Helen Wheeler

Phase II study of thalidomide in the treatment of recurrent glioblastoma multiforme.

Treatment options and prognosis remains poor for patients with recurrent glioblastoma multiforme. These tumors are highly vascularised and over express angiogenic factors such as vascular endothelial growth factor and may potentially be responsive to antiangiogenic therapies. We present the results of a phase II trial of Thalidomide, an antiangiogenic agent, in the treatment of recurrent glioblastoma multiforme. Patients were treated with 100 mg/day of Thalidomide, increased at weekly intervals by 100 mg to a maximum tolerated dose of 500 mg/d.Forty-two patients were enrolled, with 38 patients being assessable for response and 39 for toxicity. Two patients (5%) achieved a partial response and 16 (42%) had stable disease. The median survival was 31 weeks and the 1-year survival was 35%. Patients who had a partial response or stable disease had either a stabilisation or improvement in quality of life scores or performance status. Overall Thalidomide was well tolerated with no grade 4 toxicities and no treatment related deaths. The median maximum tolerated dose was 300 mg/day. The most common toxicity was fatigue to which patients developed tachyphylaxis. There was no correlation demonstrated with plasma vascular endothelial growth factor levels and response or survival.Thalidomide is a well-tolerated drug that may have some activity in the treatment of recurrent glioblastoma. Optimum dosing with antiangiogenic agents is currently under investigation. Chronic low dose therapy may be required to see conventional responses or improvements in time to progression. The dose required to achieve optimal biological impact may be better defined once we have established reliable surrogate endpoints.

Intertumoral Heterogeneity within Medulloblastoma Subgroups

While molecular subgrouping has revolutionized medulloblastoma classification, the extent of heterogeneity within subgroups is unknown. Similarity network fusion (SNF) applied to genome-wide DNA methylation and gene expression data across 763 primary samples identifies very homogeneous clusters of patients, supporting the presence of medulloblastoma subtypes. After integration of somatic copy-number alterations, and clinical features specific to each cluster, we identify 12 different subtypes of medulloblastoma. Integrative analysis using SNF further delineates group 3 from group 4 medulloblastoma, which is not as readily apparent through analyses of individual data types. Two clear subtypes of infants with Sonic Hedgehog medulloblastoma with disparate outcomes and biology are identified. Medulloblastoma subtypes identified through integrative clustering have important implications for stratification of future clinical trials.

Amelioration of experimental cisplatin and paclitaxel neuropathy with glutamate

A major toxic effect of the chemotherapeutic agents paclitaxel and cisplatin is peripheral neuropathy. We report the use of a rat model of cytotoxic neuropathy to evaluate the role of glutamate as a possible neuroprotectant for these two drugs. Neuropathy was manifest as gait disturbance in 100% of paclitaxel treated animals after 2 weeks and 100% of cisplatin treated animals after 8 weeks. Significant elevations of mean tail-flick threshold, a measure of sensory impairment, were observed in animals treated with both cytotoxics. Impaired rota-rod performance was observed in both light and dark with paclitaxel, indicating motor neuropathy. There was a trend towards impairment in the dark for cisplatin, suggesting proprioceptive loss. In cytotoxic treated animals supplemented with oral sodium glutamate (approx. 500 mg/kg/day in drinking water) from 24 h before chemotherapy, there was a significant delay in time to onset of gait disturbance allowing significantly higher mean doses to be tolerated. Mean tail-flick and rota-rod scores were unchanged from baseline for both drugs. Glutamate therefore protected against both sensory and motor neuropathy. Similar doses of glutamate did not impair the cytotoxic efficacy of paclitaxel or cisplatin against a transplantable rat mammary adenocarcinoma grown subcutaneously in rats. Our findings suggest that glutamate warrants clinical trial as a neuroprotectant in patients receiving paclitaxel or cisplatin.

Presence of alternative lengthening of telomeres mechanism in patients with glioblastoma identifies a less aggressive tumor type with longer survival.

Patients with glioblastoma (GBM) have variable clinical courses, but the factors that underlie this heterogeneity are not understood. To determine whether the presence of the telomerase-independent alternative lengthening of telomeres (ALTs) mechanism is a significant prognostic factor for survival, we performed a retrospective analysis of 573 GBM patients. The presence of ALT was identified in paraffin sections using a combination of immunofluorescence for promyelocytic leukemia body and telomere fluorescence in situ hybridization. Alternative lengthening of telomere was present in 15% of the GBM patients. Patients with ALT had longer survival that was independent of age, surgery, and other treatments. Mutations in isocitrate dehydrogenase (IDH1mut) 1 frequently accompanied ALT, and in the presence of both molecular events, there was significantly longer overall survival. These data suggest that most ALT+ tumors may be less aggressive proneural GBMs, and the better prognosis may relate to the set of genetic changes associated with this tumor subtype. Despite improved overall survival of patients treated with the addition of chemotherapy to radiotherapy and surgery, ALT and chemotherapy independently provided a survival advantage, but these factors were not found to be additive. These results suggest a critical need for developing new therapies to target these specific GBM subtypes.

DRUG RESISTANCE MECHANISMS AND MRP EXPRESSION IN RESPONSE TO EPIRUBICIN TREATMENT IN A HUMAN LEUKAEMIA CELL LINE

A drug resistant series of sublines were developed by treating the human leukaemia CCRF-CEM cell line with 16-1000 ng/ml of the anthracycline, epirubicin. The sublines developed resistance in two stages, neither involving detectable levels of P-glycoprotein. Treatment with up to 50 ng/ml epirubicin produced sublines with cross resistance limited to the anthracyclines and etoposide. Treatment with 100-1000 ng/ml epirubicin produced sublines with increased expression of the mrp gene, increased resistance to the anthracyclines and etoposide, additional cross resistance to vincristine and colchicine, decreased drug accumulation and reversal of resistance by verapamil and by buthionine sulphoximine (BSO; an inhibitor of glutathione synthesis). Our results indicate an interaction between MRP and glutathione metabolism as a mechanism for multidrug resistance.

Molecular heterogeneity in glioblastoma: potential clinical implications.

Glioblastomas, (grade 4 astrocytomas), are aggressive primary brain tumors characterized by histopathological heterogeneity. High-resolution sequencing technologies have shown that these tumors also feature significant inter-tumoral molecular heterogeneity. Molecular subtyping of these tumors has revealed several predictive and prognostic biomarkers. However, intra-tumoral heterogeneity may undermine the use of single biopsy analysis for determining tumor genotype and has implications for potential targeted therapies. The clinical relevance and theories of tumoral molecular heterogeneity in glioblastoma are discussed.

Modulation of tissue factor on human monocytes by cisplatin and adriamycin

Coagulation disorders have been associated with the use of chemotherapeutic drugs. Pharmacological doses of cisplatin and adriamycin directly induced low levels of procoagulant on normal human blood monocytes and on a human myelomonocytic cell line, RC2a. Activity was maximal after 24 h and was not due to cell lysis as increasing drug doses which decreased cell viability were less effective. Procoagulant induction was markedly enhanced in the presence of bacterial lipopolysaccharide (LPS), with as little as 10–100 pg/ml LPS potentiating the cisplatin response by 2–5‐fold and more than doubling the adriamycin response. Greater than 90% of the procoagulant activity was membrane‐bound tissue factor as indicated by the factor VII‐dependent generation of factor Xa by viable cells and by the neutralization of this activity by a monoclonal antibody to tissue factor. Tissue factor antigen was measured simultaneously by immunohistochemical staining and by cell ELISA. Blood monocytes activated with LPS expressed high levels of tissue factor antigen; by contrast, adriamycin and cisplatin did not appear to induce antigen expression, but to enhance the specific activity of that already present. Results suggest that membrane alterations which occur following treatment with DNA/RNA intercalating drugs, may result in a highly active form of monocyte/macrophage tissue factor which may contribute to the complications caused by activated coagulation. Secondary Gram‐negative infection or cyto‐kines released by an active immune response to a tumour may contribute to the procoagulant potential of these cytotoxic drugs.

Schwannomatosis, sporadic schwannomatosis, and familial schwannomatosis: a surgical series with long-term follow-up: Clinical article

OBJECT The aim of this study was to provide disease-specific information about schwannomatosis in its different forms and to present 2 particular cases of malignant schwannomas in the context of familial schwannomatosis (FS). METHODS The authors analyzed patients with pathologically defined schwannomas and identified those with varied forms of schwannomatosis. Each case was retrospectively analyzed for patient sex and age, number of operations and tumors excised, symptoms, location and size of tumors, extent of resection, nerve function pre- and postoperatively, complications, other nonsurgically treated tumors, malignancy, results of brain MR imaging, and follow-up data. RESULTS One hundred fifty-eight patients underwent the excision of 216 schwannomas. One hundred forty-two patients presented with solitary schwannomas, 2 had neurofibromatosis Type 2 (NF2), and 14 presented with schwannomatosis. The average follow-up was 52 months. Six individuals had sporadic schwannomatosis, whereas 8 had the familial form of the disease. These 14 patients had an average age of 28.3 years at the time of disease onset (median 27.5 years) and 35.4 years at the time of the first operation (median 37 years) Thirteen of the 14 patients with schwannomatosis experienced pain as the first symptom. Eight (57%) of the 14 patients presented with at least 1 tumor in the spinal canal or attached to the spinal nerve roots. Malignant schwannomas developed in 2 patients from the same family during the follow-up. CONCLUSIONS Patients suffering from schwannomatosis tend to be younger than those presenting with solitary schwannomas. Therefore, individuals presenting at a young age with multiple schwannomas but not meeting the criteria for NF2 should prompt the physician to suspect schwannomatosis. Patients with schwannomatosis who report pain should be exhaustively examined. The spine is affected in the majority of patients, and MR imaging of the spine should be part of the routine evaluation. Rapid enlargement of schwannomas in the context of FS should raise suspicion of malignant transformation.

Interim results from the CATNON trial (EORTC study 26053-22054) of treatment with concurrent and adjuvant temozolomide for 1p/19q non-co-deleted anaplastic glioma: a phase 3, randomised, open-label intergroup study

BACKGROUND The role of temozolomide chemotherapy in newly diagnosed 1p/19q non-co-deleted anaplastic gliomas, which are associated with lower sensitivity to chemotherapy and worse prognosis than 1p/19q co-deleted tumours, is unclear. We assessed the use of radiotherapy with concurrent and adjuvant temozolomide in adults with non-co-deleted anaplastic gliomas. METHODS This was a phase 3, randomised, open-label study with a 2 × 2 factorial design. Eligible patients were aged 18 years or older and had newly diagnosed non-co-deleted anaplastic glioma with WHO performance status scores of 0-2. The randomisation schedule was generated with the electronic EORTC web-based ORTA system. Patients were assigned in equal numbers (1:1:1:1), using the minimisation technique, to receive radiotherapy (59·4 Gy in 33 fractions of 1·8 Gy) alone or with adjuvant temozolomide (12 4-week cycles of 150-200 mg/m2 temozolomide given on days 1-5); or to receive radiotherapy with concurrent temozolomide 75 mg/m2 per day, with or without adjuvant temozolomide. The primary endpoint was overall survival adjusted for performance status score, age, 1p loss of heterozygosity, presence of oligodendroglial elements, and MGMT promoter methylation status, analysed by intention to treat. We did a planned interim analysis after 219 (41%) deaths had occurred to test the null hypothesis of no efficacy (threshold for rejection p<0·0084). This trial is registered with ClinicalTrials.gov, number NCT00626990. FINDINGS At the time of the interim analysis, 745 (99%) of the planned 748 patients had been enrolled. The hazard ratio for overall survival with use of adjuvant temozolomide was 0·65 (99·145% CI 0·45-0·93). Overall survival at 5 years was 55·9% (95% CI 47·2-63·8) with and 44·1% (36·3-51·6) without adjuvant temozolomide. Grade 3-4 adverse events were seen in 8-12% of 549 patients assigned temozolomide, and were mainly haematological and reversible. INTERPRETATION Adjuvant temozolomide chemotherapy was associated with a significant survival benefit in patients with newly diagnosed non-co-deleted anaplastic glioma. Further analysis of the role of concurrent temozolomide treatment and molecular factors is needed. FUNDING Schering Plough and MSD.

Intratumoral heterogeneity identified at the epigenetic, genetic and transcriptional level in glioblastoma.

Heterogeneity is a hallmark of glioblastoma with intratumoral heterogeneity contributing to variability in responses and resistance to standard treatments. Promoter methylation status of the DNA repair enzyme O6-methylguanine DNA methyltransferase (MGMT) is the most important clinical biomarker in glioblastoma, predicting for therapeutic response. However, it does not always correlate with response. This may be due to intratumoral heterogeneity, with a single biopsy unlikely to represent the entire lesion. Aberrations in other DNA repair mechanisms may also contribute. This study investigated intratumoral heterogeneity in multiple glioblastoma tumors with a particular focus on the DNA repair pathways. Transcriptional intratumoral heterogeneity was identified in 40% of cases with variability in MGMT methylation status found in 14% of cases. As well as identifying intratumoral heterogeneity at the transcriptional and epigenetic levels, targeted next generation sequencing identified between 1 and 37 unique sequence variants per specimen. In-silico tools were then able to identify deleterious variants in both the base excision repair and the mismatch repair pathways that may contribute to therapeutic response. As these pathways have roles in temozolomide response, these findings may confound patient management and highlight the importance of assessing multiple tumor biopsies.