RT Journal Article T1 Safety and efficacy of ribociclib plus letrozole in patients with HR+, HER2- advanced breast cancer: Results from the Spanish sub-population of the phase 3b CompLEEment-1 trial. A1 Salvador Bofill, Javier A1 Moreno Anton, Fernando A1 Rodriguez Sanchez, Cesar Augusto A1 Galve Calvo, Elena A1 Hernando Melia, Cristina A1 Ciruelos Gil, Eva Maria A1 Vidal, Maria A1 Jiménez-Rodriguez, Begoña A1 De la Cruz Merino, Luis A1 Martínez Jañez, Noelia A1 Villanueva Vazquez, Rafael A1 de Toro Salas, Ruben A1 Anton Torres, Antonio A1 Alvarez Lopez, Isabel Manuela A1 Gavila Gregori, Joaquin A1 Quiroga Garcia, Vanesa A1 Vicente Rubio, Elena A1 De la Haba-Rodriguez, Juan A1 Gonzalez-Santiago, Santiago A1 Diaz Fernandez, Nieves A1 Barnadas Molins, Agusti A1 Cantos Sanchez de Ibargüen, Blanca A1 Delgado Mingorance, Juan Ignacio A1 Bellet Ezquerra, Meritxell A1 de Casa, Sonia A1 Gimeno, Asuncion A1 Martin, Miguel K1 Advanced breast cancer K1 CDK4/6 inhibitor K1 Postmenopausal K1 Premenopausal K1 Ribociclib K1 Área de Gestión Sanitaria de Jerez, Costa Noroeste y Sierra de Cádiz AB Breast cancer is the most common malignancy and the second leading cause of cancer-related mortality in Spanish women. Ribociclib in combination with endocrine therapy (ET) has shown superiority in prolonging survival in patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC) vs. ET alone. CompLEEment-1 is a single-arm, open-label phase 3b trial evaluating ribociclib plus letrozole in a broad population of patients with HR+, HER2- ABC. The primary endpoints were safety and tolerability. Here we report data for Spanish patients enrolled in CompLEEment-1. A total of 526 patients were evaluated (median follow-up: 26.97 months). Baseline characteristics showed a diverse population with a median age of 54 years. At study entry, 56.5% of patients had visceral metastases and 8.7% had received prior chemotherapy for advanced disease. Rates of all-grade and Grade ≥3 adverse events (AEs) were 99.0% and 76.2%, respectively; 21.3% of patients experienced a serious AE, and 15.8% of AEs led to treatment discontinuation. AEs of special interest of neutropenia, increased alanine aminotransferase, increased aspartate aminotransferase and QTcF prolongation occurred in 77.8%, 14.8%, 11.4% and 4.0% of patients, respectively. Patients aged >70 years experienced increased rates of all-grade and Grade ≥3 neutropenia and anemia. Efficacy results were consistent with the global study. Results from Spanish patients enrolled in CompLEEment-1 are consistent with global data showing efficacy and a manageable safety profile for ribociclib plus letrozole treatment in patients with HR+, HER2- ABC, including populations of interest. YR 2022 FD 2022-09-24 LK http://hdl.handle.net/10668/22065 UL http://hdl.handle.net/10668/22065 LA en NO Salvador Bofill J, Moreno Anton F, Rodriguez Sanchez CA, Galve Calvo E, Hernando Melia C, Ciruelos Gil EM, et al. Safety and efficacy of ribociclib plus letrozole in patients with HR+, HER2- advanced breast cancer: Results from the Spanish sub-population of the phase 3b CompLEEment-1 trial. Breast. 2022 Dec;66:77-84 DS RISalud RD Apr 4, 2025