Amneal PharmceuTicals LLC v. Almirall LLC

1. Case Identification

• Case #: IPR2018-00608
• Patent #: 9,161,926
• Filed: February 12, 2018
• Petitioner(s): Amneal Pharmaceuticals LLC and Amneal Pharmaceuticals of New York, LLC
• Patent Owner(s): Allergan, Inc.
• Challenged Claims: 1-6

2. Patent Overview

• Title: Topical Dapsone Pharmaceutical Compositions
• Brief Description: The ’926 patent discloses topical pharmaceutical compositions for treating skin conditions such as acne. The claimed compositions comprise about 7.5% w/w dapsone, a high concentration of ethoxydiglycol (30-40% w/w) as a solvent, and an acrylamide/sodium acryloyldimethyl taurate copolymer (2-6% w/w) as a polymeric viscosity builder in water, while specifically excluding the active ingredient adapalene.

3. Grounds for Unpatentability

Ground 1: Claims 1-6 are obvious over Garrett in view of Nadau-Fourcade.

• Prior Art Relied Upon: Garrett (International Publication No. WO 2009/061298) and Nadau-Fourcade (International Publication No. WO 2010/072958).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Garrett taught nearly all limitations of the challenged claims. Garrett disclosed aqueous topical compositions for treating skin conditions comprising dapsone in an overlapping range (5-10% w/w), ethoxydiglycol in an overlapping range (10-30% w/w), water, and no adapalene. While Garrett disclosed the use of generic "polymeric thickeners," it did not specifically name the claimed acrylamide copolymer. Nadau-Fourcade, which addresses stabilizing water-insoluble drugs like dapsone, remedied this by expressly teaching the claimed acrylamide copolymer (e.g., Sepineo® P 600) as one of only three groups of "preferred" gelling agents for such formulations. Petitioner asserted that the claimed concentration ranges for the copolymer (2-6%) and ethoxydiglycol (30-40%) would have been obvious results of routine optimization based on the overlapping ranges and guidance in the prior art.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Garrett and Nadau-Fourcade to create a stable and effective topical dapsone formulation. Since Garrett taught using a generic class of thickeners and Nadau-Fourcade identified the claimed acrylamide copolymer as a "preferred" option for the exact purpose of gelling a composition with a water-insoluble drug like dapsone, a POSITA would have been motivated to substitute the preferred agent from Nadau-Fourcade into Garrett’s base composition to achieve a predictable and stable result.
  • Expectation of Success: A POSITA would have had a reasonable expectation of success because the combination involved substituting one known thickening agent for another within their established functions. The components were known to be compatible, and Nadau-Fourcade's explicit preference for the claimed copolymer in similar formulations would have provided a strong assurance that the resulting composition would be stable and functional.

Ground 2: Claims 1-6 are obvious over Garrett in view of Bonacucina.

• Prior Art Relied Upon: Garrett (WO 2009/061298) and Bonacucina ("Characterization and Stability of Emulsion Gels Based on Acrylamide/Sodium Acryloyldimethyl Taurate Copolymer," AAPS PharmaSciTech, June 2009).
• Core Argument for this Ground:
  • Prior Art Mapping: As in Ground 1, Petitioner contended that Garrett disclosed the foundational dapsone composition. Bonacucina provided the specific teaching and motivation to select the claimed acrylamide copolymer over other thickeners, such as Carbopol®. The prior art Aczone® Gel 5% product used Carbopol® 980 as its thickening agent, a type of thickener also suggested in Garrett. These Carbopol®-based compositions were known to have a "gritty" texture and required neutralization with a harsh base (e.g., sodium hydroxide) to function as a thickener. Bonacucina studied the claimed copolymer (Sepineo® P 600) and described it as a "prime candidate" for topical gels that provided superior rheological properties and formed stable, uniform gels without requiring neutralization.
  • Motivation to Combine: A POSITA would combine Garrett with Bonacucina to improve the physical characteristics and manufacturing process of the dapsone gel. The known drawbacks of Carbopol® (gritty feel, required neutralization) would have motivated a formulator to seek alternatives. Bonacucina taught that the claimed acrylamide copolymer avoided these issues, rendering formulations "very pleasant for the touch and spread on the skin" and simplifying manufacturing. This made it an obvious choice to substitute into Garrett's composition to create a more cosmetically elegant and easily produced product.
  • Expectation of Success: A POSITA would have reasonably expected success in making this substitution. Bonacucina's detailed analysis confirmed the claimed copolymer's suitability and advantageous properties for topical gels. Combining this well-characterized, superior thickener with the other known and compatible ingredients from Garrett's dapsone composition would have been a predictable formulation strategy.

4. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under §325(d) would be improper. This petition represented the first time the ’926 patent had been challenged since its issuance. Crucially, the primary prior art references relied upon—Garrett, Nadau-Fourcade, and Bonacucina—were never before the examiner during the original prosecution. Petitioner asserted that the specific motivations to combine presented in the IPR were substantially different and more particular than the general obviousness rationale considered by the examiner, warranting a new review of patentability.

5. Relief Requested

• Petitioner requested the institution of an inter partes review and cancellation of claims 1-6 of the ’926 patent as unpatentable under 35 U.S.C. §103.