Odonate Therapeutics, Inc. announced that positive results from CONTESSA, a Phase 3 study of tesetaxel in patients with metastatic breast cancer (MBC), were presented in an oral presentation at the 2020 San Antonio Breast Cancer Symposium (SABCS). The results were presented by Joyce O’Shaughnessy, M.D., Celebrating Women Chair in Breast Cancer Research, Baylor University Medical Center, Texas Oncology and Chair, Breast Cancer Research, US Oncology, and Co-Principal Investigator of CONTESSA (please click here for slides). 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 hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative 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. The ORR as assessed by the IRC was 57% for tesetaxel plus a reduced dose of capecitabine versus 41% for the approved dose of capecitabine alone (p=0.0002). The DCR as assessed by the IRC was 67% for tesetaxel plus a reduced dose of capecitabine versus 50% for the approved dose of capecitabine alone (p<0.0001). While OS data are immature, a recent interim analysis indicated the absence of an adverse effect on OS with tesetaxel plus a reduced dose of capecitabine. A protocol-specified final analysis of OS is expected to occur in 2022. 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 (70.9% for tesetaxel plus capecitabine vs. 8.3% for capecitabine alone); diarrhea (13.1% 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 (13.1% 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 (9.8% for tesetaxel plus capecitabine vs. 0.9% for capecitabine alone); and anemia (8.0% for tesetaxel plus capecitabine vs. 2.4% for capecitabine alone).