abt-510 and Brain-Neoplasms

To determine the maximum tolerated dose of ABT-510, a thrombospondin-1 mimetic drug with antiangiogenic properties, when used concurrently with temozolomide and radiotherapy in patients with newly diagnosed glioblastoma.. Phase 1 dose-escalation clinical trial.. Comprehensive Cancer Center, University of Alabama at Birmingham. Patients A total of 23 patients with newly diagnosed, histologically verified glioblastoma enrolled between April 2005 and January 2007.. Four cohorts of 3 patients each received subcutaneous ABT-510 injection at doses of 20, 50, 100, or 200 mg/d. The maximum cohort was expanded to 14 patients to obtain additional safety and gene expression data. The treatment plan included 10 weeks of induction phase (temozolomide and radiotherapy with ABT-510 for 6 weeks plus ABT-510 monotherapy for 4 weeks) followed by a maintenance phase of ABT-510 and monthly temozolomide.. Patients were monitored with brain magnetic resonance imaging and laboratory testing for dose-limiting toxicities, defined as grades 3 or 4 nonhematological toxicities and grade 4 hematological toxicities. Therapy was discontinued if 14 maintenance cycles were completed, disease progression occurred, or if the patient requested withdrawal. Disease progression, survival statistics, and gene expression arrays were analyzed.. There were no grade 3 or 4 dose-limiting toxicity events that appeared related to ABT-510 for the dose range of 20 to 200 mg/d. A maximum tolerated dose was not defined. Most adverse events were mild, and injection-site reactions. The median time to tumor progression was 45.9 weeks, and the median overall survival time was 64.4 weeks. Gene expression analysis using TaqMan low-density arrays identified angiogenic genes that were differentially expressed in the brains of controls compared with patients with newly diagnosed glioblastoma, and identified FGF-1 and TIE-1 as being downregulated in patients who had better clinical outcomes.. ABT-510, at subcutaneous doses up to 200 mg/d, is tolerated well with concurrent temozolomide and radiotherapy in patients with newly diagnosed glioblastoma, and low-density arrays provide a useful method of exploring gene expression profiles.

Topics: Adult; Aged; Antineoplastic Agents, Alkylating; Antineoplastic Combined Chemotherapy Protocols; Brain Neoplasms; Combined Modality Therapy; Dacarbazine; Disease Progression; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Fibroblast Growth Factor 1; Gene Expression Regulation, Neoplastic; Glioblastoma; Humans; Kaplan-Meier Estimate; Magnetic Resonance Imaging; Male; Middle Aged; Oligopeptides; Receptor, TIE-1; Reverse Transcriptase Polymerase Chain Reaction; Temozolomide; Treatment Outcome

Anti-angiogenic therapies would be particularly beneficial in the treatment of malignant gliomas. Peptides derived from the second type 1 repeat (TSR) of thrombospondin-1 (TSP-1) have been shown to inhibit angiogenesis in non-glioma tumor models and a modified TSR peptide, ABT-510, has now entered into Phase II clinical trials of its efficacy in non-glioma tumors. As microvascular endothelial cells (MvEC) exhibit heterogeneity, we evaluated the ability of the modified TSR peptide (NAcSarGlyValDallolleThrNvalleArgProNHE, ABT-510) to inhibit malignant glioma growth in vivo and to induce apoptosis of brain microvessel endothelial cells (MvEC) propagated in vitro. We found that daily administration of ABT-510 until euthanasia (days 7 to 19), significantly inhibited the growth of human malignant astrocytoma tumors established in the brain of athymic nude mice. The microvessel density was significantly lower and the number of apoptotic MvEC was significantly higher (3-fold) in the tumors of the ABT-510-treated animals. Similar results were found using a model in which the established tumor is an intracerebral malignant glioma propagated in a syngeneic mouse model. ABT-510 treatment of primary human brain MvEC propagated as a monolayer resulted in induction of apoptosis in a dose- and time-dependent manner through a caspase-8-dependent mechanism. It also inhibited tubular morphogenesis of MvEC propagated in collagen gels in a dose- and caspase-8 dependent manner through a mechanism that requires the TSP-1 receptor (CD36) on the MvEC. These findings indicate that ABT-510 should be evaluated as a therapeutic option for patients with malignant glioma.

Topics: Angiogenesis Inhibitors; Animals; Apoptosis; Brain Neoplasms; Capillaries; Caspase 8; CD36 Antigens; Cell Proliferation; Disease Models, Animal; Glioma; Humans; Mice; Mice, Nude; Neovascularization, Pathologic; Oligopeptides; Repetitive Sequences, Amino Acid; Thrombospondins; Xenograft Model Antitumor Assays