(This article was originally published Wednesday.)
By Jennifer Corbett Dooren
WASHINGTON--The Food and Drug Administration on Wednesday
convened a two-day advisory panel meeting to discuss the safety of
metal hip implants, amid concerns there are more side effects than
with implants made out of such materials as ceramic or plastic.
The advisory panel is being asked to make recommendations
whether additional warnings and other information is needed for
metal hip systems, and to make recommendations about which types of
patients would benefit the most from metal implants as well those
who shouldn't get them. The panel is not being asked to discuss
regulatory changes like requiring the devices to go through more
stringent clinical testing.
In 2010, Johnson & Johnson's (JNJ) DePuy Orthopaedics Inc.
recalled 93,000 of its ASR total hip implants after they were
linked to higher failure rates than other implants. The ASR device
is no longer sold but is still implanted in many patients, and the
company faces about 6,000 lawsuits.
One of the safety concerns involves the wear on the implants and
its breaking down of the metal, which in some patients causes joint
and muscle destruction and other health problems.
Elizabeth Frank, an FDA medical reviewer, said Tuesday that
patients vary in their reactions to metal particulate, with some
having a severe inflammatory response to having no reaction.
Because hip implants were on the market before FDA started
regulating medical devices in 1976, such companies as DePuy and
Wright Medical Group Inc. (WMGI) only need to show a hip implant is
similar to a device already on the market and don't need to conduct
clinical studies showing safety and effectiveness, a process that
has been criticized by some policy makers and many patients.
Major changes to devices, however, do require additional
testing, and hip resurfacing systems, including ones made by Smith
& Nephew PLC (SNN), are required to go through FDA's premarket
approval process, which requires companies to conduct clinical
studies in humans looking at the devices' performance. The FDA said
other companies with metal hip implants on the market include
Biomet Inc., Zimmer Holdings Inc. (ZMH) and Encore Medical L.P.
There are about 400,000 hip implant surgeries in the U.S. each
year. About 25% of surgeries involve metal-on-metal implants,
according to recent U.S. government data.
Information from patient registries outside of the U.S. suggest
more patients need to have the metal implants fixed than other
types of implants. The U.S. doesn't have a national registry and
studies looking at implant failure rates in the U.S. have been
mixed. Some data suggest women have higher failure, or revision
rates, compared to men while other data suggests there might be
more problems with implants that have a larger component, called
the femoral head, than smaller components.
"Could it be the size of the head when we are attributing all
the problems to metal?" said Raj Rao, a panel member from the
orthopaedic surgery department of the Medical College of
Wisconsin.
Although the panel had not formally started addressing FDA's
questions Wednesday, preliminary discussion suggests the panel may
struggle to adopt clear recommendations given the number of
products and conflicting data.
"I don't believe the failure mechanism of these devices is the
same," said Edward Cheng, a panelist from the University of
Minnesota Medical School and Cancer Center.
Information prepared for the meeting by the FDA showed there's
been almost 17,000 adverse-event reports submitted to FDA involving
the metal-on-metal implants from 1992 through 2011. There were
22,000 for nonmetal hip implants. Of the metal-on-metal reports,
about 12,000 were submitted in 2011 with 9,000 attributed to the
DePuy ASR. The reports cited problems including the need for
revision--or additional surgery to fix or replace the
implant--pain, dislocation and bone infections.
In a presentation to the panel, Paul Voorhorst, the director for
biostatistics and data management for DePuy Orthopaedics, said not
all "metal-on-metal implants are the same and each should be
evaluated on its own merits." Mr. Voorhorst didn't specifically
mention the recalled ASR product and instead focused on another
product. However, he said the company believes all patients with
joint replacements need to be monitored.
-Write to Jennifer Corbett Dooren at jennifer.corbett@dowjones.com