Treatment of leukemia with low dose Ara-C: a study of 159 cases.

The management of acute leukemia has been transformed by the advent of major antimitotic agents. Intensive combination drug therapy has given excellent results for many patients, but in certain cases it remains dangerous (acute leukemia in elderly patients) or ineffective (refractory anemia with excess blasts (RAEB), secondary leukemia, leukemic relapse). Allogeneic bone marrow grafts are also limited by the particular conditions required (compatibility of MHC, age). In vitro studies by Lotem and Sachs [1] demonstrated the differentiation of leukemic cells from normal cells, raising new hopes of therapeutic possibilities. In recognition of this, clinical trials with low dose cytosine arabinoside (LD Ara-C) were undertaken. Success was obtained for one case of RAEB and two cases of acute nonlymphoblastic leukemia (ANLL) unresponsive to combination chemotherapy [2]. The first substantial series (23 patients) showed that it was possible to obtain complete remission in all categories ofleukemia [3]. Several clinical trials with LD Ara-C have recently been reported, but the small number of patients in each series (less than 20) and the contradictory results render a conclusive judgement impossible. Thus, a number of questions have yet to be answered. What is the efficacy of LD Ara-C