Citations

Purpose Vorinostat, a histone deacetylase inhibitor, represents a rational therapeutic target in glioblastoma multiforme (GBM). Patients and Methods Patients with recurrent GBM who had received one or fewer chemotherapy regimens for progressive disease were eligible. Vorinostat was administered at a dose of 200 mg orally twice a day for 14 days, followed by a 7-day rest period. Results A total of 66 patients were treated. Grade 3 or worse nonhematologic toxicity occurred in 26% of patients and consisted mainly of fatigue (17%), dehydration (6%), and hypernatremia (5%); grade 3 or worse hematologic toxicity occurred in 26% of patients and consisted mainly of thrombocytopenia (22%). Pharmacokinetic analysis showed lower vorinostat maximum concentration and area under the curve (0 to 24 hours) values in patients treated with enzyme-inducing anticonvulsants, although this did not reach statistical significance. The trial met the prospectively defined primary efficacy end point, with nine of the first 52 patients being progression-free at 6 months. Median overall survival from study entry was 5.7 months (range, 0.7 to 28+ months). Immunohistochemical analysis performed in paired baseline and post-vorinostat treatment samples in a separate surgical subgroup of five patients with recurrent GBM showed post treatment increase in acetylation of histones H2B and H4 (four of five patients) and of histone H3 (three of five patients). Microarray RNA analysis in the same samples showed changes in genes regulated by vorinostat, such as upregulation of E-cadherin (P = .02). Conclusion Vorinostat monotherapy is well tolerated in patients with recurrent GBM and has modest single-agent activity. Histone acetylation analysis and RNA expression profiling indicate that vorinostat in this dose and schedule affects target pathways in GBM. Additional testing of vorinostat in combination regimens is warranted.

Abstract Purpose: Hyperactivation of the phosphatidylinositol 3-kinase/Akt signaling through disruption of PTEN function is common in glioblastoma multiforme, and these genetic changes are predicted to enhance sensitivity to mammalian target of rapamycin (mTOR) inhibitors such as RAD001 (everolimus). Experimental Design: To test whether PTEN loss could be used as a predictive marker for mTOR inhibitor sensitivity, the response of 17 serially transplantable glioblastoma multiforme xenografts was evaluated in an orthotopic therapy evaluation model. Of these 17 xenograft lines, 7 have either genomic deletion or mutation of PTEN. Results: Consistent with activation of Akt signaling, there was a good correlation between loss of PTEN function and elevated levels of Akt phosphorylation. However, of the 7 lines with disrupted PTEN function, only 1 tumor line (GBM10) was significantly sensitive to RAD001 therapy (25% prolongation in median survival), whereas 1 of 10 xenograft lines with wild-type PTEN was significantly sensitive to RAD001 (GS22; 34% prolongation in survival). Relative to placebo, 5 days of RAD001 treatment was associated with a marked 66% reduction in the MIB1 proliferation index in the sensitive GBM10 line (deleted PTEN) compared with a 25% and 7% reduction in MIB1 labeling index in the insensitive GBM14 (mutant PTEN) and GBM15 (wild-type PTEN) lines, respectively. Consistent with a cytostatic antitumor effect, bioluminescent imaging of luciferase-transduced intracranial GBM10 xenografts showed slowed tumor growth without significant tumor regression during RAD001 therapy. Conclusion: These data suggest that loss of PTEN function is insufficient to adequately predict responsiveness to mTOR inhibitors in glioblastoma multiforme.

Abstract Purpose: Glioblastoma multiforme is the most frequent primary brain tumor in adults and represents one of the most lethal malignancies with a median survival of 12-16 months. We have previously shown that an oncolytic measles virus derivative expressing soluble human carcinoembryonic antigen (MV-CEA) has significant antitumor activity against glioblastoma multiforme cell lines and xenografts. Radiation therapy (RT) represents one of the mainstays of glioma treatment. Here we tested the hypothesis that the combination of RT with MV-CEA would have synergistic activity against gliomas. Experimental Design: 3-(4,5-Dimethyl-thiazol-2yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) and clonogenic assays were used to test cytoxicity of the combination treatment in vivo. To examine the mechanism of synergy, one-step viral growth curves, terminal deoxyribonucleotidyl transferase–mediated dUTP nick end labeling (TUNEL) assays, and Western blot analyses were performed. In vivo assessment of synergistic antitumor activity was conducted in a U87 glioma model. Results: MTS and clonogenic assays showed a strong synergistic interaction between MV-CEA and RT in glioblastoma multiforme cells including both primary and established glioma lines. Furthermore, significant antitumor efficacy was observed in vivo in a subcuteneous U87 xenograph model. There was significant prolongation of survival (P = 0.001) in the combination treatment group as compared with single modality– or control-treated animals. One-step viral growth curves showed increased viral burst size by up to 2 log in MV/RT combination–treated cells, as compared with single agent MV-CEA–treated glioma cells. Changes in CEA levels and expression of viral N and H protein were also consistent with increased viral production. Furthermore, TUNEL assays and Western blot analysis showed increase in apoptosis in MV/RT combination–treated cells. The pan-caspase inhibitor Z-VAD-FMK and the caspase-8 inhibitor Z-IETD-FMK, but not the caspase-9 inhibitor Z-IEHD-FMK, protected glioma cells from MV-CEA/RT–induced cleavage of poly(ADP-ribose) polymerase (PARP), indicating that the apoptotic death in combination-treated cells is mostly mediated via the extrinsic caspase pathway. The Fas/Fas ligand interaction blocking antibody NOK-1 blocked MV/RT–induced PARP cleavage whereas the Fas agonistic antibody CH11 increased PARP cleavage in MV/RT combination–treated cells. Reverse transcription-PCR, fluorescence-activated cell sorting analysis and immunohistochemistry showed up-regulation of Fas in combination-treated tumor in vitro and in vivo cells. Conclusions: There is synergy between MV-CEA and RT in vitro and in vivo. The synergistic effect of the combination seems to be due to increase in viral burst size and increase in apoptotic cell death. This latter effect is mostly mediated via the extrinsic caspase-8 pathway, activated via increased signaling through the Fas death receptor pathway. These results could have translational implications in glioma therapy.

Abstract In the current study, we examined a panel of serially passaged glioblastoma xenografts, in the context of an intracranial tumor therapy response model, to identify associations between glioblastoma molecular characteristics and tumor sensitivity to the epidermal growth factor receptor (EGFR) kinase inhibitor erlotinib. From an initial evaluation of 11 distinct glioblastoma xenografts, two erlotinib-sensitive tumors were identified, each having amplified EGFR and expressing wild-type PTEN. One of these tumors expressed truncated EGFRvIII, whereas the other expressed full-length EGFR. Subsequent cDNA sequence analysis revealed the latter tumor as expressing an EGFR sequence variant with arginine, rather than leucine, at amino acid position 62; this was the only EGFR sequence variant identified among the 11 xenografts, other than the aforementioned vIII sequence variant. EGFR cDNAs were then examined from 12 more xenografts to determine whether additional missense sequence alterations were evident, and this analysis revealed one such case, expressing threonine, rather than alanine, at amino acid position 289 of the extracellular domain. This glioblastoma was also amplified for EGFR, but did not display significant erlotinib sensitivity, presumably due to its lacking PTEN expression. In total, our study identified two erlotinib-sensitive glioblastoma xenografts, with the common molecular characteristics shared by each being the expression of wild-type PTEN in combination with the expression of amplified and aberrant EGFR. [Mol Cancer Ther 2007;6(3):1167–74]

Abstract Among the best-characterized genetic alterations in gliomas is the amplification of the epidermal growth factor receptor (EGFR) gene, present in ∼40% of glioblastoma multiforme, and frequently associated with the EGFRvIII gene rearrangement. We have previously shown that attenuated vaccine strains of measles virus have potent antitumor activity against gliomas, and identified H protein mutations, which ablate recognition of the natural measles virus receptors CD46 and SLAM. Retargeted recombinant viruses were generated from the measles Edmonston-NSe vaccine strain displaying a single-chain antibody against EGFRvIII at the COOH terminus of H and containing the marker green fluorescent protein (GFP) gene in position 1. Two different H mutants were employed: HSNS (V451S, Y481N, and A527S)-CD46 blind, and HAA (Y481A and R533A)-CD46 and SLAM blind. MV-GFP virus was used as a positive control. Both EGFRvIII-retargeted viruses had significant antitumor activity against EGFRvIII-expressing glioblastoma multiforme but no cytopathic effect against normal cells. In an orthotopic model of EGFRvIII-expressing GBM39 xenografts, there was comparable therapeutic efficacy between retargeted strains and unmodified MV-GFP and statistically significant prolongation of survival in treated animals compared with the control group (P = 0.001). Formation of syncytia was observed in tumors treated with retargeted viruses, with a surrounding infiltrate consisting of macrophages and natural killer cells. In summary, EGFRvIII-retargeted oncolytic measles virus strains have comparable therapeutic efficacy with the unmodified MV-GFP strain against EGFRvIII-expressing glioma lines and xenografts with improved therapeutic index, a finding with potential translational implications in glioma virotherapy. (Cancer Res 2006; 66(24): 11840-50)

Background Temsirolimus (CCI-779) is a small-molecule inhibitor of the mammalian target of rapamycin (mTOR) and represents a rational therapeutic target against glioblastoma multiforme (GBM). Methods Recurrent GBM patients with ≤ 1 chemotherapy regimen for progressive disease were eligible. Temsirolimus was administered in a 250-mg intravenous dose weekly. Results Sixty-five patients were treated. The incidence of grade 3 or higher nonhematologic toxicity was 51%, and consisted mostly of hypercholesterolemia (11%), hypertriglyceridemia (8%), and hyperglycemia (8%). Grade 3 hematologic toxicity was observed in 11% of patients. Temsirolimus peak concentration (Cmax), and sirolimus Cmax and area under the concentration-time curve were decreased in patients receiving p450 enzyme–inducing anticonvulsants (EIACs) by 73%, 47%, and 50%, respectively, but were still within the therapeutic range of preclinical models. Twenty patients (36%) had evidence of improvement in neuroimaging, consisting of decrease in T2 signal abnormality +/− decrease in T1 gadolinium enhancement, on stable or reduced steroid doses. Progression-free survival at 6 months was 7.8% and median overall survival was 4.4 months. Median time to progression (TTP) for all patients was 2.3 months and was significantly longer for responders (5.4 months) versus nonresponders (1.9 months). Development of grade 2 or higher hyperlipidemia in the first two treatment cycles was associated with a higher percentage of radiographic response (71% v 31%; P = .04). Significant correlation was observed between radiographic improvement and high levels of phosphorylated p70s6 kinase in baseline tumor samples (P = .04). Conclusion Temsirolimus is well tolerated in recurrent GBM patients. Despite the effect of EIACs on temsirolimus metabolism, therapeutic levels were achieved. Radiographic improvement was observed in 36% of temsirolimus–treated patients, and was associated with significantly longer TTP. High levels of phosphorylated p70s6 kinase in baseline tumor samples appear to predict a patient population more likely to derive benefit from treatment. These findings should be validated in other studies of mTOR inhibitors.

Purpose: We sought to determine the maximum-tolerated dose (MTD) and evaluate the toxicities and clinical activity of two irinotecan (CPT-11), fluorouracil (FU), leucovorin (LV), and oxaliplatin schedules in patients with advanced solid tumors. Additionally, we investigated the effect of CPT-11 on oxaliplatin pharmacokinetics. Patients and Methods: Thirteen patients (cohort 1) received intravenous CPT-11 (infusion) and FU/LV (bolus) on days 1, 8, 15, and 22 and oxaliplatin (infusion) on days 1 and 15 every 6 weeks for a total 37 courses (median, three courses) at three dose levels. Twenty-two cohort 2 patients received intravenous CPT-11/oxaliplatin (infusion, day 1) and FU/LV (90-minute bolus infusion, days 2 to 5) every 3 weeks for a total of 122 courses (median, four courses) at three dose levels. Pharmacokinetic and neurotoxicity assessments were performed at the cohort 2 MTD. Results: Dose-limiting toxicity (DLT) seen in both cohorts at the starting dose required dose de-escalation. Cohort 1 DLT included diarrhea and neutropenia. In cohort 2, diarrhea, vomiting, dehydration, neutropenia, febrile neutropenia, and paresthesias were DLTs. Antitumor activity was seen in both cohorts. In cohort 2, the total platinum area under the curve of patients increased 17% in cycle 2 (P = .048), but objective neurotoxicity was not seen. Conclusion: The toxicities resulting from the addition of oxaliplatin to CPT-11/FU/LV are significant but manageable. The MTDs for the weekly schedule are CPT-11 (75 mg/m2), oxaliplatin (50 mg/m2), FU (320 mg/m2), and LV (20 mg/m2); and, for the 3-weekly schedule, the MTDs are CPT-11 (175 mg/m2), oxaliplatin (85 mg/m2), FU (240 mg/m2), and LV (20 mg/m2). Second-cycle platinum accumulation raises the possibility for enhanced cumulative neurotoxicity with CPT-11/oxaliplatin combinations.

Purpose: To evaluate the antitumor activity, safety, immune response, and replication of CI-1042 (ONYX-015), an E1B 55-kd gene-deleted replication-selective adenovirus, administered intravenously to patients with metastatic colorectal cancer Patients and Methods: Eighteen patients with metastatic colorectal cancer for whom prior chemotherapy failed were enrolled onto an open-label, multicenter, phase II study. CI-1042 was administered intravenously at a dose of 2 × 1012 viral particles every 2 weeks. Patients were evaluated for tumor response and toxicity; in addition, blood samples were taken for adenovirus DNA and neutralizing antibody analysis. Results: Common toxicities included flu-like symptoms, nausea, and emesis. All 18 patients eventually were removed from study because of progressive disease. Seven patients were assessed as having stable disease after 2 months of treatment, whereas two patients were considered to have stable disease after 4 months. Detectable circulating CI-1042 DNA was identified in 36% of patients 72 hours after last infusion, which is suggestive of ongoing viral replication. Conclusion: In this phase II study, intravenous CI-1042 was administered safely to patients with advanced colorectal cancer. Toxicity was manageable, consisting primarily of flu-like symptoms. Stable disease was experienced by seven patients for 11 to 18 weeks.