(Corrects name of drug maker in sixth paragraph to Cephalon
By Julie Steenhuysen
CHICAGO, June 2 Arsenic, the poison of choice
for many a murder mystery, can significantly extend survival in
patients with a rare form of leukemia, U.S. researchers said on
"It's a much smaller dose than you would use to poison
people," added Dr. Bayard Powell of Wake Forest University
Baptist Medical Center.
Adding arsenic to standard treatment can extend patients'
lives and prevent relapse, Powell said. And the effect is so
impressive that patients may some day be able to skip
chemotherapy -- but that will take more testing.
"This study has redefined the standard of care," said
Powell, who presented results from the large, three-year study
at a meeting of the American Society of Clinical Oncology in
"The people who took arsenic lived longer," Dr. Nancy
Davidson, president-elect of the American Society of Clinical
Oncology, told Reuters.
The drug, arsenic trioxide, which is made by Pennsylvania
based Cephalon Inc. CEPH.O and sold under the brand Trisenox,
is approved for people with acute promyelocytic leukemia, or
APL, whose disease has returned.
Standard treatment for APL -- a form of acute myeloid
leukemia that strikes 1,500 people a year in the United States
-- involves chemotherapy and a form of vitamin A called
all-trans retinoic acid, which helps 70 to 80 percent of
patients gain long-term remission.
About 25 percent of these patients, however, relapse and no
longer respond to treatment. These patients often get arsenic
But in a study sponsored by The National Cancer Institute
Powell and colleagues paired arsenic with standard treatment in
newly diagnosed patients.
They found that 81 of 261 patients in the arsenic group
were free of disease after three years, compared with 66 of 257
patients in the group who got the standard regimen alone.
"Among those who actually got arsenic, only five patients,
or 2 percent, relapsed," Powell said. "This is very
Powell thinks the drug will be used as a first treatment
right after chemotherapy.
"The next question is how far do we move it forward?" he
He said future studies will test whether patients can skip
chemotherapy and just take arsenic.
Dr. Mitchell Smith, director of the lymphoma service at Fox
Chase Cancer Center in Philadelphia, said the therapy's effect
is compelling but he is not yet ready to rule out chemotherapy,
at least not without more study.
While most chemo treatments are toxic and work by killing
cells, arsenic trioxide zeros in on disease-causing cells.
"It seems to kill preferentially," Smith said.
Arsenic has been used as a traditional therapy in China for
more than 2,000 years, but its use in the United States is
still rather novel.
"Patients look up and pay attention when you mention you
are going to treat them with arsenic," Powell said.