Biologics are the newest drugs designed to treat rheumatoid arthritis (RA). They are either injected under the skin or delivered directly into a vein. They work by neutralizing one of the immune system's signals that lead to inflammation and joint damage. (Rituximab (Rituxan) and tocilizumab (Actemra) are biologics, but do not block TNF. Rituxan targets B cells and Actemra affects IL-6.) When used with methotrexate, these medicines help most people with rheumatoid arthritis with fewer side effects. One side effect is the risk for potentially severe infections. These medicines can also, although rarely, adversely affect your liver or blood counts.