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Studies of a class
of rheumatoid arthritis drugs on the market revealed cases
of lymphoma, a blood cancer, in treated patients. Now, as
part of a safety review, the U.S. Food and Drug Administration
(FDA) wants an advisory panel’s advice on how to best
study the issue and express a warning on the drugs’ labels.
The drugs, which
are used to treat advanced cases of the disease, include Abbott
Laboratories’ Humira, Johnson & Johnson's Remicade
and Amgen’s Enbrel. The medicines are injected and bioengineered
to block a protein called tumor necrosis factor, or TNF, which
is linked to the inflammation that causes painful, inflamed
joints in people with rheumatoid arthritis.
However, although
the TNF molecule causes discomfort in people with rheumatoid
arthritis, it also helps fight infection and possibly cancer.
Along with lymphoma
risk, the medications have already been linked to other serious
side effects, such as higher risks of infection and tuberculosis.
According to the
panel, of 8,000 patients treated with the drugs, 24 developed
lymphoma as compared with none of the patients taking the
placebo.
However, previous
studies have also found an increased risk of lymphoma among
patients with rheumatoid arthritis, which makes it difficult
to determine whether the drugs or the disease are related
to the occurrences of lymphoma.
Humira's label
states that in clinical trials 10 lymphoma cases were observed.
It also says the role of this class of drugs in the development
of malignancies is unknown.
Remicade's label
also includes clinical trial data regarding malignancies and
says that the data is insufficient to determine whether the
drug plays a role.
Analysts expect
the FDA panel to recommend further studies and possibly enhance
safety precautions for this class of drugs. The FDA is not
required to accept the panel’s advice, though it typically
does. Analysts did not think the warnings would alter the
drugs’ combined 2003 sales, which they estimated would
reach over $3 billion.
Meanwhile, the
panel is also reassessing the safety of another rheumatoid
arthritis drug, Arava, because of increasing reports of liver
failure among treated patients.
Rheumatoid arthritis
affects mostly women, often starting between the ages of 25
and 50 years. The disease upsets the immune system, causing
it to attack the body’s cartilage and resulting in pain
and swelling and eventually destroying joints.
Seattle
Times March 5, 2003
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