Phase II study of thalidomide and radiation in children with newly diagnosed brain stem gliomas and glioblastoma multiforme

[Diffuse brainstem tumors in children. Tumor biology and hope for a better outcome. Current state of the problem]

Diffuse brainstem tumor is a fatal disease and the main cause of child mortality from neoplasms of central nervous system. So far, no effective therapy has been found for this disease. The authors discuss the modern aspects of clinical data, biology, diagnosis and treatment of patients with diffuse brainstem tumors.

Pediatric Neuro-Oncology

Central nervous system (CNS) tumors are the most common solid tumor in pediatrics and represent the largest cause of childhood cancer-related mortality. With advances in molecular characterization of tumors, considerable developments have occurred impacting diagnosis and management, and refined prognostication. Advances in management have led to better survival, but mortality remains high and significant morbidity persists. Novel therapeutic approaches targeting the biology of these tumors are being investigated to improve overall survival and decrease treatment-related morbidity. Further molecular understanding of pediatric CNS tumors will lead to continued refinement of tumor classification, management, and prognostication.

Children with DIPG and high-grade glioma treated with temozolomide, irinotecan, and bevacizumab: the Seattle Children's Hospital experience

INTRODUCTION

Beyond focal radiation, there is no consensus standard therapy for pediatric high-grade glioma (pHGG) and outcomes remain dismal. We describe the largest molecularly-characterized cohort of children with pHGG treated with a 3-drug maintenance regimen of temozolomide, irinotecan, and bevacizumab (TIB) following radiation.

METHODS

We retrospectively reviewed 36 pediatric patients treated with TIB at Seattle Children's Hospital from 2009 to 2018 and analyzed survival using the Kaplan-Meier method. Molecular profiling was performed by targeted DNA sequencing and toxicities, steroid use, and palliative care utilization were evaluated.

RESULTS

Median age at diagnosis was 10.9 years (18 months-18 years). Genetic alterations were detected in 26 genes and aligned with recognized molecular subgroups including H3 K27M-mutant (12), H3F3A G34-mutant (2), IDH-mutant (4), and hypermutator profiles (4). Fifteen patients (42%) completed 12 planned cycles of maintenance. Side effects associated with chemotherapy delays or modifications included thrombocytopenia (28%) and nausea/vomiting (19%), with temozolomide dosing most frequently modified. Median event-free survival (EFS) and overall survival (OS) was 16.2 and 20.1 months, with shorter survival seen in DIPG (9.3 and 13.3 months, respectively). Survival at 1, 2, and 5 years was 80%, 10% and 0% for DIPG and 85%, 38%, and 16% for other pHGG.

CONCLUSION

Our single-center experience demonstrates tolerability of this 3-drug regimen, with prolonged survival in DIPG compared to historical single-agent temozolomide. pHGG survival was comparable to analogous 3-drug regimens and superior to historical agents; however, cure was rare. Children with pHGG remain excellent candidates for the study of novel therapeutics combined with standard therapy.

Genetics of Common Pediatric Brain Tumors

Central nervous system tumors are the most common solid tumors in pediatrics and represent the largest cause of childhood cancer-related mortality. Improvements have occurred in the management of these patients leading to better survival, but significant morbidity persists. With the era of next generation sequencing, considerable advances have occurred in the understanding of these tumors both biologically and clinically. This information has impacted diagnosis and management. Subgroups have been identified, improving risk stratification. Novel therapeutic approaches, specifically targeting the biology of these tumors, are being investigated to improve overall survival and decrease treatment-related morbidity. The intent of this review is to discuss the genetics of common pediatric brain tumors and the clinical implications. This review will include known genetic disorders associated with central nervous system tumors, neurofibromatosis, tuberous sclerosis, Li-Fraumeni syndrome, Gorlin syndrome, and Turcot syndrome, as well as somatic mutations of glioma, medulloblastoma, and ependymoma.

Role of Radiation Therapy in the Management of Diffuse Intrinsic Pontine Glioma: A Systematic Review

Purpose

Diffuse intrinsic pontine glioma (DIPG) is the most aggressive primary pediatric brain tumor, with <10% of children surviving 2 years. Radiation therapy (RT) remains the mainstay of treatment, but there is a great clinical need for improvements and advancements in treatment strategies. The aim of this systematic review was to identify all available studies in which RT was used to treat patients with DIPG.

Methods and Materials

A literature search for studies published up to March 10, 2018 was conducted using the PubMed database. We identified 384 articles using search items “diffuse intrinsic pontine glioma” and 221 articles using search items “diffuse brainstem glioma radiotherapy.” Included studies were prospective and retrospective series that reported outcomes of DIPG treatment with RT.

Results

We identified 49 studies (1286 patients) using upfront conventionally fractionated RT, 5 studies (92 patients) using hypofractionated RT, and 8 studies (348 patients) using hyperfractionated RT. The mean median overall survival (OS) was 12.0 months, 10.2 months, and 7.9 months in patients who received conventional, hyperfractionated, and hypofractionated RT regimens, respectively. Patients undergoing radiosensitizing therapy had a mean median OS of 11.5 months, and patients who did not receive concomitant systemic therapy had an OS of 9.4 months. In patients who received salvage RT, the mean median OS from initial diagnosis was 16.3 months.

Conclusions

As one of the largest systematic reviews examining RT for DIPG, this report may serve as a useful tool to help clinicians choose the most appropriate treatment approach, while also providing a platform for future investigations into the utility of RT and systemic therapy.

A pediatric brain tumor consortium phase II trial of capecitabine rapidly disintegrating tablets with concomitant radiation therapy in children with newly diagnosed diffuse intrinsic pontine gliomas

BACKGROUND

We conducted a phase II study of oral capecitabine rapidly disintegrating tablets given concurrently with radiation therapy (RT) to assess progression-free survival (PFS) in children with newly diagnosed diffuse intrinsic pontine gliomas (DIPG).

PATIENTS AND METHODS

Children 3-17 years with newly diagnosed DIPG were eligible. Capecitabine, 650 mg/m² /dose BID (maximum tolerated dose [MTD] in children with concurrent radiation), was administered for 9 weeks starting the first day of RT. Following a 2-week break, three courses of capecitabine, 1,250 mg/m² /dose BID for 14 days followed by a 7-day rest, were administered. As prospectively designed, 10 evaluable patients treated at the MTD on the phase I trial were included in the phase II analyses. The design was based on comparison of the PFS distribution to a contemporary historical control (n = 140) with 90% power to detect a 15% absolute improvement in the 1-year PFS with a type-1 error rate, α = 0.10.

RESULTS

Forty-four patients were evaluable for the phase II objectives. Capecitabine and RT was well tolerated with low-grade palmar plantar erythrodyesthesia, increased alanine aminotransferase, cytopenias, and vomiting the most commonly reported toxicities. Findings were significant for earlier progression with 1-year PFS of 7.21% (SE = 3.47%) in the capecitabine-treated cohort versus 15.59% (SE = 3.05%) in the historical control (P = 0.007), but there was no difference for overall survival (OS) distributions (P = 0.30). Tumor enhancement at diagnosis was associated with shorter PFS and OS. Capecitabine was rapidly absorbed and converted to its metabolites.

CONCLUSION

Capecitabine did not improve the outcome for children with newly diagnosed DIPG.

DIPG in Children - What Can We Learn from the Past?

Brainstem tumors represent 10–15% of pediatric central nervous system tumors and diffuse intrinsic pontine glioma (DIPG) is the most common brainstem tumor of childhood. DIPG is almost uniformly fatal and is the leading cause of brain tumor-related death in children. To date, radiation therapy (RT) is the only form of treatment that offers a transient benefit in DIPG. Chemotherapeutic strategies including multi-agent neoadjuvant chemotherapy, concurrent chemotherapy with RT, and adjuvant chemotherapy have not provided any survival advantage. To overcome the restrictive ability of the intact blood–brain barrier (BBB) in DIPG, several alternative drug delivery strategies have been proposed but have met with minimal success. Targeted therapies either alone or in combination with RT have also not improved survival. Five decades of unsuccessful therapies coupled with recent advances in the genetics and biology of DIPG have taught us several important lessons (1). DIPG is a heterogeneous group of tumors that are biologically distinct from other pediatric and adult high grade gliomas (HGG). Adapting chemotherapy and targeted therapies that are used in pediatric or adult HGG for the treatment of DIPG should be abandoned (2). Biopsy of DIPG is relatively safe and informative and should be considered in the context of multicenter clinical trials (3). DIPG probably represents a whole brain disease so regular neuraxis imaging is important at diagnosis and during therapy (4). BBB permeability is of major concern in DIPG and overcoming this barrier may ensure that drugs reach the tumor (5). Recent development of DIPG tumor models should help us accurately identify and validate therapeutic targets and small molecule inhibitors in the treatment of this deadly tumor.

Thalidomide as palliative treatment in patients with advanced secondary glioblastoma

BACKGROUND

For its numerous abilities including sedation, we have been using thalidomide (TH) as the 'last therapeutic option' in patients with advanced gliomas. We noticed that a small subgroup, i.e. patients with secondary glioblastoma (GBM, whose GBM has evolved over several months or years from a less malignant glioma), survived for prolonged periods. Therefore, we retrospectively evaluated the outcomes of patients with secondary GBM treated with TH at our centre.

PATIENTS AND METHODS

Starting in the year 2000, we have studied 23 patients (13 females, 10 males, with a median age of 31.5 years) with secondary GBM who have received palliative treatment with TH 100 mg at bedtime. All patients had previously undergone radiotherapy and received at least 1 and up to 5 regimens of chemotherapy.

RESULTS

The median duration of TH administration was 4.0 months (range 0.8-32). The median duration of overall survival after the start of TH therapy was 18.3 months (range 0.8-57). Eleven patients with secondary GBM survived longer than 1 year. Symptomatic improvement was most prominent in the restoration of a normal sleep pattern.

CONCLUSION

The palliative effects of TH, especially the normalization of a sleep pattern, were highly valued by patients and families. The prolongation of survival of patients with secondary GBM has not been reported previously.

Diffuse intrinsic pontine gliomas: treatments and controversies

Diffuse intrinsic pontine gliomas (DIPGs) are a fairly common pediatric brain tumor, and children with these tumors have a dismal prognosis. They generally are diagnosed within the first decade of life, and due to their location within the pons, these tumors are not surgically resectable. The median survival for children with DIPGs is less than 1 year, in spite of decades of clinical trial development of unique approaches to radiation therapy and chemotherapy. Novel therapies are under investigation for these deadly tumors. As clinicians and researchers make a concerted effort to obtain tumor tissue, the molecular signals of these tumors are being investigated in an attempt to uncover targetable therapies for DIPGs. In addition, direct application of chemotherapies into the tumor (convection-enhanced delivery) is being investigated as a novel delivery system for treatment of DIPGs. Overall, DIPGs require creative thinking and a disciplined approach for development of a therapy that can improve the prognosis for these unfortunate children.

Pediatric diffuse intrinsic pontine glioma: can optimism replace pessimism?

Pediatric diffuse intrinsic pontine glioma (DIPG) has a dismal prognosis that has not seen a change in outcome despite multiple clinical trials. Possible reasons for failure to make progress in this aggressive childhood brain tumor include: poor understanding of the underlying molecular biology due to lack of access to tumor material; absence of accurate and relevant DIPG preclinical models for drug development; ill-defined therapeutic targets for novel agents; and inadequate drug delivery to the brainstem. This review will demonstrate that systematic studies to identify solutions for each of these barriers is starting to deliver progress that can turn pessimism to optimism in DIPG.

Effect of time from diagnosis to start of radiotherapy on children with diffuse intrinsic pontine glioma

BACKGROUND

Children with diffuse intrinsic pontine glioma (DIPG) continue to have poor outcomes, and radiotherapy (RT) is the only temporarily effective treatment. In this retrospective analysis, we studied the effect of time from diagnosis to start of RT on event-free survival (EFS) and overall survival (OS) in children with DIPG.

METHODS

Records of children (n = 95) with DIPG treated with RT at a single institution between April 1999 and September 2009 were analyzed. RT was delivered at doses of 54.0-55.8 Gy at 1.8 Gy per fraction, and children were followed prospectively. The effect of gender, race, interruption during treatment course, age at diagnosis, duration of symptoms prior to diagnosis, use of protocol-based chemotherapy, and time from diagnosis to initiation of RT on EFS and OS was assessed by the Cox proportional hazards model.

RESULTS

Time as a continuous variable from diagnosis to start of RT did not affect outcome. Time dichotomized to ≤14 days significantly affected OS (hazard ratio [HR] = 1.70, P = 0.014) and race other than white or black affected EFS (HR = 2.32, P = 0.017). The 95 patients had a 6-month EFS and OS of 60 ± 5% and 94.7 ± 2.3%, respectively, and a 12-month EFS and OS of 11.6 ± 3.1% and 49.5 ± 5%, respectively.

CONCLUSIONS

Time as a continuous variable did not affect OS or EFS in our cohort; however, children treated within 2 weeks of diagnosis had poor outcomes. Although rapid initiation of RT is desirable, our findings do not support intensive efforts aimed at shortening delays from diagnosis to start of RT.

Management of diffuse pontine gliomas in children: recent developments

The prognosis for children with diffuse intrinsic pontine gliomas (DIPGs) is dismal. Although DIPGs constitute only 10-15 % of all pediatric brain tumors, they are the main cause of death in this group with a median survival of less than 12 months. Standard therapy involves radiotherapy, which produces transient neurologic improvement. Despite several clinical trials having been conducted, including trials on targeted agents to assess their efficacy, there is no clear improvement in prognosis. However, knowledge of DIPG biology is increasing, mainly as a result of research using biopsy and autopsy samples. In this review, we discuss recent studies in which systemic therapy was administered prior to, concomitantly with, or after radiotherapy. The discussion also includes novel therapeutic options in DIPG. Continuing multimodal and multitargeted therapies might lead to an improvement in the dismal prognosis of the disease.

Brainstem gliomas

Historically, brainstem gliomas have been considered as a single entity. Since the introduction of magnetic resonance (MR) imaging in the late 1980s, these tumors are now regarded as a heterogeneous group of neoplasms with different age of onset, clinical and radiologic presentation, and varying behavior and natural history. This article describes the different subtypes of brainstem gliomas in children and adults. We focus on recent advances in MR such as MR spectroscopy, MR perfusion, and diffusion tensor imaging that often strongly suggest the histopathologic diagnosis of the lesion.

Design and conduct of early-phase radiotherapy trials with targeted therapeutics: lessons from the PRAVO experience

New strategies to facilitate the improvement of physical and integrated biological optimization of high-precision treatment protocols are an important priority for modern radiation oncology. From a clinical perspective, as knowledge accumulates from molecular radiobiology, there is a complex and exciting opportunity to investigate novel approaches to rational patient treatment stratification based on actionable tumor targets, together with the appropriate design of next-generation early-phase radiotherapy trials utilizing targeted therapeutics, to formally evaluate relevant clinical and biomarker endpoints. A unique aspect in the development pathway of systemic agents with presumed radiosensitizing activity will also be the need for special attention on patient eligibility and the rigorous definition of radiation dose-volume relationships and potential dose-limiting toxicities. Based on recent experience from systematically investigating histone deacetylase inhibitors as radiosensitizing agents, from initial studies in preclinical tumor models through the conduct of a phase I clinical study to evaluate tumor activity of the targeted agent as well as patient safety and tumor response to the combined treatment modality, this communication will summarize principles relating to early clinical evaluation of combining radiotherapy and targeted therapeutics.

The combination of novel targeted molecular agents and radiation in the treatment of pediatric gliomas

Brain tumors are the most common solid pediatric malignancy. For high-grade, recurrent, or refractory pediatric brain tumors, radiation therapy (XRT) is an integral treatment modality. In the era of personalized cancer therapy, molecularly targeted agents have been designed to inhibit pathways critical to tumorigenesis. Our evolving knowledge of genetic aberrations in pediatric gliomas is being exploited with the use of specific targeted inhibitors. These agents are additionally being combined with XRT to increase the efficacy and duration of local control. In this review, we discuss novel agents targeting three different pathways in gliomas, and their potential combination with XRT. BRAF is a serine/threonine kinase in the RAS/RAF/MAPK kinase pathway, which is integral to cellular division, survival, and metabolism. Two-thirds of pilocytic astrocytomas, a low-grade pediatric glioma, contain a translocation within the BRAF gene called KIAA1549:BRAF that causes an overactivation of the MEK/MAPK signaling cascade. In vitro and in vivo data support the use of MEK or mammalian target of rapamycin (mTOR) inhibitors in low-grade gliomas expressing this translocation. Additionally, 15-20% of high-grade pediatric gliomas express BRAF V600E, an activating mutation of the BRAF gene. Pre-clinical in vivo and in vitro data in BRAF V600E gliomas demonstrate dramatic cooperation between XRT and small molecule inhibitors of BRAF V600E. Another major signaling cascade that plays a role in pediatric glioma pathogenesis is the PI3-kinase (PI3K)/mTOR pathway, known to be upregulated in the majority of high- and low-grade pediatric gliomas. Dual PI3K/mTOR inhibitors are in clinical trials for adult high-grade gliomas and are poised to enter studies of pediatric tumors. Finally, many brain tumors express potent stimulators of angiogenesis that render them refractory to treatment. An analog of thalidomide, CC-5103 increases the secretion of critical cytokines of the tumor microenvironment, including IL-2, IFN-γ, TNF-α, and IL-10, and is currently being evaluated in clinical trials for the treatment of recurrent or refractory pediatric central nervous system tumors. In summary, several targeted inhibitors with radiation are currently under investigation in both translational bench research and early clinical trials. This review article summarizes the molecular rationale for, and the pre-clinical data supporting the combinations of these targeted agents with other anti-cancer agents and XRT in pediatric gliomas. In many cases, parallels are drawn to molecular mechanisms and targeted inhibitors of adult gliomas. We additionally discuss the potential mechanisms underlying the efficacy of these agents.

Phase I trial of capecitabine rapidly disintegrating tablets and concomitant radiation therapy in children with newly diagnosed brainstem gliomas and high-grade gliomas

BACKGROUND

We conducted a phase I study to estimate the maximum tolerated dose and describe the dose-limiting toxicities and pharmacokinetics of oral capecitabine rapidly disintegrating tablets given concurrently with radiation therapy to children with newly diagnosed brainstem or high-grade gliomas.

METHODS

Children 3-21 y with newly diagnosed intrinsic brainstem or high-grade gliomas were eligible for enrollment. The starting dose was 500 mg/m(2), given twice daily, with subsequent cohorts enrolled at 650 mg/m(2) and 850 mg/m(2) using a 3 + 3 phase I design. Children received capecitabine at the assigned dose daily for 9 wks starting from the first day of radiation therapy (RT). Following a 2-wk break, patients received 3 courses of capecitabine 1250 mg/m(2) twice daily for 14 days followed by a 7-day rest. Pharmacokinetic sampling was performed in consenting patients. Six additional patients with intrinsic brainstem gliomas were enrolled at the maximum tolerated dose to further characterize the pharmacokinetic and toxicity profiles.

RESULTS

Twenty-four patients were enrolled. Twenty were fully assessable for toxicity. Dose-limiting toxicities were palmar plantar erythroderma (grades 2 and 3) and elevation of alanine aminotransferase (grades 2 and 3). Systemic exposure to capecitabine and metabolites was similar to or slightly lower than predicted based on adult data.

CONCLUSIONS

Capecitabine with concurrent RT was generally well tolerated. The recommended phase II capecitabine dose when given with concurrent RT is 650 mg/m(2), administered twice daily. A phase II study to evaluate the efficacy of this regimen in children with intrinsic brainstem gliomas is in progress (PBTC-030).

Diffuse intrinsic pontine glioma: poised for progress

Diffuse intrinsic pontine gliomas (DIPGs) are amongst the most challenging tumors to treat. Surgery is not an option, the effects of radiation therapy are temporary, and no chemotherapeutic agent has demonstrated significant efficacy. Numerous clinical trials of new agents and novel therapeutic approaches have been performed over the course of several decades in efforts to improve the outcome of children with DIPG, yet without success. The diagnosis of DIPG is based on radiographic findings in the setting of a typical clinical presentation, and tissue is not routinely obtained as the standard of care. The paradigm for treating children with these tumors has been based on that for supratentorial high-grade gliomas in adults as the biology of these lesions were presumed to be similar. However, recent pivotal studies demonstrate that DIPGs appear to be their own entity. Simply identifying this fact releases a number of constraints and opens opportunities for biologic investigation of these lesions, setting the stage to move forward in identifying DIPG-specific treatments. This review will summarize the current state of knowledge of DIPG, discuss obstacles to therapy, and summarize results of recent biologic studies.

A phase II study of conventional radiation therapy and thalidomide for supratentorial, newly-diagnosed glioblastoma (RTOG 9806)

The Radiation Therapy Oncology Group (RTOG) initiated the single-arm, phase II study 9806 to determine the safety and efficacy of daily thalidomide with radiation therapy in patients with newly diagnosed glioblastoma. Patients were treated with thalidomide (200 mg daily) from day one of radiation therapy, increasing by 100-200 to 1,200 mg every 1-2 weeks until tumor progression or unacceptable toxicity. The median survival time (MST) of all 89 evaluable patients was 10 months. When compared with the historical database stratified by recursive partitioning analysis (RPA) class, this end point was not different [hazard ratio (HR) = 1.18; 95 % CI: 0.95-1.46; P = 0.93]. The MST of RPA class III and IV patients was 13.9 versus 12.5 months in controls (HR = 0.99; 95 % CI: 0.73-1.36; P = 0.48), and 4.3 versus 8.6 months in RPA class V controls (HR = 1.63, 95 % CI: 1.17-2.27; P = 0.99). In all, 34 % of patients discontinued thalidomide because of adverse events or refusal. The most common grade 3-4 toxicities were venous thrombosis, fatigue, skin reactions, encephalopathy, and neuropathy. In conclusion, thalidomide given simultaneously with radiation therapy was safe, but did not improve survival in patients with newly diagnosed glioblastoma.

Imaging biomarkers of angiogenesis and the microvascular environment in cerebral tumours

Conventional contrast-enhanced CT and MRI are now in routine clinical use for the diagnosis, treatment and monitoring of diseases in the brain. The presence of contrast enhancement is a proxy for the pathological changes that occur in the normally highly regulated brain vasculature and blood-brain barrier. With recognition of the limitations of these techniques, and a greater appreciation for the nuanced mechanisms of microvascular change in a variety of pathological processes, novel techniques are under investigation for their utility in further interrogating the microvasculature of the brain. This is particularly important in tumours, where the reliance on angiogenesis (new vessel formation) is crucial for tumour growth, and the resulting microvascular configuration and derangement has profound implications for diagnosis, treatment and monitoring. In addition, novel therapeutic approaches that seek to directly modify the microvasculature require more sensitive and specific biological markers of baseline tumour behaviour and response. The currently used imaging biomarkers of angiogenesis and brain tumour microvascular environment are reviewed.

Biologically targeted therapeutics in pediatric brain tumors

Pediatric brain tumors are often difficult to cure and involve significant morbidity when treated with traditional treatment modalities, including neurosurgery, conventional chemotherapy, and radiotherapy. During the past two decades, a clearer understanding of tumorigenesis, molecular growth pathways, and immune mechanisms in the pathogenesis of cancer has opened up promising avenues for therapy. Pediatric clinical trials with novel biologic agents are underway to treat various pediatric brain tumors, including high and low grade gliomas and embryonal tumors. As the therapeutic potential of these agents undergoes evaluation, their toxicity profiles are also becoming better understood. These agents have potentially better central nervous system penetration and lower toxicity profiles compared with conventional chemotherapy. In infants and younger children, biologic agents may prove to be of equal or greater efficacy compared with traditional chemotherapy and radiation therapy, and may reduce the deleterious side effects of traditional therapeutics on the developing brain. Molecular pathways implicated in pediatric brain tumors, agents that target these pathways, and current clinical trials are reviewed. Associated neurologic toxicities will be discussed subsequently. Considerable work is needed to establish the efficacy of these agents alone and in combination, but pediatric neurologists should be aware of these agents and their rationale.

Radiotherapy and "new" drugs-new side effects?

BACKGROUND AND PURPOSE

Targeted drugs have augmented the cancer treatment armamentarium. Based on the molecular specificity, it was initially believed that these drugs had significantly less side effects. However, currently it is accepted that all of these agents have their specific side effects. Based on the given multimodal approach, special emphasis has to be placed on putative interactions of conventional cytostatic drugs, targeted agents and other modalities. The interaction of targeted drugs with radiation harbours special risks, since the awareness for interactions and even synergistic toxicities is lacking. At present, only limited is data available regarding combinations of targeted drugs and radiotherapy. This review gives an overview on the current knowledge on such combined treatments.

MATERIALS AND METHODS

Using the following MESH headings and combinations of these terms pubmed database was searched: Radiotherapy AND cetuximab/trastuzumab/panitumumab/nimotuzumab, bevacizumab, sunitinib/sorafenib/lapatinib/gefitinib/erlotinib/sirolimus, thalidomide/lenalidomide as well as erythropoietin. For citation crosscheck the ISI web of science database was used employing the same search terms.

RESULTS

Several classes of targeted substances may be distinguished: Small molecules including kinase inhibitors and specific inhibitors, antibodies, and anti-angiogenic agents. Combination of these agents with radiotherapy may lead to specific toxicities or negatively influence the efficacy of RT. Though there is only little information on the interaction of molecular targeted radiation and radiotherapy in clinical settings, several critical incidents are reported.

CONCLUSIONS

The addition of molecular targeted drugs to conventional radiotherapy outside of approved regimens or clinical trials warrants a careful consideration especially when used in conjunction in hypo-fractionated regimens. Clinical trials are urgently needed in order to address the open question in regard to efficacy, early and late toxicity.

Treatment of high-grade glioma in children and adolescents

Pediatric high-grade gliomas (HGGs)--including glioblastoma multiforme, anaplastic astrocytoma, and diffuse intrinsic pontine glioma--are difficult to treat and are associated with an extremely poor prognosis. There are no effective chemotherapeutic regimens for the treatment of pediatric HGG, but many new treatment options are in active investigation. There are crucial molecular differences between adult and pediatric HGG such that results from adult clinical trials cannot simply be extrapolated to children. Molecular markers overexpressed in pediatric HGG include PDGFRα and P53. Amplification of EGFR is observed, but to a lesser degree than in adult HGG. Potential molecular targets and new therapies in development for pediatric HGG are described in this review. Research into bevacizumab in pediatric HGG indicates that its activity is less than that observed in adult HGG. Similarly, tipifarnib was found to have minimal activity in pediatric HGG, whereas gefitinib has shown greater effects. After promising phase I findings in children with primary CNS tumors, the integrin inhibitor cilengitide is being investigated in a phase II trial in pediatric HGG. Studies are also ongoing in pediatric HGG with 2 EGFR inhibitors: cetuximab and nimotuzumab. Other novel treatment modalities under investigation include dendritic cell-based vaccinations, boron neutron capture therapy, and telomerase inhibition. While the results of these trials are keenly awaited, the current belief is that multimodal therapy holds the greatest promise. Research efforts should be directed toward building multitherapeutic regimens that are well tolerated and that offer the greatest antitumor activity in the setting of pediatric HGG.

Anti-angiogenic therapy in glioma

There has been great interest in developing anti-angiogenic therapies for the treatment of patients with high-grade gliomas. In fact, some anti-angiogenic agents are now routinely used for the treatment of patients with glioblastoma. However, the use of these agents is largely based on trials which indicate an initial radiographic response, while it remains unclear whether any anti-angiogenic therapies tested to date have improved the overall survival of patients with malignant glial tumours. This manuscript reviews the landscape of anti-angiogenic therapy in glioma, with a focus on GBM, and demonstrates that further innovation is needed to determine the true utility of anti-angiogenic therapy.

Temozolomide in the treatment of children with newly diagnosed diffuse intrinsic pontine gliomas: a report from the Children's Oncology Group

An open-label phase II study (ACNS0126) testing the efficacy of chemoradiotherapy with temozolomide (TMZ) followed by adjuvant TMZ was conducted by the Children's Oncology Group. During the period from July 6, 2004 through September 6, 2005, 63 children with newly diagnosed diffuse intrinsic pontine glioma (DIPG) were enrolled in the study. All patients received TMZ at a dosage of 90 mg/m(2)/day for 42 days to a dose of 59.4 Gy. Four weeks following irradiation, TMZ was given at a dosage of 200 mg/m(2)/day for 5 days every 28 days, for a total of 10 cycles. The primary objective of the statistical analysis was to determine whether the current treatment produced a 1-year event-free survival (EFS) rate higher than the historical baseline of 21.9% observed in CCG-9941. The mean 1-year EFS (± standard deviation) was 14% ± 4.5%, compared with 21.9% ± 5% for CCG-9941. The P value of the test of comparison of 1-year EFS, based on a 1-sided, 1-sample test of proportions, was .96. There was no evidence that temozolomide produced a 1-year EFS rate higher than 21.9%. The mean 1-year OS (± standard deviation) was 40% ± 6.5%, compared with 32% ± 6% for CCG-9941. The median time to death was 9.6 months. Chemoradiotherapy with TMZ followed by adjuvant TMZ is not more effective than previously reported regimens for the treatment of children with DIPG.

MRI as a central component of clinical trials analysis in brainstem glioma: a report from the Pediatric Brain Tumor Consortium (PBTC)

We report MRI findings from 2 pediatric clinical trials of diffuse intrinsic brainstem glioma (BSG) incorporating concurrent radiation therapy (RT) with molecularly targeted agents (gefitinib and tipifarnib). We determined associations of MRI variables with progression-free survival and overall survival and investigated effects of treatment on these variables. MRI (including diffusion and perfusion) was done before treatment, every 8 weeks (first year), every 12 weeks (thereafter), and at the end of treatment or disease progression. Reduced tumor volume (P < .0001) and tumor diffusion values (P <.0001) were apparent on the first post-RT/drug studies. Decreases in tumor volume correlated with pre-RT volume (P < .0001) and pre-RT diffusion values (P < .0001); larger decreases were noted for tumors with higher volumes and diffusion values. Patients with larger pre-RT tumors had longer progression-free survival (P < .0001). Patients with ≥ 25% decrease in tumor volume and diffusion values after RT had longer progression-free survival (P = .028) and overall survival (P = .0009). Enhancement at baseline and over time was significantly associated with shorter survival. Tumor diffusion values with baseline enhancement were significantly lower than those without (P = .0002). RT of BSG is associated with decreased tumor volume and intralesional diffusion values; patients with ≥ 25% decrease in values post-RT had relatively longer survival intervals, apparently providing an early imaging-based surrogate for relative outcomes. Patients with larger tumors and greater decreases in tumor volume and diffusion values had longer survival intervals. Tumor enhancement was associated with shorter survival, lower tumor diffusion values (increased cellularity), and a smaller drop in diffusion values after RT (P = .006). These associations justify continued investigation in other large clinical trials of brainstem glioma patients.

New anti-angiogenic strategies in pediatric solid malignancies: agents and biomarkers of a near future

IMPORTANCE OF THE FIELD

Antiangiogenic strategies are affording considerable interest and have become a major milestone in therapeutics of various adult cancers. However, progress has been slow to expand such therapies to patients with pediatric solid malignancies.

AREAS COVERED IN THIS REVIEW

This review discusses the principal pathways for angiogenesis in pediatric solid malignancies and summarizes recent preclinical and clinical data on antiangiogenesis strategies in these tumors.

WHAT THE READER WILL GAIN

The reader will gain state-of-the-art knowledge in the current advancements of antiangiogenic therapies in pediatric clinical trials in regard to supporting preclinical data, and in the status of potential biomarkers investigated for monitoring angiogenesis inhibitors. Mechanisms of resistance to antiangiogenic therapy will also be discussed. Finally, we describe our experience in the monitoring of circulating endothelial cells and progenitors and their potential role as biomarkers of metastatic disease and resistance to antiangiogenic therapies.

TAKE HOME MESSAGE

Evaluation and development of antiangiogenesis protocols are starting and represent a crucial step in the management of pediatric solid malignancies today. Emphasis should be placed on the development of proper surrogate markers to monitor antiangiogenic activity and on the possible long-term effects of these therapies in a pediatric population.

A prospective study of temozolomide plus thalidomide during and after radiation therapy for pediatric diffuse pontine gliomas: preliminary results of the Korean Society for Pediatric Neuro-Oncology study

This prospective study was performed to determine the efficacy and safety of temozolomide (TMZ) plus thalidomide during and after radiation therapy (RT) in pediatric patients with newly diagnosed diffuse pontine glioma (DPG). Seventeen patients with pediatric DPG were enrolled between November 2004 and March 2008. The median age was eight years (range, 3-16 years); seven patients were male and ten were female. With the exception of one glioblastoma case, which was diagnosed via open biopsy, all diagnoses were established using neuroradiological studies. The authors used the Korean Society for Pediatric Neuro-Oncology (KSPNO)-A053 protocol. The mean follow-up period was 12 months (range, 8.5-25 months). Five patients were withdrawn from the study. The rates of response to treatment and survival were analyzed in 12 patients. Ten out of the 12 patients showed a partial response (PR), whereas one patient exhibited stable disease (SD) and another patient had progressive disease (PD). The tumor control rate was 92% (11/12) and the response rate was 83% (10/12). The median progression-free survival (PFS) of the 12 patients was 7.2 months (95% confidence interval (CI), 3.6-10.7). Six-month and twelve-month PFS were 58.3 and 16.7%, respectively. Overall survival (OS) was 12.7 months (95% CI, 10.4-15.1). One and two-year survival were 58.3 and 25%, respectively. The main adverse effect was hematological toxicity, with four patients exhibiting grade 3 or 4 toxicity. All patients tolerated the regimen well enough to continue the adjuvant chemotherapy. No Pneumocystis jiroveci pneumonia was noted. The TMZ plus thalidomide regimen was safe and tolerated well enough to be administered on an outpatient basis. Larger studies are required to demonstrate the efficacy of this regimen.

Phase I study of vandetanib with radiotherapy and temozolomide for newly diagnosed glioblastoma

PURPOSE

Increasing evidence has suggested that angiogenesis inhibition might potentiate the effects of radiotherapy and chemotherapy in patients with glioblastoma (GBM). In addition, epidermal growth factor receptor inhibition might be of therapeutic benefit, because the epidermal growth factor receptor is upregulated in GBM and contributes to radiation resistance. We conducted a Phase I study of vandetanib, an inhibitor of vascular endothelial growth factor receptor 2 and epidermal growth factor receptor, in patients with newly diagnosed GBM combined with RT and temozolomide (TMZ).

METHODS AND MATERIALS

A total of 13 GBM patients were treated with vandetanib, radiotherapy, and concurrent and adjuvant TMZ, using a standard "3 + 3" dose escalation. The maximal tolerated dose was defined as the dose with <1 of 6 dose-limiting toxicities during the first 12 weeks of therapy. The eligible patients were adults with newly diagnosed GBM, Karnofsky performance status of >or=60, normal organ function, who were not taking enzyme-inducing antiepileptic drugs.

RESULTS

Of the 13 patients, 6 were treated with vandetanib at a dose of 200mg daily. Of the 6 patients, 3 developed dose-limiting toxicities within the first 12 weeks, including gastrointestinal hemorrhage and thrombocytopenia in 1 patient, neutropenia in 1 patient, and diverticulitis with gastrointestinal perforation in 1 patient. The other 7 patients were treated with 100 mg daily, with no dose-limiting toxicities observed, establishing this dose as the maximal tolerated dose combined with TMZ and RT.

CONCLUSION

Vandetanib can be safely combined with RT and TMZ in GBM patients. A Phase II study in which patients are randomized to vandetanib 100 mg daily with RT and TMZ or RT and TMZ alone is underway.

Glioblastoma multiforme in a patient with chronic granulomatous disease treated with subtotal resection, radiation, and thalidomide: case report of a long-term survivor

We report on a child with chronic granulomatous disease who at the age of 13 years was diagnosed with glioblastoma multiforme of the left thalamus. Therapy included subtotal resection, radiation to the tumor bed (60 Gy), and concomitant chemotherapy with daily thalidomide (250 mg/m2), both during radiation and for 5 years thereafter. Currently, she is 9 years from diagnosis and has no evidence of disease. Therapy with thalidomide did not increase her infection complications and provided excellent quality of life. This is the first report of glioblastoma multiforme in a patient with chronic granulomatous disease treated with surgery, radiation, and thalidomide who is a long-term survivor.

[Proton magnetic resonance spectroscopic imaging and other types of metabolic imaging for radiotherapy planning in adult and pediatric high-grade gliomas]

Radiation therapy improves survival in high-grade gliomas but most patients relapse and usually within radiation fields. This may be due to uncertainties in target delineation and difficulties in identifying radioresistant regions for dose escalation. The use of T1 and T2-weighted magnetic resonance imaging (MRI) coregistration on the planning CT improves the target volume definition but magnetic resonance spectroscopic imaging (MRSI) and other types of metabolic and functional imaging (perfusion MRI, diffusion-weighted MRI, positron emission tomography (PET) imaging) may give useful additional information for target delineation. This article focuses on the potential of each imaging modality: assessment of response to treatment, detection of abnormalities not seen on MRI, predictive value for the site of local relapse. The incorporation of such techniques may improve target volume definition.

Brainstem gliomas in children and adults

PURPOSE OF REVIEW

The purpose of this review is to determine if recent advances in diagnostic and treatment modalities result in improvement in the pattern of care of brainstem gliomas.

RECENT FINDINGS

New MRI techniques may contribute to differential diagnosis and aid neurosurgeons in removing resectable brainstem tumors. A better radiological analysis of these heterogeneous tumors improves their classification and helps to better distinguish prognosis subgroups. However, biopsy remains indicated in many contrast enhancing brainstem masses in adults because of the great variety of differential diagnosis.

SUMMARY

Diffuse brainstem glioma is the most common subtype of brainstem tumor and remains a devastating malignancy in children. Conventional radiotherapy is the standard of care and chemotherapy has been disappointing to date. Given the lack of efficacy of conventional drugs, a better understanding of the biology of this tumor is the key to more targeted therapy.

Treatment of diffuse intrinsic brainstem gliomas: failed approaches and future strategies

Diffuse intrinsic pontine gliomas constitute ~ 60-75% of tumors found within the pediatric brainstem. These malignant lesions present with rapidly progressive symptoms such as cranial nerve, long tract, or cerebellar dysfunctions. Magnetic resonance imaging is usually sufficient to establish the diagnosis and obviates the need for surgical biopsy in most cases. The prognosis of the disease is dismal, and the median survival is < 12 months. Resection is not a viable option. Standard therapy involves radiotherapy, which produces transient neurological improvement with a progression-free survival benefit, but provides no improvement in overall survival. Clinical trials have been conducted to assess the efficacy of chemotherapeutic and biological agents in the treatment of diffuse pontine gliomas. In this review, the authors discuss recent studies in which systemic therapy was administered prior to, concomitantly with, or after radiotherapy. For future perspective, the discussion includes a rationale for stereotactic biopsies as well as possible therapeutic options of local chemotherapy in these lesions.

Diffuse brainstem gliomas in children: should we or shouldn't we biopsy?

The decision to biopsy diffuse pontine gliomas in children remains controversial. There have been many publications over the last 30 years aiming to address this issue. The prognosis for these patients remains extremely poor regardless of treatment and many authors advocate that biopsy carries significant risk for little or no clinical benefit. However, with an increasing knowledge of tumour biology and genetics there is the potential for specific treatments tailored for individual tumours based on their biological or genetic characteristics. The progress of such science in the first instance requires histological diagnosis as part of well conducted clinical trials, then, when treatments have been developed, biopsy samples will be needed to identify the tumours that may respond to such treatments. The authors believe that there is an increasing need for performing a biopsy of these lesions.

Feasibility of using bevacizumab with radiation therapy and temozolomide in newly diagnosed high-grade glioma

INTRODUCTION

Bevacizumab, a monoclonal antibody against vascular endothelial growth factor (VEGF), has shown promise in the treatment of patients with recurrent high-grade glioma. The purpose of this study is to test the feasibility of using bevacizumab with chemoradiation in the primary management of high-grade glioma.

METHODS AND MATERIALS

Fifteen patients with high-grade glioma were treated with involved field radiation therapy to a dose of 59.4 Gy at 1.8 Gy/fraction with bevacizumab 10 mg/kg on Days 14 and 28 and temozolomide 75 mg/m(2). Subsequently, bevacizumab 10 mg/kg was continued every 2 weeks with temozolomide 150 mg/m(2) for 12 months. Changes in relative cerebral blood volume, perfusion-permeability index, and tumor volume measurement were measured to assess the therapeutic response. Immunohistochemistry for phosphorylated VEGF receptor 2 (pVEGFR2) was performed.

RESULTS

Thirteen patients (86.6%) completed the planned bevacizumab and chemoradiation therapy. Four Grade III/IV nonhematologic toxicities were seen. Radiographic responses were noted in 13 of 14 assessable patients (92.8%). The pVEGFR2 staining was seen in 7 of 8 patients (87.5%) at the time of initial diagnosis. Six patients have experienced relapse, 3 at the primary site and 3 as diffuse disease. One patient showed loss of pVEGFR2 expression at relapse. One-year progression-free survival and overall survival rates were 59.3% and 86.7%, respectively.

CONCLUSION

Use of antiangiogenic therapy with radiation and temozolomide in the primary management of high-grade glioma is feasible. Perfusion imaging with relative cerebral blood volume, perfusion-permeability index, and pVEGFR2 expression may be used as a potential predictor of therapeutic response. Toxicities and patterns of relapse need to be monitored closely.

Clinical biomarkers of angiogenesis inhibition

INTRODUCTION

An expanding understanding of the importance of angiogenesis in oncology and the development of numerous angiogenesis inhibitors are driving the search for biomarkers of angiogenesis. We review currently available candidate biomarkers and surrogate markers of anti-angiogenic agent effect.

DISCUSSION

A number of invasive, minimally invasive, and non-invasive tools are described with their potential benefits and limitations. Diverse markers can evaluate tumor tissue or biological fluids, or specialized imaging modalities.

CONCLUSIONS

The inclusion of these markers into clinical trials may provide insight into appropriate dosing for desired biological effects, appropriate timing of additional therapy, prediction of individual response to an agent, insight into the interaction of chemotherapy and radiation following exposure to these agents, and perhaps most importantly, a better understanding of the complex nature of angiogenesis in human tumors. While many markers have potential for clinical use, it is not yet clear which marker or combination of markers will prove most useful.

Recent development in chemotherapy of paediatric brain tumours

PURPOSE OF REVIEW

Chemotherapy has gained a larger importance in the management of brain tumours, especially in children.

RECENT FINDINGS

Converging results were presented in 2005 by the German, French and North-American cooperative groups indicating that a subgroup of young children with medulloblastoma (i.e. those with desmoplastic histology) could be cured with chemotherapy only strategies. The usefulness of high-dose chemotherapy followed by stem-cell transplant was shown not only as salvage strategy but also upfront in high-risk patients with medulloblastoma. Diffuse pontine glioma remains a devastating disease despite numerous attempts to improve on the standard radiotherapy. Targeted therapies have entered the paediatric neuro-oncology field as well.

SUMMARY

In the most frequent paediatric brain tumors (medulloblastoma and low grade gliomas), the improvements have been impressive in recent years. These patients still await new targeted therapies to lower the burden of treatments and their related side-effects. Most of the brain tumours, however, are rare and the development of specific protocols too slow. Likely, they may have very specific biologic abnormalities that could be efficiently targeted in the near future.

Treatment of newly diagnosed diffuse brain stem gliomas in children: in search of the holy grail

Diffuse brain stem glioma is the most devastating of pediatric malignancies. Virtually all children with this disease die within 1-2 years of diagnosis. After three decades of exhaustive research, the key to controlling this malignancy still eludes us. Attempts to improve survival using radiation, chemotherapy and biologic agents have yet to culminate in meaningful advances. Recent advances in molecular biology have led to the development of more targeted therapies, which are now being introduced in clinical trials for children with brain stem glioma. As our understanding of the biology of this disease improves, so too will our ability to target it more effectively. Real strides in improving the lives of children with brain stem glioma may finally be within our grasp.

Congenital glioblastoma: a clinicopathologic and genetic analysis

Congenital central nervous system (CNS) tumors are uncommon, accounting for 1% of all childhood brain tumors. They present clinically either at birth or within the first 3 months. Glioblastoma (GBM) only rarely occurs congenitally and has not been fully characterized. We examined clinicopathologic features and genetic alterations of six congenital GBMs. Tumors were seen by neuroimaging as large, complex cerebral hemispheric masses. All showed classic GBM histopathology, including diffuse infiltration, dense cellularity, GFAP-positivity, high mitotic activity, endothelial proliferation and pseudopalisading necrosis. Neurosurgical procedures and adjuvant therapies varied. Survivals ranged from 4 days to 7.5 years; two of the three long-term survivors received chemotherapy, whereas the three short-term survivors did not. Paraffin-embedded tissue sections were used for FISH analysis of EGFR, chromosomes 9p21 (p16/CDKN2A) and 10q ( PTEN/DMBT1); sequencing of PTEN and TP53; and immunohistochemistry for EGFR and p53. We uncovered 10q deletions in two cases. No EGFR amplifications, 9p21 deletions, or mutations of TP53 or PTEN were noted; however, nuclear p53 immunoreactivity was strong in 5/6 cases. Tumors were either minimally immunoreactive (n = 3) or negative (n = 3) for EGFR. We conclude that congenital GBMs show highly variable survivals. They are genetically distinct from their adult counterparts and show a low frequency of known genetic alterations. Nonetheless, the strong nuclear expression of p53 in these and other pediatric GBMs could indicate that p53 dysregulation is important to tumorigenesis.