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 The views highlight a significant new hurdle to
wider approval and acceptance of the therapy, known as renal
denervation, which had raised hopes in the medical community as a
way to treat stubbornly high blood pressure for patients who don't
gain enough benefit from drugs.
Wall Street analysts had estimated a potential market of $3 billion
for the devices made by Medtronic Inc, Boston Scientific Corp and St
Jude Medical Inc. But failure of the high-stakes clinical trial set
off a heated debate between doctors who believe the approach is
worth saving and those who say results show it provides no clear
benefit.
Trial data presented at the American College of Cardiology (ACC)
annual meeting last week showed that Medtronic's Symplicity renal
denervation device failed to lower blood pressure any more than a
fake procedure in a closely watched 364-patient study, calling into
question the therapy approved in more than 80 countries.
The devices are not approved in the United States.
"I think sales should be suspended," said Dr. Steven Nissen, head of
cardiology at the Cleveland Clinic, referring to the entire class of
devices. "You (now) have a trial with no evidence it works," he told
Reuters.
Dr. P.K. Shah, another prominent cardiologist from Cedars-Sinai
Medical Center in Los Angeles and professor of medicine at UCLA,
agreed that a suspension of sales might be prudent.
"European colleagues would be better off doing the right clinical
trials and perhaps putting a short-term moratorium on making (them)
available, except to participate in a clinical trial," Shah said.
The Symplicity trial was the first to subject one group of patients
to a sham procedure — during which they were sedated and had a
catheter threaded into their arteries but no actual treatment — to
account for any potential placebo effect. Prior informal trials of
the devices with no control group had shown average systolic blood
pressure reductions of twice what was seen in the latest Symplicity
trial.
Some cardiologists, including Dr. John Burnett of the Mayo Clinic in
Rochester, Minnesota, and ACC President Dr. Patrick O'Gara, said a
formal review of the products should be undertaken.
"A few patients seem to have derived benefit from this type of
intervention. We need to convene a group of experts to weigh the
positives and negatives of a moratorium," said O'Gara of Brigham and
Women's Hospital in Boston.
The European Society of Hypertension recommended "further studies of
high scientific caliber" on renal denervation's relative benefits.
Many of the doctors interviewed by Reuters noted potential flaws in
the Symplicity trial results, including questions over whether the
trial procedures were done correctly.
Medtronic, in an emailed statement, said the trial did not prove
renal denervation does not work. It will continue to sell the device
where approved and study its effectiveness.
"Medtronic believes physicians should make clinical decisions based
on the totality of evidence, including their own independent
experience," it said.
THE KIDNEY CONNECTION
The renal denervation procedure involves inserting the device
through the groin and threading it to the kidney via a catheter. It
then applies radiofrequency pulses to the renal arteries to damage
nerve endings in the vascular wall that doctors believe contribute
to blood pressure elevation.
The therapy has been available for years in Europe, where medical
devices must only prove their safety to the satisfaction of one of
dozens of regulator bodies to gain approval. Effectiveness is
determined through post-approval surveillance.
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Many doctors are hopeful the therapy will ultimately succeed
based on results of animal studies and previous trials. But Wall
Street's predictions of multibillion-dollar sales within 10 years
for the renal denervation market now seem unattainable, since they
depended on U.S. approval.
"This certainly set the field back several years," Jefferies & Co
analyst Raj Denhoy said of the failed study. "There are no prospects
of a device getting approved in the United States anytime soon."
Medtronic expects sales of only about $20 million in 2014.
Dr. John Jarcho, deputy editor of the New England Journal of
Medicine and assistant professor at Harvard Medical School, said
European counterparts need to take the failed trial into account. "I
don't think it can be business as usual," he said.
"If I were a patient, I would choose not to have the procedure."
European-based heart doctors who talked to Reuters at the meeting
were not ready to pull the plug.
"We don't need a moratorium because safety is not the issue," said
Dr. Steven Chamuleau of University Medical Center in Utrecht,
Netherlands.
Dr. Francois Schiele, chief cardiologist at University Hospital of
Besancon in France, said sales of the Medtronic product probably
should be suspended, but he was unsure about rival products.
"We have to continue with ongoing trials," said Schiele, a member
of the press committee of the European Society of Cardiology. "If
another trial is negative, then we'll probably have to question
whether we should stop."
Boston Scientific, in an emailed statement, said it believes that
its Vessix denervation system "is a highly differentiated technology
supported by compelling clinical evidence." It said it would work
with the scientific community to determine the next steps in its
clinical program.
St. Jude Medical said it would study the Symplicity data but still
believes in the technique and its product.
Several doctors questioned whether the Medtronic device actually
destroyed the nerve endings as intended. They suggested that some
kind of diagnostic test to confirm actual denervation may be needed
to advance the field.
"When the dust clears, there will be evidence denervation works, and
this will be one blip in the history of this technology," said Dr.
Robert Siegel, professor of medicine at Cedars-Sinai.
(Reporting by Bill Berkrot and Ransdell Pierson;
editing by Michele
Gershberg, Ken Wills and Douglas Royalty)
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