A Mixed Bag: Some Claims Found Unpatentable But Others Are Patentable

• Published date: 18 November 2021
• Subject Matter: Intellectual Property, Patent
• Law Firm: Finnegan, Henderson, Farabow, Garrett & Dunner, LLP
• Author: Ms Melissa Santos, Jill K. MacAlpine, Amanda K. Murphy, Hira Javed and Stacy Lewis

Holding

In Liquidia Technologies, Inc. v. United Therapeutics Corp., IPR2020-00770, Paper 45 (P.T.A.B. Oct. 8, 2021), the Patent Trial and Appeal Board ("PTAB") issued a Final Written Decision ("FWD") finding seven of the challenged claims unpatentable and two of the challenged claims not unpatentable.

Background

Petitioner challenged claims 1-9 of U.S. Patent No. 9,604,901 ("the '901 Patent") on two obviousness grounds: Phares and Moriarty/Phares. Claim 1, the only independent claim, read:

1. A pharmaceutical batch consisting of treprostinil or a salt thereof and impurities resulting from (a) alkylating a benzindene triol, (b) hydrolyzing the product of step (a) to form a solution comprising treprostinil, (c) contacting the solution comprising treprostinil from step (b) with a base to form a salt of treprostinil, (d) isolating the salt of treprostinil, and (e) optionally reacting the salt of treprostinil with an acid to form tresprostinil, and wherein the pharmaceutical batch contains at least 2.9 g of treprostinil or its salt.

Claims 6 and 7, the two claims that survived the inter partes review ("IPR") challenge to the '901 patent, read:

6. A method of preparing a pharmaceutical product from a pharmaceutical batch as claimed in claim 1, comprising storing a pharmaceutical batch of a salt of treprostinil as claimed in claim 1 at ambient temperature, and preparing a pharmaceutical product from the pharmaceutical batch after storage.

7. A method as claimed in claim 6, wherein the salt of treprostinil is a diethanolamine salt.

The examiner issued an anticipation rejection based on Moriarty during prosecution of the '901 patent. Since the claims are drafted in product-by-process format, determination of patentability is based only on the product without regard to the process. In re Thorpe, 777 F.2d 695, 697 (Fed. Cir. 1985). According to the examiner, "[a]lthough the method of Moriarty and the steps recited in the instant claims are not identical, the product obtained is the same." FWD at 10. The examiner also rejected claims as obvious over Moriarty and Phares.¹ The applicant overcame the rejections with claim amendments and expert declarations.

PTAB

The PTAB construed "pharmaceutical batch" in claim 1 to not require storage stability, contrary to Patent Owner's argument. Id. at 20. The PTAB also construed the terms "storing" and "storage" to require actual storage for a period of at least three months. Id. at 25. This was different from the way the PTAB...