The opinion of the court was delivered by: DuBOIS, J.
Plaintiff Kiley Wolfe alleges in this action that Children's Motrin*fn1 manufactured and marketed by defendants caused her to develop serious, life-altering illnesses. Presently before the Court are nine Daubert*fn2 motions -- three filed by plaintiff and six by defendants -- to exclude or limit the proposed testimony of a total of eleven proposed expert witnesses. For the reasons that follow, the Court denies four of defendants' motions and all three of plaintiffs' motions. The remaining two motions -- defendants' motion to exclude the testimony of Drs. Laura Bix and Marvin Goldberg and their motion to exclude the testimony of Dr. George M. Samaras -- are granted in part and denied in part.
By Memorandum and Order of March 30, 2011, the Court denied defendants' motion for summary judgment as to plaintiff's failure-to-warn claims and claim for punitive damages and granted the motion in all other respects. Wolfe v. McNeil-PPC, Inc., --- F. Supp. 2d ---, 2011 WL 1157927, at *12 (E.D. Pa. Mar. 30, 2011). The factual background of the case is set forth in the Memorandum of March 30, 2011, and will not be repeated in this Memorandum except as is necessary to explain the Court's rulings.
III. LEGAL STANDARD -- FEDERAL RULE OF EVIDENCE 702
Federal Rule of Evidence ("Rule") 702 provides as follows:
If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise, if (1) the testimony is based upon sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case.
The "pathmarking" Supreme Court cases interpreting Rule 702 are Daubert v. Merrell Dow Pharm., 509 U.S. 579 (1993), and Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999). United States v. Mitchell, 365 F.3d 215, 234 (3d Cir. 2004). In Daubert, the Supreme Court held that "[f]aced with a proffer of expert scientific testimony . . . the trial judge must determine at the outset . . . whether the expert is proposing to testify to (1) scientific knowledge that (2) will assist the trier of fact to understand or determine a fact in issue." Daubert, 509 U.S. at 592. In Kumho Tire, the Supreme Court made clear that the Daubert gatekeeping function extends beyond scientific testimony to testimony based on "technical" and "other specialized" knowledge. 526 U.S. at 141.
Under Daubert, courts must address a "trilogy of restrictions" before permitting the admission of expert testimony: qualification, reliability and fit. Schneider ex rel. Est. of Schneider v. Fried, 320 F.3d 396, 404 (3d Cir. 2003); see also Elcock v. Kmart Corp., 233 F.3d 734, 741 (3d Cir. 2000). The party offering the expert must prove each of these requirements by a preponderance of the evidence. In re TMI Litig., 193 F.3d 613, 663 (3d Cir. 1999).
To qualify as an expert, "Rule 702 requires the witness to have 'specialized knowledge' regarding the area of testimony." Betterbox Commc'ns Ltd. v. BB Techs., Inc., 300 F.3d 325, 335 (3d Cir. 2002) (quoting Waldorf v. Shuta, 142 F.3d 601, 625 (3d Cir. 1998)). The Third Circuit has instructed courts to interpret the qualification requirement "liberally" and not to insist on a certain kind of degree or background when evaluating the qualifications of an expert. See Waldorf, 142 F.3d at 625. "The language of Rule 702 and the accompanying advisory committee notes make clear that various kinds of 'knowledge, skill, experience, training, or education,' qualify an expert as such." In re Paoli R.R. Yard PCB Litig., 916 F.2d 829, 855 (3d Cir. 1990) (quoting Fed. R. Evid. 702) ("Paoli I").
Moreover, "[t]his liberal policy of admissibility extends to the substantive as well as the formal qualifications of experts." Pineda v. Ford Motor Co., 520 F.3d 237, 244 (3d Cir. 2008). Thus, "it is an abuse of discretion to exclude testimony simply because the trial court does not deem the proposed expert to be the best qualified or because the proposed expert does not have the specialization that the court considers most appropriate." Id. (quoting Holbrook v. Lykes Bros. S.S. Co., 80 F.3d 777, 782 (3d Cir.1996)).
The reliability requirement of Daubert "means that the expert's opinion must be based on the 'methods and procedures of science' rather than on 'subjective belief or unsupported speculation'; the expert must have 'good grounds' for his or her belief." In re Paoli R.R. Yard PCB Litig., 35 F.3d 717, 742 (3d Cir. 1994) ("Paoli II") (quoting Daubert, 509 U.S. at 590). In Kumho Tire, the Supreme Court held that the Daubert test of reliability is "flexible" and that "the law grants a district court the same broad latitude when it decides how to determine reliability as it enjoys in respect to its ultimate reliability determination." 526 U.S. at 141-42 (emphasis omitted). In determining whether the reliability requirement is met, courts examine the following factors where appropriate:
(1) whether a method consists of a testable hypothesis; (2) whether the method has been subject to peer review; (3) the known or potential rate of error; (4) the existence and maintenance of standards controlling the technique's operation; (5) whether the method is generally accepted; (6) the relationship of the technique to methods which have been established to be reliable; (7) the qualifications of the expert witness testifying based on the methodology; and (8) the non-judicial uses to which the method has been put.
Mitchell, 365 F.3d at 235 (citing Paoli II, 35 F.3d at 742 n.8). These factors are neither exhaustive nor applicable in every case. Kannankeril v. Terminix Int'l, Inc., 128 F.3d 802, 806-07 (3d Cir. 1997).
Under the Daubert reliability prong, parties "do not have to demonstrate to the judge by a preponderance of the evidence that the assessments of their experts are correct, they only have to demonstrate by a preponderance of evidence that their opinions are reliable." Paoli II, 35 F.3d at 744 (emphasis omitted). "The evidentiary requirement of reliability is lower than the merits standard of correctness." Id. "As long as an expert's scientific testimony rests upon 'good grounds, based on what is known,' it should be tested by the adversary process -- competing expert testimony and active cross-examination -- rather than excluded from jurors' scrutiny for fear that they will not grasp its complexities or satisfactorily weigh its inadequacies." Mitchell, 365 F.3d at 244 (quoting Ruiz-Troche v. Pepsi Cola of P.R. Bottling Co., 161 F.3d 77, 85 (1st Cir.1998)).
For expert testimony to meet the Daubert "fit" requirement, it must "assist the trier of fact to understand the evidence or to determine a fact in issue." Fed. R. Evid. 702. "This condition goes primarily to relevance. Expert testimony which does not relate to any issue in the case is not relevant and, ergo, non-helpful." Daubert, 509 U.S. at 591 (citations and internal quotation marks omitted). "'Fit' is not always obvious, and scientific validity for one purpose is not necessarily scientific validity for other, unrelated purposes." Id.
IV. DEFENDANTS' DAUBERT MOTIONS
With those standards in mind, the Court turns first to defendants' Daubert motions. Defendants have filed six motions addressing the proposed testimony of eight experts. The Court will address each motion in turn.
A. Motions to Exclude Testimony of Drs. Moshe Arditi, Talal Chatila and Philip Rosenthal*fn3 Defendants seek to exclude the testimony of three of plaintiff's proposed causation experts: Dr. Moshe Arditi, Dr. Talal Chatila and Dr. Philip Rosenthal. The Court concludes that all three experts are qualified under Daubert and Rule 702 and denies defendants' motions.
Dr. Arditi is the Director of Pediatric Infectious Diseases and
Immunology at Cedars Sinai Medical Center in Los Angeles. He also
practices at Cedars Sinai and is a professor of pediatrics at the
University of California, Los Angeles ("UCLA"). His proposed testimony
is that the testing performed on plaintiff that failed to find a viral
or bacterial cause for her Stevens-Johnson Syndrome ("SJS")*fn4
was "very systematic" and "thorough." (Arditi Report at 4.)
Based on this opinion, he concludes "to a reasonable degree of medical
certainty" that plaintiff's SJS with Vanishing Bile Duct Syndrome
("VBDS")*fn5 was not caused by a viral or bacterial
infection but was instead "most likely drug-induced." (Id.)
Dr. Chatila, like Dr. Arditi, is a professor of pediatrics at UCLA. He heads the Division of Pediatric Immunology, Allergy and Rheumatology at that school. He is prepared to testify, "to a reasonable degree of medical certainty," that plaintiff's SJS and VBDS were caused by the Children's Motrin she ingested. (Chatila Report at 4.)
Dr. Rosenthal is the Director of Pediatric Hepatology and the Medical Director of the Pediatric Liver Transplant Program at the University of California, San Francisco. He has opined that plaintiff developed SJS and VBDS (leading to a liver transplant) because she took ibuprofen.
The defendants challenge the qualifications of these three experts and the reliability of their methodology. The Court finds defendants' arguments unpersuasive.
As noted above, Dr. Arditi practices medicine at Cedars Sinai in Los Angeles. He specializes in pediatric infectious diseases and is a professor of pediatrics at UCLA. He has authored more than 80 peer-reviewed articles, which have been published in such journals as the New England Journal of Medicine and Pediatrics. (See Pl.'s Opp'n to Defs.' Mot. to Exclude Arditi, Ex. C.) He has treated "many" patients with SJS and related ailments. (Arditi Dep. at 21.)
Dr. Chatila's work focuses on immunological and allergic diseases. (Chatila Report at 1.) He has authored more than 100 peer-reviewed articles, which have been published in an array of reputable professional journals. (See Pl.'s Opp'n to Defs.' Mot. to Exclude Chatila, Ex. E.) Over the course of his career, he has helped care for patients with SJS and related illnesses. (Chatila Dep. at 29.)
Dr. Rosenthal has 30 years' experience as "an actively practicing pediatric gastroenterologist." (Rosenthal Report at 1.) He has published more than 100 peer-reviewed journal articles. (See Pl.'s Opp'n to Defs.' Mot. to Exclude Rosenthal, Ex. E.) He has helped treat three patients with SJS over the course of his career. (Id., Ex. B at 14-16.) He has seen "lots" of patients with liver disease. (Id., Ex. E at 28.)
Defendants contend that Dr. Arditi is not qualified to opine on the cause of plaintiff's SJS and VBDS because he is "self-admittedly not an SJS expert" and "not an expert in the liver or diseases of the liver." (Defs.' Mot. to Exclude Arditi at 8-9.) They argue that Dr. Chatila is not qualified to opine on the cause of plaintiff's SJS and VBDS because he has never published work on SJS or drug reactions, never in his practice determined the cause of a patient's SJS and is not an expert on liver disease. (Defs.' Mot. to Exclude Chatila at 8, 11.) Finally, they assert that Dr. Rosenthal is not qualified to opine on the cause of plaintiff's SJS and VBDS because he has never determined the cause of a plaintiff's SJS, admits he is not an expert in SJS, has never published any work regarding SJS and has never treated a patient who had both liver disease and SJS. (Id. at 5-6, 8-9.)
Under Daubert, however, an expert's base of knowledge need not be as specialized as defendants urge. As the Third Circuit has held, "it is an abuse of discretion to exclude testimony simply because the trial court does not deem the proposed expert to be the best qualified or because the proposed expert does not have the specialization that the court considers most appropriate." Pineda, 520 F.3d at 244 (quoting Holbrook, 80 F.3d at 782). That Dr. Arditi has never conducted his own research on the causes of SJS or VBDS and does not consider himself an expert in the two diseases "goes to credibility and weight, not admissibility." Id. The same analysis applies to the claimed deficiencies in the qualifications of Drs. Chatila and Rosenthal. In sum, the three doctors satisfy Daubert's "liberal" qualifications standard.
In reaching his conclusions, Dr. Arditi reviewed a panoply of records from this case, as well as several articles that discuss the relationship among ibuprofen, SJS and VBDS. He concluded that the tests performed on plaintiff ruled out known viral or bacterial causes and that, therefore, her ailments were most likely drug-induced. This method of determining causation based on a process of elimination of other potential causes is known as a differential diagnosis. See Stedman's Medical Dictionary 531 (28th ed. 2006). Drs. Rosenthal and Chatila also performed differential diagnoses. A proper differential diagnosis is a reliable scientific method under Daubert. See Heller v. Shaw Indus., Inc., 167 F.3d 146, 154-55 (3d Cir. 1999). That is so even where the expert never performed a physical examination of the injured party. Kannankeril, 128 F.3d at 807.
Defendants assert that the three doctors' methodology is unreliable because (1) they did not rule out all potential viruses -- for example, because there are unknown viruses and viruses for which no tests are available -- and (2) the literature they reviewed on SJS and VBDS consisted primarily of only two or three case reports. Neither argument is persuasive.
First, in performing a differential diagnosis, an expert is only required to rule out "[o]bvious alternative causes." Heller, 167 F.3d at 156 (citation omitted). "A medical expert's causation conclusion should not be excluded because he or she has failed to rule out every possible alternative cause of plaintiff's illness." Id. Defendants will, of course, be able to cross-examine the three doctors about potential causes they did not exclude. But their inability to rule out all possible causes before rendering their diagnoses does not render their opinions unreliable under Daubert.
Second, case studies are reports of clinical events involving only one or a few people. Reference Manual on Scientific Evidence 474 (2d ed. 2000). Because they lack the controls of more rigorous studies, such reports "must be regarded with caution." Id. at 475. However, "such studies may be carefully considered in light of other information available." Id.; see Heller, 167 F.3d at 154 ("[W]e do not believe that Daubert . . . require[s] a physician to rely on definitive published studies before concluding that exposure to a particular object or chemical was the most likely cause of a plaintiff's illness."); Deutsch v. Novartis Pharm. Corp., --- F. Supp. 2d ---, 2011 WL 790702, at *54 (E.D.N.Y. Mar. 8, 2011) ("Even if case reports on their own are not reliable evidence of causation, they do contribute to the reliability of a causation determination.").
In this case, the three doctors did not solely rely on case reports in forming their opinions on causation but used them to supplement their extensive review of plaintiff's medical records and deposition testimony of plaintiff's treating physicians. As with defendants' other objections, the three doctors' use of case studies in reaching their conclusion affects only the weight to be given their testimony, not its admissibility. Thus, the proposed testimony of the three doctors is based on sufficiently reliable methods.
The three doctors' testimony clearly will help the trier of fact determine a fact in issue. The testimony addresses one of the central issues in the case: whether the ingestion of Children's Motrin caused plaintiff to develop SJS and VBDS. Thus, the three ...