When should paclitaxel (or other chemo) be discontinued in de novo metastatic triple negative breast cancer with high PDL1 in favor of continuing pembrolizumab alone with good treatment response?

The KEYNOTE-355 trial was designed so that investigators continued chemotherapy until "confirmed disease progression or unacceptable toxic effects had occurred or withdrawal of consent or physician’s decision" (Cortes et al., PMID 35857659). I think this is a good strategy. It's not a satisfying ans...