Broken chain of priority invalidates patent

The filing of a continuing patent application (i.e., continuation, divisional, or continuation in part application) may have significant benefits for the patent owner.  For example, these continuing applications may be used to secure patent protection for the previously unexamined subject matter (i.e., non-elected inventions) or seek broader patent protection for what has already been granted.  However, to take advantage of the practice of filing continuing patent applications, strict adherence to patent laws and rules for claiming priority to the earlier filed patent application must be followed.  Otherwise, the earlier publication or issued patents may invalidate the follow-on continuing patent application.

Each of the patent applications in the family must have a proper priority claim continually linking it to the earlier applications in the chain, not just the patent at issue.

In Medtronic v. Edwards (Fed. Cir. Jan. 22, 2014), the patent owner had filed a series of patent applications all claiming priority back to French application 1b and International Application 2b.  (See patent family history below). Unfortunately, the patent owner failed to follow the strict requirements for properly claiming priority back to International Application 2b, and thus, the publication of the French Application 1b and the published International Application 2b became prior art against its own subsequent patent applications (i.e., child patent applications), namely, U.S. Patent Application 10 (Pat. No. 7,892,281) which is the patent at issue in this case. The Federal Circuit affirmed the district courts holding that this patent is invalid for being anticipated by the earlier patents and patent publications, namely, French Application 1b and International Application 2b.

The patent statute (35 U.S.C. § 120) allows a later filed patent application to claim the benefit of an earlier filing date in the United States, if among other requirements, “it contains or is amended to contain a specific reference to the earlier filed application … submitted at such time during the pendency of the application.” (Emphasis added).  Additionally, the “specific reference” requirement mandates “each [intermediate] application in the chain of priority to refer to the prior applications.”  Encyclopedia Britannica, 609 F.3d 1345, 1352 (Fed. Cir. 2010).

U.S. Patent Application 10 issued as U.S. Pat. No. 7,892,281.  This patent which is the patent at issue contained a complete and proper chain of priority referring back to each of the prior patent applications. However, the intervening patent applications, namely, U.S. Patent Applications 6 and 8 failed to provide a specific reference to the earlier filed applications in the priority chain.  In particular, U.S. Patent Applications 6 and 8 referenced International Application 2b but failed to reference U.S. Patent Application 4.  As such, the court held that U.S. Pat. No. 7,892,281 is not entitled to claim the priority of International Application 2b.  Thus,  the French Application 1b and International Application 2b were published more than one year before the filing date of the patent application that was issued as U.S. Pat. No. 7,892,281 invalidated U.S. Pat. No. 7,892,281.

To try and remediate the situation, the patent owner argued that the claim of priority in the intervening patent applications did refer to the (missing) prior patent application(s).  In particular, U.S. Patent Applications 6 and 8 made a specific reference to International Application 2b but not to U.S. Application 4.  As such, the patent owner argued that a reference to “this application” in the claim of priority language of U.S. Applications 6 and 8 referred to U.S. Patent Application 4.  However, prior opinions of the Federal Circuit used and interpreted the phrase “this application” in this context always in the self-referential sense to mean the “present application” and not to a different, earlier filed application.  Put simply, the Federal Circuit disagreed with the patent owner.

The patent owner also argued that the exact verbiage of the claim of priority should be viewed from the perspective of the “reasonable person” and how he/she would read the claim of priority.  The Federal Circuit declined to adopt the “reasonable person” test to interpret the sufficiency of the priority claim. The reason is that the patentee is the person best suited to understand the genealogy and relationship of the application.  The “reasonable person” test would misplace the burden on the public.

The patent owner also pointed to the Macdermid Printing case wherein the claim of priority failed to use the words “claims the benefit of” as recommended by the USPTO but yet the court found the claim of priority to be effective.  The Federal Circuit distinguished that case from the present dispute in that the Macdermid Printing case had a proper priority claim except that they did not use the magic words.  In the present case, the patent owner failed to identify the prior applications and their relationships.

Under current patent laws and rules, the claim of priority does not have per se magic words that must be used.  However, each of the patent applications in the family must have a proper priority claim continually linking it to the earlier applications in the chain, not just the patent at issue.  Moreover, since the passage of the America Invents Act, patent attorneys appear to be using the Application Data Sheet provided by the USPTO.  The Application Data Sheet includes a section for claiming priority and greatly simplifies the process.  As such, we should not see many of these types of disputes for patent applications filed under the America Invents Act.

I invite you to contact me with your patent questions at (949) 433-0900 or [email protected] Please feel free to forward this article to your friends. As an Orange County Patent Lawyer, I serve Orange County, Irvine, Los Angeles, San Diego, and surrounding cities.