Azurity Pharmaceuticals Inc v. Heron Therapeutics Inc

1. Case Identification

• Case #: PGR2025-00035
• Patent #: 12,115,254
• Filed: February 28, 2025
• Petitioner(s): Azurity Pharmaceuticals, Inc., Azurity Pharma India LLP, Slayback Pharma LLC
• Patent Owner(s): Heron Therapeutics, Inc.
• Challenged Claims: 1-30

2. Patent Overview

• Title: Emulsion Formulations for Intravenous or Parenteral Administration
• Brief Description: The ’254 patent relates to injectable pharmaceutical emulsion formulations containing the anti-nausea drug aprepitant. The independent claims require specific weight percentages of aprepitant and a high ratio of emulsifier to aprepitant.

3. Grounds for Unpatentability

Ground 1: Obviousness over Zhou, Washington, Bagwe, and Weng - Claims 1-30 are obvious over Zhou in view of Washington, Bagwe, and Weng.

• Prior Art Relied Upon: Zhou (CN102379845), Washington (a 1996 journal article), Bagwe (a 2001 journal article), and Weng (a 2012 journal article).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Zhou is a nearly anticipatory reference that discloses injectable aprepitant microemulsions with all the key components recited in the challenged claims: aprepitant, an emulsifier (egg yolk phospholipid), an oil (soybean oil), a co-surfactant (ethanol), and water. Zhou disclosed overlapping or very close concentration ranges for aprepitant (0.05-2 wt%) and oil (5-30 wt%). The primary difference is that the ’254 patent claims a high emulsifier-to-aprepitant ratio (e.g., 20:1 to 25:1 in claim 1), which implies an emulsifier concentration of about 14-20 wt%. Zhou explicitly taught a lower emulsifier range of 0.5-10 wt%.
  • Motivation to Combine (for §103 grounds): A Person of Ordinary Skill in the Art (POSA) would combine the teachings to improve the stability and drug-loading capacity of Zhou's aprepitant formulation. Washington taught that aprepitant, as a drug poorly soluble in both oil and water, must be loaded at the oil-water interface, requiring a large interfacial surface area for stability and dissolution. It was well-known that increasing emulsifier concentration reduces droplet size, thereby increasing this crucial interfacial area. Bagwe explicitly taught that conventional emulsions could contain emulsifier concentrations of 1-20 wt%, providing the explicit range that a POSA would explore to optimize Zhou's formulation. Weng reinforced that lecithin is a preferred emulsifier. A POSA would therefore have been motivated to increase the emulsifier concentration in Zhou's formulation into the claimed range as a matter of routine optimization to solve the known stability and loading problems.
  • Expectation of Success (for §103 grounds): A POSA would have a reasonable expectation of success because modifying emulsifier concentration to optimize stability was a known technique, and the target concentration range (14-20 wt%) fell squarely within conventional ranges disclosed by references like Bagwe.

Ground 2: Lack of Written Description and Enablement - Claims 1-30 are unpatentable under 35 U.S.C. §112.

• Core Argument for this Ground: Petitioner contended that the ’254 patent faces a "patentability quandary." If the claims are deemed non-obvious, it must be because the art of creating stable aprepitant emulsions is highly unpredictable. Petitioner cited Patent Owner's own arguments from previous litigation and prosecution, where it characterized emulsions with 14% or 15% emulsifier as "critical," "unprecedented," "unexpected," and the result of overcoming industry skepticism and failure. The currently challenged claims, however, recite a broad range that encompasses even higher emulsifier concentrations (up to 20 wt%) and ratios greater than 20:1. Petitioner argued that for such a purportedly unpredictable and "skeptical" field, the ’254 patent’s specification fails to demonstrate possession or provide an enabling disclosure for the full scope of the claims. The patent contains no working examples of stable emulsions with more than 15 wt% emulsifier or a ratio greater than 20:1. This lack of exemplification and guidance, viewed against the Patent Owner's own assertions of unpredictability, means the specification does not satisfy the written description and enablement requirements for the full claimed scope.

4. Key Claim Construction Positions

• "emulsion": Petitioner asserted that the patent's own specification expressly defines "emulsion" as a "colloidal dispersion of two immiscible liquids in the form of droplets, whose diameter, in general, is between 10 nanometers and 100 microns." Petitioner argued this definition is critical because it broadly encompasses macro-, micro-, and nanoemulsions. This construction preempts any attempt by the Patent Owner to distinguish prior art, such as Zhou, by arguing it relates to "microemulsions" while the patent claims "emulsions," as the patent’s own definition treats them as inclusive.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial would be inappropriate under both §314(a) (Fintiv factors) and §325(d) (Advanced Bionics factors).
• §314(a): Petitioner stated its intent to file a Sotera stipulation in the parallel district court litigation upon institution. This stipulation would prevent Petitioner from pursuing the same grounds or any grounds that could have reasonably been raised in the PGR, a factor that strongly weighs against discretionary denial.
• §325(d): Petitioner contended that the same art and arguments were not previously presented to the USPTO. While Zhou was cited in an Information Disclosure Statement (IDS), the Examiner never issued an obviousness rejection based on it and instead allowed the claims based on other reasoning. Furthermore, the grounds for Lack of Written Description and Lack of Enablement are entirely new and were never considered during prosecution.

6. Relief Requested

• Petitioner requests institution of Post Grant Review and cancellation of claims 1-30 of the ’254 patent as unpatentable.