Friday, March 14, 2008
Treating Non-Hodgkin lymphoma
Until now, patients suffering of Non-Hodgkin lymphoma were treated with chemotherapy and radiation. In some of the cases the treatment was useful but in most patients treatment was very toxic and did not lead to a cure. The scientists are trying to find a better treatment that will not have such toxic effects on the organism.
Scientists have tested the "Monoclonal-antibody–based" therapy and the conclusions were promising. An antibody is a substance created by the human immune system to fight against foreign germs, viruses and bacterium. Each antibody is designed to recognize a specific target (antigen). When the antibody and the antigen get connected, the immune system is alerted and so it is ready to fight with the foreign substance.
Monoclonal antibodies are made in a laboratory and are all the same and are designed to fight only one type of foreign substance like tumors.
Until now scientists have tested antibodies created by a mouse model, a human model and chimeric (half mouse, half human) and they want to see which one is the most effective against cancer.
Most of the patients diagnosed with Non-Hodgkin lymphoma are affected by tumors made out of B-cell lymphocytes, and so, monoclonal antibodies are designed to fight these modified B-cells that create tumors.
During tests, a toxic substance designed to kill cancerous cells has been attached to the antibody in order to reach these cells. Also, radio-labeled antibodies were tested to see if they can improve the radiation therapy. The radio-labeled antibodies are nor suitable in the therapy of those who have bone marrow cancer because radiation could cause hematological toxicity.
Since tests begun the only monoclonal antibody approved to be used was Rituxan. The treatment is followed once a week, for a month and the drug is given intravenously. Rituxan does not give such unbearable side effects like radiation or chemotherapy does; its side effects are only chills, fever or shakes. The radio-labeled combination has been tested too and the anti-tumor effects are quite remarkable. The side effects seamed to be manageable.
Bexxar is another monoclonal antibody that is being tested but is not yet approved for Non-Hodgkin lymphoma. It has a radioactive iodine molecule attached to, and also binds to the surface of B-cells. Side effects are similar to those caused by Rituxan, but the patient is advised to take an oral iodine supplement in order to protect its thyroid from any damage caused by radioactive iodine. Bexxar has been tested on low-grade NHL and one third of the patients had a complete remission, and 70% responded well to the treatment.
It is possible for the patient to develop an immune response against the antibody because this is a foreign substance too, but such cases are rare and appear mostly in the patients that did not have chemotherapy and have a less affected immune system.
Oncolym is another monoclonal antibody that is being tested. Results recommend it for a more aggressive form of NHL.
Before replacing the standard treatment, monoclonal antibodies have to be tested more and secure doses must be established for preventing other damages to install in the human body.
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