MabThera is a biological anti rheumatic agent. The mechanism of action is different from that of TNF-alpha-inhibitors that dominates the market. MabThera inhibits the B lymphocytes. Mabthera is given as two infusions separated by a 2 weeks time interval.
The registered indication is: “In combination with methotrexate for the treatment of adult patients with severe active rheumatoid arthritis (RA), who have had an inadequate response or intolerance to other disease modifying anti-rheumatic drugs (DMARD), including one or more tumour necrosis factor (TNF) inhibitor.”
The antirheumatic effect of MabThera is moderate in this patient population with very severe RA. If you treat RA-patients according to the registered indication, you must treat 3 patients to have one patient with a minimal improvement compared to placebo (ACR 20), and you have to treat about 9 patients to have one patient experiencing a marked improvement (ACR 70). When you treat patients with severe active RA (average DAS28 6,9), one patient out of 7 will achieve low disease activity (DAS < 3,2), and 1 out of 11 will achieve remission (DAS < 2,6).
Unfortunately no randomized studies exists that compare MabThera with TNF-alpha-inhibitors or abatacept in patients with active (RA) who have had an inadequate response to one or more TNF- alpha-inhibitors. Like other biological anti-rheumatica, Mabthera should be combined with methotrexate.
Acute infusion reactions, which in some cases can be serious, are seen in approximately 10 % of the patients in spite of premedication with corticosteroids. The frequency of infection is increased. Serious infections occur in about 1 per 75 treated patients during ½ a year.
One year of treatment with MabThera costs approximately 117.000 Dkr. per year with a new treatment cycle every 6 month. It is about the same price level as Remicade and cheaper than Enbrel and Humira. Mabthera is more than 100 times more expensive than oral methotrexate.