In Re: Iftikar Khan, Nazin Khan

Docket No. 2017-2207

February 15, 2018


Brief summary: FC panel affirmed the Board decision that the proposed reissue claims were attempting to improperly recapture subject matter surrendered during prosecution of the parent patent.

Summary: Drs. Khan (the Kahns) appealed Board decision affirming the examiner’s rejection of the claims of their reissue application of US 8,282,591 related to “arteriovenous shunts” for use in hemodialysis patients. The limitation in question here is the requirement for a “cylindrical cuff” in the shunt which was added as an amendment during prosecution of the ‘591 patent with the argument “that none of the references disclose” the same. The examiner maintined the rejections and the Khans appealed. The Board reversed the examiner and allowed the claims. The Khans then filed reissue claims 21-41, none of which “expressly recites the ‘cylindrical cuff’ limitation.” The examiner rejected the claims “under § 251 as recapturing subject matter surrendered during prosecution of the ‘591 patent” and obviousness, and the Board affirmed. Section 251 “permits a patentee to seek a broadening reissue of a patent where, ‘through error and without any deceptive intent,’ the patentee originally claimed ‘less than he had a right to claim’” (In re Youman, FC 2012). However, the “recapture rule…bars a patentee from recapturing subject matter, through reissue, that the patentee intentionally surrendered during the original prosecution to overcome the prior art.” Whether “recapture has occurred” is determined by a three-step analysis: 1) “determine whether and in what ‘aspect the reissue claims are broader than the original patent claims”; 2) determine “whether the broader aspects of the reissue claims relate to surrendered subject matter”; and 3) “determine whether the reissue claims were materially narrowed in other respects, so that the claims may not have been enlarged, and hence avoid the recapture rule” (Greenliant, FC 2012). Under the first step of the analysis, the FC panel determined that proposed reissue claims 21, 29, 38 and 39, by not including the “cylindrical cuff” limitation, were broader than those of the ‘591 patent. The presence of the “cylindrical cuff” limitation in dependent claims could not save those claims since “‘the presence of a dependent claim that adds a particular limitation raises a presumption that the limitation in in question is not found in the independent claim’, not that the limitation is found in the independent claim” (Liebel-Flarsheim, FC 2004). The FC panel then determined that the “cylindrical cuff” limitation “relate[s] to surrendered subject matter” in that the Khans amended the claims to include that limitation and “relied on this limitation to distinguish” the claims over the prior art. The FC did not address step three since the Kahns did not not argue that point. The FC panel also found the Kahns waived arguments regarding certain dependent claims because those were not separately argued (“[a] statement which merely points out what a claim recites will not be considered an argument for separate patentability of the claim” (37 CFR § 41.37(c)(1)(iv)). The FC panel therefore affirmed the Board decision without reaching the obviousness issues.

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