A phase 3 multicenter, randomised, prospective, open-label trial of fixed-duration (12 cycles) venetoclax/ obinutuzumab vs. fixed-duration (15 cycles) venetoclax/ pirtobrutinib vs. MRD-guided venetoclax/ pirtobrutinib in patients with previously untreated chronic lymphocytic leukaemia (CLL)/ small lymphocytic lymphoma (SLL) aiming to establish measurement of individual residual disease for adjustment of treatment duration to improve outcomes