epothilone-a and Colonic-Neoplasms

Only a limited number of cytotoxic drugs have shown activity in metastatic colorectal carcinoma. Patupilone is a novel agent with promising activity in this common cancer. Diarrhea represents the dose-limiting toxicity of patupilone. Measurement of intestinal permeability is one of the potential methods of non-invasive laboratory assessment of gastrointestinal toxicity.. We have assessed intestinal permeability by measuring absorption of lactulose, mannitol and xylose in 27 previously treated patients with metastatic colorectal cancer enrolled in a phase I trial of patupilone.. Lactulose/mannitol and lactulose/xylose ratios increased after the treatment. Significantly higher lactulose/mannitol ratio was observed in patients who had severe diarrhea. Moreover, patients who subsequently had an adverse event of grade 3 or higher had significantly higher baseline lactulose/mannitol or lactulose/xylose ratios.. Measurement of intestinal permeability using the lactulose/mannitol test may represent a biomarker for the monitoring, or even prediction of toxicity of cytotoxic drugs, including patupilone.

Topics: Aged; Antineoplastic Agents; Colonic Neoplasms; Diarrhea; Epothilones; Female; Humans; Intestinal Mucosa; Intestines; Lactulose; Liver Neoplasms; Male; Mannitol; Middle Aged; Permeability; Xylose

New agents that are active in patients with metastatic colorectal cancer are needed. Patupilone (EPO906; epothilone B) is a novel microtubule-stabilising agent.. Patients with advanced colon cancer who progressed after prior treatment regimens received intravenous patupilone (6.5-10.0 mg m(-2)) once every 3 weeks by a 20-min infusion (20MI), 24-h continuous infusion (CI-1D) or 5-day intermittent 16-h infusion (16HI-5D). Adverse events (AEs), dose-limiting toxicities (DLTs), pharmacokinetics and anti-tumour activity were assessed.. Sixty patients were enrolled. The maximum tolerated dose (MTD) was not reached in the 20MI arm (n=31), as no DLTs were observed. Three patients in the CI-1D arm (n=26) experienced 1 DLT each at 7.5, 8.0 and 9.0 mg m(-2), but MTD was not reached. However, the prolonged 16HI-5D arm was terminated at 6.5 mg m(-2) after two of the three patients developed a DLT. Diarrhoea was the most common AE and DLT, with increased severity at the higher doses (9.0 and 10.0 mg m(-2)). Grade 3 or 4 diarrhoea was observed in 11 (35%) of the patients in the 20MI arm, 4 (15%) of the patients in the CI-1D arm and 2 (67%) of the patients in the 16HI-5D arm. Patupilone activity was observed in the 20MI arm with a disease control rate of 58%, including four confirmed partial responses. The disease control rate in CI-1D arm was 39%.. Patupilone given once every 3 weeks as a 20-min infusion had promising anti-tumour activity and manageable safety profile at doses that demonstrated therapeutic efficacy.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Colonic Neoplasms; Disease Progression; Dose-Response Relationship, Drug; Drug Administration Schedule; Epothilones; Female; Humans; Infusions, Intravenous; Male; Maximum Tolerated Dose; Middle Aged; Neoplasm Metastasis; Treatment Outcome

Ixabepilone (BMS-247550) is a semi-synthetic, microtubule stabilizing epothilone B analogue which is more potent than taxanes and has displayed activity in taxane-resistant patients. The human plasma pharmacokinetics of ixabepilone have been described. However, the excretory pathways and contribution of metabolism to ixabepilone elimination have not been determined. To investigate the elimination pathways of ixabepilone we initiated a mass balance study in cancer patients. Due to autoradiolysis, ixabepilone proved to be very unstable when labeled with conventional [14C]-levels (100 microCi in a typical human radio-tracer study). This necessitated the use of much lower levels of [14C]-labeling and an ultra-sensitive detection method, Accelerator Mass Spectrometry (AMS). Eight patients with advanced cancer (3 males, 5 females; median age 54.5 y; performance status 0-2) received an intravenous dose of 70 mg, 80 nCi of [14C]ixabepilone over 3 h. Plasma, urine and faeces were collected up to 7 days after administration and total radioactivity (TRA) was determined using AMS. Ixabepilone in plasma and urine was quantitated using a validated LC-MS/MS method. Mean recovery of ixabepilone-derived radioactivity was 77.3% of dose. Fecal excretion was 52.2% and urinary excretion was 25.1%. Only a minor part of TRA is accounted for by unchanged ixabepilone in both plasma and urine, which indicates that metabolism is a major elimination mechanism for this drug. Future studies should focus on structural elucidation of ixabepilone metabolites and characterization of their activities.

Topics: Adenocarcinoma; Antineoplastic Agents; Carcinoma, Non-Small-Cell Lung; Carcinoma, Squamous Cell; Chromatography, Liquid; Colonic Neoplasms; Epothilones; Feces; Female; Humans; Lung Neoplasms; Male; Middle Aged; Neoplasms; Ovarian Neoplasms; Pancreatic Neoplasms; Sigmoid Neoplasms; Tandem Mass Spectrometry

Resistance to microtubule-stabilizing agents is a major hurdle for successful cancer therapy. We investigated combined treatment of microtubule-stabilizing agents (MSAs) with inhibitors of angiogenesis to overcome MSA resistance.. Treatment regimens of clinically relevant MSAs (patupilone and paclitaxel) and antiangiogenic agents (everolimus and bevacizumab) were investigated in genetically defined MSA-resistant lung (A549EpoB40) and colon adenocarcinoma (SW480) tumor xenografts in nude mice (CD1-Foxn1, ICRnu; 5-14 per group). Tumor growth delays were calculated by Kaplan-Meier analysis with Holm-Sidak tests. All statistical tests were two-sided.. Inhibition of mTOR-kinase by everolimus only minimally reduced the proliferative activity of β tubulin-mutated lung adenocarcinoma cells alone and in combination with the MSA patupilone, but everolimus inhibited expression and secretion of vascular endothelial growth factor (VEGF) from these cells. mTOR-kinase inhibition strongly sensitized tumor xenografts derived from these otherwise MSA-resistant tumor cells to patupilone. Tumors treated with the combined modality of everolimus and patupilone had statistically significantly reduced tumor volume and stronger tumor growth delay (16.2 ± 1.01 days) than control- (7.7 ± 0.3 days, P = .004), patupilone- (10 ± 0.97 days, P = .009), and everolimus-treated (10.6 ± 1.4 days, P = .014) tumors. A combined treatment modality with bevacizumab also resensitized this MSA-refractory tumor model to patupilone. Treatment combination also strongly reduced microvessel density, corroborating the relevance of VEGF targeting for the known antivasculature-directed potency of MSA alone in MSA-sensitive tumor models. Resensitization to MSAs was also probed in P glycoprotein-overexpressing SW480-derived tumor xenografts. Different bevacizumab regimens also sensitized this otherwise-resistant tumor model to clinically relevant MSA paclitaxel.. A treatment combination of MSAs with antiangiogenic agents is potent to overcome tumor cell-linked MSA resistance and should be considered as strategy for MSA-refractory tumor entities.

Topics: Adenocarcinoma; Angiogenesis Inhibitors; Animals; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Bevacizumab; Blotting, Western; Cell Line, Tumor; Cell Proliferation; Colonic Neoplasms; Drug Resistance, Neoplasm; Epothilones; Everolimus; Humans; Kaplan-Meier Estimate; Lung Neoplasms; Mice; Mice, Nude; Microtubules; Paclitaxel; Real-Time Polymerase Chain Reaction; RNA, Neoplasm; Sirolimus; TOR Serine-Threonine Kinases; Tubulin Modulators; Vascular Endothelial Growth Factor A; Xenograft Model Antitumor Assays

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

Molecular mechanisms underlying epothilone-induced apoptotic cell death were investigated in SW620 human colon cancer cells. Treatment with epothilone B and D at different concentrations (1-100 nmol/L) dose-dependently inhibited cell growth and caused cell cycle arrest at G2-M, which was followed by apoptosis. Consistent with this induction of apoptotic cell death, epothilone B and D enhanced the constitutional activation of nuclear factor-kappaB (NF-kappaB) via IkappaB degradation through IkappaB kinase (IKKalpha and IKKbeta) activation, and this resulted in p50 and p65 translocation to the nucleus. Moreover, cells treated with sodium salicylic acid, an IKK inhibitor, or transiently transfected with mutant IKKalpha and beta did not show epothilone-induced cell growth inhibition or p50 translocation, although p65 was still translocated to the nucleus. Treatment with epothilone B and D also enhanced beta-tubulin polymerization and the formation of p50/beta-tubulin complex. However, beta-tubulin polymerization was not inhibited in the cells treated by sodium salicylic acid or transiently transfected with mutant IKKalpha and beta. Moreover, epothilone B and D increased the expressions of NF-kappaB-dependent apoptotic cell death regulatory genes, i.e., Bax, p53, and the active form of caspase-3, but reduced Bcl-2 expression, and these actions were partially reversed by salicylic acid. In addition, caspase-3 inhibitor reduced epothilone B-induced cell death and NF-kappaB activation. These findings suggest that the activation of NF-kappaB/IKK signals plays an important role in the epothilone-induced apoptotic cell death of SW620 colon cancer cells in a tubulin polymerization-independent manner.

Topics: Apoptosis; bcl-2-Associated X Protein; Blotting, Western; Caspase 3; Cell Nucleus; Colonic Neoplasms; Electrophoretic Mobility Shift Assay; Epothilones; Flow Cytometry; Fluorescent Antibody Technique; Humans; I-kappa B Kinase; In Situ Nick-End Labeling; Luciferases; Microtubules; NF-kappa B; Protein Transport; Proto-Oncogene Proteins c-bcl-2; Salicylic Acid; Signal Transduction; Tubulin; Tumor Cells, Cultured; Tumor Suppressor Protein p53

Microtubule-damaging agents (MDA) are potent antineoplastic drugs that are widely used in clinical treatment for a variety of cancers. However, the precise mechanisms underlying MDA-induced cell death are largely unknown. Here, we report that both p53 and Bax are central participants in the MDA-mediated cell death machinery in HCT116 human colon cancer cells. MDA, including epothilone B analogue (BMS-247550) and vinblastine, induced apoptosis of Bax-positive HCT116 cells in a p53-dependent manner; p53 was required for MDA-induced Bax conformational change. In response to MDA treatment, the BH3-only proapoptotic protein PUMA was up-regulated in p53-positive but not in p53 knockout HCT116 cells. Moreover, PUMA knockout HCT116 cells were resistant to MDA-induced Bax conformational change and apoptosis. In addition, introducing p53 plasmid DNA into p53-deficient HCT116 cells restored PUMA expression and apoptotic response to MDA treatment. However, ectopic expression of the p53 point mutation L22Q/W23S, but not the proline-rich domain deletion mutants 83-393 and DeltaProAE, could also sensitize p53 knockout HCT116 cells to MDA-induced Bax activation and apoptosis, although all mutants failed to restore PUMA expression. Together, these findings suggest that p53 acts upstream of Bax to promote MDA-mediated cell death in a proline-rich domain-dependent manner through both transcription-dependent (by up-regulating PUMA expression) and -independent mechanisms in human colon cancer HCT116 cells.

Topics: Antineoplastic Agents; Apoptosis; Apoptosis Regulatory Proteins; bcl-2-Associated X Protein; Cell Line, Tumor; Colonic Neoplasms; Epothilones; Gene Deletion; Humans; Microtubules; Mitochondria; Mutagenesis; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Transcription, Genetic; Tumor Suppressor Protein p53

We provide a full account of the discovery of the (E)-9,10-dehydro derivatives of 12,13-desoxyepothilone B (dEpoB), a new class of antitumor agents with promising in vivo preclinical properties. The compounds, which are to date not available by modification of any of the naturally occurring epothilones, were discovered through total chemical synthesis. We describe how our investigations of ring-closing metathesis reactions in epothilone settings led to the first and second generation syntheses of (E)-9,10-dehydro-12,13-desoxyepothilone congener 6. With further modifications, the synthesis was applied to reach a 26-trifluoro derivative compound (see compound 7). To conduct such studies and in anticipation of future development needs, the total synthesis which led to the initial discovery of compound 7 was simplified significantly. The total synthesis methodology used to reach compound 7 was then applied to reach more readily formulated compounds, bearing hydroxy and amino functionality on the 21-position (see compounds 45, 62, and 63). Following extensive in vitro evaluations of these new congeners, compound 7 was nominated for in vivo evaluations in xenograft models. The data provided herein demonstrate a promising therapeutic efficacy, activity against large tumors, nonrelapseability, and oral activity. These results have identified compound 7 as a particularly promising compound for clinical development. The excellent, totally synthetic, route to 7 makes such a program quite feasible.

Topics: Animals; Antineoplastic Agents; Breast Neoplasms; Colonic Neoplasms; Epothilones; Humans; Mice; Mycobacterium; Xenograft Model Antitumor Assays

BMS-247550, a novel epothilone derivative, is being developed by Bristol-Myers Squibb Company (BMS) as an anticancer agent for the treatment of patients with malignant tumors. BMS-247550 is a semisynthetic analogue of the natural product epothilone B and has a mode of action analogous to that of paclitaxel (i.e., microtubule stabilization). In vitro, it is twice as potent as paclitaxel in inducing tubulin polymerization. Like paclitaxel, BMS-247550 is a highly potent cytotoxic agent capable of killing cancer cells at low nanomolar concentrations. Importantly, BMS-247550 retains its antineoplastic activity against human cancers that are naturally insensitive to paclitaxel or that have developed resistance to paclitaxel, both in vitro and in vivo. Tumors for which BMS-247550 demonstrated significant antitumor activity encompass both paclitaxel-sensitive and -refractory categories, i.e., (a) paclitaxel-resistant: HCT116/VM46 colorectal (multidrug resistant), Pat-21 breast and Pat-7 ovarian carcinoma (clinical isolates; mechanisms of resistance not fully known), and A2780Tax ovarian carcinoma (tubulin mutation); (b) paclitaxel-insensitive: Pat-26 human pancreatic carcinoma (clinical isolate) and M5076 murine fibrosarcoma; and (c) paclitaxel sensitive: A2780 ovarian, LS174T, and HCT116 human colon carcinoma. In addition, BMS-247550 is p.o. efficacious against preclinical human tumor xenografts grown in immunocompromised mice or rats. Schedule optimization studies indicate that BMS-247550 is efficacious when administered frequently (every 2 days x 5) or intermittently (every 4 days x 3 or every 8 days x 2). These efficacy data demonstrate that BMS-247550 has the potential to surpass Taxol in both clinical efficacy and ease of use (i.e., less frequent treatment schedule and/or oral administration).

Topics: Administration, Oral; Animals; Antineoplastic Agents; Breast Neoplasms; Cell Cycle; Cell Survival; Colonic Neoplasms; Disease Models, Animal; Drug Resistance, Neoplasm; Epothilones; Epoxy Compounds; Female; Humans; Infusions, Parenteral; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Inbred DBA; Neoplasm Transplantation; Ovarian Neoplasms; Paclitaxel; Pancreatic Neoplasms; Sarcoma; Thiazoles; Tubulin; Tumor Cells, Cultured; Tumor Stem Cell Assay; Xenograft Model Antitumor Assays