Cyclocytidine in the treatment of refractory acute childhood leukemia: a Southwest Oncology Group Phase I-II study.

Thirty-seven children and adolescents with acute leukemia in relapse were treated with cyclocytidine in a cooperative group setting. Only one of the 27 evaluable patients achieved complete remission. A significant decrease (greater than or equal to 20%) in circulating and/or bone marrow leukemia cells occurred in an additional five patients. Drug toxicity was evaluated in 35 patients and included ten cases of jaw pain, two cases of hypotension, one case of fever, and one case of severe vomiting.