Ribociclib + letrozole in patients with bone-only disease had a safety profile consistent with that observed in the full population (Burris HA et al. First-line ribociclib + letrozole in patients with HR+/HER2– advanced breast cancer presenting with visceral metastases or bone-only disease: a subgroup analysis of the MONALEESA-2 trial. This evidence concerns the gene HR and breast cancer.