TRANSLATIONAL CORRELATES OF AN EPOTHILONE B ANALOG

The optimum dose, clinical toxicity and antitumor activity of BMS-247550 will be determined in a dose-escalation phase I clinical trial of patients with advanced Taxol-refractory ovarian cancer. We will evaluate the effects of BMS-24755 on its molecular target, the microtubule, specifically beta- tubulin and investigate its role in modulating the expression and function of defined biological markers that regulate drug transport, cytoskeletal integrity and cell death. All results will be correlated with pharmacokinetics, clinicopathology and patient response using univariate and multivariate analyses, and the findings from this pilot study applied to a large-scale study. Tumor biopsies will be harvested from pre- and post- treatment patients, together with malignant fluid, when available. Total RNA, DNA and protein will be isolated from all specimens and stored at 70 centigrade. Correlates of BMS-247550 dose pharmacokinetics with microtubule bundle and aster formation in peripheral blood mononuclear cells (PBMC's ) will be determined. The primary aims of this scientific exploratory study are: 1. To evaluate the relationship between tumor response and (a) the occurrence of mutation in the class I isotype of beta-tubulin and (b) beta- tubulin isotype distribution. Mutations in beta-tubulin have been isolated in Taxol-resistant cancer cell lines, and mutations in the GTP-binding regions of beta-tubulin have been associated with poor response/survival to Taxol monotherapy in NSCLC patients. 2. To investigate MDR1, MRP and cMOAT mRNA and protein expression as prognosticators of tumor response to BMS-247550. 3. To correlate the effects of BMS-247550 on the expression of proteins which regulate apoptosis, such as bcl-2 family members and IAP (inhitors of apoptosis) members, e.g. survivin and p53. Changes in mitochondrial membrane potential, an early indicator of apoptosis, will be evaluated by flow cytometry and compared in pre-and post-treatment tumor samples and correlated with response. 4. To determine the relationship between stathmin expression and phosphorylation status as a function of response.