Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune condition viewed as a severe destructive disease. The treatment strategies include anti-CD20 monoclonal antibody (mAb)-targeting B cells. Ofatumumab specifically targets a membrane-proximal epitope on the CD20 molecule distinct from other anti-CD20 antibodies including rituximab and ocrelizumab, and bind the epitope located on the large loop of CD20. This explains a more durable B-cell depletion and a different pharmacodynamic. We review the pharmacodynamic of B-cell depletion and analyze the results in RA and other B-cell-mediated autoimmune diseases. The randomized trial in RA showed clinical efficacy comparable to rituximab at week 24. However, structural impact has not been demonstrated. Studies including RA patients refractory to rituximab would be useful to define the optimal strategy of ofatumumab therapy.