The promising results obtained with Fludara I.V. (fludarabine phosphate) treatment in the common indolent B-cell neoplasms have led to their further evaluation in other unusual B-cell malignancies, in Hodgkin's disease, and in T-cell diseases. A significant response rate has been found among patients with macroglobulinemic lymphoma, those with prolymphocytic leukemia or prolymphocytoid variant of chronic lymphocytic leukemia, and those with mycosis fungoides. The limited therapeutic data in hairy-cell leukemia and in Hodgkin's disease are also interesting.