B. Filleul et al., A SINGLE COURSE OF 2-CHLORO-DEOXYADENOSINE DOES NOT ERADICATE LEUKEMIC-CELLS IN HAIRY-CELL LEUKEMIA PATIENTS IN COMPLETE REMISSION, Leukemia, 8(7), 1994, pp. 1153-1156
The nucleoside analog 2-chlorodeoxyadenosine (2-CdA) has recently emer
ged as a most promising treatment for hair-cell leukemia (HCL). The re
sponse rates are high regardless of prior therapy, and the duration of
complete responses (CR) after a single course of treatment is longer
than with any other therapeutic agent. We investigated the presence of
minimal residual disease (MRD) in ten HCL patients treated in our ins
titution with 2-CdA. The presence of residual leukemic cells was inves
tigated in patients in CR following one course of treatment, using the
polymerase chain reaction (PCR) and heavy-chain immunoglobulin genes
(IgH), or TCR delta derived clonospecific probes. Eight patients achie
ved a comlete remission after a single course of treatment, as evaluat
ed at 6 months. Among these patients, seven are still in CR with a med
ian follow-up of 12 months (range, 6-20 months) and one has relapsed a
fter 15 months. Using PCR, all the evaluable patients remaining in CR
showed persistent evidence of detectable MRD with no sign of decrease
over the observation period. From this small series, we conclude that
a single course of 2-CdA does not eradicate HCL and that persistence o
f residual leukemic cells appears to be common in patients in complete
morphologic remission. Whether persistence of MRD will have an impact
on long-term outcome, or whether HCL patients in morphologic CR with
persistent MRD will remain so, is a matter of longer follow-up.