DCT
1:18-cv-00051
Purdue Pharma LP v. Amneal Pharma LLC
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Purdue Pharma L.P. and Purdue Pharmaceuticals L.P. (Delaware)
- Defendant: Amneal Pharmaceuticals, LLC (Delaware)
- Plaintiff’s Counsel: Morris, Nichols, Arsht & Tunnell LLP; Jones Day
- Case Identification: 1:18-cv-00051, D. Del., 01/03/2018
- Venue Allegations: Venue is alleged to be proper in the District of Delaware on the basis that Defendant Amneal is a Delaware limited liability company and therefore resides in the judicial district.
- Core Dispute: Plaintiff alleges that Defendant's submission of an Abbreviated New Drug Application (ANDA) to market a generic version of the opioid analgesic OxyContin® constitutes an act of infringement of two patents covering tamper-resistant pharmaceutical formulations.
- Technical Context: The patents relate to extended-release opioid formulations designed to be physically robust, making them difficult for abusers to crush or dissolve for unintended methods of administration.
- Key Procedural History: The lawsuit was filed under the Hatch-Waxman Act, triggered by a Paragraph IV certification letter from a purported agent of the defendant. The complaint notes this is the latest in a series of lawsuits filed by Purdue against Amneal concerning the same ANDA, with prior suits targeting different patents covering the OxyContin® product.
Case Timeline
| Date | Event |
|---|---|
| 2006-08-25 | Earliest Priority Date for ’416 and ’808 Patents |
| 2011-09-27 | Original ANDA No. 203235 filed by Amneal |
| 2015-09-17 | Purdue files first related complaint against Amneal |
| 2015-10-30 | Amneal files its Amended ANDA |
| 2015-12-15 | Purdue files second related complaint against Amneal |
| 2017-03-01 | Purdue files third related complaint against Amneal |
| 2017-09-26 | U.S. Patent No. 9,770,416 Issues |
| 2017-10-03 | U.S. Patent No. 9,775,808 Issues |
| 2017-10-10 | Purdue files fourth related complaint against Amneal |
| 2017-11-21 | Date of Notice Letter regarding the ’416 and ’808 patents |
| 2018-01-03 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 9,770,416 - "TAMPER RESISTANT DOSAGE FORMS," issued September 26, 2017
The Invention Explained
- Problem Addressed: The patent addresses the widespread problem of opioid abuse, wherein abusers physically manipulate extended-release dosage forms (e.g., by crushing or dissolving) to release the full dose of the drug at once for illicit administration, such as injection or insufflation (’416 Patent, col. 2:28-45).
- The Patented Solution: The invention is a pharmaceutical tablet that is highly resistant to this type of tampering. The formulation combines an opioid active agent with a high molecular weight polyethylene oxide (PEO) which, when processed through a specific manufacturing method, results in a very hard, durable tablet (’416 Patent, col. 2:49-53). The key manufacturing step involves shaping the tablet via compression and then curing it with heated air without further compression, which causes the tablet to harden and expand, making it difficult to crush into a powder or dissolve in common solvents (’416 Patent, col. 16:37-47).
- Technical Importance: This technology represents an effort to create abuse-deterrent formulations, a significant goal in pharmaceutical development aimed at reducing the public health risks associated with prescription opioid diversion and abuse.
Key Claims at a Glance
- The complaint asserts independent claim 1 and reserves the right to assert other claims (Compl. ¶32).
- Essential elements of independent claim 1 include:
- A pharmaceutical composition with an opioid active agent and at least one high molecular weight PEO (from 1 million to 8 million MW).
- The composition is in a solid oral extended-release dosage form that is (i) compression shaped, (ii) air cured by heated air, without compression, for about 15 minutes to 8 hours at about 60-90°C, (iii) cooled, and (iv) hardened.
- The PEO is at least partially melted during curing and makes up at least 50% of the dosage form by weight.
- The dosage form expands upon curing, measured by a density decrease of at least 1.5%.
- The dosage form provides a hardness of at least 439 N.
U.S. Patent No. 9,775,808 - "TAMPER RESISTANT DOSAGE FORMS," issued October 3, 2017
The Invention Explained
- Problem Addressed: The ’808 Patent addresses the same problem as the ’416 Patent: the abuse of oral opioid dosage forms by physical and chemical tampering (’808 Patent, col. 2:28-45).
- The Patented Solution: The solution is also a tamper-resistant extended-release dosage form based on a PEO matrix. The claims of the ’808 Patent are directed to a similar manufacturing process involving thermal curing, but with different specific parameters than those recited in the ’416 Patent. The core inventive concept of creating a physically robust tablet via a heat-curing process remains central (’808 Patent, col. 2:49-56; col. 16:51-62).
- Technical Importance: Like the ’416 Patent, this technology contributes to the field of abuse-deterrent formulations by providing specific compositional and process parameters for creating crush-resistant opioid tablets.
Key Claims at a Glance
- The complaint asserts independent claim 1 and reserves the right to assert other claims (Compl. ¶39).
- Essential elements of independent claim 1 include:
- A pharmaceutical composition with an active agent comprising oxycodone, at least one high molecular weight PEO (from 1 million to 15 million MW), and at least one additive or film coating.
- The composition is in a solid oral extended-release dosage form that is (i) compression shaped, (ii) air cured by heated air, without compression, for at least 5 minutes at a temperature above the PEO's softening temperature, (iii) cooled, and (iv) hardened.
- The high molecular weight PEO comprises at least 30% of the dosage form by weight.
- The molecular weight of the PEO is based on rheological measurements.
- The total weight of the dosage form is calculated excluding film coatings.
III. The Accused Instrumentality
- Product Identification: The accused instrumentalities are "Amneal's Amended ANDA Products," which are the proposed generic versions of Purdue's OxyContin® extended-release tablets in 10, 15, 20, 30, 40, 60, and 80 mg dosage strengths (Compl. ¶1).
- Functionality and Market Context: The complaint alleges infringement based on Amneal's filing of Amended ANDA No. 203235 with the FDA (Compl. ¶31, ¶38). Under the Hatch-Waxman Act, this filing is a statutory act of infringement if the product that will be sold upon approval would infringe the patents-in-suit. The complaint alleges that Amneal's proposed generic products, if manufactured and sold, would meet the limitations of the asserted claims (Compl. ¶32, ¶39). The accused products are intended to be generic competitors to OxyContin®, a major commercial drug for the treatment of severe pain (Compl. ¶1, ¶7). Figure 40 of the asserted patents, which is attached as an exhibit to the complaint, depicts a visual comparison between a crushed reference tablet and a crushed tablet of a patented example, illustrating the latter's resistance to being reduced to a fine powder (’416 Patent, Fig. 40; Compl. ¶20, Ex. A).
IV. Analysis of Infringement Allegations
U.S. Patent No. 9,770,416 Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a pharmaceutical composition comprising: at least active agent comprising an opioid or a pharmaceutically acceptable salt, and at least one high molecular weight polyethylene oxide (PEO), having an approximate molecular weight of from 1 million to 8 million | The complaint alleges that Amneal's Amended ANDA Products are pharmaceutical compositions that contain an opioid active agent and high molecular weight PEO within the specified range. | ¶32 | col. 167:37-43 |
| wherein (a) the active agent and high molecular weight PEO are combined in a solid oral extended release dosage form that is (i) compression shaped, (ii) air cured by heated air, without compression, for a curing time of about 15 minutes to about 8 hours at a curing temperature of about 60 C to about 90 C, (iii) cooled, and (iv) hardened | The complaint alleges the Amended ANDA Products are solid oral dosage forms made by a process that includes compression shaping, air curing under the specified time and temperature conditions, cooling, and hardening. | ¶32 | col. 167:44-53 |
| (b) the high molecular weight PEO is at least partially melted upon curing and comprises at least about 50% (by weight) of the dosage form | The complaint alleges that in the Amended ANDA Products, the PEO is partially melted during curing and constitutes at least about 50% of the dosage form's weight. | ¶32 | col. 167:54-57 |
| (c) the active agent comprises at least about 1.3% (by weight) of the dosage form | The complaint alleges the active agent in the Amended ANDA Products comprises at least about 1.3% of the dosage form's weight. | ¶32 | col. 167:58-59 |
| (f) the dosage form is expanded upon curing, as measured by a decrease in density of at least about 1.5%, and the dosage form provides a hardness of at least about 439 N. | The complaint alleges the Amended ANDA Products expand upon curing, resulting in a density decrease of at least 1.5%, and have a hardness of at least 439 N. | ¶32 | col. 168:1; col. 167:64 |
U.S. Patent No. 9,775,808 Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a pharmaceutical composition comprising: at least one active agent comprising oxycodone or a pharmaceutically acceptable salt thereof; and at least one high molecular weight polyethylene oxide (PEO), having an approximate molecular weight of from 1 million to 15 million; at least one of an additive and a film coating | The complaint alleges the Amended ANDA Products are pharmaceutical compositions containing oxycodone, high molecular weight PEO, and an additive or film coating. | ¶39 | col. 159:37-44 |
| wherein (a) the active agent and high molecular weight PEO are combined in a solid oral extended release dosage form that is (i) compression shaped, (ii) air cured by heated air, without compression, for at least about 5 minutes at a temperature above the softening temperature of the high molecular weight PEO, (iii) cooled, and (iv) hardened | The complaint alleges the Amended ANDA Products are solid oral dosage forms made by a process that includes compression shaping and air curing under the specified functional time and temperature conditions. | ¶39 | col. 159:45-56 |
| (b) the high molecular weight PEO comprises at least about 30% (by weight) of the dosage form | The complaint alleges that in the Amended ANDA Products, the PEO constitutes at least about 30% of the dosage form's weight. | ¶39 | col. 159:57-59 |
- Identified Points of Contention:
- Scope Questions: The interpretation of the word "about" in relation to multiple quantitative limitations (e.g., "at least about 50%," "about 60 C," "at least about 439 N") will be a central dispute. The parties will likely contest the degree of variance permitted by this term.
- Technical Questions: A primary question will be whether the manufacturing process and final product characteristics described in Amneal's confidential ANDA filing fall within the scope of the claims. For the ’416 Patent, this raises the question of what evidence will show Amneal's product meets the specific hardness (≥439 N) and density decrease (≥1.5%) limitations. For the ’808 Patent, a key question is what constitutes "a temperature above the softening temperature of the high molecular weight PEO" and whether Amneal's process meets that functional requirement.
V. Key Claim Terms for Construction
The Term: "air cured by heated air, without compression" (’416 Patent, Claim 1)
Context and Importance: This process limitation is a cornerstone of the asserted claims. Its construction will determine whether a defendant's manufacturing process infringes, even if the final composition is similar. The dispute will likely focus on the meaning of "without compression" in the context of pharmaceutical manufacturing, where some incidental pressures may be unavoidable.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification distinguishes this step from "direct compression" used to form the tablet initially, suggesting "without compression" could mean the absence of a directed, shaping compression force during the curing step itself (’416 Patent, col. 7:55 - 8:1; col. 17:23-28).
- Evidence for a Narrower Interpretation: A defendant may argue that any pressure applied during curing, for example by tumbling tablets in a coating pan, constitutes "compression." The patent describes curing taking place in devices like a "coating pan or fluidized bed," where tablets are in motion, which could be argued to involve some form of compressive force (’416 Patent, col. 19:42-45).
The Term: "hardness of at least about 439 N" (’416 Patent, Claim 1)
Context and Importance: This is a specific, quantitative functional limitation that defines the tamper-resistance of the final product. Infringement will depend on whether the accused product meets this threshold, and the scope of "about" is critical. Practitioners may focus on this term because small variations in a generic product's measured hardness could determine the outcome of the infringement analysis.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The use of "about" implies the number is not a rigid cut-off. The specification describes a range of hardness results in its examples, which a plaintiff might use to argue for some flexibility around the 439 N value (’416 Patent, Tables 13.1-13.5).
- Evidence for a Narrower Interpretation: The patent explicitly states that 439 N is the "maximum force" of the testing apparatus used in certain examples, suggesting it could be a significant and intended threshold (’416 Patent, col. 33:55-60). A defendant could argue that "about 439 N" means a value very close to 439 N, and that the term was not intended to encompass significantly lower values.
VI. Other Allegations
- Indirect Infringement: The complaint alleges that if Amneal's ANDA is approved, its commercial activities will contribute to and induce infringement by others (e.g., patients and physicians) under 35 U.S.C. § 271(a)-(c) (Compl. ¶33, ¶40). This allegation is likely predicated on the product's labeling and instructions for use, which would direct infringing uses.
- Willful Infringement: The complaint alleges that Amneal has been aware of the patents-in-suit and has "no reasonable basis for believing" its product would not infringe, seeking a finding that the case is "exceptional" under 35 U.S.C. § 285 (Compl. ¶35, ¶42). The allegation is supported by Amneal's submission of a Paragraph IV certification, which demonstrates knowledge of the patents.
VII. Analyst’s Conclusion: Key Questions for the Case
This ANDA litigation will likely focus on the detailed technical comparison between the specifications in Amneal's confidential ANDA and the specific limitations of Purdue's patent claims. The central questions for the court appear to be:
- A core issue will be one of claim construction: How much variance does the term "about" permit for the precise quantitative limitations of the '416 patent, such as the "hardness of at least about 439 N" and the "decrease in density of at least about 1.5%"?
- A key evidentiary question will be one of process equivalence: Does the manufacturing process described in Amneal's ANDA, particularly its thermal treatment step, constitute "air cured by heated air, without compression" as that term is defined by the patents, or is there a material difference in the process that avoids infringement?
- A dispositive factual question will be one of product-by-process proof: Will the evidence show that Amneal's proposed generic product, when manufactured by the process in its ANDA, necessarily and consistently exhibits the specific chemical and physical properties required by the asserted claims?