Treatment of relapsed or refractory acute leukemia in childhood with bisantrene combined with high dose aracytine

Remission re-induction chemotherapy with clofarabine, topotecan, thiotepa, and vinorelbine for patients with relapsed or refractory leukemia

BACKGROUND

We determined the maximum tolerated dose (MTD) of clofarabine when administered with topotecan, vinorelbine, thiotepa, and dexamethasone (TVTC) for children with relapsed or refractory acute leukemia, and observed the efficacy and toxicities of this therapy.

PROCEDURE

Twelve patients with acute lymphoblastic or myeloblastic leukemia were given a 14-day remission induction therapy. Clofarabine was administered at a dose of 30 or 40 mg/m(2)/day over 2 hr for five consecutive days in six patients each. Patients who achieved a remission proceeded to a stem cell transplant (HSCT). A second cycle could be administered prior to HSCT.

RESULTS

Of the six patients at the 30 mg/m(2) clofarabine dose, two achieved a complete response (CR) and one a PR and proceeded to BMT. Three patients had progressive disease. Five of the six patients at the 40 mg/m(2) achieved a CR. Four proceeded to HSCT, and one relapsed prior to HSCT. One patient died on day 45 with marrow hypoplasia without evidence of leukemia. Hematologic and infectious adverse events were universal. The one dose limiting non-infectious toxicity observed was prolonged marrow hypoplasia.

CONCLUSION

TVTC has significant anti-leukemic activity in both acute lymphoblastic and myeloblastic leukemia. The MTD of clofarabine is 40 mg/m(2)/day in this combination. This is the recommended dose for the phase II study in patients with refractory or relapsed leukemia, a population which has limited therapeutic options.

DNA topoisomerases as targets for anticancer drugs

DNA topoisomerases are essential enzymes that regulate the conformational changes in DNA topology by catalysing the concerted breakage and rejoining of DNA strands during normal cellular growth. Over the past few years there has been considerable pharmacological interest in these enzymes because inhibitors of DNA topoisomerases represent a major class of anticancer drugs. This review highlights topoisomerase-targeting drugs that have shown promising anticancer activities. The mechanisms by which those drugs interfere with the catalytic cycles of type I and type II DNA topoisomerases and the factors involved in the development of resistance to these drugs are discussed.