Im SA, Mukai H, Park IH, et al. - Among 95 Asian postmenopausal women with estrogen receptor–positive/human epidermal growth factor receptor 2–negative advanced breast cancer who participated in PALOMA-2, researchers investigated the benefit of treatment with palbociclib plus letrozole, given that this combination significantly improved progression-free survival (PFS) in PALOMA-2 when administered as initial therapy for estrogen receptor–positive/human epidermal growth factor receptor 2–negative advanced breast cancer in postmenopausal women. A 2:1 random allocation of patients to palbociclib plus letrozole or placebo plus letrozole was done. Investigator-assessed PFS was considered the primary endpoint. Treatment with palbociclib plus letrozole vs placebo plus letrozole resulted in significantly longer median PFS in Asian patients (25.7 months vs 13.9 months, respectively). Consistent with the overall study population, a significant improvement was evident in PFS in Asians as a result of adding palbociclib to letrozole. Among Asians vs non-Asians, the frequency of hematologic toxicities was more, but these were manageable with early dose changes while maintaining quality of life.