NEW YORK – Agendia said yesterday it began a clinical trial to evaluate the safety of discontinuing adjuvant endocrine therapy after two years for patients whose tumors have a MammaPrint "ultra low" result for breast cancer recurrence risk.
The LESS trial will enroll 696 post-menopausal breast cancer patients with hormone receptor-positive, HER2-negative breast cancer at 45 sites within the Unicancer hospital network in France. Participants will receive letrozole, anastrozole, or exemestane. The primary outcome of the trial will be determined by distant metastasis-free survival. Secondary outcomes include invasive disease-free survival, overall survival, and a quality-of-life questionnaire.
Five years of adjuvant endocrine therapy is standard therapy for localized hormone receptor-positive breast cancer with well-stablished benefits in terms of survival and preventing relapse. However, the substantial side effects associated with endocrine therapy also impact quality of life and reduce patient adherence to treatment. Those include hot flashes, night sweats, and vaginal dryness, as well as more serious effects such as blood clots, depression, and increased risk of heart attack.
Agendia has previously reported a study showing that patients with an ultra low risk signature on the 70-gene prognostic test had an eight-year survival rate of 99 percent, specific to breast cancer, and 97 percent were free of distant metastases after eight years.