Phase II window of idarubicin in children with extraocular retinoblastoma

The aim of this study was to evaluate in an upfront phase II study the response to idarubicin in children with extraocular retinoblastoma.

The starting dose of idarubicin was 15 mg/m(2)/d (days 1 and 2) weeks 0 and 3. After an interim evaluation, the dose was reduced to 10 mg/m(2)/d (days 1 and 2) weeks 0 and 3 because of hematopoietic toxicity. Response was evaluated at week 6.

At the Hospital JP Garrahan (Buenos Aires, Argentina), 10 patients (five bilateral) were entered onto the study from 1995 to 1998. A total of 19 cycles were administered. Extraocular sites included orbit (n = 10), bone marrow (n = 3), bone (n = 1), lymph node (n = 1), and CNS (n = 1). The response rate was 60% (95% confidence interval, 30% to 90%). One complete response was achieved, in addition to five partial responses, two cases of stable disease, and two cases of progressive disease. All patients with bone marrow involvement achieved complete clearance of tumor cells. The patient with CNS disease had progressive disease. All patients had severe hematopoietic toxicity (grade 4 neutropenia and grade 3/4 thrombocytopenia after most cycles). Other toxicities included grade 2 diarrhea in 30%. No echocardiographic changes were detected.

Idarubicin is active in extraocular retinoblastoma. The activity of this drug should be explored in future phase III studies.