99812-114

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Background: Patients with ESFT resistant to second-line therapy, such as topotecan plus cyclophosphamide, have a dismal prognosis and few therapeutic options. Docetaxel (D), a microtubule inhibitor, demonstrated activity in patients with ESFT (Zwerdling T et al. Cancer 2006:106:1821-1828). Irinotecan (I), a toposiomerase I inhibitor, is being evaluated in clinical trials for ESFT. Despite the different mechanisms of action of D and I, and their activities as a single-agent against ESFT, DI combination has not been previously evaluated in ESFT. Thus, we prospectively performed a single-arm, phase II trial of DI in a single center in Korea. Methods: Patients <30 years with ESFT, who failed second-line therapy, were eligible for the study. D was administered IV over 60 minutes at a dose of 100 mg/m² on Day 1, and I at a dose of 80 mg/m² over 90 minutes on Days 1 and 8 of a 21-day cycle until disease progression. The primary end-point was objective response assessed by RECIST; the secondary end-point was safety. All toxicities were graded according to the National Cancer Institute’s Common Toxicity Criteria (version 4.0). Results: Of seven eligible patients (4 males; median age, 17 years (range 5-21)), 4 were recurrent/refractory cases, and 3 refractory cases. Median number of previous regimens was 6 (range 3-6). One CR, 1 PR, and 5 PD were obtained by DI combination (median number of cycles, 2 (range 1-15)), with objective response (CR+PR) rate of 2/7 (28.6%). One patient with PR achieved CR with subsequent surgery. CR of these two patients lasted 8.9 months and 10.6 months. Of all seven patients fully evaluable for toxicity, grade 4 neutropenia occurred in 7 (100%); grade 3 and 4 thrombocytopenia in 1 (14%) and 6 (86%), respectively; grade 3 pericardial effusion, paresthesia, motor weakness, oral mucositis, each in one (14%). Two patients required ≥1 dose delay; 2 required ≥1 dose reduction due to adverse events, but no one experienced treatment-related mortality. Conclusions: DI combination demonstrated activity in children and young adults with ESFT who were heavily pre-treated, and was feasible.