In Natural Alternatives International, Inc. v. Iancu, Natural Alternatives challenged the Board’s priority determination that amending the benefit claim of a parent application to delete reference to earlier applications affected the priority date of the child application. The Federal Circuit affirmed.

Natural Alternatives filed a family of eight patent applications, each claiming priority to the first application through the preceding applications. After filing its sixth application, Natural Alternatives amended its fifth application by deleting the claim of priority to the fourth through first applications. The sixth through eighth applications were not similarly amended and eventually issued claiming priority to the first through fifth applications.

Another party initiated an inter partes reexamination against the patent that issued from the eighth application. In the request, the party alleged the priority claim was defective. The Board agreed. It determined because the eighth application relied on the amended fifth application for priority, which had been purposefully amended to terminate a claim of priority to the first through fourth applications, the eighth application was not entitled to the benefit of the first application’s filing date.

The Federal Circuit affirmed. The Court rejected Natural Alternative’s argument that a priority date “vests” as conflating claiming priority and demonstrating its entitlement to priority. It further reasoned that, because the eighth application claimed benefit to the first by way of the fifth application, and the fifth had been amended to terminate a claim of priority to the first, the eight application lacked “specific reference” to establish priority to the first application.