Unmethylated Glioblastoma Research Articles

End of the road: confounding results of the CORE trial terminate the arduous journey of cilengitide for glioblastoma

End of the road: confounding results of the CORE trial terminate the arduous journey of cilengitide for glioblastoma

O6-methylguanine-DNA methyltransferase activity is associated with response to alkylating agent therapy and with MGMT promoter methylation in glioblastoma and anaplastic glioma

BackgroundCpG methylation in the O6-methylguanine-DNA methyltransferase (MGMT) promoter is associated with better outcome following alkylating agent chemotherapy in glioblastoma (GBM) and anaplastic glioma (AG). To what extent improved response reflects low or absent MGMT activity in glioma tissue has not been unequivocally assessed. This information is central to developing anti-resistance therapies. MethodsWe examined the relationship of MGMT activity in 91 GBMs and 84 AGs with progression-free survival (PFS) following alkylator therapy and with promoter methylation status determined by methylation-specific PCR (MSP). ResultsCox regression analysis revealed that GBMs with high activity had a significantly greater risk for progression in dichotomous (P≤0.001) and continuous (P≤0.003) models, an association observed for different alkylator regimens, including concurrent chemo-radiation with temozolomide. Analysis of MGMT promoter methylation status in 47 of the GBMs revealed that methylated tumors had significantly lower activity (P≤0.005) and longer PFS (P≤0.036) compared to unmethylated tumors, despite overlapping activities. PFS was also significantly greater in methylated vs. unmethylated GBMs with comparable activity (P≤0.005), and among unmethylated tumors with less than median activity (P≤0.026), suggesting that mechanisms in addition to MGMT promote alkylator resistance. Similar associations of MGMT activity with PFS and promoter methylation status were observed for AGs. ConclusionsOur results provide strong support for the hypotheses that MGMT activity promotes alkylator resistance and reflects promoter methylation status in malignant gliomas. General significanceMGMT activity is an attractive target for anti-resistance therapy regardless of methylation status.

Radiotherapy (RT), temozolomide (TMZ), procarbazine (PCB), and the integrin inhibitor cilengitide in patients (pts) with glioblastoma (GBM) without methylation of the MGMT gene promoter (ExCentric): Results of an Australian phase II clinical trial.

2050^ Background: Building on our preclinical data, we proposed that combination of low dose TMZ and PCB may overcome TMZ chemoresistance in MGMT unmethylated GBM. We proposed adding Cilengitide, a...

BTTC08-01: A phase II study of bevacizumab and erlotinib after radiation therapy and temozolomide in patients with newly diagnosed glioblastoma (GBM) without MGMT promoter methylation.

2019^ Background: Patients (pts) with GBM with unmethylated MGMT have a worse prognosis than those with methylated MGMT. Novel approaches for this poor risk group are warranted. The Brain Tumor Trials Collaborative (BTTC) performed a phase II trial evaluating standard chemoradiation followed by bevacizumab and erlotinib in patients with MGMT unmethylated GBM. EGFR and VEGFR are upregulated during radiation suggesting that this combination could be more effective than post-radiation adjuvant temozolomide (TMZ). Methods: After informed consent, adult patients with supratentorial GBM, KPS ≥ 70 and > 1 cm2 tumor block for MGMT promoter analysis were screened. Only tumors with confirmed unmethylated MGMT promoter were enrolled. All patients received RT + TMZ and then approximately 4 weeks after RT they received bevacizumab 10 mg/kg every 2 weeks and erlotinib 150 mg/day, continuously. One cycle was 4 weeks; evaluation by MRI was every 2 cycles. Treatment continued until disease progression or intolerable adverse events. Results: 115 patients were screened; 48 were enrolled (2 unevaluable: 1 for an infratentoral GBM and 1 withdrew after 7 days of treatment) with 29 men, 17 women. Median age was 56 yrs (29-75); median KPS was 90 (70-90). The median number of cycles was 8 (2-38) with 4 patients remaining on trial at the time of analysis. Objective responses: 4 CR, 12 PR and 30 SD. Median PFS is 7.3 months (95% CI (6.4, 11)) and median OS 14.2 months (95% CI (10.7, not reached)). There were no unexpected toxicities; grade 3/4 rate < 5%. Conclusions: Adjuvant bevacizumab and erlotinib in GBM with unmethylated MGMT is well tolerated. Preliminary efficacy data is comparable with outcomes in similar unmethylated MGMT patient populations from the EORTC/NCIC and RTOG 0525 studies. Tissue correlation is being performed. Clinical trial information: NCT00720356.

Epigenetic silencing of Id4 identifies a glioblastoma subgroup with a better prognosis as a consequence of an inhibition of angiogenesis

Inhibitors of DNA binding/differentiation (Id1 to Id4) are a family of helix-loop-helix transcription factors, which are highly expressed during embryogenesis and at lower levels in mature tissues. Id4 plays an important role in neuronal stem cell differentiation, and its deregulation has been implicated in glial neoplasia. The methylation status of Id4 was analyzed by methylation-specific polymerase chain reaction (PCR) in 62 glioblastoma (GBM) cases and in 20 normal brain tissues. Methylation status of Id4 was confirmed by sequencing after subcloning and messenger RNA (mRNA) and protein expression. We also evaluated the mRNA expression of MGP (matrix GLA protein), TGF-β1 (transforming growth factor beta 1), and VEGF (vascular endothelial growth factor) by real-time PCR analysis. Clinical and histological assessment of tumor angiogenesis was performed by evaluating the relative enhancing tumor ratio on magnetic resonance imaging and microvessel density on von Willebrand factor-stained sections, respectively. The promoter of Id4 was methylated in 23 of 62 (37%) GBMs. In methylated GBMs, Id4 mRNA was significantly reduced, compared with unmethylated GBMs (P = .0002). A significant reduction of protein expression was detected in all hypermethylated cases. GBMs with methylated Id4 showed a significant reduction of MGP, TGF-β1, and VEGF mRNA expression and had significantly lower relative enhancing tumor ratio (P = .0108) and microvessel density (P = .0241) values with respect to unmethylated GBMs. Finally, Id4 methylation was significantly associated with a favorable clinical outcome (P = .0006). These data suggest that methylation of Id4 may be involved in the pathogenesis of GBM and in the resistance of this neoplasm to conventional treatment throughout MGP-mediated neoangiogenesis.

Phase IB Study of Gene-Mediated Cytotoxic Immunotherapy Adjuvant to Up-Front Surgery and Intensive Timing Radiation for Malignant Glioma

Despite aggressive therapies, median survival for malignant gliomas is less than 15 months. Patients with unmethylated O(6)-methylguanine-DNA methyltransferase (MGMT) fare worse, presumably because of temozolomide resistance. AdV-tk, an adenoviral vector containing the herpes simplex virus thymidine kinase gene, plus prodrug synergizes with surgery and chemoradiotherapy, kills tumor cells, has not shown MGMT dependency, and elicits an antitumor vaccine effect. Patients with newly diagnosed malignant glioma received AdV-tk at 3 × 10(10), 1 × 10(11), or 3 × 10(11) vector particles (vp) via tumor bed injection at time of surgery followed by 14 days of valacyclovir. Radiation was initiated within 9 days after AdV-tk injection to overlap with AdV-tk activity. Temozolomide was administered after completing valacyclovir treatment. Accrual began December 2005 and was completed in 13 months. Thirteen patients were enrolled and 12 completed therapy, three at dose levels 1 and 2 and six at dose level 3. There were no dose-limiting or significant added toxicities. One patient withdrew before completing prodrug because of an unrelated surgical complication. Survival at 2 years was 33% and at 3 years was 25%. Patient-reported quality of life assessed with the Functional Assessment of Cancer Therapy-Brain (FACT-Br) was stable or improved after treatment. A significant CD3(+) T-cell infiltrate was found in four of four tumors analyzed after treatment. Three patients with MGMT unmethylated glioblastoma multiforme survived 6.5, 8.7, and 46.4 months. AdV-tk plus valacyclovir can be safely delivered with surgery and accelerated radiation in newly diagnosed malignant gliomas. Temozolomide did not prevent immune responses. Although not powered for efficacy, the survival and MGMT independence trends are encouraging. A phase II trial is ongoing.

CeCil: A randomized, noncomparative phase II clinical trial of the effect of radiation therapy (RT) plus temozolomide (TMZ) combined with cilengitide or cetuximab on the 1-year overall survival of patients with newly diagnosed MGMT-promoter unmethylated glioblastoma.

TPS134 Background: The overall survival (OS) of newly diagnosed glioblastoma (GB) patients (pts) treated with RT and TMZ is correlated with the methylation status of the MGMT-promoter. Pts with an unmethylated MGMT-promoter in particular have a poor prognosis and are in need of new active treatment options. Cilengitide, a selective αvβ3/5 integrin inhibitor, and cetuximab, a monoclonal EGFR-targeted antibody, have demonstrated anti-tumor activity against GB and can be safely combined with RT and TMZ. Methods: CeCil is an academia sponsored, multi-center, randomized phase II clinical trial of postoperative RT with daily concomitant TMZ (75 mg/m²/day) followed by 6 adjuvant cycles of TMZ (75-100 mg/m²/d x21d q 28d). Pts are randomized (1:1) to additional treatment with either cilengitide 2000 mg 2x weekly i.v., or cetuximab 1x weekly i.v. (400 mg/m² for the 1st administration and 250mg/m² for subsequent administrations). Cilengitide and cetuximab administration is started 1 week prior to RT/TMZ and is continued for up to 52 consecutive weeks in non-progressive pts. The 1-year OS-rate is the primary endpoint. Secondary endpoints include the PFS, and safety. Eligibility criteria include histologically confirmed, newly diagnosed GB without a methylated MGMT promoter (pts with an “unmethylated” or “invalid” test result are eligible), age ≥ 18 year, performance status of 0-1, and prior tumor resection or open biopsy. Recruitment is a 2-step process: after informed consent, histopathological diagnosis of glioblastoma and MGMT–promoter methylation status are centrally determined; GB-confirmed patients with an “unmethylated” or “invalid” test result are randomized (stratification by RPA classes: III vs. IV-V) between the two treatment arms. According to a one-stage Fleming design (a: 0.05; b: 0.05), with P0=60% and P1=80%, 54 pts will be recruited per study-arm. At least 39 pts must be alive at 12 months to validate the predefined hypothesis of activity. Accrual is ongoing in 7 medical centers in Belgium. ClinicalTrials.gov identifier: NCT01044225.

Long-term survival with unmethylated MGMT glioblastoma multiforme

Introduction: Glioblastoma multiforme is the most aggressive tumor of the central nervous system. Despite advances in its management, overall prognosis remains poor, with a median survival time of less than one year. Good response to chemotherapy with temozolomide (TMZ) is usually associated with methylation of the promoter of the O(6)-methylguanine-DNA methyltransferase ( MGMT ) gene. Case Report: We describe here a patient with glioblastoma multiforme, who had good prognostic clinical features, age and performance status, but unmethylated MGMT promoter and who survived for eight years while treated with a multi-modal approach. Conclusion: Good response to treatment, despite the absence of MGMT hypermethylation, suggests that other genetic or molecular factors may predict prognosis and therapeutic response in patients with glioblastoma multiforme.

An analysis of image texture, tumor location, and MGMT promoter methylation in glioblastoma using magnetic resonance imaging

In glioblastoma (GBM), promoter methylation of the DNA repair gene O6-methylguanine-DNA methyltransferase (MGMT) is associated with benefit from chemotherapy. Correlations between MGMT promoter methylation and visually assessed imaging features on magnetic resonance (MR) have been reported suggesting that noninvasive detection of MGMT methylation status might be possible. Our study assessed whether MGMT methylation status in GBM could be predicted using MR imaging. We conducted a retrospective analysis of MR images in patients with newly diagnosed GBM. Tumor texture was assessed by two methods. First, we analyzed texture by expert consensus describing the tumor borders, presence or absence of cysts, pattern of enhancement, and appearance of tumor signal in T2-weighted images. Then, we applied space–frequency texture analysis based on the S-transform. Tumor location within the brain was determined using automatized image registration and segmentation techniques. Their association with MGMT methylation was analyzed. We confirmed that ring enhancement assessed visually is significantly associated with unmethylated MGMT promoter status (P=0.006). Texture features on T2-weighted images assessed by the space–frequency analysis were significantly different between methylated and unmethylated cases (P<0.05). However, blinded classification of MGMT promoter methylation status reached an accuracy of only 71%. There were no significant differences in the locations of methylated and unmethylated GBM tumors. Our results provide further evidence that individual MR features are associated with MGMT methylation but better algorithms for predicting methylation status are needed. The relevance of this study lies on the application of novel techniques for the analysis of anatomical MR images of patients with GBM allowing the evaluation of subtleties not seen by an observer and facilitating the standardization of the methods, decreasing the potential for interobserver bias.