Effectiveness of ribociclib in metastatic breast cancer in one hospital in Bulgaria—results from real-world clinical practice

Real-world evidence (RWE) complements randomized clinical trial data by demonstrating treatment effectiveness in routine practice and unselected populations. Despite the broad use of ribociclib, real-world data remain limited, particularly in Eastern Europe. This retrospective single-center analysis evaluated outcomes in Bulgarian patients treated with ribociclib and compared them with national and international evidence. Of 156 patients, 71.8% received first-line therapy, and 80.2% had ECOG performance status 0. The clinical benefit rate was 86.9% overall and 90.9% in the first line. Median progression-free survival was 17.7 months overall and 19.9 months in the first line. Outcomes were comparable to pivotal phase III trials and national real-world data. In the Bulgarian setting, early use of ribociclib in patients with favorable performance status may achieve results similar to or better than those observed in broader national cohorts, highlighting the importance of optimal patient selection and management.