Dear OncoLink "Ask the Experts,"
I have a question regarding Rituxan. I am having difficulty finding information on this therapy. My father has non-Hodgkins lymphoma which was diagnosed in April of 1998. C.H.O.P. chemotherapy regimen was unsuccessful. He has now developed a tumor behind the pancreas with tremendous amount of ascites (fluid in the abdomen). The doctor wants to give Rituxan instead of Interferon. Please advise.
John Han-Chih Chang, MD and Kenneth Blank, MD, Editorial Assistants for OncoLink, respond:
Rituxan is a relatively new weapon in the arsenal against non-Hodgkin's lymphoma (NHL). Over 90% of B-cell type NHL express the CD-20 antigen. This has made it an appealing target for therapy in this malignancy. It is a type of immunotherapy similar to interferon. The difference is that interferon attempts to "gear up" the overall immune system to promote tumor surveillance, and thus tumor destruction by the immune system. Rituxan is a monoclonal antibody for the CD-20 antigen to which it binds and causes an host effector response ? leading the body's immune system to destroy the "marked" cells.
The only way for this to be effective is if the cells that are being targeted have CD-20 expression. Your father's oncologist or cancer physician who is intent on treating your father with this agent should know if the NHL that your father has expresses CD-20 and is of B-cell type. It has not been demonstrated to be a cure for relapsed or chemo-unresponsive disease. It has a 40 ? 60% response rate in recent studies with a median duration of response equal to 6 ? 13 months. The toxicities from treatment have been mild and include fevers, chills, nausea, rash and urticaria. Thus, Rituxan is a very tolerable treatment, which may have some benefit. The reality is that it remains a novel treatment, which has not produced a cure at this time.
Along the same lines, a new type of therapy that utilizes antibodies has been developed by the University of Michigan. The antibody is tagged with a radioactive isotope and given to the patient. This uses the principle described above and also the fact that NHL are very sensitive to radiation therapy. This has been deemed radioimmunotherapy and presented some promising initial results.
Please discuss these issues with your father's physicians.