Mindful of the coming approval of abemaciclib, how would you decide between a CDK 4/6 inhibitor in either the first or second-line setting in HR-positive, HER2-negative postmenopausal metastatic breast CA?

Side effect profile is generally a good starting point since there is no head to head comparison (not will there likely be).

Abemaciclib does have a higher incidence of diarrhea but also a lower incidence of neutropenia. It also has the advantage of daily dosing which can be less confusing for pati...