Rituxan (Rituximab) is a genetically-engineered antibody which blocks the action of a protein called CD20 - it has regulatory approval for treatment of Rheumatoid Arthritis in many countries.

Another class of genetically-engineered antibodies that you could consider are those which block the action of a protein called TNF. TNF contributes to the inflammatory aspect of auto-immune diseases like Rheumatoid Arthritis.

Examples of these therapeutic antibodies include Infliximab, Golimumab and Adalimumab (there are others) - they are an option which is worth discussing with your clinical care team.