Background
Pfizer Ireland Pharmaceuticals Unlimited Company, the owner of Australian Patent No. 2005280034, and its exclusive licensee, Pfizer Australia Pty Ltd, sued Samsung Bioepis, Organon, Merck Sharp & Dohme, and Arrow entities over BRENZYS, a biosimilar form of etanercept. Pfizer’s patent concerned methods for producing therapeutic proteins and polypeptides in large-scale mammalian-cell culture. Pfizer alleged that the respondents’ two manufacturing processes infringed claims 1, 2, 5, 7, 8, 33, 37–40, 42, 45, 46, and 49.
The respondents denied infringement and cross-claimed for revocation, alleging lack of inventive step, fair basis, utility, sufficiency, clarity, and disclosure of the best method. Pfizer abandoned proposed narrowing amendments during trial but continued to seek unopposed amendments correcting clerical errors and obvious mistakes. Because the patent expired on 26 August 2025, injunctive relief was no longer at issue, and the proceeding addressed liability separately from any question of monetary relief.
The Court’s Holding
Justice Burley held that Pfizer’s infringement case failed because it did not prove that the respondents’ manufacturing processes contained every essential element of claim 1. In particular, Pfizer failed to establish the element requiring the culture to reach a specified percentage of its maximum possible viable cell density before conditions changed. Pfizer also failed to establish the claim’s “medium containing glutamine” element for one process used to manufacture a number of batches.
On validity, the Court held that every asserted claim except claim 2 lacked an inventive step. The respondents did not establish their other invalidity challenges based on fair basis, inutility, insufficiency, lack of clarity or definition, or failure to disclose the best method. The Court also allowed Pfizer’s correcting amendments, finding that they addressed clerical errors or obvious mistakes and did not materially affect the patent’s scope or content. The parties were directed to submit proposed orders implementing the reasons and addressing the proceedings’ further conduct and costs.
Key Takeaways
- A patentee must prove that the accused process contains every essential claim element; failure on one element defeats infringement.
- All asserted claims other than claim 2 were invalid for lack of inventive step, although the respondents’ remaining validity challenges failed.
- The Court permitted corrections of clerical errors and obvious mistakes because they did not materially alter the patent rights.
Why It Matters
The decision illustrates the evidentiary difficulty of proving infringement of bioprocess patents, particularly where a claim depends on a hypothetical biological benchmark such as the maximum viable cell density achievable under different culture conditions. Evidence that an accused process produces the same therapeutic protein is insufficient unless each claimed process limitation is proved.
It also shows that validity grounds operate independently: most asserted claims failed for want of inventive step even though the patent survived challenges concerning fair basis, utility, sufficiency, clarity, and best method.