Sherry Yang

PURPOSE: Ixabepilone is an epothilone B analog that binds to microtubules and results in microtubule stabilization and mitotic arrest. Ixabepilone was evaluated for efficacy and safety in a phase II clinical trial for women with metastatic breast cancer. PATIENTS AND METHODS: Patients were eligible if they had not previously received treatment with a taxane and had measurable metastatic breast cancer. Ixabepilone was administered at 6 mg/m(2)/d intravenously days 1 through 5 every 3 weeks until unacceptable toxicity or disease progression. Patients underwent pretreatment and post-treatment tumor biopsies, and tissues were analyzed for acetylated alpha-tubulin, tau-1, and p53 expression when possible. RESULTS: Twenty-three patients received 210 cycles with a median of eight cycles (range, two to 22 cycles) per patient. Thirteen patients (57%; exact 95% CI, 34.5% to 76.8%) had partial responses, six patients (26%) had stable disease, and four patients (17%) had progressive disease. Median time to progression and duration of response were 5.5 and 5.6 months, respectively. Four patients required dose reductions for neutropenia, neuropathy, or fatigue. Grade 3 or 4 toxicities included neutropenia (22%), fatigue (13%), anorexia (9%), and motor neuropathy (4%). Thirty-nine percent of patients experienced grade 1, 13% experienced grade 2, and none experienced grade 3/4 sensory neuropathy. The six patients with paired biopsies all had increases in tumor alpha-tubulin acetylation after treatment. Baseline or cycle 2 acetylated alpha-tubulin, tau-1, or p53 expression did not correlate with clinical response. CONCLUSION: Women with metastatic breast cancer previously untreated with taxanes have a meaningful durable response to single-agent ixabepilone therapy. Minimal hematologic toxicity and no grade 3 sensory neuropathy were noted.

PURPOSE: To determine the maximum-tolerated dose (MTD) and toxicity profile of the novel anticancer agent, 2-methoxyestradiol (2ME2) administered orally, in patients with solid tumors. MATERIALS AND METHODS: Twenty patients with refractory solid tumors were enrolled. 2ME2 was given orally starting at 400 mg bid with dose escalation until 3000 mg bid. Tumor biopsies were taken before and after starting the drug to assess for microvessel density by CD 31 and cell proliferation by Ki67 immunohistochemistry. Serial plasma samples collected up to 50 hours after first single oral dose for characterization of pharmacokinetics, were analyzed using liquid chromatography tandem mass-spectrometry. RESULTS: Eleven men and nine women received 2ME2 at dose levels of 400 mg bid (n = 3), 800 mg bid (n = 3), 1600 mg bid (n = 6), 2200 mg bid (n = 5) and 3000 mg bid (n = 3). There were no dose limiting toxicities, therefore the MTD was not defined. There was one episode of grade 4 angioedema in the 1600 mg bid dose level 38 days into 2ME2 treatment. Other toxicities were mild to moderate. A patient with clear cell carcinoma of the ovary had a partial response at 1600 mg bid dose level lasting over three years. CONCLUSION: MTD for 2ME2 was not reached at dose of 3000 mg bid. The trial was closed due to extremely low plasma concentrations of 2ME2 relative to the doses administered. 2ME2 treatment had no effect on microvessel density (CD31 immunostaining) and cell proliferation (Ki-67 immunostaining). A new formulation of 2ME2 with improved bioavailability is currently being developed.

PURPOSE: To identify biomarkers and gene expression profile signatures to distinguish patients with partial response (PR) from those with stable disease (SD) and progressive disease (PD). EXPERIMENTAL DESIGN: Twenty patients with inflammatory breast cancer and one patient with locally advanced breast cancer received one cycle of bevacizumab followed by six cycles of bevacizumab plus docetaxel-doxorubicin before surgery. Baseline angiogenic/tumor markers were examined by immunohistochemistry and gene expression profiles were measured by Agilent Whole Human Genome arrays. All were assessed for clinical response. RESULTS: Fourteen patients (67%, 95% confidence interval, 43-85.4%) had PR, five had SD, and two had PD. Expression of CD31 and platelet-derived growth factor receptor-beta (PDGFR-beta) in the tumor vasculature by immunohistochemistry was significantly associated with response (PR versus SD/PD; CD31 median, 33.5 versus 13.2; P = 0.0004; PDGFR-beta median, 5.9 versus 0.6; P = 0.01). Tumor VEGF-A showed a trend towards association with response (2.65 versus 0.25; P = 0.04). pVEGFR2(Y996), pVEGFR2(Y951), MVD, Ki67, apoptosis, grade, ER, HER-2/neu, and p53 were not associated with response. Twenty-six of 1,339 Gene Ontology (GO) classes at the gene transcriptional level were differentially expressed between patients with PR and SD/PD (P < 0.005). Representative significant GO classes include spindle (11 genes; P = 0.001), vascular endothelial growth factor receptor activity including PDGFR-beta (5 genes; P = 0.002), and cell motility including CD31 (80 genes; P = 0.005). CONCLUSIONS: Baseline CD31, PDGFR-beta, and GO classes for vascular endothelial growth factor receptor activity and mitosis were significantly associated with response to bevacizumab followed by bevacizumab plus chemotherapy.