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

Angiogenesis in gliomas

Angiogenesis, the sprouting of new blood vessels from preexisting blood vessels, is a hallmark of glioma progression. Malignant gliomas are among the most lethal tumors with a very dismal prognosis, despite advances in standard therapy, including surgery, radiation, and chemotherapy. The median survival of patients with malignant gliomas has changed little in the last few years and is still measured in months. In an attempt to develop new therapeutic strategies and identify the molecular mechanism involved in glioma growth and progression, there has been extraordinary scientific interest in the past 2 decades in angiogenic responses associated with gliomas. This chapter focuses on the molecular mechanism of glioma angiogenesis and summarizes some of the therapeutic approaches based on antiangiogenesis.

Genetic associations with thalidomide mediated venous thrombotic events in myeloma identified using targeted genotyping

A venous thromboembolism (VTE) with the subsequent risk of pulmonary embolism is a major concern in the treatment of patients with multiple myeloma with thalidomide. The susceptibility to developing a VTE in response to thalidomide therapy is likely to be influenced by both genetic and environmental factors. To test genetic variation associated with treatment related VTE in patient peripheral blood DNA, we used a custom-built molecular inversion probe (MIP)-based single nucleotide polymorphism (SNP) chip containing 3404 SNPs. SNPs on the chip were selected in "functional regions" within 964 genes spanning 67 molecular pathways thought to be involved in the pathogenesis, treatment response, and side effects associated with myeloma therapy. Patients and controls were taken from 3 large clinical trials: Medical Research Council (MRC) Myeloma IX, Hovon-50, and Eastern Cooperative Oncology Group (ECOG) EA100, which compared conventional treatments with thalidomide in patients with myeloma. Our analysis showed that the set of SNPs associated with thalidomide-related VTE were enriched in genes and pathways important in drug transport/metabolism, DNA repair, and cytokine balance. The effects of the SNPs associated with thalidomide-related VTE may be functional at the level of the tumor cell, the tumor-related microenvironment, and the endothelium. The clinical trials described in this paper have been registered as follows: MRC Myeloma IX: ISRCTN68454111; Hovon-50: NCT00028886; and ECOG EA100: NCT00033332.

A multi-institutional phase II study on second-line Fotemustine chemotherapy in recurrent glioblastoma

The present study aims to assess the feasibility and the effectiveness of a second-line Fotemustine chemotherapy in patients with recurrent Glioblastoma after standard primary treatment. Between 2005 and 2007, 50 patients with relapsed malignant glioma (median age=56.8 years; median KPS=90) underwent a second-line chemotherapy with Fotemustine. Selected patients were previously treated with a standard 60 Gy Radiotherapy course and Temozolomide Chemotherapy. Patients were stratified into classes according to the prognostic Recursive Partition Analysis. Endpoints of the study were Progression Free Survival at 6 months, duration of Objective Response and Stabilization, Overall Survival and toxicity. At analysis, 36 patients were dead and 14 were alive. Median follow-up from primary diagnosis was 26.6 months. The Efficacy control of the disease was 62%. PFS was 6.1 months; PFS-6 was 52% and median overall survival from primary diagnosis was 24.5 months, with few manageable haematological toxicities. Fotemustine was safe and effective as second-line chemotherapy in recurrent glioblastoma.

A phase II study of thalidomide and irinotecan for treatment of glioblastoma multiforme

PURPOSE

Irinotecan is a cytotoxic agent with activity against gliomas. Thalidomide, an antiangiogenic agent, may play a role in the treatment of glioblastoma multiforme (GBM). To evaluate the combination of thalidomide and irinotecan, we conducted a phase II trial in adults with newly-diagnosed or recurrent GBM.

PATIENTS AND METHODS

Thalidomide was given at a dose of 100 mg/day, followed by dose escalation every 2 weeks by 100 mg/day to a target of 400 mg/day. Irinotecan was administered on day 1 of each 3 week cycle. Irinotecan dose was 700 mg/m(2) for patients taking enzyme-inducing anticonvulsants and 350 mg/m(2) for all others. The primary endpoint was tumor response, assessed by MRI. Secondary endpoints were toxicity, progression-free survival, and overall survival.

RESULTS

Twenty-six patients with a median age of 55 years were enrolled, with fourteen evaluable for the primary outcome, although all patients were included for secondary endpoints. One patient (7%) exhibited a partial response after twelve cycles, and eleven patients (79%) had stable disease. The intention to treat group with recurrent disease included 16 patients who had a 6-month PFS of 19% (95% CI: 4-46%) and with newly-diagnosed disease included 10 patients who had a 6-month PFS of 40% (95% CI: 12-74%). Gastrointestinal (GI) toxicity was mild, but six patients (23%) experienced a venous thromboembolic complication. Two patients had Grade 4 treatment-related serious adverse events that required hospitalization. There were no treatment-related deaths.

CONCLUSION

The combination of irinotecan and thalidomide has limited activity against GBM. Mild GI toxicity was observed, but venous thromboembolic complications were common.

Antiangiogenic therapy in brain tumors

Angiogenesis, the recruitment of new blood vessels, is an essential component of tumor progression. Malignant brain tumors are highly vascularized and their growth is angiogenesis-dependent. As such, inhibition of the sprouting of new capillaries from pre-existing blood vessels is one of the most promising antiglioma therapeutic approaches. Numerous classes of molecules have been implicated in regulating angiogenesis and, thus, novel agents that target and counteract angiogenesis are now being developed. The therapeutic trials of a number of angiogenesis inhibitors as antiglioma drugs are currently under intense investigation. Preliminary studies of angiogenic blockade in glioblastoma have been promising and several clinical trials are now underway to develop optimum treatment strategies for antiangiogenic agents. This review will cover state-of-the-art antiangiogenic targets for brain tumor treatment and discuss future challenges. An increased understanding of the angiogenic process, the diversity of its inducers and mediators, appropriate drug schedules and the use of these agents with other modalities may lead to radically new treatment regimens to achieve maximal efficacy.

Therapeutic application of noncytotoxic molecular targeted therapy in gliomas: growth factor receptors and angiogenesis inhibitors

Growth factor receptors and angiogenesis play major roles in the oncogenesis of gliomas. Over the last several years, several noncytotoxic molecular targeted therapies have been developed against growth factor receptors and tumor angiogenesis. In gliomas, two main anti-growth factor receptor strategies have been evaluated in phase I/II clinical trials: (a) small molecule tyrosine kinase inhibitors (TKIs) and (b) monoclonal antibodies that target growth factors or growth factor receptors other than vascular endothelial growth factor (VEGF). Up to now, few glioma patients have responded to small TKIs (0%-14%) or monoclonal antibodies (three case reports) delivered as a single agent. Greater doses, combined therapies, as well as the identification of molecular biomarkers predictive of response and resistance are important in order to optimize drug delivery and improve efficacy. Antiangiogenic therapies are promising for the treatment of gliomas. Thalidomide and metronomic chemotherapy were the first antiangiogenic strategies evaluated, but they have shown only modest activity. Recent studies of bevacizumab, an anti-VEGF antibody, and irinotecan, a topoisomerase I inhibitor, have demonstrated a high response rate, suggesting that targeted antiangiogenic therapies may play a significant role in the management of high-grade gliomas in the future. However, the toxicity profiles of these agents are not fully defined and the radiological evaluation of possible tumor response is challenging. Clinical evaluation of several VEGF receptor TKIs is currently ongoing; one of these inhibitors, cediranib, has already demonstrated interesting activity as a single agent. The integrin inhibitor cilengitide represents another promising strategy.

New molecular targets in angiogenic vessels of glioblastoma tumours

Antiangiogenesis approaches have the potential to be particularly effective in the treatment of glioblastoma tumours. These tumours exhibit extremely high levels of neovascularisation, which may contribute to their extremely aggressive behaviour, not only by providing oxygenation and nutrition, but also by establishing a leaky vasculature that lacks a blood-brain barrier. This leaky vasculature enables migration of tumour cells, as well as the build up of fluid, which exacerbates tissue damage due to increased intracranial pressure. Here, we discuss the considerable progress that has been made in the identification of the pro- and antiangiogenic factors produced by glioblastoma tumours and the effects of these molecules in animal models of the disease. The safety and efficacy of some of these approaches have now been demonstrated in clinical trials. However, the ability of tumours to overcome these therapies and to re-establish angiogenesis requires further clinical research regarding potential multimodality therapies, as well as basic research into the regulation of angiogenesis by as yet unidentified factors. Optimisation of noninvasive procedures for monitoring of angiogenesis would greatly facilitate such research.

A Single Institution's Experience with Bevacizumab in Combination with Cytotoxic Chemotherapy in Progressive Malignant Glioma

BACKGROUND

Bevacizumab and irinotecan may represent one of the most active treatments in progressive malignant glioma. Limited published experience with bevacizumab in patients with CNS tumors raises concerns regarding toxicity, particularly in regards to hemorrhage and thromboembolism.

METHODS

We retrospectively reviewed 36 patients with progressive malignant glioma after prior resection, chemotherapy and radiation who were treated with bevacizumab at our institution. Patients were evaluated for bevacizumab-related adverse events, time to treatment failure (TTF) and overall survival (OS). Two patients who progressed or died prior to completion of 4 cycles of therapy were analyzed for adverse events only.

RESULTS

Patients were treated with bevacizumab alone (1), bevacizumab plus irinotecan (31), or bevacizumab plus carboplatin (4). In 34 patients who received >4 cycles of bevacizumab, median TTF and OS were 16 and 32 weeks, respectively. Toxicities included 1 arterial thrombosis, 4 venous thromboses, and 3 clinically significant CNS hemorrhages.

CONCLUSION

Overall, our results confirm the efficacy and safety of bevacizumab in combination with chemotherapy in patients with progressive malignant glioma. Although the TTF and OS were less than previously reported with the combination of bevacizumab and irinotecan, this was an unselected patient population with 50% of patients having received >1 prior chemotherapy regimen.

Phase II study of temozolomide, thalidomide, and celecoxib for newly diagnosed glioblastoma in adults

We conducted a phase II study of the combination of temozolomide and angiogenesis inhibitors for treating adult patients with newly diagnosed glioblastoma. Patients who had stable disease following standard radiation therapy received temozolomide for 5 days in 28-day cycles, in combination with daily thalidomide and celecoxib. Patients were treated until tumor progression or development of unacceptable toxicity. Four-month progression-free survival (PFS) from study enrollment was the primary end point, and overall survival (OS) was the secondary end point. In addition, we sought to correlate response with O(6)-methylguanine-DNA methyltransferase promoter methylation status and serum levels of angiogenic peptides. Fifty patients with glioblastoma were enrolled (18 women, 32 men). Median age was 54 years (range, 29-78) and median KPS score was 90 (range, 70-100). From study enrollment, median PFS was 5.9 months (95% confidence interval [CI]: 4.2-8.0) and 4-month PFS was 63% (95% CI: 46%-75%). Median OS was 12.6 months (95% CI: 8.5-16.4) and 1-year OS was 47%. Of the 47 patients evaluable for best response, none had a complete response, five (11%) had partial response, four (9%) had minor response, 22 (47%) had stable disease, and 16 (34%) had progressive disease. Analysis of serial serum samples obtained from 47 patients for four angiogenic peptides failed to show a significant correlation with response or survival for three of the peptides; higher vascular endothelial growth factor levels showed a trend toward correlation with decreased OS (p=0.07) and PFS (p=0.09). The addition of celecoxib and thalidomide to adjuvant temozolomide was well tolerated but did not meet the primary end point of improvement of 4-month PFS from study enrollment.

Angiogenesis and gliomas: current issues and development of surrogate markers

Despite significant improvements, current therapies have yet to cure infiltrative gliomas. Glioma progression is strongly dependent on the development of a new vascular network that occurs primarily by angiogenesis. Hypoxia and genetic anomalies within a glioma trigger the angiogenic switch, thus upregulating angiogenic factors and downregulating antiangiogenic factors. The main factors indicative of angiogenesis are now well known, and more recently, differences based on grade and subtype have been reported. New data also indicate a potential role for postnatal vasculogenesis with bone marrow endothelial progenitors in addition to angiogenesis in tumor vascular development. All of these factors may have therapeutic implications. Antiangiogenic therapies are presently being developed; more than 80 trials are ongoing. Initial results indicate that epidermal growth factor receptor inhibitors, anti-metalloproteases, and thalidomide do not demonstrate strong anti-tumor activity. Thus, antiangiogenic agents combined with conventional therapies and second-generation antiangiogenic drugs for targeting multiple molecular pathways are presently being tested. Clinical experience also demonstrates the failure of conventional imaging to monitor these new approaches accurately. New advances in the design of surrogate markers for angiogenesis have been reported for both magnetic resonance and molecular imaging techniques. This article summarizes the mechanisms of the angiogenic switch based on tumor grade and subtype, reviews completed and ongoing clinical trials, and details the present and the future of surrogate markers for angiogenesis in gliomas.

A prospective randomized trial of thalidomide with topotecan compared with topotecan alone in women with recurrent epithelial ovarian carcinoma

BACKGROUND

Thalidomide is an antiangiogenic agent with immune modulating potential. The objective of this study was to determine response rates among women who were treated for recurrent ovarian cancer using topotecan with or without thalidomide.

METHODS

Women were enrolled in this multicenter, prospective, randomized phase 2 trial between April 2001 and July 2005. Eligible patients had recurrent epithelial ovarian carcinoma with measurable disease or elevated CA 125 values. Patients had received prior platinum-based chemotherapy. Treatment arms received topotecan at a dose of 1.25 mg/m(2) on Days 1 through 5 of a 21-day cycle with or without thalidomide starting at a dose of 200 mg per day and then increasing the dose as tolerated. Toxicity was graded according to the National Cancer Institute Common Toxicity Criteria. The chi-square test was used to assess differences in response and toxicity, and the log-rank test was used to compare Kaplan-Meier survival curves.

RESULTS

The analysis included 69 women (39 women in the control arm and 30 women in the thalidomide arm). Known prognostic factors, including platinum sensitivity, were represented equally in each arm. The median thalidomide dose was 200 mg per day. The overall response rate in the control arm was 21% (complete response [CR] rate, 18%; partial response [PR] rate, 3%) compared with 47% in the thalidomide arm (CR rate, 30%; PR rate, 17%) (P= .03). The median progression-free survival for the control arm was 4 months compared with 6 months in the thalidomide arm (P= .02). The median overall survival was 15 months in the control arm and 19 months in the thalidomide arm (P= .67). Toxicities were similar between groups.

CONCLUSIONS

The addition of thalidomide to topotecan for the treatment of recurrent ovarian cancer appears to improve response rates, and the authors believe that it warrants study through larger phase 3 trials.

Inhibition of angiogenesis and invasion in malignant gliomas

Malignant gliomas confer a dismal prognosis. As the molecular events that underlie tumor angiogenesis are elucidated, angiogenesis inhibition is emerging as a promising therapy for recurrent and newly diagnosed tumors. Data from animal studies suggest that angiogenesis inhibition may promote an invasive phenotype in tumor cells. This may represent an important mechanism of resistance to antiangiogenic therapies. Recent studies have begun to clarify the mechanisms by which glioma cells detach from the tumor mass, remodel the extracellular matrix and infiltrate normal brain. An array of potential therapeutic targets exists. Combination therapy with antiangiogenic and novel anti-invasion agents is a promising approach that may produce a synergistic antitumor effect and a survival benefit for patients with these devastating tumors.

Targeted therapy for malignant gliomas

The identification of markers that are associated with tumour but not normal tissue has allowed the development of highly-specific targeted therapies. Monoclonal antibodies, either alone or linked to radioisotopes or toxins, have provided a powerful tool for research, as well as the basis for promising therapeutic agents with less side effects than standard radiotherapy or chemotherapy. A new class of drugs, the tyrosine kinase inhibitors, which interfere with the function of key molecules in cancer-promoting pathways, have had a dramatic effect in haematological malignancy and are being trialled in solid tumours, including glioma. Although the problem of achieving specific, high-level delivery of these various agents to tumours in the brain remains a major issue, encouraging early results with some targeted agents support the attractive theoretical principles of this new paradigm. Further work to identify new molecular targets and to develop agents exploiting them, is needed, as well as confirmation of their safety and efficacy by clinical trials.

Phase II trial of thalidomide with chemotherapy and as maintenance therapy for patients with poor prognosis small-cell lung cancer

BACKGROUND

Despite the high response rates achieved following standard chemotherapy for small-cell lung cancer (SCLC), the majority of patients will subsequently die from disease progression.

MATERIALS AND METHODS

We examined the efficacy and toxicity of thalidomide, an anti-angiogenic agent, in combination with carboplatin and etoposide and as maintenance therapy in patients with untreated SCLC. Twenty-five chemotherapy-naive patients with extensive disease (ED) or limited disease (LD) SCLC were enrolled in a single-arm phase II study. Carboplatin and etoposide were given every 3 weeks for 6 cycles with concurrent thalidomide 100mg orally daily. The treatment with thalidomide was continued as maintenance for up to 2 years.

RESULTS

Median progression free and overall survival were 8.3 months and 10.1 months, respectively. One-year survival was 40% and the 1-year progression-free survival was 36%. The overall response rate was 68% (95% CI 46-85%) with four complete remissions (20%) and 13 partial remissions (48%). We observed no increase in chemotherapy related toxicity. Thalidomide was well-tolerated and median time on thalidomide treatment was 7.6 months.

CONCLUSION

Concurrent thalidomide with chemotherapy followed by maintenance thalidomide appears to be well tolerated. The results on tumour response rate and survival led us to initiate a randomised phase III trial in the United Kingdom.

Early experience with novel immunomodulators for cancer treatment

Immunotherapy involves the treatment of cancer by modification of the host-tumour relationship. It is now known that this relationship is quite complex and only some of the interactions have been elucidated. Early attempts at immunotherapy, such as Coley's toxins, were undertaken without an understanding of the processes mediating the effects. With a better understanding of the immunology of this anticancer response, recent trials have focussed on certain aspects of the process to stimulate an antitumour response. In this review, the authors discuss a number of novel biological response modifiers that work as general stimulants of the immune system, through varied mechanisms including induction of stimulatory cytokines (such as IFN-alpha, TNF-alpha and IL-12) and activation of T cells and the antigen-presenting dendritic cells. These compounds include Toll-like receptor agonists, several of which are in clinical trials at present. In addition to immunomodulatory activity, some compounds such as 5,6-dimethylxanthenone-4-acetic acid (DMXAA) and thalidomide and its analogues also target existing or developing tumour vasculature. Some of these compounds have single-agent activity in clinical trials, while others such as DMXAA have shown promise in combination with chemotherapy without increasing toxicity. Lactoferrin is another compound that has shown clinical activity with low toxicity. At present, accepted indications for immunotherapy are limited to a few cancers such as renal cell carcinoma and melanoma. This paper looks at some of the reasons for the limited impact of immunotherapy so far and suggest possible avenues for further research with a greater likelihood of success.

A phase II trial of thalidomide and cyclophosphamide in patients with recurrent or refractory pediatric malignancies

BACKGROUND

Previous clinical and pre-clinical research has demonstrated synergy between anti-angiogenic agents and cytotoxic chemotherapy. This trial was undertaken to investigate whether the combination of cyclophosphamide and thalidomide would be active against pediatric tumors.

PROCEDURE

Patients with pediatric malignancies who had no remaining conventional therapeutic options were recruited from January 1999 to May 2001. They received thalidomide (6-12 mg/kg po every day; maximum daily dose 800 mg) and cyclophosphamide (1,200 mg/m2 IV every 28 days).

RESULTS

Twenty-seven patients were enrolled on the study. Seventeen were male and 10 were female. Median age at the time of registration was 15 years (range 1-54 years). The median number of prior treatment regimens was four. Twenty-one patients were evaluable for response; 1 had a partial response (Hodgkin disease), 1 demonstrated stable disease (neuroendocrine tumor), and 19 had progressive disease. The most common toxicities were hematological (leukocytopenia and neutropenia) and gastrointestinal. One patient experienced a grade 3 rash. Fatigue and daytime somnolence were variable. No peripheral neuropathy was observed.

CONCLUSION

The combination of thalidomide and cyclophosphamide as described herein has a modest and tolerable toxicity profile but little evidence of efficacy.

Targeted therapy and blood-brain barrier

Due to defined molecular lesions and signaling pathway disruptions, brain tumors represent good candidates for targeted therapy. However, in brain tumors the blood-brain barrier may prevent the transfer of progress in the molecular neurosciences to the development of effective therapeutic strategies. In this article, the most advanced forms of targeted therapy for the treatment of brain tumors and their clinical results are presented.

Phase II trial of bevacizumab and irinotecan in recurrent malignant glioma

PURPOSE

Recurrent grade III-IV gliomas have a dismal prognosis with minimal improvements in survival seen following currently available salvage therapy. This study was conducted to determine if the combination of a novel antiangiogenic therapy, bevacizumab, and a cytotoxic agent, irinotecan, is safe and effective for patients with recurrent grade III-IV glioma.

EXPERIMENTAL DESIGN

We conducted a phase II trial of bevacizumab and irinotecan in adults with recurrent grade III-IV glioma. Patients with evidence of intracranial hemorrhage on initial brain magnetic resonance imaging were excluded. Patients were scheduled to receive bevacizumab and irinotecan i.v. every 2 weeks of a 6-week cycle. Bevacizumab was administered at 10 mg/kg. The dose of irinotecan was determined based on antiepileptic use: patients taking enzyme-inducing antiepileptic drugs received 340 mg/m(2), whereas patients not taking enzyme-inducing antiepileptic drugs received 125 mg/m(2). Toxicity and response were assessed.

RESULTS

Thirty-two patients were assessed (23 with grade IV glioma and 9 with grade III glioma). Radiographic responses were noted in 63% (20 of 32) of patients (14 of 23 grade IV patients and 6 of 9 grade III patients). The median progression-free survival was 23 weeks for all patients (95% confidence interval, 15-30 weeks; 20 weeks for grade IV patients and 30 weeks for grade III patients). The 6-month progression-free survival probability was 38% and the 6-month overall survival probability was 72%. No central nervous system hemorrhages occurred, but three patients developed deep venous thromboses or pulmonary emboli, and one patient had an arterial ischemic stroke.

CONCLUSIONS

The combination of bevacizumab and irinotecan is an active regimen for recurrent grade III-IV glioma with acceptable toxicity.

New chemotherapy options for the treatment of malignant gliomas

This review focuses on the recent advances in chemotherapy of malignant gliomas, with special emphasis on the most common primary brain tumor in adults, glioblastoma. The demonstration of the superiority of concomitant and adjuvant temozolomide with standard radiotherapy over radiotherapy alone in patients with newly diagnosed glioblastomas by means of phase III international trial has been the major advance in the care of these patients so far. Moreover, patients whose tumors display the hypermethylation of the promoter of the gene for the repairing enzyme O-methylguanine-DMA methyltransferase are most likely to benefit from the combination regimen. The advantage of a postsurgical local administration of carmustine by slow-release polymers ('gliadel wafers') is more modest, and the efficacy and safety of a sequence of carmustine wafers followed by temozolomide combined with radiotherapy remain to be defined. Different DNA repair modulation strategies are being investigated to further improve the results: dose-dense regimens of temozolomide, combination of temozolomide with specific inhibitors of O-methylguanine-DMA methyltransferase and combination of temozolomide with specific inhibitors of base excision repair [poly(ADP-ribose) polymerase inhibitors]. Other developments include the combination of cytotoxic, cytostatic and targeted therapies. Multitargeted compounds that simultaneously affect multiple signaling pathways, such as those involving epidermal growth factor receptor, platelet-derived growth factor receptor and vascular endothelial growth factor receptor, are increasingly employed. In the future, innovative trial designs (factorial and adaptative designs), pretreatment molecular profiling of individual tumors and the adoption of biological end-points (changes in serum tumor markers, measures of target inhibition), in addition to the traditional clinical and radiographic end-points, will be needed to achieve further advances.

Phase II study of metronomic chemotherapy for recurrent malignant gliomas in adults

Preclinical evidence suggests that continuous low-dose daily (metronomic) chemotherapy may inhibit tumor endothelial cell proliferation (angiogenesis) and prevent tumor growth. This phase II study evaluated the feasibility of this antiangiogenic chemotherapy regimen in adults with recurrent malignant gliomas. The regimen consisted of low-dose etoposide (35 mg/m2 [maximum, 100 mg/day] daily for 21 days), alternating every 21 days with cyclophosphamide (2 mg/kg [maximum, 100 mg/day] daily for 21 days), in combination with daily thalidomide and celecoxib, in adult patients with recurrent malignant gliomas. Serum and urine samples were collected for measurement of angiogenic peptides. Forty-eight patients were enrolled (15 female, 33 male). Twenty-eight patients had glioblastoma multiforme (GBMs), and 20 had anaplastic gliomas (AGs). Median age was 53 years (range, 33-74 years), and median KPS was 70 (range, 60-100). Therapy was reasonably well tolerated in this heavily pretreated population. Two percent of patients had partial response, 9% had a minor response, 59% had stable disease, and 30% had progressive disease. For GBM patients, median progression-free survival (PFS) was 11 weeks, six-month PFS (6M-PFS) was 9%, and median overall survival (OS) was 21 weeks. For AG patients, median PFS was 14 weeks, 6M-PFS was 26%, and median OS was 41.5 weeks. In a limited subset of patients, serum and urine angiogenic peptides did not correlate with response or survival (p > 0.05). Although there were some responders, this four-drug, oral metronomic regimen did not significantly improve OS in this heavily pretreated group of patients who were generally not eligible for conventional protocols. While metronomic chemotherapy may not be useful in patients with advanced disease, further studies using metronomic chemotherapy combined with more potent antiangiogenic agents in patients with less advanced disease may be warranted.

Oral thalidomide as palliative chemotherapy in women with advanced ovarian cancer

OBJECTIVE

We prospectively evaluated thalidomide, an oral agent with antiangiogenic and immunomodulatory properties, in patients with recurrent ovarian cancer, comparing the drug to standard intravenous chemotherapy and treatment holiday in terms of both progression-free interval and quality of life.

METHODS

Eligible patients had recurrent ovarian or primary peritoneal cancer and had received a minimum of two prior therapeutic regimens. Patients were offered one of three arms: (Arm A) any standard intravenous single-agent chemotherapy; (Arm B) oral thalidomide 200 mg daily; (Arm C) treatment holiday. Computed tomography (CT) scans were performed every two cycles until disease progression by Response Evaluation Criteria in Solid Tumors (RECIST) criteria. CA-125 was measured monthly as was quality of life using the Functional Assessment of Cancer Therapy (FACT-O) questionnaire.

RESULTS

Forty patients participated: 18 on Arm A; 18 on Arm B; and 4 on Arm C. The groups were comparable in terms of number of prior regimens and cycles of chemotherapy. The progression- free intervals were similar in Arm A and Arm B (3.7 versus 3.8 months). The PR/SD rate was 6.7%/60% for Arm A, and 7.7%/53.8% in Arm B. Of those treated with thalidomide, 53% had a drop in CA-125 greater than 50%, compared to 13% receiving intravenous chemotherapy. FACT-O scores at baseline and throughout treatment were equivalent.

CONCLUSION

The oral chemotherapeutic agent thalidomide appears to be comparable in response and quality of life, compared to single agent intravenous chemotherapy, in our population of heavily pretreated patients with ovarian cancer.

Venous thromboembolism and survival in patients with high-grade glioma

Patients with malignancy, particularly patients with high-grade glioma (HGG; WHO grade III/IV), have an increased risk of venous thromboembolism (VTE). It has been suggested that VTE predicts survival in cancer patients. The aim of our study was to investigate the occurrence of symptomatic VTE and its impact on survival in patients with HGG. Consecutive patients (n = 63; 36 female, 27 male; median age, 58 years) who had neurosurgical intervention between October 2003 and December 2004 were followed after surgery until October 2005. Objectively confirmed VTE was recorded as an event. All patients had received thrombosis prophylaxis with low-molecular-weight heparin (LMWH) during the immediate postoperative period. Subsequently, 56 patients received radiochemotherapy, 6 radiotherapy, and 1 chemotherapy only. Patients were followed over a median time period of 348 days. Fifteen patients (24%) developed VTE. Pulmonary embolism was diagnosed in nine patients (60%) and was fatal twice. The cumulative probability of VTE was 21% after three months and 26% after 12 months. The highest frequency of VTE was observed in patients with biopsy and subtotal tumor resection (n = 37; multivariate hazard ratio, 3.58; 95% CI = 0.98-13.13; P = 0.054) compared with patients with total resection. Survival did not significantly differ among patients with and without VTE and was 53% after 12 months in both groups. Patients with HGG, particularly those with biopsy and subtotal resection, are at high risk to develop VTE postoperatively. Thrombosis was not associated with a significant reduction of survival.

Different ways to antiangiogenesis by angiostatin and suramin, and quantitation of angiostatin-induced antiangiogenesis

Angiogenesis, i.e. sprouting of new vessels, their remodelling and regression, is a prerequisite for growth and differentiation of organs and tissues. It is involved in many pathological processes, particularly growth and metastasis of tumours. Angiostatic therapy is a promising new strategy in the treatment of cancer. Angiogenesis inhibitors could intervene in the different phases of the angiogenic cascade, i.e. migration, proliferation, differentiation and three-dimensional organisation of endothelial cells, to inhibit the generation of tumour vessels. The aim of this study was to explore whether in a previously validated in vitro model for quantitation of angiogenesis the effects of the angiostatic factors angiostatin and suramin can be investigated and quantified. Examination of angiostatin and suramin showed that angiostatin-induced antiangiogenesis resulted in inverse angiogenesis. The addition of suramin initially resulted in increased angiogenesis. However, long-term incubation ultimately led to disintegration of endothelial structures, thus establishing the angiostatic effects of suramin. Antiangiogenesis was not only quantified using the previously validated method. It also lent itself to assessment of the extent of antiangiogenesis within the various phases of the angiogenic cascade. This method may therefore be employed in trial studies of potential angiostatic substances and related cellular mechanisms.

Inhibition of 13-cis retinoic acid-induced gene expression of homeobox B7 by thalidomide

Thalidomide and 13-cis retinoic acid (RA) show anticancer effects as sole agents or in combination with other drugs. However, induction of homeobox (HOX) gene expression by 13-cis RA may contribute to tumor progression thereby potentially limiting its efficacy. The purpose was to test if thalidomide can inhibit 13-cis RA-induced HOXB7 expression and whether thalidomide may enhance the antiproliferative effect of 13-cis RA in U343MG glioblastoma cells. Quantitative real-time PCR showed significant inhibition of 13-cis RA-induced HOXB7 expression by thalidomide with IC(50) approximately 0.1-0.2 microg/ml when given simultaneously with 13-cis RA but not when administered 18 h later (p < 0.0001). 13-cis RA alone inhibited proliferation and colony formation in a concentration-dependent manner whereas growth inhibition by thalidomide alone at 5-100 microg/ml was constant at 80-90% of controls. At 10% serum concentration, growth inhibition by a combination of the 2 drugs was additive but at 1% serum, growth inhibition was synergistic. It is concluded that thalidomide inhibits the RA-induced HOXB7 expression in glioblastoma cells and that 13-cis RA/thalidomide combinations can in principle enhance cytotoxicity. The improved cell kill induced by thalidomide is attributed to downregulation of growth stimulatory factors induced by 13-cis RA. Implications for the modus operandi of thalidomide in embryogenesis are noted.

Phase II study of temozolomide and thalidomide in patients with metastatic melanoma in the brain: high rate of thromboembolic events (CALGB 500102)

BACKGROUND

Preliminary studies suggesting that extended-dose temozolomide with thalidomide is safe and active in patients with metastatic melanoma have led to frequent use of this oral regimen. To confirm these observations the combination was tested in a multicenter Phase II trial in patients with melanoma brain metastases.

METHODS

Eligible patients had melanoma brain metastases, with or without systemic metastases. The primary endpoint was response rate in brain metastases. Patients received temozolomide at a dose of 75 mg/m2/day for 6 weeks with a 2-week rest between cycles, and thalidomide (escalated to 400 mg/day for patients age < 70 years or to 200 mg/day for patients age > or = 70 years). A 2-stage design required > or = 3 responses in the first 21 patients before enrolling 29 additional patients in the second stage.

RESULTS

Sixteen eligible patients were enrolled. No objective responses were observed. The median survival was 23.9 weeks. Seven patients withdrew because of tumor progression; 7 were removed during Cycle 1 because of adverse events, including allergic reaction (1 patient), severe fatigue (1 patient), sudden death (1 patient), and thromboembolic events (pulmonary embolism in 3 patients and deep vein thrombosis in 1 patient); 2 patients withdrew when the study was suspended and subsequently closed. No associations could be established between baseline characteristics and toxicity.

CONCLUSIONS

The proportion of patients with lethal or potentially life-threatening adverse events was high (0.31, 95% confidence interval, 0.11-0.59), and the absence of objective responses made it unlikely that further accrual would demonstrate the efficacy of the regimen. These observations provide little support for the use of this combination for melanoma brain metastases unless safe and effective methods to prevent thrombosis are developed.

New approaches to primary brain tumor treatment

Primary brain tumors represent over 100 different tumor types with widely divergent biologies and clinical outcomes, but these neoplasms frequently pose similar challenges to neuro-oncologists. Malignant gliomas are the most common type of primary intrinsic brain tumor in adults and remain extremely lethal. Current standard-of-care therapies for these cancers include surgery, radiation and palliative cytotoxics, which have significant side-effects and limited efficacy. Advances in our understanding of the molecular underpinnings of cancer have led to targeted molecular therapies that may permit improvement in therapeutic efficacy and reduced toxicity; these therapies, however, still face many challenges. Signal transduction pathways that are inappropriately regulated in brain cancers include growth factors and their receptors (e.g. epidermal growth factor receptor, vascular endothelial growth factor receptor and platelet-derived growth factor receptor), which regulate cellular interactions with the microenvironment and intracellular oncogenic pathways. Low-molecular-weight inhibitors have been developed to target many kinases and may have advantages in terms of delivery. Monoclonal antibodies may have greater specificity, but face delivery restrictions. Preferential tumor delivery of chemotherapies, conjugated toxins and radioisotopes has been achieved through convection-enhanced delivery, intratumoral implants and intra-arterial infusion. Despite these advances, few molecularly targeted therapies have demonstrated significant antineoplastic activity for a broad range of patients, possibly due to tumor and patient heterogeneity. Improved functional neuropathology and imaging may permit identification of patient subgroups for which clinical responses may be enriched. It is probable, however, that targeted therapies will be most effective in combination either with one another or with cytotoxic therapies. In this study, we review the current state of new therapies for malignant gliomas.

Therapeutic options for recurrent high-grade glioma in adult patients: Recent advances

Despite of postoperative radiotherapy plus temozolomide for newly diagnosed glioblastoma multiforme (GBM) and improvements in the molecular characterization of high-grade glioma, these tumors continue to relapse. We reviewed all clinical studies of re-treatment published between May 2000 and September 2005. In groups of highly selected patients with re-treatment for GBM, median survival reaches 26-27 months. Re-treatment was stereotactic radiotherapy (mostly with additional chemotherapy) or re-resection plus either photodynamic treatment, radioimmunotherapy and temozolomide, or systemic and local chemotherapy. Thus, intense local treatment was always a component of more successful strategies. Additional data suggest that chemotherapy is more efficacious when minimal residual disease is present, although the recent trials have not uncovered a clear regimen of choice. Early trials of immunotherapy and toxin-delivery demonstrate the feasibility of these approaches and encouraging median survival times. Response to erlotinib was more common if tumors had epidermal growth factor receptor gene amplification, protein overexpression and low levels of phosphorylated PKB/Akt. Individual tailoring of such strategies based on molecular profiling is hoped to improve the outcome.

Anti-angiogenic therapy: Prospects for treatment of ocular tumors

The growth of new blood vessels (angiogenesis) within tumors is essential for tumor growth, maintenance, and metastasis. Angiogenesis research has identified a host of pro- and anti-angiogenic factors that regulate an "angiogenic switch," which when turned on, allows tumors to assume a more aggressive form. Angiogensis inhibitors that target this switch are in clinical trials for a wide array of tumor types. Although angiogenesis inhibitors are already widely used to treat ocular disease, only limited case reports are currently available for the use of angiogenesis inhibitors to treat ocular tumors. Evidence for angiogenesis in the growth and spread of uveal melanoma, retinoblastoma, and von Hippel Lindau (VHL) disease exists. The very limited trials of angiogenesis inhibitors in the treatment of uveal melanoma and VHL are promising, although more extensive controlled trials will be needed to confirm their efficacy.

Therapeutic advances in the treatment of glioblastoma: rationale and potential role of targeted agents

Despite advances in standard therapy, including surgical resection followed by radiation and chemotherapy, the prognosis for patients with glioblastoma multiforme (GBM) remains poor. Unfortunately, most patients die within 2 years of diagnosis of their disease. Molecular abnormalities vary among individual patients and also within each tumor. Indeed, one of the distinguishing features of GBM is its marked genetic heterogeneity. Nonetheless, recent developments in the field of tumor biology have elucidated signaling pathways and genes involved in the development of GBM, and several novel agents that target these signaling pathways are being developed. As new details on the genetic characteristics of this disease become available, innovative treatment regimens, including a variety of traditional treatment modalities such as surgery, radiation, and cytotoxic chemotherapy, will be combined with newer targeted therapies. This review introduces these new targeted therapies in the context of current treatment options for patients with GBM. It is hoped that this combined approach will overcome the current limitations in the treatment of patients with GBM and result in a better prognosis for these patients.

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

A phase II study was conducted to assess the efficacy of administering daily thalidomide concomitantly with radiation and continuing for up to 1 year following radiation in children with brain stem gliomas (BSG) or glioblastoma multiforme (GBM). Secondary objectives were to obtain preliminary evidence of biologic activity of thalidomide and to evaluate toxicities from chronic administration of thalidomide in this population. Thirteen patients (2-14 years old) with newly diagnosed BSG (12 patients) or GBM (one patient) were enrolled between July 1999 and June 2000. All patients received focal radiotherapy to a total dose of 5,580 cGy. Thalidomide was administered once daily beginning on the first day of radiation and continued for 12 months or until the patient came off study. The starting dose was 12 mg/kg (rounded down to the nearest 50 mg) and was increased by 20% weekly, if tolerated, to 24 mg/kg or 1,000 mg (whichever was lower). Advanced imaging techniques and urine and serum analysis for anti-angiogenic markers were performed in some patients in an attempt to correlate changes with clinical effect of therapy. No patients completed the planned 12 months of thalidomide therapy and all have since died of disease progression. The median duration of therapy was 5 months (range 2-11 months). Nine patients came off study for progressive disease (PD), three patients due to toxicity and one patient withdrew consent. Several patients on this study required more extended courses of high dose steroids than would have been otherwise expected for this population due to significant peritumoral edema and necrosis. No consistent pattern emerged from the biologic correlative studies from 11 patients. However, advanced imaging with techniques such as MR spectroscopy, MR perfusion and 18-fluorodeoxyglucose positron emission tomography (FDG-PET) were helpful in distinguishing growing tumor from treatment effect and necrosis in some patients. The median time to progression (TTP) was 5 months (range 2-11 months) and the median time to death (TTD) was 9 months (range 5-17 months). In this small patient sample adding thalidomide to radiation did not improve TTP or TTD from historical controls, however, toxicity appeared to be increased.

A North American brain tumor consortium (NABTC 99-04) phase II trial of temozolomide plus thalidomide for recurrent glioblastoma multiforme

BACKGROUND

Laboratory and clinical data suggest that the anti-angiogenic agent, thalidomide, if combined with cytotoxic agents, may be effective against recurrent glioblastoma multiforme (GBM).

OBJECTIVES

To determine 6-month progression-free survival (6PFS) and toxicity of temozolomide plus thalidomide in adults with recurrent GBM.

PATIENTS AND METHODS

Eligible patients had recurrent GBM after surgery, radiotherapy, and/or adjuvant chemotherapy. Temozolomide was given at 150-200 mg/m(2)/day on days 1-5 of each 28-day cycle. Thalidomide was given orally at 400 mg at bedtime (days 1-28) and increased to 1,200 mg as tolerated. Patients were evaluated with magnetic resonance imaging scans every 56 days. The study was designed to detect an increase of the historical 6PFS for GBM from 10 to 30%.

RESULTS

Forty-four patients were enrolled, 43 were evaluable for efficacy and safety. The study population included 15 women, 29 men; median age was 53 years (range 32-84); median Karnofsky performance status was 80% (range 60-100%). Thirty-six (82%) patients were chemotherapy-naïve. There were 57 reports of toxicity of grade 3 or greater. Non-fatal grade 3-4 granulocytopenia occurred in 15 patients (34%). The objective response rate was 7%. The estimated probability of being progression-free at 6 months with this therapy is 24% [95% confidence interval (C.I.) 12-38%]. The median time to progression is 15 weeks (95% C.I. 10-20 weeks). There was no observed correlation between serum levels of vascular endothelial growth factor, basic fibroblast growth factor, and IL-8 and the 6PFS outcome.

CONCLUSION

This drug combination was reasonably safe, but with little indication of improvement compared to temozolomide alone.

Angiogenesis in malignant glioma--a target for antitumor therapy?

The prognosis of malignant gliomas is still dismal despite aggressive treatment attempts. Thus, alternative therapy strategies are needed. Malignant gliomas are upon the best vascularized tumors in humans and their proliferation is hallmarked by a distinct proliferative vascular component. Hence it seems to be a logical consequence to apply anti-angiogenic treatment strategies to malignant gliomas. These treatment strategies have shown promising effects in animal models and some experimental clinical studies. This review gives a short introduction into the molecules involved in angiogenesis of malignant gliomas, it provides an overview of the latest experimental developments of glioma angiogenesis inhibition and discusses the results of clinical anti-angiogenic trials in patients with high grade glioma. Additionally the problem of monitoring the treatment success of an anti-angiogenic therapy is addressed.

Chemotherapy in the treatment of malignant gliomas

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

Inhibitory effect of thalidomide on the growth, secretory function and angiogenesis of estrogen-induced prolactinoma in Fischer 344 rats

The process of angiogenesis has been found to be essential for the development of estrogen-induced pituitary prolactinoma in Fischer 344 rats. Thalidomide [(alpha-(N-phthalimido)-glutarimide] is known to be a potent immunomodulatory drug with antiangiogenic properties, but its effect on lactotroph cell secretory function and pituitary prolactinoma formation has not been described yet. The purpose of this study was to examine the effects of thalidomide on secretion of prolactin (PRL) and vascular endothelial growth factor (VEGF), cell proliferation, apoptosis and angiogenesis within the anterior pituitary gland in long-term diethylstilboestrol (DES)-treated male F344 rats in vivo and in vitro. It was found that DES sharply increased serum PRL and VEGF levels. On the other hand, simultaneous treatment of F344 rats with thalidomide for the last 15 days of the experiment attenuated the stimulatory effect of DES on PRL and VEGF secretion. It also diminished prolactin cell proliferation evaluated as the number of proliferating cell nuclear antigen (PCNA)-positive stained cell nuclei and increased the number of apoptotic bodies determined by the terminal deoxynucleotidyl-mediated dUTP nick-end labeling (TUNEL) method in sections of the DES-induced pituitary prolactinoma. The density of pituitary microvessels evaluated by microscopic counting of CD-31-positive blood vessels was also diminished by the tested drug. In addition, thalidomide (10(-4) to 10(-6) M) inhibited cell proliferation, prolactin and VEGF secretion from rat pituitary prolactinoma cells cultured in vitro. In conclusion, our results provide strong evidence for the antiprolactin and antitumor activity of thalidomide in experimentally DES-induced pituitary adenoma.

Local delivery of a synthetic endostatin fragment for the treatment of experimental gliomas

OBJECTIVE

Endostatin is an anti-angiogenic agent that blocks matrix-metalloproteinase-2 and inhibits endothelial cell proliferation. Currently, endostatin is available through recombinant technology, which limits its broader use. In this study, a synthetic endostatin fragment (EF) was analyzed to determine its anti-angiogenic properties when locally delivered by controlled-release polymers and to establish its effect as a treatment for experimental gliomas.

METHODS

Cytotoxicity of EF against 9L gliosarcoma and F98 glioma was determined in vitro. EF was loaded into polyanhydride-poly-(bis-[carboxyphenoxy-propane]-sebacic-acid) (pCPP:SA) polymers at increasing concentrations. Pharmacokinetics of the EF/polymer formulations were defined in vitro. Anti-angiogenic properties of the EF/polymer formulations were evaluated in the rat-cornea micropocket assay. Toxicity and efficacy of locally delivered EF polymers either alone or combined with systemic bischloroethylnitrosourea (carmustine) were determined in rats intracranially challenged with 9L gliosarcoma.

RESULTS

EF showed scarce cytotoxicity against 9L and F98 in vitro. EF/pCPP:SA formulations showed sustained release by day 19. Mean corneal angiogenesis index 20 days after tumor implantation was 4.5 +/- 0.7 for corneas implanted with 40% EF/pCPP:SA compared with controls (8.5 +/- 1.3, P = 0.02). Intracranial efficacy studies showed that EF polymers alone did not prolong animal survival. Combination of 40% EF/pCPP:SA polymers with systemic bischloroethylnitrosourea (carmustine) prolonged survival (median survival of 44 d, P = 0.001) and generated 33% long-term survivors.

CONCLUSION

Controlled-release polymers can effectively deliver a biologically active EF in a sustained fashion. EF inhibits angiogenesis in vitro and in vivo, and even though EF does not prolong survival as a single agent, it exhibits a synergistic effect when combined with systemic bischloroethylnitrosourea (carmustine) in the intracranial 9L gliosarcoma model.

Cystemustine in recurrent high grade glioma

In this study, we have assessed the efficacy of a nitrosourea, cystemustine, in treating patients with recurrent high grade glioma with overall survival analysis as primary end-point. Forty-eight patients with recurrent high grade glioma (24 glioblastomas, 17 astrocytomas and 5 oligodendrogliomas) were treated every 2 weeks with 60 mg/m2 cystemustine by a 15 min-infusion. The median number of treatment cycles was 4 (range 1-17). The median overall survival was 8.3 months (range 1-97) and the 6- and 12-month overall survival rates were 55.3% (95% CI, 41.3-68.6%) and 29.8% (95% CI, 18.6-44.0%), respectively. The objective response rate was 18.8% (95% CI, 7.7-29.9%), and 54.2% of patients had stable disease (95% CI, 40.1-68.3%). Multivariate analysis showed that WHO performance status, histology and response to cystemustine were significant prognostic factors for survival of patients with recurrent glioma. In conclusion, cystemustine has encouraging activity for patients with recurrent high grade glioma.

Recent developments in the use of chemotherapy in brain tumours

Several recent studies have further clarified the role of chemotherapy in newly diagnosed anaplastic glioma. For newly diagnosed glioblastoma, combined daily radiotherapy with daily temozolomide followed by six cycles of adjuvant temozolomide improves overall survival. This benefit is especially observed in patients with a methylated promotor of the MGMT gene which encodes an alkyltransferase; this observation however, needs confirmation. Although oligodendroglial tumours are sensitive to chemotherapy, classical adjuvant nitrosourea-based chemotherapy does not improve overall survival in newly diagnosed anaplastic oligodendroglioma, even in the subset of 1p/19q loss tumours. It may increase progression-free survival however, and further studies must show if combined modality treatment with daily chemotherapy during radiotherapy increases survival. Trials exploring the role of chemotherapy in low-grade glioma are ongoing. No standard chemotherapy is currently available for highly anaplastic glioma failing first-line temozolomide-based therapy.

Angiogenic inhibitors: a new therapeutic strategy in oncology

Angiogenesis is a multistep, complex and tightly regulated process that is necessary for tumor growth and metastasis. Based on data of preclinical models, several antiangiogenic compounds has been shown to modify activated tumor endothelium, which suggests that these compounds can improve cytotoxic drug delivery. Such agents have entered clinical trials as single agents or in combination with cytotoxic drugs, and have shown promising antitumor activity. The pharmacodynamic and pharmacokinetic characteristics of antiangiogenic drugs are reviewed here. Most of the early clinical testing of these agents was conducted in patients with advanced disease resistant to standard therapies. Phase III trials compared the efficacy of standard chemotherapy alone with standard chemotherapy in combination with an experimental angiogenesis inhibitor. Although some of these studies were negative or controversial, recent studies validated in large clinical trials with an anti-vascular endothelial growth factor antibody demonstrated significant clinical benefit and renewed enthusiasm for this therapeutic strategy. This review describes the clinical studies of antiangiogenic agents and highlights the challenges related to choosing appropriate strategies for the selection of patients, study design and choice of appropriate endpoints for the studies' development.

Therapy for recurrent malignant glioma in adults

Malignant gliomas are the most common form of primary brain tumors in adults. Although the prognosis remains poor, there has been recent progress in the treatment of these tumors. Standard therapy for patients with this disease will be reviewed, together with more novel approaches such as targeted molecular therapies, angiogenesis inhibitors, immunotherapies, gene therapies and intratumoral therapies.

Phase I trial of thalidomide and Interleukin-2 in patients with metastatic renal cell carcinoma

BACKGROUND

The treatment of advanced renal cell cancer remains unsatisfactory, therefore new combination regimens such as thalidomide and IL-2 are of interest. A phase I trial of SC IL-2 and oral thalidomide was performed to identify the toxicity, maximum tolerated dose (MTD) and preliminary clinical activity of this regimen.

METHODS

33 patients with advanced/metastatic RCC were enrolled. An established 8-week outpatient schedule of subcutaneously administered IL-2 in escalating doses, days 1-5, for 6 weeks with a 2 week rest was utilized with daily oral thalidomide. Cohorts of 4-6 patients were treated at 4 dose levels.

RESULTS

Toxicity was moderate to severe and related to dose level. All patients developed fever, chills and fatigue. 29/33 patients developed < or = Grade 2 desquamation of hands and feet and/or rash. Dose limiting toxicity (DLT) included Grade 3 neutropenia and pulmonary embolus. The maximum tolerated dose (MTD) of IL-2 and thalidomide was 9.0 MIU/m2 s.c. days 1-5, weeks 1 to 6 and 100 mg p.o. daily, respectively. A median of 2 cycles of therapy was administered (range 1-9). 2/33 patients responded (1 CR--prior IL-2 therapy, 1 PR--no prior therapy) with an overall response of 6% (95% CI, 1-20%). One minimal response was converted to a surgical CR (remains disease free at 24 + months).

CONCLUSION

Outpatient administration of IL-2 and thalidomide is possible with acceptable toxicity. Further evaluation of this regimen is underway.

Targeted molecular therapy of malignant gliomas

Malignant gliomas are the most common form of primary brain tumors in adults. Despite advances in diagnosis and standard therapies such as surgery, radiation, and chemotherapy, the prognosis remains poor. Recent scientific advances have enhanced our understanding of the biology of gliomas and the role of tyrosine kinase receptors and signal transduction pathways in tumor initiation and maintenance, such as the epidermal growth factor receptors, platelet-derived growth factor receptors, vascular endothelial growth factor receptors, and the Ras/Raf/mitogen-activated protein (MAP)-kinase and phosphatidylinositol-3 kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathways. Novel targeted drugs such as small molecular inhibitors of these receptors and signaling pathways are showing some activity in initial studies. As we learn more about these drugs and how to optimize their use as single agents and in combination with radiation, chemotherapy, and other targeted molecular agents, they will likely play an increasing role in the management of this devastating disease. This review summarizes the current results with targeted molecular agents in malignant gliomas and strategies under evaluation to increase their effectiveness.

Angiogenesis in gliomas: imaging and experimental therapeutics

Much of the interest in angiogenesis and hypoxia has led to investigating diagnostic imaging methodologies and developing efficacious agents against angiogenesis in gliomas. In many ways, because of the cytostatic effects of these agents on tumor growth and tumor-associated endothelial cells, the effects of therapy are not immediately evident. Hence finding clinically applicable imaging tools and pathologic surrogate markers is an important step in translating glioma biology to therapeutics. There are a variety of strategies in the approach to experimental therapeutics that target the hypoxia-inducible factor pathway, the endogenous antiangiogenic and proangiogenic factors and their receptors, adhesion molecules, matrix proteases and cytokines, and the existing vasculature. We discuss the rationale for antiangiogenesis as a treatment strategy, the preclinical and clinical assessment of antiangiogenic interventions and finally focus on the various treatment strategies, including combining antiangiogenic drugs with radiation and chemotherapy.

Recent clinical studies of the immunomodulatory drug (IMiD) lenalidomide

Thalidomide is effective in the treatment of multiple myeloma. The immunomodulatory drug and thalidomide analogue lenalidomide is currently in late stage clinical development for MDS and multiple myeloma. This minireview highlights the course of initial and ongoing lenalidomide clinical development in oncology with reference to earlier thalidomide studies.