Rituximab is a monoclonal antibody directed against CD20, a cell surface receptor found on B-cells and has proved to be a general immunosuppressant. It was a blockbuster medication. May be used in combination with other chemotherapeutic agents, e.g. CHOP, but may be used as monotherapy in treatment of non-Hodgkin's lymphoma in patients who are not fit enough for chemotherapy or have advanced disease. It is widely used as a third line agent in various auto-immune disorders and with the coming to market of biosimilars is predicted to also evolve into first line use as in some indications the evidence for clinical benefit already exists but such use has been constrained by cost benefit issues. As of 2017 there are three licensed products in Europe. Much of use has evolved to be unlicensed as there has proved to be little incentive and some difficulties in undertaking studies that meet licensing requirements, in disease presentations refractory to other treatment.
- Relapsed/refractory follicular lymphoma responding to induction therapy with chemotherapy
- Stage III-IV follicular lymphoma in combination with chemotherapy
- CD20+ive diffuse large B cell non-Hodgkin's lymphoma in combination with CHOP chemotherapy
- Castleman's disease
- Rheumatoid arthritis
- Granulomatosis with polyangiitis (Wegener's granulomatosis)
May be used as an immunosuppressant in:
- Transplant rejection
- Certain nephropathies
- Auto-immune disorders such as
Cautions and Interactions
A monoclonal antibody directed against the CD20 antigen expressed by B-lymphocytes. Courses of therapy deplete for some time such activated B-lymphocytes and in autoimmune disease they are typically removed from the circulation for between 6 to 12 months.
It was co-developed by Biogen Idec and Genentech. It received marketing approval from the US Food and Drug Administration for non-Hodgkin's lymphoma in 1997 and EMEA approval in June 1998. Genentec was taken over by Roche and in due course the product that had been developed as an orphan drug was generating over US$7 billion annual sales, being one of the most lucrative blockbusters of the early 21st century. Product sales growth rate globally was about 5% when biosimilar competition started to enter patent protected markets from about 2015 and quickly took on close to 50% of the market.