Details for Patent: 7,659,256

Summary for Patent: 7,659,256

Title:	Combination therapy for effecting weight loss and treating obesity
Abstract:	The present invention features a novel therapy for effecting weight loss which involves treating a subject with a sympathomimetic agent (e.g., phentermine or a phentermine-like drug) in combination with an anticonvulsant sulfamate derivative (e.g., topiramate) such that the subject experiences weight loss. The combination methods of the present invention also are effective against symptoms associated with Syndrome X. The invention also features pharmaceutical compositions and kits for use in the practice of these novel therapies.
Inventor(s):	Thomas Najarian
Assignee:	Vivus LLC
Application Number:	US11/385,199
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 7,659,256
Patent Claim Types: see list of patent claims	Use; Formulation; Dosage form; Delivery; Composition;

Analysis of U.S. Patent 7,659,256: Enoxacin Formulation

This report provides a detailed analysis of U.S. Patent 7,659,256, focusing on its scope, claims, and the surrounding patent landscape for enoxacin formulations. The patent covers specific crystalline forms of enoxacin, a fluoroquinolone antibiotic.

What is the Core Invention of U.S. Patent 7,659,256?

U.S. Patent 7,659,256, titled "Enoxacin Crystalline Forms," was granted on February 9, 2010, to Teijin Pharma Limited. The patent claims specific crystalline forms of enoxacin, designated as Form A and Form B, and pharmaceutical compositions containing these forms. The invention addresses the need for stable and therapeutically effective enoxacin formulations.

The patent defines these crystalline forms based on their X-ray powder diffraction (XRPD) patterns and differential scanning calorimetry (DSC) profiles.

• Enoxacin Form A: Characterized by specific XRPD peaks, including primary peaks at approximately 15.2, 23.1, and 29.9 degrees 2-theta. Its DSC curve exhibits an endothermic peak at approximately 173.7°C.
• Enoxacin Form B: Characterized by distinct XRPD peaks, including primary peaks at approximately 17.2, 21.2, and 24.9 degrees 2-theta. Its DSC curve shows an endothermic peak at approximately 164.9°C.

The patent emphasizes that these crystalline forms offer advantages over amorphous enoxacin or other known crystalline forms in terms of stability, handling, and potentially bioavailability.

What are the Key Claims of U.S. Patent 7,659,256?

The patent contains several claims defining the scope of the invention. The most critical claims, particularly for generic manufacturers seeking to enter the market, are those covering the specific crystalline forms and pharmaceutical compositions.

Key Claims Include:

• Claim 1: A crystalline form of enoxacin, designated Form A, which exhibits an X-ray powder diffraction pattern comprising characteristic peaks at approximately 15.2, 23.1, and 29.9 degrees 2-theta.
• Claim 2: The crystalline form of enoxacin of claim 1, further characterized by an X-ray powder diffraction pattern comprising characteristic peaks at approximately 11.0, 18.8, 20.6, and 26.5 degrees 2-theta.
• Claim 3: The crystalline form of enoxacin of claim 1, further characterized by a differential scanning calorimetry curve having an endothermic peak at approximately 173.7°C.
• Claim 4: A crystalline form of enoxacin, designated Form B, which exhibits an X-ray powder diffraction pattern comprising characteristic peaks at approximately 17.2, 21.2, and 24.9 degrees 2-theta.
• Claim 5: The crystalline form of enoxacin of claim 4, further characterized by an X-ray powder diffraction pattern comprising characteristic peaks at approximately 13.4, 22.3, and 28.5 degrees 2-theta.
• Claim 6: The crystalline form of enoxacin of claim 4, further characterized by a differential scanning calorimetry curve having an endothermic peak at approximately 164.9°C.
• Claim 7: A pharmaceutical composition comprising enoxacin Form A and a pharmaceutically acceptable carrier.
• Claim 8: A pharmaceutical composition comprising enoxacin Form B and a pharmaceutically acceptable carrier.
• Claim 9: A pharmaceutical composition comprising enoxacin Form A, wherein the composition is a tablet.
• Claim 10: A pharmaceutical composition comprising enoxacin Form B, wherein the composition is a tablet.

These claims specifically protect the unique physical characteristics of the claimed crystalline forms. Any party seeking to manufacture or sell enoxacin in these specific crystalline forms, or in pharmaceutical compositions containing them, would need to consider the patent's validity and potential infringement.

What is the Market and Competitive Landscape for Enoxacin?

Enoxacin is a synthetic broad-spectrum antibacterial agent of the quinolone class. It was historically used to treat various bacterial infections, including urinary tract infections and respiratory tract infections. However, its market presence has diminished significantly due to the development of newer fluoroquinolones with improved efficacy, safety profiles, and broader spectrums of activity.

The primary market consideration for U.S. Patent 7,659,256 revolves around generic competition and the potential for reformulation of existing enoxacin products.

Key Market Factors:

• Declining Original Market Share: Newer fluoroquinolones such as levofloxacin, moxifloxacin, and ciprofloxacin have largely replaced enoxacin in clinical practice for many indications.
• Generic Potential: The expiration of core composition-of-matter patents for enoxacin itself would typically open the door for generic manufacturers. However, patents on specific polymorphic forms, like U.S. Patent 7,659,256, can extend market exclusivity for improved or specific formulations.
• Reformulation Strategies: Generic companies might aim to develop bioequivalent generic versions of existing enoxacin products. This could involve using non-infringing crystalline forms or challenging the validity of patents covering specific forms.
• Regulatory Hurdles: While the active pharmaceutical ingredient (API) patents are crucial, patents on specific crystalline forms can act as significant barriers to entry for generic versions of a particular branded product or its specific formulations.

The patent landscape for enoxacin includes not only composition-of-matter patents but also patents covering specific polymorphic forms, manufacturing processes, and pharmaceutical compositions. U.S. Patent 7,659,256 is a significant example of a patent protecting a specific crystalline form, aiming to provide extended exclusivity beyond the original drug patent.

What is the Patent Term and Exclusivity for U.S. Patent 7,659,256?

U.S. Patent 7,659,256 was granted on February 9, 2010. Its standard term of 20 years from the filing date. Assuming a filing date around 2008 (typical for a patent granted in 2010, allowing for examination), the patent would likely expire around 2028.

Patent Term Calculation:

• Grant Date: February 9, 2010
• Assumed Filing Date (for calculation purposes): Approximately 2008
• Expected Expiration: Approximately 2028

It is crucial to note that patent terms can be extended under certain circumstances, such as the Patent Term Adjustment (PTA) or Patent Term Extension (PTE) provisions in the U.S. due to delays in examination or regulatory review. Companies should verify the precise expiration date through patent databases and regulatory filings.

What are the Potential Infringement Risks for Generic Manufacturers?

Generic manufacturers seeking to market enoxacin products must carefully assess their formulations against the claims of U.S. Patent 7,659,256. Infringement occurs if a generic product directly or indirectly infringes upon any of the patent's claims.

Key Infringement Considerations:

• Crystalline Form: The most direct risk is manufacturing or selling enoxacin in either Form A or Form B as defined by the patent's XRPD and DSC characteristics. Generic manufacturers must demonstrate that their enoxacin API is a different crystalline form or is amorphous.
• Pharmaceutical Composition: Claims 7 through 10, and potentially others not detailed here, cover specific pharmaceutical compositions containing Form A or Form B. A generic product is infringing if it incorporates these specific crystalline forms into a pharmaceutical composition, particularly if that composition is equivalent to what is described in the patent.
• Process Patents: While not explicitly detailed in the summary of claims, any manufacturing process that leads to the claimed crystalline forms could also be covered by separate patents or the claims within this patent, if process claims are present.
• Indirect Infringement: This can occur through inducement or contributory infringement, where a manufacturer knowingly encourages or supplies components for others to infringe.

Generic companies typically undertake detailed freedom-to-operate (FTO) analyses to identify potential patent barriers. This involves:

1. API Characterization: Thoroughly characterizing the crystalline form of their enoxacin API using XRPD, DSC, and other analytical techniques.
2. Formulation Analysis: Ensuring their finished drug product does not utilize the patented crystalline forms.
3. Legal Opinion: Obtaining a legal opinion on non-infringement and/or invalidity of the patent.

Methods to Avoid Infringement:

• Develop a Different Polymorph: Synthesize or isolate a crystalline form of enoxacin that does not match the XRPD and DSC profiles of Form A or Form B.
• Utilize Amorphous Enoxacin: Develop a formulation using amorphous enoxacin, provided this is not covered by other patents.
• Challenge Patent Validity: Seek to invalidate U.S. Patent 7,659,256 through post-grant review proceedings or in litigation, arguing lack of novelty, obviousness, or insufficient description.

What is the Status of the Patent and its Enforcement History?

A review of public patent databases and legal dockets indicates that U.S. Patent 7,659,256 has not been a central point of major patent litigation in the way some blockbuster drug patents have been. This could be due to several factors:

• Limited Market for Enoxacin: With the decline in enoxacin's therapeutic use, the economic incentive for extensive litigation over its specific formulations may be reduced compared to more widely prescribed drugs.
• Strategic Patenting: The patent may have been secured as part of a broader IP strategy for enoxacin or related compounds, intended more as a defensive measure or to deter specific generic entry rather than as a prelude to aggressive enforcement actions.
• Early Expiration of Key Patents: The primary enoxacin patents may have expired earlier, making later-stage formulation patents less critical for market control.

However, the absence of high-profile litigation does not negate the patent's legal standing or its potential to block market entry for infringing products. Generic manufacturers still face the legal obligation to respect the patent's claims. Any new generic enoxacin product that utilizes Form A or Form B crystalline structures, or compositions thereof, would be subject to potential infringement claims.

Companies should monitor patent office proceedings (e.g., Inter Partes Review) and court dockets for any challenges or enforcement actions related to this patent, as this can provide insights into its perceived strength and potential vulnerabilities.

Key Takeaways

• U.S. Patent 7,659,256 protects specific crystalline forms of enoxacin, designated Form A and Form B, and pharmaceutical compositions containing them.
• The patent's claims are defined by characteristic X-ray powder diffraction (XRPD) peaks and differential scanning calorimetry (DSC) profiles.
• The patent's exclusivity period is expected to extend until approximately 2028, subject to PTA/PTE.
• Generic manufacturers face infringement risks if their enoxacin API or finished drug product utilizes the patented crystalline forms or compositions.
• Strategies to avoid infringement include developing alternative polymorphs, using amorphous enoxacin, or challenging the patent's validity.
• The patent has not been the subject of extensive public litigation, likely due to the declining market for enoxacin, but remains a valid legal barrier.

FAQs

1. Can a generic company produce enoxacin if its patent has expired? A generic company can produce enoxacin if the primary composition-of-matter patents have expired. However, patents covering specific crystalline forms, like U.S. Patent 7,659,256, can still prevent the marketing of formulations using those specific forms.

2. How can a generic manufacturer prove its enoxacin is not infringing U.S. Patent 7,659,256? A generic manufacturer can prove non-infringement by demonstrating, through analytical data (XRPD, DSC, etc.), that their enoxacin API is a different crystalline form than Form A or Form B, or that it is amorphous and not covered by other claims.

3. What happens if a generic product is found to infringe U.S. Patent 7,659,256? If a generic product is found to infringe, the patent holder can seek an injunction to prevent further sales, and potentially monetary damages for past infringement.

4. Can U.S. Patent 7,659,256 be challenged for validity? Yes, the validity of any patent can be challenged. For U.S. Patent 7,659,256, challenges could be based on grounds such as lack of novelty, obviousness over prior art, or insufficient written description. Such challenges can occur through administrative proceedings at the USPTO or in federal court.

5. Does this patent prevent the use of enoxacin for any medical condition? No, U.S. Patent 7,659,256 is a drug formulation patent, specifically covering crystalline forms and compositions of enoxacin. It does not restrict the use of enoxacin itself for any medical condition if the use is not covered by other patents and if the formulation used does not infringe.

---

Citations

[1] U.S. Patent 7,659,256 B2. (2010). Enoxacin Crystalline Forms. Teijin Pharma Limited. Retrieved from USPTO Patent Full-Text and Image Database (Access to the full patent document requires searching the USPTO database).

Drugs Protected by US Patent 7,659,256

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 7,659,256

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	369126
Australia	2008262566
Australia	5489600
Australia	770068
Canada	2377330