BackgroundFludarabine monophosphate and 2Chlorodeoxyadenosine are nucleoside analogues with activity against Waldenström macroglobulinemia. However, it is not clear whether prior exposure to one analogue precludes response to the other compound.Patients and methodsFourteen patients with Waldenström's macroglobulinemia and prior exposure to fludarabine were treated with two courses of 2chlorodeoxyadenosine.ResultsThree out of four patients that had previously responded to fludarabine and were relapsing from unmaintained remission, achieved a partial response with 2chlorodeoxyadenosine therapy. However, only one out of 10 patients with disease resistant to fludarabine responded to 2chlorodeoxyadenosine.Conclusions2chlorodeoxyadenosine may be effective in patients with Waldenström macroglobulinemia sensitive to fludarabine. However, this compound has limited activity for patients with disease resistant to fludarabine.