Phase I trial of VNP40101M (Cloretazine) in children with recurrent brain tumors: a pediatric brain tumor consortium study.

PURPOSE: VNP40101M (Cloretazine), a novel DNA alkylating agent, was evaluated in a phase I study in children with recurrent brain tumors. EXPERIMENTAL DESIGN: VNP40101M was given i.v. daily for 5 consecutive days every 6 weeks for up to eight cycles. Dose escalation was done independently in patients stratified based on intensity of prior therapy (moderately pretreated, stratum I; heavily pretreated, stratum II). Correlative studies included pharmacokinetics and measurement of O(6)-alkylguanine-DNA alkyl transferase levels in peripheral blood mononuclear cells before and after treatment. RESULTS: Forty-one eligible patients (stratum I, 19; stratum II, 22) were enrolled on this study. The dose-limiting toxicity in 35 evaluable patients was myelosuppression, which occurred in 4 of 16 patients in stratum I and 3 of 19 patients in stratum II. Pharmacokinetic studies showed a median terminal half-life of 30 min (range, 14-39.5). The maximum tolerated dose in stratum I and II were 45 and 30 mg/m(2)/d daily for 5 days every 6 weeks, respectively. Peripheral blood mononuclear cells alkylguanine alkyl transferase levels did not decrease significantly after VNP40101M treatment. Central imaging review confirmed that three patients had stable disease for a median of 45 weeks (range, 37-61+) after therapy. CONCLUSIONS: The recommended dose of VNP40101M for phase II studies in children with brain tumors is 45 mg/m(2)/d in moderately pretreated and 30 mg/m(2)/d in heavily pretreated patients when administered for 5 consecutive days every 6 weeks.

Phase I study of everolimus in pediatric patients with refractory solid tumors.

PURPOSE: To determine the maximum-tolerated dose (MTD), dose-limiting toxicities (DLTs), and pharmacokinetic and pharmacodynamic properties of the mammalian target of rapamycin (mTOR) inhibitor, everolimus, in children with refractory or recurrent solid tumors. PATIENTS AND METHODS: Everolimus was administered orally at a daily dose of 2.1, 3, 5, or 6.5 mg/m2 in cohorts of three to six patients per dosage level. Pharmacokinetic and pharmacodynamic studies were performed during the first course. The phosphorylation status of various components of the mTOR signal pathway was assessed in peripheral-blood mononuclear cells (PBMCs) isolated from treated patients. RESULTS: There were 26 patients enrolled; 18 were assessable. DLTs included diarrhea (n = 1), mucositis (n = 1), and elevation of ALT (n = 1) at 6.5 mg/m2. At the MTD of 5 mg/m2, the median everolimus clearance was 15.2 L/h/m2, with a plasma everolimus concentration-time area under the curve (AUC) from 0 to infinity of 239.6 ng/mL x h. Significant inhibition of mTOR pathway signaling was observed in PBMCs from patients achieving AUCs 200 ng/mL x h, equivalent to dosages of 3 to 5 mg/m2 of everolimus. No objective tumor responses were observed. CONCLUSION: Continuous, orally administered everolimus is well tolerated in children with recurrent or refractory solid tumors and demonstrates similar pharmacokinetic properties to those observed in adults. Everolimus significantly inhibits the mTOR signaling pathway in children at the MTD. The recommended phase II dose in children with solid tumors is 5 mg/m2.

UGT1A1 promoter genotype correlates with SN-38 pharmacokinetics, but not severe toxicity in patients receiving low-dose irinotecan.

PURPOSE: To study the association between UDP-glucuronosyltransferase 1A1 (UGT1A1) genotypes and severe toxicity as well as irinotecan disposition in pediatric patients with solid tumors receiving low-dose, protracted irinotecan (15 to 75 mg/m2 daily for 5 days for 2 consecutive weeks). PATIENTS AND METHODS: Seventy-four patients on five institutional clinical trials received irinotecan (15 to 75 mg/m2) daily intravenously or orally for 5 days for 2 consecutive weeks. Genomic DNA was genotyped for UGT1A1*28, and patients were designated as 6/6, 6/7, or 7/7 depending on the number of TA repeats in the UGT1A1 promoter region. Patients were evaluated for gastrointestinal and hematologic toxicity, as well as baseline and maximal serum bilirubin levels. Toxicity and pharmacokinetic results were evaluated during courses 1 and 2 of irinotecan therapy. RESULTS: The frequencies of 6/6, 6/7, and 7/7 genotypes were 27 (36.5%), 36 (48.6%), and 9 (12.2%) of 74 patients, respectively. Patients with 7/7 genotype had a statistically greater baseline total bilirubin than patients with 6/6 or 6/7 genotype (P = .005). UGT1A1*28 genotype was not associated with grade 3 and 4 neutropenia (P = .21 for course 1; P = .23 for course 2) or diarrhea (P = .176 for course 1; P = .87 for course 2). However, patients with the 7/7 genotype tended to have higher SN-38 area under the plasma time-concentration curve (AUC) values and lower SN-38G/SN-38 AUC ratios. CONCLUSION: Severe toxicity was not increased in pediatric patients with the 7/7 genotype when treated with a low-dose protracted schedule of irinotecan. Therefore, UGT1A1 genotyping is not a useful prognostic indicator of severe toxicity for patients treated with this irinotecan dosage and schedule.

Determination of Cloretazine (VNP40101M) and its active metabolite (VNP4090CE) in human plasma by liquid chromatography electrospray tandem mass spectrometry (LC-ESI-MS/MS).

A sensitive method for the determination of Cloretazine (VNP40101M) and its metabolite (VNP4090CE) with an internal standard (ISTD) in human plasma was developed using high-performance liquid chromatographic separation with tandem mass spectrometric detection. Acidified plasma samples (500 microL) were prepared using solid phase extraction (SPE) columns, and 25 microL of the reconstituted sample was injected onto an Ascentis C18 HPLC column (3 microm, 5 cmx2.1 mm) with an isocratic mobile phase. Analytes were detected with an API-3000 LC-MS/MS System at unit (Q1) and low (Q3) resolution in negative multiple reaction monitoring mode: m/z 249.0 (precursor ion) to m/z 114.9 (product ion) for both Cloretazine (at 3.64 min) and VNP4090CE (at 2.91 min), and m/z 253.0 (precursor ion) to m/z 116.9 (product ion) for the ISTD. The mean recovery for Cloretazine (VNP40101M) and its metabolite (VNP4090CE) was greater than 87% with a lower limit of quantification of 1.0 ng/mL for Cloretazine (S/N=9.7, CV

Plasma and cerebrospinal fluid pharmacokinetics of erlotinib and its active metabolite OSI-420.

PURPOSE: To report cerebrospinal fluid (CSF) penetration of erlotinib and its metabolite OSI-420. EXPERIMENTAL DESIGN: Pharmacokinetic measurements were done in plasma (days 1, 2, 3, and 8 of therapy) and, concurrently, in plasma and CSF (before and at 1, 2, 4, 8, and 24 h after dose on day 34 of therapy) in an 8-year-old patient diagnosed with glioblastoma who received local irradiation and oral erlotinib in a phase I protocol. CSF samples were collected from a ventriculoperitoneal shunt, which was externalized because of infection. Erlotinib concentrations were determined by liquid chromatography/mass spectrometry. CSF penetration of erlotinib and OSI-420 were estimated by a compartmental model and by calculating the ratio of CSF to plasma 24-h area under concentration-time curve (AUC(0-24)). RESULTS: This patient was assigned to receive erlotinib at a dose level of 70 mg/m(2), but the actual daily dose was 75 mg (78 mg/m(2)). Erlotinib and OSI-420 plasma pharmacokinetic variables on days 8 and 34 overlapped to suggest that steady state had been reached. Whereas erlotinib and OSI-420 AUC(0-24) in plasma on day 34 were 30,365 and 2,527 ng h/mL, respectively, the correspondent AUC(0-24) in the CSF were 2,129 and 240 ng h/mL, respectively. Erlotinib and OSI-420 CSF penetration were 7% and approximately 9%, respectively, using both estimate methods. The maximum steady-state CSF concentration of erlotinib was approximately 130 ng/mL (325 nmol/L). CONCLUSIONS: The plasma pharmacokinetics of erlotinib in this child overlapped with results described in adults. Oral administration of erlotinib achieves CSF concentrations comparable with those active against several cancer cell lines in preclinical models.