RT Journal Article T1 Randomized phase II study of fulvestrant plus palbociclib or placebo in endocrine-sensitive, hormone receptor-positive/HER2-advanced breast cancer: GEICAM/2014-12 (FLIPPER). A1 Albanell, J. A1 Martínez-García, M. A1 Ramos-Boyero, Manuel A1 O'Connor, Miriam A1 De-la-Cruz-Merino, Luis A1 Santaballa-Bertrán, Ana A1 Martínez-Jáñez, Noelia A1 Moreno-Antón, Fernando A1 Fernández, Isaura A1 Alarcón, Jesús Damián A1 Virizuela-Echaburu, Javier Antonio A1 De-la-Haba-Rodríguez, Juan Rafael A1 Sánchez- Rovira, P A1 González-Cortijo, Lucía A1 Margelí, Mireia A1 Sánchez-Muñoz, Alfonso A1 Antón, A. A1 Casas, María Isabel A1 Bezares, Susana A1 Rojo, Federico K1 Mamas - Cáncer - Tratamiento AB Background: The potential benefit of adding palbociclib to fulvestrant as first-line treatment in hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative endocrine-sensitive advanced breast cancer (ABC) patients remains uncharacterized.Patients and methods: In this randomized (1:1), double-blind, phase II study, postmenopausal women with HR-positive, HER2-negative ABC with de novo metastatic disease or those who relapsed after >12 months of adjuvant endocrine therapy received palbociclib/fulvestrant or placebo/fulvestrant. Stratification was based on recurrent versus de novo metastatic disease and visceral involvement. The primary objective was one-year progression-free survival (PFS-1y) rate. The sample size was 190 patients. The two-sided alpha of 0.2, 80% of power to detect a difference between the arms, assuming PFS rates of 0.695 and 0.545 for palbociclib/fulvestrant and placebo/fulvestrant, respectively.Results: In total, 189 patients were randomized to palbociclib/fulvestrant ([n = 94] or placebo/fulvestrant [n = 95]). 45.5% and 60.3% of patients had de novo metastatic disease and visceral involvement, respectively. PFS-1y rates were 83.5% and 71.9% in the palbociclib/fulvestrant and placebo/fulvestrant arms, (HR 0.55, 80% CI 0.36-0.83, P = 0.064). The median PFS were 31.8 and 22.0 months for the palbociclib/fulvestrant and placebo/fulvestrant arms (aHR 0.48, 80% CI 0.37-0.64, P = 0.001). The most frequent grade 3-4 adverse events were neutropenia (68.1% vs. 0%), leucopenia (26.6% vs. 0%), anemia (3.2% vs. 0%), and lymphopenia (14.9% vs. 2.1%) for the palbociclib/fulvestrant and placebo/fulvestrant, respectively. The most frequent non-hematologic grade 3-4 adverse event was fatigue (4.3% vs. 0%).Conclusions: Palbociclib/fulvestrant demonstrated better PFS-1y rates and median PFS than placebo/fulvestrant in HR-positive/HER2-negative endocrine-sensitive ABC patients. PB Elsevier YR 2022 FD 2022 LK https://hdl.handle.net/10630/31278 UL https://hdl.handle.net/10630/31278 LA eng NO Albanell J, Martínez MT, Ramos M, O'Connor M, de la Cruz-Merino L, Santaballa A, Martínez-Jañez N, Moreno F, Fernández I, Alarcón J, Virizuela JA, de la Haba-Rodríguez J, Sánchez-Rovira P, González-Cortijo L, Margelí M, Sánchez-Muñoz A, Antón A, Casas M, Bezares S, Rojo F. Randomized phase II study of fulvestrant plus palbociclib or placebo in endocrine-sensitive, hormone receptor-positive/HER2-advanced breast cancer: GEICAM/2014-12 (FLIPPER). Eur J Cancer. 2022 Jan;161:26-37. doi: 10.1016/j.ejca.2021.11.010. Epub 2021 Dec 11. PMID: 34902765. NO Este artículo ha sido publicado en la revista European Journal of Cancer. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). DS RIUMA. Repositorio Institucional de la Universidad de Málaga RD 22 ene 2026