Toxicity and costs of cancer treatment reduced by deferring CDK4/6 inhibitor use

The SONIA study shows that early use of inhibitors that target both CDK4 and CDK6 (hereafter, CDK4/6) in metastatic breast cancer prolongs time on treatment but does not improve patient outcomes. Postponing innovative treatments to a later stage of the disease could thus safely reduce the time on treatment, the number of adverse effects for people with breast cancer and the burden on health-care resources. No difference in survival outcomes between use of CDK4/6 inhibitors as first- or second-line treatment in metastatic breast cancer.