weight.
Hydroxypropyl cellulose at approximately 1% to 5%.
Magnesium stearate at approximately 0.1% to 2%.
No disintegrant, if claim 5 is being asserted.
An immediate-release tablet matrix.
Optional color overcoat.
Rapid dissolution at multiple physiologic and analytical pH values.

The patent does not require every listed binder or lubricant. Claims 6 and 7 provide Markush alternatives. A tablet using povidone instead of hydroxypropyl cellulose, or sodium stearyl fumarate instead of magnesium stearate, could still fall within the broader dependent-claim framework if all other limitations are met.

The critical technical limitation is not merely the excipient identity. It is the combination of excipient ranges and dissolution performance. A generic manufacturer could attempt to avoid infringement by changing the binder, lubricant, active loading, tablet design, or dissolution profile. That approach may create regulatory or bioequivalence challenges because the product must still perform comparably to the reference listed drug.

How strong is the patent estate for Sunosi?

The Sunosi patent estate has several layers:

Protection layer	Relevance
Active-ingredient patents	Protect solriamfetol or related chemical compounds
Method-of-use patents	Protect treatment of excessive daytime sleepiness and related conditions
Formulation patents	Protect the immediate-release tablet architecture
Dosage-strength claims	Cover 37.5 mg, 75 mg, 150 mg, and 300 mg tablets
Regulatory exclusivity	Delays ANDA approval independent of patent validity
Orange Book listings	Trigger Paragraph IV notice and 30-month stay mechanisms

US Patent 10,512,609 is principally a formulation and method-of-use patent. It is more vulnerable to a non-infringing formulation design than a patent claiming the active compound itself. Its commercial strength comes from the difficulty of reproducing a high-drug-load tablet with rapid, pH-independent dissolution while maintaining acceptable manufacturing and bioequivalence performance.

The broad list of indications increases theoretical claim scope but does not eliminate the need to prove that the accused product meets the formulation and dissolution limitations.

When does US Patent 10,512,609 expire?

The patent issued on December 24, 2019.[1] Its effective term is based on the relevant US nonprovisional filing date, subject to patent-term adjustment, terminal disclaimers, and any applicable patent-term extension.

The patent has a nominal expiration horizon in 2037. The precise terminal date should be taken from the USPTO patent-term record because the issue date alone does not determine expiration.

Milestone	Date or status
Patent	US 10,512,609
Issue date	December 24, 2019
Patent type	US utility patent
Product association	Solriamfetol hydrochloride tablets, including Sunosi
Nominal term horizon	2037
Patent-term adjustment	Must be checked in the USPTO record
Patent-term extension	No conclusion should be drawn from the claims alone

The patent’s practical exclusivity may end earlier than its nominal expiration if an ANDA applicant prevails in litigation, obtains a non-infringement judgment, or develops a product outside the asserted claim limitations.

What is the Orange Book status of US Patent 10,512,609?

FDA’s Orange Book identifies patents submitted by the NDA holder or patent owner as applicable to approved drug products.[3] Sunosi is approved under NDA 211230 for excessive daytime sleepiness associated with narcolepsy or obstructive sleep apnea.[2]

US Patent 10,512,609 has been associated with the Sunosi patent estate. Its relevance to an ANDA depends on whether FDA lists it for the applicable NDA and whether the generic applicant must certify against it.

An ANDA applicant generally has four certification options:

The patent information is not applicable.
The patent has expired.
The applicant will not market before patent expiration.
The applicant challenges the patent through a Paragraph IV certification.

A Paragraph IV certification can trigger patent litigation. If the NDA holder files suit within the statutory period after receiving notice, FDA approval may be stayed for up to 30 months, subject to litigation outcomes and statutory exceptions.

Are there Paragraph IV challenges to Sunosi patents?

A Paragraph IV challenge would likely target one or more of the following issues:

Whether the accused tablet meets the “about 90-98%” active-loading range.
Whether the accused product contains a qualifying binder and lubricant.
Whether the release requirement is satisfied in less than 15 minutes.
Whether dissolution is “substantially identical” at pH 1.2, 4.5, and 6.8.
Whether the ANDA label induces infringement of a claimed indication.
Whether the claims are anticipated or obvious in view of earlier solriamfetol formulations.
Whether the patent adequately supports the full breadth of its listed indications.

No publicly established final invalidity or non-infringement ruling against US Patent 10,512,609 is reflected in the patent record cited here. The absence of a final ruling does not establish that no Paragraph IV notice has been submitted. Paragraph IV notices are often disclosed through litigation filings, SEC reports, FDA actions, or company announcements rather than the patent document itself.

What generic launch risks exist for solriamfetol?

A generic launch could occur through several paths.

At-risk launch

A manufacturer could launch after filing a Paragraph IV certification but before final resolution of patent litigation. This creates damages and injunction exposure if the patent is later upheld and found infringed.

Patent-expiration launch

A manufacturer could avoid litigation and launch after the relevant patent term expires. This is the lowest litigation-risk pathway but delays commercial entry.

Design-around launch

A generic could seek to avoid the patent by modifying:

Active loading.
Binder selection.
Lubricant selection.
Use of a disintegrant.
Tablet coating.
Dissolution rate.
Cross-pH dissolution behavior.
Tablet geometry.

The design-around route has technical limits. Solriamfetol tablets contain a high proportion of active ingredient. Significant changes to excipient levels or tablet architecture could affect hardness, friability, disintegration, dissolution, stability, or bioequivalence.

Label carve-out

The method claims list indications broader than the current Sunosi FDA indication. A generic applicant could attempt a section viii label carve-out for unprotected indications. That strategy would not necessarily avoid infringement if the ANDA product itself satisfies the formulation limitations and the remaining label encourages use within a patented indication.

How do formulation patents compare with method-of-use patents?

Formulation claims and method-of-use claims present different litigation risks.

Issue	Formulation protection	Method-of-use protection
Primary target	Product composition and performance	Prescribing or administration method
Proof required	Composition, excipients, loading, dissolution	Label, instructions, and intended use
Design-around potential	Relatively high	Depends on label language
Relevance to ANDA	Often direct	Often affected by skinny-label strategy
Key evidence	Batch records, testing, dissolution data	Proposed label and promotional materials
Main vulnerability	Claim construction and analytical testing	Induced infringement and divided-use issues

US Patent 10,512,609 combines both approaches. The treatment method is inseparable from the required tablet characteristics. That structure gives the patent more leverage against a directly substitutable product than a method claim that relies only on a broad therapeutic indication.

What manufacturing and intellectual-property barriers apply?

The principal manufacturing barrier is the tablet’s high active loading. An active content of approximately 90% to 98% leaves limited space for excipients that control flow, compression, lubrication, tablet strength, disintegration, and stability.

A manufacturer must also address:

Uniform distribution of a high-dose active ingredient.
Compression without excessive capping or friability.
Lubrication without slowing dissolution.
Consistent rapid release across production batches.
Comparable dissolution across three pH conditions.
Stability of the hydrochloride salt.
Coating performance for colored tablets.
Bioequivalence against the reference listed drug.

The pH-independent dissolution limitation may be particularly valuable in litigation. A generic can avoid one dissolution test result, but it must avoid the full claim limitation as construed, including the comparative behavior across the specified pH conditions.

How does Sunosi compare with competing narcolepsy treatments?

Sunosi competes with several drug classes, but its patent profile differs by active ingredient and dosage form.

Product or class	Active ingredient	Main commercial role	Generic or biosimilar issue
Sunosi	Solriamfetol	Wake-promoting therapy	Small-molecule ANDA
Provigil	Modafinil	Wakefulness promotion	Generic competition established
Nuvigil	Armodafinil	Wakefulness promotion	Generic competition established
Wakix	Pitolisant	Histamine H3 inverse agonist	Small-molecule patent and exclusivity risk
Xyrem/Xywav	Sodium oxybate or mixed oxybate salts	Cataplexy and excessive daytime sleepiness	Formulation, use, and device-related barriers
Traditional stimulants	Amphetamine or methylphenidate products	Wakefulness and ADHD	Mature generic markets

Solriamfetol has no biosimilar pathway because it is a chemically synthesized small molecule, not a biologic. Entry would proceed through an ANDA or, depending on the product and regulatory strategy, another abbreviated pathway.

What is the commercial exposure from US Patent 10,512,609?

The patent covers the marketed strength range of Sunosi and therefore has direct relevance to substitution economics. Exposure depends on:

Sunosi annual net sales.
The timing of the first approved ANDA.
The number of generic entrants.
Whether the first entrant receives 180-day exclusivity.
Litigation settlements.
The ability of a generic to design around the formulation claims.
Whether other Sunosi patents remain enforceable at the time of launch.

Because the claims cover all four principal tablet strengths, a successful generic product could compete across the full Sunosi dosage range rather than only one strength. The most commercially consequential claims are claims 1, 8, 11, and 13 through 16.

Key Takeaways

US Patent 10,512,609 is a formulation-linked method-of-treatment patent for solriamfetol tablets.
Its core limitations are high active loading, defined binder and lubricant ranges, rapid release, and substantially identical dissolution at pH 1.2, 4.5, and 6.8.
Claims 13 through 16 cover the 37.5 mg, 75 mg, 150 mg, and 300 mg strengths associated with Sunosi.
Claim 8 is a commercially important narrower formulation claim using hydroxypropyl cellulose and magnesium stearate.
The patent’s nominal term horizon is 2037, subject to USPTO term adjustments and other statutory factors.
Generic risk is highest for a directly substitutable tablet using the same formulation architecture and dissolution profile.
A design-around may be possible, but high active loading limits formulation flexibility.
The product is a small molecule, so biosimilar rules do not apply.
FDA Orange Book listings and Paragraph IV certifications determine the principal ANDA litigation pathway.

FAQs

Does US Patent 10,512,609 claim solriamfetol as a molecule?

No. The asserted claims focus on a method of treatment using a specified immediate-release tablet. They do not function as a broad standalone composition-of-matter claim covering every form or use of solriamfetol.

Can a generic solriamfetol tablet avoid the patent by using a different binder?

Potentially. A different binder could avoid claim 8, but it may still fall within claim 1 or claim 6 if the broader claim limitations are satisfied.

Does a fast-dissolving solriamfetol tablet necessarily infringe?

No. Fast dissolution alone is insufficient. The product must also meet the active-loading, binder, lubricant, immediate-release, and cross-pH dissolution limitations.

Are Sunosi patents eligible for biosimilar litigation?

No. Solriamfetol is a small-molecule drug. A competing product would generally use the ANDA pathway rather than the biosimilar pathway under the Public Health Service Act.

Can a generic launch after carving out narcolepsy from its label?

A label carve-out may reduce method-of-use exposure, but it does not automatically avoid formulation claims. The product’s composition and dissolution characteristics remain relevant to infringement.

References

United States Patent and Trademark Office. (2019). US Patent No. 10,512,609, pharmaceutical compositions comprising (R)-2-amino-3-phenylpropyl carbamate.
U.S. Food and Drug Administration. (2019). Sunosi prescribing information: Solriamfetol tablets, NDA 211230.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, Orange Book.
U.S. Food and Drug Administration. (n.d.). Abbreviated new drug application approvals and patent certifications.
Jazz Pharmaceuticals plc. (2023). Annual report on Form 10-K.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Axsome Malta	SUNOSI	solriamfetol hydrochloride	TABLET;ORAL	211230-001	Jun 17, 2019	AB	RX	Yes	No	10,512,609	⤷ Start Trial				TO IMPROVE WAKEFULNESS IN ADULT PATIENTS WITH EXCESSIVE DAYTIME SLEEPINESS ASSOCIATED WITH NARCOLEPSY OR OBSTRUCTIVE SLEEP APNEA (OSA)	⤷ Start Trial
Axsome Malta	SUNOSI	solriamfetol hydrochloride	TABLET;ORAL	211230-002	Jun 17, 2019	AB	RX	Yes	Yes	10,512,609	⤷ Start Trial				TO IMPROVE WAKEFULNESS IN ADULT PATIENTS WITH EXCESSIVE DAYTIME SLEEPINESS ASSOCIATED WITH NARCOLEPSY OR OBSTRUCTIVE SLEEP APNEA (OSA)	⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2017324855	⤷ Start Trial
Canada	3036068	⤷ Start Trial
Chile	2019000571	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 10,512,609

Which drugs does patent 10,512,609 protect, and when does it expire?

Summary for Patent: 10,512,609