Federal Circuit Limits Cross-Family Prosecution Disclaimer
In Maquet Cardiovascular LLC v. Abiomed Inc., the Federal Circuit clarified prosecution history disclaimer across related patents. The court vacated a district court judgment of non-infringement. It also provided guidance for patent prosecutors and litigators.
Case Background and District Court Ruling
Maquet sued Abiomed for infringing U.S. Patent No. 10,238,783 and its parent, U.S. Patent No. 9,789,238.
The district court relied on prosecution history from related patents. It applied two negative limitations to the asserted claims. Those added limitations narrowed claim scope. As a result, the court found non-infringement in favor of Abiomed.
Federal Circuit Reverses the Claim Construction
On appeal, the Federal Circuit rejected that approach. The court emphasized that prosecution disclaimer does not automatically extend across related patents.
Instead, disclaimer applies only when claim language is substantially similar.
Key Takeaways on Prosecution History Disclaimer
This decision reinforces several important principles.
Substantial Similarity Between Claims Is Required
First, parity between claims matters. Prosecution disclaimer carries over only when claim language is substantially similar. Without that similarity, importing limitations from an earlier patent is improper.
Disclaimer Requires Clear and Unmistakable Statements
Second, disclaimer must be clear and unmistakable. Mere silence does not create disclaimer.
Failure to dispute an examiner’s statement is not enough. Therefore, applicants do not need to respond to every reason for allowance.
IPR Statements Must Meet the Same High Standard
Third, the court addressed disclaimer during inter partes review. Statements made during IPR can support disclaimer. However, they must meet the same clear and unmistakable standard. Vague or broad statements generally will not limit claim scope.
Practical Guidance for Patent Prosecutors
This case offers practical guidance for patent professionals. First, differentiate claim language across related patents when appropriate. Doing so may reduce the risk of unintended limitations. Second, draft prosecution and IPR statements carefully. Avoid broad or ambiguous language that could narrow claim scope.
Finally, remember that silence is not automatic acquiescence. In many cases, there may be no need to contest every examiner comment.
Why the Maquet Decision Matters
Ultimately, Maquet helps preserve control over claim scope. It also limits the automatic spread of disclaimer across patent families.
As a result, patent owners have clearer boundaries when litigating related patents.