Idarubicin and standard-dose cytosine arabinoside in adults with recurrent and refractory acute lymphocytic leukemia

BACKGROUND. Drug resistance and early disease recurrence were major contributing factors in the limited survival of patients with acute lymphocytic leukemia (ALL). New chemotherapeutic agents and drug combinations were employed in refractory patients to overcome drug resistance. METHODS. The current study evaluated the efficacy of a regimen comprising intravenous bolus injections of idarubicin, 12 mg/m² daily × 3, and a continuous 7-day infusion of cytosine arabinoside (ara-C), 100 mg/m2 daily, in adults with refractory or recurrent ALL. Twenty patients aged 14-75 years were treated. RESULTS. Six patients (30%) achieved complete remission (CR), 5 (25%) had a partial response (PR), and 9 (45%) did not respond. Recovery of blood counts occurred at a median of 20 days. One patient who achieved CR and one who achieved PR survived 1.5 and 2 years, respectively, after receiving this treatment. The median response and overall survival periods were 2.75 and 6.3 months, respectively. There was no relation between remission duration and previous chemotherapy. Neither leukocyte count at study entry nor patient karyorype was associated with attainment of CR. All patients experienced profound myelosuppression. Gastrointestinal toxicity was mild to moderate, with the exception of one case of World Health Organization Grade 3 mucositis. CONCLUSIONS. The regimen of idarubicin and ara-C achieved a 55% overall response rate in patients with recurrent or refractory ALL. This response rate compared favorably with other regimens and was achieved with acceptable toxicity. Response duration was disappointing, however.