Effect of food on the pharmacokinetic behavior of the potent oral taxane BMS-275183.

PURPOSE: BMS-275183 is a potent oral paclitaxel analogue that previously showed promising activity. The goal of the present trial was to investigate whether food affects the pharmacokinetics of BMS-275183. Additionally, we evaluated its pharmacokinetic variability using flat-fixed dosing compared with dosing individualized by body surface area (BSA). PATIENTS AND METHODS: The patients were treated with 200 mg of BMS-275183 under fasting condition (A), after a standard low-fat meal (B), or after a high-fat meal (C). The patients were randomized to one of six treatment sequences (ABC, ACB, BAC, BCA, CAB, or CBA). The fourth (D) and consecutive weekly doses were normalized by BSA and consisted of 200 mg/m(2). Pharmacokinetic sampling was done up to 72 hours after the first four doses and analyzed with a validated liquid chromatography/mass spectrometry assay. RESULTS: A total of 31 patients were treated. Pharmacokinetic data were available for 26 patients (A and C), 24 patients (B), and 21 patients (D). Compared with administration under fasted conditions, a decrease of 39% and 63% in the maximal observed drug concentration was observed when BMS-275183 was administered after a low-fat and a high-fat meal, respectively. There was no change in systemic exposure as measured by the area under the plasma concentration versus time curve extrapolated to infinity (AUC(inf)). No apparent relationship was observed between AUC(inf) and BSA for either the 200 mg or the 200 mg/m(2) regimen. BMS-275183 was well tolerated with grade 3 and 4 toxicity in eight patients. One partial response was observed in a non-small cell lung cancer patient. CONCLUSIONS: Food intake does not affect the pharmacologic exposure to BMS-275183. BMS-275183 can be given orally by flat dosing instead of BSA-normalized dosing.

A phase I safety and pharmacologic study of a twice weekly dosing regimen of the oral taxane BMS-275183.

PURPOSE: BMS-275183, an orally administered C-4 methyl carbonate paclitaxel analogue, showed promising activity in a phase I trial investigating a weekly treatment regimen, but was associated with a relatively high incidence of neuropathic side effects. The current dose escalation phase I trial was initiated to investigate whether twice weekly administration of BMS-275183 would improve its safety and tolerability. Additionally, the pharmacokinetics and possible antitumor activity were studied. EXPERIMENTAL DESIGN: A cycle consisted of 4 weeks (i.e., eight twice weekly oral doses). The starting dose was 60 mg/m(2) and the dose was increased by 20 mg/m(2) increments. Cohorts consisted of three patients and were expanded to at least six patients when toxicity was encountered. Plasma pharmacokinetics were done on days 1 and 15. RESULTS: A total of 38 patients were enrolled. The maximum tolerated dose was 100 mg/m(2) twice weekly. Seventeen patients were treated at the maximum tolerated dose; 3 of 17 patients experienced a dose-limiting toxicity, consisting of a combination of neutropenia, neuropathy, and diarrhea. BMS-275183 seemed to have a considerably lower incidence of neuropathic side effects compared with the weekly treatment regimen. Confirmed partial responses were observed in two patients with non-small cell lung cancer, one patient with prostate cancer, and one patient with melanoma. In addition, a long-lasting prostate-specific antigen response was observed in a patient with prostate carcinoma with nonmeasurable disease. CONCLUSIONS: BMS-275183 is preferably given in a twice weekly regimen and has considerable antitumor activity. A phase II trial in non-small cell lung cancer using the twice weekly schedule has been initiated.

Phase I trial with BMS-275183, a novel oral taxane with promising antitumor activity.

PURPOSE: BMS-275183 is an orally administered C-4 methyl carbonate analogue of paclitaxel. We did a dose-escalating phase I study to investigate its safety, tolerability, pharmacokinetics, and possible antitumor activity. EXPERIMENTAL DESIGN: A cycle consisted of four weekly doses of BMS-275183. The starting dose was 5 mg, which was increased by 100% increments (i.e., 5, 10, 20 mg/m2, etc.) in each new cohort consisting of one patient. Cohorts were expanded when toxicity was encountered, and 20 patients were treated at the maximum tolerated dose (MTD). Plasma pharmacokinetics were done on days 1 and 15. RESULTS: A total of 48 patients were enrolled in this trial. Dose-limiting toxicities consisted of neuropathy, fatigue, diarrhea, and neutropenia. First cycle severe neuropathy was reported in four patients treated at 320 (n = 1), 240 (n = 2), and 160 mg/m2 (n = 1), whereas eight patients treated at dose levels ranging from 160 to 320 mg/m2 experienced grade 2 neuropathy in cycle one. The MTD was 200 mg/m2, as 3 of 20 patients experienced grade 3 or 4 toxicity in cycle one [fatigue (n = 2), and neutropenia/diarrhea (n = 1)]. BMS-275183 was rapidly absorbed with a mean plasma half-life of 22 hours. We observed a significant correlation between drug-exposure and toxicity. Tumor responses were observed in 9 of 38 evaluable patients with non-small cell lung cancer, prostate carcinoma, and other tumor types. CONCLUSIONS: BMS-275183 is generally well tolerated on a weekly schedule. The main toxicity is peripheral neuropathy, and the MTD is 200 mg/m2. Promising activity was observed in several tumor types, and a phase II trial in non-small cell lung cancer has been initiated.

Cell death independent of caspases: a review.

Patterns of cell death have been divided into apoptosis, which is actively executed by specific proteases, the caspases, and accidental necrosis. However, there is now accumulating evidence indicating that cell death can occur in a programmed fashion but in complete absence and independent of caspase activation. Alternative models of programmed cell death (PCD) have therefore been proposed, including autophagy, paraptosis, mitotic catastrophe, and the descriptive model of apoptosis-like and necrosis-like PCD. Caspase-independent cell death pathways are important safeguard mechanisms to protect the organism against unwanted and potential harmful cells when caspase-mediated routes fail but can also be triggered in response to cytotoxic agents or other death stimuli. As in apoptosis, the mitochondrion can play a key role but also other organelles such as lysosomes and the endoplasmic reticulum have an important function in the release and activation of death factors such as cathepsins, calpains, and other proteases. Here we review the various models of PCD and their death pathways at molecular and organelle level and discuss the relevance of the growing knowledge of caspase-independent cell death pathways for cancer.

Cathepsin B mediates caspase-independent cell death induced by microtubule stabilizing agents in non-small cell lung cancer cells.

We have previously reported that the microtubule stabilizing agents (MSAs) paclitaxel, epothilone B and discodermolide induce caspase-independent cell death in non-small cell lung cancer (NSCLC) cells. Here we present two lines of evidence indicating a central role for the lysosomal protease cathepsin B in mediating cell death. First, inhibition of cathepsin B, and not of caspases or other proteases, such as cathepsin D or calpains, results in a strong protection against drug-induced cell death in several NSCLC cells. Second, MSAs trigger disruption of lysosomes and release and activation of cathepsin B. Interestingly, inhibition of cathepsin B prevents the appearance of multinucleated cells, an early characteristic of MSA-induced cell death, pointing to a central, proximal role for cathepsin B in this novel cell death pathway.

The role of new agents in the treatment of non-small cell lung cancer.

Lung cancer is one of the most frequent causes of cancer deaths worldwide. Non-small cell lung cancer (NSCLC) accounts for approximately 80% of cases and no curative treatment is available for the advanced stages of disease (stages III and IV), which comprise the majority of cases. Current treatment regimens with standard chemotherapy offer only a limited survival benefit, and, therefore, the development of new therapeutic strategies is needed. Novel chemotherapeutic drugs such as the epothilones, MEN 10755 and S-1 are being studied in patients with advanced stages of disease. Furthermore, a large number of therapies targeted against critical biological abnormalities in NSCLC are being investigated in clinical trials. The latter approach includes inhibition of growth factors, interference with abnormal signal transduction, inhibition of angiogenesis and gene replacement therapy. Promising results have thus far been obtained with some of these therapies. This review describes the role of new therapeutic agents in the treatment of NSCLC.

Late activation of apoptotic pathways plays a negligible role in mediating the cytotoxic effects of discodermolide and epothilone B in non-small cell lung cancer cells.

Discodermolide and epothilone B are promising novel chemotherapeutic agentsthat induce cell death through potent stabilization of microtubules. In this study, we investigated the cellular and molecular events underlying the cytotoxicity of these drugs in non-small cell lung carcinoma (NSCLC) cell lines, focusing on apoptotic characteristics. IC80 concentrations of either drug effectively disrupted the microtubule cytoskeleton of H460 cells and induced cell cycle disturbances with early accumulation in the G2-M phase and development of a hypodiploid cell population in both H460 and SW1573 cells. These events were followed by abnormal chromosome segregation during mitosis and subsequent appearance of multinucleated cells. At later time points, the cells displayed several apoptotic features, such as nuclear condensation and fragmentation as well as Annexin V staining, cleavage of poly(ADP-ribose) polymerase and the activation of caspases. To examine the contribution of apoptotic pathways to the cytotoxic effects of these agents, the involvement of the mitochondria and death receptor routes was studied. At 48 h after treatment, both agents disrupted mitochondria of H460 cells, as indicated by cytochrome c release. Nonetheless, H460 cells stably overexpressing antiapoptotic Bcl-2 or Bcl-xL did not show any protective effect from cell death induced by either drug. Possible death receptor dependency was investigated in H460 cells stably overexpressing dominant-negative FADD, which failed to reduce the cytotoxic effects of discodermolide and epothilone B. To study the role of caspases more directly, the effect of stable overexpression of the caspase-8 inhibitor cytokine response modifier A was studied in H460 cells. Furthermore, the effect of the pancaspase inhibitor z-Val-Ala-Asp-fluoromethyl ketone was investigated in a panel of lung carcinoma cell lines. Interestingly, caspase inhibition did not rescue cells from discodermolide or epothilone B-induced cell death. In conclusion, these results demonstrate that despite several apoptotic features detected at relatively late time points after drug exposure, apoptosis is not the dominant mode of cell death and induced low but efficacious concentrations of discodermolide and epothilone B.

Paclitaxel triggers cell death primarily via caspase-independent routes in the non-small cell lung cancer cell line NCI-H460.

PURPOSE: Here we report on the role of mitochondria, death receptors (DRs), and caspases in exerting the cytotoxic effect of clinically relevant concentrations of paclitaxel in the non-small cell lung cancer cell line NCI-H460. EXPERIMENTAL DESIGN: We have characterized paclitaxel-induced cell death with annexin V, propidium iodide staining, and poly(ADP-ribose) polymerase cleavage assays. The involvement of the mitochondria pathway was studied by monitoring cytochrome c release and using H460 cells stable in overexpressing Bcl-2 or Bcl-x(L). DR dependency was analyzed in FADD dominant-negative or cytokine response modifier A-overexpressing cells, and a possible role for DR4 and DR5 was investigated by antagonistic antibodies. Caspase activity and cleavage assays and treatment with the synthetic inhibitor zVAD-fmk were used to determine the involvement of caspases. RESULTS: Paclitaxel-treated cells displayed several features of apoptosis, including annexin V staining and poly(ADP-ribose) polymerase cleavage. The sequence of events suggested the involvement of a DR, as indicated by an early role for Fas-associated death domain and caspase-8, followed by cleavage of Bid and the disruption of mitochondria; nonetheless, we failed to demonstrate the involvement of DR4 and DR5. Interestingly, inhibition of either one of these routes only resulted in a 30% reduction of cell death that was in line with the observed small effect of caspase inhibition by zVAD-fmk on H460 cell survival. CONCLUSION: Paclitaxel triggers cell death in H460 cells mainly via a currently unidentified caspase-independent mechanism in which the basic apoptotic machinery is merely coactivated. This finding is in sharp contrast with the largely caspase-dependent response elicited by DNA-damaging agents in these cells. We speculate on therapeutic implications.