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In re Bard IVC Filters Products Liability Litigation

United States District Court, D. Arizona

January 22, 2018

IN RE Bard IVC Filters Products Liability Litigation,



         This multidistrict litigation (“MDL”) involves thousands of personal injury cases related to inferior vena cava (“IVC”) filters manufactured and marketed by Defendants C. R. Bard, Inc. and Bard Peripheral Vascular, Inc. (collectively, “Bard”). Bard has filed a motion to exclude the opinions of Rebecca Betensky, Ph.D. Doc. 7288. The motion is fully briefed, and the Court heard arguments on January 19, 2018. The Court will deny the motion.

         I. Background.

         The IVC is a large vein that returns blood to the heart from the lower body. IVC filters are small metal devices implanted in the IVC to catch blood clots before they reach the heart and lungs. IVC filters, such as Bard's Simon Nitinol Filter (“SNF”), originally were designed to be implanted permanently. Because some patients need only temporary filters, however, medical device manufacturers such as Bard developed retrievable filters. Bard first marketed a retrievable filter in 2003. Seven different versions of Bard retrievable filters are at issue in this MDL - the Recovery, G2, G2 Express, G2X, Eclipse, Meridian, and Denali.

         Each Plaintiff in this MDL was implanted with a Bard retrievable filter and claims it is defective and has caused serious injury or death. Plaintiffs allege that the filters tilt, perforate the IVC, or fracture and migrate to neighboring organs. Plaintiffs claim that Bard filters are more dangerous than other IVC filters, and that Bard failed to warn about the higher risks. Plaintiffs assert a host of state law claims, including manufacturing and design defects, failure to warn, breach of warranty, and consumer fraud and unfair trade practices. Doc. 303-1. Bard disputes Plaintiffs' allegations, contending that overall complication rates for Bard filters are comparable to those of other IVC filters and that the medical community is aware of the risks associated with IVC filters.

         Plaintiffs have identified Dr. Betensky, a biostatistician, as an expert witness regarding risk rates associated with Bard filters. Dr. Betensky is the director of biostatistics programs at Massachusetts General Hospital and Harvard University. She is a faculty member at the Harvard-MIT Division of Health Sciences and Technology, has taught courses in biostatistics at Harvard School of Public Health, and has authored more than 200 peer-reviewed articles related to biostatistics. See Doc. 7818 at 4 n.4.

         In this MDL, Dr. Betensky opines generally that there is a higher risk of adverse events for Bard's retrievable IVC filters than for its permanent SNF. Doc. 7290. Dr. Betensky relied on sales information provided by Bard and adverse event reports extracted from the MAUDE database maintained by the Food and Drug Administration (“FDA”).[1] Dr. Betensky compared, over multiple time periods, the proportion of adverse event reports for each Bard retrievable filter relative to sales, to the proportion of adverse event reports for the SNF over sales. Id. at 2. She calculated a “reporting risk ratio” (“RRR”) as the ratio of the reporting risk for each retrievable filter to that of the SNF, using this equation: RRR = (x, /n, )/(x, /n, ). [2] The RRR is then used as an estimate of the actual risk ratio (“RR”) for the various filters. An RRR value larger than 1 suggests a higher RR for the retrievable filters than for the SNF. Id. at 4. Dr. Betensky found that for each Bard retrievable filter, there were statistically significant increased RRRs for adverse events such as death due to filter embolization and filter fracture, migration, perforation, or tilt. Id. at 3, 8-12, 15.

         Defendants challenge Dr. Betensky's opinions on several grounds. Defendants contend that she applied unfounded assumptions in her calculations, resulting in biased opinions that may not reflect an actual increased risk for retrievable filters. Defendants further contend that the opinions are flawed because Dr. Betensky failed to consider potential adverse events from the first ten years the SNF was on the market, or rule out alternative explanations for the increased risk she estimated. Finally, Defendants contend that the opinions are based solely on an improper comparison of anecdotal adverse event reports contrary to express guidance from the FDA. Doc. 7288 at 2.[3] Plaintiffs oppose the motion, arguing that Dr. Betensky is a highly-qualified expert who considered all available data and used a reliable methodology to form her opinions. Doc. 7818. For reasons stated below, the Court finds that Defendants' criticisms, to the extent valid, go the weight to be afforded the opinions, not their admissibility.

         II. Legal Standard.

         Under Rule 702, a qualified expert may testify on the basis of “scientific, technical, or other specialized knowledge” if it “will assist the trier of fact to understand the evidence, ” provided the testimony rests on “sufficient facts or data” and “reliable principles and methods, ” and “the witness has reliably applied the principles and methods to the facts of the case.” Fed.R.Evid. 702(a)-(d). An expert may be qualified to testify based on his or her “knowledge, skill, experience, training, or education.” Id.

         The proponent of expert testimony has the ultimate burden of showing that the expert is qualified and the proposed testimony is admissible under Rule 702. See Lust v. Merrell Dow Pharm., Inc., 89 F.3d 594, 598 (9th Cir. 1996). The trial court acts as a gatekeeper to assure that expert testimony “both rests on a reliable foundation and is relevant to the task at hand.” Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579, 597 (1993). Rule 702's requirements, and the court's gatekeeping role, apply to all expert testimony, not only to scientific testimony. Kumho Tire Co. v. Carmichael, 526 U.S. 137, 147 (1999).

         III. Discussion.

         A. Assumptions About Adverse Event Reporting.

         Dr. Betensky's expert report acknowledges and discusses potential limitations in her analysis. Doc. 7290 at 12-14. These include the possibility that adverse events were underreported for one or more of the devices at issue. Dr. Betensky found that while the RRRs she calculated may involve some degree of underreporting, which makes them “imperfect estimates of the actual risk ratios, ” there is strong evidence that actual risk ...

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