Treatment of adult acute leukemia with arabinosylcytosine and thioguanine

Forty unselected adults with acute leukemia were treated with CA (2–3 mg/kg) by daily rapid intravenous injection and TG (2.5 mg/kg) orally. Two patients were judged to have had an inadequate trial, having died after 3 and 4 days. Of 38 adequately treated patients, 2 had acute lymphoblastic and 36 acute myeloblastic, monoblastic, or myelomonoblastic leukemia. Twenty‐eight patients had had previous chemotherapy (19 with either CA or 6‐MP alone) but had failed to respond or had relapsed and were refractory. The 38 adequately treated patients had 1 or more courses of CA and TG of 8–32 days each as limited by individual tolerance. The drugs caused moderate or severe pancytopenia and marrow hypoplasia in all but 3 patients treated. Twenty‐one of 38 patients had remission with M‐1 marrows lasting an average 6 (1.5–13) months with 6 patients still in remission. Seventeen of 21 patients had H‐1 peripheral blood ratings (normal platelet, leukocyte and hemoglobin values) and 4 had H‐2 ratings, all because of low hemoglobin. Twenty patients in remission were given maintenance therapy; the dosage varied but is currently TG 2.5 mg/kg 4–5x/wk + CA 2–3 mg/kg 1‐2x/wk.