Obviousness And Written Description Take Down An Infringed Patent

• Published date: 06 July 2023
• Subject Matter: Intellectual Property, Food, Drugs, Healthcare, Life Sciences, Patent, Biotechnology & Nanotechnology
• Law Firm: Finnegan, Henderson, Farabow, Garrett & Dunner, LLP
• Author: Ms Adriana Burgy and Stacy Lewis

Holdings

In Azurity Pharms., Inc. v. Alkem Labs. Ltd., 2023 U.S. Dist. LEXIS 22848 (D. Del. Feb. 10, 2023), the district court held that Alkem's ANDA infringes Azurity's asserted claims, but the claims are invalid due to lack of written description support and obviousness.

Background

Azurity's claims relate to enalpril formulations. The individual claimed ingredients were known prior in the art. Azurity based its patentability on combining those ingredients into a liquid that would be stable for 12 to 24 months. Id. at *2. Representative claim 4 of the '621 patent reads:

A stable oral liquid formulation, consisting essentially of:

(i) about 0.6 to about 1.2 mg/mL enalapril or a pharmaceutically acceptable salt or solvate thereof;

(ii) a buffer to maintain the pH about 4.5 or below, wherein the buffer concentration is about 5 mM to about 20 mM;

(iii) a preservative, wherein the preservative is a paraben or a mixture of parabens; and

(iv) water;

wherein the formulation optionally comprises a sweetener, a flavoring agent, or both;

wherein the formulation is stable at about 5 ' 3' C. for at least 12 months; []

wherein the stable oral liquid formulation has about 95% w/w or greater of the initial enalapril amount and about 5% w/w or less total impurity or related substances at the end of the given storage period[; and]

wherein the buffer comprises a citrate, a phosphate, a citrate/phosphate, an acetate, a glycinate, an amino acid, or a tartrate buffer.

According to Alkem, its ANDA product does not infringe because it includes an ingredient not recited and the claim is limited in scope by the partially closed transition term "consisting essentially of" to only those ingredients that do not "materially affect the basic and novel properties of the invention." Id. at *10. Alkem's ANDA includes "a 'pH adjuster' added to ensure that the pH of the mixture is within a target range." Id. at *2-3. The ANDA "states that pH adjusters'sodium hydroxide and hydrochloric acid'should be added in an amount 'q.s.' The term 'q.s.' means 'quantum satis' or 'the quantity that's necessary.' ... Thus, sodium hydroxide and hydrochloric acid will be added as necessary to Alkem's ANDA to achieve the target pH range." Id. at *7-8.

Azurity argued that pH adjusters are only optional in Alkem's ANDA. Also, "when a pH adjuster is added, it disappears by reacting with other ingredients in the mixture such that it is no longer present in the final liquid." Id. at *3.

District Court

The...