The methylation status of the O
-methylguanine DNA methyltransferase (
) gene promoter is predictive for benefit from temozolomide in glioblastoma (GBM). A clinically optimized cutoff was sought ...allowing patient selection for therapy without temozolomide, while avoiding to withhold it from patients who may potentially benefit.
Quantitative
methylation-specific PCR data were obtained for newly diagnosed patients with GBM screened or treated with standard radiotherapy and temozolomide in four randomized trials. The pooled dataset was randomly split into a training and test dataset. The unsupervised cutoff was obtained at a 50% probability to be (un)methylated. ROC analysis identified an optimal cutoff supervised by overall survival (OS).
For 4,041 patients valid
results were obtained, whereof 1,725 were randomized. The unsupervised cutoff in the training dataset was 1.27 (log
1,000 × (
+1)/
), separating unmethylated and methylated patients. The optimal supervised cutoff for unmethylated patients was -0.28 (AUC = 0.61), classifying "truly unmethylated" (≤-0.28) and "gray zone" patients (>-0.28, ≤1.27), the latter comprising approximately 10% of cases. In contrast, for patients with
methylation (>1.27) more methylation was not related to better outcome. Both methylated and gray zone patients performed significantly better for OS than truly unmethylated patients HR = 0.35, 95% confidence interval (CI), 0.27-0.45,
< 0.0001; HR = 0.58, 95% CI, 0.43-0.78,
< 0.001, validated in the test dataset. The MGMT assay was highly reproducible upon retesting of 218 paired samples (
= 0.94).
Low
methylation (gray zone) may confer some sensitivity to temozolomide treatment, hence the lower safety margin should be considered for selecting patients with unmethylated GBM into trials omitting temozolomide.
Radiation with concurrent and adjuvant (6 cycles) temozolomide (TMZ) is the established standard of postsurgical care for newly diagnosed glioblastoma (GBM). This regimen has been adopted with ...variations, including extending TMZ beyond 6 cycles. The optimal duration of maintenance therapy remains controversial.
We performed pooled analysis of individual patient data from 4 randomized trials for newly diagnosed GBM. All patients who were progression free 28 days after cycle 6 were included. The decision to continue TMZ was per local practice and standards, and at the discretion of the treating physician. Patients were grouped into those treated with 6 cycles and those who continued beyond 6 cycles. Progression-free and overall survival were compared, adjusted by age, performance status, resection extent, and MGMT methylation.
A total of 2214 GBM patients were included in the 4 trials. Of these, 624 qualified for analysis 291 continued maintenance TMZ until progression or up to 12 cycles, while 333 discontinued TMZ after 6 cycles. Adjusted for prognostic factors, treatment with more than 6 cycles of TMZ was associated with a somewhat improved progression-free survival (hazard ratio HR 0.80 0.65-0.98, P = .03), in particular for patients with methylated MGMT (n = 342, HR 0.65 0.50-0.85, P < .01). However, overall survival was not affected by the number of TMZ cycles (HR = 0.92 0.71-1.19, P = .52), including the MGMT methylated subgroup (HR = 0.89 0.63-1.26, P = .51).
Continuing TMZ beyond 6 cycles was not shown to increase overall survival for newly diagnosed GBM.
Symptomatic epilepsy is a common complication of glioblastoma and requires pharmacotherapy. Several uncontrolled retrospective case series and a post hoc analysis of the registration trial for ...temozolomide indicated an association between valproic acid (VPA) use and improved survival outcomes in patients with newly diagnosed glioblastoma.
To confirm the hypothesis suggested above, a combined analysis of survival association of antiepileptic drug use at the start of chemoradiotherapy with temozolomide was performed in the pooled patient cohort (n = 1,869) of four contemporary randomized clinical trials in newly diagnosed glioblastoma: AVAGlio (Avastin in Glioblastoma; NCT00943826), CENTRIC (Cilengitide, Temozolomide, and Radiation Therapy in Treating Patients With Newly Diagnosed Glioblastoma and Methylated Gene Promoter Status; NCT00689221), CORE (Cilengitide, Temozolomide, and Radiation Therapy in Treating Patients With Newly Diagnosed Glioblastoma and Unmethylated Gene Promoter Status; NCT00813943), and Radiation Therapy Oncology Group 0825 (NCT00884741). Progression-free survival (PFS) and overall survival (OS) were compared between: (1) any VPA use and no VPA use at baseline or (2) VPA use both at start of and still after chemoradiotherapy. Results of Cox regression models stratified by trial and adjusted for baseline prognostic factors were analyzed. The same analyses were performed with levetiracetam (LEV).
VPA use at start of chemoradiotherapy was not associated with improved PFS or OS compared with all other patients pooled (PFS: hazard ratio HR, 0.91; 95% CI, 0.77 to 1.07; P = .241; OS: HR, 0.96; 95% CI, 0.80 to 1.15; P = .633). Furthermore, PFS and OS of patients taking VPA both at start of and still after chemoradiotherapy were not different from those without antiepileptic drug use at both time points (PFS: HR, 0.92; 95% CI, 0.74 to 1.15; P = .467; OS: HR, 1.10; 95% CI, 0.86 to 1.40; P = .440). Similarly, no association with improved outcomes was observed for LEV use.
The results of this analysis do not justify the use of VPA or LEV for reasons other than seizure control in patients with newly diagnosed glioblastoma outside clinical trials.
With rapid advances in genomic medicine, the complexity of delivering precision medicine to oncology patients across a university health system demanded the creation of a Molecular Tumor Board (MTB) ...for patient selection and assessment of treatment options. The objective of this report is to analyze our progress to date and discuss the importance of the MTB in the implementation of personalized medicine.
Patients were reviewed in the MTB for appropriateness for comprehensive next generation sequencing (NGS) cancer gene set testing based on set criteria that were in place. Because profiling of stage IV lung cancer, colon cancer, and melanoma cancers were standard of care, these cancer types were excluded from this process. We subsequently analyzed the types of cases referred for testing and approved with regards to their results.
191 cases were discussed at the MTB and 132 cases were approved for testing. Forty-six cases (34.8%) had driver mutations that were associated with an active targeted therapeutic agent, including
, and
. An additional 56 cases (42.4%) had driver mutations previously reported in some type of cancer. Twenty-two cases (16.7%) did not have any clinically significant mutations. Eight cases did not yield adequate DNA. 15 cases were considered for targeted therapy, 13 of which received targeted therapy. One patient experienced a near complete response. Seven of 13 had stable disease or a partial response.
MTB at University of Alabama-Birmingham is unique because it reviews the appropriateness of NGS testing for patients with recurrent cancer and serves as a forum to educate our physicians about the pathways of precision medicine. Our results suggest that our detection of actionable mutations may be higher due to our careful selection. The application of precision medicine and molecular genetic testing for cancer patients remains a continuous educational process for physicians.
A major hallmark of neuroinflammation is the activation of microglia and astrocytes with the induction of inflammatory mediators such as IL‐1β, TNF‐α, iNOS, and IL‐6. Neuroinflammation contributes to ...disease progression in a plethora of neurological disorders ranging from acute CNS trauma to chronic neurodegenerative disease. Posttranscriptional pathways of mRNA stability and translational efficiency are major drivers for the expression of these inflammatory mediators. A common element in this level of regulation centers around the adenine‐ and uridine‐rich element (ARE) which is present in the 3′ untranslated region (UTR) of the mRNAs encoding these inflammatory mediators. (ARE)‐binding proteins (AUBPs) such as Human antigen R (HuR), Tristetraprolin (TTP) and KH‐ type splicing regulatory protein (KSRP) are key nodes for directing these posttranscriptional pathways and either promote (HuR) or suppress (TTP and KSRP) glial production of inflammatory mediators. This review will discuss basic concepts of ARE‐mediated RNA regulation and its impact on glial‐driven neuroinflammatory diseases. We will discuss strategies to target this novel level of gene regulation for therapeutic effect and review exciting preliminary studies that underscore its potential for treating neurological disorders.
Main Point
Review mechanisms of RNA regulation of glial neuroinflammatory responses
This multi-institutional phase I trial was designed to determine the maximum-tolerated dose (MTD) of cilengitide (EMD 121974) and to evaluate the use of perfusion magnetic resonance imaging (MRI) in ...patients with recurrent malignant glioma.
Patients received cilengitide twice weekly on a continuous basis. A treatment cycle was defined as 4 weeks. Treatment-related dose-limiting toxicity (DLT) was defined as any grade 3 or 4 nonhematologic toxicity or grade 4 hematologic toxicity of any duration.
A total of 51 patients were enrolled in cohorts of six patients to doses of 120, 240, 360, 480, 600, 1,200, 1,800, and 2,400 mg/m2 administered as a twice weekly intravenous infusion. Three patients progressed early and were inevaluable for toxicity assessment. The DLTs observed were one thrombosis (120 mg/m2), one grade 4 joint and bone pain (480 mg/m2), one thrombocytopenia (600 mg/m2) and one anorexia, hypoglycemia, and hyponatremia (800 mg/m2). The MTD was not reached. Two patients demonstrated complete response, three patients had partial response, and four patients had stable disease. Perfusion MRI revealed a significant relationship between the change in tumor relative cerebral blood flow (rCBF) from baseline and area under the plasma concentration versus time curve after 16 weeks of therapy.
Cilengitide is well tolerated to doses of 2,400 mg/m2, durable complete and partial responses were seen in this phase I study, and clinical response appears related to rCBF changes.
Glioblastomas are malignant brain tumors with poor prognosis. Lately, data from clinical studies assessing the role of co-medications in different cancer types suggested reduced mortality and ...potential anti-tumor activity for statins, angiotensin-I converting enzyme inhibitors (ACEI) and angiotensin II receptor blockers (sartans). Here, we analysed the association of co-treatment with statins, ACEI or sartans with outcome in a cohort of 810 patients enrolled in the phase III CENTRIC and phase II CORE trials on the role of the integrin antagonist, cilengitide, in newly diagnosed glioblastoma with or without O
6
-methylguanine DNA methyltransferase (
MGMT
) promoter methylation. Progression-free survival (PFS) and overall survival (OS) were analysed for each medication in the pooled patient group. No association was found for co-medication with either drug for PFS or OS. Median OS was 22.1 (statins) versus 22.2 (control) months (HR 1.06, 95% CI 0.81–1.39, p = 0.69), 20.4 (ACEI) versus 22.6 (control) months (HR 1.25, 95% CI 0.96–1.62, p = 0.10), and 21.7 (sartans) versus 22.3 (control) months (HR 0.86, 95% CI 0.61–1.21, p = 0.38). None of the comparisons showed a signal for different PFS or OS when analyses were controlled for
MGMT
promoter methylation or treatment group (TMZ/RT → TMZ vs. RT + CIL + TMZ → TMZ + CIL). This secondary analysis of two large glioblastoma trials thus was unable to detect evidence for an association of the use of statins, ACEI or sartans with outcome in patients with newly diagnosed glioblastoma. These data challenge the rationale for prospective studies on the possible role of these non-tumor-specific drugs within the concept of drug repurposing.
Introduction
Hypoxia inducible factor 2-alpha (HIF2α) mediates cellular responses to hypoxia and is over-expressed in glioblastoma (GBM). PT2385 is an oral HIF2α inhibitor with in vivo activity ...against GBM.
Methods
A two-stage single-arm open-label phase II study of adults with GBM at first recurrence following chemoradiation with measurable disease was conducted through the Adult Brain Tumor Consortium. PT2385 was administered at the phase II dose (800 mg b.i.d.). The primary outcome was objective radiographic response (ORR = complete response + partial response, CR + PR); secondary outcomes were safety, overall survival (OS), and progression free survival (PFS). Exploratory objectives included pharmacokinetics (day 15 C
min
), pharmacodynamics (erythropoietin, vascular endothelial growth factor), and pH-weighted amine- chemical exchange saturation transfer (CEST) MRI to quantify tumor acidity at baseline and explore associations with drug response. Stage 1 enrolled 24 patients with early stoppage for ≤ 1 ORR.
Results
Of the 24 enrolled patients, median age was 62.1 (38.7–76.7) years, median KPS 80, MGMT promoter was methylated in 46% of tumors. PT2385 was well tolerated. Grade ≥ 3 drug-related adverse events were hypoxia (n = 2), hyponatremia (2), lymphopenia (1), anemia (1), and hyperglycemia (1). No objective radiographic responses were observed; median PFS was 1.8 months (95% CI 1.6–2.5) and OS was 7.7 months (95% CI 4.9–12.6). Drug exposure varied widely and did not differ by corticosteroid use (p = 0.12), antiepileptics (p = 0.09), or sex (p = 0.37). Patients with high systemic exposure had significantly longer PFS (6.7 vs 1.8 months, p = 0.009). Baseline acidity by pH-weighted CEST MRI correlated significantly with treatment duration (R
2
= 0.49, p = 0.017). Non-enhancing infiltrative disease with high acidity gave rise to recurrence.
Conclusions
PT2385 monotherapy had limited activity in first recurrent GBM. Drug exposure was variable. Signals of activity were observed in GBM patients with high systemic exposure and acidic lesions on CEST imaging. A second-generation HIF2α inhibitor is being studied.
Glioblastoma (GBM) is a lethal disease with no effective therapies available. We previously observed upregulation of the TAM (Tyro-3, Axl, and Mer) receptor tyrosine kinase family member AXL in ...mesenchymal GBM and showed that knockdown of AXL induced apoptosis of mesenchymal, but not proneural, glioma sphere cultures (GSC). In this study, we report that BGB324, a novel small molecule inhibitor of AXL, prolongs the survival of immunocompromised mice bearing GSC-derived mesenchymal GBM-like tumors. We show that protein S (PROS1), a known ligand of other TAM receptors, was secreted by tumor-associated macrophages/microglia and subsequently physically associated with and activated AXL in mesenchymal GSC. PROS1-driven phosphorylation of AXL (pAXL) induced NFκB activation in mesenchymal GSC, which was inhibited by BGB324 treatment. We also found that treatment of GSC-derived mouse GBM tumors with nivolumab, a blocking antibody against the immune checkpoint protein PD-1, increased intratumoral macrophages/microglia and activation of AXL. Combinatorial therapy with nivolumab plus BGB324 effectively prolonged the survival of mice bearing GBM tumors. Clinically, expression of AXL or PROS1 was associated with poor prognosis for patients with GBM. Our results suggest that the PROS1-AXL pathway regulates intrinsic mesenchymal signaling and the extrinsic immune microenvironment, contributing to the growth of aggressive GBM tumors.
These findings suggest that development of combination treatments of AXL and immune checkpoint inhibitors may provide benefit to patients with GBM.
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