1370 - Interim Results From CompLEEment-1 (A Phase 3b Study of Ribociclib and Letrozole as First-Line Therapy for Advanced Breast Cancer in an Expanded Population): Spanish cohort results

Background

In Spain luminal metastatic Breast Cancer accounts for more than 3000 deaths yearly. Ribociclib+letrozole has shown efficacy on prolonging progression free survival (PFS) vs placebo+letrozol in two phase 3 trials. However, data on efficacy and tolerability is lacking for a broader population. We present interim data from CompLEEment-1, an ongoing, open-label, phase 3b trial evaluating ribociclib+letrozole as first-line endocrine therapy in an expanded population of patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2–) advanced breast cancer (ABC).

Methods

Patients treated with ≤1 line of prior chemotherapy and no prior endocrine therapy for advanced disease received ribociclib 600 mg/day (3-weeks-on/1week-off) + letrozole (2.5 mg/day; plus monthly goserelin or leuprolide in men and premenopausal women). The primary objective was safety and tolerability. Here we report a sub-analysis of CompLEEment-1 for the Spanish population.

Results

526 patients were evaluated over a median follow-up of 10.3 months. Baseline characteristics indicated a diverse population with median age of 55.6 years (range 24-85); 0.8% of patients were male, 34.6% female pre-menopausal and 64.6% female post-menopausal. 71% had visceral metastasis, in 8 cases at the CNS. 55.9% had measurable disease at baseline. The rate of all-grade and grade ≥ 3 treatment-related adverse events (AEs) was 98.5% and 70.0%, respectively. Treatment-related serious AEs occurred in 12.2% of patients. All-grade and grade ≥ 3 AEs leading to ribociclib discontinuation occurred in 13.7% and 8.2% of patients, respectively. Rates of ≥ 3 AEs of special interest (AESI) were 59.5% for neutropenia, 6.8% for increased alanine aminotransferase, 4.8% for increased aspartate aminotransferase, and 0.6% for QTcF prolongation. Patient health-related quality of life was maintained versus baseline.

Conclusions

Initial results from the Spanish cohort in CompLEEment-1 are consistent with previous data showing efficacy and a manageable safety profile of ribociclib plus letrozole as a first-line treatment option in a diverse group of patients with HR+, HER2– ABC. Acknowledgement: Dr. J. Gavilá-Gregori, Dr. M.J. Martinez-Serrano and Dr. M. Perelló contributed equally to this study.

Clinical trial identification

NCT02941926.

Editorial acknowledgement

Legal entity responsible for the study

Novartis Pharmaceuticals Corporation.

Funding

Novartis Pharmaceuticals Corporation.

Disclosure

E.M. Ciruelos: Advisory / Consultancy, Speaker Bureau / Expert testimony, Speaker and ad.board honoraria: Novartis; Advisory / Consultancy, Speaker Bureau / Expert testimony, Speaker and ad.board honoraria: Lilly; Advisory / Consultancy, Speaker Bureau / Expert testimony, Speaker and ad.board honoraria: Roche; Advisory / Consultancy, Speaker Bureau / Expert testimony, Speaker and ad.board honoraria: Pfizer. R. Villanueva Vázquez: Advisory / Consultancy: Novartis; Advisory / Consultancy: Pfizer; Advisory / Consultancy: Roche. F. Moreno: Advisory / Consultancy, Travel / Accommodation / Expenses: Novartis; Advisory / Consultancy, Travel / Accommodation / Expenses: Pfizer; Advisory / Consultancy, Travel / Accommodation / Expenses: Roche; Advisory / Consultancy: AstraZeneca; Advisory / Consultancy: Eisai; Advisory / Consultancy: MSD. I. Álvarez: Research grant / Funding (institution): Novartis; Advisory / Consultancy, Research grant / Funding (institution), Travel / Accommodation / Expenses: Roche. S. González-Santiago: Research grant / Funding (institution): Novartis; Research grant / Funding (institution): Roche; Research grant / Funding (institution): Eisai; Research grant / Funding (institution): AstraZeneca. A. Barnadas: Advisory / Consultancy, Research grant / Funding (institution), Travel / Accommodation / Expenses: Roche; Advisory / Consultancy, Research grant / Funding (institution), Travel / Accommodation / Expenses: Novartis; Advisory / Consultancy, Research grant / Funding (institution), Travel / Accommodation / Expenses: Pfizer; Research grant / Funding (institution): Bristol-Myers Squibb; Advisory / Consultancy, Research grant / Funding (institution), Travel / Accommodation / Expenses: AstraZeneca; Research grant / Funding (institution): Lilly; Advisory / Consultancy, Travel / Accommodation / Expenses: Eisai; Advisory / Consultancy, Travel / Accommodation / Expenses: Genomic Health; Advisory / Consultancy, Travel / Accommodation / Expenses: Pierre Fabre. B. Cantos: Research grant / Funding (institution), Study enrollment: Fundación para la Investigación del Hospital Puerta de Hierro de Majadahonda; Advisory / Consultancy: Novartis; Advisory / Consultancy: Roche; Advisory / Consultancy: Celgene; Advisory / Consultancy: AstraZeneca. M. Bellet Ezquerra: Advisory / Consultancy: Novartis; Advisory / Consultancy: Pfizer; Advisory / Consultancy: Lilly. M. Martín: Advisory / Consultancy, Research grant / Funding (institution): Novartis; Advisory / Consultancy, Research grant / Funding (institution): Roche; Advisory / Consultancy: Lilly; Advisory / Consultancy: Pfizer; Advisory / Consultancy: Pharmamar; Advisory / Consultancy: Taiho Oncology; Advisory / Consultancy: Amgen; Advisory / Consultancy: AstraZeneca; Advisory / Consultancy, Research grant / Funding (institution): Puma. N. Martínez: Research grant / Funding (institution): Roche; Research grant / Funding (institution): Pfizer; Research grant / Funding (institution): Eisai; Research grant / Funding (institution): AstraZeneca. All other authors have declared no conflicts of interest.