by Paul Cottu, Alistair Ring, Hikmat Abdel-Razeq, Paolo
Marchetti, Fatima Cardoso, Javier Salvador Bofill, Miguel Martín, Lakshmi
Menon-Singh, Jiwen Wu, Michelino De Laurentiis
The Breast: Published:January 31, 2022
Background
The phase IIIb CompLEEment-1 study evaluated ribociclib plus
letrozole in patients with hormone receptor–positive (HR+), human epidermal
growth factor receptor 2–negative (HER2–) advanced breast cancer (ABC).
Outcomes were investigated in the following subgroups: central nervous system
(CNS) metastases, prior chemotherapy for advanced disease, Eastern Cooperative
Oncology Group (ECOG) performance status (PS) 2, and visceral metastases plus
prior chemotherapy for advanced disease or ECOG PS 2.
Patients and methods
Patients with HR+, HER2– ABC without prior hormonal
treatment for advanced disease received oral ribociclib (600 mg once
daily, 3 weeks on/1 week off) plus letrozole (2.5 mg once daily,
continuous). Primary endpoint was safety/tolerability, assessed via occurrence
of adverse events (AEs); key secondary endpoints included time to progression
(TTP), overall response rate, and clinical benefit rate.
Results
51 patients had CNS metastases, 194 received prior
chemotherapy for advanced disease, 112 had ECOG PS 2, 146 had visceral
metastases plus prior chemotherapy, and 77 had visceral metastases plus ECOG PS
2. Safety results were consistent with those in the overall CompLEEment-1
population; no new safety concerns were identified. The AE profile was manageable
with low rates of discontinuations due to AEs. TTP in patients with CNS
metastases was consistent with the overall study population and shorter for
other patient subgroups. Each patient subgroup achieved meaningful clinical
benefit from treatment, consistent with the overall population.
Conclusion
These findings confirm the clinical benefit of ribociclib
plus endocrine therapy in high-risk patient subgroups of clinical interest
commonly underrepresented in clinical trials.
