Phase I and Pharmacokinetic Studies of Erlotinib Administered Concurrently with Radiotherapy for Children, Adolescents,and Young Adults with High-Grade Glioma

ALBERTO BRONISCER,; SUZANNE J. BAKER; CLINTON F STEWART; THOMAS E.MERCHANT; FRED H. LANINGHAM; PAULA SCHAIQUEVICH; MEHMET KOCAK; E. BRANNONMORRIS; RAELENE ENDERSBY; DAVID W. ELLISON,; AMAR GAJJAR

CLINICAL CANCER RESEARCH

AMER ASSOC CANCER RESEARCH

Año: 2009 vol. 15 p. 701 - 707

1078-0432

Purpose: To estimate the maximum-tolerated dose (MTD) of erlotinib administered during andafter radiotherapy, and to describe the pharmacokinetics of erlotinib and itsmetaboliteOSI-420 in patients between 3 and 25 years with newly diagnosed high-grade glioma who did not requireenzyme-inducing anticonvulsants. Experimental Design: Five dosage levels (70, 90, 120, 160, and 200 mg/m2per day) were planned in this phase I study. Dose-limiting toxicities (DLT) were evaluated during first 8 weeks of therapy. Local radiotherapy (dose between 54and 59.4Gy) and erlotinib started preferentially on the same day. Erlotinib was administered once daily for a maximum of 3 years. Pharmacokinetic studies were obtained after first dose and on day 8 of therapy. Mutational analysis of EGFR kinase domain, PIK3CA,and PTEN was done in tumor tissue.Results: Median age at diagnosis of 23 patients was 10.7 years (range, 3.7-22.5 years). MTDof erlotinib was 120 mg/m2 per day. Skin rash and diarrhea were generally well controlled withsupportive care. Dose-limiting toxicities were diarrhea (n = 1), increase in serum lipase (n =1),and rash with pruritus (n = 1). The pharmacokinetic variables of erlotinib and OSI-420 in children were similar to those described in adults. However, there was no relationship between erlotinib dosage and drug exposure. No EGFR kinase domainmutationswere observed.Two patientswith glioblastoma harbored mutations in PIK3CA (n =1)or PTEN (n =1).Conclusions: Although the MTD of erlotinib in children with newly diagnosed high-gradeglioma was 120 mg/m2 per day, pharmacokinetic studies showed wide interpatient variability drug exposure.