Intravenous carboplatin for recurrent gliomas. A dose-escalating phase II trial

Advances in Focused Ultrasound for the Treatment of Brain Tumors

Employing the full arsenal of therapeutics to treat brain tumors is limited by the relative impermeability of the blood-brain and blood-tumor barriers. In physiologic states, the blood-brain barrier serves a protective role by passively and actively excluding neurotoxic compounds; however, this functionality limits the penetrance of therapeutics into the tumor microenvironment. Focused ultrasound technology provides a method for overcoming the blood-brain and blood-tumor barriers through ultrasound frequency to transiently permeabilize or disrupt these barriers. Concomitant delivery of therapeutics has allowed for previously impermeable agents to reach the tumor microenvironment. This review details the advances in focused ultrasound in both preclinical models and clinical studies, with a focus on its safety profile. We then turn towards future directions in focused ultrasound-mediated therapies for brain tumors.

Medical Device Advances in the Treatment of Glioblastoma

Despite decades of research and the growing emergence of new treatment modalities, Glioblastoma (GBM) frustratingly remains an incurable brain cancer with largely stagnant 5-year survival outcomes of around 5%. Historically, a significant challenge has been the effective delivery of anti-cancer treatment. This review aims to summarize key innovations in the field of medical devices, developed either to improve the delivery of existing treatments, for example that of chemo-radiotherapy, or provide novel treatments using devices, such as sonodynamic therapy, thermotherapy and electric field therapy. It will highlight current as well as emerging device technologies, non-invasive versus invasive approaches, and by doing so provide a detailed summary of evidence from clinical studies and trials undertaken to date. Potential limitations and current challenges are discussed whilst also highlighting the exciting potential of this developing field. It is hoped that this review will serve as a useful primer for clinicians, scientists, and engineers in the field, united by a shared goal to translate medical device innovations to help improve treatment outcomes for patients with this devastating disease.

Convection-enhanced delivery for high-grade glioma

Glioblastoma (GBM) is the most common adult primary malignant brain tumor and is associated with a dire prognosis. Despite multi-modality therapies of surgery, radiation, and chemotherapy, its 5-year survival rate is 6.8%. The presence of the blood-brain barrier (BBB) is one factor that has made GBM difficult to treat. Convection-enhanced delivery (CED) is a modality that bypasses the BBB, which allows the intracranial delivery of therapies that would not otherwise cross the BBB and avoids systemic toxicities. This review will summarize prior and ongoing studies and highlights practical considerations related to clinical care to aid providers caring for a high-grade glioma patient being treated with CED. Although not the main scope of this paper, this review also touches upon relevant technical considerations of using CED, an area still under much development.

Phase I trial of intracerebral convection-enhanced delivery of carboplatin for treatment of recurrent high-grade gliomas

Background

Carboplatin is a potent cytoreductive agent for a variety of solid tumors. However, when delivered systemically, clinical efficacy for the treatment of high grade gliomas is poor due to limited penetration across the blood-brain barrier (BBB). Direct intracerebral (IC) convection-enhanced delivery (CED) of carboplatin has been used to bypass the BBB and successfully treat the F98 rat glioma. Based on these studies, we initiated a Phase I clinical trial.

Objective

This Phase I clinical trial was conducted to establish the maximum tolerated dose and define the toxicity profile of carboplatin delivered intracerebrally via convection enhanced delivery (CED) for patients with high grade glial neoplasms.

Methods

Cohorts of 3 patients with recurrent WHO grade III or IV gliomas were treated with escalating doses of CED carboplatin (1–4 μg in 54mL over 72 hours) delivered via catheters placed at the time of recurrent tumor resection. The primary outcome measure was determination of the maximum tolerated dose (MTD). Secondary outcome measures included overall survival (OS), progression-free survival (PFS), and radiographic correlation.

Results

A total of 10 patients have completed treatment with infusion doses of carboplatin of 1μg, 2μg, and 4μg. The total planned volume of infusion was 54mL for each patient. All patients had previously received surgery and chemoradiation. Histology at treatment include GBM (n = 9) and anaplastic oligodendroglioma (n = 1). Median KPS was 90 (range, 70 to 100) at time of treatment. Median PFS and OS were 2.1 and 9.6 months after completion of CED, respectively. A single adverse event possibly related to treatment was noted (generalized seizure).

Conclusions

IC CED of carboplatin as a potential therapy for recurrent malignant glioma is feasible and safe at doses up to 4μg in 54mL over 72 hours. Further studies are needed to determine the maximum tolerated dose and potential efficacy.

Temporary blood-brain barrier disruption by low intensity pulsed ultrasound increases carboplatin delivery and efficacy in preclinical models of glioblastoma

INTRODUCTION

Glioblastoma (GBM) is the most common and aggressive primary brain cancer in adults. Few cytotoxic chemotherapies have been shown to be effective against GBM, due in part to the presence of the blood-brain barrier (BBB), which reduces the penetration of chemotherapies from the blood to the brain. Ultrasound-induced BBB opening (US-BBB) has been shown to increase the penetration of multiple chemotherapeutic agents in the brain in animal models. In the current study, the anti-tumor activity of carboplatin chemotherapy with and without US-BBB was investigated in several GBM mouse models.

METHODS

First, the IC50 of two commercial (U87 and U251) and six patient-derived GBM cell lines (PDCL) to carboplatin was measured. Next, U87 was subcutaneously grafted to a nude mouse model to test the in vivo response of the tumor to carboplatin in the absence of the BBB. Lastly, nude mice bearing orthotopically xenografted GBM cell lines (U87 or a PDCL) were randomized to four experimental groups: (i) untreated, (ii) US-BBB alone, (iii) carboplatin alone and, (iv) carboplatin + US-BBB. Mice were treated once weekly for 4 weeks and monitored for toxicity, tumor growth, and survival.

RESULTS

Carboplatin plus US-BBB enhanced survival (p = 0.03) and delayed tumor growth (p < 0.05) of GBM-bearing mice compared to carboplatin alone, with a 4.2-fold increase of carboplatin penetration in the brain, without evidence of significant neurological or systemic toxicity.

CONCLUSIONS

Carboplatin efficacy was enhanced in GBM mouse models with US-BBB and appears to be a promising chemotherapy for this approach.

Safety and Feasibility of Repeated and Transient Blood-Brain Barrier Disruption by Pulsed Ultrasound in Patients with Recurrent Glioblastoma

PURPOSE

The blood-brain barrier (BBB) limits the efficacy of drug therapies for glioblastoma (GBM). Preclinical data indicate that low-intensity pulsed ultrasound (LIPU) can transiently disrupt the BBB and increase intracerebral drug concentrations.

PATIENTS AND METHODS

A first-in-man, single-arm, single-center trial (NCT02253212) was initiated to investigate the transient disruption of the BBB in patients with recurrent GBM. Patients were implanted with a 1-MHz, 11.5-mm diameter cranial ultrasound device (SonoCloud-1, CarThera). The device was activated monthly to transiently disrupt the BBB before intravenous carboplatin chemotherapy.

RESULTS

Between 2014 and 2016, 21 patients were registered for the study and implanted with the SonoCloud-1; 19 patients received at least one sonication. In 65 ultrasound sessions, BBB disruption was visible on T1w MRI for 52 sonications. Treatment-related adverse events observed were transient and manageable: a transient edema at H1 and at D15. No carboplatin-related neurotoxicity was observed. Patients with no or poor BBB disruption (n = 8) visible on MRI had a median progression-free survival (PFS) of 2.73 months, and a median overall survival (OS) of 8.64 months. Patients with clear BBB disruption (n = 11) had a median PFS of 4.11 months, and a median OS of 12.94 months.

CONCLUSIONS

SonoCloud-1 treatments were well tolerated and may increase the effectiveness of systemic drug therapies, such as carboplatin, in the brain without inducing neurotoxicity.See related commentary by Sonabend and Stupp, p. 3750.

Blood-brain barrier, cytotoxic chemotherapies and glioblastoma

INTRODUCTION

Glioblastomas (GBM) are the most common and aggressive primary malignant brain tumors in adults. The blood brain barrier (BBB) is a major limitation reducing efficacy of anti-cancer drugs in the treatment of GBM patients. Areas covered: Virtually all GBM recur after the first-line treatment, at least partly, due to invasive tumor cells protected from chemotherapeutic agents by the intact BBB in the brain adjacent to tumor. The passage through the BBB, taken by antitumor drugs, is poorly and heterogeneously documented in the literature. In this review, we have focused our attention on: (i) the BBB, (ii) the passage of chemotherapeutic agents across the BBB and (iii) the strategies investigated to overcome this barrier. Expert commentary: A better preclinical knowledge of the crossing of the BBB by antitumor drugs will allow optimizing their clinical development, alone or combined with BBB bypassing strategies, towards an increased success rate of clinical trials.

Enhanced brain distribution of carboplatin in a primate model after blood-brain barrier disruption using an implantable ultrasound device

PURPOSE

Glioblastoma is both the most common and aggressive primary brain tumor in adults. Carboplatin chemotherapy has shown only modest efficacy in progressive high-grade gliomas. The limited clinical efficacy of carboplatin may be due to its low concentration in tissue when the drug is delivered intravenously. The aim of this study was to assess whether the tissue concentration of intravenously administered carboplatin could be enhanced by ultrasound-induced blood-brain disruption in a primate model.

METHODS

Carboplatin was administered intravenously for 60 min to a single primate following blood-brain barrier opening induced by an implantable ultrasound device. Blood and brain samples were collected after animal killing, which occurred 60 min after the end of carboplatin administration. Platinum quantification in ultrafiltrate plasma and brain samples was performed using inductively coupled plasma mass spectrometry.

RESULTS

The brain concentration of platinum was highly enhanced (5.2×) in the 3.9 cm(3) region sonicated by the US beam, with a higher concentration in more vascularized anatomical structures. At 5 and 10 mm from the US beam axis, platinum concentrations were slightly enhanced (2.2× and 1.3× respectively).

CONCLUSIONS

This study demonstrates that BBB opening using an implantable ultrasound transducer enhances the brain distribution of carboplatin in a loco-regional manner. Such a treatment approach is of significant interest for the treatment of primary brain tumors and is under current evaluation in a phase 1 clinical trial (NCT02253212).

Treating recurrent glioblastoma: an update

Glioblastoma, the most aggressive of the gliomas, has a high recurrence and mortality rate. The nature of this poor prognosis resides in the molecular heterogeneity and phenotypic features of this tumor. Despite research advances in understanding the molecular biology, it has been difficult to translate this knowledge into effective treatment. Nearly all will have tumor recurrence, yet to date very few therapies have established efficacy as salvage regimens. This challenge is further complicated by imaging confounders and to an even greater degree by the ever increasing molecular heterogeneity that is thought to be both sporadic and treatment-induced. The development of novel clinical trial designs to support the development and testing of novel treatment regimens and drug delivery strategies underscore the need for more precise techniques in imaging and better surrogate markers to help determine treatment response. This review summarizes recent approaches to treat patients with recurrent glioblastoma and considers future perspectives.

Repurposing existing agents as adjunct therapies for glioblastoma

Numerous non-oncologic medications have been found in the last decade to have anti-cancer properties. While the focus in oncology research should clearly remain on deriving new therapeutic strategies, repurposing these existing medications may offer the potential to rapidly enhance the effectiveness of treatment for resistant cancers. Glioblastoma, the most common and lethal brain cancer, is highly resistant to standard therapies and would benefit from even minor improvements in treatment. Numerous agents already in the clinic for non-cancer applications have been found to also possess potential against cancer or specifically against glioblastoma. These include agents with activities affecting oxidative stress, the immune reponse, epigenetic modifiers, cancer cell metabolism, and angiogenesis and invasiveness. This review serves as a guide for potential ways to repurpose individual drugs alongside standard glioblastoma therapies.

Evaluation of nanoparticle delivered cisplatin in beagles

Intracranial neoplasia is a significant cause of morbidity and mortality in both human and veterinary patients, and is difficult to treat with traditional therapeutic methods. Cisplatin is a platinum (Pt)-containing chemotherapeutic agent approved by the Food and Drug Administration; however, substantial limitations exist for its application in canine brain tumor treatment due to the difficulty in crossing the blood-brain barrier (BBB), development of resistance, and toxicity. A modified Pt(iv)-prodrug of cisplatin, Platin-M, was recently shown to be deliverable to the brain via a biocompatible mitochondria-targeted lipophilic polymeric nanoparticle (NP) that carries the drug across the BBB and to the mitochondria. NP mediated controlled release of Platin-M and subsequent reduction of this prodrug to cisplatin allowed cross-links to be formed with the mitochondrial DNA, which have no nucleotide excision repair system, forcing the overactive cancer cells to undergo apoptosis. Here, we report in vitro effects of targeted Platin-M NPs (T-Platin-M-NPs) in canine glioma and glioblastoma cell lines with results indicating that this targeted NP formulation is more effective than cisplatin. In both the cell lines, T-Platin-M-NP was significantly more efficacious compared to carboplatin, another Pt-based chemotherapy, which is used in the settings of recurrent high-grade glioblastoma. Mitochondrial stress analysis indicated that T-Platin-M-NP is more effective in disrupting the mitochondrial bioenergetics in both the cell types. A 14-day distribution study in healthy adult beagles using a single intravenous injection at 0.5 mg kg(-1) (with respect to Platin-M) of T-Platin-M-NPs showed high levels of Pt accumulation in the brain, with negligible amounts in the other analyzed organs. Safety studies in the beagles monitoring physical, hematological, and serum chemistry evaluations were within the normal limits on days 1, 7, and 14 after injection of either 0.5 mg kg(-1) or 2 mg kg(-1) or 2.2 mg kg(-1) (with respect to Platin-M) of T-Platin-M-NPs. At all doses over the 14-day period, no neurotoxicity was observed based upon periodic neurological examinations and cerebrospinal fluid analysis. These studies demonstrated the translational nature of T-Platin-M-NPs for applications in the treatment of brain tumors.

[Glioblastoma metastases: a literature review and a description of six clinical observations]

INTRODUCTION

since the 1990s, the literature has described cases of glioblastoma metastases with the development of foci located at a distance from the primary tumor. However, the pathogenesis of this process remains unclear until the end. This focus is believed to result, on the one hand, from tumor metastasis from the primary site and, on the other hand, from multifocal growth. This article presents a literature review and a description of clinical observations of patients with glioblastoma metastases.

MATERIAL AND METHODS

The study included 6 patients (1 female and 5 males) with brain glioblastomas who received treatment at the Burdenko Neurosurgical Institute (5 patients) and the Department of Neurosurgery of the Research Center of Neurology (1 patient) in the period from 2010 to 2014. Neurophysiological control was used if the tumor was localized near the eloquent cortical areas and pathways; 4 of 6 patients were operated on using the methods of intraoperative fluorescence diagnosis (5-ALA agent--Alasens).

RESULTS

Four patients had metastases within one hemisphere, two had metastases in the contralateral hemisphere in the period of 5 to 18 months after the first operation. The primary tumor site was located near the ventricular system in two patients. In one patient, the lateral ventricle was opened during the first operation. In another patient, the prepontine cistern was opened during the first operation. In two patients, the primary tumor site was located at a distance from the lateral ventricles, however, the tumor was located near them during recurrence. Based on metabolic navigation, fluorescence of the tumor was observed in the four patients during both the first and repeated operations.

CONCLUSIONS

The close relationship between primary glioblastomas and metastases and the cerebrospinal fluid circulation pathways may confirm the fact of dissemination of tumor cells with cerebrospinal fluid flow. In our opinion, there should be an increased suspicion of the possibility for metastases of glioblastomas that are closely associated with the cerebrospinal fluid circulation pathways. Metabolic navigation with 5-ALA is effective both during primary surgery in patients with glioblastomas and during resection of glioblastoma metastases.

The Role of Chemotherapy in the Treatment of Malignant Astrocytomas

Malignant astrocytomas are aggressive neoplasms with a dismal prognosis despite optimal treatment. Maximal resective surgery is traditionally complemented by radiation therapy. Chemotherapy is now used on patients as initial therapy when their functional status is congruent with further treatment. The classic agents used are nitrosoureas, but temozolomide has taken the front seat recently, with recent data demonstrating increased survival when this agent is used concurrently with radiation therapy in newly diagnosed glioblastoma patients. A new class of agents, refered to as biological modifiers, are increasingly used in clinical trials in an effort to affect the intrinsic biologic aberrations harboured by tumor cells. These drugs comprise differentiation agents, anti-angiogenic agents, matrix-metalloproteinase inhibitors and signal transduction inhibitors, among others. This article reviews the standard cytotoxic agents that have been used to treat malignant astrocytomas, and the different combination regimens offering promise. In addition, recent advances with biological modifiers are also discussed.

Platinum-based chemotherapy in recurrent high-grade glioma patients: retrospective study

Introduction:

To investigate the efficacy of platinum-based chemotherapy in patients with recurrent high-grade glioma (HGG) who had received previous alkylating line of chemotherapy.

Material and methods:

Case notes of patients who had received chemotherapy with carboplatin or cysplatin for recurrent HGG between June 2006 and July 2012 were reviewed. Baseline characteristics and outcomes after treatment were recorded.

Results:

Forty-eight patients received carboplatin/cysplatin as second line chemotherapy for recurrent HGG (grade III n=6; grade IV n=42). The median number of cycles completed was 4. Fifteen patients (28%) had at least minor response, 22 (49%) had stable disease and 11 (23%) had progressive disease. Six month progression-free survival was 30% (52% in patients with grade III glioma and 18% in patients with grade IV glioma). The median time to disease progression from the first treatment with platinum drug was 3.2 months. The median survival was 8 months (10 months for patients with grade III glioma and 7 months for patients with grade IV glioma). Among patients with either stable disease or a partial response, the median survival was 12 months compared with 3 months in patients with progressive disease. No survival or response rate differences were noted regarding the type of previous chemotherapy, nitrosoureas or temozolomide.

Conclusions:

Single-agent carboplatin/cysplatin has modest activity in patients with recurrent HGG previously treated with one line of chemotherapy, nitrosoureas or temozolomide. Despite the improvement of median survival of patients achieving stable disease or a partial response to treatment, more effective regimens are required for this patient population.

State of the art and perspectives in the treatment of glioblastoma

Glioblastoma is the most common malignant primary brain tumor. Cures are rare and median survival varies from several to 22 months. Standard treatment for good performance patients consists of maximal safe surgical resection followed by radiotherapy with concurrent temozolomide (TMZ) chemotherapy and six cycles of postradiotherapy TMZ. At recurrence, treatment options include repeat surgery (with or without Gliadel wafer placement), reirradiation or systemic therapy. Most patients with good performance status are treated with cytotoxic chemotherapy or targeted biologic therapy following or in lieu of repeat surgery. Cytotoxic chemotherapy options include nitrosoureas, rechallenge with TMZ, platins, phophoramides and topoisomerase inhibitors, although efficacy is limited. Despite the intense effort of developing biologic agents that target angiogenesis and growth and proliferative pathways, bevacizumab is the only agent that has shown efficacy in clinical trials. It was awarded accelerated approval in the USA after demonstrating an impressive radiographic response in two open-label, prospective Phase II studies. Two randomized, Phase III trials of upfront bevacizumab have completed and may demonstrate survival benefit; however, results are pending at this time. Given the limited treatment options at tumor recurrence, consideration for enrollment on a clinical trial is encouraged.

An evaluation of the safety and feasibility of convection-enhanced delivery of carboplatin into the white matter as a potential treatment for high-grade glioma

Glioblastoma multiforme (GBM) is the most common and most aggressive form of intrinsic brain tumour. Despite standard treatment involving surgical resection, chemotherapy and radiotherapy this disease remains incurable with the majority of tumours recurring adjacent to the resection cavity. Consequently there is a clear need to improve local tumour control. Convection-enhanced delivery (CED) is a practical technique for administering chemotherapeutics directly into peritumoural brain. In this study, we have tested the hypothesis that carboplatin would be an appropriate chemotherapeutic agent to administer by CED into peritumoural brain to treat GBM. Within this study we have evaluated the relationships between carboplatin concentration, duration of exposure and tumour cell kill in vitro using GBM cell lines and the relationship between carboplatin concentration and clinical and histological evidence of toxicity in vivo. In addition, we have used laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to evaluate the distribution properties of carboplatin following CED into rat brain and to determine the rate at which carboplatin is cleared from the brain. Finally, we have compared the distribution properties of carboplatin and the MRI contrast agent gadolinium-DTPA in pig brain. The results of these experiments confirm that carboplatin can be widely distributed by CED and that it remains in the brain for at least 24 h after infusion completion. Furthermore, carboplatin provokes a significant GBM cell kill at concentrations that are not toxic to normal brain. Finally, we provide evidence that gadolinium-DTPA coinfusion is a viable technique for visualising carboplatin distribution using T1-weighted MR imaging.

A phase I trial of carboplatin administered by convection-enhanced delivery to patients with recurrent/progressive glioblastoma multiforme

Glioblastoma multiforme (GBM) is the commonest primary malignant brain tumour in adults. Standard treatment comprises surgery, radiotherapy and chemotherapy; however this condition remains incurable as these tumours are highly invasive and involve critical areas of the brain making it impossible to remove them surgically or cure them with radiotherapy. In the majority of cases the tumour recurs within 2 to 3 cm of the original site of tumour resection. Furthermore, the blood-brain barrier profoundly limits the access of many systemically administered chemotherapeutics to the tumour. Convection-enhanced delivery (CED) is a promising technique of direct intracranial drug delivery involving the implantation of microcatheters into the brain. Carboplatin represents an ideal chemotherapy to administer using this technique as glioblastoma cells are highly sensitive to carboplatin in vitro at concentrations that are not toxic to normal brain in vivo. This protocol describes a single-centre phase I dose-escalation study of carboplatin administered by CED to patients with recurrent or progressive GBM despite full standard treatment. This trial will incorporate 6 cohorts of 3 patients each. Cohorts will be treated in a sequential manner with increasing doses of carboplatin, subject to dose-limiting toxicity not being observed. This protocol should facilitate the identification of the maximum-tolerated infused concentration of carboplatin by CED into the supratentorial brain. This should facilitate the safe application of this technique in a phase II trial, treating patients with GBM, as well as for the treatment of other forms of malignant brain tumours, including metastases.

Phase II study of carboplatin, irinotecan, and bevacizumab for bevacizumab naïve, recurrent glioblastoma

We evaluated the efficacy of carboplatin, irinotecan, and bevacizumab among bevacizumab-naïve, recurrent glioblastoma (GBM) patients in a phase 2, open-label, single arm trial. Forty eligible patients received carboplatin (area under the plasma curve [AUC] 4 mg/ml-min) on day one, while bevacizumab (10 mg/kg) and irinotecan (340 mg/m(2) for patients on CYP3A-enzyme-inducing anti-epileptics [EIAEDs] and 125 mg/m(2) for patients not on EIAEDs) were administered on days 1 and 14 of every 28-day cycle. Patients were evaluated after each of the first two cycles and then after every other cycle. Treatment continued until progressive disease, unacceptable toxicity, non-compliance, or voluntary withdrawal. The primary endpoint was progression-free survival at 6 months (PFS-6) and secondary endpoints included safety and median overall survival (OS). All patients had progression after standard therapy. The median age was 51 years. Sixteen patients (40%) had a KPS of 90-100, while 27 (68%) were at first progression. The median time from original diagnosis was 11.4 months. The PFS-6 rate was 46.5% (95% CI: 30.4, 61.0%) and the median OS was 8.3 months [95% confidence interval (CI): 5.9, and 10.7 months]. Grade 4 events were primarily hematologic and included neutropenia and thrombocytopenia in 20 and 10%, respectively. The most common grade 3 events were neutropenia, thrombocytopenia, fatigue, and infection in 25, 20, 13, and 10%, respectively. Eleven patients (28%) discontinued study therapy due to toxicity and 17 patients (43%) required dose modification. One patient died due to treatment-related intestinal perforation. The addition of carboplatin and irinotecan to bevacizumab significantly increases toxicity but does not improve anti-tumor activity to that achieved historically with single-agent bevacizumab among bevacizumab-naïve, recurrent GBM patients. (ClinicalTrials.gov number NCT00953121).

Phase 2 study of carboplatin, irinotecan, and bevacizumab for recurrent glioblastoma after progression on bevacizumab therapy

BACKGROUND

The efficacy of carboplatin, irinotecan, and bevacizumab among recurrent glioblastoma (GBM) patients after prior progression on bevacizumab therapy in a phase 2, open-label, single-arm trial was evaluated.

METHODS

Eligible patients received carboplatin (area under the plasma curve [AUC] 4 mg/ml-min) on day 1, whereas bevacizumab (10 mg/kg) and irinotecan (340 mg/m(2) for patients on CYP3A enzyme-inducing anti-epileptics [EIAEDs] and 125 mg/m(2) for patients not on EIAEDs) were administered on days 1 and 14 of every 28-day cycle. Patients were evaluated after each of the first 2 cycles and then after every other cycle. Treatment continued until progressive disease, unacceptable toxicity, noncompliance, or voluntary withdrawal. The primary end point was progression-free survival at 6 months (PFS-6), and secondary end points included safety and median overall survival (OS).

RESULTS

All patients had progression on at least 1 prior bevacizumab regimen and 56% enrolled after either second or third overall progression. The median OS was 5.8 months (95% confidence interval [CI], 4.0-7.0 months) and PFS-6 rate was 16% (95% CI, 5.0%-32.5%). The most common grade 3 or 4 events were hematologic and occurred in 29% of cycles. Nine patients (38%) required dose modification. There were no treatment-related deaths.

CONCLUSIONS

Carboplatin, irinotecan, and bevacizumab was associated with modest activity and adequate safety among recurrent GBM patients who progressed on bevacizumab previously.

Safety and efficacy of erlotinib in first-relapse glioblastoma: a phase II open-label study

Erlotinib, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, is active in glioblastoma. We evaluated erlotinib efficacy in patients with first-relapse glioblastoma and assessed whether response was related to EGFR amplification and/or concomitant use of enzyme-inducing antiepileptic drugs (EIAEDs) in a phase II open-label study of glioblastoma patients in first relapse. Patients took erlotinib daily until progression. Starting dose was 150 mg for patients not taking EIAEDs and 300 mg for patients taking EIAEDs. Tumors were radiographically assessed every 8 weeks. Response was evaluated by investigators and confirmed by an independent radiology facility (IRF). The primary efficacy outcome was the objective response (OR) rate, according to the modified WHO criteria. Enrollment (n = 48) was terminated after a planned interim analysis due to an insufficient number of responses. The IRF confirmed 1 complete and 2 partial responses (PRs), for an OR rate of 6.3% (95% confidence interval [CI]: 1.7-17.0). Investigators determined 1 complete response and 3 PRs, median response duration of 7.0 months, 6-month progression-free survival (PFS) of 20% (95% CI: 10.0-32.4), and median survival of 9.7 months (95% CI: 5.9-11.6). Outcomes were not related to EGFR amplification or EIAED status. Diarrhea and rash were the most common adverse events (AEs); 23% of patients experienced grade 3-4 drug-related AEs. Despite the limited number of responses, 6-month PFS and median survival reached or exceeded the previously reported values for patients undergoing chemotherapy for recurrent glioblastoma. EGFR amplification was not associated with erlotinib activity. Given the large CIs and nonrandomized nature of the study, results should be interpreted cautiously.

Growth inhibition and chemosensitization of exogenous nitric oxide released from NONOates in glioma cells in vitro

Object

Exogenous nitric oxide (NO) from NO donors has cytotoxic, chemosensitizing, and radiosensitizing effects, and increases vascular permeability and blood flow in tumors. Yet little is known about whether these cytotoxic and chemosensitizing effects can be observed in glioma cells at doses that alter tumor physiological characteristics in vivo and whether these effects are tumor selective.

Methods

The effect of NO released from proline NONOate, diethylamine NONOate, spermine NONOate, and sodium nitrite on cell proliferation, apoptosis, and chemosensitivity to carboplatin of cultured glioma cells was studied in C6, U87 glioma cells, human glioblastoma cells, and human astrocytes and fibroblasts.

Results

Although proline NONOate failed to induce cell death, the other NO donors induced growth arrest when present in high concentrations (10−2 M) in all cell lines. Chemosensitization was observed after concomitant incubation with spermine NONOate and carboplatin in C6 and human glioblastoma cells. There is strong evidence that cell death occurs primarily by necrosis and to a lesser degree by apoptosis. The NO doses, which altered tumor physiology in vivo, were not cytotoxic, indicating that NO alters vascular permeability and cell viability in vivo by different mechanisms.

Conclusions

The authors found that NO-generating agents at high concentrations are potent growth inhibitors and might also be useful as chemosensitizers in glioma cells. These data corroborate the theory that the use of NOgenerating agents may play a role in the multimodal treatment of malignant gliomas but that the NO release must be targeted more specifically to tumor cells to improve selectivity and efficacy.

Phase II study of carboplatin and erlotinib (Tarceva, OSI-774) in patients with recurrent glioblastoma

Targeting the epidermal growth factor receptor (EGFR) may be effective in a subset of glioblastoma patients. This phase II study assessed the clinical activity of erlotinib plus carboplatin and to determine molecular predictors of response. The primary endpoint was progression free survival (PFS). Patients with recurrent glioblastoma with no more than two prior relapses received carboplatin intravenously on day 1 of every 28-day cycle (target AUC of 6 mg x ml/min). Daily erlotinib at 150 mg/day was dose escalated to 200 mg/day, as tolerated. Clinical and MRI assessments were made every 4 and 8 weeks, respectively. Tumor tissue was evaluated for EGFR, AKT and phosphatase and tensin homolog (PTEN) status. One partial response (PR) was observed out of 43 assessable patients. Twenty patients (47%) had stable disease (SD) for an average of 12 weeks. Median PFS was 9 weeks. The 6-month PFS rate was 14%. Median overall survival (OS) was 30 weeks. This regimen was well tolerated with grade 3/4 toxicities of fatigue, leukopenia, thrombocytopenia and rash requiring dose reductions. A recursive partitioning analysis (RPA) predicted that patients with KPS >or=90 treated with more than 1 prior regimen had the highest OS. No correlation was observed between EGFR, Akt or PTEN expression and either PFS or OS. Carboplatin plus erlotinib is well tolerated but has modest activity in unselected patients. Future trials should be stratified based on optimal molecular or clinical characteristics.

Recurrent glioblastoma multiforme: advances in treatment and promising drug candidates

Recurrent glioblastoma multiforme is a lethal disease with currently available treatment options having a limited impact on outcome. In this article, current and novel therapeutic approaches in the treatment of recurrent glioblastoma multiforme, including chemotherapy, targeted molecular agents, virotherapy/gene therapy and immunotherapy and challenges in developing novel therapeutic agents for glioblastoma multiforme will be discussed.

Chemotherapy in the treatment of malignant gliomas

Malignant gliomas are one of the most difficult tumors to treat, with only modest advances being made in the past few decades. Surgery and radiation have had the greatest impact, increasing survival. Chemotherapy modestly increases survival. The use of chemotherapy in the treatment of malignant gliomas is the focus of this paper and the more commonly used agents at diagnosis and relapse are reviewed. Since most patients fail first-, second- and even third-line agents that are commercially available, some of the more relevant new biological compounds will also be discussed. As treatments for brain tumors evolve, it is likely that optimal therapies will come from combination therapies that incorporate target-specific and chemotherapeutic agents.

Selective opening of the blood-tumor barrier by a nitric oxide donor and long-term survival in rats with C6 gliomas

OBJECT

The response of brain tumors to systemic chemotherapy is limited by the blood-tumor barrier (BTB). Nitric oxide (NO) has been implicated in the regulation of vascular permeability and blood flow. The authors evaluated the effects of exogenous NO, which was released from a short-acting NO donor (Proli/NO), and those of NO metabolites on the capillary permeability of tumors and normal brain tissue by using quantitative autoradiography in a C6 glioma model in rats.

METHODS

The Proli/NO was infused at a wide dose range (10(-2) to 10(-12) M) either intravenously or into the internal carotid artery (ICA) and demonstrated substantial tumor-selective increases in blood-brain barrier (BBB) permeability in response to various-sized tracers ([14C]aminoisobutyric acid, [14C]sucrose, [14C]dextran). Internal carotid artery or intravenous administration of sodium nitrite had a comparable effect on BTB permeability. The NO effect on microvascular permeability could be obtained without causing hemodynamic side effects. The effect of NO on the efficacy of carboplatin chemotherapy was investigated in intracerebral C6 gliomas. Simultaneous intravenous infusions of Proli/NO (10(-6) M) and carboplatin (20 mg/kg) led to long-term survival in 40% of rats harboring intracerebral C6 gliomas compared with control animals receiving ICA or intravenous infusions of carboplatin, Proli/NO, or vehicle alone. No residual tumor was demonstrated on histological or magnetic resonance imaging studies performed in rats treated with Proli/NO and carboplatin, and no toxicity was observed.

CONCLUSIONS

This new approach demonstrated the in vivo efficacy and safety of NO and nitrite in enhancing the delivery of systemically delivered radiolabeled tracers and carboplatin into rat gliomas. The NO-induced tumor-selective BBB disruption and intravenous carboplatin chemotherapy may be more efficacious than current chemotherapy strategies against brain tumors.

Phase II trial of thalidomide and carmustine for patients with recurrent high-grade gliomas

PURPOSE

The use of thalidomide as an antiangiogenic agent has met with only limited success in the treatment of malignant gliomas. On the basis of preclinical data demonstrating synergistic antitumor activity when antiangiogenic agents are combined with cytotoxic agents, we explored the clinical activity of the combination of thalidomide and carmustine (BCNU) in patients with recurrent high-grade gliomas.

PATIENTS AND METHODS

Patients with a histologic diagnosis of high-grade glioma and radiographic evidence of tumor progression after standard surgery, radiation, and chemotherapy were eligible for the study. Patients received BCNU 200 mg/m2 on day 1 of every 6-week cycle, and 800 mg/d of thalidomide that was escalated to a maximal dose of 1,200 mg/d as tolerated.

RESULTS

A total of 40 patients (38 with glioblastomas, two with anaplastic gliomas) were accrued to the study. The combination of thalidomide and BCNU was well tolerated; mild myelosuppression and mild to moderate sedation were the most common side effects. The median progression-free survival (100 days) and the objective radiographic response rate (24%) for patients with glioblastoma compared favorably with data from historical controls.

CONCLUSION

This is one of the first clinical trials to evaluate the strategy of combining a putative antiangiogenic agent with a cytotoxic agent in patients with primary brain tumors. Our data demonstrate that thalidomide in combination with BCNU is well tolerated and has antitumor activity in patients with recurrent high-grade gliomas. Although the combination seems to be more active than either agent alone, such conclusions await confirmatory trials.

Pre-irradiation semi-intensive chemotherapy with carboplatin and cyclophosphamide in malignant glioma: a phase II study

We undertook a phase II trial in 17 patients with malignant glioma and large measurable disease to assess response rate and survival with pre-irradiation chemotherapy, using higher doses than standard, trying to improve the outcome. Patients characteristics were: male/female 10/7, age 49 (range 23-59), median Karnofsky index 90% (range 70-100), glioblastoma multiforme/anaplastic astrocytoma 14/3. Treatment consisted of 2 cycles of carboplatin 200 mg/m(2) days 1-3 (or AUC x 8, total dose) plus cyclophosphamide 1000 mg/m(2) days 1-3. One partial response (6.5%) and two stabilizations (13.5%) were observed after pre-irradiation chemotherapy. Twelve out of 15 patients (80%) progressed after chemotherapy. Median survival time was 7.6 months and the survival at 1 year was 33%. Main toxicity was hematologic in the first cycle: neutropenia grade 4 in 100%; thrombocytopenia grade 4 in 73% and grade 3 in 27%; anemia grade 3 in 7%; in the second cycle: neutropenia and thrombocytopenia grade 4 in 100% and anemia grade 3 in 50%). No toxic death was related to treatment. This regimen showed limited activity in malignant glioma with large residual disease after surgery or biopsy.

Phase II study of weekly dose-intensified cisplatin chemotherapy with oral etoposide in recurrent glioma

BACKGROUND

In most patients with recurrent glioma chemotherapy is the only remaining treatment option. In general results of chemotherapy in these patients are poor, and trials on new regimens are indicated. Because relatively good results have been achieved with combinations of platin compounds and etoposide, we investigated a dose-intensified cisplatin regimen with oral etoposide.

METHODS

Eligible patients, with recurrent glioma after surgery and radiation therapy were treated with two four week-cycles with cisplatin 70 mg/m2 on days 1, 8 and 15, combined with oral etoposide 50 mg daily on days 1-15. In responding or stabilized patients, treatment was continued with six four week-cycles of oral etoposide 50 mg/m2 on days 1-21. Toxicity was assessed using the NCI Common Toxicity Criteria, a 50% decrease in contrast enhancing area on MRI scan was considered a partial response. Time to progression was measured from the start of chemotherapy.

RESULTS

Sixteen patients were included, 11 were progressive during or immediately after the induction cycles. Two patients achieved a partial response with a time to progression of 42 and 58 weeks. Three patients were stable for 11, 14 and 15 weeks respectively. Toxicity was modest.

DISCUSSION

This dose-intensified cisplatin regimen did not result in a significant number of objective responses and even the number of 'stable disease' was small. Given the low response rate of this intensive treatment, we consider this intensive regimen inappropriate for these patients.