Palbociclib Plus Fulvestrant Increases OS in HR +, HER2-Negative Breast Cancer

Hormone receptor-positive (HR +) bad cancer is the most common subtype for the disease. Whereas prolonged-free survival between patients with previously untreated estrogen receptor-positive (ER +), and cyclin-dependent kinases 4 and 6 (CDK4 / 6) HER2-negative advanced bad cancer, long-term data regarding the effect of palbociclib on overall survival (OS) and the efficacy of subsequent therapy has been limited.

The PALOMA-3 trial, a prospective, international, randomized, double-blind, placebo-controlled phase 3 trial compared with palbociclib plus fulvestrant with placebo plus fulvestrant in women with HR +, HER2bad cancer who had disease progression after endocrine therapy.

The study enrolled 521 patients and randomized them in a 2: 1 ratio to receive either palbociclib plus fulvestrant (n = 347) or placebo plus fulvestrant (n = 174). Researchers defined OS as the time from randomization to death from any cause.

Data regarding OS has been badyzed at a median follow up of 44.8 months. A total of 201 deaths occurred in the palbociclib plus fulvestrant group, and 109 deaths in the placebo plus fulvestrant group. The median OS was 34.9 months (95% CI, 28.8 to 40.0) in the palbociclib plus fulvestrant group and 28.0 months (95% CI, 23.6 to 34.6) in the placebo plus fulvestrant group. The estimated rate of OS at 3 years in the Kaplan-Meir badysis was 50% (95% CI, 44.0 to 55.0) in the palbociclib plus fulvestrant group and 41% (95% CI, 33.0 to 48.0) in the placebo plus fulvestrant group . Additionally, the safety profile of palbociclib plus fulvestrant remained consistent with the primary badysis.

The results of the badysis did not meet the prespecified threshold for statistical significance, but the result of palbociclib to fulvestrant resulted in "an absolute prolongation of overall survival of 6.9 months among patients with HR +, HER2-negative advanced bad cancer. "The study authors noted that in the subgroup of patients with previous endocrine therapy, OS was 10 months longer with palbociclib more fulvestrant than placebo.

Reference

Turner N, Slamon D, Ro J, et al. Overall survival with palbociclib and fulvestrant in advanced bad cancer [published online October 20, 2018]. N Engl J Med. doi: 10.1056 / NEJMoa1810527

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