MONDAY, Oct. 10, 2016 (HealthDay News) — Ribociclib plus letrozole is associated with significantly longer progression-free survival for patients receiving initial systemic treatment for hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer, according to a study published online Oct. 8 in the New England Journal of Medicine. The research was published to coincide with the annual European Society of Medical Oncology Congress, held from Oct. 7 to 11 in Copenhagen, Denmark.
Gabriel N. Hortobagyi, M.D., from the University of Texas MD Anderson Cancer Center in Houston, and colleagues conducted a randomized phase 3 trial to examine the efficacy and safety of ribociclib combined with letrozole for first-line treatment. Participants included 668 postmenopausal women with HR-positive, HER2-negative recurrent or metastatic breast cancer. Patients were randomized to receive either ribociclib plus letrozole or placebo plus letrozole. After 243 patients had disease progression or died, a planned interim analysis was performed.
The researchers found that the duration of progression-free survival was significantly longer in the ribociclib versus the placebo group (hazard ratio, 0.56). The median follow-up duration was 15.3 months. The progression-free survival rate was 63.0 and 42.2 percent in the ribociclib and placebo groups, respectively, after 18 months. The overall response rate was 52.7 and 37.1 percent, respectively, for patients with measurable disease at baseline (P < 0.001).
“The duration of progression-free survival was significantly longer among those receiving ribociclib plus letrozole than among those receiving placebo plus letrozole, with a higher rate of myelosuppression in the ribociclib group,” the authors write.
The study was funded by Novartis, the manufacturer of ribociclib and letrozole.
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