Details for Patent: 5,563,175
Summary for Patent: 5,563,175
| Title: | GABA and L-glutamic acid analogs for antiseizure treatment | ||||||||||||||||||||||||||||||||||||||||||||||||
| Abstract: | A compound of the formula | ||||||||||||||||||||||||||||||||||||||||||||||||
| Inventor(s): | Richard B. Silverman, Ryszard Andruszkiewicz, Po-Wai Yuen, Denis M. Sobieray, Lloyd C. Franklin, Mark A. Schwindt | ||||||||||||||||||||||||||||||||||||||||||||||||
| Assignee: | Northwestern University , Warner Lambert Co LLC | ||||||||||||||||||||||||||||||||||||||||||||||||
| Application Number: | US08/420,575 | ||||||||||||||||||||||||||||||||||||||||||||||||
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Patent Claim Types: see list of patent claims | Use; | ||||||||||||||||||||||||||||||||||||||||||||||||
| Patent landscape, scope, and claims: | US Patent 5,563,175: Scope, Claims, Expiration, and Pregabalin Patent LandscapeUS Patent No. 5,563,175 covers the use of substantially pure S-(+)-4-amino-3-(2-methylpropyl)butanoic acid, now known as pregabalin, to treat seizure disorders. The patent is a narrow method-of-use patent: it does not claim pregabalin as a chemical compound, a pharmaceutical composition, a dosage regimen, or a manufacturing process. The patent issued on October 8, 1996. Its listed term was extended through December 30, 2018, under the Hatch-Waxman patent-term-extension provisions. A six-month pediatric exclusivity period extended associated regulatory protection to June 30, 2019. The patent is now expired and does not create a current US barrier to generic pregabalin for seizure disorders. What does US Patent 5,563,175 claim?The patent contains a single substantive claim:
The claim has four principal limitations:
The claimed molecule is pregabalin, also known as (S)-3-(aminomethyl)-5-methylhexanoic acid. Its common identifiers include CAS Registry Number 148553-50-8 and the brand name Lyrica. How broad is the scope of the US 5,563,175 claim?The claim is broad in therapeutic scope but limited in subject matter. It does not specify:
The absence of a dose limitation gives the claim substantial breadth during its term. A product administered in a capsule, tablet, oral solution, or another delivery form could potentially fall within the claim if the active ingredient is substantially pure S-(+)-pregabalin and the patient has a seizure disorder. The claim does not require that pregabalin be the only active pharmaceutical ingredient. A combination product could implicate the claim if it administers an effective amount of the claimed compound to a patient with a seizure disorder. Does US Patent 5,563,175 claim pregabalin itself?No. The patent does not contain a product claim to pregabalin as a chemical compound. This distinction affected generic litigation and regulatory strategy. A party could not infringe the patent merely by making or selling pregabalin outside the claimed treatment context. Infringement required the method elements, including treatment of a patient with a seizure disorder. The patent also does not independently claim:
The stereochemical limitation is central. The claim is directed to the S-(+) enantiomer, which is the active ingredient in Lyrica. A product containing only the R enantiomer would not satisfy the literal compound limitation, although a racemate would raise separate questions concerning whether it contains a substantially pure amount of the S enantiomer and whether other patent claims apply. What was the patent term and expiration date?
The December 30, 2018 date is the commercially relevant patent expiration date associated with the Lyrica regulatory estate. The six-month pediatric exclusivity period did not extend the patent term itself. It delayed certain abbreviated regulatory approvals and commercial launches until June 30, 2019. The patent cannot now support a new US infringement action based on conduct occurring after expiration. Historical infringement claims, if otherwise viable, are governed by applicable limitation periods and litigation-specific facts. What was the Orange Book status of US 5,563,175?US 5,563,175 was listed in the FDA Orange Book for Lyrica and was associated with a method-of-use indication involving epilepsy or seizure disorders. An Orange Book listing does not prove that every product or use infringes. It identifies a patent that the reference-product sponsor represented as relevant to an approved use or drug product. For a method-of-use patent, the listing generally relates to the approved indication rather than to every possible use of the active ingredient. The practical consequences were significant during the term:
Because the patent expired in 2018 and pediatric exclusivity ended in 2019, it no longer creates an Orange Book-based approval barrier for current generic applications. How did Paragraph IV challenges affect pregabalin generic entry?Pregabalin generic applicants used the Hatch-Waxman framework to challenge Lyrica-related patents. The central issues included:
For a method claim such as the claim in US 5,563,175, the principal infringement theory would have been induced infringement under 35 U.S.C. § 271(b), based on the generic label, marketing materials, or other conduct encouraging treatment of seizure disorders. A generic applicant could reduce risk by using a skinny label that omitted the patented seizure indication. That strategy depends on FDA approval, the exact Orange Book use code, the remaining unpatented indications, and the content of the proposed labeling. A label carve-out does not eliminate all potential induced-infringement risk if other evidence shows an intent to encourage the patented use. Which patent families protected Lyrica beyond US 5,563,175?The commercial Lyrica estate included multiple patent categories. US 5,563,175 was only one component.
The most commercially important Lyrica patents included US 5,563,175 and later patents directed to pregabalin uses, including pain-related indications. The precise scope of each later patent depended on its claims, Orange Book use code, expiration date, and any patent-term adjustment or extension. A freedom-to-operate analysis limited to US 5,563,175 would therefore be incomplete for activity during the 2000s and 2010s. It is adequate for determining whether this specific patent currently blocks generic seizure-disorder use: it does not. What formulations were protected by the Lyrica patent estate?US 5,563,175 does not claim a formulation. It covers administration of substantially pure pregabalin in an effective amount. Lyrica was commercially supplied primarily as immediate-release oral capsules and an oral solution. Formulation or dosage-form patents, if applicable to a particular product or period, would have to be analyzed separately. A generic capsule containing pregabalin did not infringe US 5,563,175 merely because it had the same general dosage form as Lyrica. The relevant question under this patent was whether the product and associated conduct satisfied the seizure-treatment method claim. Formulation design could still matter under other patents, including claims directed to:
What companies challenged the Lyrica patent estate?Multiple generic manufacturers pursued US pregabalin approvals after filing Paragraph IV certifications against Lyrica-related patents. Publicly reported generic participants included Teva, Mylan, Dr. Reddy's Laboratories, Sandoz and other ANDA sponsors. The litigation was not limited to US 5,563,175. It involved the broader Lyrica patent portfolio, including indication-specific patents and related Orange Book listings. Settlements and other case resolutions controlled the timing and scope of individual generic launches. Generic pregabalin products began entering the US market in 2019 after the principal patent and pediatric-exclusivity barriers ended. The commercial launch timing varied by manufacturer, dosage form, indication strategy and settlement position. What settlement agreements affected pregabalin generic launch?Lyrica-related settlements generally had to be assessed patent by patent and defendant by defendant. The commercial effect of a settlement could include:
A settlement involving a later pain-use patent would not necessarily determine the legal status of the seizure-disorder method claim in US 5,563,175. The claims, patents and licensed activities must be matched individually. Is there biosimilar risk for pregabalin?No. Pregabalin is a synthetic small-molecule drug, not a biologic. It is regulated through the generic-drug pathway under section 505(j) of the Federal Food, Drug, and Cosmetic Act, not through the biosimilar pathway under section 351(k) of the Public Health Service Act. The relevant competitive risks are:
How strong was the patent position of US 5,563,175?During its term, the patent had meaningful commercial value because it covered treatment of seizure disorders with the single active pregabalin enantiomer and did not include a dose, route or formulation limitation. Its principal weaknesses were structural:
The patent was therefore stronger against labeled sale for epilepsy than against off-label or non-seizure use, unbranded bulk manufacture, or generic products marketed with a valid carve-out. What is the current competitive and revenue impact?The current direct revenue exposure from US 5,563,175 is zero as a blocking right because the patent has expired. The commercial impact is historical: the patent helped protect Pfizer's Lyrica franchise during the period when pregabalin was used for epilepsy and before broad generic entry. After generic entry, pregabalin experienced conventional small-molecule price erosion. Competition came from multiple ANDA-approved products rather than biosimilars. Pfizer's remaining exposure depended on the indication, product presentation and the status of other Lyrica-related patents, not on US 5,563,175 alone. What geographic coverage does US 5,563,175 provide?The patent provides rights only in the United States. It does not establish protection in:
Foreign patent families must be reviewed separately. Expiration dates, patent-term adjustments, supplementary protection certificates, pediatric extensions and litigation outcomes can differ by country. What manufacturing and IP barriers remain?US 5,563,175 creates no current manufacturing barrier because it is expired and does not claim a manufacturing process. Commercial entry can still require compliance with:
The key distinction is between regulatory and intellectual-property barriers. A manufacturer may need to establish a reliable source of substantially pure pregabalin, but that requirement is not itself a continuing monopoly under US 5,563,175. Key Takeaways
FAQsCan a generic manufacturer sell pregabalin for epilepsy today?Yes. US 5,563,175 is expired, and the related pediatric exclusivity period ended June 30, 2019. Other unexpired patents would need separate review. Does US 5,563,175 cover the R enantiomer of pregabalin?No. The claim specifically recites the S-(+) compound. The R enantiomer is outside the literal compound limitation. Does importing pregabalin into the United States infringe this patent?Not currently, because the patent is expired. During its term, importation alone would not necessarily satisfy the method claim without evidence tied to administration or induced infringement. Could the patent be asserted against a manufacturer selling pregabalin for pain?During its term, the seizure-disorder claim would require the seizure-treatment elements. Pain indications were generally addressed through separate method-of-use patents and Orange Book listings. Is US 5,563,175 a composition-of-matter patent?No. It is a method-of-treatment patent. The claim covers administering substantially pure S-(+)-pregabalin to a patient with a seizure disorder. References
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Drugs Protected by US Patent 5,563,175
| Applicant | Tradename | Generic Name | Dosage | NDA | Approval Date | TE | Type | RLD | RS | Patent No. | Patent Expiration | Product | Substance | Delist Req. | Patented / Exclusive Use | Submissiondate |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| >Applicant | >Tradename | >Generic Name | >Dosage | >NDA | >Approval Date | >TE | >Type | >RLD | >RS | >Patent No. | >Patent Expiration | >Product | >Substance | >Delist Req. | >Patented / Exclusive Use | >Submissiondate |
International Family Members for US Patent 5,563,175
| Country | Patent Number | Estimated Expiration | Supplementary Protection Certificate | SPC Country | SPC Expiration |
|---|---|---|---|---|---|
| European Patent Office | 0641330 | ⤷ Start Trial | 91112 | Luxembourg | ⤷ Start Trial |
| European Patent Office | 0641330 | ⤷ Start Trial | 300164 | Netherlands | ⤷ Start Trial |
| European Patent Office | 0641330 | ⤷ Start Trial | SPC/GB04/034 | United Kingdom | ⤷ Start Trial |
| European Patent Office | 0641330 | ⤷ Start Trial | CA 2004 00036 | Denmark | ⤷ Start Trial |
| >Country | >Patent Number | >Estimated Expiration | >Supplementary Protection Certificate | >SPC Country | >SPC Expiration |
