PB and BM MRD assessments. On the x-axis, the MRD assessment in the BM is given, on the y-axis the MRD value in the PB is given; both are expressed as percentage of leukocytes. (A) Patients treated with venetoclax only. (B) Patients treated with venetoclax monotherapy followed by venetoclax combined with ibrutinib until uMRD4, progressive disease, unacceptable toxicity, or Cycle 24 Day 28, whichever occurs first. The pie chart in each graph illustrates the percentage of PB uMRD4 with concordant (in green) or discordant (in yellow and red) BM MRD levels.