OS benefit was limited to patients with endocrine sensitivity, defined as either a documented clinical benefit (CR, PR, or SD for ≥24 weeks) from at least one previous endocrine therapy regimen in the context of metastatic disease or the receipt of at least 24 months of adjuvant endocrine therapy before recurrence.

Endocrine sensitivity in adjuvant setting seems straight forward.  If diagnosed with primary metastatic disease, will you give a trial of endocrine therapy alone to demonstrate sensitivity then add CDK 4/6 thereafter or continue upfront CDK 4/6 inhibitor as has been the new standard of care?