DCT
1:18-cv-00648
Sun Pharmaceutical Industries Ltd v. Saptalis Pharma LLC
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Sun Pharmaceutical Industries Ltd. (India) and Ranbaxy Signature, LLC (Delaware)
- Defendant: Saptalis Pharmaceuticals, LLC (Delaware)
- Plaintiff’s Counsel: Heyman Enerio Gattuso & Hirzel LLP
- Case Identification: 1:18-cv-00648, D. Del., 04/30/2018
- Venue Allegations: Venue is alleged to be proper in the District of Delaware as the Defendant is an entity organized and existing under the laws of Delaware.
- Core Dispute: Plaintiffs allege that Defendant’s filing of an Abbreviated New Drug Application (ANDA) for a generic liquid metformin hydrochloride oral solution constitutes an act of infringement of a patent covering a liquid formulation of the same drug.
- Technical Context: The lawsuit concerns pharmaceutical formulations for metformin, a widely-used drug for Type II diabetes, specifically addressing the challenges of creating a palatable liquid version for patients who cannot easily swallow large tablets.
- Key Procedural History: This action was initiated under the Hatch-Waxman Act following Defendant Saptalis's submission of ANDA No. 211309. The complaint states that the patent-in-suit is listed in the FDA's "Orange Book" for the branded drug RIOMET® and that Plaintiffs received a notice letter from Saptalis regarding its ANDA filing.
Case Timeline
| Date | Event |
|---|---|
| 2000-08-07 | U.S. Patent No. 6,890,957 Priority Date |
| 2005-05-10 | U.S. Patent No. 6,890,957 Issue Date |
| 2018-03-16 | Date of Saptalis's Notice Letter concerning its ANDA |
| 2018-04-30 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 6,890,957 - "Liquid Formulation of Metformin"
- Issued: May 10, 2005
The Invention Explained
- Problem Addressed: The patent's background section identifies that metformin hydrochloride, a common anti-diabetic agent, is typically sold as a large tablet with a "pronounced saline, bitter taste," making it difficult to swallow (col. 2:23-32). Creating a liquid alternative is challenging because conventional taste-masking agents like sugar cannot be used for diabetic patients, and other ingredients like alcohol and sodium salts are also detrimental to this patient population (col. 2:44-53).
- The Patented Solution: The invention claims to solve this problem with a specific liquid pharmaceutical composition. It combines metformin with a non-glycemic sweetener, a polyhydroxy alcohol, and a buffering system comprising a mineral acid and a bicarbonate salt to create a palatable and stable oral solution suitable for diabetics (’957 Patent, Abstract; col. 3:16-29). The formulation is designed to be "syrupy" to help mask the unpleasant taste ('957 Patent, col. 4:38-40).
- Technical Importance: This technology provided a method for delivering a widely prescribed diabetes medication in a liquid form, potentially improving compliance for pediatric patients or adults who have difficulty swallowing large solid-dose tablets ('957 Patent, col. 2:32-37).
Key Claims at a Glance
- The complaint asserts infringement of at least Claim 1 of the ’957 Patent (Compl. ¶20).
- The essential elements of independent Claim 1 are:
- A liquid pharmaceutical composition for oral administration
- comprising a therapeutically effective amount of metformin or its pharmaceutically acceptable salt
- a sweetener that does not increase the blood glucose level of a subject after ingestion thereof
- a polyhydroxy alcohol present in an amount of about 15 to about 55% by weight
- a mineral acid and bicarbonate salt both present in sufficient amounts to maintain the pH of the composition in the range of about 4.0 to about 9.0
- a pharmaceutically acceptable liquid carrier
- The complaint alleges Saptalis will induce infringement of "one or more claims" of the patent, reserving the right to assert others (Compl. ¶22).
III. The Accused Instrumentality
Product Identification
The accused instrumentality is the "Saptalis ANDA Product," a proposed generic version of RIOMET® (metformin hydrochloride) oral solution, identified in Saptalis’s ANDA No. 211309 (Compl. ¶¶1, 5).
Functionality and Market Context
The complaint alleges the Saptalis ANDA Product is a liquid pharmaceutical composition for oral administration containing metformin, designed to be a generic copy of Plaintiffs' branded product (Compl. ¶¶1, 12). Saptalis allegedly seeks FDA approval to manufacture, market, and sell this product throughout the United States (Compl. ¶5). The complaint also states that Saptalis’s ANDA contains data intended to demonstrate the bioequivalence of its product with RIOMET® (Compl. ¶16).
IV. Analysis of Infringement Allegations
No probative visual evidence provided in complaint.
Claim Chart Summary
The complaint alleges infringement of at least Claim 1. The core allegations are summarized below, based on the pleading at paragraph 20.
’957 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A liquid pharmaceutical composition for oral administration which comprises a therapeutically effective amount of metformin or its pharmaceutically acceptable salt; | The Saptalis ANDA Product is alleged to be a liquid pharmaceutical composition for oral administration containing a therapeutically effective amount of metformin. | ¶20 | col. 2:58-62 |
| a sweetener that does not increase the blood glucose level of a subject after ingestion thereof; | The Saptalis ANDA Product is alleged to contain a sweetener that does not increase blood glucose levels. | ¶20 | col. 6:5-9 |
| a polyhydroxy alcohol present in an amount of about 15 to about 55% by weight; | The Saptalis ANDA Product is alleged to contain a polyhydroxy alcohol in an amount of about 15 to about 55% by weight. | ¶20 | col. 5:47-52 |
| a mineral acid and bicarbonate salt both present in sufficient amounts to maintain the pH of the composition in the range of about 4.0 to about 9.0; | The Saptalis ANDA Product is alleged to contain a mineral acid and bicarbonate salt in amounts sufficient to maintain the pH between about 4.0 and 9.0. | ¶20 | col. 7:26-44 |
| and a pharmaceutically acceptable liquid carrier. | The Saptalis ANDA Product is alleged to contain a pharmaceutically acceptable liquid carrier. | ¶20 | col. 2:62-64 |
Identified Points of Contention
- Evidentiary Questions: The complaint is pled on "information and belief" (Compl. ¶20). A primary issue will be whether discovery confirms that the formulation described in Saptalis's ANDA contains every element recited in Claim 1.
- Scope Questions: The claim recites a percentage range for the polyhydroxy alcohol "about 15 to about 55% by weight". The interpretation of "about" and the precise percentage in the accused product may become a point of dispute.
- Technical Questions: The claim includes the functional limitation that the mineral acid and bicarbonate salt must be present in "sufficient amounts to maintain the pH" in the specified range. A question may arise as to whether the components in the accused product perform this specific buffering function, or if they are present for other formulation reasons and only incidentally affect the final pH.
V. Key Claim Terms for Construction
The Term: "maintain the pH"
- Context and Importance: This is a functional limitation tied to the presence of both a mineral acid and a bicarbonate salt. Its construction is critical because infringement requires not just the presence of these components, but that they perform the claimed function. The dispute may center on whether any resulting pH stability suffices, or if a specific buffering mechanism is required.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The plain language of the claim requires only that the components are present in amounts "sufficient" to keep the pH within the 4.0-9.0 range, which may support an interpretation covering any formulation where the presence of the acid and salt results in a pH within that range.
- Evidence for a Narrower Interpretation: The specification suggests a specific mechanism, stating it is "believed that the mineral acid and bicarbonate salts...causes in-situ formation and release of effervescent gas (carbon dioxide, which carbonation helps in the taste masking...)" (col. 8:50-55). A defendant could argue that "maintain the pH" should be construed to require this specific effervescent buffering and taste-masking action, not just passive pH control.
The Term: "a sweetener that does not increase the blood glucose level"
- Context and Importance: This limitation is core to the invention's application for diabetic patients. Practitioners may focus on this term because the eligibility of any novel or borderline sweetener used in the accused product would depend on its precise metabolic effect.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language is purely functional. This supports a broad construction covering any compound, now known or later developed, that provides sweetness without raising a subject's blood glucose.
- Evidence for a Narrower Interpretation: The specification explicitly gives examples, such as "sugar alcohol and non-nutritive sugars" (col. 6:10-11) and lists specific compounds like L-sugars, aspartame, acesulfame-K, and saccharin (col. 6:22-29). A party could argue that the term should be limited to the types of sweeteners disclosed and contemplated by the inventors at the time.
VI. Other Allegations
- Indirect Infringement: The complaint alleges that Saptalis will induce infringement by providing prescribing instructions with its ANDA product that will encourage and instruct healthcare professionals, pharmacies, and end users to perform acts of direct infringement (Compl. ¶22).
- Willful Infringement: Willfulness is alleged based on Saptalis's "actual and constructive knowledge" of the ’957 patent prior to filing its ANDA (Compl. ¶23). The complaint further alleges that the filing itself constituted an act of infringement and that Saptalis has no reasonable basis to believe its product would not infringe (Compl. ¶¶23-24). Plaintiffs also plead that the case is "exceptional" and seek attorneys' fees (Compl. ¶25).
VII. Analyst’s Conclusion: Key Questions for the Case
- A primary issue will be evidentiary confirmation: As this is an ANDA action where infringement is alleged based on the act of filing, the case will depend on whether the specific formulation detailed in Saptalis’s confidential ANDA documents contains every component, in the claimed amounts and configuration, required by Claim 1 of the ’957 patent.
- A key legal question will concern functional scope: The case may turn on whether the accused product's formulation performs the specific function of having its "pH...maintain[ed]" by the claimed acid and salt pairing. The court may need to decide if this requires the active, effervescent buffering system described in the patent’s specification or if it is met by any formulation that includes the components and falls within the claimed pH range.