PARIS, France--Cyclophosphamide with total body irradiation (TBI)
provides better survival rates than cyclophosphamide plus busulfan
when used as a pre-autologous bone marrow transplant (ABMT) conditioning
regimen in patients with advanced acute myeloid leukemia (AML),
a University of Minnesota study has found.
The Minnesota study included 75 patients, 35 of whom were participants
in a randomized trial comparing the two conditioning regimens.
Autologous marrow was purged with 4-hydroperoxycyclo-phosphamide
For patients beyond first remission, cyclophosphamide (Cytoxan,
Neosar), 120 mg/kg, plus 1,320 cGy TBI given in eight fractions
over 4 days, was associated with a 2-year disease-free survival
rate of 38%, compared with 7% for a regimen of cyclophosphamide,
200 mg/kg, plus busulfan (Myleran), 16 mg/kg.
"There was a clear advantage of cyclophosphamide/TBI over
busulfan/cyclophosphamide," Kathryn E. Dusenbery, MD, said
at the American Radium Society meeting. Among patients in first
remission, however, the survival differences did not reach statistical
Dr. Dusenbery pointed out that there were no differences between
the two regimens in the time required for the absolute neutrophil
count to reach 500, or in the duration of hospital stay. Likewise,
she observed, the incidence of acute toxicity, including interstitial
pneumonitis and hemorrhagic cystitis, was similar in both study
In contrast, veno-occlusive disease developed in seven patients
conditioned with busulfan/cyclophosphamide, but in none of those
who received chemotherapy plus TBI.
"In the future, our preferred regimen will be cyclophosphamide
and TBI," Dr. Dusenbery said. "It is unlikely that we
will be able to escalate the TBI doses too much beyond the 1,320
cGy we use now," she added.