In light of RIGHT Choice trial data, when will you opt for a CDK 4/6 inhibitor plus AI instead of chemotherapy in patients with metastatic HR-positive HER2-negative breast cancer with visceral crisis?

I think it is very reassuring to see that ribociclib + ET led to similar (or better) overall response rates than combination chemotherapy in the RIGHT choice trial presented at SABCS 2022. However, it is incredibly important to keep in mind that the definition of "impending visceral compromise" or "markedly symptomatic non-visceral disease" were left to the physician's judgement, and not objectively pre-specified in the inclusion criteria. I think that this is problematic, particularly when the ...

I will certainly consider it a lot more than prior to these results. I would still favor doublet chemotherapy in cases where rapid response is necessary to avoid impending life-threatening crises since endocrine therapy has a delayed onset of action.

Responses to CDK4/6 inhibitors are fairly rapid. I have been using abemaciclib with an AI in a neoadjuvant setting and have seen significant shrinkage of tumors in 2-3 weeks. Similarly, in metastatic disease, responses are fairly rapid. So in the metastatic setting, I would use a CDK4/6 inhibitor unless the patient was incapable of taking tablets or has significant pulmonary compromise.