Primary outcome analysis of the phase 3 SONIA trial (BOOG 2017–03) on selecting the optimal position of cyclin-dependent kinases 4 and 6 (CDK4/6) inhibitors for patients with hormone receptor-positive (HR+), HER2-negative (HER2− advanced breast cancer (ABC) - Sonke, GS; Van Ommen-Nijhof, A; Wortelboer, N (J Clin Oncol, 2023)