9553 Background: High-grade gliomas are uncommon neoplasms in childhood that portend a poor prognosis. Because of the promising activity of erlotinib in adults with high-grade glioma, we conducted this Phase I study to determine the maximum tolerated dose and dose limiting toxicity (DLT) of erlotinib administered concurrently with and after RT. Methods: Patients between 3 and 25 years of age with newly diagnosed high-grade glioma received erlotinib continuously once daily during and after RT for a maximum of 52 weeks. Pharmacokinetic studies of erlotinib and its metabolite OSI-420, and genotyping were performed during course 1 in consenting patients. Use of enzyme-inducing anticonvulsants was an exclusion criterion. Dose escalation followed a typical Phase I design (dosage levels of 70, 90, and 120 mg/m2 per day). The DLT-evaluation period comprised the first 8 weeks of erlotinib. Results: Seventeen patients (median age 10.4 yrs; 10 males) were enrolled. Diagnoses consisted of glioblastoma (n=9), anaplastic astrocytoma (n=4), and other high-grade gliomas (n=4). Two of seven patients experienced reversible grade 3 hypokalemia / hypophosphatemia at the 70 mg/m2 level. Once electrolyte abnormalities were excluded as DLT, only one of seven patients at the 120 mg/m2 level has experienced grade 3 diarrhea so far. Pharmacokinetic studies were obtained in 14/17 patients. At the 70 mg/m2 dosage level, the median (range) erlotinib and OSI-420 Cmax and Tmax were 1,405 ng/ml (937–2,180) and 4.1 hr (2.2–8.2) and 158.5 ng/ml (45–203) and 4.1 hr (2.2–7.9), respectively. Three patients have received erlotinib for more than 1 year with disease stabilization. Six patients have already experienced disease progression. Conclusions: Erlotinib administered concurrently with RT on this schedule has been well tolerated. Preliminary pharmacokinetic results are comparable to those observed in adults. Rather than continue to escalate erlotinib dosages, we plan to complete this study and open a phase II study of erlotinib and RT for this same patient population. No significant financial relationships to disclose.
P09.50 Phase I trial of temozolomide plus bevacizumab for newly diagnosed high-grade gliomas in the elderly: Interim report
