[Clinical tolerability and pharmacokinetics of troxacitabine]

Objective: To investigate the safety and efficacy of troxatabine in advanced or relapsed malignant tumors resistant to standard therapy in China. Methods: This is a phase Ⅰ prospective study. During dose escalation, patients in Cancer Hospital, Chinese Academy of Medical Sciences received a single-dose intravenous infusion of troxacitabine. The planned dosing groups were 1.8, 3.6, 4.8, 6.4 and 8.0 mg/m(2) on days 1 and 8 every 3 weeks. The data of all patients were collected for safety analyses. Safety and tolerability were evaluated by monitoring adverse events. Results: Nineteen patients were enrolled from April 2018 to May 2019. The major adverse events were fatigue (89.5%, 17/19), leukopenia (84.2%, 16/19) and neutropenia (78.9%, 15/19). The dose limiting toxicity was neutropenia. The maximum tolerated dose was 6.4 mg/m(2). The best effect was stable disease (43.8%). The half-life of elimination phase from 15.91 hours to 76.63 hours in each dose group. Conclusions: The toxicity of troxacitabine is well tolerant. We recommend that the dose for Phase Ⅱ clinical trial should be 6.4 mg/m(2).