From Bone Care Int’l LLC v. Pentech Pharmaceuticals, Inc., 2010 U.S. Dist. LEXIS 105118 (N.D. Ill. Oct. 1, 2010):

Plaintiffs *** submit that Mr. Sofocleous should be barred from testifying regarding the area in which they concede Mr. Sofocleous has professional experience: patent law. ***

The Court agrees that any testimony Mr. Sofocleous might seek to offer about his conclusions of law on issues in this case are excludable. Sommerfield v. City of Chicago, 254 F.R.D. 317, 330 (N.D. Ill. 2008) ("expert testimony that contains a legal conclusion that determines the outcome of a case is inadmissible"); Apotex Corp. v. Merck & Co., Inc., 2006 WL 1155954, at *8 (N.D. Ill. Apr. 25, 2006) (excluding expert testimony that consisted of "plainly inadmissible legal conclusions" that "would be completely unhelpful to the fact finder"); Clintec Nutrition Co. v. Baxa Corp., 1998 WL 560284, at *9 (N.D. Ill. Aug. 26, 1998) ("Legal conclusions are not admissible because they are not helpful to the trier of fact"). The critical issue for the parties, the Court, and the witnesses themselves to bear in mind is what the Seventh Circuit has described as the "difference between stating a legal conclusion and providing concrete information against which to measure abstract legal concepts." United States v. Blount, 502 F.3d 674, 680 (7th Cir. 2007). The former is prohibited; the latter is not. The Court also bars any testimony by Mr. Sofocleous that recites or explains patent law, including the requirements of patentability under the law. Bausch & Lomb, Inc., 79 F. Supp. 2d at 258; see also Amsted Indust., Inc. v. Nat'l Castings, Inc. , 1990 WL 106548, at *28 (N.D. Ill. Jul. 11, 1990) ("it would not be appropriate for [patent law expert] * * * to discuss the law governing patent validity). Plaintiffs' motion is thus granted to the extent that Mr. Sofocleous is barred from testifying to the substance, significance, or application of patent law.

[Footnote 8] "Rule 704 was not intended to allow experts to offer opinions embodying legal conclusions." Bausch & Lomb, Inc. v. Alcon Labs., Inc., 79 F. Supp. 2d 252, 255 (W.D.N.Y. 2000) (quoting United States v. Scop, 846 F.2d 135, 139 (2d Cir. 1988)); see also Se-Kure Controls, Inc. v. Diam USA, Inc., 2009 WL 77463, at *2 (N.D. Ill. Jan. 9, 2009) (concluding that proposed testimony of a patent expert on whether the patent at issue is enforceable, whether the patentee committed inequitable conduct, or the level of intent behind any alleged failures to disclose prior art was all inadmissible).

However, the Court concludes that Mr. Sofocleous's proposed testimony relating to the patent application process, the operations and functions of the PTO, and the criteria to which examiners look in assessing patentability (including obviousness, priority, etc.) are based in Mr. Sofocleous's specialized knowledge and touch on the core issues of the case. Although Plaintiffs complain that such testimony is needless since the proceedings of the patent are clear and easily understood on the face of the PTO records, the Court believes that such testimony would likely be helpful. See Bausch & Lomb, Inc., 79 F. Supp. 2d at 256 ("PTO procedures are foreign to the average person, and it may be helpful to the [trier of fact] to hear someone experienced in those procedures explain how they operate in terms that a layperson can understand").

The Court further finds that Mr. Sofocleous may opine on the priority filing date and other issues going to the validity of the '116 patent so long as he tethers his testimony to objective facts in the record. Thus, Mr. Sofocleous may provide factual context that goes to the underlying contentions of inequitable conduct, obviousness, priority, and other key legal issues, but he may not speculate or offer his subjective conclusions on those contentions. See Se-Kure Controls, Inc., 2009 WL 77463, at *2. Similarly, Mr. Sofocleous may offer any extant facts regarding acts or omissions in the applications giving rise to the '116 patent, but may not speculate as to the intent of the inventors or attorneys. See id. (holding that a patent expert is "not a mind-reader. He may not testify that he knows [patentee's] intent to hide certain information nor may he testify that he knows [patentee] lied about certain information"). In a similar vein, while Mr. Sofocleous may present testimony to the extent that he has a basis for opining on actual defects in the patent applications relating to the '116 patent, he will not be permitted to offer generalized testimony about potential memory problems of examiners or other non-case specific testimony "insinuating that the PTO does not do its job properly." Bausch & Lomb, Inc., 79 F. Supp. 2d at 255-56 (citing Applied Materials, Inc. v. Advanced Semiconductors Materials America, Inc., 1995 WL 261407, at *3 (N.D. Cal. Apr. 25, 1995)). With those caveats in mind, the Court denies Plaintiffs' motion in limine to the extent that it seeks to preclude Mr. Sofocleus from testifying as to factual matters relating to general PTO practice and procedure and the prosecution history of applications relating to the '116 patent.