Palbociclib plus letrozole versus placebo plus letrozole in Asian postmenopausal women with oestrogen receptor–positive/human epidermal growth factor receptor 2–negative advanced breast cancer: Primary results from PALOMA-4 Journal Articles uri icon

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  • BACKGROUND: The cyclin-dependent kinase 4/6 inhibitor palbociclib has demonstrated efficacy and a manageable safety profile in combination with endocrine therapy in women with oestrogen receptor-positive (ER+)/human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC) in international phase 3 trials. The phase 3 PALOMA-4 trial evaluated the efficacy and safety of palbociclib plus letrozole versus placebo plus letrozole in Asian women with ER+/HER2- ABC. METHODS: Postmenopausal women (n = 340) with no prior systemic treatment for advanced disease were randomised 1:1 to palbociclib (125 mg/d orally; 3 weeks on, 1 week off) plus letrozole (2.5 mg/d orally; continuously) or placebo plus letrozole. The primary end-point was investigator-assessed progression-free survival (PFS). Secondary end-points included tumour response and safety. RESULTS: Median (95% CI) PFS was 21.5 (16.6-24.9) months with palbociclib plus letrozole and 13.9 (13.7-16.6) months with placebo plus letrozole (hazard ratio, 0.68 [95% CI, 0.53-0.87]; P = 0.0012). Consistent with the established safety profile, the most common adverse events (AEs) with palbociclib plus letrozole were neutropenia, leukopenia, thrombocytopaenia, and anaemia. Grade 3/4 neutropenia was reported in 84.5% of patients in the palbociclib arm versus 1.2% in the placebo arm. One serious AE of febrile neutropenia in the palbociclib group was reported. CONCLUSIONS: Findings from PALOMA-4 support the efficacy and safety of first-line palbociclib plus letrozole in postmenopausal Asian women with ER+/HER2- ABC. No new safety concerns of palbociclib plus letrozole were identified. TRIAL REGISTRATION: Clinicaltrials. gov, NCT02297438.


  • Xu, Binghe
  • Hu, Xichun
  • Li, Wei
  • Sun, Tao
  • Shen, Kunwei
  • Wang, Shusen
  • Cheng, Ying
  • Zhang, Qingyuan
  • Cui, Shude
  • Tong, Zhongsheng
  • Geng, Cuizhi
  • Song, Erwei
  • Huang, Chiun-Sheng
  • Sriuranpong, Virote
  • Ngan, Roger KC
  • Chia, Yee H
  • Wang, Xinwei
  • Zhao, Huadong

publication date

  • November 2022