United States District Court, D. Arizona
IN RE Bard IVC Filters Products Liability Litigation,
G. CAMPBELL, UNITED STATES DISTRICT JUDGE.
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
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.
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.
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.
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”). 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, ).
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.
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. 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
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
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).
Assumptions About Adverse Event Reporting.
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 ...