Tesetaxel, Administered Orally as a Single Agent, Results in 45% Confirmed Response Rate in Patients with HER2 Negative, Hormone Receptor Positive, Metastatic Breast Cancer

CHICAGO--(BUSINESS WIRE)-- Odonate Therapeutics, Inc. (NASDAQ: ODT), a pharmaceutical company dedicated to the development of best-in-class therapeutics that improve and extend the lives of patients with cancer, today announced that results from a multicenter Phase 2 study of tesetaxel, administered orally as a single agent to patients with HER2 negative, hormone receptor (HR) positive, metastatic breast cancer (MBC), were presented at the 2018 ASCO Annual Meeting in Chicago, Illinois (Poster Board #123; Abstract #1042).

In this Phase 2 study (Study TOB203), 38 patients with HER2 negative, HR positive, MBC received tesetaxel orally as a single agent once every 3 weeks (Q3W) at a starting dose of 27 mg/m². Eighty-seven percent (87%) had visceral disease, 74% previously received at least one endocrine therapy, 68% previously received neoadjuvant or adjuvant chemotherapy and 53% previously received a taxane-containing regimen. Objective response rate (ORR) based on Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 with confirmation no less than 4 weeks after initial response was the primary endpoint.

In all 38 patients, the confirmed response rate was 45%. The confirmed response rate was consistent across subgroups. Forty-four percent (44%) of patients who did not previously receive a taxane-containing regimen achieved a confirmed response, compared to 45% of patients who previously received a taxane-containing regimen. Median duration of response was 10.9 months, and median progression-free survival was 5.4 months.

Neutropenia was the most common Grade ≥3 adverse event and occurred in 25% of the 24 patients who were not dose-escalated beyond the 27 mg/m² starting dose (the dose selected for CONTESSA, our ongoing Phase 3 study (Poster Board #184a; Abstract #TPS1106); in these patients, febrile neutropenia occurred in 1 patient (4%) and Grade ≥3 neuropathy occurred in 1 patient (4%). There were no hypersensitivity reactions or drug-related deaths, and the rate of Grade 2 alopecia (hair loss) was 18%.

“Despite recent advances in the treatment of advanced breast cancer, there remains a significant need for new therapies that allow patients to maintain a better quality of life,” said 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.

“Tesetaxel’s significant single-agent activity, once-every-three-week oral dosing and low rates of neuropathy and hair loss could make this investigational agent a unique treatment option for patients, if approved,” said Andrew Seidman, M.D., Attending Physician and Associate Chair, Academic Administration, Department of Medicine, Memorial Sloan Kettering Cancer Center (MSKCC) and Professor of Medicine, Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medical College. “We look forward to further characterizing tesetaxel’s therapeutic profile in CONTESSA, an ongoing Phase 3 study.”

About Tesetaxel

Tesetaxel is an investigational, orally administered chemotherapy agent that belongs to a class of drugs known as taxanes, which are widely used in the treatment of cancer. Tesetaxel has several potential therapeutic advantages over currently available taxanes, including: oral administration with a low pill burden and a patient-friendly dosing regimen; no history of hypersensitivity (allergic) reactions; and significant activity against chemotherapy-resistant tumors. More than 500 patients have been treated with tesetaxel in clinical studies. In patients with metastatic breast cancer, tesetaxel was shown to have significant, single-agent antitumor activity in two, multicenter, Phase 2 studies.

About CONTESSA

CONTESSA is a multinational, multicenter, randomized, Phase 3 study of tesetaxel, an investigational, orally administered taxane, in patients with locally advanced or metastatic breast cancer (LA/MBC). CONTESSA is comparing tesetaxel dosed orally at 27 mg/m² on the first day of a 21-day cycle plus a reduced dose of capecitabine (1,650 mg/m²/day dosed orally on days 1-14 of a 21-day cycle) to the approved dose of capecitabine alone (2,500 mg/m²/day dosed orally on days 1-14 of a 21-day cycle) in approximately 600 patients randomized 1:1 with HER2 negative, hormone receptor (HR) positive LA/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 LA/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) assessed by an Independent Radiologic Review Committee (IRC). CONTESSA’s secondary efficacy endpoints are overall survival, objective response rate (ORR) assessed by IRC and disease control rate assessed by IRC. To learn more, please visit www.contessastudy.com.

About Odonate Therapeutics, Inc.

Odonate Therapeutics, Inc. is a pharmaceutical company dedicated to the development of best-in-class therapeutics that improve and extend the lives of patients with cancer. Odonate’s initial focus is on the development of tesetaxel, an investigational, orally administered chemotherapy agent belonging to a class of drugs known as taxanes, which are widely used in the treatment of cancer. Odonate recently initiated CONTESSA, a multinational, multicenter, randomized, Phase 3 study of tesetaxel in patients with locally advanced or metastatic breast cancer. Odonate’s goal for tesetaxel is to develop an effective chemotherapy choice for patients that provides quality-of-life advantages over current alternatives. To learn more, please visit www.odonate.com.

Forward-looking Statements

This press release contains "forward-looking statements" as defined by the Private Securities Litigation Reform Act of 1995. We caution investors that forward-looking statements are based on management’s expectations and assumptions as of the date of this press release and involve substantial risks and uncertainties that could cause the actual outcomes to differ materially from what we currently expect. These risks and uncertainties include, but are not limited to, those associated with: the outcome of CONTESSA, our Phase 3 study of tesetaxel in patients with locally advanced or metastatic breast cancer; our ability to obtain regulatory approval of tesetaxel; and other risks and uncertainties identified in our filings with the United States Securities and Exchange Commission. Forward-looking statements in this press release apply only as of the date made, and we undertake no obligation to update or revise any forward-looking statements to reflect subsequent events or circumstances.

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