Author
Erik C. Parker
Bio: Erik C. Parker is an academic researcher from New York University. The author has contributed to research in topics: Radiation therapy & Bevacizumab. The author has an hindex of 15, co-authored 27 publications receiving 1293 citations.
Topics: Radiation therapy, Bevacizumab, Radiosurgery, Melanoma, Glioma
Papers
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TL;DR: Antiangiogenic therapy using bevacizumab appears to improve survival in patients with recurrent high-grade glioma, and a possible change in the invasiveness of the tumor following therapy is worrisome and must be closely monitored.
Abstract: Object Antiangiogenic agents have recently shown impressive radiological responses in high-grade glioma. However, it is not clear if the responses are related to vascular changes or due to antitumoral effects. The authors report the mature results of a clinical study of bevacizumab-based treatment of recurrent high-grade gliomas. Methods Sixty-one patients with recurrent high-grade gliomas received treatment with bevacizumab at 10 mg/ kg every 2 weeks for 4 doses in an 8-week cycle along with either irinotecan or carboplatin. The choice of concomitant chemotherapeutic agent was based on the number of recurrences and prior chemotherapy. Results At a median follow-up of 7.5 months (range 1–19 months), 50 (82%) of 61 patients relapsed and 42 patients (70%) died of the disease. The median number of administered bevacizumab cycles was 2 (range 1–7 cycles). The median progression-free survival (PFS) and overall survival (OS) were 5 (95% confidence interval [CI] 2.3–7.7) and 9 (95% CI 7.6–10.4) months, respectiv...
247 citations
TL;DR: Administration of ipilimumab neither increased toxicity nor improved intracerebral disease control in patients with limited brain metastases who received SRS.
Abstract: The anti-cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) monoclonal antibody ipilimumab has been shown to improve survival in patients with metastatic non-CNS melanoma. The purpose of this study was to investigate the efficacy of CTLA-4 inhibitors in the treatment of metastatic melanoma with limited brain metastases treated with stereotactic radiosurgery (SRS). Between January 2008 and June 2011, 58 patients with limited brain metastases from melanoma were treated with SRS with a median dose of 20 Gy delivered to the 50% isodose line (range, 15-20 Gy). In 25 patients, ipilimumab was administered intravenously at a dose of 3 mg/kg over 90 min every 3 weeks for a median of four doses (range, 1-8). Local control (LC), freedom from new brain metastases, and overall survival (OS) were assessed from the date of the SRS procedure. The median LC, freedom from new brain metastases, and OS for the entire group were 8.7, 4.3, and 5.9 months, respectively. The cause of death was CNS progression in all but eight patients. Six-month LC, freedom from new brain metastases, and OS were 65, 35, and 56%, respectively, for those who received ipilimumab and 63, 47, and 46% for those who did not (P=NS). Intracranial hemorrhage was noted in seven patients who received ipilimumab compared with 10 patients who received SRS alone (P=NS). In this retrospective study, administration of ipilimumab neither increased toxicity nor improved intracerebral disease control in patients with limited brain metastases who received SRS.
164 citations
TL;DR: It was determined that intraoperative DEX infusion was effective for blunting the increases in SBP perioperatively and the use of DEX did not increase the incidence of hypotension or bradycardia, common side effects of the drug.
Abstract: BACKGROUND:The perioperative course of patients undergoing intracranial surgery is frequently complicated by hypertensive episodes. Dexmedetomidine (DEX), an α-2 adrenoreceptor agonist, is gaining popularity in neuroanesthesia, because its sympatholytic and antinociceptive properties may improve hem
124 citations
TL;DR: The addition of bevacizumab to conventional therapy in newly diagnosed glioblastoma appears to improve both PFS and OS in patients with newly diagnosed GBM, with acceptable morbidity.
Abstract: Object The presence of angiogenesis is a hallmark of glioblastoma (GBM). Vascular endothelial growth factor (VEGF), which drives angiogenesis, provides an additional target for conventional therapy. The authors conducted a prospective clinical trial to test the effectiveness of bevacizumab, an inhibitor of VEGF, in newly diagnosed GBM. Methods From 2006 through 2010, 51 eligible patients with newly diagnosed GBM were treated with involved-field radiation therapy and concomitant temozolomide (75 mg/m2 daily for 42 days) along with bevacizumab (10 mg/kg every 2 weeks), starting 29 days after surgery. This was followed by 6 cycles of adjuvant temozolomide therapy (150 mg/m2 on Days 1–7 of a 28-day cycle) with bevacizumab administered at 10 mg/kg on Days 8 and 22 of each 28-day cycle. Results The 6- and 12-month progression-free survival (PFS) rates were 85.1% and 51%, respectively. The 12- and 24-month overall survival (OS) rates were 85.1% and 42.5%, respectively. Grade III/IV toxicities were noted in 10 pa...
123 citations
TL;DR: This retrospective study suggests that melanoma patients with brain metastases harboring BRAF mutation appear to be a distinct sub-group with a favorable response to vemurafenib and radiation therapy and acceptable morbidity.
Abstract: Brain metastases in malignant melanoma carries a poor prognosis with minimal response to any therapy. The purpose of this pilot analysis was to find the effectiveness of vemurafenib, an oral BRAF inhibitor, and radiation therapy in V600 mutated melanoma with brain metastases. BRAF mutation status of the melanoma patients was determined by real-time PCR assay. Retrospective analysis was performed on twelve patients who had the mutation and were treated with either stereotactic radiosurgery or whole brain radiation therapy prior to or along with vemurafenib at a dose of 960 mg orally twice a day. Clinical and radiological responses, development of new brain metastases, overall survival and toxicity were assessed. Improvement in neurological symptoms was seen in 7/11 (64 %) following therapy. Radiographic responses were noted in 36/48 (75 %) of index lesions with 23 (48 %) complete responses and 13 (27 %) partial responses. Six month local control, freedom from new brain metastases and overall survival were 75, 57 and 92 %. Four patients had intra-tumoral bleed prior to therapy and two patients developed steroid dependence. One patient experienced radiation necrosis. This retrospective study suggests that melanoma patients with brain metastases harboring BRAF mutation appear to be a distinct sub-group with a favorable response to vemurafenib and radiation therapy and acceptable morbidity.
107 citations
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Journal Article•
2,777 citations
TL;DR: It is reported that angiogenesis inhibitors targeting the VEGF pathway demonstrate antitumor effects in mouse models of pancreatic neuroendocrine carcinoma and glioblastoma but concomitantly elicit tumor adaptation and progression to stages of greater malignancy, with heightened invasiveness and in some cases increased lymphatic and distant metastasis.
2,303 citations
TL;DR: The addition of bevacizumab to radiotherapy-temozolomide did not improve survival in patients with glioblastoma, and the glucocorticoid requirement was lower.
Abstract: Background Standard therapy for newly diagnosed glioblastoma is radiotherapy plus temozolomide. In this phase 3 study, we evaluated the effect of the addition of bevacizumab to radiotherapy–temozolomide for the treatment of newly diagnosed glioblastoma. Methods We randomly assigned patients with supratentorial glioblastoma to receive intravenous bevacizumab (10 mg per kilogram of body weight every 2 weeks) or placebo, plus radiotherapy (2 Gy 5 days a week; maximum, 60 Gy) and oral temozolomide (75 mg per square meter of body-surface area per day) for 6 weeks. After a 28-day treatment break, maintenance bevacizumab (10 mg per kilogram intravenously every 2 weeks) or placebo, plus temozolomide (150 to 200 mg per square meter per day for 5 days), was continued for six 4-week cycles, followed by bevacizumab monotherapy (15 mg per kilogram intravenously every 3 weeks) or placebo until the disease progressed or unacceptable toxic effects developed. The coprimary end points were investigator-assessed progression-free survival and overall survival. Results A total of 458 patients were assigned to the bevacizumab group, and 463 patients to the placebo group. The median progression-free survival was longer in the bevacizumab group than in the placebo group (10.6 months vs. 6.2 months; stratified hazard ratio for progression or death, 0.64; 95% confidence interval [CI], 0.55 to 0.74; P<0.001). The benefit with respect to progression-free survival was observed across subgroups. Overall survival did not differ significantly between groups (stratified hazard ratio for death, 0.88; 95% CI, 0.76 to 1.02; P = 0.10). The respective overall survival rates with bevacizumab and placebo were 72.4% and 66.3% at 1 year (P = 0.049) and 33.9% and 30.1% at 2 years (P = 0.24). Baseline health-related quality of life and performance status were maintained longer in the bevacizumab group, and the glucocorticoid requirement was lower. More patients in the bevacizumab group than in the placebo group had grade 3 or higher adverse events (66.8% vs. 51.3%) and grade 3 or higher adverse events often associated with bevacizumab (32.5% vs. 15.8%). Conclusions The addition of bevacizumab to radiotherapy–temozolomide did not improve survival in patients with glioblastoma. Improved progression-free survival and maintenance of baseline quality of life and performance status were observed with bevacizumab; however, the rate of adverse events was higher with bevacizumab than with placebo. (Funded by F. Hoffmann–La Roche; ClinicalTrials.gov number, NCT00943826.)
1,996 citations
TL;DR: The pathophysiology of tumor angiogenesis, the molecular underpinnings and functional consequences of vascular normalization, and the implications for treatment of cancer and nonmalignant diseases are reviewed.
Abstract: New vessel formation (angiogenesis) is an essential physiological process for embryologic development, normal growth, and tissue repair. Angiogenesis is tightly regulated at the molecular level. Dy...
1,296 citations
TL;DR: There is definite hope that by 2020, new cocktails of drugs will be available to target the key molecular pathways involved in gliomas and reduce their mortality and morbidity, a positive development for patients, their families, and medical professionals alike.
Abstract: Malignant gliomas are the most common and deadly brain tumors. Nevertheless, survival for patients with glioblastoma, the most aggressive glioma, although individually variable, has improved from an average of 10 months to 14 months after diagnosis in the last 5 years due to improvements in the standard of care. Radiotherapy has been of key importance to the treatment of these lesions for decades, and the ability to focus the beam and tailor it to the irregular contours of brain tumors and minimize the dose to nearby critical structures with intensitymodulated or image-guided techniques has improved greatly. Temozolomide, an alkylating agent with simple oral administration and a favorable toxicity profile, is used in conjunction with and after radiotherapy. Newer surgical techniques, such as fluorescence-guided resection and neuroendoscopic approaches, have become important in the management of malignant gliomas. Furthermore, new discoveries are being made in basic and translational research, which are likely to improve this situation further in the next 10 years. These include agents that block 1 or more of the disordered tumor proliferation signaling pathways, and that overcome resistance to already existing treatments. Targeted therapies such as antiangiogenic therapy with antivascular endothelial growth factor antibodies (bevacizumab) are finding their way into clinical practice. Large-scale research efforts are ongoing to provide a comprehensive understanding of all the genetic alterations and gene expression changes underlying glioma formation. These have already refined the classification of glioblastoma into 4 distinct molecular entities that may lead to different treatment regimens. The role of cancer stem-like cells is another area of active investigation. There is definite hope that by 2020, new cocktails of drugs will be available to target the key molecular pathways involved in gliomas and reduce their mortality and morbidity, a positive development for patients, their families, and medical professionals alike. CA Cancer J Clin 2010;60:166-193. © 2010 American Cancer Society, Inc.
1,261 citations