Access to essential anticancer medicines for children and adolescents in Europe.

BACKGROUND: Essential anticancer medicines are an indispensable component of multidisciplinary treatment of paediatric malignancies. A European Society for Medical Oncology (ESMO) study reported inequalities in the availability of anticancer medicines for adult solid tumours and provided a model for the present survey. The aim of this survey was to assess the accessibility of essential medicines used in paediatric cancer patients aged 0 to 18 years across Europe from 2016 to 2018. METHODS: A list of medicines was drawn with input from the European Society for Paediatric Oncology (SIOP Europe) Clinical Research Council referring to the World Health Organization Model List of Essential Medicines for Children (WHO EMLc) 2017. A survey was sent to nominated national clinician and pharmacist rapporteurs and parent associations in up to 37 countries; answers were obtained from 34 countries. RESULTS: The full survey list contained 68 medicines, including 24 on the WHO EMLc 2017. Health professionals reported that 35% of all medicines were prescribed off-label in at least one country and that 44% were always available in >90% of countries. Only 63% of the EMLc 2017 medicines were reported as always available. The main determinant of unavailability was shortages, reported for 72% of medicines in at least one country. Out-of-pocket costs were reported in eight countries. Twenty-seven percent of orally administered medicines were never available in child-friendly formulations. Parents detailed individual efforts and challenges of facilitating ingestion of oral medicines as prescribed. Inequalities in access to pain control during procedures were reported by parents across Europe. CONCLUSIONS: Children and adolescents with cancer in Europe experience lack of access to essential medicines. Urgent actions are needed to address shortages, financial accessibility, availability of safe age-appropriate oral formulations, and pain management across Europe.

Crizotinib in c-MET- or ROS1-positive NSCLC: results of the AcSé phase II trial.

BACKGROUND: In 2013, the French National Cancer Institute initiated the AcSé program to provide patients with secure access to targeted therapies outside of their marketed approvals. Efficacy and safety was then assessed using a two-stage Simon phase II trial design. When the study design was designed, crizotinib was approved only as monotherapy for adults with anaplastic lymphoma kinase plus non-small-cell lung cancers (NSCLC). PATIENTS AND METHODS: Advanced NSCLC patients with c-MET ≥6 copies, c-MET-mutated, or ROS-1-translocated tumours were enrolled in one of the three cohorts. Patients were treated with crizotinib 250 mg twice daily. Efficacy was assessed using the objective response rate (ORR) after two cycles of crizotinib as primary outcome. Secondary outcomes included disease control rate at four cycles, best ORR, progression-free survival, overall survival, and drug tolerance. RESULTS: From August 2013 to March 2018, 5606 patients had their tumour tested for crizotinib targeted molecular alterations: 252 patients had c-MET ≥6 copies, 74 c-MET-mutation, and 78 ROS-1-translocated tumour. Finally, 25 patients in the c-MET ≥6 copies cohort, 28 in the c-MET-mutation cohort, and 37 in the ROS-1-translocation cohort were treated in the phase II trial. The ORR was 16% in the c-MET ≥6 copies cohort, 10.7% in the mutated, and 47.2% in the ROS-1 cohort. The best ORR during treatment was 32% in the c-MET-≥6 copies cohort, 36% in the c-MET-mutated, and 69.4% in the ROS-1-translocation cohort. Safety data were consistent with that previously reported. CONCLUSIONS: Crizotinib activity in patients with ROS1-translocated tumours was confirmed. In the c-MET-mutation and c-MET ≥6 copies cohorts, despite insufficient ORR after two cycles of crizotinib, there are signs of late response not sufficient to justify the development of crizotinib in this indication. The continued targeting of c-MET with innovative therapies appears justified. CLINICAL TRIAL NUMBER: NCT02034981.

[Potential role of antiangiogenic treatment in neuroblastoma]. / Neuroblastome : intérêt des traitements anti-angiogéniques.

Focus on new drug development over the last few years has yielded new agents that differ from unspecific classical chemotherapeutics and ionizing radiation, while still targeting the cancer cell itself. Antiangiogenesis is a totally distinct approach targeting the tumor's blood vessels. This concept has now found its eligibility for the treatment of several adult solid tumors: the human antivascular endothelial growth factor (VEGF) antibody bevacizumab, as well as the VEGF receptor tyrosine kinase inhibitors, sunitinib and sorafinib, have recently been licensed by the US Food and Drug Administration (FDA) and the European Medicines Agency (EMEA) for the treatment of colorectal, renal, and lung cancer. Other antiangiogenic drugs are under preclinical and early clinical evaluation. However, what do we know of the use of these drugs in pediatric solid tumors, such as sarcomas and embryonal and neuronal tumors? For some time now, neuroblastoma has been shown to be dependent on angiogenesis. However, the first preclinical data on antiangiogenic drugs in neuroblastoma have not been published until recently, and clinical trials with antiangiogenic agents in neuroblastoma treatment protocols are scarce. This review adresses current knowledge on the important role and mechanisms of angiogenesis in neuroblastoma and summarizes available preclinical and clinical results of antiangiogenic agents used to treat neuroblastoma. Our review clearly demonstrates that clinical trials are urgently needed to bring forward promising antiangiogenesis concepts in neuroblastoma therapy.

Evaluation of the Implementation of the Response Assessment in Neuro-Oncology Criteria in the HERBY Trial of Pediatric Patients with Newly Diagnosed High-Grade Gliomas.

BACKGROUND AND PURPOSE: HERBY was a Phase II multicenter trial setup to establish the efficacy and safety of adding bevacizumab to radiation therapy and temozolomide in pediatric patients with newly diagnosed non-brain stem high-grade gliomas. This study evaluates the implementation of the radiologic aspects of HERBY. MATERIALS AND METHODS: We analyzed multimodal imaging compliance rates and scan quality for participating sites, adjudication rates and reading times for the central review process, the influence of different Response Assessment in Neuro-Oncology criteria in the final response, the incidence of pseudoprogression, and the benefit of incorporating multimodal imaging into the decision process. RESULTS: Multimodal imaging compliance rates were the following: diffusion, 82%; perfusion, 60%; and spectroscopy, 48%. Neuroradiologists' responses differed for 50% of scans, requiring adjudication, with a total average reading time per patient of approximately 3 hours. Pseudoprogression occurred in 10/116 (9%) cases, 8 in the radiation therapy/temozolomide arm and 2 in the bevacizumab arm (P < .01). Increased target enhancing lesion diameter was a reason for progression in 8/86 cases (9.3%) but never the only radiologic or clinical reason. Event-free survival was predicted earlier in 5/86 (5.8%) patients by multimodal imaging (diffusion, n = 4; perfusion, n = 1). CONCLUSIONS: The addition of multimodal imaging to the response criteria modified the assessment in a small number of cases, determining progression earlier than structural imaging alone. Increased target lesion diameter, accounting for a large proportion of reading time, was never the only reason to designate disease progression.

Treatment outcome and survival in participants of phase I oncology trials carried out from 2003 to 2006 at Institut Gustave Roussy.

BACKGROUND: The oncology community usually perceives phase I oncology trials as associated with poor or limited benefits and substantial risks. There is scarce data concerning outcome and survival of patients enrolled in current phase I oncology trials. PATIENTS AND METHODS: We reviewed all phase I oncology trials conducted by investigators from the Adult Phase I Unit at Institut Gustave Roussy from 2003 to 2006. We report data concerning patient demographics, treatment outcome, toxicity, survival and type of care after trial exit. RESULTS: We analyzed 10 trials involving 180 participants. The overall response rate was 7.2%. Disease control (objective response plus stable disease) was achieved in 48.2% of patients. The rate of toxic death was 0.5%. In all, 38% of patients had at least one episode of grade 3 or 4 toxic events. The median progression-free survival and the median overall survival (OS) were 2.3 and 8.7 months, respectively. On multivariate analysis, a time between diagnosis of disease and inclusion in the phase I trial > or =24 months and evidence of disease control were statistically significant predictors of improved OS. CONCLUSION: Current phase I oncology trials are safe and are associated with clinical benefit in a substantial proportion of patients.

Prospective validation of a novel IV busulfan fixed dosing for paediatric patients to improve therapeutic AUC targeting without drug monitoring.

INTRODUCTION: Oral busulfan clearance is age-dependent and children experience a wide variability in plasma exposure. BSA- or age-based dosing is used with therapeutic drug monitoring (TDM) to reduce this variability. PURPOSE: A new intravenous (IV) dosing of busulfan (Bu) based on body weight, designed to improve AUC targeting without TDM and dose-adjustment, was prospectively evaluated. METHOD: Bu was administered as a 2 h IV infusion every 6 h over 4 days (16 administrations). Five dose levels were defined on body weight as follows: 1.0 mg/kg for <9 kg; 1.2 mg/kg for 9 to <16 kg; 1.1 mg/kg for 16-23 kg; 0.95 mg/kg for >23-34 kg; 0.80 mg/kg for >34 kg. Bu treatment was followed by Cyclophosphamide or Melphalan prior to allogeneic or autologous transplantation in 55 children aged 0.3-17.2 years (median 5.6 years). RESULTS: No difference in AUC values was observed between weight strata (mean +/- SD 1248 +/- 205 micromol.min), whereas a significant difference in Bu clearance was demonstrated. This new dosing enabled to achieve a mean exposure comparable to that in adults. At dose 1, 91% of patients achieved the targeted AUC range (900-1500 micromol.min) while no patients were underexposed. At doses 9 and 13, over 75% of patients remained within that target whilst most of the others were slightly above. Successful engraftment was achieved in all patients. In conclusion, from infants to adults this new dosing enabled, without TDM and dose adjustment, to successfully target a therapeutic AUC window.

Pleiotrophin, a candidate gene for poor tumor vasculature and in vivo neuroblastoma sensitivity to irinotecan.

In vivo neuroblastoma (NB) xenograft model, resistant to the DNA-topoisomerase I inhibitor irinotecan (CPT-11), has been established to study resistance mechanisms acquired in a therapeutic setting. Common mechanisms of resistance were not involved in this resistance. Thus, we compared the gene expression profiles of sensitive, resistant, and reverted tumors using cDNA expression arrays. Expression of selected transcripts was confirmed by quantitative real-time PCR. We found that pleiotrophin (PTN), a heparin-binding growth factor, was the only gene significantly affected: PTN gene expression was downregulated in all resistant tumors (8-14-fold) as compared to sensitive tumors, and was increased (2-4-fold) in all reverted tumors as compared to resistant tumors. PTN thus appeared to be a likely candidate gene associated with resistance to CPT-11 in this in vivo model. To investigate the direct implication of PTN in NB, we transfected two NB cell lines with RNA interferences in order to silence PTN. PTN failed to demonstrate implication in resistance to CPT-11 in vitro but could influence sensitivity to CPT-11 exclusively through an in vivo mechanism. Indeed, vasculature was significantly enhanced in resistant NB xenografts compared to sensitive and reverted xenografts, and we suggest that PTN is acting in our resistant in vivo NB model as an angiostatic factor.

Elevated plasma ferritin and busulfan pharmacodynamics during high-dose chemotherapy regimens in children with malignant solid tumors.

Hepatic veno-occlusive disease (HVOD) is a frequent complication during hematopoietic stem-cell transplantation (HSCT). A strong relationship has been demonstrated between busulfan exposure and HVOD for busulfan-cyclophosphamide and allogeneic HSCT in adults. Busulfan disposition after the first intake was studied in 77 children treated for solid malignancies with high-dose busulfan-containing regimens and autologous HSCT. Busulfan was combined with cyclophosphamide and melphalan (n=30), melphalan (n=27), and thiotepa (n=20). No relationship was observed between busulfan exposure and HVOD. In contrast, plasma ferritin at baseline was higher in patients with HVOD (750 ng/ml (20-3,110)) compared with those without HVOD (189 ng/ml (8-3,967), P=0.012). Multivariate analysis showed that a ferritin level exceeding 300 ng/ml was the only risk factor for HVOD with an odds ratio of 4.0 (confidence interval 95% (1.5-11.2), P=0.0071). A high ferritin level at baseline was explained by the diagnosis of neuroblastoma, related treatments and transfusions.

Dose finding study of oral PSC 833 combined with weekly intravenous etoposide in children with relapsed or refractory solid tumours.

PSC 833 is an effective MDR1 reversal agent in vitro, including studies with paediatric cancer cell lines such as neuroblastoma and rhabdomyosarcoma. This study was performed to determine the safety profile, dose limiting toxicity (DLT) and maximum tolerated dose (MTD) in children with solid tumours and to determine the influence of PSC 833 on the pharmacokinetics of co-administered etoposide. Each patient received one cycle of intravenous etoposide (100 mg/m2 daily for 3 days on three consecutive weeks) to document baseline pharmacokinetics, and subsequently the same schedule using a dose of 50 mg/m2 was given combined with PSC 833 given orally every 6h at a starting dose of 4 mg/kg. Thirty two eligible patients (23 male, median age 8.3 years) were enrolled. Neuroblastoma and rhabdomyosarcoma were the common disease types. Brain tumours were excluded. DLT was defined as any non-haematological grade 3-4 toxicity (common toxicity criteria) and using a specific toxicity scale for cerebellar toxicity. The MDT was defined as the first dose below which 2 or more patients per dose level experienced DLT. Grade 1-2 ataxia occurred in cohorts 2 and 3 (4 and 5 mg/kg, respectively). Three patients developed grade 3 neurotoxicity in the 6 mg/kg cohort and this defined the MTD. Six responses were observed (2 CR, 4 PR). Pharmacokinetic studies indicated that the clearance of etoposide was reduced by approximately 50% when combined with PSC 833. It is concluded that the toxicity profile and MDT is similar in both children and adults, as is the effect on etoposide metabolism. The study demonstrated the feasibility and safety of carrying out a paediatric phase 1 trial across European boundaries and acts as a model for future cooperative studies in rare cancers among children.

[Targeted therapies in pediatric oncology: a new therapeutic approach?]. / Thérapies ciblées en oncologie pédiatrique: nouvelle approche thérapeutique.

A multidisciplinary therapeutic approach has led to significant increase in survival of children with cancer, however often with a high rate of severe sequela. Better understanding in tumor cell biology and transformation process allowed to describe active tyrosine kinases (mainly growth factor receptors) as a new target for cancer treatment. This review presents 2 approaches to target receptor tyrosine kinase activity: on one hand, antibodies that target the extracellular domain, the natural ligand binding site, and on the other hand, small inhibiting molecules, such as imatinib, targeted against the activated intracellular receptor tyrosine kinase. We focus on their clinical development and current application in the treatment of childhood cancer. Targeted therapies are in full rise and new perspectives are explored, such as their association to other treatment modalities and the targeting of microenvironment. This new therapeutic approach necessitates well designed clinical trials that include relevant biomarkers to evaluate its real therapeutic potential.

Chronopharmacology of high-dose busulfan in children.

In bone marrow transplantation, high-dose busulfan is given p.o., usually every 6 h over 4 consecutive days. Since this repeated administration might alter busulfan disposition, fluctuations in busulfan plasma levels were studied over the 4-day treatment period in 21 children (median age, 5 years) with malignant solid tumors. In addition, urinary excretion of unchanged busulfan was measured every 6 h in 4 patients. Busulfan (37.5 mg/m2 for 16 doses) was given on an empty stomach at 12 p.m., 6 p.m., midnight, and 6 a.m. for 4 consecutive days, starting at 12 p.m. Trough plasma levels, i.e., concentration 6 h after each dose and just before the next one, and urinary excretion of busulfan were measured using a gas chromatography-mass spectrometry assay. Busulfan trough plasma levels exhibited a significant circadian rhythm with a higher mean level at 6 a.m. compared to that at 12 p.m., 6 p.m., and midnight. This rhythm was characterized by a double amplitude (mean +/- SD) of 42 +/- 14% and an acrophase (maximum) occurring at 5:48 a.m. +/- 115 min. In addition, once the steady state was reached, no decreasing trend was observed in any patient. Busulfan renal clearance proved to be low since only 5.4 +/- 1.2% of the given dose were excreted unchanged in urine. In the 4 patients studied, busulfan urinary excretion exhibited a significant circadian rhythm which was apparently linked to the physiological circadian rhythm in urinary output. Ten of 20 evaluable patients developed hepatic venoocclusive disease (HVOD). A significant circadian rhythm in the plasma level was found in both HVOD and non-HVOD patients with no difference between the two groups with regard to the 24-h mean, amplitude, or acrophase. Thus, the circadian changes in busulfan trough plasma levels observed at the steady state were not related to the occurrence of HVOD in these children with solid tumors. Moreover, since this rhythm was stable from day 2 to day 4, it should not compromise dose adjustment.

Dose-dependent neurotoxicity of high-dose busulfan in children: a clinical and pharmacological study.

Busulfan is known to be neurotoxic in animals and humans, but its acute neurotoxicity remains poorly characterized in children. We report here a retrospective study of 123 children (median age, 6.5 years) receiving high-dose busulfan in combined chemotherapy before bone marrow transplantation for malignant solid tumors, brain tumors excluded. Busulfan was given p.o., every 6 hours for 16 doses over 4 days. Two total doses were consecutively used: 16 mg/kg, then 600 mg/m2. The dose calculation on the basis of body surface area results in higher doses in young children than in older patients (16 to 28 mg/kg). Ninety-six patients were not given anticonvulsive prophylaxis; 7 (7.5%) developed seizures during the 4 days of the busulfan course or within 24 h after the last dosing. When the total busulfan dose was taken into account, there was a significant difference in terms of neurotoxicity incidence among patients under 16 mg/kg (1 of 57, 1.7%) and patients under 600 mg/m2 (6 of 39, 15.4%) (P less than 0.02). Twenty-seven patients were given a 600-mg/m2 busulfan total dose with continuous i.v. infusion of clonazepam; none had any neurological symptoms. Busulfan levels were measured by a gas chromatographic-mass spectrometry assay in the plasma and cerebrospinal fluid of 9 children without central nervous system disease under 600 mg/m2 busulfan with clonazepam:busulfan cerebrospinal fluid:plasma ratio was 1.39. This was significantly different (P less than 0.02) from the cerebrospinal fluid:plasma ratio previously defined in children receiving a 16-mg/kg total dose of busulfan. This study shows that busulfan neurotoxicity is dose-dependent in children and efficiently prevented by clonazepam. A busulfan dose calculated on the basis of body surface area, resulting in higher doses in young children, was followed by increased neurotoxicity, close to neurotoxicity incidence observed in adults. Since plasma pharmacokinetic studies showed a faster busulfan clearance in children than in adults, this new dose may approximate more closely the adult systemic exposure obtained after the usual 16-mg/kg total dose, with potential inferences in terms of anticancer or myeloablative effects. The busulfan dose in children and infants undergoing bone marrow transplantation should be reconsidered on the basis of pharmacokinetic studies.

Juvenile granulosa cell tumor of the ovary in children: a clinical study of 15 cases.

Juvenile granulosa cell tumor (JGCT) in children accounted for 12% of all ovarian tumors treated in the Institut Gustave-Roussy (IGR) Pediatric Department from 1967 to 1985. The median age of the 15 girls was 8 years 7 months (range, 22 months to 15 years 7 months). Precocious pseudopuberty was present in six of the seven girls under 8 years. Of the other seven girls, one developed virilization symptoms. Surgery was the first treatment in each case. According to the Wollner classification, there were six stage I, one stage II, six stage III (including four ruptured tumors), and one stage IV JGCT cases. One patient was not available for staging. An adjuvant treatment (five chemotherapy and one radiotherapy combined with chemotherapy) was administered to six patients. Eleven girls are alive and free of disease, with a median follow-up of 6 years (range, 2 to 18 years). Four girls relapsed 6 to 17 months after surgery and died. Two of these relapses occurred in bone. The prognosis for JGCT in children is favorable for the lower stages when treated with surgery, but the best treatment for extensive and recurrent disease has yet to be determined.

Combined continuous infusion etoposide with high-dose cyclophosphamide for refractory neuroblastoma: a phase II study from the Société Française d'Oncologie Pédiatrique.

PURPOSE: Patients older than 1 year with stage IV neuroblastoma who fail to achieve complete remission (CRem) have a particularly poor long-term prognosis. In an attempt to improve the outcome of these refractory patients, we tested a new drug combination. PATIENTS AND METHODS: Twenty-nine children with advanced neuroblastoma (27 stage IV and two stage III) were entered onto this phase II study. All were refractory to conventional chemotherapy and had measurable disease at the time of the trial. The regimen was a combination of high-dose cyclophosphamide (2 g/m2/d) on days 2, 3, and 4, and etoposide (VP16; 50 mg/m2/d) by continuous intravenous (IV) infusion on days 1 to 5. A pharmacokinetic study of VP16 was conducted in eight patients to determine whether the goal of persistent plasma levels between 1 and 5 micrograms/mL was achieved. RESULTS: Patients received a median of two courses, for a total of 58 courses. The median interval between each course was 32 days. In the 28 assessable patients, the overall response rate was 43%, with one CRem and 11 partial remissions (PRems). No life-threatening complication was observed in these heavily pretreated patients. The median duration of neutropenia (< 5 x 10(9)/L) was 14 days, and that of thrombocytopenia (< 50 x 10(9)/L) was 11 days. The overall incidence of sepsis was 27%. Gastrointestinal toxicity was frequent, but mild. Electrolyte disturbance with antidiuretic hormone (ADH)-like syndrome occurred in eight courses, but resolved rapidly. Grade > or = 2 hemorrhagic cystitis was observed in three courses. No cardiac toxicity was observed. There were no treatment-related deaths. Pharmacokinetic analysis showed that mean steady-state plasma levels (Css) of VP16 were greater than 1 microgram/mL during all the courses. CONCLUSION: This new drug combination appears to be effective in advanced neuroblastoma. Its toxicity remains manageable, with no life-threatening complications. Further evaluation in patients with less-advanced disease is warranted.

Pathophysiology and therapy of irinotecan-induced delayed-onset diarrhea in patients with advanced colorectal cancer: a prospective assessment.

PURPOSE: Irinotecan (CPT-11), a camptothecin derivative, has shown efficacy against colorectal cancer. Delayed-onset diarrhea is its main limiting toxicity. The aim of this study was to determine the pathophysiology of CPT-11-induced delayed-onset diarrhea and assess the efficacy of combined antidiarrheal medication in a phase II, prospective, successive-cohorts, open study. PATIENTS AND METHODS: Twenty-eight patients with advanced colorectal cancer refractory to fluorouracil (5-FU) therapy received CPT-11 350 mg/m2 every 3 weeks. The first cohort of 14 consecutive patients explored for the mechanism of diarrhea received acetorphan (a new enkephalinase inhibitor) 100 mg three times daily; the second 14-patient cohort received, in addition to acetorphan, loperamide 4 mg three times daily. Before treatment, and if late diarrhea occurred, patients underwent colon mucosal biopsies for CPT-11 and topoisomerase I levels; intestinal transit time; fecalogram; fat and protein excretion; alpha1-antitrypsin clearance; D-xylose test; blood levels for vasoactive intestinal polypeptide, glucagon, gastrin, somatostatin, prostaglandin E2, and carboxylesterase; CPT-11/SN-38 and SN-38 glucuronide pharmacokinetics; and stool cultures. RESULTS: Delayed-onset diarrhea occurred during the first three treatment cycles in 23 patients (82%). Electrolyte fecal measurements showed a negative or small osmotic gap in nine of nine patients and an increased alpha1-antitrypsin clearance in six of six patients. There were no modifications in stool cultures or hormonal dysfunction. Four of 11 patients (36%) with delayed-onset diarrhea in the first cohort responded to acetorphan, whereas nine of 10 patients (90%) responded to the combination of acetorphan and loperamide (P < .02). CONCLUSION: CPT-11-induced delayed-onset diarrhea is caused by a secretory mechanism with an exudative component. Early combined treatment with loperamide and acetorphan seems effective in controlling the diarrheal episodes.

Conduct of phase I trials in children with cancer.

PURPOSE AND METHODS: Future progress in the care of children with cancer requires appropriate evaluations of promising new agents for pediatric indications, beginning with well-conducted phase I trials. This report summarizes current guidelines for the conduct of pediatric phase I trials and represents a consensus between American and European investigators. The primary objective of pediatric phase I trials is to define safe and appropriate doses and schedules of new agents that can subsequently be used in phase II trials to test for activity against specific childhood malignancies. Prioritization of agents for evaluation in children is critical, since many more investigational agents are evaluated in adult patients than can be systematically evaluated in children. Considerations used in prioritizing agents include activity in xenograft models, novel mechanism of action, favorable drug-resistance profile, and activity observed in adult trials of the agent. RESULTS AND CONCLUSION: Distinctive characteristics of pediatric phase I trials, in comparison to adult phase I trials, include the necessity for multiinstitutional participation and their higher starting dose (typically 80% of the adult maximum-tolerated dose [MTD]), both of which reflect the relative unavailability of appropriate patients. The application of uniform eligibility criteria and standard definitions for MTD and dose-limiting toxicity (DLT) help to assure that pediatric phase I trials are safely conducted and reliably identify appropriate doses and schedules of agents for phase II evaluation. Where possible, pediatric phase I trials also define the pharmacokinetic behavior of new agents in children.

Temozolomide in malignant gliomas of childhood: a United Kingdom Children's Cancer Study Group and French Society for Pediatric Oncology Intergroup Study.

PURPOSE: To determine the response rate of the malignant gliomas of childhood to an oral, daily schedule of temozolomide. PATIENTS AND METHODS: A multicenter, phase II evaluation of an oral, daily schedule of temozolomide (200 mg/m(2) on 5 consecutive days) was undertaken in children with relapsed or progressive, biopsy-proven, high-grade glioma (arm A) and progressive, diffuse, intrinsic brainstem glioma (arm B). Evidence of activity was defined by radiologic evidence of a sustained reduction in tumor size on serial magnetic resonance imaging scans. RESULTS: Fifty-five patients were recruited (34 to arm A and 21 to arm B) and received 215 cycles of chemotherapy. Grade 3/4 thrombocytopenia was the most frequent toxic event (7% of cycles). Prolonged myelosuppression resulted in significant treatment delays and dose reductions (17% and 22% of cycles, respectively). Two toxic deaths were documented and were related to myelosuppression and sepsis in one patient and pneumonia in a second. The overall (best) response rate was 12% for arm A (95% confidence interval [CI], 3 to 28 in the study cohort, and 2 to 31 for eligible patients) and 5% and 6%, respectively, for arm B (95% CI, 0 to 26 in the study cohort, and 0 to 27 for eligible patients). Stabilization of disease was also documented and was most noteworthy for brainstem gliomas, where two patients achieved both radiologic static disease and discontinued steroid medication. CONCLUSION: Despite moderate toxicity, objective response rates to temozolomide have been low, indicating that temozolomide has minimal activity in the high-grade gliomas of childhood.

In vivo potentiation of radiation response by topotecan in human rhabdomyosarcoma xenografted into nude mice.

The lack of new highly efficacious drugs for cancer treatment promotes the search for innovative therapeutic modalities. The authors reported the results leading to the definition of parameters needed to demonstrate a possible radiopotentiation by topotecan (TPT) on two representative human rhabdomyosarcomas (RMSs) xenografted into nude mice. Experimental studies of radiopotentiation with different doses of topotecan showed that concomitant association of topotecan and RT for 5 consecutive days provided a synergistic therapeutic effect. Response rates were statistically higher with the radiochemotherapeutic combination (P < 0.001). Efficacy enhancement factors of this combination compared with the sum of the antitumoral activity of these treatments separately administrated were 1.54 and 1.60, respectively, on both rhabdomyosarcomas. Moreover, the efficiency of the combination of radiotherapy at the dose of 20 Gy with topotecan (12.5 mg/kg) was not statistically different from that of radiotherapy at the dose of 40 Gy. According to microscopy results, the analyses performed at different periods after topotecan treatment alone, radiotherapy alone, and their combination seemed to show that tumoral repopulation by malignant cells is as fast as the dose of radiotherapy and/or topotecan is low. Furthermore, lesions observed with the dose of 40 Gy were similar to those obtained with the association of topotecan at the dose of 12.5 mg/kg and radiotherapy at the dose of 20 Gy. In conclusion, all clinical and pathological results are consistent with a radiopotentiation effect of topotecan on the two xenografted human rhabdomyosarcomas and are currently leading to the design of clinical studies.