Data presented at the Joint International Congress on
Acute Promyelocytic Leukemia and Differentiation Therapy demonstrated that
patients with acute promyelocytic leukemia (APL) treated with arsenic trioxide
achieved an overall survival at 24 months of 63%.
"Trisenox is a major medical breakthrough for the thousands of relapsed
APL patients whose previous treatments were unsuccessful," said Steven L.
Soignet, MD, principal investigator of the arsenic trioxide pilot and pivotal
clinical trials. "The high rate of complete remission and relapse-free
survival associated with the use of this drug is very encouraging news for this
patient population, which traditionally has had a very poor prognosis."
The data on arsenic trioxide presented at this meeting combines the results
of two clinical studies that enrolled 52 patients with a median age of 39 years.
One study was a pilot study in 12 patients with relapsed APL conducted at
Memorial Sloan-Kettering Cancer Center, and the other, a 40-patient pivotal
trial conducted at nine medical centers across the United States. The results of
the larger trial were published in a recent issue of the Journal of Clinical
Oncology (9:3852-3860, 2001).
Patients were treated with 1- to 2-hour infusions of arsenic trioxide daily
until the time of bone marrow complete remission. Those who experienced a
complete response were offered one consolidation course of arsenic trioxide that
began 3 to 4 weeks later. Patients who maintained a complete response were
eligible to receive additional cycles of arsenic trioxide in a maintenance
study, and some patients underwent transplants.
A total of 45 patients achieved a complete remission, for an overall response
rate of 87%, with a 2-year relapse-free survival rate of 49%. Toxicities were
manageable, and there were no treatment-related deaths during the study.
"These results confirm Trisenox as a highly effective therapy for
patients with APL in whom standard treatments have failed," said Martin S.
Tallman, MD, associate professor of Medicine at Northwestern University Medical
School. "They are particularly important because few treatment options have
been available for patients with relapsed disease."