epothilone-a and Glioma

Based on preclinical data indicating the radiosensitizing potential of epothilone B, the present study was designed to evaluate the toxicity and response rate of patupilone, an epothilone B, with concurrent radiotherapy (RT) for the treatment of central nervous system malignancies.. The present Phase I study evaluated the toxicities associated with patupilone combined with RT to establish the maximal tolerated dose. Eligible patients had recurrent gliomas (n = 10) primary (n = 5) or metastatic (n = 17) brain tumors. Dose escalation occurred if no dose-limiting toxicities, defined as any Grade 4-5 toxicity or Grade 3 toxicity requiring hospitalization, occurred during treatment.. Of 14 patients, 5 were treated with weekly patupilone at 1.5 mg/m(2), 4 at 2.0 mg/m(2), 4 at 2.5 mg/m(2), and 1 at 4 mg/m(2). Of 18 patients, 7 were treated in the 6-mg/m(2) group, 6 in the 8-mg/m(2) group, and 5 in the 10-mg/m(2) group. Primary central nervous system malignancies received RT to a median dose of 60 Gy. Central nervous system metastases received whole brain RT to a median dose of 37.4 Gy, and patients with recurrent gliomas underwent stereotactic RT to a median dose of 37.5 Gy. One dose-limiting toxicity (pneumonia) was observed in group receiving 8-mg/m(2) every 3 weeks. At the subsequent dose level (10 mg/m(2)), two Grade 4 dose-limiting toxicities occurred (renal failure and pulmonary hemorrhage); thus, 8 mg/m(2) every 3 weeks was the maximal tolerated dose and the recommended Phase II dose.. Combined with a variety of radiation doses and fractionation schedules, concurrent patupilone was well tolerated and safe, with a maximal tolerated dose of 8 mg/m(2) every 3 weeks.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Brain Neoplasms; Combined Modality Therapy; Drug Administration Schedule; Epothilones; Female; Glioma; Hemorrhage; Humans; Lung Diseases; Male; Maximum Tolerated Dose; Middle Aged; Pneumonia; Radiation-Sensitizing Agents; Radiotherapy Dosage; Tubulin Modulators; Young Adult

Ixabepilone is an epothilone, a novel class of non-taxane microtubule stabilizing agents. A phase I/II and pharmacokinetic trial of ixabepilone was conducted in patients with recurrent high-grade gliomas. Adult patients received ixabepilone as a 1-h infusion daily for 5 days every 3 weeks. A modified continual reassessment method was used to escalate doses, beginning at 5.0 mg/m(2), in patients stratified by use or non-use of enzyme inducing antiepileptic drugs (EIAED). In the phase I study, the maximum tolerated dose (MTD) and pharmacokinetics of ixabepilone were determined for each group. The phase II study used a two-stage design to evaluate response rate. Secondary endpoints were survival and 6-month progression free survival. In the phase I trial, 38 patients (median age 54 years) were enrolled. The MTD was 6.8 mg/m(2) for patients not taking EIAEDs and 9.6 mg/m(2) for those taking EIAEDs. The dose limiting toxicities in both groups were hematologic. Twenty-three patients (median age 54 years) were enrolled in the first stage of the phase II trial. No objective responses were observed. Median overall survival was 5.8 (95% CI, 5.0-8.6) months and 6-month PFS rate was 4% (95% CI, 0-22%). The overall mean total body clearance for ixabepilone was significantly higher (P = 0.003) in patients receiving EIAEDs (36 ± 11 l/h/m(2)) than those not (24 ± 9.2 l/h/m(2)). Patients on EIAEDs had a substantially higher MTD likely due to induction of cytochrome P450. Ixabepilone had no activity in patients with recurrent high-grade gliomas.

Topics: Adult; Aged; Anticonvulsants; Antineoplastic Agents; Brain Neoplasms; Disease-Free Survival; Epothilones; Female; Glioma; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasm Recurrence, Local; Young Adult

It has been demonstrated that sagopilone (ZK-EPO) has antitumor activity in human orthotopic glioma models in vitro and in vivo. The objective of this study was to evaluate the safety and efficacy of ZK-EPO in patients with pretreated, recurrent malignant gliomas. Fifteen patients with recurrent malignant gliomas who had received prior surgery, radiotherapy, and >or=2 lines of alkylating chemotherapy were recruited. ZK-EPO (16 mg/m(2)) was administered iv for 3 h every 21 days. The primary end point was six months progression-free survival (PFS-6); secondary end points were safety, toxicity, response rate, and median time to progression (TTP). Magnetic resonance imaging (MRI) evaluations were performed every two cycles and toxicity was evaluated at each cycle using common terminology criteria for adverse events (CTCAE 3.0). A median of four cycles was administered. The median TTP was 13 weeks. PFS-6 was achieved in five patients (33%), three with glioblastoma multiforme and two with anaplastic astrocytoma. The most common treatment-related adverse event was neuropathy, which occurred in 6/15 patients. ZK-EPO had an acceptable safety profile and clinically relevant activity in patients with pretreated, recurrent malignant gliomas.

Topics: Adolescent; Adult; Aged; Antineoplastic Agents; Benzothiazoles; Brain Neoplasms; Drug Administration Schedule; Epothilones; Female; Glioma; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Severity of Illness Index; Survival Analysis; Young Adult

Invasion of normal brain tissue by brain tumor cells is a major contributing factor to the recurrence and resistance of clinically diagnosed glioblastomas to therapy (surgery, chemotherapy, radiation). Here, we have assessed the efficacy of the microtubule inhibiting agent epothilone B on glioblastoma cell motility, a prerequisite cellular program of invasive glioblastomas. Using cell migration assays and immunofluorescence techniques we demonstrated that epothilone B abrogated glioblastoma cell motility as a consequence of α-actinin 4 redistristrubiton and the breakdown of cellular structures (leading edge, stress fibers) it is associated with during cell migration. Evaluation of the microtubule actin cross linking factor in glioblastoma cells also revealed epothilone B invoked changes in this cytoskeleton cross linking protein, resembling α-actinin 4 changes in response to epothilone B. We have demonstrated in this study that epothilone B antagonizes glioblastoma cell motility due to the disruption of cytoskeleton binding proteins that aide in preserving the structural organization of the cytoskeleton filamentous network. Furthermore, we provide preclincial evidence that epothilone B effects on glioblastomas are not limited to the impairment of dividing tumors cells but that it also targets migratory and invasive glioblastoma cells, suggesting that this agent has potential clinical benefit due to its ability to target divergent cellular programs in the glioblastoma tumor mass.

Topics: Actinin; Antineoplastic Agents; Brain Neoplasms; Cell Movement; Down-Regulation; Drug Evaluation, Preclinical; Epothilones; Glioma; Humans; Microfilament Proteins; Microtubules; Protein Multimerization; Protein Transport; Tubulin Modulators; Tumor Cells, Cultured

Patupilone is a microtubule stabilizer (MTS) currently in clinical development. Here, we evaluate the anti-cancer activity in vitro and in vivo in comparison to paclitaxel and describe the pharmacokinetics (PK) of patupilone in tumor-bearing nude mice and rats.. The potency in vitro of patupilone and two other MTS, paclitaxel and ixabepilone, was determined using human colon carcinoma cell lines with low (HCT-116, HT-29, RKO) and high (HCT-15) P-glycoprotein expression (P-gp), as well as two multi-drug resistance (MDR) model cell pairs, MCF7/ADR and KB-8511 cells and their respective drug-sensitive parental counterparts. The PK of patupilone was investigated in nude mice bearing HCT-15 or HT-29 xenografts and in rats bearing s.c. pancreatic CA20498 tumors or A15 glioma tumors. Anti-cancer activity in vivo was compared to that of paclitaxel using three different human tumor colon models. The retention and efficacy of patupilone was compared in small and large HT-29 xenografts whose vascularity was determined by non-invasive magnetic resonance imaging.. Patupilone was highly potent in vitro against four different colon carcinoma cell lines including those showing multi-drug-resistance. In contrast, paclitaxel and ixabepilone displayed significantly reduced activity with markedly increased resistance factors. In both rats and mice, a single i.v. bolus injection of patupilone (1.5-4 mg/kg) rapidly distributed from plasma to all tissues and was slowly eliminated from muscle, liver and small intestine, but showed longer retention in tumor and brain with no apparent elimination over 24 h. Patupilone showed significant activity against three human colon tumor models in vivo, unlike paclitaxel, which only had activity against low P-gp expressing tumors. In HT-29 tumors, patupilone activity and retention were independent of tumor size, blood volume and flow.. The high potency of patupilone, which is not affected by P-gp expression either in vitro or in vivo, and favorable PK, independent of tumor vascularity, suggest that it should show significant activity in colorectal cancer and in other indications where high P-gp expression may compromise taxane activity.

Topics: Animals; Antineoplastic Agents; ATP Binding Cassette Transporter, Subfamily B, Member 1; Breast Neoplasms; Carcinoma; Cell Line, Tumor; Colonic Neoplasms; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Epothilones; Female; Glioma; Magnetic Resonance Imaging; Mice; Mice, Nude; Microtubules; Neoplasm Proteins; Paclitaxel; Pancreatic Neoplasms; Rats; Rats, Inbred Lew; Tissue Distribution; Xenograft Model Antitumor Assays

The microtubule-stabilizing agent patupilone (epothilone B, EPO906) and the tyrosine kinase inhibitor imatinib (STI571, Glivec) which primarily inhibits Bcr-Abl, PDGF and c-Kit tyrosine kinase receptors, were combined in vivo to determine if any interaction would occur with respect to antitumour effect and tolerability using rat C6 glioma xenografted into nude mice.. Patupilone and imatinib were administered alone or in combination at suboptimal doses. Imatinib treatment (orally once daily) was initiated 4 days after s.c. injection of rat C6 glioma cells into athymic nude mice and patupilone administration (i.v. once per week) was started 3 or 4 days after imatinib treatment.. As a single agent, imatinib was inactive in the regimens selected (100 mg/kg: T/C 86% and 116%; 200 mg/kg: T/C 68% and 84%; two independent experiments), but well tolerated (gain in body weight and no mortalities). Patupilone weekly monotherapy demonstrated dose-dependent antitumour effects (1 mg/kg: T/C 67% and 70%; 2 mg/kg: T/C 32% and 63%; 4 mg/kg: T/C 3% and 46%). As expected, dose-dependent body weight losses occurred (final body weight changes at 1 mg/kg were -7% and -3%; at 2 mg/kg were -23% and -13%; and at 4 mg/kg were -33% and -15%). Combining 2 mg/kg patupilone and 200 mg/kg per day imatinib in one experiment produced a non-statistically significant trend for an improved antitumour effect over patupilone alone (combination, T/C 9%), while in the second experiment, enhancement was seen with the combination and reached statistical significance versus patupilone alone (combination, T/C 22%; P=0.008). Reduction of the imatinib dose to 100 mg/kg per day resulted in no enhancement of antitumour activity in combination with 2 mg/kg patupilone. Reduction of the patupilone dose to 1 mg/kg resulted in a reduced antitumour effect, and only a trend for synergy with either imatinib dose (combination, T/C 46% and 40%). Pooling the data from the two experiments confirmed a significant synergy for the combination of 2 mg/kg patupilone and 200 mg/kg per day imatinib (P=0.032), and a trend for synergy at the 1 mg/kg patupilone dose. Reduction in the imatinib dose to 100 mg/kg per day resulted only in additivity with either dose of patupilone. Body weight losses were dominated by the effect of patupilone, since no greater body weight loss was observed in the combination groups.. Combining patupilone with high-dose imatinib produced an increased antitumour effect without affecting the tolerability of treatment in a relatively chemoresistant rat C6 glioma model. Such results indicate that further evaluation is warranted, in particular to elucidate possible mechanisms of combined action.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Benzamides; Cell Line, Tumor; Dose-Response Relationship, Drug; Epothilones; Glioma; Imatinib Mesylate; Mice; Mice, Inbred BALB C; Mice, Nude; Neoplasm Transplantation; Piperazines; Pyrimidines; Rats

The purpose of this study was to investigate the potential effects of epothilones (EPOs), a new class of microtubule stabilizing cytotoxic drugs, on glioma cells in vitro. The effects of 1, 10 and 100 nM concentrations of EPO D in four malignant human glioma cell lines were measured using a microtiter-tetrazolium assay. Besides the cell lines U87MG, U138MG and LN405, one cell line was used, which had been derived from a recurrent and therapy-resistant glioblastoma in our laboratory. In addition, changes of the cell morphology were followed by light microscopy and changes in the microtubule and actin cytoskeleton were visualized by a confocal laser microscope. In all four human glioma cell lines, 10 and 100 nM concentrations of the drug, applied for 96 h, lead to a highly significant decrease in the viable cell number (p < 0.001). A mean reduction of the viable cell number between 30% and 40% (60% and 90%) was observed for a drug concentration of 10 nM (100 nM). A round cell morphology occured in most EPO treated cells and the organized network of microtubules was shrunk in these round cells. The tubulin immunostaining now appeared amorphous and was restricted to small perinuclear regions. Large actin filaments also disappeared, but actin staining was present in the whole cytosplasm. These results prove that EPOs have antiproliferative effects in glioma cells and affect their tubulin cytoskeleton, as it was previously observed in several types of carcinoma cells.

Topics: Actin Cytoskeleton; Actins; Antineoplastic Agents; Brain Neoplasms; Cell Division; Cell Survival; Cytoskeleton; Epothilones; Glioma; Humans; Microscopy, Confocal; Microtubules; Tubulin; Tumor Cells, Cultured

A new epothilone, 10,11-didehydroepothilone D (5), was isolated from a strain of the heterologous host Myxococcus xanthus genetically engineered to produce epothilone D (4). The structure of 5 was determined from NMR and MS data. The epothilone polyketide synthase was further modified in a recombinant M. xanthus strain to produce 5 as the major epothilone-related metabolite. The cytotoxicity of 5 against a panel of tumor cell lines, including several with multidrug resistance, and its effect on tubulin polymerization were comparable to epothilone D (4).

Topics: Antineoplastic Agents; Base Sequence; Binding Sites; Breast Neoplasms; Drug Screening Assays, Antitumor; Epothilones; Epoxy Compounds; Female; Genetic Engineering; Glioma; HL-60 Cells; Humans; Inhibitory Concentration 50; Leukemia, Promyelocytic, Acute; Leukemia, T-Cell; Lung Neoplasms; Mass Spectrometry; Molecular Sequence Data; Molecular Structure; Multienzyme Complexes; Myxococcus xanthus; Nuclear Magnetic Resonance, Biomolecular; Thiazoles; Tubulin; Tumor Cells, Cultured