Novel Chemotherapy Agent Improves PFS in Metastatic Breast Cancer

Treatment with tesetaxel in combination with capecitabine led to an improvement in progression-free survival (PFS) as treatment of patients with metastatic breast cancer compared with single-agent capecitabine, meeting the primary end point of the phase 3 CONTESSA study, Odonate Therapeutics announced in a press release.

“Tesetaxel represents a potential important clinical advance for patients with metastatic breast cancer,” said Joyce O’Shaughnessy, MD, 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, in a statement. “There remains a significant unmet medical need for novel therapies that offer quality-of-life advantages for patients with metastatic breast cancer. This need is underscored by a recent update to the National Comprehensive Cancer Network guidelines recommending oral oncolytics that can reduce the frequency of clinic visits.”

There was a 2.9-month improvement in the median PFS with the tesetaxel combination, which demonstrated a median PFS of 9.8 months versus 6.9 months with capecitabine alone. The reduction in the risk of disease progression or death with tesetaxel plus capecitabine versus capecitabine alone was 28.4% (HR, 0.716; 95% CI, 0.573-0.895; P =.003).

“The clinically meaningful PFS improvement observed in CONTESSA, along with once-every-three-week oral dosing and low rates of clinically significant hair loss and neuropathy, could make tesetaxel an important new treatment option for patients with metastatic breast cancer,” stated Andrew Seidman, MD, attending physician, Breast Medicine Service, Department of Medicine, Medical Director, Bobst International Center, Memorial Sloan Kettering Cancer Center and Professor of Medicine, Weill Cornell Medical College, and Co-Principal Investigator of CONTESSA.

Tesetaxel also showed a tolerable safety profile, which was consistent with the toxicities reported in previous studies. Five percent of patients in the study experienced treatment-emergent adverse events (TEAEs). The TEAEs observed in the combination arm versus the capecitabine monotherapy arm were neutropenia (71.2% vs. 8.3%) diarrhea (13.4% vs. 8.9%), hand-foot syndrome (6.8% vs. 12.2%) febrile neutropenia (12.8% vs. 1.2%), fatigue (8.6% vs. 4.5%, hypokalemia (8.6% vs. 2.7%) leukopenia (10.1% vs. 0.9%), and anemia (8.0% vs. 2.1%).

In the tesetaxel plus capecitabine arm, 23.1% of patients discontinued treatment due to a TEAE as did 11.9% of those in the capecitabine monotherapy arm.

Cases of grade 2 alopecia were observed in 8.0% of the patients who received the tesetaxel combination compared with 0.3% of those who received capecitabine alone. In addition, grade 3 or higher neuropathy was seen in 5.9% of the tesetaxel versus 0.9% of the capecitabine arm.

It was noted that the overall survival data in this study have not yet matured, but a recent interim analysis did reveal that the AEs observed in the study had no impact on OS. The final OS data will prospectively be analyzed in 2022.

CONTESSA is an ongoing international, multicenter, randomized, phase 3 study of 685 patients with metastatic breast cancer who are randomized 1:1. In the study, tesetaxel is administered orally at 27 mg/m2 on the first day of each 21-day cycle. Reduced-dose capecitabine is given orally at 1,650 mg/m2 per day dosed orally for 14 days of each 21-day cycle. In the capecitabine monotherapy arm, the chemotherapy agent is administered at the FDA approved dose of 2,500 mg/m2/day dosed orally for 14 days of each 21-day cycle.

In addition to the PFS, OS, objective response rate, and disease control were explored in CONTESSA as secondary end points.

Tesetaxel is an investigational chemotherapy drug. It is currently being evaluated as treatment of breast cancer in multiple phase 2 and 3 clinical trials.

_Reference:

_{Odonate Therapeutics announces positive top-line results from contessa, a phase 3 study of tesetaxel in patients with metastatic breast cancer. News release. Odonate Therapeutics. August 24, 2020. Accessed August 25, 2020. https://bwnews.pr/3hrpzGI}