Summary: Removing the priority claim of one application in a chain can affect the ability of pending and subsequently filed applications to claim priority to earlier applications. 

Natural Alternatives International (“NAI”) filed a series of eight patent applications claiming priority to an original 1997 application.  NAI filed the fifth application, which was a continuation-in-part, in 2003 and the sixth application in 2008 while the fifth was still pending.  Four days after filing the sixth application, NAI amended the fifth to delete the earlier priority claim, which resulted in a longer patent term for the fifth application.  During inter partes reexamination, the examiner and the Board determined the eighth application was entitled only to the priority date of the fifth application because NAI “deliberately and expressly terminated their claim to the priority of the first four applications.” 

The Federal Circuit affirmed.  The court rejected NAI’s argument that the priority claim in the sixth application “vested” when the application was filed and the fifth application still claimed priority to the first four applications.  By amending the priority claim of the fifth application, NAI caused the subsequently filed applications to lack a specific reference to the earlier applications.  Accordingly, the eighth application was entitled only to the priority date of the fifth application, and could be rejected in view of the first application.  The court also held that NAI could not “have it both ways” by obtaining extended patent term on the fifth application while obtaining the benefit of the earliest priority date for later applications.