Ixempra (Ixabepilone) is a new anti-tumor chemotherapeutic agent in the epothilones class that resembles paclitaxel microtubule protein polymerization and inhibits microtubule depolymerization activity, developed and manufactured by Schweppes. In October 2007, the FDA approved Ixempra, alone or in combination with capecitabine, for the treatment of metastatic or locally progressive advanced breast cancer that has failed to respond to anthracycline, paclitaxel derivatives, and capecitabine. Epothilones: A class of macrolides with a sixteen-membered ring, first isolated by Holfe and Reichenbach in 1992 from the species Sorangium cellulosum, Ixabepilone (BMS-247550) is a semi-synthetic epothilone β-lactam analog. Ixabepilone (BMS-247550) is a semi-synthetic epothilone β-lactam analogue, which belongs to a new generation of anti-mitotic drugs. Its mechanism of action is similar to that of paclitaxel-like drugs (taxanes), which can bind to microtubulin to cause cancer cells to fail to undergo mitosis smoothly and then cause apoptosis of cancer cells, and is superior to paclitaxel in terms of anti-tumor spectrum, anti-tumor activity, safety, water solubility and synthesis method. Ixempra is the first new anti-tumor drug of the ebolycin class, which can bind to microtubule proteins and cause cancer cells to fail mitosis and eventually apoptosis. Ixempra has a new chemical structure with different microtubule binding sites than paclitaxel, and thus has stronger anti-tumor activity. Moreover, Ixempra has low susceptibility to tumor resistance mechanism. 1. Ixempra monotherapy In a phase II clinical trial of Ixempra monotherapy for anthracycline, paclitaxel and capecitabine-resistant metastatic breast cancer, breast cancer patients were treated with intravenous infusion of Ixempra 40mg/m23 hours every 3 weeks for 1 course until disease progression (PD). The results showed an ORR of 11,5%, a disease stabilization (SD) rate of 50,0%, and a median progression-free survival (PFS) of 3,1 months in 113 evaluable patients. The highest incidence of neutropenia (54%) was observed among grade 3-4 toxic reactions, and other peripheral neurotoxicity, weakness, myalgia, and mucositis were also seen. 2. Ixempra combination therapy The CA163046 study was a randomized phase III clinical trial. The study included 752 patients with metastatic or locally advanced breast cancer resistant to anthracyclines and paclitaxel. Patients were randomized to the combination therapy group (n=375) and the monotherapy group (n=377), receiving Ixempra (40 mg/m2, IV infusion >3 hours, d1, q3w) + capecitabine (2000 mg/m2 daily in 2 oral doses, d1 to d14, q3w) or capecitabine monotherapy (2500 mg/m2 daily in 2 orally, d1 to d14, q3w). The investigators strictly defined prior treatment resistance: metastatic breast cancer with rapid tumor progression after receiving adjuvant chemotherapy with anthracyclines and paclitaxel or treatment for metastatic disease. The primary endpoint of the study was PFS [assessed using blinded independent radiographic evaluation (IRR)]; secondary endpoints were ORR, time to remission, duration of remission, and overall survival (OS). The results showed that the baseline characteristics of the two groups were similar in terms of age, KPS score, previous treatment regimen for metastatic disease, and previous treatment received, and were comparable. In addition, disease and tumor characteristics such as number of lesions, visceral metastases, hormone receptor status, and Her-2 status were similar in both groups. Based on IRR assessment, the ORR of the two groups was 35% and 14%, respectively (P