: A Forum for
Communicating Outside the Box
Estelle Russek-Cohen, CDRH Division of Biostatistics, FDA, and Jeng Mah, American Medical Systems
I
n 2005, statisticians from the Medical Device and Diagnostics Medical device trials cannot always be blinded. When evaluating
Industry and the U.S. Food and Drug Administration’s Center for an artificial hip replacement or a drug eluting stent, sham surger-
Devices and Radiological Health (CDRH) decided it would be ies are unethical. So, sponsors sometimes rely on historical control
useful to have a means of communicating outside the formal regula- data, rather than the usual randomized study designs. Therefore, one
tory environment and to talk about issues common to both groups. has the challenge of deciding whether the historical control data is a
The statisticians met for the first time as a group and worked toward legitimate comparator and must consider methods such as propensity
creating SIGMEDD, the Special Interest Group in Medical Devices score analyses.
and Diagnostics. Devices often have software, and hardware components and mod-
What exactly is a medical device? In the FDA organization, cen- ifications are inevitable. Rather than go back to square one, companies
ters take primary responsibility for certain categories of products. may elect to use information from their own previous submissions via
The Center for Food Safety and Applied Nutrition (CFSAN) is a Bayesian framework. This involves statisticians from the FDA and a
responsible for issues concerning food safety. The National Center company designing studies together.
for Toxicological Research (NCTR) engages in research associated We are in an age of advanced imaging systems such as computer-
with toxicology. The Center for Veterinary Medicine is responsible ized tomography and digital mammography. There is computer-aided
for drugs used to treat farm and companion animals. diagnostic software that provides aid to a radiologist. When one wants
Three centers are responsible for products associated with the care to understand if the software or the image, itself, helps the reader
of people. The Center for Drug Evaluation and Research (CDER) get more accurate assessments of patients, the study designs and data
regulates the approval of drugs. The Center for Biologic Evaluation analysis evaluation become interesting because one wants to study the
and Research (CBER) regulates the approval of vaccines, blood impact of the reader in the loop.
products, and therapies such as gene therapy and immunotherapies. Personalized medicine sounds great, but it presents major statis-
CDRH regulates “everything else,” including orthopedic and cardio- tical challenges. CDRH, in partnership with CDER and CBER,
vascular implants, surgical instruments of all shapes and sizes, and reviews diagnostic devices that may predict which treatment is best
diagnostic devices. for a patient. There is now an evolving literature on the role of prog-
A medical device is any medical product (i.e., a product that nostic and predictive markers, and SIGMEDD provides a forum for
makes a medical claim) whose mechanism of action is not chemical statisticians to engage in developing solutions.
or biological. Medical devices include artificial prostheses, pacemak- In contrast to academia, the focus is on methodology that may
ers, hearing aids, surgical instruments, diagnostic imaging systems, help a company bring a novel product to market. SIGMEDD allows
and in vitro diagnostic devices, as well as software that may drive for an open discussion of statistical issues without discussions of a spe-
medical decisionmaking. cific product. However, academics with an interest in research ques-
The principles in evaluating and regulating new devices and drugs tions raised in this area are most welcome to attend.
are similar, but the practices are somewhat different to categorize the For several years, many SIGMEDD members have worked togeth-
range of variations. Devices are categorized by their intended use, and er to create topic-contributed sessions at the Joint Statistical Meetings.
those with the highest risk are submitted under a pre-market approval, 2008 is no exception. In Denver, we have seven topic-contributed ses-
or PMA. Devices with a lower risk based on their intended use may sions, including Statistical Issues in Biomarker and Imaging Studies,
come in under a 510(k), named for the legislation that created the Assessing Bias in Pre-Clinical and Clinical Diagnostic Studies,
category. The 510(k) paradigm for clearing many “me too” medical Statistical Issues in Medical Device Studies, Study Design Issues in
devices has issues analogous to establishing bioequivalence in the drug Medical Device Clinical Trials, Statistics in Ophthalmology Clinical
world. But, medical devices have some clearly different aspects. Trials, Bayesian Issues in Medical Devices, and Data Analysis Issues
The special interest group brings together statisticians involved in in Medical Device Trials. As in the past, the Biopharmaceutical,
the design, development, and evaluation of medical devices. This gen- Statistics in Epidemiology, and Bayesian Statistical Sciences sections
erally means lots of interesting statistical challenges. have offered to be primary sponsors for these sessions.
Many therapeutic devices are studied under randomized clinical SIGMEDD also will have its annual meeting at JSM in Denver
trials, and we have many of the same statistical issues our colleagues in this year. Anyone interested in medical devices and diagnostics is wel-
drug development have: missing data, compliance, and messy time- come to join us. The meeting is August 4 at 5 p.m. Check out the
to-event data. There is an interest in surrogate endpoints, too. Tools online program at www.amstat.org/meetings/jsm/2008/onlineprogram
that assist a surgeon or a new tool to assist with interpretation of an for the room number.
image may require training and skill. We worry about treatment by For details and updates about the activities of SIGMEDD, visit
center interactions and learning curves during the study. www.amstat.org/sections/sigmedd. ■
MAY 2008 AMSTAT NEWS 29
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