FDA Panel Discussing Safety of Metal-On-Metal Hip Implants
Published
June 27, 2012
Dow
Jones Newswires
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.
Read
more: http://www.foxbusiness.com/news/2012/06/27/fda-panel-discussing-safety-metal-on-metal-hip-implants/#ixzz1z3LUiUKx LINK
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