US patent unenforceable for inequitable conduct as a result of contradictory submissions

Belcher Pharmaceuticals, LLC v. Hospira, Inc. [2021], CAFC 20-1799

A US formulation patent owned by Belcher Pharmaceuticals was found unenforceable by the US Courts of Appeal of the Federal Circuit (CAFC) due to inequitable conduct as a result of contradictory submissions to the patent office and regulatory authority.

US patent unenforceable for inequitable conduct as a result of contradictory submissions

Belcher's patent related to a high-pH formulation of L-epinephrine (L-adrenaline) and was granted with a claim to a formulation of pH 2.8-3.3. The formulation of L-epinephrine was also the subject of a new drug application before the FDA.

Hospira, who were separately seeking FDA approval for their own L-adrenaline formulation, submitted that Belcher's patent was unenforceable for inequitable conduct.

During prosecution of the patent application, Belcher had argued that the skilled person would not expect a preservative-free, sulfite-free, high-pH formulation to be stable and therefore would not look at a formulation of pH above 2.8.

Belcher had separately submitted a new drug application (NDA) to the FDA prior to filing the patent application. Initially, the NDA sought approval for a formulation with pH 2.4-2.6 supported by stability data for a preservative-free formulation with pH 3.1-3.3. After receipt of a query from the FDA on whether the high-pH reference product was applicable to the lower pH formulation, Belcher amended their NDA to relate to a formulation of pH 2.8-3.3. Belcher additionally submitted arguments that changes to pH within the range of 2.4-3.3 would only have a minor effect on stability, directly contradicting their arguments submitted to the USPTO.

In the US, applicants and attorneys have a duty to disclose information that is material to patentability. Intentional failure to comply with the duty of disclosure is considered to be inequitable conduct and can be fatal to a US patent / patent application. US case law has established a two pronged test for inequitable conduct:

  1. Intentionality - did the patent holder intend to deceive the patent office by withholding the document?
  2. Materiality - was the document material to patentability of the invention?

Therefore, inequitable conduct includes both (1) intentionally failing to disclose information to the USPTO that is material to the patentability of an application and also (2) intentionally presenting incorrect material facts to the USPTO.

In their decision, the CAFC considered both prongs of the test. Firstly, Belcher's CSO was involved in both the NDA and patent prosecution. The CSO admitted that he was aware of the high pH prior art formulation and the stability data submitted for the reference product as part of the NDA. The CSO also admitted he was aware that another company had already introduced a high pH adrenaline formulation to the market (pH 2.2-5.0). As such, it was determined that the CSO (on behalf of Belcher) had intentionally tried to deceive the USPTO.

Secondly, the prior art was considered material to the patentability of the invention since it rendered Belcher's patent obvious. On this point, Belcher tried to argue that the prior art was immaterial, however this was unsuccessful as a result of their own arguments during prosecution that pH was critical. Therefore, both the district court and the federal circuit agreed that this was clearly inequitable conduct and therefore that the patent was unenforceable.

This case confirms the importance of the duty of disclosure in the US and highlights the potential difficulties in having the same person responsible for both patent prosecution and regulatory submissions.

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