Treatment and sampling schedule. (A) Treatment discontinuations. (B) The number of patients discontinuing at certain time points is shown in the bar graphs. Patients who discontinued treatment according to the protocol due to achievement of undetectable MRD and a (clinical) CR are shown in dark blue; patients who completed a maximum of 8 cycles of maintenance are shown in blue. Patients who stopped treatment early because of toxicity are depicted in red and disease progressions are shown in yellow. Other reasons (gray) include “physician’s decision” (n = 1) and “allogeneic stem cell transplantation” (n = 1). Every x on the sampling schedule represents an FCM and ctDNA sample. Benda, bendamustine; C1, cycle 1; C2, cycle 2; C3, cycle 3; C4, cycle 4; C5, cycle 5; C6, cycle 6; DB, debulking cycle 1; DB2, debulking cycle 2; IR, initial response assessment; M1, maintenance staging 1; M2, maintenance staging 2; Mx, maintenance stagings 3 to 8; obi, obinutuzumab; PD, clinical disease progression; RE, final restaging.