I was recently surprised to find out that there are a TON of approved therapeutic monoclonal antibodies. Monoclonal antibodies are simply clonal antibodies, they all are exactly the same and thus bind the exact same antigen. In the case of therapeutic monoclonal antibodies these are drug targets. And I thought they were just good for western blots and coimmunoprecipitation!
In my defence I was aware of two approved monoclonal antibodies, herceptin and avastin. Both are for cancer treatment, so it makes sense that I would know them. Herceptin targets defective HER2 mitogen receptors that are stuck in the 'on' position, and herceptin is able to stop this activity by binding to these cell surface receptors. Avastin binds to VEGF, thereby preventing VEGF from stimulating new blood vessels to form in growing tumours thus cutting them off from oxygen and nutrients.
This relatively new class of drugs are effective and the market is growing fast, unfortunately they are also extremely expensive. Since they are such big business there are lots of new monoclonal antibody therapies out there. According to wikipedia:
"The current “big 5” therapeutic antibodies on the market: Avastin, Herceptin (both oncology), Humira, Remicade"..." and Rituxan (oncology and AIID) accounted for 80% of revenues in 2006"
But that must mean there are some interesting alternative monoclonals out there, here are a few that are perhaps a bit more unique:
Rituxan is useful for both autoimmune disorders and non-Hodgkin lymphoma because it targets CD20 on Bcells which are producing autoantibodies, in the case of autoimmunity, or are proliferating unchecked in the case of non-Hodgkins.
Palivizumab is a monoclonal that prevensts Respiratory Syncytial Virus infection.
Abciximab blocks platelet activation an thus blood clotting.
Efalizumab binds CD11a and is thus immunosuppressive and used to treat psoriasis, but due to side-effects of this immunosuppression it is being withdrawn from the market.
HCV-AbXTL68 is used in HCV positive patients undergoing liver transplant to prevent infection of the new liver.
Most of the monoclonal antibodies are for cancer or for autoimmune disorders.
Check out the diagram from wikipedia for a quick look at the strategies used to treat cancer with monoclonal antibodies.