DCT

3:18-cv-16012

Kythera Biopharma Inc v. Slayback Pharma LLC

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Key Events
Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 3:18-cv-16012, D.N.J., 11/09/2018
  • Venue Allegations: Plaintiff alleges venue is proper in the District of New Jersey because Defendant has a regular and established place of business in the district and committed acts of infringement there, including preparing and submitting its Abbreviated New Drug Application (ANDA).
  • Core Dispute: Plaintiff alleges that Defendant’s filing of an ANDA to market a generic version of Plaintiff's Kybella® injectable drug constitutes an act of infringement of three patents related to stabilized formulations of deoxycholic acid.
  • Technical Context: The technology concerns aqueous pharmaceutical formulations of deoxycholic acid used for non-surgical reduction of localized fat deposits, such as submental (under-chin) fat.
  • Key Procedural History: The lawsuit was triggered by Defendant’s submission of ANDA No. 212296 with a Paragraph IV certification to the FDA, asserting that Plaintiff's patents are invalid, unenforceable, or will not be infringed by the proposed generic product. The complaint notes that Defendant’s notice letter does not contest infringement of the '593 and '649 patents, suggesting the dispute for those patents will center on validity.

Case Timeline

Date Event
2009-03-03 Priority Date for '593 and '649 Patents
2011-04-05 Priority Date for '058 Patent
2012-01-24 '593 Patent Issued
2013-02-05 '649 Patent Issued
2014-02-18 '058 Patent Issued
2018-10-01 Plaintiff received Defendant's Paragraph IV Notice Letter
2018-11-09 Complaint Filed

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

U.S. Patent No. 8,101,593 - "Formulations of Deoxycholic Acid and Salts Thereof"

Issued January 24, 2012 ('593 Patent)

The Invention Explained

  • Problem Addressed: The patent addresses the physical instability of aqueous solutions containing low concentrations (less than 5% w/v) of sodium deoxycholate, an active ingredient used for dissolving fat deposits. At these low concentrations, which are desirable for safe and effective treatment, the compound tends to precipitate out of solution, which limits the product's shelf life and suitability for injection ('593 Patent, col. 11:55-68).
  • The Patented Solution: The invention solves this precipitation problem by adjusting the pH of the aqueous formulation to a specific alkaline range of about 8.0 to 8.5. Maintaining the pH in this range is disclosed to substantially inhibit precipitation and stabilize the low-concentration solution for long-term storage and use ('593 Patent, Abstract; col. 5:9-14). The patent's figures graphically demonstrate the stability of pH over time in various formulations ('593 Patent, Fig. 1A-1F).
  • Technical Importance: This solution provided a method to create a commercially viable, ready-to-use injectable product for localized fat reduction that is stable during storage, avoiding the need for practitioners to dilute a more concentrated, stable formulation just prior to use ('593 Patent, col. 5:1-8).

Key Claims at a Glance

  • The complaint asserts at least one claim of the '593 patent (Compl. ¶26). Independent claim 1 is the sole independent claim.
  • Essential elements of Independent Claim 1:
    • An aqueous pharmaceutical formulation consisting of:
    • from about 0.5% w/v to about 1.5% w/v deoxycholate;
    • and at least one pharmaceutically acceptable excipient and/or carrier;
    • wherein the formulation has a pH of from about 8.0 to about 8.5.
  • The complaint does not explicitly reserve the right to assert dependent claims, but infringement is alleged for "one or more claims" (Compl. ¶46).

U.S. Patent No. 8,367,649 - "Formulations of Deoxycholic Acid and Salts Thereof"

Issued February 5, 2013 ('649 Patent)

The Invention Explained

  • Problem Addressed: As a continuation of the application leading to the '593 patent, the '649 Patent addresses the same technical problem: the precipitation of sodium deoxycholate in low-concentration aqueous solutions intended for injection to reduce fat deposits ('649 Patent, col. 11:55-68).
  • The Patented Solution: The '649 patent claims a similar solution, stabilizing the formulation by controlling its pH. However, this patent claims a narrower, more specific pH of "about 8.3," which is taught to inhibit precipitation and ensure the formulation's stability and suitability for injection ('649 Patent, Abstract; col. 11:47-54). The specification, identical to the '593 patent, provides experimental data showing the stability of various formulations over time and temperature ('649 Patent, Figs. 4-7).
  • Technical Importance: This patent refines the technical solution by identifying a more precise pH target, potentially offering an optimized balance of stability and physiological compatibility ('649 Patent, col. 18:46-54).

Key Claims at a Glance

  • The complaint asserts at least one claim of the '649 patent (Compl. ¶26). Independent claim 1 is the sole independent claim.
  • Essential elements of Independent Claim 1:
    • An aqueous pharmaceutical formulation consisting of:
    • from about 0.5% w/v to about 1.5% w/v deoxycholate;
    • and at least one pharmaceutically acceptable excipient and/or carrier;
    • wherein the formulation has a pH of about 8.3.
  • The complaint alleges infringement of "one or more claims" of the patent (Compl. ¶82).

U.S. Patent No. 8,653,058 - "Compositions Comprising Deoxycholic Acid and Salts Thereof Suitable for Use in Treating Fat Deposits"

Issued February 18, 2014 ('058 Patent)

The Invention Explained

The '058 Patent is also directed to stabilizing aqueous formulations of deoxycholic acid salts against precipitation, specifically for concentrations from 0.4% w/v to less than 2% w/v. The patented solution involves maintaining the formulation's pH in a preferred range of 8.1 to 8.5, optionally using a buffer. The claims also recite specific formulations that include excipients such as a preservative (e.g., benzyl alcohol) and an agent to provide an isotonic solution (e.g., sodium chloride) ('058 Patent, Abstract; col. 9:5-24).

Key Claims at a Glance

  • Asserted Claims: The complaint alleges infringement of at least one claim of the '058 patent (Compl. ¶26). The patent includes independent claims 1, 2, 10, 11, 12, 14, and 15. The complaint notes that Slayback's notice letter does not contest infringement of claim 2 (Compl. ¶26).
  • Accused Features: The accused features are the composition of the Slayback ANDA Product, including its deoxycholic acid salt concentration, pH, and the presence of other excipients, which are alleged to match the claimed formulations (Compl. ¶¶ 28, 110).

III. The Accused Instrumentality

Product Identification

The "Slayback ANDA Product" is the subject of Slayback's ANDA No. 212296, intended to be a generic version of Kythera's Kybella® product (Compl. ¶¶ 2, 21).

Functionality and Market Context

The product is a deoxycholic acid injection indicated for the "improvement in the appearance of moderate to severe convexity or fullness associated with submental fat in adults" (Compl. ¶21). The complaint alleges that by filing its ANDA, Slayback has represented to the FDA that its product has the same active ingredient, dosage form, and strength as Kybella®, and is bioequivalent (Compl. ¶28). The product is intended for the same market and indication as Kybella®, which is protected by the patents-in-suit listed in the FDA's Orange Book (Compl. ¶¶ 22, 29).

IV. Analysis of Infringement Allegations

The complaint does not provide a claim chart or detailed element-by-element infringement analysis. Instead, it asserts a general theory of infringement based on information from Slayback's confidential ANDA submission and the nature of the proposed generic product.

For the '593 and '649 patents, the complaint's infringement theory is straightforward. It alleges that because the Slayback ANDA Product is a generic version of Kybella®, it will necessarily be formulated with a deoxycholic acid concentration and pH that falls within the scope of the patents' claims (Compl. ¶¶ 38, 74). Critically, the complaint states that Slayback's Paragraph IV notice letter "does not contest infringement of the '593 and '649 patents" (Compl. ¶26). This strongly suggests that the central dispute for these two patents will be over their validity, not whether Slayback's product infringes.

For the '058 patent, the infringement analysis is more contested. The complaint alleges that Slayback's product will infringe at least one claim of the '058 patent (Compl. ¶110). However, it also notes that Slayback's notice letter asserts non-infringement of claims 1 and 3-15, while not contesting infringement of claim 2 (Compl. ¶26). This creates a potential point of contention regarding whether the specific combination of deoxycholic acid concentration, pH, and excipients in Slayback's proposed product meets the limitations of the '058 patent's more detailed formulation claims.

No probative visual evidence provided in complaint.

V. Key Claim Terms for Construction

Term: "consisting of" (from Claim 1 of '593 and '649 Patents)

  • Context and Importance: This is a closed transition phrase in claim drafting, meaning the formulation must contain the listed elements and nothing more, apart from impurities. Its construction is critical because if Slayback's ANDA product includes additional, unlisted excipients (beyond carriers or those present in trace amounts), it could be found to not infringe. Practitioners may focus on this term as a potential avenue for a non-infringement defense.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specifications of the patents at times use the open-ended term "comprising" when discussing formulations in a general sense, which could be argued to suggest the inventors did not intend a strictly closed scope in all contexts ('593 Patent, col. 5:15-16).
    • Evidence for a Narrower Interpretation: The use of "consisting of" in the claim itself is extremely strong evidence for a narrow, closed-ended interpretation, as this is a well-established term of art in patent law. This language strongly suggests the exclusion of any unrecited ingredients that materially affect the formulation's properties.

Term: "pH of about 8.3" (from Claim 1 of '649 Patent)

  • Context and Importance: The precise pH is central to the patent's claimed invention for achieving stability. The scope of "about" will determine whether Slayback's product, which may have a pH that is close but not identical to 8.3, infringes.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The word "about" explicitly provides some flexibility beyond the exact numerical value. The specification discusses the general principle of raising the pH to achieve stability and provides examples at pH 8.0 and 8.5, which could support an argument that "about 8.3" encompasses a range around that value ('649 Patent, Table 8).
    • Evidence for a Narrower Interpretation: The prosecution history (not provided) could have created a distinction between the broader range of the '593 patent ("8.0 to 8.5") and the specific "about 8.3" of the '649 patent. A defendant might argue that "about 8.3" was chosen to capture a narrower, optimal point and should be construed narrowly, for example, by considering the precision of the pH measurements disclosed in the patent's examples ('649 Patent, Table 9, showing pH measurements to two decimal places).

VI. Other Allegations

  • Indirect Infringement: The complaint alleges that Slayback will induce and contribute to infringement of all three patents. The inducement theory is based on Slayback's knowledge of the patents from the Orange Book listing and its intent for the ANDA product to be used for the patented method of fat reduction, as this is its only approved indication (Compl. ¶¶ 40, 76, 112). The contributory infringement allegation is based on the assertion that the ANDA product is especially made for this infringing use and is not a staple article of commerce with substantial non-infringing uses (Compl. ¶¶ 41, 77, 113).
  • Willful Infringement: The complaint alleges that Slayback's infringement is and will be willful. This is based on Slayback's alleged actual notice of the patents-in-suit prior to filing its ANDA, as evidenced by the patents' listing in the FDA's Orange Book and Slayback's own Paragraph IV certification letter (Compl. ¶¶ 71, 107, 143, 144).

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

  • A central question for the '593 and '649 patents will be one of validity: given that Slayback does not appear to contest infringement, can it demonstrate by clear and convincing evidence that the claims are invalid, likely on grounds of obviousness, for claiming a specific pH range to stabilize a known compound (deoxycholic acid) to solve a known problem (precipitation)?
  • A key issue for the '058 patent will be one of claim scope and infringement: does the specific formulation disclosed in Slayback’s confidential ANDA fall within the scope of the asserted '058 claims, particularly in light of the restrictive "consisting of" language and the specific excipients recited in different claims? The outcome may turn on the precise definition of terms like "about" and the presence or absence of unrecited ingredients in the accused product.
  • A foundational technical and legal question for the entire case will be the level of ordinary skill and obviousness: would a person of ordinary skill in the art of pharmaceutical formulations, knowing of deoxycholic acid's properties and the precipitation issue at low concentrations, have been motivated to adjust the pH to the claimed alkaline range with a reasonable expectation of success, thereby rendering the inventions obvious?