DCT

1:18-cv-01673

Anacor Pharma Inc v. Ascent Pharma Inc

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I. Executive Summary and Procedural Information

Case Timeline

Date Event
2005-02-16 Earliest Priority Date for all Patents-in-Suit
2017-01-24 U.S. Patent No. 9,459,938 Issued
2017-02-14 U.S. Patent No. 9,566,289 Issued
2017-02-14 U.S. Patent No. 9,566,290 Issued
2017-02-21 U.S. Patent No. 9,572,823 Issued
2018-09-12 Defendants begin sending ANDA Notice Letters
2018-10-25 Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 9,459,938 - "Boron-Containing Small Molecules"

  • Patent Identification: U.S. Patent No. 9,459,938, "Boron-Containing Small Molecules," Issued January 24, 2017.
  • The Invention Explained:
    • Problem Addressed: The patent describes the significant challenges in treating fungal infections of the nail (onychomycosis), noting that topical treatments often fail due to poor penetration of the nail plate, while systemic oral therapies can have significant adverse side effects, including liver toxicity (’289 Patent, col. 1:42-2:20).
    • The Patented Solution: The invention is a method for treating these infections by topically applying a specific boron-containing small molecule, 1,3-dihydro-5-fluoro-1-hydroxy-2,1-benzoxaborole (tavaborole), in a 5% solution. This molecule is described as having physicochemical properties that facilitate penetration of the nail plate to reach the site of infection in the nail bed (’289 Patent, col. 132:50-59; Abstract).
    • Technical Importance: This approach provides a topical treatment for onychomycosis that is designed to be effective enough to penetrate the nail while avoiding the systemic side effects associated with oral antifungal medications (’289 Patent, col. 2:10-20).
  • Key Claims at a Glance:
    • The complaint asserts dependent claims 3, 5, and 6, which rely on independent claim 1 (Compl. ¶173).
    • The essential elements of independent claim 1 are:
      • A method of treating a Tinea unguium infection of a toenail of a human
      • comprising topically administering to the toenail
      • a pharmaceutical composition comprising 1,3-dihydro-5-fluoro-1-hydroxy-2,1-benzoxaborole or a pharmaceutically acceptable salt thereof
      • in an amount sufficient to treat the infection
      • wherein the pharmaceutical composition is in the form of a solution comprising 5% w/w 1,3-dihydro-5-fluoro-1-hydroxy-2,1-benzoxaborole.

U.S. Patent No. 9,566,289 - "Boron-Containing Small Molecules"

  • Patent Identification: U.S. Patent No. 9,566,289, "Boron-Containing Small Molecules," Issued February 14, 2017.
  • The Invention Explained:
    • Problem Addressed: The patent addresses the same technical problem of effectively delivering an antifungal agent through the dense keratin of the nail plate to treat onychomycosis (’289 Patent, col. 1:42-2:20).
    • The Patented Solution: Rather than a method of treatment, this patent claims a specific pharmaceutical formulation (a composition of matter) designed for topical application. The formulation combines the active ingredient, tavaborole, with a specific solvent system (propylene glycol and ethanol) and a chelating agent (EDTA) to create a stable and effective topical solution (’289 Patent, col. 170:20-30; Abstract).
    • Technical Importance: The claimed formulation represents a specific solution to the drug delivery problem by providing a vehicle for the tavaborole active ingredient that enables its penetration of the nail plate.
  • Key Claims at a Glance:
    • The complaint asserts claims 10 and 12-15 (Compl. ¶173). These claims depend on independent claim 4.
    • The essential elements of independent claim 4 are:
      • A pharmaceutical formulation
      • comprising about 5% w/w 1,3-dihydro-5-fluoro-1-hydroxy-2,1-benzoxaborole, or a pharmaceutically acceptable salt thereof
      • propylene glycol
      • ethanol
      • and ethylene diamine tetraacetic acid (EDTA) or a pharmaceutically acceptable salt thereof.
    • The complaint reserves the right to assert additional claims (Compl. ¶173, ¶178).

U.S. Patent No. 9,566,290 - "Boron-Containing Small Molecules"

  • Patent Identification: U.S. Patent No. 9,566,290, "Boron-Containing Small Molecules," Issued February 14, 2017.
  • Technology Synopsis: This patent claims a method of treating onychomycosis by administering a composition containing tavaborole. The claims specify the biological mechanism of action, stating the amount of the compound is "effective to inhibit an aminoacyl tRNA synthetase," and more specifically, "leucyl tRNA synthetase," in the target fungus (Compl. ¶¶159-160).
  • Asserted Claims: Independent claim 1 and dependent claims 2, 5-6, 8, and 11-12 (Compl. ¶173).
  • Accused Features: The defendants' proposed generic tavaborole product is accused of infringing because it contains the same active ingredient that allegedly treats onychomycosis via the same claimed biological mechanism (Compl. ¶178).

U.S. Patent No. 9,572,823 - "Boron-Containing Small Molecules"

  • Patent Identification: U.S. Patent No. 9,572,823, "Boron-Containing Small Molecules," Issued February 21, 2017.
  • Technology Synopsis: This patent claims a method of delivering the tavaborole compound to the nail bed to treat onychomycosis. The method involves contacting the "dorsal layer of the nail plate" with a composition containing the compound, which then "penetrates the nail plate" to treat the infection (Compl. ¶166). The claims focus on the specific pathway of drug delivery.
  • Asserted Claims: Independent claim 1 and dependent claim 2 (Compl. ¶173).
  • Accused Features: The defendants' proposed generic tavaborole solution is accused of infringing because its intended use involves the same claimed method of delivery through the nail plate to the nail bed (Compl. ¶178).

III. The Accused Instrumentality

  • Product Identification: The accused instrumentalities are the generic tavaborole topical solution, 5% products for which each Defendant has filed an ANDA with the FDA (Compl. ¶1, ¶11). The act of infringement under the Hatch-Waxman Act is the filing of the ANDA itself (Compl. ¶176).
  • Functionality and Market Context: The "Defendants' ANDA Products" are intended to be generic bioequivalents to Anacor's branded drug, Kerydin® (Compl. ¶12). They are topical solutions containing 5% tavaborole as the active pharmaceutical ingredient and are intended for the treatment of onychomycosis of the toenails (Compl. ¶1, ¶12). As generic drugs, they are designed to be therapeutic substitutes for the branded product and will be marketed for the same FDA-approved indication upon approval (Compl. ¶171).
    No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

U.S. Patent No. 9,459,938 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A method of treating a Tinea unguium infection of a toenail of a human... The Defendants' proposed product labeling will direct the treatment of onychomycosis (a Tinea unguium infection) of the toenail in humans. ¶179 col. 322:25-27
...the method comprising topically administering to the toenail... The ANDA Products are topical solutions, and the proposed labeling will instruct patients to apply the solution to the affected toenail. ¶179 col. 322:28-29
...a pharmaceutical composition comprising 1,3-dihydro-5-fluoro-1-hydroxy-2,1-benzoxaborole... The ANDA Products are alleged to contain 1,3-dihydro-5-fluoro-1-hydroxy-2,1-benzoxaborole (tavaborole) as the active ingredient. ¶12 col. 322:29-32
...wherein the pharmaceutical composition is in the form of a solution comprising 5% w/w 1,3-dihydro-5-fluoro-1-hydroxy-2,1-benzoxaborole. The Defendants' ANDA submissions seek approval for a 5% w/w topical solution of tavaborole. ¶1 col. 322:33-36

U.S. Patent No. 9,566,289 Infringement Allegations

Claim Element (from Independent Claim 4) Alleged Infringing Functionality Complaint Citation Patent Citation
A pharmaceutical formulation, comprising about 5% w/w 1,3-dihydro-5-fluoro-1-hydroxy-2,1-benzoxaborole, or a pharmaceutically acceptable salt thereof... The ANDA Products are formulated to contain approximately 5% w/w of tavaborole. ¶1 col. 324:11-14
...propylene glycol, ethanol, and ethylene diamine tetraacetic acid (EDTA) or a pharmaceutically acceptable salt thereof. The ANDA Products are alleged to contain the same or equivalent ingredients as Kerydin®, which includes these specified excipients. ¶12 col. 324:15-17

Identified Points of Contention

  • Compositional Scope: For the ’289 Patent, a central issue may be whether the defendants' generic formulations are exact copies. The complaint alleges the ANDA products contain the "same or equivalent ingredients" (Compl. ¶12), but the infringement analysis will depend on whether the proposed generic formulations literally contain propylene glycol, ethanol, and EDTA as recited in claim 4. Any deviation in the excipients could be a basis for a non-infringement argument.
  • Label-Induced Infringement: For the method claims of the ’938, ’290, and ’823 patents, infringement will turn on the specific instructions included in the defendants' proposed product labeling. The analysis will question whether the label will necessarily direct physicians and patients to perform every step of the claimed methods, including treating the specific fungal species or achieving nail penetration as claimed.

V. Key Claim Terms for Construction

  • The Term: "about 5% w/w" (’289 Patent, Claim 4)

    • Context and Importance: This term defines the concentration of the active ingredient, tavaborole. The scope of "about" will be critical. A narrow interpretation could allow a defendant to design around the claim with a formulation that is bioequivalent but falls just outside the construed range, while a broader interpretation would cover minor manufacturing variances and intentional slight deviations.
    • Intrinsic Evidence for a Broader Interpretation: The patent specification discloses exemplary formulations with concentrations ranging from 1% to 15% w/w, suggesting the inventors contemplated a wider range than exactly 5.0% (’289 Patent, col. 166:10-15).
    • Intrinsic Evidence for a Narrower Interpretation: The commercial embodiment of the invention (Kerydin®) is a 5% solution, and specific examples in the patent focus on this concentration. A party may argue that "about 5%" should be construed narrowly around this successfully tested and approved embodiment (’289 Patent, col. 172:49-55).

  • The Term: "a solvent system" (’289 Patent, Claim 1)

    • Context and Importance: Independent claim 1 introduces "a solvent system," while dependent claim 4 recites specific components "propylene glycol" and "ethanol." The interpretation will determine whether the "solvent system" in the asserted claims is limited to only these two components or could include others. Practitioners may focus on this term if any defendant's formulation includes additional solvents.
    • Intrinsic Evidence for a Broader Interpretation: The term "comprising" in claim 4 is presumptively open-ended. Further, the detailed description provides a long list of suitable solvents and co-solvents for topical formulations, beyond just ethanol and propylene glycol, suggesting the inventors did not intend to limit the invention to a two-component system (’289 Patent, col. 170:56-171:34).
    • Intrinsic Evidence for a Narrower Interpretation: A defendant may argue that in the context of claim 4, the explicit recitation of "propylene glycol, ethanol" defines the entirety of the solvent system for that specific embodiment, and that the patentee chose to claim this specific combination to distinguish it from the prior art.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges active inducement of infringement against all defendants. The basis for this allegation is that the defendants' proposed product labeling will instruct physicians to prescribe and patients to use the generic products in a manner that directly infringes Anacor's method claims. The complaint alleges defendants know and intend this outcome (Compl. ¶¶180, 199).
  • Willful Infringement: Willfulness is alleged based on defendants having "full knowledge of the patents-in-suit" and proceeding with their ANDA filings "without a reasonable basis for believing that it would not be liable for infringement" (Compl. ¶¶184, 203). This knowledge is predicated on the patents being listed in the FDA's Orange Book and the defendants' requisite review of those patents prior to filing their Paragraph IV certifications.

VII. Analyst’s Conclusion: Key Questions for the Case

  • A primary issue will be one of compositional equivalence: Will discovery confirm that the defendants' proposed generic drug formulations are identical copies of the branded Kerydin® product, containing not only the tavaborole active ingredient but also the specific combination of excipients (propylene glycol, ethanol, EDTA) recited in the ’289 patent's composition claims? Any variation could create a viable non-infringement defense.
  • The central legal dispute will likely be one of patent validity: In Hatch-Waxman litigation where the generic product is a copy of the branded drug, infringement is often a secondary issue. The case will likely turn on whether the defendants can prove by clear and convincing evidence that Anacor's claims—covering a specific concentration, formulation, and method of use—are invalid as obvious in light of prior art related to topical antifungal compounds and nail penetration formulations.