Phase II study of troxacitabine, a novel dioxolane nucleoside analog, in patients with refractory leukemia

Purpose: To investigate the activity of a novel dioxolane L-nucleoside analog, troxacitabine (L-(-)-OddC, BCH-4556), in patients with refractory leukemia. Patients and Methods: Study participants were patients with refractory or relapsed acute myeloid (AML) or lymphocytic (ALL) leukemia, myelodysplastic syndromes (MDS), or chronic myelogenous leukemia in blastic phase (CML-BP). Troxacitabine was provided as an intravenous infusion for more than 30 minutes daily for 5 days at a dose of 8.0 mg/m²/d (40 mg/m² per course). Courses were given every 3 to 4 weeks according to antileukemic efficacy. Results: Forty-two patients (AML, 18 patients; MDS, one patient; ALL, six patients; CML-BP, 17 patients) were treated. Median age was 51 years (range, 23 to 80 years); 22 patients were male. Stomatitis was the most significant adverse event, with three patients (7%) and two patients (5%), respectively, experiencing grade 3 or 4 toxicity. Ten patients (24%) had grade 3 hand-foot syndrome, and two patients (5%) had grade 3 skin rash. One patient (2%) had grade 3 fatigue and anorexia. Marrow hypoplasia occurred between days 14 and 28 in 12 (75%) of 16 assessable patients with AML. Two complete remissions and one partial remission (18%) were observed in 16 assessable patients with AML. None of six patients with ALL responded. Six (37%) of 16 assessable patients with CML-BP experienced a return to chronic-phase disease. Conclusion: Troxacitabine has significant antileukemic activity in patients with AML and CML-BP.