roadblockass=”alignleft size-full wp-image-3880″ title=”roadblock” src=”” alt=”roadblock” width=”203″ height=”144″ />This past Monday the BPAI pointed out that a Patent Holder may not swear behind a patent that claims the same invention, the proper forum for such a priority contest being a patent interference proceeding. The decision, Ex parte Regents of the University of California (“Regents”) (decision here), affirmed-in-part the rejection of U.S. patent No. 5,916,912 in ex parte reexamination.  In particular, the Board held that Regents could not antedate U.S. Patent No. 5,998,474 (“Cavazza”) because the ‘912 patent and Cavazza were claiming the same patentable invention. Applying, 37 C.F.R. 41.203(a), the Board reasoned that the two patents were directed to “the same patentable invention” since a claim of the Regents patent is obvious in view of a claim of Cavazza, and vice versa. This leaves the Regents in a bind, aside from challenging the BPAI decision to the CAFC, how can an interfering patent applied in patent reexamination be overcome? One rarely elected alternative would be to pursue a patent vs. patent interference in a district court under 35 U.S.C. 291.  291 actions are rare due to the arcane nature of interferences.  Most patent owners wisely elect not to assume the uncertainty of how a district court will apply interference laws and/or administer unfamiliar interference procedures. A more palatable alternative is to file a reissue application and request an interference (a 35 U.S.C. 135(a) interference).  However, in order to adhere to 35 U.S.C. § 251, the patent owner must identify and correct a defect with the reissue application. In years past, Patent Holders may have simply alleged that the defect was the failure to present a dependent claim. Once the reissue proceeding was commenced on this basis, the interference could then be pursued.  However, pending the review of Ex parte Tanaka by the CAFC, such a practice seems like a dead end. In the case of Regents, the USPTO has concluded that interfering patents exist. Thus, it is clear that a defect as to invalidity is present in accordance with the reissue statute. Yet, unlike other bases for patent reissue, can the existence of an interfering patent alone qualify as an “error” when statutory authority exists for district courts to also address the issue?