Placebo-controlled trial of safety and efficacy of intraoperative controlled delivery by biodegradable polymers of chemotherapy for recurrent gliomas. The Polymer-brain Tumor Treatment Group

Future directions in glioblastoma therapy

The standard of care for both newly diagnosed and recurrent glioblastoma (GBM) patients has changed significantly in the past 10 years. Surgery followed by radiation and concurrent and adjuvant temozolomide is now the well-established standard treatment for newly diagnosed GBM. More recently, bevacizumab has become a mainstay of treatment for recurrent GBM. However, despite these advances and significant improvements in patient outcomes, the management and treatment of GBM patients remains a challenging and frustrating endeavor. Difficulties in interpretation of imaging changes after initial treatment, as well as the effects of antiangiogenic agents like bevacizumab on MRI characteristics, can make even the determination of disease progression complicated in multiple situations. Although a high percentage of patients benefit from antiangiogenic therapy in terms of radiographic response and progression-free survival, the effects of bevacizumab on prolonging overall survival remain controversial. Furthermore, tumor progression after treatment with antiangiogenic agents carries a particularly poor prognosis and there is a general lack of effective therapies for this group of patients. These limitations in terms of standard treatments contrast with a relative wealth of new information regarding the molecular underpinnings of GBM. Data from several large-scale efforts to molecularly profile GBM tumors including The Cancer Genome Atlas (TCGA) project have helped define specific molecular subtypes of GBM with distinct biology and clinical outcomes. These findings are helping to refine our understanding of the molecular heterogeneity and pathogenesis of these tumors and provide a basis for the future development of rational and targeted therapies for specific tumor subtypes.

Recurrent high-grade glioma: a diagnostic and therapeutic challenge

The management of recurrent high-grade gliomas with conventional, as well as targeted, therapies is problematic owing to several confounding issues. First, the diagnosis of recurrence using MRI is not straightforward, making the assessment of images in daily routines, as well as in clinical trials, challenging. While chemotherapies with cytotoxic agents have demonstrated initial treatment response, most tumors recur quickly. Second, targeted therapy itself is confounded by the heterogeneous expression of drug targets and nonlinear signaling effects, with functional redundancy and sidestream feedback mechanisms resulting in treatment failure; however, several active agents have been identified, most notably, bevacizumab (an antibody that sequesters VEGF), cilengitide (an inhibitor of integrin αvβ3/5 signaling) and cediranib (an oral tyrosine kinase inhibitor targeting PDGF receptor, c-Kit and all VEGF receptor subtypes). All of these agents have undergone multiple clinical trials and have demonstrated benefits and progression-free survival prolongation in recurrent disease. Given these advances, it is likely that tailored therapies for tumors harboring specific signaling defects will become more efficient and successful in the management of glioblastoma.

Challenges in immunotherapy presented by the glioblastoma multiforme microenvironment

Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumor in adults. Despite intensive treatment, the prognosis for patients with GBM remains grim with a median survival of only 14.6 months. Immunotherapy has emerged as a promising approach for treating many cancers and affords the advantages of cellular-level specificity and the potential to generate durable immune surveillance. The complexity of the tumor microenvironment poses a significant challenge to the development of immunotherapy for GBM, as multiple signaling pathways, cytokines, and cell types are intricately coordinated to generate an immunosuppressive milieu. The development of new immunotherapy approaches frequently uncovers new mechanisms of tumor-mediated immunosuppression. In this review, we discuss many of the current approaches to immunotherapy and focus on the challenges presented by the tumor microenvironment.

Discovering neurosurgery: new frontiers

Over the centuries, discoveries of lands unknown, treasures lost and buried, and formulas to delineate physicochemical processes have led to advancements in our understanding of how the world is structured and governed. In science and medicine, discoveries are frequently made following deliberate periods of observation and experimentation to test hypotheses. However, in some instances, discoveries may arise either following a "eureka moment" that transcends rigorous scientific experimentation or following a serendipitous observation. In many instances, scientific discoveries will lead to new inventions that are aimed at improving the manner in which tasks or operations are performed. In this address, some of the key discoveries in science and medicine that have impacted significantly on the field of neurosurgery are described. Some of these include discoveries in neuroanatomy, anesthesiology, infectious diseases, antisepsis, and radiology. Discoveries in the field of molecular science, from the discovery of DNA to next-generation DNA sequencing, which have helped improve the diagnosis and prognosis of neurosurgical patients with conditions such as brain tumors, are also described. In the end, these discoveries have led us to new frontiers in the subspecialty practice of neurosurgery. Navigating our way through these new frontiers will undoubtedly lead to additional discoveries that are unimaginable at present but bound to improve the future care of neurosurgical patients.

Local drug delivery strategies for cancer treatment: gels, nanoparticles, polymeric films, rods, and wafers

Polymer-based drug delivery depots have been investigated over the last several decades as a means to improve upon the lack of tumor targeting and severe systemic morbidities associated with intravenous chemotherapy treatments. These localized therapies exist in a variety of form factors designed to facilitate the delivery of drug directly to the site of disease in a controlled manner, sparing off-target tissue toxicities. Many of these depots are biodegradable and designed to maintain therapeutic concentrations of drug at the tumor site for a prolonged period of time. Thus a single implantation procedure is required, sometimes coincident with tumor excision surgery, and thereby biodegrading following complete release of the loaded active agent. Even though localized polymer depot delivery systems have been investigated, a surprisingly small subset of these technologies has demonstrated potentially curative preclinical results for cancer applications, and fewer have progressed toward commercialization. The aims of this article are to review the most well-studied and efficacious local polymer delivery systems from the last two decades, to examine the rationale for utilizing drug-eluting polymer implants in cancer patients, and to identify the patient cohorts that could most benefit from localized therapy. Finally, a discussion of the physiological barriers to localized therapy (i.e. drug penetration, transport), technical hurdles, and future outlook of the field is presented.

Magnetic resonance imaging appearance and changes on intracavitary Gliadel wafer placement: A pilot study

AIM: To investigate changes on magnetic resonance imaging (MRI) which occur with intracavitary Gliadel wafer placement in patients with glioblastoma multiforme (GBM).

METHODS: This retrospective Health Insurance Portability and Accountability Act-compliant study was approved by the institutional review board, with a waiver of informed consent. A total of eight patients aged 29-67 years with GBM underwent Gliadel wafer placement. T2-weighted/FLAIR images and post-contrast T1-weighted images both before and after wafer placement were retrospectively reviewed in consensus to determine changes in the following parameters: appearance of the pericavitary tissue, pattern of tumor recurrence or progression and appearance of the Gliadel wafer itself.

RESULTS: Five out of the eight patients had a progressive increase in enhancement and pericavitary T2/ FLAIR hyperintensity within the first 2 mo and a subsequent decrease in these MRI findings. None of these patients had tumor recurrence within the first 6 mo. Three out of the eight patients demonstrated a progressive increase in enhancement and pericavitary T2 hyperintensity, which continued after the first 6 mo, and were subsequently diagnosed with true tumor progression. There was no increase in distant/nonlocal tumor recurrence. The Gliadel wafer appearance changed over time.

CONCLUSION: Pseudoprogression is common after intracavitary Gliadel wafer placement and thus care should be taken before diagnosing tumor progression or recurrence within the first 2 mo.

The efficacy of carmustine wafers for older patients with glioblastoma multiforme: prolonging survival

OBJECTIVE

Peak incidence of glioblastoma multiforme (GBM) occurs in individuals aged 65 years and older. The goal was to evaluate the efficacy of carmustine wafers in prolonging survival for older GBM patients.

METHODS

One hundred and thirty-three consecutive patients aged 65 years and older who underwent surgery for an intracranial primary (de novo) GBM from 1997-2007 were retrospectively reviewed. Among these 133 patients, 45 patients with carmustine wafer implantation were matched with 45 patients without implantation. These groups were matched for factors consistently shown to be associated with survival (age, Karnofsky performance scale, extent of resection, radiation therapy, and temozolomide). Survival was expressed as estimated Kaplan-Meier plots, and log-rank analysis was used to compare survival curves. Variables with P<0.05 were considered statistically significant.

RESULTS

The mean (±standard deviation) age of the cohort was 73±5 years, and the median survival of the entire cohort was 5.9 months. Among patients with and without carmustine wafers, there were no significant differences in pre- and peri-operative variables. However, patients with carmustine wafers demonstrated prolonged survival as compared to patients without wafers. The median survival for patients with carmustine wafers was 8.7 months, while median survival for patients without wafers was 5.5 months (P=0.007). Likewise, in subgroup analysis, patients older than 70 years (P=0.0003) and 75 years (P=0.04) who had carmustine wafers had significantly longer survival than matched patients without wafers.

DISCUSSION

Older patients with GBM may benefit from carmustine wafers. The survival for older patients who received carmustine wafers is significantly longer than matched patients who did not receive carmustine wafers.

Glioblastoma multiforme: Molecular characterization and current treatment strategy (Review)

Glioblastoma multiforme (GBM) is the most common and lethal malignant primary brain tumor. It is classified by the World Health Organization (WHO) in the group of diffusely infiltrating astrocytomas, representing up to 50% of all primary brain gliomas, and carries the poorest prognosis. Aberrant genetic events and signaling pathways have clearly demonstrated that GBM is highly anaplastic and a morphologically highly heterogeneous tumor. Understanding the genetic alterations, specific molecular biomarkers and proliferative pathways may promote therapeutic development for the management of GBM. Age, Karnofsky performance score, histology, position and the extent of tumor resection have been identified as potential prognostic factors for patients with GBM. In this study, we review the molecular characterization of tumor cells, the current standard of care for patients diagnosed with GBM, including gross or near-total resection of the tumor, followed by radiotherapy, stereotactic brachytherapy, chemotherapy and new targeted therapies. Thus, we conclude that multimodal approaches for the treatment of patients with GBM may significantly improve their prognoses.

Efficacy of gamma knife radiosurgery for small-volume recurrent malignant gliomas after initial radical resection

OBJECTIVE

To review the authors' experience with Gamma Knife radiosurgery (GKR) for small recurrent high-grade gliomas (HGGs) following prior radical resection, external-beam radiation therapy (EBRT), and chemotherapy with temozolomide (TMZ).

METHODS

The authors retrospectively analyzed 26 consecutive adults (9 women and 17 men; median age 60.4 years; Karnofsky Performance Status [KPS]≥70) who underwent GKR for recurrent HGGs from 2004-2009. Median lesion volume was 1.22 cc, and median treatment dose was 15 Gy. Pathology included glioblastoma multiforme (GBM; n=16), anaplastic astrocytoma (AA; n=5), and anaplastic mixed oligoastrocytoma (AMOA; n=5). Two patients lost to follow-up were excluded from radiographic outcome analyses.

RESULTS

Median overall survival (OS) for the entire cohort from the time of GKR was 13.5 months. Values for 12-month actuarial survival from time of GKR for GBM, AMOA, and AA were 37%, 20% and 80%. Local failure occurred in 9 patients (37.5%) at a median time of 5.8 months, and 18 patients (75%) experienced distant progression at a median of 4.8 months. Complications included radiation necrosis in two patients and transient worsening of hemiparesis in one patient. Multivariate hazard ratio (HR) analysis showed KPS 90 or greater, smaller tumor volumes, and increased time to recurrence after resection to be associated with longer OS following GKR.

CONCLUSIONS

GKR provided good local tumor control in this group of clinically stable and predominantly high-functioning patients with small recurrent HGGs after radical resection. Meaningful survival times after GKR were seen. GKR can be considered for selected patients with recurrent HGGs.

Heat shock protein-peptide complex in the treatment of glioblastoma

Vaccination immunotherapies offer the promise of long-term tumor control, and preclinical trials have found promising results. Active immunotherapy uses the adaptive immune response to specifically kill tumor cells. Tumor-specific antigens are processed by antigen-presenting cells and recognized by specific effector lymphocytes. However, basic vaccination strategies with tumor lysates have been unsuccessful in inducing antiglioma immunity in clinical trials. Gliomas are known to modulate the activity of antigen-presenting cells to reduce antitumor immune activity. Recently, tumor-derived heat shock proteins have been found to more effectively activate the immune response. Widely expressed, heat shock proteins are thought to present protein peptide fragments in a format conducive to processing by antigen-presenting cells. As a part of the protein synthesis machinery, peptides complexed with heat shock proteins are effectively representative of antigens expressed by the cell; these peptides convey the specificity of this vaccination strategy. The heat shock protein-peptide vaccine is one of many promising immunotherapeutic strategies being evaluated in clinical trials. These can be broadly classified as active, passive and adoptive, each with advantages and disadvantages. Here, we compare and contrast heat shock protein-peptide vaccines with other immunotherapies and describe the outcomes of clinical trials to date.

Bevacizumab improves quality of life in patients with recurrent glioblastoma

Objective. To quantify the benefits in survival and quality of life in patients receiving bevacizumab (BEV) for recurrent glioblastoma (GBM). Methods. This is a retrospective study of 40 adult patients with recurrent GBM treated between 2005 and 2009 at a single institution. All patients had initial treatment with surgery, radiation, and concurrent temozolomide, then monthly temozolomide. Over 250 charts were screened. Sufficient data was available for 20 patients treated with BEV and 20 patients who did not receive BEV at the time of recurrence. The independent living score (ILS), designed to reward long-term independent survival, was calculated for each patient. Results. The mean ILS was nearly double in the BEV group compared to the No-BEV group (15.0 versus 8.2, P = 0.002, t-test). Two months after initiation of therapy, the median steroid dose dropped by over 90% in patients treated with BEV, but doubled in the NoBEV group. Median survival from the time of recurrence was significantly affected: 10.6 months in the BEV group versus 4.2 months (P < 0.001, log rank survival) in the NoBEV group. Conclusions. BEV increases independent living and lengthens overall survival after GBM recurrence. Reduction in steroid dose may contribute to prolonged independence.

Current concepts and management of glioblastoma

Glioblastoma is the most common malignant primary brain tumor in adults. Its often rapid clinical course, with many medical and psychosocial challenges, requires a multidisciplinary management. Modern multimodality treatment and care improve patients' life expectancy and quality of life. This review covers major aspects of care of glioblastoma patients with a focus on the management of common symptoms and complications. We aim to provide a guide for clinicians confronted with glioblastoma patients in their everyday practice.

Emerging insights into the molecular biology of brain metastases

One of the foremost challenges in oncology is developing improved therapies for preventing and treating metastases to the brain. Recent research in this area is bringing about a shift in the understanding of brain metastases. Previously, the occurrence and poor outcomes associated with brain metastases have been largely attributed to the exclusion of anticancer drugs from the brain by the blood-brain barrier (BBB). However, studies in multiple tumor types have also demonstrated that brain metastases have significant molecular differences from primary tumors and extracranial metastases. These molecular differences may not only promote the formation of brain metastases, but they may also contribute to these tumors' poor responsiveness to therapies. Such changes may be intrinsic to the cancer cells or driven by unique interactions with the brain microenvironment. An improved understanding of the molecular characteristics of brain metastases that contribute to their aggressive behaviors will facilitate the development of rational, more effective treatments for these tumors.

A novel polymer gel for the delivery of local therapies to intracranial tumors: In vivo safety evaluation

The treatment of intracranial malignancies is limited by the ability of systemically administered therapies to cross the blood-brain barrier. Royer resorbable matrix, or R-Gel, is a dextran polymer administered in liquid form via needle injection. Within minutes of preparation, the polymer forms a gel and subsequently solidifies, thereby conforming to the dimensions of the injection cavity. R-Gel can accommodate a wide variety of therapeutic agents that may provide new options for local treatment delivery. This preclinical study evaluates the neurotoxicity of R-Gel implanted in the rat brain. Fifteen rats underwent intracranial administration of R-Gel (N = 9) or saline (N = 6) were monitored for systemic and neurotoxicity, and sacrificed at pre-determined time points. Animals that received the R-Gel injection demonstrated no behavioral changes or weight loss. Histopathologic analysis revealed an inflammatory response in both groups on day 3 and day 7 after implantation, which resolved by day 42. These results suggest that intracranial R-Gel is well tolerated. Therapeutic studies of chemotherapy-complexed R-Gel are underway.

Preparation of curcumin loaded poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) nanofibers and their in vitro antitumor activity against Glioma 9L cells

The purpose of this work was to develop implantable curcumin-loaded poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCL-PEG-PCL, PCEC) nanofibers, which might have potential application in cancer therapy. Curcumin was incorporated into biodegradable PCEC nanofibers by electrospinning method. The surface morphology of the composite nanofibers was characterized on Scanning Electron Microscope (SEM). The average diameter of the nanofibers was 2.3-4.5μm. In vitro release behavior of curcumin from the fiber mats was also studied in detail. The in vitro cytotoxicity assay showed that the PCEC fibers themselves did not affect the growth of rat Glioma 9L cells. Antitumor activity of the curcumin-loaded fibers against the cells was kept over the whole experiment process, while the antitumor activity of pure curcumin disappeared within 48 h. These results strongly suggested that the curcumin/PCEC composite nanofibers might have potential application for postoperative chemotherapy of brain cancers.

Re-irradiation with radiosurgery for recurrent glioblastoma multiforme

Local tumor control remains a significant challenge in patients with glioblastoma multiforme (GBM). Despite aggressive radiation therapy approaches, most recurrences are within the high-dose field, limiting the ability to safely re-irradiate recurrence using conventional techniques. Fractionated stereotactic radiosurgery (fSRS) is a technique whose properties make it useful for re-irradiation. We retrospectively reviewed the charts of 14 patients with recurrent GBM treated with salvage radiosurgery. Seven patients were male and seven were female with a median age of 58 (range: 39-76). All patients had prior cranial radiation therapy to a median dose of 60 Gy (58-69). There were 18 lesions treated with a median tumor volume of 6.97 cm3 (0.54-50.0 cm3). fSRS was delivered in 1-3 fractions to a median dose of 24 Gy (18-30 Gy). Median follow-up for the cohort was 8 months (3-22 months). On follow-up MRI, 8 of 18 lesions had a radiographic response. The median time-to-progression following primary irradiation was 8 months (1-28 months) while the median time-to-progression (TTP) following fSRS was 5 months (1-16 months). Median local control following re-irradiation was 5 months and actuarial local control was 21% at 1-year. Overall survival following primary irradiation was 79% at 12 months and 46% at 2 years. Overall survival following re-irradiation was 79% at 6 months and 30% at 1 year. No significant treatment-related toxicity was seen in follow-up. These results indicate that re-irradiation for recurrent GBM using fSRS is well-tolerated and can offer a benefit in terms of progression-free survival (PFS).

A clinical trial protocol for second line treatment of malignant brain tumors with BNCT at University of Tsukuba

We have evaluated the efficacy and safety of boron neutron capture therapy (BNCT) for recurrent glioma and malignant brain tumor using a new protocol. One of the two patients enrolled in this trial is a man with recurrent glioblastoma and the other is a woman with anaplastic meningioma. Both are still alive and no severe adverse events have been observed. Our findings suggest that NCT will be safe as a palliative therapy for malignant brain tumors.

Paclitaxel-eluting polymer film reduces locoregional recurrence and improves survival in a recurrent sarcoma model: a novel investigational therapy

BACKGROUND

Locoregional recurrences occur in up to 50% of patients after macroscopically complete (R0/R1) resections of abdominal, pelvic, and retroperitoneal sarcomas. Efficacy of a drug-eluting polymer film in reducing locoregional recurrence rates was assessed in a murine recurrent sarcoma model.

METHODS

Poly(glycerol monostearate-co-caprolactone) polymer films were synthesized with and without 300 μg paclitaxel (Pax-film and unloaded film). Cytotoxicity was assessed against CS-1 (human chondrosarcoma) cells in vitro and in vivo in nude mice. Following R0/R1 resection of primary subcutaneous tumors, mice were blindly randomized to: (1) Pax-film implant, (2) unloaded film implant, (3) paclitaxel 300 μg IV (Pax IV), or (4) no other therapy ("untreated"). Locoregional recurrence, overall survival (OS), and tumor mitotic index were evaluated.

RESULTS

Pax-films, but not unloaded films, reduced CS-1 viability in vitro for >50 days (P < 0.001). In vivo, locoregional recurrence was observed in 2 of 12 Pax-film mice (17%), 9 of 13 unloaded film mice (69%), 8 of 9 Pax IV mice (89%), and 7 of 8 untreated mice (88%) (P < 0.01). Median OS was 81, 64, 48, and 56 days, respectively. Paclitaxel levels in local tissues were 50- to 300-fold greater in Pax-film mice compared with Pax IV mice. Tumor mitotic index adjacent to Pax-films was significantly lower than adjacent to unloaded films.

CONCLUSIONS

Tumor bed implantation of Pax-films after R0/R1 resection is superior to Pax IV as evidenced by reduced locoregional recurrence and improved OS in a murine recurrent sarcoma model. Continuous local drug exposure via polymer films represents a potentially novel approach for treatment of locally aggressive sarcomas.

Recurrent high-grade glioma

OPINION STATEMENT

Opinions vary on the best treatment options for recurrent high-grade glioma. Some argue that bevacizumab should become standard of care for patients with recurrent glioblastoma, especially in light of recent FDA approval for this indication. However, this opinion is not uniformly accepted. Age, performance status, histology, tumor size and location, O6-methylguanine-DNA methyltransferase (MGMT) methylation status for glioblastoma, 1p/19q status for oligodendroglial tumors, and the number and types of prior therapies are important considerations. In addition, recurrent disease must be distinguished from "pseudoprogression" due to treatment effects. Enrollment in a clinical trial is the optimal choice for most patients with recurrent high-grade glioma after failure of radiation therapy and temozolomide. For patients who are ineligible or do not have access to clinical trials, then either bevacizumab monotherapy or bevacizumab in combination with a second agent such as irinotecan is recommended. Involved-field external beam radiation should be considered for patients with anaplastic gliomas who have not received radiation. For patients with anaplastic astrocytoma who progress after radiotherapy, temozolomide may be used. For patients with anaplastic oligodendroglioma who progress after radiotherapy, PCV chemotherapy and temozolomide are options. Oligodendroglial tumors with 1p/19q deletions are more likely to respond to treatment. In the past, carmustine was commonly used to treat recurrent high-grade glioma, but the utility of carmustine in the modern era is unknown because most studies were performed prior to the widespread use of temozolomide. High-precision re-irradiation such as stereotactic radiosurgery is another option in high-grade glioma, especially for patients with poor bone marrow reserve or inability to tolerate chemotherapy, but there is a paucity of studies with adequate controls. Surgery may be useful as adjuvant treatment for patients with symptoms due to mass effect or for patients requiring definitive histopathology, but it generally should be combined with another treatment modality. Emerging therapies, including dose-intense temozolomide regimens, targeted molecular inhibitors, other antiangiogenic therapies, viral gene therapies, immunotherapies, and convection-enhanced delivery of targeted immunotoxins, are still under investigation.

Glioblastoma multiforme

Optimal management of newly diagnosed glioblastoma multiforme includes maximal surgical resection, followed by 60 Gy of external beam radiation plus concomitant daily temozolomide and at least six additional monthly cycles of maintenance temozolomide. Several large phase 3 trials are now ongoing to determine whether agents added to this regimen may confer further survival advantage. At the time of disease recurrence, bevacizumab is the most commonly used agent. Whenever feasible, patients should be encouraged to participate in clinical trials, which are currently focused on antiangiogenic and targeted therapies.

The efficacy of intracranial PLG-based vaccines is dependent on direct implantation into brain tissue

We previously engineered a macroporous, polymer-based vaccine that initially produces GM-CSF gradients to recruit local dendritic cells and subsequently presents CpG oligonucleotides, and tumor lysate to cell infiltrates to induce immune cell activation and immunity against tumor cells in peripheral tumor models. Here, we demonstrate that this system eradicates established intracranial glioma following implantation into brain tissue, whereas implantation in resection cavities obviates vaccine efficacy. Rats bearing seven-day old, intracranial glioma tumors were treated with PLG vaccines implanted into the tumor bed, resulting in retention of contralateral forelimb function (day 17) that is compromised by tumor formation in control animals, and 90% long-term survival (>100 days). Similar benefits were observed in animals receiving tumor resection plus vaccine implants into the adjacent parenchyma, but direct implantation of PLG vaccines into the resection cavity conferred no benefit. This dissociation of efficacy was likely related to GM-CSF distribution, as implantation of PLG vaccines within brain tissue produced significant GM-CSF gradients for prolonged periods, which was not detected after implantation in resection cavities. These studies demonstrate that PLG vaccine efficacy is correlated to GM-CSF gradient formation, which requires direct implantation into brain tissue, and justify further exploration of this approach for glioma treatment.

Convection-enhanced delivery of 131I-chTNT-1/B mAB for treatment of high-grade adult gliomas

INTRODUCTION

Despite treatment advances for malignant gliomas in adults, prognosis remains poor, largely due to the infiltrative and heterogeneous biology of these tumors. Response to adjuvant therapy is not always uniform and the blood-brain barrier prevents the majority of chemotherapeutics from adequately reaching primary tumor sites. These obstacles necessitate development of novel delivery methods and agents.

AREAS COVERED

(131)I-chTNT-1/B mAB (Cotara) is a genetically engineered chimeric monoclonal antibody that binds to the DNA-histone H1 complex. It carries (131)I, which delivers sufficient energy to kill adjacent tumor cells. Through convection-enhanced delivery (CED) it provides radioimmunotherapy directly to the resection cavity. We review the pharmacology and clinical experience with (131)I-chTNT-1/B mAB, detailing results of completed Phase I and II trials.

EXPERT OPINION

Novel agents and therapeutic modalities, such as (131)I-chTNT-1/B mAB, are of interest for treatment of malignant glioma, for which the prognosis continues to be dismal. (131)I-chTNT-1/B mAB targets tumor cells and radioisotope labeling allows radiation delivery to the tumor with sharp fall-off. Data from Phase I and II trials of CED delivery of (131)I-chTNT-1/B mAB shows it is well tolerated. Phase II trial data suggests it could be promising therapeutically, though conclusions about efficacy require further trials and clinical experience. The compound is currently in a Phase II trial for dose confirmation in patients with malignant gliomas.

Salvage therapy with single agent bendamustine for recurrent glioblastoma

The treatment of recurrent glioblastoma (GBM) remains challenging notwithstanding the recent approval of bevacizumab for this indication. Bendamustine has a bifunctional mechanism of action including alkylation, penetrates the CNS and does not show cross resistance to other alkylator chemotherapies. In a single institution phase 2 trial, patients with recurrent GBM were treated with bendamustine (100 mg/m(2)/day administered intravenously for two consecutive days every 4 weeks). The primary study endpoint was 6-month progression free survival (PFS-6). An interim analysis for futility was conducted according to a Simon two-stage minimax design. Complete blood counts were obtained bimonthly, clinical evaluations and brain imaging every month for the first cycle and bimonthly thereafter. Treatment responses were based upon MacDonald criteria. Sixteen patients were enrolled (nine men; seven women), with a median age of 53 years (range 36-68) and a median Karnofsky performance status of 90 (range 70-100). Nine patients were treated at first relapse and seven at second relapse (five patients were bevacizumab failures). A total of 25 cycles of bendamustine were administered with a median of 1 (range 1-6). Bendamustine-related toxicity was seen in eight patients; lymphopenia in seven (5 grade 3; 2 Grade 4), thrombocytopenia in two (1 Grade 3; 1 Grade 4), and neutropenia in one (1 Grade 3). Fourteen patients have died due to disease progression, two patients are alive and on alternative therapies. Only one patient was progression-free at 6 months, triggering the stopping rule for futility. Bendamustine was reasonably well tolerated but failed to meet the study criteria for activity in adults with recurrent GBM.

Should we reoperate for recurrent high-grade astrocytoma?

Despite optimal treatment of post-operative radiotherapy and chemotherapy for newly diagnosed high-grade astrocytoma, nearly all patients eventually recur. However, the efficacy of reoperation for recurrent astrocytoma is still debatable as to different surgical indications. To investigate the therapeutic effect of reoperation on patients with recurrent high-grade astrocytoma more objectively, a retrospective case-matched study was carried out. The clinical data of 63 cases of recurrent high-grade astrocytoma treated between January 2006 and December 2008 were studied. A total of 21 cases received reoperation immediately after tumor recurrence, while 42 cases without reoperation were matched by gender, age, Karnofsky Performance Scale (KPS) score, histopathology, recurrent interval after the first operation, extent of initial surgery, adjuvant treatment and characteristics of recurrent tumor. The study showed that the median survival time was 7 months in the reoperation group, while in non-reoperation group, it was 4 months. There was significant difference on univariate analysis (P < 0.001). Moreover, the median duration time of progression-free survival (PFS) after tumor recurrence was significantly (P < 0.001) longer in the reoperation group (5 months) than that in the non-reoperation group (2.5 months). The prognostic factors of recurrent high-grade astrocytoma included reoperation, KPS score and tumor location. It was indicated that reoperation could prolong the survival time and improve the quality of survival in patients of recurrent high-grade astrocytoma.

Postoperative seizure in high grade glioma patients treated with BCNU wafers. A mono-institutional experience

Anticonvulsant therapy is usually recommended before surgery in all patients affected by high grade glioma who are planned to be treated with Carmustine 1,3-bis [2 chloroetyl]-1-nitrosurea, or BCNU) wafers. In fact, phase III studies have reported a risk of seizures higher than 30% in this group of patients. The aim of the study was the evaluation of rate type time of occurrence of seizures in BCNU-treated patients in the postoperative period as well as the investigation into possible risk factors for seizure occurrence in this population. From April 2007 to September 2010, 55 patients underwent surgical removal of malignant glioma and BCNU wafers implantation at the Department of Neurosurgery of Padova. All patients were given antiepileptic prophylaxis for 3 months after surgery. Clinical data (including preoperative seizure history), radiological data, surgical treatment, antiepileptic treatment were retrospectively reviewed. Nine percent of the patients treated with BCNU wafers presented seizures in the postoperative course. Seizures were partial in 80% of cases; they occurred within 30 days after surgery and in 80% of cases within the first 7 days. Patients with preoperative seizures presented more frequently postoperative epilepsy than patients who were preoperatively seizure-free [P = 0.0006; OR = 48 (2,4;945)]. Postoperative seizures were more common among patients affected by one or more wafers related adverse event than among patients without adverse events [P = 0.006; OR = 21 (2,06;213)]; however, they did not appear associated to the number of implanted wafers. Patients with a sub-therapeutic level of AED at the seventh day after surgery presented a higher seizure occurrence [P = 0.02; OR = 11 (1,5;79,8)]. In our experience, postoperative seizures in BCNU-treated patients were less frequent than expected. Careful patient selection and postoperative monitoring could probably play a role in order to decrease seizure occurrence.

PLGA nanoparticles containing various anticancer agents and tumour delivery by EPR effect

As mortality due to cancer continues to rise, advances in nanotechnology have significantly become an effective approach for achieving efficient drug targeting to tumour tissues by circumventing all the shortcomings of conventional chemotherapy. During the past decade, the importance of polymeric drug-delivery systems in oncology has grown exponentially. In this context, poly(lactic-co-glycolic acid) (PLGA) is a widely used polymer for fabricating 'nanoparticles' because of biocompatibility, long-standing track record in biomedical applications and well-documented utility for sustained drug release, and hence has been the centre of focus for developing drug-loaded nanoparticles for cancer therapy. Such PLGA nanoparticles have also been used to develop proteins and peptides for nanomedicine, and nanovaccines, as well as a nanoparticle-based drug- and gene-delivery system for cancer therapy, and nanoantigens and growth factors. These drug-loaded nanoparticles extravasate through the tumour vasculature, delivering their payload into the cells by the enhanced permeability and retention (EPR) effect, thereby increasing their therapeutic effect. Ongoing research about drug-loaded nanoparticles and their delivery by the EPR effect to the tumour tissues has been elucidated in this review with clarity.

Chemotherapy wafers for high grade glioma

BACKGROUND

Standard treatment for high grade glioma (HGG) usually entails surgery (either biopsy or resection) followed by radiotherapy plus or minus temozolomide. Implanting wafers impregnated with chemotherapy agents into the resection cavity represents a novel means of delivering drugs directly to the resection cavity with potentially fewer systemic side effects. It is not clear how effective this modality is or whether it should be recommended as part of standard care for patients with HGG.

OBJECTIVES

To estimate the clinical effectiveness of chemotherapy wafers for patients with HGG.

SEARCH STRATEGY

The following databases were searched: CENTRAL (issue 4. 2010); MEDLINE and EMBASE. The original search strategy also included: Science Citation Index; Physician Data Query; and the meta-Register of Controlled Trials. Reference lists of all identified studies were searched. The Journal of Neuro-Oncology and Neuro-oncology were hand searched from 1999 to 2010, including all conference abstracts. Neuro-oncologists, trial authors and drug manufacturers were contacted regarding ongoing and unpublished trials.

SELECTION CRITERIA

Patients included those of all ages with a histologically proven diagnosis of HGG (using intra-operative analysis when undergoing first resection). Therapy could be instigated for either newly diagnosed disease (primary therapy) or at recurrence. Interventions included insertion of chemotherapy wafers to the resection cavity. Included studies had to be randomised controlled trials (RCTs).

DATA COLLECTION AND ANALYSIS

Two independent review authors assessed the search results for relevance and undertook critical appraisal according to pre-specified guidelines.

MAIN RESULTS

In primary disease two RCTs assessing the effect of carmustine impregnated wafers (Gliadel®) and enrolling a total of 272 participants were identified. Survival was increased with Gliadel® compared to placebo (hazard ratio (HR) 0.65, 95% Confidence Interval (CI) 0.48 to 0.86, P = 0.003). In recurrent disease a single RCT was included comparing Gliadel® with placebo and enrolled 222 participants. It did not demonstrate a significant survival increase (HR 0.83, 95% CI 0.62 to 1.10, P = 0.2). There was no suitable data for any of the secondary outcome measures. Adverse events were not more common in either arm and are presented in a descriptive fashion.

AUTHORS' CONCLUSIONS

Carmustine impregnated wafers (Gliadel®) result in improved survival without an increased incidence of adverse events over placebo wafers when used for primary disease therapy. There is no evidence of benefit for any other outcome measures. In recurrent disease Gliadel® does not appear to confer any additional benefit.

A phase I/II trial of the histone deacetylase inhibitor romidepsin for adults with recurrent malignant glioma: North American Brain Tumor Consortium Study 03-03

Romidepsin, a potent histone deacetylase inhibitor, has shown activity in preclinical glioma models. The primary objectives of this trial were to determine the pharmacokinetics of romidepsin in patients with recurrent glioma on enzyme-inducing antiepileptic drugs (EIAEDs) and to evaluate the antitumor efficacy of romidepsin in patients with recurrent glioblastoma who were not receiving EIAEDs. Two dose cohorts were studied in the phase I component of the trial (13.3 and 17.7 mg/m(2)/d). Patients in the phase II component were treated with intravenous romidepsin at a dosage of 13.3 mg/m(2)/day on days 1, 8, and 15 of each 28-day cycle. Eight patients were treated on the phase I component. A similar romidepsin pharmacokinetic profile was demonstrated between patients receiving EIAEDs to those not receving EIAEDs. Thirty-five patients with glioblastoma were accrued to the phase II component. There was no objective radiographic response. The median progression-free survival (PFS) was 8 weeks and only 1 patient had a PFS time ≥6 months (PFS6 = 3%). To date, 34 patients (97%) have died, with a median survival duration of 34 weeks. Despite in vitro studies showing that romidepsin is primarily metabolized by CYP3A4, no decrease in exposure to romidepsin was seen in patients receiving potent CYP3A4 inducers. Romidepsin, at its standard dose and schedule, was ineffective for patients with recurrent glioblastomas. ClinicalTrials.gov identifier: NCT00085540.

Occlusion of surgical opening of the ventricular system with fibrinogen-coated collagen fleece: a case collection study

Background

Implantation of 1,3-bis (2-chloroethyl)-1-nitrosourea (BCNU) wafer for malignant glioma is not recommended in the case of surgical opening of the ventricular system during microsurgical tumor resection because the wafer material may dislocate from the resection cavity into the ventricular system and cause obstructive hydrocephalus. TachoSil is an adhesive collagen fleece used in different surgical disciplines that provides an air- and liquid-tight seal closing communications between the ventricular system and the resection cavity after tumor removal.

Methods

Occlusion of ventricular defects with TachoSil after microsurgical glioma resection was performed in two patients with newly diagnosed and seven patients with recurrent malignant glioma prior to BCNU wafer implantation into the resection cavity. Early postoperative cranial computed tomography (CCT)/MRI and follow-up MRI at 3 months’ intervals were performed with a median follow-up of 10.4 months.

Results

The collagen fleece was identified as a linear structure hypodense/hypointense to white matter on postoperative CT/MRI separating the resection cavity from the ventricular lumen in all cases. In no case did early CCT/MRI or follow-up MRI reveal wafer material within the ventricular system. In no case did signs of obstructive hydrocephalus occur.

Conclusion

Sealing of the ventricular system using a fibrinogen-coated collagen fleece effectively separates the resection cavity from the ventricular system and allows implantation of BCNU wafers into the resection cavity. No morphological evidence for wafer material dislocation into the ventricular system or obstruction of CSF pathways was found in nine patients who received 41 follow-up MRI over 10.4 months of follow-up.

An acetylated polysaccharide-PTFE membrane-covered stent for the delivery of gemcitabine for treatment of gastrointestinal cancer and related stenosis

Gemcitabine (Gem) eluting metal stents were prepared for potential application as drug delivery systems for localized treatment of malignant tumors. Pullulan, a natural polysaccharide, was chemically acetylated (pullulan acetate; PA) by different degrees (1.18, 1.71, and 2.10 acetyl groups per glucose unit of pullulan), layered on polytetrafluoroethylene (PTFE), and applied as part of a Gem-loaded controlled-release membrane for drug-eluting non-vascular stents. PA with a higher degree of acetylation had greater drug-loading capacity with more extended release of Gem over 30 days. The released Gem accumulated in CT-26 colon cancer without systemic exposure inducing total regression of tumors. The long-term biological activity of the released Gem and apoptosis of tumor tissues following localized delivery were confirmed by annexin V binding assays and histology. The controlled release of Gem from PA-PTFE covered drug-eluting stents (DES) may increase the patency of these stents for the treatment of malignant gastrointestinal cancer as well as cancer-related stenosis.

Space-occupying cyst development in the resection cavity of malignant gliomas following Gliadel® implantation--incidence, therapeutic strategies, and outcome

Gliadel® (Eisai Inc., Woodcliff Lake, NJ, USA) is the only therapeutic agent approved by the Food and Drug Administration and the European Medicines Agency for local chemotherapy of malignant gliomas. With increasing use of this treatment, characteristic side effects have become evident. While most side effects can be managed conservatively, cyst formation requires further intervention. From 2004 to 2009 at our institution 88 patients with malignant gliomas were treated with Gliadel®. Ten patients (11%) developed a space-occupying cyst in the resection cavity, seven of which caused clinical symptoms of mass effect that was most prominent 2 weeks after Gliadel® implantation (median=16, range=9-30). Despite dexamethasone treatment symptoms progressed, necessitating various surgical interventions. In four patients the cysts were drained percutaneously through a burrhole using a 19-gauge needle. If puncture was not possible (three patients) or not sufficient (two patients), an Ommaya reservoir was implanted for repetitive drainage. In two patients this treatment was combined with open decompression of the cyst. On average, cysts were drained three times. Eventually the symptoms subsided, corresponding to shrinkage of the cysts as shown on follow-up imaging. We describe a serious side effect of local chemotherapy, which may cause rapid clinical deterioration and require direct intervention. While reservoir implantation apparently represents a more elegant treatment option, our experience shows that draining the cyst, even only a few times, sufficiently ameliorates the symptoms and subsequently reverses and halts further cyst enlargement.

Biomaterial-based vaccine induces regression of established intracranial glioma in rats

PURPOSE

The prognosis for glioma patients is poor, and development of new treatments is critical. Previously, we engineered polymer-based vaccines that control GM-CSF, CpG-oligonucleotide, and tumor-lysate presentation to regulate immune cell trafficking and activation, which promoted potent immune responses against peripheral tumors. Here, we extend the use of this system to glioma.

METHODS

Rats were challenged with an intracranial injection of glioma cells followed (1 week) by administration of the polymeric vaccine (containing GM-CSF, CpG, and tumor-lysate) in the tumor bed. Control rats were treated with blank matrices, matrices with GM-CSF and CpG, or intra-tumoral bolus injections of GM-CSF, CpG, and tumor lysate. Rats were monitored for survival and tested for neurological function.

RESULTS

Survival studies confirmed a benefit of the polymeric vaccine as 90% of vaccinated rats survived for > 100 days. Control rats exhibited minimal benefit. Motor tests revealed that vaccination protected against the loss of forelimb use produced by glioma growth. Histological analysis quantitatively confirmed a robust and rapid reduction in tumor size. Long-term immunity was confirmed when 67% of survivors also survived a second glioma challenge.

CONCLUSIONS

These studies extend previous reports regarding this approach to tumor therapy and justify further development for glioma treatment.

Intracranial microcapsule drug delivery device for the treatment of an experimental gliosarcoma model

Controlled-release drug delivery systems are capable of treating debilitating diseases, including cancer. Brain cancer, in particular glioblastoma multiforme (GBM), is an extremely invasive cancer with a dismal prognosis. The use of drugs capable of crossing the blood-brain barrier has shown modest prolongation in patient survival, but not without unsatisfactory systemic, dose-limiting toxicity. Among the reasons for this improvement include a better understanding of the challenges of delivery of effective agents directly to the brain tumor site. The combination of carmustine delivered by biodegradable polyanhydride wafers (Gliadel(®)), with the systemic alkylating agent, temozolomide, allows much higher effective doses of the drug while minimizing the systemic toxicity. We have previously shown that locally delivering these two drugs leads to further improvement in survival in experimental models. We postulated that microcapsule devices capable of releasing temozolomide would increase the therapeutic capability of this approach. A biocompatible drug delivery microcapsule device for the intracranial delivery of temozolomide is described. Drug release profiles from these microcapsules can be modulated based on the physical chemistry of the drug and the dimensions of the release orifices in these devices. The drug released from the microcapsules in these experiments was the clinically utilized chemotherapeutic agent, temozolomide. In vitro studies were performed in order to test the function, reliability, and drug release kinetics of the devices. The efficacy of the temozolomide-filled microcapsules was tested in an intracranial experimental rodent gliosarcoma model. Immunohistochemical analysis of tissue for evidence of DNA strand breaks via terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay was performed. The experimental release curves showed mass flow rates of 36 μg/h for single-orifice devices and an 88 μg/h mass flow rate for multiple-orifice devices loaded with temozolomide. In vivo efficacy results showed that localized intracranial delivery of temozolomide from microcapsule devices was capable of prolonging animal survival and may offer a novel form of treatment for brain tumors.