Subjects who have previously received IPI-145 in study IPI-145-07 will receive a starting dose of 300 mg ofatumumab on Day 1 followed by seven weekly doses of 2000 mg. Thereafter, subjects will receive 2000 mg ofatumumab once every month for four months unless disease progression or unacceptable toxicity occurs. Administration of ofatumumab will not exceed the 12 doses (within 7 cycles).