Rituximab is now an officially approved treatment for rheumatoid arthritis, vaculitis, Wegner's syndrome as well as lymphoma. It has much anecdotal evidence for being effective in treating Myasthenia Gravis, Lupus, MS and several other serious autoimmune illnesses. It is called "B cell ablation therapy" because it mostly wipes out the B cells in the human body. B cells produce inflammatory cytokines, such as IL-6 or TNF-a which seem to be highly implicated in the genesis of these illnesses. Under rituximab therapy, doctors have noted a commensurate decline in these inflammatory hormones as the B cells are gradually killed off. Usually the B cells have to be wiped out for a couple of years to achieve complete remission (as is the case with RA). The therapeutic pathway of rituximab is completely transparent and logical. The dynamic is indisputable.
Rituximab has now been prescribed to well over 100,000 recorded patients. There is a solid baseline for negative outcomes and side effects. The most lethal side effect is PML, a reactivation of a virus in the lining of the brain. The incidence in the use of Rituximab is approximately 1 death per 42,000 treatments. Biogen, creators of rituximab back in the late 90s, is now is pushing another monoclonal antibody Ocrelizumab for MS. Ocrelizumab has a PML incidence of 1:10,000, and it is less effective in controlling MS symptoms. The logical thing would be to continue testing rituximab in a host of autoimmune diseases, but Biogen has nothing to gain because it is off patent. The drug can be prescribed off label. It is cheapest when infused at a rheumatologist or oncologist's office, for somewhere between $6000 and $10000 per dose. The effectiveness of a dose seems to be between 6 and 8 months. Hospitals, as usual, charge astronomical amounts, usually between $15000 on up per dose.
The histories of long-term rituximab users have been tracked for a number of years. The drug was first marketed in the late 90s. Researchers have been surprised to find that none of the suspected consequences of wiping out B cells, for years at a time, have come to pass. No notable increased cancers, few new infections. Rituximab is safe and effective when taken long term. The body is not left defenseless when this component is removed. This has lead some researchers to conclude that the immune system is redundant and adaptive enough to make up for the loss of the B cells. Even after annihilation of B cells by rituximab, the body's defenses some how regroup and continue on successfully defending the body against cancer and infection.The total number of cases studied, in one article, was 124,000 patients. So the evidence supporting its relative safety is well established.