Lynda Williams: Another disastrous
medical experiment
5:30 AM Thursday Apr 26, 2012 New
Zealand Herald (FiDA Blog bold added.)
Recent events have highlighted the
fact that neither the Ministry of Health nor any other government agency has
done anything about ensuring that medical devices used in New Zealand are fit
for purpose, have undergone clinical trials and are safe. This despite the fact
that several major scandals have made the headlines both here and
internationally over the past six months.
Through the media New Zealanders
have been made aware of the fact that medical devices such as breast implants,
the gynaecological mesh, and hip joint replacements can avoid having to undergo
clinical trials before they are marketed and sold as the best thing since
sliced bread.
The latest medical device to
dominate headlines around the world are two models of metal-on-metal hip joint
replacements. The first of these was the DePuy hip implant; the second is the
Mitch THR hip implant. The Ministry of Health and Medsafe remained quiet until
confronted by several major exposes in the NZ Herald in 2011 that led to light
bulbs going on in the heads of a number of New Zealanders who had had a hip
replacement. But nothing appeared on the Medsafe website.
As New Zealand patients struggled
to get information an article appeared in the February 2012 issue of the
British Medical Journal by investigations editor Deborah Cohen. It began:
Hundreds of thousands of patients around the world may have been exposed to
toxic substances after being implanted with poorly regulated and potentially
dangerous hip devices, a BMJ/BBC Newsnight investigation reveals this week.
Despite the fact that these risks have been known and well documented for
decades, patients have been kept in the dark about their participation in what has
effectively been a large uncontrolled experiment.
The metal-on-metal hip replacement
implants arrived on the scene in 1997. The head at the top and the lining of
the cup it fits into are made of cobalt-chromium alloy rather than ceramic or
polyethylene. Of course they were marketed as the latest advance in hip
replacement and were specifically targeted at younger patients who needed a hip replacement that would last their
life-time.
As the BMJ paper points out,
multiple studies and research organisations have warned about the carcinogenic
potential of metal-on-metal hips.
That cobalt and chromium ions lead to genotoxic changes, (changes that are
damaging to DNA and therefore capable of causing mutations or cancer), both in
laboratory settings and in animals was described in scientific journals over 30
years ago.
It comes as no surprise to learn
that the manufacturers were aware of the potential for genotoxicity. A DePuy
internal memo from July 2005 says: In addition to inducing potential changes in
immune function, there has been concern for some time that wear debris may be
carcinogenic. The mechanism is not known and only 24 local malignancies have
been reported in patients with joint replacements. Also worrying is the
possibility of distant effects. One study suggested a threefold risk of
lymphoma and leukaemia 10 years after joint replacement. The metal to metal
total hip appears to be quite promising and in the laboratory the data is (sic)
definitely in its favour. However, the ultimate test is the long term human
experience.
Rather than advising regulators and
patients of their concerns, companies tweaked the design of these devices.
The experiment continued, but only outside the USA. While the DePuy ASR products were approved by the
Australian Therapeutic Goods Administration in October 2003, they were not
cleared by the US Food and Drug Administration until January 2008. However, the
failure rates for total hip replacements were soon found to be higher than they
should be, and concerns began to be raised. In December 2009 DePuy withdrew the
ASR products from both the Australian and New Zealand markets.
In August 2010 DePuy contacted
Medsafe proposing to distribute a recall notice to all ASR trained surgeons in
New Zealand. Medsafe did not list the recall on its website, and nor
did it provide any information to patients about the problems associated with
metal-on-metal hip replacements.
When the Herald asked the Minister of Health about Medsafe's failure to list
the ASR recall on its website when other recalls were listed, Tony Ryall
replied As part of the new joint agreement with Australia, which comes into
effect July 1, I would expect such recalls to be listed on the joint website.
The fact that it hasn't reflects Medsafe's past practice and this will be
changing.
The rebuke from the Minister was
clearly enough to make Medsafe spring into immediate action. A comprehensive
timeline of events and documents leading up to the recall of ASR hip
replacements is now on their website. It tells a by now very familiar and
extremely depressing story.
When problems began to surface with
ASR hip joints and various committees in the UK met to discuss the issues, the
concerns were not made public and no alert was put out to surgeons or patients.
Another disturbing aspect to this was mentioned in the BMJ article which
referred to the fact that there were special risks for women of
child-bearing age due to the fact that metal ions had been detected in
umbilical cord and placental blood.
Neither the European nor the
American regulators picked up the high levels of metal ions produced by the
modified hip replacement devices when they came onto the market, as there
was no requirement for any post-approval studies that would follow-up patients implanted with devices
capable of producing toxic debris.
The BMJ paper ended with the
following conclusion: After a series of failures, device regulation is in need
of radical change. For its part, the FDA has decided
to place all hip implants into a high risk category fast track entry will be
forbidden".
In Europe there is little doubt the
current system is not fit for purpose and talks are underway about how to
improve it. As Professor Freemantle asks: Why is it that people are afforded different
levels of protection depending on whether they have a heart attack, diabetes,
or a hip replacement in their old age? The methods of device regulation
seem to be more from the 1950s than the 21st century.
Professor Freemantle's question is
a very good question indeed. Because New Zealanders who have had hip
replacements are unaware that they have been part of yet another disastrous
experiment, it is a question that needs an answer from both the Minister of
Health and the Health & Disability Commissioner.
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