The SONIA trial shows the power and challenges of academic research

The thought-provoking SONIA trial showed that patients with hormone receptor-positive, HER2-negative advanced-stage breast cancer receiving deferred (second-line) versus first-line cyclin dependent-kinase (CDK) 4/6 inhibitors have noninferior progression-free survival after second-line treatment; such an approach also results in substantial cost savings. Herein, we discuss some important limitations of this trial and argue that, owing to their effect on overall survival, CDK4/6 inhibitors should remain the standard-of-care first-line therapy.