Treatment schema by group. Oral ibrutinib 420 mg was given once daily until disease progression or unacceptable toxicity. Intravenous ofatumumab was given as 8 weekly infusions followed by 4 monthly infusions for a total of 12 doses (dose 1, 300 mg; doses 2-12, 2000 mg). Group 1, ibrutinib monotherapy during cycle 1 and then ofatumumab added starting cycle 2; group 2, ofatumumab and ibrutinib starting on days 1 and 2 of cycle 1, respectively; group 3, ofatumumab monotherapy for the first 2 cycles and then ibrutinib added starting at cycle 3.