Birgit Geoerger

R1507, a Monoclonal Antibody to the Insulin-Like Growth Factor 1 Receptor in Patients With Recurrent or Refractory Ewing Sarcoma Family of Tumors: Results of a Phase II Sarcoma Alliance for Research through Collaboration Study

PURPOSE The type 1 insulin-like growth factor 1 receptor (IGF-1R) has been implicated in the pathogenesis of the Ewing sarcoma family of tumors (ESFT). We conducted a multicenter phase II study of the fully human IGF-1R monoclonal antibody R1507 in patients with recurrent or refractory ESFT. PATIENTS AND METHODS Patients ≥ 2 years of age with refractory or recurrent ESFT received R1507 at doses of 9 mg/kg intravenously one a week or 27 mg/kg intravenously every three weeks. Response was measured by using WHO criteria. Tumor imaging was performed every 6 weeks for 24 weeks and then every 12 weeks. RESULTS From December 2007 through April 2010, 115 eligible patients from 31 different institutions were enrolled. The median age was 25 years (range, 8 to 78 years). The location of the primary tumor was bone in 57% of patients and extraskeletal in 43% of patients. A total of 109 patients were treated with R1507 9 mg/kg/wk, and six patients were treated with 27 mg/kg/3 wk. The overall complete response/partial response rate was 10% (95% CI, 4.9% to 16.5%). The median duration of response was 29 weeks (range, 12 to 94 weeks), and the median overall survival was 7.6 months (95% CI, 6 to 9.7 months). Ten of 11 responses were observed in patients who presented with primary bone tumors (P = .016). The most common adverse events of grades 3 to 4 were pain (15%), anemia (8%), thrombocytopenia (7%), and asthenia (5%). CONCLUSION R1507 was a well-tolerated agent that had meaningful and durable benefit in a subgroup of patients with ESFT. The identification of markers that are predictive of a benefit is necessary to fully capitalize on this approach.

Comparative Measurements of Hypoxia in Human Brain Tumors Using Needle Electrodes and EF5 Binding

Hypoxia is known to be an important prognostic marker in many human cancers. We report the use of two oxygen measurement techniques in human brain tumors and compare these data with semiquantitative histological end points. Oxygenation was measured using the Eppendorf needle electrode and/or EF5 binding in 28 brain tumors. These data were compared with necrosis, mitosis, and endothelial proliferation. In some tumors, absolute EF5 binding was converted to tissue pO2 based on in vitro calibrations. Eppendorf electrode readings could not be used to identify WHO grade 1/2 versus WHO grade 3/4 tumors, they could not differentiate grade 3 versus grade 4 glial-derived neoplasms, nor did they correlate with necrosis or endothelial proliferation scores. EF5 binding increased as the tumor grade increased and was significantly associated with necrosis and endothelial proliferation. There was no statistically significant correlation between the two hypoxia detection techniques, although both methods indicated similar absolute ranges of tissue pO2. There was substantial inter- and intratumoral heterogeneity of EF5 binding in WHO grade 4 glial neoplasms. The majority of cells in glial-derived tumor had levels of hypoxia that were mild to moderate (defined herein as 10% to 0.5% pO2) rather than severe (defined as approximately 0.1% pO2). Immunohistochemical detection of EF5 binding tracks histological parameters in adult brain tumors, with increased binding associated with increasing necrosis and endothelial proliferation. The proportion of moderately to severely hypoxic cells is relatively low, even in the high-grade tumors. Human brain tumors are dominated by oxic to moderately hypoxic cells.

Stereotactic biopsy of diffuse pontine lesions in children

OBJECT Empirical radiotherapy is the current treatment for children with diffuse pontine lesions that have imaging characteristics of an infiltrative malignant astrocytoma. The use of chemotherapeutic agents is, however, currently under investigation in the treatment of these tumors. To be included into a trial, patients need a definitive histological diagnosis. The authors present their prospective study of the stereotactic biopsy of these lesions during a 4-year period. METHODS A suboccipital, transcerebellar approach was used to obtain biopsy samples in 24 children. RESULTS Two patients suffered deficits. Both had a transient (< 2 months) new cranial nerve palsy; one of these patients also experienced an exacerbation of a preoperative hemiparesis. No patient died during the perioperative period. A histological diagnosis was made in all 24 patients as follows: 22 had a malignant infiltrative astrocytoma, one had a low-grade astrocytoma, and one had a pilocytic astrocytoma. The diagnosis of the latter two patients affected the initial treatment after the biopsy. CONCLUSIONS The findings of this study imply that stereotactic biopsy sampling of a diffuse pontine tumor is a safe procedure, is associated with minimal morbidity, and has a high diagnostic yield. A nonmalignant tumor was identified in two of the 24 patients in whom the imaging findings were characteristic of a malignant infiltrative astrocytoma. With the advent of new treatment protocols, stereotactic biopsy sampling, which would allow specific tumor characterization of diffuse pontine lesions, may become standard.

Preliminary Efficacy of the Anti-Insulin–Like Growth Factor Type 1 Receptor Antibody Figitumumab in Patients With Refractory Ewing Sarcoma

PURPOSE Patients with Ewing sarcoma (ES) with metastases and those who relapse fare poorly and receive therapies that carry significant toxicity. This phase 1/2 study was conducted to evaluate the efficacy of figitumumab in advanced ES. PATIENTS AND METHODS Patients with sarcoma 10 to 18 years old were enrolled in two dose escalation cohorts (20 and 30 mg/Kg intravenously every 4 weeks) in the phase 1 portion of the study. Patients with ES 10 years old or older were enrolled in the phase 2 portion of the study. The primary phase 2 objective was objective response rate (ORR). RESULTS Thirty-one patients with ES (n = 16), osteosarcoma (n = 11), or other sarcomas (n = 4) were enrolled in the phase 1 portion of the study. Dose escalation proceeded to 30 mg/kg every 4 weeks with no dose-limiting toxicity identified. In the phase 2 portion of the study, 107 patients with ES received figitumumab at 30 mg/kg every 4 weeks for a median of 2 cycles (range, 1 to 16). Sixty three percent of phase 2 patients had received at least three prior treatment regimens. Of 106 evaluable patients, 15 had a partial response (ORR, 14.2%) and 25 had stable disease. Median overall survival was 8.9 months. Importantly, patients with a pretreatment circulating free insulin-like growth factor (IGF) -1 lower than 0.65 ng/mL (n = 14) had a median OS of 3.6 months, whereas those with a baseline free IGF-1 ≥ 0.65 ng/mL (n = 84) had a median OS of 10.4 months (P < .001). CONCLUSION Figitumumab had modest activity as single agent in advanced ES. A strong association between pretreatment serum IGF-1 and survival benefit was identified.

Mesenchymal Transition and PDGFRA Amplification/Mutation Are Key Distinct Oncogenic Events in Pediatric Diffuse Intrinsic Pontine Gliomas

Diffuse intrinsic pontine glioma (DIPG) is one of the most frequent malignant pediatric brain tumor and its prognosis is universaly fatal. No significant improvement has been made in last thirty years over the standard treatment with radiotherapy. To address the paucity of understanding of DIPGs, we have carried out integrated molecular profiling of a large series of samples obtained with stereotactic biopsy at diagnosis. While chromosomal imbalances did not distinguish DIPG and supratentorial tumors on CGHarrays, gene expression profiling revealed clear differences between them, with brainstem gliomas resembling midline/thalamic tumours, indicating a closely-related origin. Two distinct subgroups of DIPG were identified. The first subgroup displayed mesenchymal and pro-angiogenic characteristics, with stem cell markers enrichment consistent with the possibility to grow tumor stem cells from these biopsies. The other subgroup displayed oligodendroglial features, and appeared largely driven by PDGFRA, in particular through amplification and/or novel missense mutations in the extracellular domain. Patients in this later group had a significantly worse outcome with an hazard ratio for early deaths, ie before 10 months, 8 fold greater that the ones in the other subgroup (p = 0.041, Cox regression model). The worse outcome of patients with the oligodendroglial type of tumors was confirmed on a series of 55 paraffin-embedded biopsy samples at diagnosis (median OS of 7.73 versus 12.37 months, p = 0.045, log-rank test). Two distinct transcriptional subclasses of DIPG with specific genomic alterations can be defined at diagnosis by oligodendroglial differentiation or mesenchymal transition, respectively. Classifying these tumors by signal transduction pathway activation and by mutation in pathway member genes may be particularily valuable for the development of targeted therapies.

Population Pharmacokinetics and Pharmacogenetics of Imatinib in Children and Adults

Purpose: The aim of this study was to explore the effect of several demographic, biological, and pharmacogenetic covariates on the disposition of imatinib and its main metabolite (CGP74588) in both adults and children. Experimental Design: Thirty-three children with solid malignancies included in a phase II exploratory study and 34 adults with gastrointestinal stromal tumors received 340 mg/m2 and 400 mg imatinib, respectively. Plasma imatinib and CGP74588 concentrations observed on day 1 and at steady-state were analyzed by a population pharmacokinetic method (NONMEM) to evaluate the effect of age, body weight, age, sex, albuminemia, plasma α1-acid glycoprotein (AGP), and eight polymorphisms corresponding to ABCB1, ABCG2, CYP3A4, CYP3A5, and AGP (pharmacogenetic data available for 46 of 67 patients). Results: Analysis of the whole data set in 67 patients showed that apparent clearance (CL/F) of imatinib was positively correlated with body weight and albuminemia and negatively with AGP. By considering these three covariates, the interindividual variability on CL/F decreased from 47% to 19%. The apparent clearance of CGP74588 was similarly dependent on both body weight and AGP and significantly lower (30% reduction) at steady-state. By adding genotype status to the final covariate imatinib model, a 22% reduction in CL/F was observed in heterozygous compared with wild-type patients corresponding to ABCG2 c.421C>A (P < 0.05). Conclusions: By considering morphologic and biological covariates, a unique covariate model could be used to accurately describe imatinib pharmacokinetics in patients ages 2 to 84 years. Morphologic and biological characteristics have a stronger influence than pharmacogenetics on imatinib pharmacokinetics.

Innovative Therapies for Children with Cancer pediatric phase I study of erlotinib in brainstem glioma and relapsing/refractory brain tumors

This multicenter phase I study aimed to establish the recommended dose (RD) of the epidermal growth factor receptor (EGFR) inhibitor erlotinib, given as monotherapy or with radiotherapy to children with malignant brain tumors. Group 1 included patients with refractory or relapsing brain tumors receiving erlotinib alone, and group 2 included newly diagnosed patients with brainstem gliomas receiving radiotherapy and erlotinib. A conventional 3 + 3 dose escalation and a continual reassessment method, respectively, were utilized in 4 dose levels: 75, 100, 125, and 150 mg/m² per day. Fifty-one children were enrolled (30 and 21, respectively); 50 received treatment. The RD of erlotinib was 125 mg/m² per day as monotherapy or in combination with radiotherapy. Overall, 230 adverse events in 44 patients were possibly treatment related (216, grades 1 and 2; 9, grade 3; 1, grade 4; 4, grade 5). Dermatologic and neurologic symptoms were common; intratumoral hemorrhage was confirmed in 3 patients. In group 1, 8 of 29 patients (28%) had stable disease with tumor regression approaching 50% in a malignant glioma and an anaplastic oligoastrocytoma. In group 2, overall survival was 12.0 months. EGFR overexpression by immunohistochemistry was found in 17 of 38 (45%) tumor samples analyzed, with a partial gain of 7p11.2 in 1 glioblastoma; phosphate and tensin homolog loss was frequent in brainstem glioma (15 of 19). Mean (95% CI) apparent clearance and volume of distribution for erlotinib were 4.0 L/h (3.4-4.5 L/h) and 98.6 L (69.8-127.0 L), respectively, and were independent of the dose level; mean half-life was 16.6 hours. Thus, erlotinib 125 mg/m² per day has an acceptable tolerability profile in pediatric patients with brain tumors and can be combined with radiotherapy.

Phase II trial of temsirolimus in children with high-grade glioma, neuroblastoma and rhabdomyosarcoma☆

PURPOSE A phase II study of temsirolimus was conducted in children and adolescents with high-grade glioma, neuroblastoma or rhabdomyosarcoma. PATIENTS AND METHODS Temsirolimus 75 mg/m(2) was administered once weekly until disease progression or intolerance. Using the Simon 2-stage design, further enrolment in each disease cohort required ≥ 2 objective responses within the first 12 weeks for the first 12 evaluable patients (those who received ≥ 3 temsirolimus doses). RESULTS Fifty-two heavily pretreated patients with relapsed (12%) or refractory (88%) disease, median age 8 years (range 1-21 years), were enroled and treated. One patient with neuroblastoma achieved confirmed partial response within the first 12 weeks; thus, none of the 3 cohorts met the criterion for continued enrolment. Disease stabilisation at week 12 was observed in 7 of 17 patients (41%) with high-grade glioma (5 diffuse pontine gliomas, 1 glioblastoma multiforme and 1 anaplastic astrocytoma), 6 of 19 (32%) with neuroblastoma and 1 of 16 (6%) with rhabdomyosarcoma (partial response confirmed at week 18). In the three cohorts, median duration of stable disease or better was 128, 663 and 75 d, respectively. The most common treatment-related adverse events were thrombocytopaenia, hyperlipidaemia and aesthenia. Pharmacokinetic findings were similar to those observed in adults. CONCLUSIONS Temsirolimus administered weekly at the dose of 75 mg/m(2) did not meet the primary objective efficacy threshold in children with high-grade glioma, neuroblastoma or rhabdomyosarcoma; however, meaningful prolonged stable disease merits further evaluation in combination therapy.

Vemurafenib in pediatric patients with BRAFV600E mutated high-grade gliomas

We present three pediatric patients with BRAFV600E mutant high‐grade gliomas treated by vemurafenib on a nominative authorization level at our institution. One patient with anaplastic ganglioglioma experienced confirmed partial tumor response and significant clinical improvement and she is alive 20 months after start of treatment. A second patient with ganglioglioma responded transiently to re‐introduction of vemurafenib after immunotherapy. Pharmacokinetic studies suggest that maximum concentration and exposure of vemurafenib at steady‐state is dose‐dependent and similar in children to that reported in adults. These cases suggest that BRAFV600 is an oncogenic driver in pediatric gliomas. Further exploration in clinical studies is ongoing. Pediatr Blood Cancer 2014;61:1101–1103.

Potentiation of radiation therapy by the oncolytic adenovirus dl1520 (ONYX-015) in human malignant glioma xenografts

In spite of aggressive surgery, irradiation and/or chemotherapy, treatment of malignant gliomas remains a major challenge in adults and children due to high treatment failure. We have demonstrated significant cell lysis and antitumour activity of the E1B-55 kDa-gene-deleted adenovirus ONYX-015 (dl1520, CI-1042; ONYX Pharmaceuticals) in subcutaneous human malignant glioma xenografts deriving from primary tumours. Here, we show the combined efficacy of this oncolytic therapy with radiation therapy. Total body irradiation (5 Gy) of athymic nude mice prior to intratumoral injections of ONYX-015 1 × 108 PFU daily for 5 consecutive days yielded additive tumour growth delays in the p53 mutant xenograft IGRG88. Radiation therapy was potentiated in the p53 functional tumour IGRG121 with a ‘subtherapeutic’ dose of 1 × 107 PFU daily for 5 consecutive days, inducing significant tumour growth delay, 90% tumour regression and 50% tumour-free survivors 4 months after treatment. These potentiating effects were not due to increased adenoviral infectivity or replication. Furthermore, cell lysis and induction of apoptosis, the major mechanisms for adenoviral antitumour activity, did not play a major role in the combined treatment strategy. Interestingly, the oncolytic adenovirus seemed to accelerate radiation-induced tumour fibrosis. Potentiating antitumour activity suggests the development of this combined treatment for these highly malignant tumours.