Forty-five patients with untreated, de novo acute myeloid leukemia (AM
L) were treated with high-dose cytosine arabinoside (Ara-C) plus mitox
antrone or daunorubicin. Forty-two patients entered complete remission
with recovery of normal blood counts. Seven of these patients were ex
cluded from further analysis (two, early consolidation chemotherapy; f
our, early relapse; one, hypersplenism). Of the remaining 35 patients,
20 (57%) developed thrombocytopenia and anemia (with or without neutr
openia) a median of 3 weeks after entering complete remission. Post-re
mission cytopenias were more common in patients receiving mitoxantrone
(81%) compared to those receiving daunorubicin (37%; p < 0.003). The
cytopenias lasted a median of 54 days. Four of five patients in whom t
he cytopenias did not recover received mitoxantrone. Leukemia relapse
or myelodysplasia did not explain these cytopenias. Post-remission cyt
openias resulted in a greater than 90-day delay or prevention of plann
ed autologous bone marrow transplantation in 13 of 17 otherwise eligib
le patients. We conclude that post-remission cytopenias are common fol
lowing blood count recovery in AML patients entering complete remissio
n with high-dose Ara-C and mitoxantrone or daunorubicin. Postremission
cytopenias do not necessarily imply leukemia relapse.