Phase 2 trial of irinotecan and thalidomide in adults with recurrent anaplastic glioma

Potential Use of Thalidomide in Glioblastoma Treatment: An Updated Brief Overview

Glioblastoma is the most common malignant primary brain tumor in adults. Thalidomide is a vascular endothelial growth factor inhibitor that demonstrates antiangiogenic activity, and may provide additive or synergistic anti-tumor effects when co-administered with other antiangiogenic medications. This study is a comprehensive review that highlights the potential benefits of using thalidomide, in combination with other medications, to treat glioblastoma and its associated inflammatory conditions. Additionally, the review examines the mechanism of action of thalidomide in different types of tumors, which may be beneficial in treating glioblastoma. To our knowledge, a similar study has not been conducted. We found that thalidomide, when used in combination with other medications, has been shown to produce better outcomes in several conditions or symptoms, such as myelodysplastic syndromes, multiple myeloma, Crohn's disease, colorectal cancer, renal failure carcinoma, breast cancer, glioblastoma, and hepatocellular carcinoma. However, challenges may persist for newly diagnosed or previously treated patients, with moderate side effects being reported, particularly with the various mechanisms of action observed for thalidomide. Therefore, thalidomide, used alone, may not receive significant attention for use in treating glioblastoma in the future. Conducting further research by replicating current studies that show improved outcomes when thalidomide is combined with other medications, using larger sample sizes, different demographic groups and ethnicities, and implementing enhanced therapeutic protocol management, may benefit these patients. A meta-analysis of the combinations of thalidomide with other medications in treating glioblastoma is also needed to investigate its potential benefits further.

Antitumor effect of lenalidomide in malignant glioma cell lines

Glioblastoma is a malignant brain tumor exhibiting highly aggressive proliferation and invasion capacities. Despite treatment by aggressive surgical resection and adjuvant therapy including temozolomide and radiation therapy, patient prognosis remains poor. Lenalidomide, a derivative of thalidomide, is known to be an immunomodulatory agent that has been used to treat hematopoietic malignancies. There are numerous studies revealing an antitumor effect of lenalidomide in hematopoietic cells, but not in glioma cells. The present study aimed to demonstrate the antitumor effect of lenalidomide on malignant glioma cell lines. The growth inhibition of malignant glioma cells (A-172, AM-38, T98G, U-138MG, U-251MG, and YH-13) by lenalidomide was assessed using a Coulter counter. The mechanism of the antitumor effect of lenalidomide was examined employing a fluorescence-activated cell sorter, western blot analysis, and quantitative real-time reverse transcriptional polymerase chain reaction (RT-qPCR) in malignant glioma cell lines (A-172, AM-38). The results revealed that the number of malignant glioma cells was decreased in a concentration-dependent manner by lenalidomide. DNA flow cytometric analysis demonstrated an increase in the ratio of cells at the G₀/G₁ phase following lenalidomide treatment. Western blot analysis and RT-qPCR revealed that p53 activation and the expression of p21 were increased in glioma cells treated with lenalidomide. Western blot analysis revealed that cleavage of PARP did not occur; however, increased expression of Bax protein, cleavage of caspase-9 and cleavage of caspase-3 were confirmed. Analysis by FACS also supported the conclusion that little apoptosis induction occurred following lenalidomide treatment of malignant glioma cell lines. In conclusion, lenalidomide exerts an antitumor effect on glioma cells due to alterations in cell cycle distribution.

Adhesion molecules and the extracellular matrix as drug targets for glioma

The formation of tumor vasculature and cell invasion along white matter tracts have pivotal roles in the development and progression of glioma. A better understanding of the mechanisms of angiogenesis and invasion in glioma will aid the development of novel therapeutic strategies. The processes of angiogenesis and invasion cause the production of an array of adhesion molecules and extracellular matrix (ECM) components. This review focuses on the role of adhesion molecules and the ECM in malignant glioma. The results of clinical trials using drugs targeted against adhesion molecules and the ECM for glioma are also discussed.

Complications from pharmacotherapy

The pharmacotherapy management of cancers of the nervous system has significant overlap with systemic solid cancers that may utilize similar drugs or agents. There is however a unique aspect related to central nervous system (CNS) cancers where therapies directed against a malignant process may have enhanced toxicities or toxicities unique to the CNS. In addition, many agents used to treat CNS malignancies have unique CNS toxicities that may require a specific intervention. This chapter attempts to review conventional and biologic therapies utilized for CNS malignancies and characterize expected and, if known, unique toxicities.

The challenges and the promise of molecular targeted therapy in malignant gliomas

Malignant gliomas are the most common malignant primary brain tumors and one of the most challenging forms of cancers to treat. Despite advances in conventional treatment, the outcome for patients remains almost universally fatal. This poor prognosis is due to therapeutic resistance and tumor recurrence after surgical removal. However, over the past decade, molecular targeted therapy has held the promise of transforming the care of malignant glioma patients. Significant progress in understanding the molecular pathology of gliomagenesis and maintenance of the malignant phenotypes will open opportunities to rationally develop new molecular targeted therapy options. Recently, therapeutic strategies have focused on targeting pro-growth signaling mediated by receptor tyrosine kinase/RAS/phosphatidylinositol 3-kinase pathway, proangiogenic pathways, and several other vital intracellular signaling networks, such as proteasome and histone deacetylase. However, several factors such as cross-talk between the altered pathways, intratumoral molecular heterogeneity, and therapeutic resistance of glioma stem cells (GSCs) have limited the activity of single agents. Efforts are ongoing to study in depth the complex molecular biology of glioma, develop novel regimens targeting GSCs, and identify biomarkers to stratify patients with the individualized molecular targeted therapy. Here, we review the molecular alterations relevant to the pathology of malignant glioma, review current advances in clinical targeted trials, and discuss the challenges, controversies, and future directions of molecular targeted therapy.

A phase II trial of enzastaurin (LY317615) in combination with bevacizumab in adults with recurrent malignant gliomas

We evaluated the efficacy of combination enzastaurin (LY317615) and bevacizumab for recurrent malignant gliomas and explored serologic correlates. We enrolled 81 patients with glioblastomas (GBM, n = 40) and anaplastic gliomas (AG, n = 41). Patients received enzastaurin as a loading dose of 1125 mg, followed by 500 or 875 mg daily for patients on non-enzyme-inducing or enzyme-inducing antiepileptics, respectively. Patients received bevacizumab 10 mg/kg intravenously biweekly. Clinical evaluations were repeated every 4 weeks. Magnetic resonance imaging was obtained at baseline and every 8 weeks from treatment onset. Phosphorylated glycogen synthase kinase (GSK)-3 levels from peripheral blood mononuclear cells (PBMCs) were checked with each MRI. Median overall survival was 7.5 and 12.4 months for glioblastomas and anaplastic glioma cohorts, with median progression-free survivals of 2.0 and 4.4 months, respectively. Of GBM patients, 3/40 (7.5 %) were not evaluable, while 8/37 (22 %) had partial or complete response and 20/37 (54 %) had stable disease for 2+ months. Of the 39 evaluable AG patients, 18 (46 %) had an objective response, and 16 (41 %) had stable disease for 2+ months. The most common grade 3+ toxicities were lymphopenia (15 %), hypophosphatemia (8.8 %) and thrombotic events (7.5 %). Two (2.5 %) GBM patients died suddenly; another death (1.3 %) occurred from intractable seizures. Phosphorylated GSK-3 levels from PBMCs did not correlate with treatment response. A minimally important improvement in health-related quality of life was self-reported in 7-9/24 (29.2-37.5 %). Early response based on Levin criteria was significantly associated with significantly longer progression free survival for glioblastomas. Enzastaurin (LY317615) in combination with bevacizumab for recurrent malignant gliomas is well-tolerated, with response and progression-free survival similar to bevacizumab monotherapy.

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.

Targeted therapy in gliomas

The survival outcome of patients with malignant gliomas is still poor, despite advances in surgical techniques, radiation therapy and the development of novel chemotherapeutic agents. The heterogeneity of molecular alterations in signaling pathways involved in the pathogenesis of these tumors contributes significantly to their resistance to treatment. Several molecular targets for therapy have been discovered over the last several years. Therapeutic agents targeting these signaling pathways may provide more effective treatments and may improve survival. This review summarizes the important molecular therapeutic targets and the outcome of published clinical trials involving targeted therapeutic agents in glioma patients.

A conceptually new treatment approach for relapsed glioblastoma: coordinated undermining of survival paths with nine repurposed drugs (CUSP9) by the International Initiative for Accelerated Improvement of Glioblastoma Care

To improve prognosis in recurrent glioblastoma we developed a treatment protocol based on a combination of drugs not traditionally thought of as cytotoxic chemotherapy agents but that have a robust history of being well-tolerated and are already marketed and used for other non-cancer indications. Focus was on adding drugs which met these criteria: a) were pharmacologically well characterized, b) had low likelihood of adding to patient side effect burden, c) had evidence for interfering with a recognized, well-characterized growth promoting element of glioblastoma, and d) were coordinated, as an ensemble had reasonable likelihood of concerted activity against key biological features of glioblastoma growth. We found nine drugs meeting these criteria and propose adding them to continuous low dose temozolomide, a currently accepted treatment for relapsed glioblastoma, in patients with recurrent disease after primary treatment with the Stupp Protocol. The nine adjuvant drug regimen, Coordinated Undermining of Survival Paths, CUSP9, then are aprepitant, artesunate, auranofin, captopril, copper gluconate, disulfiram, ketoconazole, nelfinavir, sertraline, to be added to continuous low dose temozolomide. We discuss each drug in turn and the specific rationale for use- how each drug is expected to retard glioblastoma growth and undermine glioblastoma's compensatory mechanisms engaged during temozolomide treatment. The risks of pharmacological interactions and why we believe this drug mix will increase both quality of life and overall survival are reviewed.

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.

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.