Search

The treatment of children with malignant glioma remains challenging. The aim of this multicenter phase I study is to establish the recommended dose (RD) of the combination therapy with temozolomide (TMZ) and oral etoposide (VP-16) in children with relapsed or refractory malignant glioma and brainstem glioma at diagnosis. A phase I trial was conducted to establish the maximum tolerated dose (MTD) of TMZ and oral VP-16. This orally administered combination was investigated by a classical 3 + 3 design. Cohorts of patients were enrolled at 4 different levels: (1) TMZ 120 mg/m on days 1-5 and VP-16 50 mg/m on days 1-8; (2) TMZ 150 mg/m on days 1-5 and VP-16 50 mg/m on days 1-8; (3) TMZ 150 mg/m on days 1-5 and VP-16 50 mg/m on days 1-10; (4) TMZ 150 mg/m on days 1-5 and VP-16 50 mg/m on days 1-12. Therapy was administered in 28-day courses. A total of 118 courses were administered to 18 patients with a median age of 11.2 years. At dose level 1, none displayed toxicity. Of the 6 patients at dose level 2, 1 patient had dose limiting toxicity (DLT). None of the 3 patients at dose level 3 had DLT. At dose level 4, grade III/IV thrombocytopenia and neutropenia were observed in 2 out of the 6 patients enrolled. Therefore, the MTD was established at dose level 3. The RD for phase II trial in children with malignant glial is TMZ 150 mg/m for 5 days and VP-16 50 mg/m for 10 days every 28 days. [ABSTRACT FROM AUTHOR]

Temozolomide (TMZ) is an oral alkylating agent with proven antitumoral activity in preclinical and clinical studies in adults with high-grade glioma (HGG). However, only limited efficacy has been reported in children with HGG using the 5-day schedule. This study investigated the safety of administering TMZ to children and adolescents with brain tumors over an extended period. Extended schedules have been proven to overcome chemoresistance without any major toxicity. The toxicity of TMZ, administered at 70 mg/m/day orally for 21 consecutive days every 28 days, was assessed in children with brain tumors. A total of 156 courses of TMZ were given to 17 patients (median age 12.5 years, range 1-17 years), who were recruited into the study. Eleven patients had progressive or relapsing disease, and six patients were newly diagnosed. In this cohort no cases of toxic death or nonhematological toxicity were reported. In comparison with the 5-day schedule, thrombocytopenia and neutropenia were noted to be less frequent. Grades 3 and 4 lymphopenia occurred in 10.8 and 22.4% of courses, respectively; among the lymphopenic patients there was one case of disseminated zoster (meningoencephalitis and cutaneous involvement), one case of rotavirus gastroenteritis, and two cases of herpetic stomatitis reported. The objective response rate was 11.8%. Overall, 82.3% of patients showed stable disease. The prolonged TMZ schedule appeared to be well tolerated, with few cases of neutropenia or thrombocytopenia recorded. Nevertheless, prolonged exposure to TMZ was associated with lymphopenia and may lead to a higher rate of viral infections. [ABSTRACT FROM AUTHOR]

Purpose: To characterize and compare pharmacokinetic parameters in children and adults treated with temozolomide (TMZ) administered for 5 days in three doses daily, and to evaluate the possible relationship between AUC values and hematologic toxicity.Methods: TMZ pharmacokinetic parameters were characterized in pediatric and adult patients with primary central nervous system tumors treated with doses ranging from 120 to 200 mg/m2 per day, divided into three doses daily for 5 days. Plasma levels were measured over 8 h following oral administration in a fasting state. A total of 40 courses were studied in 22 children (mean age 10 years, range 3-16 years) and in 8 adults (mean age 30 years, range 19-54 years).Results: In all patients, a linear relationship was found between systemic exposure (AUC) and increasing doses of TMZ. Time to peak concentration, elimination half-life, apparent clearance and volume of distribution were not related to TMZ dose. No differences were seen among TMZ C(max), t(1/2), V(d) or CL/F in children compared with adults. Intra- and interpatient variability of systemic exposure were limited in both children and adults. No statistically significant differences were found between the AUCs of children who experienced grade 4 hematologic toxicity and children who did not.Conclusions: No difference appears to exist between pharmacokinetic parameters in adults and children when TMZ is administered in three doses daily. Hematologic toxicity was not related to TMZ AUC. AUC measurement does not appear to be of any use in optimizing TMZ treatment. [ABSTRACT FROM AUTHOR]

The anaplastic lymphoma kinase (ALK) gene has been found either rearranged or mutated in several neoplasms such as anaplastic large-cell lymphoma, non-small-cell lung cancer, neuroblastoma and anaplastic thyroid cancer. Medulloblastoma (MB) is an embryonic pediatric cancer arising from nervous system, a tissue in which ALK is expressed during embryonic development. We performed an ALK mutation screening in 52 MBs and we found a novel heterozygous germline deletion of a single base in exon 23 (3605delG) in a case with marked anaplasia. This G deletion results in a frameshift mutation producing a premature stop codon in exon 25 of ALK tyrosine kinase domain. We also screened three human MB cell lines without finding any mutation of ALK gene. Quantitative expression analysis of 16 out of 52 samples showed overexpression of ALK mRNA in three MBs. In the present study, we report the first mutation of ALK found in MB. Moreover, a deletion of ALK gene producing a stop codon has not been detected in human tumors up to now. Further investigations are now required to elucidate whether the truncated form of ALK may have a role in signal transduction. [ABSTRACT FROM AUTHOR]