NOTE: This disposition is nonprecedential.

United States Court of Appeals 

for the Federal Circuit ______________________ 

IN RE: IFTIKHAR KHAN, NAZIR KHAN,

Appellants

______________________ 

2017-2207

______________________ 

Appeal from the United States Patent and Trademark 

Office, Patent Trial and Appeal Board in No. 14/509,949.

______________________ 

Decided: February 15, 2018

______________________ 

 IFTIKHAR KHAN, NAZIR KHAN, Burr Ridge, IL, pro se.

 NATHAN K. KELLEY, Office of the Solicitor, United 

States Patent and Trademark Office, Alexandria, VA, for 

appellee Andrei Iancu. Also represented by MICHAEL 

SUMNER FORMAN, BENJAMIN T. HICKMAN, THOMAS W.

KRAUSE, FRANCES LYNCH. 

______________________ 

Before PROST, Chief Judge, MOORE, and CHEN, Circuit 

Judges.

PER CURIAM

Drs. Iftikhar Khan and Nazir Khan (collectively, “the 

Khans”) appeal from a decision of the United States 

Patent and Trademark Office (“PTO”) Patent Trial and 
2 IN RE: KHAN

Appeal Board (“Board”) affirming the examiner’s rejections of claims 21–41 of U.S. Patent Application No. 

14/509,949 (’949 application) seeking reissue of U.S. 

Patent No. 8,282,591 (’591 patent). Because the claims of 

the reissue application recapture surrendered subject 

matter in violation of 35 U.S.C. § 251, we affirm. 

BACKGROUND

The ’591 patent describes an “arteriovenous shunt” for 

use in hemodialysis of a patient. ’591 patent at 1:14–18. 

Typically, blood is removed from and returned to the 

patient through a “graft” connected to a vein, which poses 

dangers of infection, clotting, and hyperplasia. Id. at

1:20–36, 1:39–45, 2:1–32. The Khans’ shunt avoids these 

dangers by connecting a graft to an artery, rather than a 

vein, and passing the returned blood through a “single 

lumen venous outflow catheter” into the right atrium of a 

patient’s heart. Id. at Abstract, 2:1–5, 2:11–15, 4:14–15, 

4:32–33. 

During prosecution of the ’591 patent, the examiner 

rejected claims 1 and 17 as anticipated by U.S. Patent No.

6,102,884 (“Squitieri”). The Khans amended these claims 

to require that the “arterial graft has a first diameter,” 

the “venous outflow catheter has a second diameter 

different from said first diameter,” and the shunt includes 

a “cylindrical cuff” that “provide[s] a secure fit for said 

arterial graft first diameter and said venous outflow 

catheter second diameter.” The Khans argued Squitieri 

does not disclose this “cylindrical cuff” limitation. The

examiner then rejected claims 1 and 17 as unpatentable 

over Squitieri in view of U.S. Patent No. 5,399,173 

(“Parks”) and, later, in view of U.S. Patent No. 5,509,897 

(“Twardowski”). The Khans again argued that none of the 

references disclose the “cylindrical cuff” limitation. The 

examiner maintained the rejections. The Khans appealed 

to the Board of Patent Appeals and Interferences, which

reversed, allowing claims 1 and 17. See Ex parte Khan, 
IN RE: KHAN 3

No. 2012-6569, 2012 WL 3067934, at *3 (B.P.A.I. July 27, 

2012). 

The Khans sought reissue of the ’591 patent to include

claims to “[a] method of preparing a patient for hemodialysis” (claim 21), “[a]n arteriovenous shunt” (claim 29), “[a] 

hemodialysis system” (claim 38), and “[a] method of 

performing hemodialysis on a patient” (claim 39). None of 

the reissue claims expressly recites the “cylindrical cuff” 

limitation.

The examiner rejected reissue claims 21–41 under 

§ 251 as recapturing subject matter surrendered during 

prosecution of the ’591 patent. The examiner concluded 

reissue claims 21 and 39 recapture subject matter surrendered from patented claim 17, and reissue claims 29 

and 38 recapture subject matter surrendered from patented claim 1. The examiner also rejected claims 21, 22, 

and 25–39 for obviousness over Squitieri in view of U.S. 

Patent No. 5,509,897. The Board affirmed all of the 

rejections. It declined to separately consider the patentability of dependent claims 22, 24, 30, 40, and 41 under 

§ 251, determining the Khans had waived this argument. 

The Khans timely appealed. We have jurisdiction under 28 U.S.C. § 1295(a)(4)(A). 

DISCUSSION

I 

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, 679 F.3d 

1335, 1342 (Fed. Cir. 2012). The “recapture rule,” however, “bars a patentee from recapturing subject matter, 

through reissue, that the patentee intentionally surrendered during the original prosecution in order to overcome 

the prior art.” Id. at 1343. Whether claims of a reissue 

application implicate the recapture rule is a question of 
4 IN RE: KHAN

law we review de novo, while the underlying factual 

findings are reviewed for substantial evidence. Id.

To determine whether recapture has occurred, we apply a three-step analysis. Greenliant Sys., Inc. v. Xicor 

LLC, 692 F.3d 1261, 1267 (Fed. Cir. 2012). At step one, 

we “determine whether and in what ‘aspect’ the reissue 

claims are broader than the original patent claims.” Id. 

If so, we determine at step two “whether the broader 

aspects of the reissue claims relate to surrendered subject 

matter.” Id. At step three we “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.” Id.

Under step one, reissue claims 21 and 39 are broader 

than patented claim 17, and reissue claims 29 and 38 are 

broader than patented claim 1, because none of the reissue claims require the “cylindrical cuff” recited in the 

patented claims. The Khans’ argument that the “cylindrical cuff” limitation is retained in dependent claims cannot 

save reissue claims 21, 29, 38, and 39, since “[t]he presence of a dependent claim that adds a particular limitation raises a presumption that the limitation in question 

is not found in the independent claim,” not that the limitation is found in the independent claim. LiebelFlarsheim Co. v. Medrad, Inc., 358 F.3d 898, 910 (Fed. 

Cir. 2004) (emphasis added). 

Turning to step two, the “cylindrical cuff” omitted 

from the reissue claims relates to surrendered subject 

matter. When the examiner rejected claims 1 and 17 as 

anticipated by Squitieri, the Khans amended these claims

to require the “cylindrical cuff” and then relied on this 

limitation to distinguish over Squitieri. This constitutes 

surrender. Greenliant, 692 F.3d at 1269–71 (finding 

surrender where “[d]uring prosecution . . . , [the applicant] both amended claim 13 to add the . . . limit and 

relied on the . . . limit . . . to overcome prior art”); see also
IN RE: KHAN 5

In re Mostafazadeh, 643 F.3d 1353, 1359 (Fed. Cir. 2011) 

(“[A] limitation that is added during prosecution to overcome prior art cannot be entirely eliminated on reissue . . . .”). We need not address step three, as the Khans 

have not argued that any of reissue claims 21, 29, 38, and 

39 are materially narrowed in other respects. 

On this analysis, we conclude that the reissue claims

impermissibly recapture subject matter surrendered 

during prosecution of the ’591 patent. Accordingly, we 

affirm the Board’s rejections of reissue claims 21–41 

under § 251. 

II

On an appeal to the Board, an appellant’s failure “to 

separately argue claims” within a group subject to a 

common ground of rejection “constitute[s] a waiver of any 

argument that the Board must consider the patentability 

of any grouped claim separately.” 37 C.F.R. 

§ 41.37(c)(1)(iv). 

Dependent claims 22, 24, 30, 40, and 41 are subject to 

a common rejection under § 251 of claims 21–41. Yet in 

their appeal to the Board, the Khans did not separately 

argue these dependent claims. The Khans cannot rely on 

passing references to these dependent claims made in 

their reply brief to the Board, as “[a] statement which 

merely points out what a claim recites will not be considered an argument for separate patentability of the claim.” 

37 C.F.R. § 41.37(c)(1)(iv). In such cases, we have found 

these arguments are waived. 

Accordingly, we find that the Board properly determined arguments regarding separate patentability of 

dependent claims 22, 24, 30, 40, and 41 have been waived. 

We have considered the Khans’ other arguments and find 

them without merit.
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CONCLUSION

Because we decide that reissue claims 21–41 impermissibly recapture subject matter surrendered during 

prosecution of the ’591 patent, we need not reach the

obviousness rejections. The judgment of the Board is 

affirmed.

AFFIRMED

COSTS

No costs.