Heart Risk Seen in Drug For Anemia
- From: J <nexsw@nvalid,anon>
- Date: Tue, 27 Feb 2007 18:58:37 -0500
http://query.nytimes.com/gst/fullpage.html?res=9C04E3DF143EF935A25752C1A9609C8B63&sec=health&pagewanted=print
November 16, 2006
Heart Risk Seen in Drug For Anemia
By ALEX BERENSON
A medical study to be released today suggests that high doses of a
best-selling drug used to treat anemia in dialysis and cancer patients may
increase the risk of heart problems and deaths.
Almost a million Americans a year receive prescriptions for the drug,
known as epoetin, or darbepoetin, a closely related drug also used in
anemia treatment. Worldwide, sales of the two drugs -- sold under the
brand names Epogen, Procrit and Aranesp -- topped $9 billion last year for
Amgen and Johnson & Johnson, their makers.
Researchers for the study, to be published in The New England Journal of
Medicine, divided anemic patients with kidney disease into two groups. One
group received epoetin with a goal of almost fully correcting their
anemia, a lack of red blood cells associated with fatigue and shortness of
breath.
The others were allowed to remain more anemic and generally received less
epoetin. Patients in the first group were 34 percent more likely to die or
suffer heart problems than those in the second.
Dr. Ajay Singh, an associate professor at Harvard Medical School and the
study's lead author, said the results were surprising and should encourage
doctors to treat anemia less aggressively.
The study tested anemia in kidney patients who did not yet need dialysis,
a mechanical blood-filtering technique used to keep alive patients whose
kidneys have almost entirely failed. But its findings should apply to
patients on dialysis as well, Dr. Singh said.
The findings reinforce mounting concerns that kidney patients may be
receiving too much epoetin, in part because dialysis clinics make bigger
profits for providing larger doses. Studies show that the clinics make
little, if any, profit on the actual dialysis services they provide for
Medicare patients, who are the vast majority of patients.
The amount of epoetin received by the typical American dialysis patient
has nearly tripled since the early 1990s. The average patient now gets
epoetin doses similar to those given to the first group in Dr. Singh's
study. Death rates for dialysis patients are higher in the United States
than in Europe, where doses are comparable to the second group's, although
doctors say other factors may also explain the difference. About 22
percent of American patients die every year, compared with about 15
percent in Europe.
Dr. Singh said his study, with a second trial with similar results also to
be published today in The New England Journal, did not necessarily prove
that epoetin use was harmful.
But the studies show that the anemia of many patients is being
overcorrected and that doctors should aim for lower levels of red blood
cells in their patients, he said. The simplest way to do that would be to
give patients less epoetin.
Susan Cruzan, a spokeswoman for the Food and Drug Administration, said the
agency was aware of the study results and would evaluate the data. She
noted that Epogen's label already offered advice for doctors. The F.D.A.,
she said, will release a more complete advisory today.
Amgen, which sells epoetin under the brand name Epogen and darbepoetin
under the name Aranesp, said its drugs had been a boon for people with
anemia and are properly used in the vast majority of patients. In fact,
anemia may be undertreated in cancer and kidney patients, scientists at
Amgen argue.
Amgen said it was committed to the safety of its drugs and was conducting
a clinical trial to study Aranesp in 4,000 kidney patients. But some
scientists say that trial will not settle the most crucial issue about
epoetin and darbepoetin: whether the drugs are routinely overused.
In the first nine months of 2006, Amgen sold $4.9 billion of Aranesp and
Epogen, accounting for almost half its revenue. Sales of the two drugs
rose almost 15 percent compared with the period in 2005.
Johnson & Johnson, which sells epoetin under the brand names Procrit in
the United States and Eprex everywhere else, reported sales of $2.4
billion in the first nine months of 2006, down slightly from 2005.
Epoetin, a naturally occurring protein produced mainly in the kidneys,
stimulates bone marrow cells to produce hemoglobin, the main component of
red blood cells. Darbepoetin, which was introduced in 2001, is a version
of epoetin that has been slightly modified so that it does not need to be
given as frequently. Both drugs are given via injection.
Since epoetin was approved in 1989, it has become a standard treatment for
more than 90 percent of dialysis patients in the United States, and it is
increasingly used for patients with earlier-stage kidney disease. The drug
is also widely used for cancer patients, who often suffer from anemia as a
side effect of chemotherapy. Some cancers can also cause anemia on their
own.
Many kidney and cancer doctors and patients say epoetin has greatly
improved the lives of people receiving dialysis or chemotherapy. Severe
anemia can be debilitating, leaving patients unable to work, walk for over
a few minutes or even think clearly, as well as increasing their risk of
infection and heart disease.
Before epoetin, blood transfusions were the only effective treatment for
anemia. But transfusions carry a risk of infection and can eventually
prevent patients from receiving transplants. For most patients, epoetin
appeared a safe alternative.
''The drug in and of itself has really advanced care for patients, so that
they're able to go back to do the things that they previously couldn't,''
said Kris Robinson, the executive director of the American Association of
Kidney Patients and a kidney transplant recipient. ''It makes a huge
difference.''
There are no set doses of epoetin. Instead, it is given with the goal of
raising hemoglobin levels to a specific target level. Aiming for a higher
average hemoglobin target effectively raises the amount of epoetin that
patients receive.
The prescribing label for Epogen, which is approved by the F.D.A., says
dialysis patients should have a target hemoglobin level of 10-12 grams per
deciliter of blood. In general, healthy adult men have hemoglobin levels
of 14 grams or more per deciliter and patients are considered to need
treatment if their levels are below 10 grams.
But guidelines devised by the National Kidney Foundation say a target of
11 to 13 grams is appropriate. Amgen sponsored the development of those
guidelines, though the National Kidney Foundation said the company had not
influenced them.
The difference between the F.D.A. and Kidney Foundation guidelines may
seem small. But Dr. Singh's study compared patients with an average
hemoglobin of 12.6 grams with those who had an average of 11.3 grams, and
found a 34 percent greater incidence of deaths and heart attacks in those
with the higher levels.
In the United States, the average dialysis patient has a hemoglobin level
just under 12 grams , according to data from the United States Renal Data
System, which monitors kidney patient care. Almost 20 percent of patients
have levels above 13 grams.
Davita, the second-largest dialysis provider, is especially aggressive
about increasing hemoglobin levels, according to the data system. A paper
that will be presented Saturday at the American Society of Nephrology's
annual conference in San Diego found that 37 percent of Davita patients
reported hemoglobin levels greater than 14 grams at least once in a
nine-month period, an abstract of the paper posted online said.
The paper's authors did not return calls for comment on it.
Dr. Charles McAllister, Davita's chief medical officer, said the company
did not aim for hemoglobin targets higher than 13 grams per deciliter. But
some patients go over that benchmark because hemoglobin levels naturally
vary over time, he said.
Despite Dr. Singh's study and the F.D.A. label on Epogen, Dr.McAllister
said he thought patients would benefit from hemoglobin as high as 13 grams
per deciliter.
But Daniel Coyne, a kidney doctor and professor of medicine at Washington
University in St. Louis, said Dr. Singh's study adds to a growing body of
evidence that American patients receive too much epoetin and that
hemoglobin targets are too high.
''There's enough study evidence to say that a higher hemoglobin carries an
increased risk of harm,'' Dr. Coyne said. ''Above 12 carries increasing
risk that is unacceptable given the occasional improvements of quality of
life.''
.
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