Explaining PFS2 in the MONALEESA-7 Trial for HR+/HER2- Breast Cancer

Debu Tripathy, MD, of the Department of Breast Medical Oncology, Division of Cancer Medicine, MD Anderson Cancer Center, was an investigator in thephase III MONALEESA-7 trial. The purpose of the study was to examine how endocrine therapy, in combination with a cyclin-dependent kinase (CDK) inhibitor, affects progression-free survival and overall survival in premenopausal patients with HR-positive, HER2-negative advanced breast cancer.

In the trial, 672 premenopausal female patients under 59 years of age, who had never received endocrine therapy prior, were randomized 1:1 to either ribociclib (Kisqali) or placebo, both with endocrine therapy.

Following treatment with the endocrine therapy and CDK4/6 inhibitor combination, patients who progressed then went on to receive other treatment. These therapies included chemotherapy alone, hormone therapy alone, chemotherapy plus hormone or other therapy—such as biologics including everolimus, or hormone therapy plus other treatment. For these patients, progression-free survival 2, or the time from randomization to progression on second-line therapy or death, was measured.