Median survival for glioblastoma (GBM) remains <15 months. Human cytomegalovirus (CMV) antigens have been identified in GBM but not normal brain, providing an unparalleled opportunity to subvert CMV ...antigens as tumor-specific immunotherapy targets. A recent trial in recurrent GBM patients demonstrated the potential clinical benefit of adoptive T-cell therapy (ATCT) of CMV phosphoprotein 65 (pp65)-specific T cells. However,
analyses from this study found no change in the capacity of CMV pp65-specific T cells to gain multiple effector functions or polyfunctionality, which has been associated with superior antitumor efficacy. Previous studies have shown that dendritic cells (DC) could further enhance tumor-specific CD8
T-cell polyfunctionality
when administered as a vaccine. Therefore, we hypothesized that vaccination with CMV pp65 RNA-loaded DCs would enhance the frequency of polyfunctional CMV pp65-specific CD8
T cells after ATCT. Here, we report prospective results of a pilot trial in which 22 patients with newly diagnosed GBM were initially enrolled, of which 17 patients were randomized to receive CMV pp65-specific T cells with CMV-DC vaccination (CMV-ATCT-DC) or saline (CMV-ATCT-saline). Patients who received CMV-ATCT-DC vaccination experienced a significant increase in the overall frequencies of IFNγ
, TNFα
, and CCL3
polyfunctional, CMV-specific CD8
T cells. These increases in polyfunctional CMV-specific CD8
T cells correlated (
= 0.7371,
= 0.0369) with overall survival, although we cannot conclude this was causally related. Our data implicate polyfunctional T-cell responses as a potential biomarker for effective antitumor immunotherapy and support a formal assessment of this combination approach in a larger randomized study.
A randomized pilot trial in patients with GBM implicates polyfunctional T-cell responses as a biomarker for effective antitumor immunotherapy.
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Identifying strong markers of prognosis are critical to optimize treatment and survival outcomes in patients with malignant recurrent glioma. We investigated the prognostic significance of exercise ...behavior and functional capacity in this population.
Using a prospective design, 243 patients with WHO grades 3 to 4 recurrent malignant glioma and Karnofsky performance status (KPS) ≥ 70 completed a self-administered questionnaire that assessed exercise behavior and performed a 6-minute walk test (6MWT) to assess functional capacity. Cox proportional models were used to estimate the risk of all-cause mortality according to 6MWT distance (6MWD; < 390 meters, 390-489 meters, > 489 meters) and exercise behavior (metabolic equivalent MET -h/wk) adjusted for KPS and other important clinical factors.
Median follow-up was 27.43 months. During this period, 149 deaths were recorded (61% of the total sample). Exercise behavior was an independent predictor of survival (P = .0081). Median survival was 13.03 months for patients reporting < 9 MET-h/wk relative to 21.84 months for those reporting ≥ 9 MET-h/wk. Exercise behavior added incremental prognostic value beyond that provided by KPS, age, sex, grade, and number of prior progressions (P < .001). Compared with patients reporting < 9 MET-h/wk, the adjusted hazard ratio for mortality was 0.64 (95% CI, 0.46 to 0.91) for patients reporting ≥ 9 MET-h/wk. Functional capacity was not an independent predictor of prognosis.
Exercise behavior is a strong independent predictor of survival that provides incremental prognostic value to KPS as well as traditional markers of prognosis in malignant recurrent glioma.
Epidermal growth factor receptor variant III (EGFRvIII) is a tumor-specific mutation widely expressed in glioblastoma multiforme (GBM) and other neoplasms, but absent from normal tissues. ...Immunotherapeutic targeting of EGFRvIII could eliminate neoplastic cells more precisely but may be inhibited by concurrent myelosuppressive chemotherapy like temozolomide (TMZ), which produces a survival benefit in GBM. A phase II, multicenter trial was undertaken to assess the immunogenicity of an experimental EGFRvIII-targeted peptide vaccine in patients with GBM undergoing treatment with serial cycles of standard-dose (STD) (200 mg/m2 per 5 days) or dose-intensified (DI) TMZ (100 mg/m2 per 21 days). All patients receiving STD TMZ exhibited at least a transient grade 2 lymphopenia, whereas those receiving DI TMZ exhibited a sustained grade 3 lymphopenia (<500 cells/μL). CD3+ T-cell (P = .005) and B-cell (P = .004) counts were reduced significantly only in the DI cohort. Patients in the DI cohort had an increase in the proportion of immunosuppressive regulatory T cells (T
Reg; P = .008). EGFRvIII-specific immune responses developed in all patients treated with either regimen, but the DI TMZ regimen produced humoral (P = .037) and delayed-type hypersensitivity responses (P = .036) of greater magnitude. EGFRvIII-expressing tumor cells were also eradicated in nearly all patients (91.6%; CI95: 64.0%-99.8%; P < .0001). The median progression-free survival (15.2 months; CI95: 11.0-18.5 months; hazard ratio HR = 0.35; P = .024) and overall survival (23.6 months; CI95: 18.5-33.1 months; HR = 0.23; P = .019) exceeded those of historical controls matched for entry criteria and adjusted for known prognostic factors. EGFRvIII-targeted vaccination induces patient immune responses despite therapeutic TMZ-induced lymphopenia and eliminates EGFRvIII-expressing tumor cells without autoimmunity.
Malignant gliomas, including the most common subtype, glioblastoma multiforme (GBM), are among the most devastating of neoplasms. Their aggressive infiltration in the CNS typically produces ...progressive and profound disability--ultimately leading to death in nearly all cases. Improvement in outcome has been elusive despite decades of intensive clinical and laboratory research. Surgery and radiotherapy, the traditional cornerstones of therapy, provide palliative benefit, while the value of chemotherapy has been marginal and controversial. Limited delivery and tumor heterogeneity are two fundamental factors that have critically hindered therapeutic progress. A novel chemoradiotherapy approach, consisting of temozolomide administered concurrently during radiotherapy followed by adjuvant systemic temozolomide, has recently demonstrated a meaningful, albeit modest, improvement in overall survival for newly diagnosed GBM patients. As cell-signaling alterations linked to the development and progression of gliomas are being increasingly elucidated, targeted therapies have rapidly entered preclinical and clinical evaluation. Responses to therapies that function via DNA damage have been associated with specific mediators of resistance that may also be subject to targeted therapies. Other approaches include novel locoregional delivery techniques to overcome barriers of delivery. The simultaneous development of multiple advanced therapies based on specific tumor biology may finally offer glioma patients improved survival.
A phase II study of bevacizumab (BVZ) plus irinotecan (CPT-11) was conducted in children with recurrent malignant glioma (MG) and intrinsic brainstem glioma (BSG).
Eligible patients received two ...doses of BVZ intravenously (10 mg/kg) 2 weeks apart and then BVZ plus CPT-11 every 2 weeks until progressive disease, unacceptable toxicity, or a maximum of 2 years of therapy. Correlative studies included diffusion weighted and T1 dynamic contrast-enhanced permeability imaging, BVZ pharmacokinetics, and estimation of vascular endothelial growth factor receptor 2 (VEGFR-2) phosphorylation in peripheral blood mononuclear cells (PBMC) after single-agent BVZ.
Thirty-one evaluable patients received a median of two courses of BVZ plus CPT-11 (range, 1 to 19). No sustained responses were observed in either stratum. Median time to progression for all 34 eligible patients enrolled was 127 days for MG and 71 days for BSG. Progression-free survival rates at 6 months were 41.8% and 9.7% for MG and BSG, respectively. Toxicities related to BVZ included grade 1 to 3 fatigue in seven patients, grade 1 to 2 hypertension in seven patients, grade 1 CNS hemorrhage in four patients, and grade 4 CNS ischemia in two patients. The mean diffusion ratio decreased after two doses of BVZ in patients with MG only. Vascular permeability parameters did not change significantly after therapy in either stratum. Inhibition of VEGFR-2 phosphorylation in PBMC was detected in eight of 11 patients after BVZ exposure.
BVZ plus CPT-11 was well-tolerated but had minimal efficacy in children with recurrent malignant glioma and brainstem glioma.
The combination of a vascular endothelial growth factor (VEGF) -neutralizing antibody, bevacizumab, and irinotecan is associated with high radiographic response rates and improved survival outcomes ...in patients with recurrent malignant gliomas. The aim of these retrospective studies was to evaluate tumor vascularity and expression of components of the VEGF pathway and hypoxic responses as predictive markers for radiographic response and survival benefit from the bevacizumab and irinotecan therapy.
In a phase II trial, 60 patients with recurrent malignant astrocytomas were treated with bevacizumab and irinotecan. Tumor specimens collected at the time of diagnosis were available for further pathologic studies in 45 patients (75%). VEGF, VEGF receptor-2, CD31, hypoxia-inducible carbonic anhydrase 9 (CA9), and hypoxia-inducible factor-2alpha were semiquantitatively assessed by immunohistochemistry. Radiographic response and survival outcomes were correlated with these angiogenic and hypoxic markers.
Of 45 patients, 27 patients had glioblastoma multiforme, and 18 patients had anaplastic astrocytoma. Twenty-six patients (58%) had at least partial radiographic response. High VEGF expression was associated with increased likelihood of radiographic response (P = .024) but not survival benefit. Survival analysis revealed that high CA9 expression was associated with poor survival outcome (P = .016).
In this patient cohort, tumor expression levels of VEGF, the molecular target of bevacizumab, were associated with radiographic response, and the upstream promoter of angiogenesis, hypoxia, determined survival outcome, as measured from treatment initiation. Validation in a larger clinical trial is warranted.
Object
Convection-enhanced delivery (CED) is a novel intracerebral drug delivery technique with considerable promise for delivering therapeutic agents throughout the CNS. Despite this promise, Phase ...III clinical trials employing CED have failed to meet clinical end points. Although this may be due to inactive agents or a failure to rigorously validate drug targets, the authors have previously demonstrated that catheter positioning plays a major role in drug distribution using this technique. The purpose of the present work was to retrospectively analyze the expected drug distribution based on catheter positioning data available from the CED arm of the PRECISE trial.
Methods
Data on catheter positioning from all patients randomized to the CED arm of the PRECISE trial were available for analyses. BrainLAB iPlan Flow software was used to estimate the expected drug distribution.
Results
Only 49.8% of catheters met all positioning criteria. Still, catheter positioning score (hazard ratio 0.93, p = 0.043) and the number of optimally positioned catheters (hazard ratio 0.72, p = 0.038) had a significant effect on progression-free survival. Estimated coverage of relevant target volumes was low, however, with only 20.1% of the 2-cm penumbra surrounding the resection cavity covered on average. Although tumor location and resection cavity volume had no effect on coverage volume, estimations of drug delivery to relevant target volumes did correlate well with catheter score (p < 0.003), and optimally positioned catheters had larger coverage volumes (p < 0.002). Only overall survival (p = 0.006) was higher for investigators considered experienced after adjusting for patient age and Karnofsky Performance Scale score.
Conclusions
The potential efficacy of drugs delivered by CED may be severely constrained by ineffective delivery in many patients. Routine use of software algorithms and alternative catheter designs and infusion parameters may improve the efficacy of drugs delivered by CED.
Malignant
gliomas (glioblastoma multiforme and anaplastic astrocytoma) occur more
frequently than other types of primary central nervous system tumors,
having a combined incidence of 5–8/100,000 ...population. Even with
aggressive treatment using surgery, radiation, and chemotherapy, median
reported survival is less than 1 year. Temozolomide, a new drug, has
shown promise in treating malignant gliomas and other
difficult-to-treat tumors.
Temozolomide, a p.o. imidazotetrazine second-generation alkylating
agent, is the leading compound in a new class of chemotherapeutic
agents that enter the cerebrospinal fluid and do not require hepatic
metabolism for activation. In vitro, temozolomide has
demonstrated schedule-dependent antitumor activity against highly
resistant malignancies, including high-grade glioma. In clinical
studies, temozolomide consistently demonstrates reproducible linear
pharmacokinetics with approximately 100% p.o. bioavailability,
noncumulative minimal myelosuppression that is rapidly reversible, and
activity against a variety of solid tumors in both children and adults.
Preclinical studies have evaluated the combination of temozolomide with
other alkylating agents and inhibitors of the DNA repair protein
O 6 -alkylguanine alkyltransferase to overcome
resistance to chemotherapy in malignant glioma and malignant metastatic
melanoma. Temozolomide has recently been approved in the United States
for the treatment of adult patients with refractory anaplastic
astrocytoma and, in the European Union, for treatment of glioblastoma
multiforme showing progression or recurrence after standard therapy.
Predictable bioavailability and minimal toxicity make temozolomide a
candidate for a wide range of clinical testing to evaluate the
potential of combination treatments in different tumor types. An
overview of the mechanism of action of temozolomide and a summary of
results from clinical trials in malignant glioma are presented here.
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