Response to 2-chlorodeoxyadenosine in patients with B-cell chronic lymphocytic leukemia resistant to fludarabine.
BACKGROUND
Patients with untreated B-cell chronic lymphocytic leukemia have a high rate of complete remission when given the halogenated nucleoside analogue fludarabine. However, patients in whom the disease has proved refractory to primary treatment have a reduced life expectancy and a dismal outcome.


METHODS
We treated four consecutive patients who had unsatisfactory responses to second-line or subsequent treatment with fludarabine with another halogenated nucleoside analogue, 2-chlorodeoxyadenosine.


RESULTS
One patient with progressing lymphocytosis, anemia, and thrombocytopenia despite 10 courses of fludarabine entered a complete remission when treated with 2-chlorodeoxyadenosine. Two patients who had less-than-partial remissions after six courses of fludarabine had good partial remissions when treated with 2-chlorodeoxyadenosine. One patient with Coombs-positive hemolytic anemia who had no response to three courses of fludarabine had a partial remission, with resolution of hypogammaglobulinemia, when treated with 2-chlorodeoxyadenosine.


CONCLUSIONS
There was no evidence of cross-resistance between fludarabine and 2-chlorodeoxyadenosine despite their similar structures. 2-Chlorodeoxyadenosine may induce a complete remission in chronic lymphocytic leukemia that is highly resistant to chemotherapy, and it deserves wider clinical evaluation in patients with this condition.
Juliusson
G
G
Department of Medicine, Huddinge Hospital, Sweden.
Elmhorn-Rosenborg
A
A
Liliemark
J
J
D015762:2-Chloroadenosine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000328:Adult; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D017338:Cladribine; D003839:Deoxyadenosines / Q000627:therapeutic use*; D004351:Drug Resistance; D005260:Female; D006242:Haptoglobins / Q000032:analysis; D006801:Humans; D007136:Immunoglobulins / Q000032:analysis; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000188:drug therapy*; D007958:Leukocyte Count; D008214:Lymphocytes; D008297:Male; D008875:Middle Aged; D012074:Remission Induction; D014740:Vidarabine / Q000031:analogs & derivatives / Q000627:therapeutic use
D000970:Antineoplastic Agents; D003839:Deoxyadenosines; D006242:Haptoglobins; D007136:Immunoglobulins; D015762:2-Chloroadenosine; D017338:Cladribine; D014740:Vidarabine; C024352:fludarabine