NEW YORK, Nov 17 (Reuters Health) -- The drug thalidomide, once banned in
most countries, holds promise as a therapy for a type of bone marrow cancer, US
researchers report.
Known as multiple myeloma, the cancer is relatively uncommon. Treatment
that includes high doses of chemotherapy helps diminish tumors in some people,
but it is not effective for everyone with the disease.
Since thalidomide helps to suppress the production of new blood vessels,
which are necessary for tumors to grow, Dr. Bart Barlogie, of the University of
Arkansas for the Medical Sciences in Little Rock, and colleagues suspected that
the drug might be helpful for people with bone marrow cancer.
In the 1960s, thalidomide was found to cause severe birth defects in
children of mothers who took it for morning sickness. The drug had not been
approved for sale in the US at that time, and it was subsequently banned in most
countries.
In recent years, studies have suggested that the drug may be a treatment
for a variety of medical conditions, including some types of cancer. In 1998,
the US Food and Drug Administration approved thalidomide for the treatment of
leprosy. That opened the door for "off-label use," in which a drug approved to
treat one disorder is also prescribed for other ailments.
Barlogie and his colleagues gave thalidomide to several patients with
multiple myeloma who had not benefited from other treatments. The results were
"dramatic," Barlogie told Reuters Health. In fact, in one patient, thalidomide
almost completely eliminated the cancer within 3 months.
To test the effect of the drug in a larger group of people, Barlogie's
team studied 84 patients with multiple myeloma who had not responded to previous
treatment. During the study, the researchers measured blood and urine levels of
a substance called paraprotein, which is produced by a tumor. A drop in these
levels may signal that the cancer is beginning to weaken, Barlogie said in the
interview with Reuters Health.
Levels of this tumor marker declined by at least 25% in nearly one third
of the patients, Barlogie and his colleagues report in the November 18th issue
of The New England Journal of Medicine. Seven patients experienced a decrease of
at least 50%, six had a decrease of at least 75%, and eight had a decrease of at
least 90%.
Moreover, in two patients the cancer was eliminated completely. In the
interview with Reuters Health, Barlogie warned that a drop in paraprotein levels
is not a guarantee that a tumor is decreasing in size. Thalidomide might simply
have been blocking the production of the paraprotein, not actually fighting the
tumor itself, he added.
In most of the patients, however, the investigators detected additional
signs that the cancer was weakening. Based on the findings, Barlogie said, "This
drug has a major role to play in the treatment of myeloma." He and his
colleagues are currently testing the effects of thalidomide in combination with
chemotherapy.
