Activity of indicine N-oxide in refractory acute leukemia.

Indicine N-oxide, the first pyrrolizidine alkaloid N-oxide to be studied in the treatment of cancer in humans, was administered to ten patients: four children and two adolescents with refractory acute lymphocytic leukemia and four adults with refractory acute nonlymphocytic leukemia (three acute myelocytic, one myelomonocytic). Two patients, a 4-year-old boy with acute lymphocytic leukemia and a 22-year-old man with acute myelocytic leukemia, achieved complete remission lasting 3 and 5+ months, respectively. Another 15-year-old male with acute lymphocytic leukemia had a partial remission for four months. Toxicities included bone marrow suppression, mild anorexia and nausea, and transient elevation of liver enzymes. Jaundice and liver failure, presumably induced by drug, occurred in two patients.