Abstract OT1-08-07: CONTESSA 2: A multinational, multicenter, phase 2 study of tesetaxel plus a reduced dose of capecitabine in patients with HER2-, HR+ metastatic breast cancer (MBC) who have not previously received a taxane

Abstract

Abstract Background: Chemotherapy treatments with robust efficacy that preserve quality of life are needed. Tesetaxel is a novel, oral taxane that has potential advantages over currently available taxanes, including: oral administration with a low pill burden and once every 3 week (Q3W) dosing; no observed hypersensitivity reactions; preclinical evidence of central nervous system (CNS) penetration; and improved activity against chemotherapy-resistant tumors. More than 600 patients have been treated with tesetaxel in clinical studies. Tesetaxel had robust monotherapy activity in a Phase 2 study in 38 patients with HER2-, HR+ MBC, with a confirmed objective response rate (ORR) per RECIST 1.1 of 45%. Preclinical and clinical studies suggest that reducing the dose of capecitabine in combination with a taxane may result in reduced toxicity without a reduction in efficacy. CONTESSA 2 investigates tesetaxel plus a reduced dose of capecitabine as an all-oral regimen in taxane-naïve patients with HER2-, HR+ MBC. Trial design: CONTESSA 2 is a 125-patient, multinational, multicenter, single-arm, Phase 2 study of tesetaxel (27 mg/m2 on Day 1 of a 21-day cycle) plus a reduced dose of capecitabine (1,650 mg/m2/day for 14 days of each 21-day cycle) in patients with HER2-, HR+ MBC who have received no more than one chemotherapy regimen for advanced disease and have not previously been treated with a taxane in any setting. Patients with CNS metastases are eligible. The primary endpoint is confirmed ORR assessed by an Independent Radiologic Review Committee (IRC). A sample size of 125 will allow the ORR to be estimated with a maximum standard error of < 5%. Secondary endpoints include duration of response, pharmacokinetics (PK) of tesetaxel and potential for a PK interaction between tesetaxel and capecitabine. Enrollment was initiated in January 2019. For further information on this trial, email joconnell@odonate.com or visit clinicaltrials.gov (NCT03858972). Citation Format: Lee Schwartzberg, Jamil Asselah, Igor Bondarenko, YeeSoo Chae, Noshir DaCosta, Yin-Hsun Feng, Yann Izarzugaza, Julie Lemieux, Mei-Ching Liu, Gavin Marx, Joyce O'Shaughnessy, Mafalda Oliveira, Hope Rugo, Andrew Seidman, Gail Wright, Joseph O'Connell, Thomas Wei, Sung-Bae Kim. CONTESSA 2: A multinational, multicenter, phase 2 study of tesetaxel plus a reduced dose of capecitabine in patients with HER2-, HR+ metastatic breast cancer (MBC) who have not previously received a taxane [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr OT1-08-07.