Abstract 6779: Spatial and single-nucleus transcriptomics of human glioblastoma

Glioblastoma (GBM) multiforme is the most aggressive type of brain cancer. These lethal brain tumors are characterized by the inter- and intra-tumor molecular heterogeneity and diverse cell plasticity. We sought to interrogate the immune landscape of GBM, tease out the distinct biological and therapeutic niches in GBM and to understand how the tumor microenvironments mediated the heterogeneity of GBM. We have collected six human GBM samples for spatial profiling and single-nucleus RNA sequencing. Multiple sets of spatial gene panels were designed to capture the cell identities (cancer stem cells, astrocytes, oligodendrocytes, microglia, macrophages, endothelial cells, etc.) and the spatially-resolved expression patterns of genes indicative of different functional states. We also aim to find altered neurovascular units by examining the spatial correlation between cells that highly express angiogenesis markers such as VEGFA with tumor-associated macrophages, which could be recruited to the angiogenic niche by GBM tumor cells. From the spatial RNA dataset of the first two samples, we observed close proximity of tumor-associated macrophages and endothelial cells that form the microvasculature. Our preliminary results from the single-nucleus RNA sequencing and spatial transcriptomics of two samples shed light on the complex cell landscape and the dynamic interaction between tumor cells and infiltrating or resident immune cells in the GBM tumor tissue.

Citation Format: Yue Hao, Angela Baker, Brian Hilbush, Marcos Otero, Chris Streck, Karen L. Fink, George J. Snipes, Bruce E. Mickey, Michael Berens. Spatial and single-nucleus transcriptomics of human glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6779.

Association of Autologous Tumor Lysate-Loaded Dendritic Cell Vaccination With Extension of Survival Among Patients With Newly Diagnosed and Recurrent Glioblastoma: A Phase 3 Prospective Externally Controlled Cohort Trial

Importance

Glioblastoma is the most lethal primary brain cancer. Clinical outcomes for glioblastoma remain poor, and new treatments are needed.

Objective

To investigate whether adding autologous tumor lysate-loaded dendritic cell vaccine (DCVax-L) to standard of care (SOC) extends survival among patients with glioblastoma.

Design, Setting, and Participants

This phase 3, prospective, externally controlled nonrandomized trial compared overall survival (OS) in patients with newly diagnosed glioblastoma (nGBM) and recurrent glioblastoma (rGBM) treated with DCVax-L plus SOC vs contemporaneous matched external control patients treated with SOC. This international, multicenter trial was conducted at 94 sites in 4 countries from August 2007 to November 2015. Data analysis was conducted from October 2020 to September 2021.

Interventions

The active treatment was DCVax-L plus SOC temozolomide. The nGBM external control patients received SOC temozolomide and placebo; the rGBM external controls received approved rGBM therapies.

Main Outcomes and Measures

The primary and secondary end points compared overall survival (OS) in nGBM and rGBM, respectively, with contemporaneous matched external control populations from the control groups of other formal randomized clinical trials.

Results

A total of 331 patients were enrolled in the trial, with 232 randomized to the DCVax-L group and 99 to the placebo group. Median OS (mOS) for the 232 patients with nGBM receiving DCVax-L was 19.3 (95% CI, 17.5-21.3) months from randomization (22.4 months from surgery) vs 16.5 (95% CI, 16.0-17.5) months from randomization in control patients (HR = 0.80; 98% CI, 0.00-0.94; P = .002). Survival at 48 months from randomization was 15.7% vs 9.9%, and at 60 months, it was 13.0% vs 5.7%. For 64 patients with rGBM receiving DCVax-L, mOS was 13.2 (95% CI, 9.7-16.8) months from relapse vs 7.8 (95% CI, 7.2-8.2) months among control patients (HR, 0.58; 98% CI, 0.00-0.76; P < .001). Survival at 24 and 30 months after recurrence was 20.7% vs 9.6% and 11.1% vs 5.1%, respectively. Survival was improved in patients with nGBM with methylated MGMT receiving DCVax-L compared with external control patients (HR, 0.74; 98% CI, 0.55-1.00; P = .03).

Conclusions and Relevance

In this study, adding DCVax-L to SOC resulted in clinically meaningful and statistically significant extension of survival for patients with both nGBM and rGBM compared with contemporaneous, matched external controls who received SOC alone.

Trial Registration

ClinicalTrials.gov Identifier: NCT00045968.

Joint Final Report of EORTC 26951 and RTOG 9402: Phase III Trials With Procarbazine, Lomustine, and Vincristine Chemotherapy for Anaplastic Oligodendroglial Tumors

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the basis of the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.Anaplastic oligodendroglial tumors (AOTs) are chemotherapy-sensitive brain tumors. We report the final very long-term survival results from European Organization for the Research and Treatment of Cancer 26951 and Radiation Therapy Oncology Group 9402 phase III trials initiated in 1990s, which both studied radiotherapy with/without neo/adjuvant procarbazine, lomustine, and vincristine (PCV) for newly diagnosed anaplastic oligodendroglial tumors. The median follow-up duration in both was 18-19 years. For European Organization for the Research and Treatment of Cancer 26951, median, 14-year, and probable 20-year overall survival rates without versus with PCV were 2.6 years, 13.4%, and 10.1% versus 3.5 years, 25.1%, and 16.8% (N = 368 overall; hazard ratio [HR] 0.78; 95% CI, 0.63 to 0.98; P = .033), with 1p19q codeletion 9.3 years, 26.2%, and 13.6% versus 14.2 years, 51.0%, and 37.1% (n = 80; HR 0.60; 95% CI, 0.35 to 1.03; P = .063), respectively. For Radiation Therapy Oncology Group 9402, analogous results were 4.8 years, 16.5%, and 11.2% versus 4.8 years, 29.1%, and 24.6% (N = 289 overall; HR 0.79; 95% CI, 0.61 to 1.03; P = .08), with codeletion 7.3 years, 25.0%, and 14.9% versus 13.2 years, 46.1%, and 37% (n = 125; HR 0.61; 95% CI, 0.40 to 0.94; P = .02), respectively. With that, the studies show similar long-term survival even without tumor recurrence in a significant proportion of patients after first-line treatment with radiotherapy/PCV.

First results on survival from a large Phase 3 clinical trial of an autologous dendritic cell vaccine in newly diagnosed glioblastoma

Background

Standard therapy for glioblastoma includes surgery, radiotherapy, and temozolomide. This Phase 3 trial evaluates the addition of an autologous tumor lysate-pulsed dendritic cell vaccine (DCVax^®-L) to standard therapy for newly diagnosed glioblastoma.

Methods

After surgery and chemoradiotherapy, patients were randomized (2:1) to receive temozolomide plus DCVax-L (n = 232) or temozolomide and placebo (n = 99). Following recurrence, all patients were allowed to receive DCVax-L, without unblinding. The primary endpoint was progression free survival (PFS); the secondary endpoint was overall survival (OS).

Results

For the intent-to-treat (ITT) population (n = 331), median OS (mOS) was 23.1 months from surgery. Because of the cross-over trial design, nearly 90% of the ITT population received DCVax-L. For patients with methylated MGMT (n = 131), mOS was 34.7 months from surgery, with a 3-year survival of 46.4%. As of this analysis, 223 patients are ≥ 30 months past their surgery date; 67 of these (30.0%) have lived ≥ 30 months and have a Kaplan-Meier (KM)-derived mOS of 46.5 months. 182 patients are ≥ 36 months past surgery; 44 of these (24.2%) have lived ≥ 36 months and have a KM-derived mOS of 88.2 months. A population of extended survivors (n = 100) with mOS of 40.5 months, not explained by known prognostic factors, will be analyzed further. Only 2.1% of ITT patients (n = 7) had a grade 3 or 4 adverse event that was deemed at least possibly related to the vaccine. Overall adverse events with DCVax were comparable to standard therapy alone.

Conclusions

Addition of DCVax-L to standard therapy is feasible and safe in glioblastoma patients, and may extend survival.

Trial registration Funded by Northwest Biotherapeutics; Clinicaltrials.gov number: NCT00045968; https://clinicaltrials.gov/ct2/show/NCT00045968?term=NCT00045968&rank=1; initially registered 19 September 2002

Phase 1b open-label randomized study of the oncolytic adenovirus DNX-2401 administered with or without interferon gamma for recurrent glioblastoma

2002

Background: DNX-2401 is a replication-competent, tumor-selective, oncolytic adenovirus with enhanced infectivity that causes durable tumor control by killing tumor cells and eliciting antitumor immunity. To increase immune activation, a phase 1b randomized study of intratumoral DNX-2401 alone versus DNX-2401 with interferon gamma (IFN) was conducted. Methods: A total of 27 patients with biopsy-confirmed glioblastoma at first or second recurrence received a single intratumoral injection of 3e10 vp DNX-2401. Patients were randomized in a 2:1 ratio to receive 50 mcg/m2 of subcutaneous IFN (Actimmune) Q3W initiated 14 days after DNX-2401 or to be followed without further treatment for safety and survival. Results: Twenty-seven (27) patients were enrolled following first (59%) or second (41%) recurrence having previously failed surgery, radiation, and temozolomide (100%). The median longest tumor diameter was 40 mm (range 20-77 mm). Patients were randomized to DNX-2401 followed by IFN (n = 18) or to DNX-2401 alone (n = 9). Due to the poor tolerability of IFN, the median duration of treatment was only 6 weeks (range 0-30 weeks), and two patients did not initiate treatment as scheduled due to early clinical deterioration. The most frequent grade 3-4 AEs across treatment groups were fatigue, headache, and seizures consistent with pre-existing symptoms, underlying disease and/or surgery. Based upon a preliminary intent-to-treat analysis, IFN did not appear to provide additional benefit. However, OS-12 and OS-18 for all patients enrolled was 33% and 22%, respectively regardless of treatment assignment. Three patients remain alive at 19, 21, and 22 months (DNX-2401, n = 1; DNX-2401 + IFN, n = 2). Interestingly, 50% of patients with a baseline tumor diameter of ≤ 42 mm survived beyond 12 months, potentially identifying a sub-population of patients that may live longer following intratumoral DNX-2401. Conclusions: DNX-2401 was well tolerated as monotherapy. Although the addition of IFN did not improve survival, clinical activity following a single injection of DNX-2401 is encouraging and supports an ongoing Phase II study of DNX-2401 for recurrent glioblastoma. Clinical trial information: NCT02197169.

Immunological targeting of CD133 in recurrent glioblastoma: A multi-center phase I translational and clinical study of autologous CD133 dendritic cell immunotherapy

2059

Background: A hallmark of glioblastoma is the high incidence of tumor recurrence, thought to be triggered by cancer stem cells. These tumorigenic cells are resistant to irradiation and chemotherapeutic agents. The target antigen, CD-133, was chosen because it has been reported as a cancer stem cell antigen overexpressed in glioblastoma tumors and associated with shorter survival. Recent clinical trials suggest that the mean overall survival for these patients is roughly 5-9 months, emphasizing the important unmet medical need in this disease requiring additional strategic approaches. Dendritic cell immunotherapies such as ICT-121 could provide benefit to patients by educating their immune systems to induce the formation of cytotoxic T cells that attack tumor cells bearing the target antigen. In addition to immediate attack on tumor cells present at dosing, a long-term memory response effective against tumor recurrence might be induced. Immunotherapy, such as ICT-121, that targets cancer stem cells could be an important treatment for this disease. Methods: This Phase I multi-center trial of ICT-121 targeting CD133 was designed to assess safety and tolerability (primary endpoint) and to monitor overall survival and progression-free survival (secondary endpoints). ICT-121 is comprised of autologous dendritic cells that are loaded with two HLA-A2 restricted epitopes of the CD133 antigen. CD133 is overexpressed on glioblastoma cancer stem cells. The HLA-A2 patients that had undergone resection for recurrence of glioblastoma were treated with ICT-121 once a week for 4 weeks during the induction phase and then once every 2 months during the maintenance phase until disease progression, death, ICT-121 depletion or discontinuation. Results: A total of 20 patients were treated and eight of these patients are still alive. Immune response data with cytokine mRNA expression demonstrated a response to the CD133 epitopes. A total of 20 patients were treated and eight of these patients are still alive. Conclusions: The results from this Phase I trial suggest that ICT-121 is both safe and well-tolerated with an immune response seen in a subset of patients. Clinical trial information: NCT02049489.

Maintenance Therapy With Tumor-Treating Fields Plus Temozolomide vs Temozolomide Alone for Glioblastoma: A Randomized Clinical Trial

IMPORTANCE

Glioblastoma is the most devastating primary malignancy of the central nervous system in adults. Most patients die within 1 to 2 years of diagnosis. Tumor-treating fields (TTFields) are a locoregionally delivered antimitotic treatment that interferes with cell division and organelle assembly.

OBJECTIVE

To evaluate the efficacy and safety of TTFields used in combination with temozolomide maintenance treatment after chemoradiation therapy for patients with glioblastoma.

DESIGN, SETTING, AND PARTICIPANTS

After completion of chemoradiotherapy, patients with glioblastoma were randomized (2:1) to receive maintenance treatment with either TTFields plus temozolomide (n = 466) or temozolomide alone (n = 229) (median time from diagnosis to randomization, 3.8 months in both groups). The study enrolled 695 of the planned 700 patients between July 2009 and November 2014 at 83 centers in the United States, Canada, Europe, Israel, and South Korea. The trial was terminated based on the results of this planned interim analysis.

INTERVENTIONS

Treatment with TTFields was delivered continuously (>18 hours/day) via 4 transducer arrays placed on the shaved scalp and connected to a portable medical device. Temozolomide (150-200 mg/m2/d) was given for 5 days of each 28-day cycle.

MAIN OUTCOMES AND MEASURES

The primary end point was progression-free survival in the intent-to-treat population (significance threshold of .01) with overall survival in the per-protocol population (n = 280) as a powered secondary end point (significance threshold of .006). This prespecified interim analysis was to be conducted on the first 315 patients after at least 18 months of follow-up.

RESULTS

The interim analysis included 210 patients randomized to TTFields plus temozolomide and 105 randomized to temozolomide alone, and was conducted at a median follow-up of 38 months (range, 18-60 months). Median progression-free survival in the intent-to-treat population was 7.1 months (95% CI, 5.9-8.2 months) in the TTFields plus temozolomide group and 4.0 months (95% CI, 3.3-5.2 months) in the temozolomide alone group (hazard ratio [HR], 0.62 [98.7% CI, 0.43-0.89]; P = .001). Median overall survival in the per-protocol population was 20.5 months (95% CI, 16.7-25.0 months) in the TTFields plus temozolomide group (n = 196) and 15.6 months (95% CI, 13.3-19.1 months) in the temozolomide alone group (n = 84) (HR, 0.64 [99.4% CI, 0.42-0.98]; P = .004).

CONCLUSIONS AND RELEVANCE

In this interim analysis of 315 patients with glioblastoma who had completed standard chemoradiation therapy, adding TTFields to maintenance temozolomide chemotherapy significantly prolonged progression-free and overall survival.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00916409.

Two cilengitide regimens in combination with standard treatment for patients with newly diagnosed glioblastoma and unmethylated MGMT gene promoter: results of the open-label, controlled, randomized phase II CORE study

BACKGROUND

Survival outcomes for patients with glioblastoma remain poor, particularly for patients with unmethylated O(6)-methylguanine-DNA methyltransferase (MGMT) gene promoter. This phase II, randomized, open-label, multicenter trial investigated the efficacy and safety of 2 dose regimens of the selective integrin inhibitor cilengitide combined with standard chemoradiotherapy in patients with newly diagnosed glioblastoma and an unmethylated MGMT promoter.

METHODS

Overall, 265 patients were randomized (1:1:1) to standard cilengitide (2000 mg 2×/wk; n = 88), intensive cilengitide (2000 mg 5×/wk during wk 1-6, thereafter 2×/wk; n = 88), or a control arm (chemoradiotherapy alone; n = 89). Cilengitide was administered intravenously in combination with daily temozolomide (TMZ) and concomitant radiotherapy (RT; wk 1-6), followed by TMZ maintenance therapy (TMZ/RT→TMZ). The primary endpoint was overall survival; secondary endpoints included progression-free survival, pharmacokinetics, and safety and tolerability.

RESULTS

Median overall survival was 16.3 months in the standard cilengitide arm (hazard ratio [HR], 0.686; 95% CI: 0.484, 0.972; P = .032) and 14.5 months in the intensive cilengitide arm (HR, 0.858; 95% CI: 0.612, 1.204; P = .3771) versus 13.4 months in the control arm. Median progression-free survival assessed per independent review committee was 5.6 months (HR, 0.822; 95% CI: 0.595, 1.134) and 5.9 months (HR, 0.794; 95% CI: 0.575, 1.096) in the standard and intensive cilengitide arms, respectively, versus 4.1 months in the control arm. Cilengitide was well tolerated.

CONCLUSIONS

Standard and intensive cilengitide dose regimens were well tolerated in combination with TMZ/RT→TMZ. Inconsistent overall survival and progression-free survival outcomes and a limited sample size did not allow firm conclusions regarding clinical efficacy in this exploratory phase II study.

Benefit from procarbazine, lomustine, and vincristine in oligodendroglial tumors is associated with mutation of IDH

PURPOSE

Patients with 1p/19q codeleted anaplastic oligodendroglial tumors who participated in RTOG (Radiation Therapy Oncology Group) 9402 lived much longer after chemoradiotherapy (CRT) than radiation therapy (RT) alone. However, some patients with noncodeleted tumors also benefited from CRT; survival curves separated after the median had been reached, and significantly more patients lived ≥ 10 years after CRT than RT. Thus, 1p/19q status may not identify all responders to CRT.

PATIENTS AND METHODS

Using trial data, we inquired whether an IDH mutation or germ-line polymorphism associated with IDH-mutant gliomas identified the patients in RTOG 9402 who benefited from CRT.

RESULTS

IDH status was evaluable in 210 of 291 patients; 156 (74%) had mutations. rs55705857 was evaluable in 245 patients; 76 (31%) carried the G risk allele. Both were associated with longer progression-free survival after CRT, and mutant IDH was associated with longer overall survival (9.4 v 5.7 years; hazard ratio [HR], 0.59; 95% CI, 0.40 to 0.86; P = .006). For those with wild-type tumors, CRT did not prolong median survival (1.3 v 1.8 years; HR, 1.14; 95% CI, 0.63 to 2.04; P = .67) or 10-year survival rate (CRT, 6% v RT, 4%). Patients with codeleted mutated tumors (14.7 v 6.8 years; HR, 0.49; 95% CI, 0.28 to 0.85; P = .01) and noncodeleted mutated tumors (5.5 v 3.3 years; HR, 0.56; 95% CI, 0.32 to 0.99; P < .05) lived longer after CRT than RT.

CONCLUSION

IDH mutational status identified patients with oligodendroglial tumors who did (and did not) benefit from alkylating-agent chemotherapy with RT. Although patients with codeleted tumors lived longest, patients with noncodeleted IDH-mutated tumors also lived longer after CRT.

Chemotherapy plus radiotherapy (CT-RT) versus RT alone for patients with anaplastic oligodendroglioma: Long-term results of the RTOG 9402 phase III study

2008b

Background: Anaplastic oligodendrogliomas, pure (AO) and mixed (AOA), are chemosensitive tumors, especially if co-deleted for chromosomes 1p and 19q, but whether addition of CT to RT prolongs overall survival (OS), is unknown. Methods: In the RTOG 9402 Phase III trial, patients (pts) with AO/AOA were randomly assigned to PCV [procarbazine, CCNU (lomustine) and vincristine] followed by immediate RT vs. immediate RT alone. Early analysis showed no OS benefit for the PCV+RT group but combined therapy was associated with a longer progression-free survival (PFS). It also showed that the finding of 1p/19q co-deletion was associated with a longer OS independent of treatment. The current analysis has a median follow up of 11.3 years (yrs). Results: Two hundred ninety-one patients were randomized, 148 to PCV+RT and 143 to RT. PCV+RT was associated with longer PFS [2.5 vs. 1.7 yrs, hazard ratio (HR) 0.68, 95% confidence interval (CI) (0.53, 0.88), P = 0.003] and the 1p/19q co-deletion with a longer Median Survival Time (MST) [8.7 vs. 2.7 yrs, HR 0.41, 95% CI (0.30, 0.55), P < 0.001]. For the entire cohort, there was no difference in MST by treatment [4.6 yrs for PCV+RT vs. 4.7 yrs for RT, HR 0.79, 95% CI (0.60, 1.04), P = 0.1]. However, patients with 1p/19q co-deleted tumors lived much longer after PCV+RT (n = 59) than after RT (n = 67) [14.7 vs. 7.3 yrs, HR 0.59, 95% CI (0.37, 0.95), P = 0.03]. There was no difference in MST by treatment in pts without the 1p/19q co-deletion [n=137; 2.6 vs. 2.7 yrs, HR 0.85, 95% CI (0.58, 1.23), P = 0.39]. Re-operation rates upon progression were similar between treatment arms in co-deleted pts (43%, PCV+RT vs. 54%, RT) but salvage CT rates were higher in the RT arm [57% vs. 81% (P = 0.04)]. Conclusions: PCV followed by immediate RT was a highly effective therapy for patients with 1p/19q co-deleted AO/AOA. In this setting, 1p/19q co-deletion was both prognostic and predictive, and the early PFS benefit in co-deleted cases was a harbinger of their longer OS. [This work was supported by RTOG grants U10 CA21661 and U10 CA32115, NCCTG grant U10 CA25224, ECOG grants CA17145 and CA21115, SWOG grant CA32102, and CCOP grant U10 CA37422 from the National Cancer Institute (NCI)]

A randomized, double‑blind, controlled phase IIb study of the safety and efficacy of ICT‑107 in newly diagnosed patients with glioblastoma multiforme following resection and chemoradiation

TPS2107

Background: Tumor stem cells have been correlated with recurrence and clinical outcome in glioblastoma multiforme (GBM). ICT‑107 is an autologous vaccine consisting of the patient’s dendritic cells pulsed with 6 synthetic peptide CTL epitopes targeting the GBM tumor and tumor‑stem cell associated antigens MAGE‑1, HER‑2, AIM‑2, TRP‑2, gp100 and IL‑13Rα2. Phase I results showed a good safety profile and interesting clinical potential (ASCO, 2010, abs#2097 and ASCO, 2011, abs#2042) in 16 newly diagnosed GBM patients with a median progression-free survival (PFS) of 16.9 months (measured from surgery) and a median overall survival (OS) of 38.4 months. Methods: In this Phase II study eligible patients have newly diagnosed GBM and complete surgical resection or minimum residual tumor < 1 cm3, are HLA-A1 and/or HLA-A2 positive, older than 18, have Karnofsky Performance Score (KPS) of ≥ 70% and have adequate hematologic and chemistry parameters. Patients with a serious immune or autoimmune disorder or other systemic disease are excluded. Patients undergo apheresis to isolate peripheral blood mononuclear cells (PBMCs) to be used for preparation of study treatment (ICT‑107 and Control). Pre-study treatment consists of 6 weeks of concurrent temozolomide (TMZ) and radiation. After stratification by site and age, patients are randomized 2:1 to receive either ICT-107 or its matching control (autologous, unpulsed dendritic cells). Patients then receive induction ICT-107 or control once a week for four weeks. All patients subsequently receive maintenance TMZ for 5 days per month for 12 months. Booster vaccinations occur at Cycles 1, 3, 6 and 10, and every six months thereafter. The primary endpoint is OS and secondary endpoints include PFS, rates of OS and PFS at 6 months after surgery and every 3 months thereafter, safety and tolerability of ICT‑107, immune response to ICT-107 and predictors of response. 120 patients have been enrolled in this ongoing trial. It is expected that approximately 200 patients will be enrolled for screening with the intention to randomize at least 102 patients. The trial significance is alpha=0.025 one-sided.

Randomized Phase II Study of Cilengitide, an Integrin-Targeting Arginine-Glycine-Aspartic Acid Peptide, in Recurrent Glioblastoma Multiforme

Purpose

Cilengitide, an inhibitor of αvβ3 and αvβ5 integrin receptors, demonstrated minimal toxicity and durable activity across a wide range of doses administered to adults with recurrent glioblastoma multiforme (GBM) in a prior phase I study. The current multicenter phase II study was conducted to evaluate the activity and safety of cilengitide in GBM patients at first recurrence.

Patients and Methods

Eligible patients were randomly assigned to receive either 500 or 2,000 mg of cilengitide twice weekly on a continuous basis. Patients were assessed every 4 weeks. The primary end point was 6-month progression-free survival (PFS) rate. Secondary end points included PFS, overall survival (OS), and radiographic response, as well as quality-of-life and pharmacokinetic assessments.

Results

Eighty-one patients were enrolled, including 41 on the 500-mg arm and 40 on the 2,000-mg arm. The safety profile of cilengitide was excellent, with no significant reproducible toxicities observed on either arm. Antitumor activity was observed in both treatment cohorts but trended more favorably among patients treated with 2,000 mg, including a 6-month PFS of 15% and a median OS of 9.9 months.

Conclusion

Cilengitide monotherapy is well tolerated and exhibits modest antitumor activity among recurrent GBM patients. Additional studies integrating cilengitide into combinatorial regimens for GBM are warranted.

Phase I study of temozolomide and irinotecan for recurrent malignant gliomas in patients receiving enzyme-inducing antiepileptic drugs: a north american brain tumor consortium study

PURPOSE

To determine the maximum tolerated dose of irinotecan when administrated with temozolomide every 28 days, in patients with recurrent malignant glioma who were also receiving CYP450 enzyme-inducing antiepileptic drugs (EIAED), and to characterize the pharmacokinetics of irinotecan and its metabolites. The study was also intended to assess whether temozolomide affects the conversion of irinotecan to SN-38.

DESIGN

Patients with recurrent malignant glioma received a fixed dose of temozolomide (150 mg/m(2)) daily for 5 days from days 1 to 5 every 28 days, and an i.v. infusion of irinotecan on days 1 and 15 of each cycle. The starting dose of irinotecan was 350 mg/m(2), which was escalated to 550 mg/m(2) in 50-mg/m(2) increments. The plasma pharmacokinetics of irinotecan and its active metabolite, SN-38, were determined during the infusion of irinotecan on cycle 1, day 1.

RESULTS

Thirty-three patients were enrolled into the study and treated. Thirty-one patients were evaluable for both tumor response and toxicity and two patients were evaluable for toxicity only. Common toxicities included neutropenia and thrombocytopenia, nausea, vomiting, and diarrhea. Dose-limiting toxicities were grade 3 diarrhea and nausea/vomiting. The maximum tolerated dose for irinotecan was determined to be 500 mg/m(2).

CONCLUSIONS

The recommended phase II dose of irinotecan in combination with temozolomide for patients receiving EIAEDs is 500 mg/m(2), administrated every 15 days on a 28-day schedule. This study also confirmed that concomitant administration of EIAEDs increases irinotecan clearance and influences SN-38 disposition. No pharmacokinetic interaction was observed between temozolomide and irinotecan.

Progression-free survival: an important end point in evaluating therapy for recurrent high-grade gliomas

The North American Brain Tumor Consortium (NABTC) uses 6-month progression-free survival (6moPFS) as the efficacy end point of therapy trials for adult patients with recurrent high-grade gliomas. In this study, we investigated whether progression status at 6 months predicts survival from that time, implying the potential for prolonged survival if progression could be delayed. We also evaluated earlier time points to determine whether the time of progression assessment alters the strength of the prediction. Data were from 596 patient enrollments (159 with grade III gliomas and 437 with grade IV tumors) in NABTC phase II protocols between February 1998 and December 2002. Outcome was assessed statistically using Kaplan-Meier curves and Cox proportional hazards models. Median survivals were 39 and 30 weeks for patients with grade III and grade IV tumors, respectively. Twenty-eight percent of patients with grade III and 16% of patients with grade IV tumors had progression-free survival of >26 weeks. Progression status at 9, 18, and 26 weeks predicted survival from those times for patients with grade III or grade IV tumors (p < 0.001 and hazard ratios < 0.5 in all cases). Including KPS, age, number of prior chemotherapies, and response in a multivariate model did not substantively change the results. Progression status at 6 months is a strong predictor of survival, and 6moPFS is a valid end point for trials of therapy for recurrent malignant glioma. Earlier assessments of progression status also predicted survival and may be incorporated in the design of future clinical trials.

Pharmacokinetic and tumor distribution characteristics of temsirolimus in patients with recurrent malignant glioma

PURPOSE

To characterize the pharmacokinetics of temsirolimus and its major metabolite, sirolimus, in patients receiving enzyme-inducing antiepileptic drugs (EIAED) compared with patients receiving non-EIAEDs. An additional objective was to determine whether concentrations of temsirolimus or sirolimus were achieved in brain tumor tissue.

EXPERIMENTAL DESIGN

Patients with recurrent malignant gliomas not receiving EIAEDs initially received temsirolimus weekly at a dose of 250 mg i.v. The dose was subsequently reduced to 170 mg due to intolerable side effects. For patients taking EIAEDs, the starting dose of temsirolimus was 250 mg with standard dose escalation until the maximal tolerated dose was established. Ten whole blood samples were obtained over a period of 24 h after administration of temsirolimus for pharmacokinetic assessments. Patients eligible for cytoreductive surgery received temsirolimus before tumor resection. Whole blood and tumor tissue were obtained for analysis.

RESULTS

Significant differences in the pharmacokinetic variables for temsirolimus and sirolimus were observed between the two patient groups at a comparable dose level of 250 mg. For patients receiving EIAEDs, the systemic exposure to temsirolimus was lower by 1.5-fold. Likewise, peak concentrations and exposure to sirolimus were lower by 2-fold. Measurable concentrations of temsirolimus and sirolimus were observed in brain tumor specimens. The average tissue to whole blood ratio for temsirolimus was 1.43 and 0.84 for sirolimus.

CONCLUSIONS

Drugs that induce cytochrome P450 3A4, such as EIAEDs, significantly affect the pharmacokinetics of temsirolimus and its active metabolite, sirolimus. Total exposure to temsirolimus and sirolimus was lower in the EIAED group at the maximum tolerated dose of 250 mg compared with the non-EIAED group at the maximum tolerated dose of 170 mg. However, brain tumor tissue concentrations of temsirolimus and sirolimus were relatively comparable in both groups of patients at their respective dose levels. Correlative analyses of the tissue for the inhibition of the key regulators (p70S6 kinase and 4E-binding protein 1) of mammalian target of rapamycin are necessary to define the therapeutic significance of the altered exposure to temsirolimus.

Phase II Trial of Tipifarnib in Patients With Recurrent Malignant Glioma Either Receiving or Not Receiving Enzyme-Inducing Antiepileptic Drugs: A North American Brain Tumor Consortium Study

Purpose

A phase II study was undertaken in patients with recurrent malignant glioma to determine the efficacy and safety of tipifarnib, a farnesyltransferase inhibitor, dosed at the respective maximum-tolerated dose (MTD) for patients receiving and not receiving enzyme-inducing antiepileptic drugs (EIAEDs). Because tipifarnib undergoes extensive hepatic metabolism, MTD is doubled in patients on EIAEDs. The population included 67 patients with glioblastoma multiforme (GBM) and an exploratory group of 22 patients with anaplastic glioma (AG).

Patients and Methods

Patients received tipifarnib (300 and 600 mg bid for 21 days every 4 weeks in non-EIAED and EIAED patients, respectively). All patients were assessable for efficacy and safety.

Results

Two AG patients (9.1%) and eight GBM patients (11.9%) had progression-free survival (PFS) more than 6 months. Among the latter eight GBM patients, six of 36 patients (16.7%; 95% CI, 7% to 32%) were not receiving EIAEDs and two of 31 patients (6.5%; 95% CI, 1% to 20%) were receiving EIAEDs. Four patients had partial responses in group A GBM and one patient had a partial response group B GBM. An exploratory comparison of PFS between GBM groups A and B was statistically significant (P = .01). Patients not receiving EIAEDs had a higher incidence and increased severity of hematologic events. However, the incidence and severity of rash (the previously determined dose-limiting toxicity in patients receiving EIAEDs) seemed similar in EIAED and non-EIAED subgroups.

Conclusion

Tipifarnib (300 mg bid for 21 days every 4 weeks) shows modest evidence of activity in patients with recurrent GBM who are not receiving EIAEDs and is generally well tolerated in this population.

O6-benzylguanine suppression of O6-alkylguanine-DNA alkyltransferase in anaplastic gliomas

The purpose of the study was to determine the dose of O(6)-benzylguanine (BG) that would suppress O(6)-alkylguanine-DNA alkyltransferase (AGT) activity to undetectable levels in > 90% of anaplastic gliomas, as measured 6 h after a 1-h BG infusion. Subjects who were scheduled for surgical resection of a known or presumed anaplastic glioma received a 1-h infusion of BG. Tumor tissue was surgically removed approximately 6 h after the end of the infusion and was analyzed for AGT activity. The BG dose was escalated until at least 11 of 14 subjects had no detectable AGT activity. An additional cohort of patients received the identified effective dose of BG approximately 18 h before tumor resection in order to compare our results with an earlier study using the longer time interval. In the 79 subjects who were enrolled, there was no significant toxicity that was attributed to the BG. A dose-response relationship was determined between the BG dose and the percentage of subjects with undetectable AGT. A dose of 120 mg/m(2) suppressed AGT to less than detectable levels in 17 of 18 patients when the drug-resection interval was 6 h. With an 18-h interval, only 5 of 11 subjects had undetectable AGT at the 120-mg/m(2) dose. We conclude that a BG dose of 120 mg/m(2) given 6 h before an alkylating drug would be effective in suppressing AGT and possibly potentiating the cytotoxic effects of the drug.

Phase 1 trial of irinotecan (CPT-11) in patients with recurrent malignant glioma: a North American Brain Tumor Consortium study

This study was conducted to determine the maximum tolerated dose and dose-limiting toxicity of irinotecan (CPT-11) administered every 3 weeks to adults with progressive malignant glioma who were treated with enzyme inducing antiepileptic drug (EIAED) therapy, and to compare the pharmacokinetics with those in patients not on EIAED therapy treated at the recommended phase 2 dose for other cancers. The CPT-11 dose was 350 mg/m(2) i.v. every 3 weeks and remained fixed in patients not on EIAED therapy, but the dose was escalated by 50-mg/m(2) increments in patients on EIAED therapy. CPT-11 and its metabolites SN-38, SN-38 glucuronide (SN-38G), and APC (7-ethyl-10[4-N-(5 aminopentanoic acid)-1-piperidine]-carbonyloxycamptothecin) were characterized in both groups. Patients on EIAEDs received 350 to 800 mg/m(2) of CPT-11. Dose-limiting toxicity was due to grade 3 diarrhea despite maximal doses of loperamide. The systemic levels of CPT-11, APC, SN-38G, and SN-38 were all lower in the EIAED group. There was a moderate-to-fair relationship between CPT-11 dose and the area under the curve (AUC) for CPT-11 and APC over the 2, but no relationship dosage range of 350 to 800 mg/m between CPT-11 dose and the AUC for SN-38 or SN-38G. At the 750-mg/m(2) dose, the AUC for CPT-11 (21.6 microg x h/ml) matched the AUC (21.6 microg x h/ml) in the non-EIAED group treated with 350 mg/m(2) of CPT-11. We conclude that the recommended phase 2 dose of CPT-11 for patients on EIAEDs is 750 mg/m(2) when given every 3 weeks. A phase 2 study of patients with recurrent malignant glioma is ongoing to assess the efficacy of CPT-11 when the dose is stratified according to the use of EIAEDs.

Phase II study of neoadjuvant 1, 3-bis (2-chloroethyl)-1-nitrosourea and temozolomide for newly diagnosed anaplastic glioma

BACKGROUND

Temozolomide (TMZ) and 1, 3-bis (2-chloroethyl)-1-nitrosourea (BCNU) are reported to be active agents in anaplastic glioma (AG). TMZ has also been shown to deplete alkyltransferase, a DNA repair enzyme that contributes to nitrosourea resistance. The objective of the current study was to determine the efficacy and toxicity profile of a combination of these agents before radiotherapy in newly diagnosed AG.

METHODS

Eligibility criteria included histologically confirmed newly diagnosed AG with measurable enhancing disease, a Karnofsky performance score (KPS) > or = 60, normal pulmonary function, and normal laboratory parameters. In addition, informed consent was obtained from all patients. BCNU given at a dose of 150 mg/m(2) intravenously was followed after 2 hours by TMZ given at a dose of 550 mg/m(2) orally on Day 1 of a 42-day cycle to a maximum of 4 cycles, unless there was tumor progression or unacceptable toxicity.

RESULTS

Forty-one eligible patients were accrued. Their median age was 40 years. Seventy-six percent of patients had a KPS of 90-100. The histology was 81% anaplastic astrocytoma, 12% anaplastic oligodendroglioma, and 7% mixed tumors. Twenty-two percent of patients did not complete 4 cycles because of toxicity, mainly hematologic. Forty-six percent of patients experienced Grade 3 or 4 (according to National Cancer Institute Common Toxicity Criteria) thrombocytopenia. Twenty percent had Grade 4 granulocytopenia. Two patients died while receiving therapy, 1 of progressive disease and the other of Pneumocystis carinii pneumonia. The complete and partial response rates were 2% and 27% respectively. An additional 54% of patients had stable disease. Seventeen percent developed progressive disease (10% after the first cycle and 7% after the second cycle).

CONCLUSIONS

This neoadjuvant strategy was associated with significant myelosuppression and a modest response rate in patients with newly diagnosed AG.

Phase 2 study of BCNU and temozolomide for recurrent glioblastoma multiforme: North American Brain Tumor Consortium study

The purpose of this study was to evaluate the activity, measured in terms of progression-free survival (PFS) and response rates, of 1,3-bis(chloro-ethyl)-1-nitrosourea (BCNU) plus temozolomide in adult patients with recurrent glioblastoma multiforme. The phase 2 dose and schedule for this trial was BCNU 150 mg/m(2) i.v. followed in 2 h by temozolomide 550 mg/m(2) as a single oral dose. Treatment was repeated every 6 weeks for up to 8 cycles unless tumor progression was documented. The primary end point was PFS at 6 months (PFS-6). Response was a secondary end point, measured by MR imaging, neurological status, and steroid requirements prior to each 6-week cycle. The median age of eligible patients was 53, and 89.5% had no prior chemotherapy. All patients were evaluable for toxicity and time to progression. The PFS-6 was 21%. Overall survival was 68% at 6 months and 26% at 1 year. The MRI response for 36 patients was 2 partial responses, 2 minor responses, 19 cases of stable disease, and 13 immediate progressions. Median survival was 34 weeks, and median PFS was 11 weeks. Toxicity was primarily myelosuppression; no toxic deaths occurred. Historical phase 2 study data in this patient population show a PFS-6 of 15%. Recent data for use of temozolomide alone have shown a PFS-6 of 21%. We conclude that BCNU plus temozolomide when used in these doses and schedule has only modest activity, with significant toxicity, and appears to be no more effective than single-agent temozolomide.

A phase I trial of 1,3-bis(2-chloroethyl)-1-nitrosourea plus temozolomide: a North American Brain Tumor Consortium study

The North American Brain Tumor Consortium conducted a phase I trial of the combination 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and temozolomide. Eligibility included a patient with a cancer type that was considered refractory to standard therapy. Prior nitrosourea treatments were not permitted. There were parallel dose escalations in two treatment schedules. Forty-five patients were enrolled during an 18-month period. The maximum tolerated doses (MTDs) when temozolomide followed BCNU (Arm A) were temozolomide at 550 mg/m2/p.o. and BCNU at 150 mg/m2/i.v.), whereas the MTD when temozolomide preceded BCNU (Arm B) was temozolomide at 400 mg/m2/p.o. and BCNU at 100 mg/m2/i.v. Toxicity was predominantly hematologic, although there were three instances of pulmonary toxicity, which in one case could have represented potentiation of nitrosourea-induced pulmonary fibrosis. The half-life of temozolomide was 1.86 (+/-0.31) h. There was a moderate relationship between dose and peak concentration and a strong relationship between dose and plasma concentration time curve. Pharmacokinetic parameters of temozolomide were unaffected by the treatment schedule, so the difference in MTD between the schedules is likely due to a biologic rather than a pharmacokinetic sequence interaction. There were 9 partial responses among 43 patients evaluable for response, including 5 of 25 with a histologic diagnosis of glioblastoma. The recommended dose and schedule for phase II trials of this regimen are BCNU 150 mg/m2/i.v. followed in 2 h by temozolomide 550 mg/m2/p.o. repeated every 6 weeks. We are also recommending screening and periodic pulmonary function testing during treatment to assess the possible potentiation of nitrosourea-induced pulmonary fibrosis.

Infrequency of p53 gene mutations in ependymomas

Ependymomas, which comprise 5% of central nervous system tumors, have not been extensively characterized genetically. The p53 tumor suppressor gene is frequently mutated in human cancer, and is important in the pathogenesis of other central nervous system (CNS) tumors. Chromosomal DNA corresponding to the p53 tumor suppressor gene was amplified by the polymerase chain reaction (PCR) from 31 archival ependymoma specimens. DNA was screened for the presence of p53 mutations by single strand conformational polymorphism (SSCP) analysis; samples with altered mobility were further tested for the presence of mutation by direct DNA sequence analysis. Of the 31 ependymomas tested, one contained a detectable DNA sequence change in the p53 gene. Sequencing revealed a silent mutation in exon 6, at codon 213, which represents a known p53 sequence polymorphism. These finding suggest that in contrast to many other human cancers, p53 mutation is not important in the pathogenesis or progression of ependymomas.

Rapid regulation of c-myc protooncogene expression by progesterone in the avian oviduct

The mRNA levels of genes known to be regulated by sex steroids are not altered until 1 hr or longer after steroid treatment, although the steroid receptor complexes are bound to nuclear acceptor sites within 5 min. In a search for early regulation of gene transcription, total chick oviduct RNA was isolated at various times after injection (i.p.) of progesterone and analyzed for c-myc expression. Levels of c-myc mRNA began to decrease in response to progesterone by 10 min after injection. The mRNA levels continued to decrease, reached a 70% reduction at 30 min, and returned to control values by 8 hr after steroid injection. Changes in alpha-tubulin mRNA levels were markedly less in these same RNA preparations. The effect was dependent on the dose of the steroid and was target-tissue specific. These changes occurred much more rapidly than changes in egg-white protein mRNA levels. Vehicle alone did not alter c-myc mRNA levels. Early regulated genes such as c-myc may represent the initial site of action of steroid receptors in the genome.

Modulation of canine myocardial sarcolemmal membrane fluidity by amphiphilic compounds

Amphiphilic moieties such as lysophosphoglycerides and long-chain acyl carnitines accumulate in ischemic myocardium and potentially contribute to the sequelae of myocardial ischemia. To characterize alterations in membrane molecular dynamics produced by amphiphilic compounds, highly purified preparations of canine myocardial sarcolemma were spin-labeled with paramagnetic probes (5-, 12-, or 16-doxyl stearate), and alterations produced by amphiphilic compounds were quantified by electron spin resonance spectroscopy. Incorporation of 1.5, 3, or 6 mol % palmitoyl lysophosphatidylcholine resulted in a decrease of the order parameter of 16-doxyl stearate from 0.164 to 0.161, 0.155, and 0.145, respectively. Similar increases in membrane fluidity in the interior of the bilayer were present when palmitoyl lysophosphatidylethanolamine, L-palmitoyl carnitine, and platelet-activating factor were incorporated into sarcolemma. In contrast, incubation of sarcolemma with lysophosphatidylcholine did not result in significant change of the order parameter of 5-doxyl stearate, even at 6 mol %, demonstrating that lysophosphatidylcholine increases the transmembrane fluidity gradient. Sarcolemma treated with phospholipase A2 exhibited a time-dependent decrease in the rotational correlation time and order parameter when lysophospholipids constituted a small amount (6%) of sarcolemmal phospholipids. Furthermore, the effects of lysophosphatidylcholine were not dependent upon its physical state, since bilayers composed of gramicidin and lysophosphatidylcholine resulted in similar increases in membrane fluidity as micellar lysophosphatidylcholine. The results suggest that alterations in sarcolemmal molecular dynamics are one mechanism through which amphiphilic moieties mediate their multiple effects. Such alterations could contribute to the electrophysiological and biochemical sequelae of myocardial ischemia.