Odonate Therapeutics, Inc. announced positive top-line results from CONTESSA, a Phase 3 study of tesetaxel in patients with metastatic breast cancer (MBC). CONTESSA is a multinational, multicenter, randomized, Phase 3 study of tesetaxel, an investigational, orally administered taxane, in patients with MBC. CONTESSA is comparing tesetaxel dosed orally at 27 mg/m2 on the first day of each 21-day cycle plus a reduced dose of capecitabine (1,650 mg/m2/day dosed orally for 14 days of each 21-day cycle) to the approved dose of capecitabine alone (2,500 mg/m2/day dosed orally for 14 days of each 21-day cycle) in 685 patients randomized 1:1 with human epidermal growth factor receptor 2 (HER2) negative, hormone receptor (HR) positive MBC previously treated with a taxane in the neoadjuvant or adjuvant setting. Capecitabine is an oral chemotherapy agent that is considered a standard-of-care treatment in MBC. Where indicated, patients must have received endocrine therapy with or without a cyclin-dependent kinase (CDK) 4/6 inhibitor. The primary endpoint is progression-free survival (PFS) as assessed by the Independent Radiologic Review Committee (IRC). The secondary efficacy endpoints are overall survival (OS), objective response rate (ORR) as assessed by the IRC and disease control rate (DCR) as assessed by the IRC. CONTESSA is being conducted at 180 investigational sites in 18 countries in North America, Europe and Asia. CONTESSA met the primary endpoint of improved PFS as assessed by the IRC. Median PFS was 9.8 months for tesetaxel plus a reduced dose of capecitabine versus 6.9 months for the approved dose of capecitabine alone, an improvement of 2.9 months. The risk of disease progression or death was reduced by 28.4% [hazard ratio=0.716 (95% confidence interval: 0.573-0.895); p=0.003] for tesetaxel plus a reduced dose of capecitabine versus the approved dose of capecitabine alone. Tesetaxel plus capecitabine was associated with a manageable side effect profile consistent with findings from previous clinical studies. Grade =3 treatment-emergent adverse events (TEAEs) that occurred in =5% of patients were: neutropenia (71.2% for tesetaxel plus capecitabine vs. 8.3% for capecitabine alone); diarrhea (13.4% for tesetaxel plus capecitabine vs. 8.9% for capecitabine alone); hand-foot syndrome (6.8% for tesetaxel plus capecitabine vs. 12.2% for capecitabine alone); febrile neutropenia (12.8% for tesetaxel plus capecitabine vs. 1.2% for capecitabine alone); fatigue (8.6% for tesetaxel plus capecitabine vs. 4.5% for capecitabine alone); hypokalemia (8.6% for tesetaxel plus capecitabine vs. 2.7% for capecitabine alone); leukopenia (10.1% for tesetaxel plus capecitabine vs. 0.9% for capecitabine alone); and anemia (8.0% for tesetaxel plus capecitabine vs. 2.1% for capecitabine alone). Adverse events resulting in treatment discontinuation in =1% of patients were: neutropenia or febrile neutropenia (4.2% for tesetaxel plus capecitabine vs. 1.5% for capecitabine alone); neuropathy (3.6% for tesetaxel plus capecitabine vs. 0.3% for capecitabine alone); diarrhea (0.9% for tesetaxel plus capecitabine vs. 1.5% for capecitabine alone); and hand-foot syndrome (0.6% for tesetaxel plus capecitabine vs. 2.1% for capecitabine alone). Treatment discontinuation due to any adverse event occurred in 23.1% of patients treated with tesetaxel plus capecitabine versus 11.9% of patients treated with capecitabine alone. Grade 2 alopecia (hair loss) occurred in 8.0% of patients treated with tesetaxel plus capecitabine versus 0.3% of patients treated with capecitabine alone. Grade =3 neuropathy occurred in 5.9% of patients treated with tesetaxel plus capecitabine versus 0.9% of patients treated with capecitabine alone. While overall survival (OS) data are not mature, a recent interim analysis indicated the absence of an adverse effect on OS. A final analysis of OS is expected to occur in 2022.