Judge Forrest finds patentee’s claim constructions to be overly broad, and lacking specification support

Regeneron Pharm., Inc. v. Merus B.V.

Case Number: 1:14-cv-01650-KBF

On March 14, 2014 Regeneron Pharmaceuticals, Inc. (“Regeneron”) commenced this action against Merus B.V. (“Merus”) and Ablexis LLC (“Ablexis”) alleging infringement of U.S. Patent No. 8,502,018 (“‘018 Patent”) (titled “Methods of Modifying Eukaryotic Cells”).  On July 3, 2014, defendants answered the complaint asserting invalidity and non-infringement, among other defenses.  Prior to the issuance of this claim construction order, defendant Ablexis settled.

Judge Forrest construed seven terms of the ‘018 Patent.  Before diving into her analysis, the writing was already on the wall against the plaintiff.  First, Judge Forrest wrote that the patent, construed as plaintiff contended, posited a patent with extraordinarily broad reach.  Second, Judge Forrest noted that, despite opining that each of the disputed terms were unambiguous and would be well known to POSITA, plaintiff’s expert failed to review any of the ‘018 Patent’s prosecution history.  Third, after a brief introduction to her Opinion & Order, Judge Forrest wrote:

Given the resources allocated to, and diverse outcomes of claim construction proceedings, it is plain that patent holders are frequently mistaken as to the nature and scope of their invention.  While they believe (or assert) that they hold a patent disclosing one invention, claim construction may reveal quite another invention altogether.  If a patent holder’s view is overly broad, such position may reveal wishful thinking or short-sightedness during prosecution; no matter, claim construction reveals actual metes and bounds.

(Emphasis added.)

Here, Plaintiff Regeneron asserted that the ‘018 Patent covered “a mouse modified to include a human DNA sequence at the immunoglobulin locus, leaving the mouse constant regions intact.”  In other words, the patentee invented “a mouse which can be genetically modified using any number of available methods, involving the insertion of a human or synthetic gene segment somehow at or near the immunoglobulin locus.”

In stark contrast, defendant Merus asserted that the ‘018 Patent disclosed a narrow invention “ultimately bounded by the particular method for genetically modifying a mouse with which the Specification is principally concerned.”  Further, “[m]ice genetically modified in any number of different manners – but which ultimately share a similar genetic profile – are, according to Merus, outside of the Patent’s scope.”

This difference in scope of the parties’ proposed constructions – plaintiff’s broad interpretation versus defendant’s narrow one – is at the heart of each disputed term.  Unsurprisingly, in construing the terms based on limitations disclosed in the specification, Judge Forrest generally agreed with the constructions proposed by Merus, “limiting the Patent to a far narrower scope than that asserted by Regeneron.”

The following table lists the disputed terms and Judge Forrest’s construction of the terms.

Disputed Term

Court’s Claim Construction

“A genetically modified mouse”

Merus asserted that said term should be construed as “A transgenic mouse produced by the process of using LTVECs to modify embryonic stem cells and using a quantitative assay to detect modification of allele in those cells.” 

(Court agreed with Merus’s proposed construction.)

“human unrearranged variable region gene segments”

Merus asserted that said term should be construed as “A contiguous stretch of cloned human genomic DNA containing variable region gene segments (V, D and J for the heavy chain / V and J for the light chain) in germline configuration, i.e. as it is in the human genome before the development of B cells.”

(Court agreed with Merus’s proposed construction.)


Merus asserted that said term should be construed as “One step addition of DNA, without replacing or deleting any native DNA as a result of the addition.”

(Court agreed with Merus’s proposed construction.)


Merus asserted that said term should be construed as “Into the locus, as opposed to near the locus, by the locus or around the locus.”

(Court agreed with Merus’s proposed construction.)

“endogenous mouse immunoglobulin locus”

Merus asserted that said term was indefinite.

(Court agreed with Merus that as of 2001 there is clear and convincing evidence that the metes and bounds of the locus were not identified with reasonable certainty; the scope of the term also lacked reasonable certainty and was therefore indefinite.)

“linked” and “operably linked”

Merus asserted that the term “linked” should be construed as “covalently bonded”, and that the term “operably linked” should be construed as “covalently bonded such that the rearranged human variable region causes the expression of the mouse constant region gene.”

(Court agreed with Merus’s proposed construction.)

“does not comprise a human immunoglobulin constant gene” and “lacks a human constant region gene”

Merus asserted that both said terms should be construed as “The mouse lacks DNA that regulates or encodes a constant region gene that originates from a human (i.e., genomic).”  or is in human sequence.”

(Court generally agreed with Merus’s proposed construction, by deleting the stricken language and adding the underlined language.)

See Related Articles:

Form 18 of the Federal Rules of Civil Procedure Rejected as an “Off-Ramp” to Twombly

Judge Forrest: “Regeneron's position that each claim in its ‘018 Patent has a single limitation is, at the very least, odd. It is also possibly a colossal tactical blunder.

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