A phase IV prospective study of efficacy and safety of ribociclib and letrozole as first-line therapy in older women (≥70 years) with hormone receptor-positive HER2-negative advanced breast cancer: The RibOB study

The RibOB study was an open-label, single-arm phase IV prospective trial evaluating first-line ribociclib with letrozole in 70 patients with HR+ HER2- advanced breast cancer who were aged 70 or older. The combination showed antitumor efficacy and was relatively well tolerated in this population, regardless of patient frailty.