United States Court of Appeals 

for the Federal Circuit 

__________________________ 

ENZO BIOCHEM, INC., ENZO LIFE SCIENCES, 

INC., 

AND YALE UNIVERSITY, 

Plaintiffs-Appellants, 

v. 

APPLERA CORP. AND TROPIX, INC., 

Defendants-Appellees. 

__________________________ 

2009-1281 

__________________________ 

Appeal from the United States District Court for the 

District of Connecticut in case no. 3:04-CV-929, 

Judge Janet Bond Arterton. 

__________________________ 

ON PETITION FOR PANEL REHEARING AND 

REHEARING EN BANC 

__________________________ 

Before MICHEL, Chief Judge, NEWMAN, MAYER, PLAGER,

∗

LOURIE, RADER, BRYSON, GAJARSA, LINN, DYK, PROST, and 

MOORE, Circuit Judges. 

PER CURIAM. 

 ∗

 Judge Plager participated only in the decision on 

the petition for panel rehearing. 

 
ENZO BIOCHEM v. APPLERA CORP 2

PLAGER, Circuit Judge, dissents from the denial of the 

petition for panel rehearing. 

__________________________ 

 NICHOLAS GROOMBRIDGE, Weil, Gotshal & Manges 

LLP, of New York, New York, filed a combined petition for 

panel rehearing and rehearing en banc for defendantsappellees. With him on the petition was JENNIFER H. WU. 

Of counsel on the petition was KURTIS D. MACFERRIN, Life 

Technologies Corporation, of Foster City, California. 

 L. GENE SPEARS, Baker Botts L.L.P., of Houston, 

Texas, filed a response to the petition for plaintiffsappellants. With him on the response was MICHAEL 

HAWES. 

__________________________ 

O R D E R 

Defendants-Appellees Applera Corp. and Tropix, Inc. 

filed a combined petition for panel rehearing and rehearing en banc. The panel requested a response from Plaintiffs-Appellants Enzo Biochem, Inc., Enzo Life Sciences, 

Inc., and Yale University. The court granted DefendantsAppellees leave to file a reply. The petition for rehearing 

was considered by the panel that heard the appeal, and 

thereafter the petition for rehearing en banc, the response 

to the petition, and reply were referred to the circuit 

judges who are in regular active service. 

Upon consideration thereof, 

IT IS ORDERED THAT: 

(1) The petition of Defendants-Appellees for panel 

 rehearing is denied. 

(2) The petition of Defendants-Appellees for rehearing en banc is denied. 
3 ENZO BIOCHEM v. APPLERA CORP

(3) The mandate of the court will issue on June 2, 

2010. 

FOR THE COURT

 May 26, 2010 

Date 

/s/ Jan Horbaly 

Jan Horbaly 

Clerk 

cc: L. Gene Spears, Esq. 

Nicholas Groombridge, Esq. 
United States Court of Appeals 

for the Federal Circuit 

__________________________ 

ENZO BIOCHEM, INC., ENZO LIFE SCIENCES, 

INC., 

and YALE UNIVERSITY, 

Plaintiffs-Appellants, 

v. 

APPLERA CORP. and TROPIX, INC., 

Defendants-Appellees. 

__________________________ 

2009-1281 

__________________________ 

Appeal from the United States District Court for the 

District of Connecticut in Case No. 3:04-CV-929, 

Judge Janet Bond Arterton. 

ON PETITION FOR PANEL REHEARING 

PLAGER, Circuit Judge, dissenting from the denial of 

the petition for panel rehearing. 

I respectfully dissent from the denial of the petition 

for panel rehearing on the question of indefiniteness. 

Despite the varying formulations that this court has used 

over the years in describing its “indefiniteness” jurisprudence to which the petitioner in this case points, the 

general conclusion from our law seems to be this: if a 

person of ordinary skill in the art can come up with a 

plausible meaning for a disputed claim term in a patent, 
ENZO BIOCHEM v. APPLERA CORP 2

that term, and therefore the claim, is not indefinite.1 At 

least not so indefinite as to run afoul of the statutory 

requirement that claims shall “particularly point[ ] out 

and distinctly claim[ ] the subject matter which the applicant regards as his invention.” 35 U.S.C. § 112, second 

paragraph. 

The corollary derived from this understanding is that 

if several persons of ordinary skill come up with competing but plausible interpretations of a disputed term—as is 

typically the case with competing “expert witnesses” in 

patent infringement litigation—the problem is not one of 

an inherently ambiguous and potentially indefinite claim 

term, but rather the problem becomes simply one of 

picking the “right” interpretation for that term.2 Since 

picking the “right” interpretation—claim construction—is 

a matter of law over which this court rules, and since the 

view of the trial judge hearing the case is given little 

 1 See, e.g., Datamize, LLC v. Plumtree Software, 

Inc., 417 F.3d 1342, 1347 (Fed. Cir. 2005) (“Only claims 

‘not amenable to construction’ or ‘insolubly ambiguous’ 

are indefinite.” (citing Novo Indus., L.P. v. Micro Molds 

Corp., 350 F.3d 1348, 1353 (Fed. Cir. 2003); Honeywell 

Int’l, Inc. v. Int’l Trade Comm’n, 341 F.3d 1332, 1338 

(Fed. Cir. 2003); Exxon Research & Eng’g Co. v. United 

States, 265 F.3d 1371, 1375 (Fed. Cir. 2001))). 

2 Broad, to the point of inherently ambiguous, claim 

drafting is not just a matter of poor drafting skills on the 

part of some lawyers who prosecute patent applications. 

On the contrary, the art of broad claim drafting is a 

prized talent—clients are openly urged to use “broad 

patent protection both offensively to block competitors 

from the marketplace, and defensively to serve as a 

bargaining chip against potential patent infringement 

suits” and to “file patents to cover all aspects of the core 

technology . . . to create a ‘picket fence’ of protection.” 

David J. Dykeman and Joanna T. Brougher, File, Protect, 

Update, Defend, Corporate Counsel, May 1, 2010, 

http://www.law.com/jsp/cc/PubArticleCC.jsp?id=12024476

71049. 
3 ENZO BIOCHEM v. APPLERA CORP

weight, so that the trial judge’s view on appeal becomes 

just a part of the cacophony before this court, it is not 

until three court of appeals judges randomly selected for 

that purpose pick the “right” interpretation that the 

public, not to mention the patentee and its competitors, 

know what the patent actually claims. The inefficiencies 

of this system, and its potential inequities, are well 

known in the trade. 

The United States Patent and Trademark Office 

(“PTO”), by contrast, appears to be taking steps to give 

the statutory requirement real meaning. In 2008, the 

patent examining corps was given a five-page instruction 

on “Indefiniteness rejections under 35 U.S.C. 112, second 

paragraph.”3 The memo initially observes that “[t]he 

primary purpose of the definiteness requirement for claim 

language is to ensure that the scope of the claims is clear 

so that the public is informed of the boundaries of what 

constitutes infringement of the patent.”4 The memo 

reviews in detail a recent opinion of this court, following 

which the memo states the position of the PTO: “If the 

language of a claim, considered as a whole in light of the 

specification and given its broadest reasonable interpretation, is such that a person of ordinary skill in the relevant 

art would read it with more than one reasonable interpretation then a rejection of the claim under 35 U.S.C. 112, 

second paragraph, is appropriate.”5 

This memo was followed later in the year by a rare 

precedential opinion issued by the Board of Patent Ap-

 3 Memorandum from John Love, Deputy Commissioner for 

Patent Examination Policy, to Technology Center Directors and 

Patent Examining Corps (Sept. 2, 2008), available at

http://www.uspto.gov/web/patents/memoranda.htm. 

4 Id. at 1. 

5 Id. at 2. 
ENZO BIOCHEM v. APPLERA CORP 4

peals and Interferences (“Board”) in Ex parte Miyazaki.6 

The Board noted that this court has in post-issuance 

patent infringement cases held “that the definiteness 

requirement ‘does not compel absolute clarity’ and ‘[o]nly 

claims “not amenable to construction” or “insolubly ambiguous” are indefinite.’”7 Recognizing that this court has 

never set forth a different standard of review for indefiniteness under 35 U.S.C. § 112, second paragraph, for 

pre-issuance pending claims as compared with postissuance patent claims,8 the Board concluded that the 

Federal Circuit’s reading of the indefiniteness requirement was counter to the PTO’s broader standard for claim 

construction during prosecution.9 Accordingly, the Board 

announced that, “rather than requiring that the claims 

are insolubly ambiguous, we hold that if a claim is amenable to two or more plausible claim constructions, the 

USPTO is justified in requiring the applicant to more 

precisely define the metes and bounds of the claimed 

invention by holding the claim unpatentable under 35 

U.S.C. § 112, second paragraph, as indefinite.”10

The Board is clearly right in recognizing that the circumstances are different between pre-issuance and postissuance application of the definiteness standard with 

regard to claim terms. At the same time, the PTO and 

the Board are clearly right in insisting that, if the public 

notice function of the patent law is to be honored, claim 

terms must particularly point out and distinctly claim the 

subject matter of the invention. In my view, this court’s 

definiteness doctrine could go considerably further in 

promoting that objective than it currently does, with the 

 6 No. 2007-3300, 2008 WL 5105055 (Bd. Pat. App. 

& Inter.) (Nov. 19, 2008). 

7 Id. at *4 (quoting Datamize, 417 F.3d at 1347). 

8 Id. at *6. 

9 Id. at *5. 

10 Id.
5 ENZO BIOCHEM v. APPLERA CORP

not inconsequential benefit of shifting the focus from 

litigation over claim construction to clarity in claim 

drafting. 

To begin the discussion of how this court could move 

in that direction, I would grant the petition for panel 

rehearing. The court now spends a substantial amount of 

judicial resources trying to make sense of unclear, overbroad, and sometimes incoherent claim terms. It is time 

for us to move beyond sticking our fingers in the neverending leaks in the dike that supposedly defines and 

figuratively surrounds a claimed invention. Instead, we 

might spend some time figuring out how to support the 

PTO in requiring that the walls surrounding the claimed 

invention be made of something other than quicksand. 

I respectfully dissent from the loss of that opportunity 

through the panel’s denial of rehearing.