Phase I evaluation of beta-2'-deoxythioguanosine in pediatric patients with leukemia.

Thirty-one pediatric patients with acute leukemia who had relapsed on either 6-mercaptopurine or 6-thioguanine were treated with beta-2'-deoxythioguanosine, which was administered as an iv infusion every 12 hours for three or six doses every 2 weeks. Severe nausea and vomiting and urate nephropathy were the dose-limiting toxic effects. Therapeutic responses occurred in four of 24 children with acute lymphocytic leukemia and in two of seven with acute nonlymphoblastic leukemia.