In Maquet Cardiovascular LLC v. Abiomed Inc., the Federal Circuit issued a significant ruling that reshapes how prosecution history disclaimer applies across related patents. The decision vacated a district court judgment of non-infringement and provides key insights for patent prosecutors and litigators alike.
Background of the Case
Maquet Cardiovascular sued Abiomed for infringing claims in both U.S. Patent No. 10,238,783 and its parent, U.S. Patent No. 9,789,238. The district court had interpreted the claims using prosecution history from related patents, applying two negative limitations that restricted claim scope. These limitations ultimately led to a ruling of non-infringement in favor of Abiomed.
However, on appeal, the Federal Circuit reversed this approach, emphasizing that prosecution disclaimer should not automatically extend across related patents unless their claim language is substantially similar.
Key Takeaways from the Decision
This ruling reinforces important principles regarding prosecution disclaimer:
1. Parity Between Claims Matters
Prosecution disclaimer only carries over from one patent to another if there is substantial similarity in claim language. Without parity, applying limitations from an earlier patent to a later one is improper.
2. High Standard for Disclaimer
For a disclaimer to be valid, it must be clear and unmistakable. Mere silence or failure to dispute an examiner’s statement does not constitute disclaimer. This means patent applicants do not necessarily need to respond to every examiner’s reason for allowance.
3. IPR Statements Must Be Specific
The Federal Circuit also addressed prosecution disclaimer in the context of inter partes review (IPR). While statements made during IPR can contribute to disclaimer, they must meet the same high threshold of clarity. Vague or broad statements generally won’t be enough to limit claim scope.
What This Means for Patent Prosecutors
For patent professionals, this case provides a roadmap for avoiding unintended disclaimers:
- Differentiate claim language across related patents to reduce the risk of unintended claim limitations.
- Be mindful of statements made during prosecution and IPR, ensuring they are not overly broad or ambiguous.
- Recognize that silence is not necessarily acquiescence, meaning there may not always be a need to contest an examiner’s reasons for allowance.
The Maquet decision offers critical guidance for maintaining control over claim scope and ensuring that prosecution history does not unnecessarily limit patent rights.