A patentee may apply for a reissued patent that adds new dependent claims even when the independent claim remains unchanged.

The addition of one or more new dependent claims as a hedge against possible patent invalidity is a valid reason for reissue of a patent under 35 U.S.C. § 251. Reissue under Section 251 requires that: (1) the original patent must be wholly or partly inoperable or invalid; and (2) the defective, inoperative, or invalid patent must have arisen through error without deceptive intent. In a reissue proceeding before the U.S. Patent and Trademark Office (PTO), the applicant requested a reissued patent that simply added a new dependent claim and maintained all of his original claims. The Board of Patent Appeals and Interferences affirmed the patent examiner’s decision that this was not a cause for reissue. The PTO found that omission of a dependent claim was not error that rendered a patent “partially inoperative,” because the scope of the overall patent remained unchanged. There was no issue of deceptive intent.

The Federal Circuit reversed and remanded the case. The Federal Circuit held that omission of a dependent claim, when done without deceptive intent, is an error that is correctible by reissue under Section 251. The Federal Circuit concluded that omission of a dependent claim does render a patent “partly inoperative,” because the absence of such a claim can lead to the patent’s failure to protect the disclosed invention to the full extent allowed by law. Because a reissue that only adds dependent claims does not broaden the overall scope of a patent, a reissued patent that adds dependent claims could be allowed at any time during a patent term. In dicta, the Federal Circuit noted the concern of a generic pharmaceutical company amicus that this ruling could limit the public’s ability to rely on what has been claimed in an issued patent. However, the Federal Circuit dismissed this concern with reference to 35 U.S.C. § 252, under which the courts may protect investments made before the grant of a reissued patent.

A copy of the opinion can be found here.