Melphalan was injected 275 times, in doses ranging from 2 to 7.5 mg (mean and mode, 4 mg). For melphalan, the dose was increased from 3.0 to 7.5 mg; at the latter dose, local toxicity was observed. We currently consider the standard dose of melphalan to be 5.0 mg for a 3-year-old child. Topotecan was used 97 times, always in association with melphalan or carboplatin, and the dose ranged from 0.15 to 1.5 mg (mean, 0.5 mg; mode, 0.3 mg). We started with a dose of 1.5 mg, but we noted significant decreases in the amplitudes of the ERGs at 4 weeks in the first set of patients. Therefore, we decreased the dose, and we currently use a standard dose of 0.4 mg for a 3-year-old child. Carboplatin was used 18 times, alone or in association with melphalan or topotecan, in doses ranging from 15 to 50 mg (mode, 30 mg). The dose was increased from 15 mg (minimally effective) to 50 mg (resulting in inflammatory reaction), and we currently use a standard dose of 30 mg for a 3-year-old child. Methotrexate was used twice (at 6 and 12 mg) but was found to be ineffective at these doses. Table 3 reports the dosages that we used after the initial dose-finding phase.