There are no established treatments for recurrent meningioma when surgical and radiation options are exhausted. The epidermal growth factor receptor (EGFR) is often over-expressed in meningiomas and may promote tumor growth. In open label, single arm phase II studies of the EGFR inhibitors gefitinib (NABTC 00-01) and erlotinib (NABTC 01-03) for recurrent malignant gliomas, we included exploratory subsets of recurrent meningioma patients. We have pooled the data and report the results here. Patients with recurrent histologically confirmed meningiomas with no more than 2 previous chemotherapy regimens were treated with gefitinib 500 mg/day or erlotinib 150 mg/day until tumor progression or unacceptable toxicity. Twenty-five eligible patients were enrolled with median age 57 years (range 29–81) and median Karnofsky performance status (KPS) score 90 (range 60–100). Sixteen patients (64%) received gefitinib and 9 (36%) erlotinib. Eight patients (32%) had benign tumors, 9 (36%) atypical, and 8 (32%) malignant. For benign tumors, the 6-month progression-free survival (PFS6) was 25%, 12-month PFS (PFS12) 13%, 6-month overall survival (OS6) 63%, and 12-month OS (OS12) 50%. For atypical and malignant tumors, PFS6 was 29%, PFS12 18%, OS6 71%, and OS12 65%. The PFS and OS were not significantly different by histology. There were no objective imaging responses, but 8 patients (32%) maintained stable disease. Although treatment was well-tolerated, neither gefitinib nor erlotinib appear to have significant activity against recurrent meningioma. The role of EGFR inhibitors in meningiomas is unclear. Evaluation of multi-targeted inhibitors and EGFR inhibitors in combination with other targeted molecular agents may be warranted.
meningioma; erlotinib; gefitinib; epidermal growth factor receptor inhibitor
The signaling pathways that underlie the pathogenesis of pediatric gliomas are poorly understood. We characterized the PI3K/Akt/mTOR pathway in pediatric gliomas of all grades. Using immunohistochemistry, we assessed activation of the PI3K/Akt/mTOR pathway by evaluating the downstream signaling molecules phospho(p)-S6, phospho(p)-4BP1, and phospho(p)-PRAS40; PTEN; and PTEN promoter methylation, as well as the MIB labeling index. We correlated these findings with the clinical outcomes of 48 children with gliomas. Eighty percent of high-grade gliomas (12/15) showed activation of the PI3K/Akt/mTOR pathway based on p-S6 and p-4EBP1 expression. The majority of high-grade gliomas were negative for PTEN expression (10/15), and 50% had PTEN promoter methylation (grade III: 2/4; grade IV: 3/6). Low-grade gliomas demonstrated PI3K/Akt/mTOR pathway activation in 14/32 (43.8%) by p-S6 and 16/32 (50%) by p-4EBP1. Over 50% of grade I (6/11) and almost all grade II tumors (6/7) showed PTEN promoter methylation. Tumor grade correlated negatively with PTEN expression and positively with expression of p-S6 and p-4EBP1 (PTEN: P = .0025; pS6: P = .0075; p-4EBP1: P = .0066). There was a trend toward inverse correlation of methylation of the PTEN promoter with expression of PTEN protein (P= .0990) and direct correlation of expression of p-S6 and p-4EBP1 with poorer clinical outcome, as measured by progression-free survival (p-S6: P= .0874; p-4EBP1: P= .0475). Tumors with no PTEN expression had a higher MIB labeling index (P= .007). The majority of pediatric gliomas show activation of the PI3K/Akt/mTOR pathway, with methylation of the PTEN promoter occurring commonly in these tumors.
pediatric gliomas; PI3K/Akt/mTOR; PTEN promoter methylation
Glioblastoma is a devastating, incurable disease with few known prognostic factors. Here we present the first genome-wide survival and validation study for glioblastoma.
Cox regressions for survival with 314,635 inherited autosomal single nucleotide polymorphisms (SNPs) among 315 San Francisco Adult Glioma Study patients for discovery and three independent validation datasets (87 Mayo Clinic, 232 GliomaSE and 115 The Cancer Genome Atlas patients) were used to identify SNPs associated with overall survival for Caucasian glioblastoma patients treated with the current standard of care, resection, radiation and temozolomide (total n=749). Tumor expression of the gene that contained the identified prognostic SNP was examined in three separate datasets (total n=619). Genotype imputation was used to estimate hazard ratios (HRs) for SNPs that had not been directly genotyped.
From the discovery and validation analyses, we identified a variant in SSBP2 (single-stranded DNA-binding protein 2) on 5q14.1 associated with overall survival in combined analyses (hazard ratio (HR) = 1.64; P = 1.3X10−6). Expression of SSBP2 in tumors from three independent datasets also was significantly related to patient survival (P = 5.3 X 10−4). Using genotype imputation, the SSBP2 SNP rs17296479 had the strongest statistically significant genome-wide association with poorer overall patient survival (HR = 1.79; 95% CI: 1.45–2.22; P = 1.0 X 10−7).
The minor allele of SSBP2 SNP rs17296479 and the increased tumor expression of SSBP2 were statistically significantly associated with poorer overall survival among glioblastoma patients. With further confirmation, previously unrecognized inherited variations influencing survival may warrant inclusion in clinical trials to improve randomization. Unaccounted for genetic influence on survival could produce unwanted bias in such studies.
glioma; glioblastoma; GWAS; survival; epidemiology; SSBP2
A recent study of CDK4/6-inhibitors in glioblastoma (GBM) xenografts identified retinoblastoma tumor suppressor protein RB1 status as a determinant of tumor therapeutic efficacy. Because of the need for clinically applicable RB1 testing, we assessed the utility of 2 complementary methods for determining RB1 status in GBM. Using fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC), we analyzed 34 GBMs that had also undergone molecular characterization as part of The Cancer Genome Atlas (TCGA). By IHC, 4 tumors (11.8%) had complete loss of RB protein expression, including 2 with homozygous deletion of RB1 by FISH and 1 with hemizygous deletion of RB1 by FISH combined with a novel nonsense mutation in RB1. Consistent with these results, in an independent set of 51 GBMs tested by IHC we demonstrated loss of RB1 protein in 5 (9.8%). In GBM molecular subtype analysis of TCGA data, complete loss of RB1 transcript expression was seen in 18 of 170 tumors (10.6%) and these were highly enriched for, but not exclusive to, the proneural subtype (p < 0.01). These data support the use of IHC for determining RB1 status in clinical GBM specimens and suggest that RB1 alterations may be more common in certain GBM subgroups.
Fluorescence in situ hybridization; Glioblastoma; Immunohistochemistry; Patient stratification; RB1; The Cancer Genome Atlas (TCGA)
This open-label, single-arm, phase II study combined enzastaurin with temozolomide plus radiation therapy (RT) to treat glioblastoma multiforme (GBM) and gliosarcoma. Adults with newly diagnosed disease and Karnofsky performance status (KPS) ≥ 60 were enrolled. Treatment was started within 5 weeks after surgical diagnosis. RT consisted of 60 Gy over 6 weeks. Temozolomide was given at 75 mg/m2 daily during RT and then adjuvantly at 200 mg/m2 daily for 5 days, followed by a 23-day break. Enzastaurin was given once daily during RT and in the adjuvant period at 250 mg/day. Cycles were 28 days. The primary end point was overall survival (OS). Progression-free survival (PFS), toxicity, and correlations between efficacy and molecular markers analyzed from tumor tissue samples were also evaluated. A prospectively planned analysis compared OS and PFS of the current trial with outcomes from 3 historical phase II trials that combined novel agents with temozolomide plus RT in patients with GBM or gliosarcoma. Sixty-six patients were enrolled. The treatment regimen was well tolerated. OS (median, 74 weeks) and PFS (median, 36 weeks) results from the current trial were comparable to those from a prior phase II study using erlotininb and were significantly better than those from 2 other previous studies that used thalidomide or cis-retinoic acid, all in combination with temozolomide plus RT. A positive correlation between O-6-methylguanine-DNA methyltransferase promoter methylation and OS was observed. Adjusting for age and KPS, no other biomarker was associated with survival outcome. Correlation of relevant biomarkers with OS may be useful in future trials.
adjuvant therapy; enzastaurin; glioblastoma multiforme; radiation therapy; temozolomide
Achieving effective treatment outcomes for patients with glioblastoma (GBM) has been impeded by many obstacles, including the pharmacokinetic limitations of antitumor agents, such as topotecan (TPT). Here, we demonstrate that intravenous administration of a novel nanoliposomal formulation of TPT (nLS-TPT) extends the survival of mice with intracranial GBM xenografts, relative to administration of free TPT, because of improved biodistribution and pharmacokinetics of the liposome-formulated drug. In 3 distinct orthotopic GBM models, 3 weeks of biweekly intravenous therapy with nLS-TPT was sufficient to delay tumor growth and significantly extend animal survival, compared with treatment with free TPT (P ≤ .03 for each tumor tested). Analysis of intracranial tumors showed increased activation of cleaved caspase-3 and increased DNA fragmentation, both indicators of apoptotic response to treatment with nLS-TPT. These results demonstrate that intravenous delivery of nLS-TPT is a promising strategy in the treatment of GBM and support clinical investigation of this therapeutic approach.
bioluminescence imaging; glioma; liposome; topotecan; xenograft
Historically, the North American Brain Tumor Consortium used 6-month progression-free survival (PFS6) as the primary outcome for recurrent glioma phase II clinical trials. In some trials, a subset of patients received the trial treatment before surgery to assess tumor uptake and biological activity. We compared PFS6 and overall survival (OS) for patients with glioblastoma undergoing surgery at progression to results for those without surgery to evaluate the impact of surgical intervention on these outcomes. Two data sets were analyzed. The first included 511 patients enrolled during the period 1998–2005, 105 of whom had surgery (excluding biopsies) during the study or ≤30 days prior to registration. Analysis was stratified on the basis of whether temozolomide was part of the protocol treatment regimen. The second data set included 247 patients enrolled during 2005–2008, 103 of whom underwent surgery during the clinical trial or immediately prior to study registration. A combined data set consisting of all patients who did not receive temozolomide was also compiled. No statistically significant difference in PFS6 or OS was found between the surgery and nonsurgery groups in either data set alone or in the combined data set (P > .45). We conclude that PFS6 and OS results for patients with and without surgical intervention at the time of progression are similar, allowing data from these patients to be combined in assessing the benefit of new treatments without the need for stratification or other statistical adjustment.
glioblastoma; PFS6; prognosis; recurrence; surgery
Antivascular endothelial growth factor (anti-VEGF) therapy is a promising treatment approach for patients with recurrent glioblastoma. This single-arm phase II study evaluated the efficacy of aflibercept (VEGF Trap), a recombinantly produced fusion protein that scavenges both VEGF and placental growth factor in patients with recurrent malignant glioma.
Patients and Methods
Forty-two patients with glioblastoma and 16 patients with anaplastic glioma who had received concurrent radiation and temozolomide and adjuvant temozolomide were enrolled at first relapse. Aflibercept 4 mg/kg was administered intravenously on day 1 of every 2-week cycle.
The 6-month progression-free survival rate was 7.7% for the glioblastoma cohort and 25% for patients with anaplastic glioma. Overall radiographic response rate was 24% (18% for glioblastoma and 44% for anaplastic glioma). The median progression-free survival was 24 weeks for patients with anaplastic glioma (95% CI, 5 to 31 weeks) and 12 weeks for patients with glioblastoma (95% CI, 8 to 16 weeks). A total of 14 patients (25%) were removed from the study for toxicity, on average less than 2 months from treatment initiation. The main treatment-related National Cancer Institute Common Terminology Criteria grades 3 and 4 adverse events (38 total) included fatigue, hypertension, and lymphopenia. Two grade 4 CNS ischemias and one grade 4 systemic hemorrhage were reported. Aflibercept rapidly decreases permeability on dynamic contrast enhanced magnetic resonance imaging, and molecular analysis of baseline tumor tissue identified tumor-associated markers of response and resistance.
Aflibercept monotherapy has moderate toxicity and minimal evidence of single-agent activity in unselected patients with recurrent malignant glioma.
Romidepsin, a potent histone deacetylase inhibitor, has shown activity in preclinical glioma models. The primary objectives of this trial were to determine the pharmacokinetics of romidepsin in patients with recurrent glioma on enzyme-inducing antiepileptic drugs (EIAEDs) and to evaluate the antitumor efficacy of romidepsin in patients with recurrent glioblastoma who were not receiving EIAEDs. Two dose cohorts were studied in the phase I component of the trial (13.3 and 17.7 mg/m2/d). Patients in the phase II component were treated with intravenous romidepsin at a dosage of 13.3 mg/m2/day on days 1, 8, and 15 of each 28-day cycle. Eight patients were treated on the phase I component. A similar romidepsin pharmacokinetic profile was demonstrated between patients receiving EIAEDs to those not receving EIAEDs. Thirty-five patients with glioblastoma were accrued to the phase II component. There was no objective radiographic response. The median progression-free survival (PFS) was 8 weeks and only 1 patient had a PFS time ≥6 months (PFS6 = 3%). To date, 34 patients (97%) have died, with a median survival duration of 34 weeks. Despite in vitro studies showing that romidepsin is primarily metabolized by CYP3A4, no decrease in exposure to romidepsin was seen in patients receiving potent CYP3A4 inducers. Romidepsin, at its standard dose and schedule, was ineffective for patients with recurrent glioblastomas.
ClinicalTrials.gov identifier: NCT00085540.
glioblastoma; glioma; histone deacetylase inhibitor; romidepsin
To address the association between sequence variants within the MGMT promoter-enhancer region and methylation of MGMT in premalignant lesions from smokers and lung adenocarcinomas, their biological effects on gene regulation, and targeting MGMT for therapy.
SNPs identified through sequencing a 1.9kb fragment 5' of MGMT were examined in relation to MGMT methylation in 169 lung adenocarcinomas and 1731 sputum samples from smokers. The effect of promoter haplotypes on MGMT expression was tested using a luciferase reporter assay and cDNA expression analysis along with allele-specific sequencing for methylation. The response of MGMT methylated lung cancer cell lines to the alkylating agent temozolomide was assessed.
The A allele of rs16906252 and the haplotype containing this SNP were strongly associated with increased risk for MGMT methylation in adenocarcinomas (ORs ≥ 94). This association was observed to a lesser extent in sputum samples in both smoker cohorts. The A allele was selectively methylated in primary lung tumors and cell lines heterozygous for rs16906252. With the most common haplotype as the reference, a 20–41% reduction in promoter activity was seen for the haplotype carrying the A allele that correlated with lower MGMT expression. The sensitivity of lung cancer cell lines to temozolamide was strongly correlated with levels of MGMT methylation and expression.
These studies provide strong evidence that the A allele of a MGMT promoter-enhancer SNP is a key determinant for MGMT methylation in lung carcinogenesis. Moreover, temozolamide treatment may benefit a subset of lung cancer patients methylated for MGMT.
MGMT; allele specific methylation; single nucleotide polymorphism; sputum; lung cancer
Due to its molecular heterogeneity and infiltrative nature, glioblastoma multiforme (GBM) is notoriously resistant to traditional and experimental therapeutics. To overcome these hurdles, targeted agents have been combined with conventional therapy. We evaluated the preclinical potential of a novel, orally bioavailable PI3K/mTOR dual inhibitor (XL765) in in vitro and in vivo studies. In vivo serially passaged human GBM xenografts that are more genetically stable than GBM cell lines in culture were used for all experiments. Biochemical downstream changes were evaluated by immunoblot and cytotoxicity by colorimetric ATP-based assay. For in vivo experiments, human xenograft GBM 39 grown intracranially in nude mice was altered to express luciferase to monitor tumor burden by optical imaging. XL765 resulted in concentration-dependent decreases in cell viability in vitro. Cytotoxic doses resulted in specific inhibition of PI3K signaling. Combining XL765 with temozolomide (TMZ) resulted in additive toxicity in 4 of 5 xenografts. In vivo, XL765 administered by oral gavage resulted in greater than 12-fold reduction in median tumor bioluminescence compared with control (Mann–Whitney test p = 0.001) and improvement in median survival (logrank p = 0.05). TMZ alone showed a 30-fold decrease in median bioluminescence, but the combination XL765 + TMZ yielded a 140-fold reduction in median bioluminescence (Mann-Whitney test p = 0.05) with a trend toward improvement in median survival (logrank p = 0.09) compared with TMZ alone. XL765 shows activity as monotherapy and in combination with conventional therapeutics in a range of genetically diverse GBM xenografts.
PI3K/mTOR inhibitor; glioma; temozolomide; signaling inhibitor
We performed a phase II study to assess the efficacy and toxicity of tipifarnib, a farnesyltransferase inhibitor, administered with radiation therapy (RT) in children with newly diagnosed diffuse intrinsic pontine gliomas. Children 3-21 years old with pontine gliomas (BSGs) were treated with concurrent tipifarnib and RT, followed by adjuvant tipifarnib. Tipifarnib was taken orally twice daily (125 mg/m2/dose) during RT; after RT, it was taken at 200 mg/m2 twice daily for 21 days, in 28-day cycles. Initial and follow-up neuroimaging was centrally reviewed. Forty eligible patients (median age, 5.5 years; range, 3.3–16.5 years) had a median progression-free survival of 6.8 months (range, 0.2-18.6 months) and median overall survival of 8.3 months (range, 0.2-18.6 months). Kaplan–Meier estimates (± standard error) of 1-year progression-free and overall survival were 12.9% ±4.9% and 34.3% ±7.4%, respectively. A single patient remained on tipifarnib without progression at the completion of the study, two years after initiation of treatment. Seven patients were without disease progression for at least six months, three of whom remained controlled for more than a year. The most frequent toxicity was grade 3 lymphopenia. We documented a single instance of “pseudoprogression” by neuroimaging review. We found no discordance among 3 approaches to defining disease progression: as interpreted by treating institutions (based on clinical status and/or imaging) and by central review (using bi-dimensional tumor “area” versus volumetric measurements). For children with diffuse BSGs, tipifarnib administered with irradiation offered no clinical advantage over historical controls. Biopsies and molecular analyses of pediatric BSGs are vital for identification of new agents and for rational use of targeted agents.
diffuse intrinsic pontine glioma; farnesyltransferase inhibitors; pediatric
We explored the associations of aberrant DNA methylation patterns in 12 candidate genes with adult glioma subtype, patient survival, and gene expression of enhancer of zeste human homolog 2 (EZH2) and insulin-like growth factor-binding protein 2 (IGFBP2). We analyzed 154 primary glioma tumors (37 astrocytoma II and III, 52 primary glioblastoma multiforme (GBM), 11 secondary GBM, 54 oligodendroglioma/oligoastrocytoma II and III) and 13 nonmalignant brain tissues for aberrant methylation with quantitative methylation-specific PCR (qMS-PCR) and for EZH2 and IGFBP2 expression with quantitative reverse transcription PCR (qRT-PCR). Global methylation was assessed by measuring long interspersed nuclear element-1 (LINE1) methylation. Unsupervised clustering analyses yielded 3 methylation patterns (classes). Class 1 (MGMT, PTEN, RASSF1A, TMS1, ZNF342, EMP3, SOCS1, RFX1) was highly methylated in 82% (75/91) of lower-grade astrocytic and oligodendroglial tumors, 73% (8/11) of secondary GBMs, and 12% (6/52) of primary GBMs. The primary GBMs in this class were early onset (median age 37 years). Class 2 (HOXA9 and SLIT2) was highly methylated in 37% (19/52) of primary GBMs. None of the 10 genes for class 3 that were differentially methylated in classes 1 and 2 were hypermethylated in 92% (12/13) of nonmalignant brain tissues and 52% (27/52) of primary GBMs. Class 1 tumors had elevated EZH2 expression but not elevated IGFBP2; class 2 tumors had both high IGFBP2 and high EZH2 expressions. The gene-specific hypermethylation class correlated with higher levels of global LINE1 methylation and longer patient survival times. These findings indicate a generalized hypermethylation phenotype in glioma linked to improved survival and low IGFBP2. DNA methylation markers are useful in characterizing distinct glioma subtypes and may hold promise for clinical applications.
glioma; DNA methylation; EZH2; Polycomb; PI3K/Akt
Erlotinib, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, is active in glioblastoma. We evaluated erlotinib efficacy in patients with first-relapse glioblastoma and assessed whether response was related to EGFR amplification and/or concomitant use of enzyme-inducing antiepileptic drugs (EIAEDs) in a phase II open-label study of glioblastoma patients in first relapse. Patients took erlotinib daily until progression. Starting dose was 150 mg for patients not taking EIAEDs and 300 mg for patients taking EIAEDs. Tumors were radiographically assessed every 8 weeks. Response was evaluated by investigators and confirmed by an independent radiology facility (IRF). The primary efficacy outcome was the objective response (OR) rate, according to the modified WHO criteria. Enrollment (n = 48) was terminated after a planned interim analysis due to an insufficient number of responses. The IRF confirmed 1 complete and 2 partial responses (PRs), for an OR rate of 6.3% (95% confidence interval [CI]: 1.7–17.0). Investigators determined 1 complete response and 3 PRs, median response duration of 7.0 months, 6-month progression-free survival (PFS) of 20% (95% CI: 10.0–32.4), and median survival of 9.7 months (95% CI: 5.9–11.6). Outcomes were not related to EGFR amplification or EIAED status. Diarrhea and rash were the most common adverse events (AEs); 23% of patients experienced grade 3–4 drug-related AEs. Despite the limited number of responses, 6-month PFS and median survival reached or exceeded the previously reported values for patients undergoing chemotherapy for recurrent glioblastoma. EGFR amplification was not associated with erlotinib activity. Given the large CIs and nonrandomized nature of the study, results should be interpreted cautiously.
EGFR amplification; EGFR inhibition; enzyme-inducing antiepileptic drugs; progression-free survival
We report a case of multifocal demyelination within the central nervous system in a patient being treated for a left hemispheric gemnistocytic astrocytoma with radiation therapy and chemotherapy, comprising temozolomide (360 mg/day—days 1–5 every 28 days) and 13-cis-retinoic acid (100 mg/m2/day—separated into two doses administered every 12 h on days 1 through 21 every 28 days). Five months into her first round of chemotherapy, brain magnetic resonance imaging (MRI) demonstrated multifocal regions of T2 prolongation with associated gadolinium enhancement within the right cerebral hemisphere. Spectroscopic data were consistent with demyelination rather than neoplasia. Despite the incidentally identified radiological progression, new neurological symptoms were not described. Interval resolution of the demyelinating lesions was observed in the years following the discontinuance of her chemotherapy regimen with reactivation of the previously observed lesions and the development of new T2 foci 6 months into her second round of re-treatment for tumour progression 5 years later.
The objective of this phase II single-arm study was to evaluate the efficacy and safety of pazopanib, a multi-targeted tyrosine kinase inhibitor, against vascular endothelial growth factor receptor (VEGFR)-1, -2, and -3, platelet-derived growth factor receptor-α and -β, and c-Kit, in recurrent glioblastoma. Patients with ≤2 relapses and no prior anti-VEGF/VEGFR therapy were treated with pazopanib 800 mg daily on 4-week cycles without planned interruptions. Brain magnetic resonance imaging and clinical reassessment were made every 8 weeks. The primary endpoint was efficacy as measured by 6-month progression-free survival (PFS6). Thirty-five GBM patients with a median age of 53 years and median Karnofsky performance scale of 90 were accrued. Grade 3/4 toxicities included leukopenia (n = 1), lymphopenia (n = 2), thrombocytopenia (n = 1), ALT elevation (n = 3), AST elevation (n = 1), CNS hemorrhage (n = 1), fatigue (n = 1), and thrombotic/embolic events (n = 3); 8 patients required dose reduction. Two patients had a partial radiographic response by standard bidimensional measurements, whereas 9 patients (6 at the 8-week point and 3 only within the first month of treatment) had decreased contrast enhancement, vasogenic edema, and mass effect but <50% reduction in tumor. The median PFS was 12 weeks (95% confidence interval [CI]: 8–14 weeks) and only 1 patient had a PFS time ≥6 months (PFS6 = 3%). Thirty patients (86%) had died and median survival was 35 weeks (95% CI: 24–47 weeks). Pazopanib was reasonably well tolerated with a spectrum of toxicities similar to other anti-VEGF/VEGFR agents. Single-agent pazopanib did not prolong PFS in this patient population but showed in situ biological activity as demonstrated by radiographic responses. ClinicalTrials.gov identifier: NCT00459381.
antiangiogenesis; clinical therapy trials; giloblastoma
We conducted a phase I study to determine the safety and recommended phase II dose of enzastaurin (oral inhibitor of the protein kinase C-beta [PKCβ] and the PI3K/AKT pathways) when given in combination with radiation therapy (RT) plus temozolomide to patients with newly diagnosed glioblastoma multiforme or gliosarcoma. Patients with Karnofsky performance status ≥60 and no enzyme-inducing anti-epileptic drugs received RT (60 Gy) over 6 weeks, concurrently with temozolomide (75 mg/m2 daily) followed by adjuvant temozolomide (200 mg/m2) for 5 days/28-d cycle. Enzastaurin was given once daily during RT and adjuvantly with temozolomide; the starting dose of 250 mg/d was escalated to 500 mg/d if ≤1/6 patients had dose-limiting toxicity (DLT) during RT and the first adjuvant cycle. Patients continued treatment for 12 adjuvant cycles unless disease progression or unacceptable toxicity occurred. Twelve patients enrolled. There was no DLT in the first 6 patients treated with 250 mg enzastaurin. At 500 mg, 2 of 6 patients experienced a DLT (1 Grade 4 and 1 Grade 3 thrombocytopenia). The patient with Grade 3 DLT recovered to Grade <1 within 28 days and adjuvant temozolomide and enzastaurin was reinitiated with dose reductions. The other patient recovered to Grade <1 toxicity after 28 days and did not restart treatment. Enzastaurin 250 mg/d given concomitantly with RT and temozolomide and adjuvantly with temozolomide was well tolerated and is the recommended phase II dose. The proceeding phase II trial has finished accrual and results will be reported in 2009.
adjuvant therapy; enzastaurin; glioblastoma multiforme; radiation therapy; temozolomide
This phase II study was designed to determine the objective response rate and 6-month progression free survival of adult patients with recurrent supratentorial anaplastic glioma when treated with the immune modulator, polyinosinic-polycytidylic acid stabilized with polylysine and carboxymethylcellulose (poly-ICLC).
Methods and Materials
This was an open-labeled, single arm phase II study. Patients were treated with poly-ICLC alone. Patients may have had treatment for no more than two prior relapses. Treatment with poly-ICLC continued until tumor progression.
55 patients were enrolled in the study. 10 were ineligible after central review of pathology. 11% of patients (5 of 45) had a radiographic response. Time to progression was known for 39 patients and 6 remain on treatment. The estimated 6-month progression free survival was 24%. The median survival time was 43 weeks.
Poly-ICLC was well tolerated, but there was no improvement in 6-month progression free survival compared to historical database nor was there an encouraging objective radiographic response rate. Based on this study, poly-ICLC does not improve 6moPFS in patients with recurrent anaplastic gliomas but may be worth further study in combination with agents such as temozolomide.
anaplastic glioma; radiation therapy; adjuvant therapy; poly-ICLC
Activation of cyclin-dependent kinases 4 and 6 (cdk4/6) occurs in the majority of glioblastoma multiforme (GBM) tumors, and represents a promising molecular target for the development of small molecule inhibitors. In the current study we investigated the molecular determinants and in vivo response of diverse GBM cell lines and xenografts to PD-0332991, a cdk4/6 specific inhibitor. In vitro testing of PD-0332991 against a panel of GBM cell lines revealed a potent G1 cell cycle arrest and induction of senescence in each of 16 Rb-proficient cell lines regardless of other genetic lesions, whereas each of 5 cell lines with homozygous inactivation of Rb were completely resistant to treatment. shRNA depletion of Rb expression conferred resistance of GBM cells to PD-0332991, further demonstrating a requirement of Rb for sensitivity to cdk4/6 inhibition. PD-0332991 was found to efficiently cross the blood-brain barrier and proved highly effective in suppressing the growth of intracranial GBM xenograft tumors, including those that had recurred after initial therapy with temozolomide. Remarkably, no mice receiving PD-0332991 had significant disease progression or died while on therapy. Additionally, the combination of PD-0332991 and radiation therapy resulted in significantly increased survival benefit compared with either therapy alone. In total, our results support clinical trial evaluation of PD-0332991 against newly-diagnosed as well as recurrent GBM, and indicate that Rb status is the primary determinant of potential benefit from this therapy.
glioblastoma; cyclin-dependent kinase; Rb; p16INK4a; PD-0332991; bioluminescence
Atypical teratoid rhabdoid tumor (ATRT) is a malignant tumor of the central nervous system that most commonly arises in young children. The aggressive growth and propensity for early dissemination throughout the neuraxis confers a dismal prognosis. Large clinical trials that could test new therapeutic agents are difficult to conduct due to the low incidence of this cancer. For this reason, high throughput preclinical testing with suitable animal models for ATRT would serve a critical need for identifying the most efficacious treatments. In response to this need, we have adapted ATRT cell lines for bioluminescence imaging (BLI) of intracranial (orthotopic) xenografts established in athymic mice. Our results indicate that following supratentorial or infratentorial injection in athymic mice, ATRT cells produce rapidly growing tumors, often with intraventricular spread or neuraxis dissemination. When established as orthotopic xenografts, the tumors predominantly display cells with a rhabdoid-like cellular morphology that show a spectrum of immunophenotypes similar to primary ATRT tumors. To demonstrate the feasibility of this orthotopic ATRT xenograft model for therapeutic testing with correlation to biomarker analysis, we examined the responses of luciferase-modified ATRT cells to temozolomide (TMZ). These xenografts, which highly express MGMT, are resistant to TMZ treatment when compared with an orthotopic glioblastoma xenograft that is MGMT deficient and responsive to TMZ. These data suggest that an orthotopic ATRT xenograft model, in which BLI is used for monitoring tumor growth and response to therapy, should contribute to the identification of effective therapeutics and regimens for treating this highly aggressive pediatric brain tumor.
atypical teratoid rhabdoid tumor; xenograft; orthotopic; INI1; bioluminescence
The purpose of this study is to determine prognostic factors in patients with high-grade recurrent glioma for 3 outcome variables (overall survival, progression-free survival [PFS], and PFS rate 6 months after study registration [PFS6]). Data from 15 North Central Cancer Treatment Group (NCCTG) trials (n = 469, 1980–2004) and 12 North American Brain Tumor Consortium (NABTC) trials (n = 596, 1998–2002) were included. Eighteen prognostic variables were considered including type of treatment center (community/academic) and initial low-grade histology (yes/no). Recursive partitioning analysis (RPA), Cox proportional hazards, and logistic regression models with bootstrap resampling were used to identify prognostic variables. Longer survival was associated with last known grade (Grade) of III, younger age, ECOG performance score (PS) of 0, shorter time from initial diagnosis (DxTime), and no baseline steroid use. Factors associated with longer PFS were Grade III and shorter DxTime. For patients without temozolomide as part of the treatment regimen, the only factor associated with better PFS6 was Grade III, although DxTime was important in RPA and PS was important in logistic regression. Grade was the most important prognostic factor for all three endpoints regardless of the statistical method used. Other important variables for one or more endpoints included age, PS, and DxTime. Neither type of treatment center nor initial low-grade histology was identified as a major predictor for any endpoint.
brain tumors; high grade; prognostic factors; recurrent glioma
Patients with (a) recurrent malignant glioma (MG): glioblastoma (GBM) or recurrent anaplastic glioma (AG), and (b) nonprogressive (NP) GBM following radiation therapy (RT) were eligible. Primary objective for recurrent MG was progression-free survival at 6 months (PFS-6) and overall survival at 12 months for NP GBM post-RT. Secondary objectives for recurrent MGs were response, survival, assessment of toxicity, and pharmacokinetics (PKs). Treatment with enzyme-inducing antiepileptic drugs was not allowed. Patients received 150 mg/day erlotinib. Patients requiring surgery were treated 7 days prior to tumor removal for PK analysis and effects of erlotinib on epidermal growth factor receptor (EGFR) and intracellular signaling pathways. Ninety-six patients were evaluable (53 recurrent MG and 43 NP GBM); 5 patients were not evaluable for response. PFS-6 in recurrent GBM was 3% with a median PFS of 2 months; PFS-6 in recurrent AG was 27% with a median PFS of 2 months. Twelve-month survival was 57% in NP GBMs post-RT. Primary toxicity was dermatologic. The tissue-to-plasma ratio normalized to nanograms per gram dry weight for erlotinib and OSI-420 ranged from 25% to 44% and 30% to 59%, respectively, for pretreated surgical patients. No effect on EGFR or intratumoral signaling was seen. Patients with NP GBM post-RT who developed rash in cycle 1 had improved survival (P < .001). Single-agent activity of erlotinib is minimal for recurrent MGs and marginally beneficial following RT for NP GBM patients. Development of rash in cycle 1 correlates with survival in patients with NP GBM after RT.
erlotinib; glioblastoma; glioma; meningioma; pharmacokinetics
The objective of this phase I study was to determine the maximal tolerated dose (MTD) of erlotinib in patients with recurrent malignant gliomas (MGs) or recurrent meningiomas on enzyme-inducing antiepileptic drugs (EIAEDs). Dose escalation was by a standard 3 × 3 design. The initial starting dose of erlotinib was 150 mg daily. If no dose-limiting toxicity (DLT) was observed, then dose escalation occurs as follows: 200 mg/day, 275 mg/day, and then increased in 125 mg increments until the MTD was reached. The MTD was defined as the dose where ≤1 of 6 patients experienced a DLT and the dose above had 2 or more DLTs. The MTD was 650 mg/day; the observed DLTs were grade 3 rash in 2 patients at 775 mg/day. Pharmacokinetic analysis showed a significant influence of EIAEDs on the metabolism of erlotinib when compared with our phase II data published separately. Primary toxicities were rash and diarrhea. The MTD of erlotinib in patients receiving EIAEDs is substantially higher than the standard dose of 150 mg. This has important implications for further development of this drug in the treatment of MG as well as the optimal management of patients with other malignancies such as NSCLC who are on enzyme-inducing drugs.
erlotinib; glioblastoma; glioma; meningioma; pharmacokinetics