High-dose cytosine arabinoside in multiple myeloma.

In 14 patients with advanced refractory multiple myeloma, the effect of high-dose cytosine arabinoside (ara-C) administration was evaluated. There was one partial remission among 13 evaluable patients who received 2 g/m2 intravenously over 2 hr every 12 hr, for a total of 2-8 g/m2 per course, repeated every 3-4 weeks. Myelosuppression constituted the dose-limiting toxicity, causing two treatment-related deaths from infection and bleeding. Prior extensive therapy, a low percentage of cells in S phase and low levels of intracellular ara-CTP accumulation in the bone marrow could explain the resistance of myeloma to this treatment.