Aiming at tumor molecules:
Conventional treatments for cancer like radiotherapy and chemotherapy can be very effective, but they usually end up damaging some normal cells as well as they act on all cells. If we could target the treatment in such a way that only the tumor cells got attacked, we could reduce many of the side effects of treatment. One way to achieve this is to target unique molecules that are present on the surface of tumor cells.
What are Monoclonal Antibodies (MAb)?:
The immune system in our body can identify things that dont belong to our own body like infections. It locates unique molecules on the surface of these foreign cells, called antigens. It then produces special proteins called antibodies aimed specifically against those cells so that they can be killed. Antibodies can also be produced against tumor cells. Using special techniques, a single anti-tumor antibody is copied into millions. These are then used to specifically target tumor cells.
Rituximab shows the way:
The first monoclonal antibody to enjoy wide success is called Rituximab (Rituxan). Rituximab acts against CD20, a special molecule on the surface of B-cell Non-Hodgkin Lymphomas. When it attaches to the molecule, lymphoma cells begin to die. This monoclonal antibody is now a part of standard treatment of both low grade and intermediate grade B-cell Non-Hodgkin Lymphomas. It has been shown to save lives.
Adding some punch to the MAb:
Scientists have tried packing a punch with the MAb. By attaching a radiation emitting substance to the monoclonal antibody, they have aimed to kill lymphoma cells even better. Two molecules Ibritumomab (Zevalin) and Tositumomab (Bexxar) have been tried on patients with low grade B-cell Non-Hodgkin Lymphoma. Both have shown great success.
Where are we headed?:
While Rituximab is in wide use as a standard of care, Ibritumomab and Tositumomab are now being tried out in large clinical trials. If they are found to be successful, they can also become a routine part of treatment and improve outcomes. Once approved, many more individuals will be able to receive these molecules as treatment. Other molecules are also being investigated. We may be on the verge of a molecular revolution in lymphoma treatment.