Ribociclib plus fulvestrant improves PFS for advanced breast cancer
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CHICAGO — The addition of ribociclib to fulvestrant significantly improved PFS in women with hormone receptor-positive, HER-2-negative advanced breast cancer, irrespective of prior endocrine therapy for advanced disease, according to results of the phase 3 MONALEESA-3 trial presented at the ASCO Annual Meeting.
The data were simultaneously published in Journal of Clinical Oncology.
“In the phase 3 MONALEESA-2 and MONALEESA-7 trials, the addition of ribociclib [Kisqali, Novartis] to endocrine therapy significantly improved PFS compared with placebo plus endocrine therapy in pre-, peri- and postmenopausal women with HR-positive, HER-2-negative advanced breast cancer,” Dennis J . Slamon, MD , PhD, director of clinical/translational research and also director of the Revlon/UCLA Women's Cancer Research Program at UCLA Jonsson Comprehensive Cancer Center, said during his presentation.
“Moreover, CDK4/6 inhibitor and fulvestrant [Faslodex, AstraZeneca] combinations have demonstrated efficacy in patients with hormone receptor-positive breast cancer that has progressed on prior endocrine therapy,” he said. “However, no study had evaluated CDK4/6 inhibitor and fulvestrant combinations in patients with de novo hormone receptor-positive, HER-2-negative advanced breast cancer or in patients who have relapsed more than 1 year after prior endocrine therapy with no subsequent treatment for advanced disease. Until now.”
Slamon and colleagues randomly assigned 726 postmenopausal women in a 2:1 fashion to 600 mg daily ribociclib for 3 weeks on, 1 week off plus 500 mg fulvestrant (n = 484) or placebo plus fulvestrant (n = 242).
PFS served as the study’s primary outcome; secondary outcomes included OS, ORR and safety.
Median duration from randomization to data cutoff was 20.4 months.
Results showed a significant improvement in median PFS with ribociclib (20.5 months vs. 12.8 months; HR = 0.59; 95% CI, 0.48-0.73).
Researchers observed the same treatment effects among women who were treatment naive in the advanced setting (HR = 0.57; 95% CI, 0.41-0.8), and among those treated with up to one line of prior endocrine therapy for advanced disease (HR = 0.56; 95% CI, 0.42-0.74).
In addition, the ORR was higher among women with measurable disease assigned ribociclib vs. placebo (40.9% vs. 28.7%).
Grade 3 adverse events included neutropenia, occurring in 46.6% of patients in the ribociclib arm vs. none in the placebo arm, and leukopenia, occurring in 13.5% of patients in the ribociclib arm vs. none in the placebo arm. – by Jennifer Southall
References:
Slamon DJ, et al. Abstract 1000. Presented at: ASCO Annual Meeting; June 1-5, 2018; Chicago.
Slamon DJ, et al. J Clin Oncol. 2018;doi:10.1200/JCO.2018.78.9909.
Disclosures: Slamon reports a leadership role with BioMarin; stock ownership in Amgen, Pfizer and Seattle Genetics; honoraria from Eli Lily, Novartis and Pfizer; consultant/advisory roles with Eli Lily and Novartis; research funding from Novartis and Pfizer; and payment for travel/accommodations/expenses from Biomarin, Eli Lily, Novartis and Pfizer. Please see the abstract for all other author’s relevant financial disclosures.