Mouse guts are good for you

Lung cancer patients who developed a rash after treatment with the drug cetuximab (Erbitux) lived longer and had better progression-free survival rates than patients who did not develop a rash.

The study, led by Dr. Ulrich Gatzemeier from Hospital Grosshansdorf in Germany, looked at patients who received standard chemotherapy combined with cetuximab as well as patients who received standard chemo on its own.  70% of the cetuximab patients developed a rash and did better than the patients--cetuximab or not--that did not develop a rash.

Seems like a controlled study to look at the effects of continuing or stopping cetuximab in patients with the rash would be a good next step.

I'm certainly no expert, but the "-mab" ending of "cetuximab" means that this is a Monocolonal Anti Body, which generally targets specific antigens or epitopes expressed on cancer cells.  It's a "chimeric" antibody, meaning that it's derived from a combination of mouse and human DNA (-xi- before -mab means that there's a combination of human and foreign DNA...-o- would be mouse alone; -uz- would be humanised).

Cells expressing this antigen are then singled out to be killed.  But people who receive other monoclonal antibodies (monoclonal meaning they target one particular antigen) as part of cancer treatments often have an allergic reaction the first time their immune system has to deal with mouse proteins.  Indeed, their doctors and nurses say that a reaction is a *good* thing (though the poor feverish patient may disagree), as it means that the monoclonal antibody is beginning to do its job and the patient's cells are reacting as they should be.

It was also pointed out to me that some monoclonal antibodies are designed to target other factors which some cancers secrete to stimulate the formation of new blood vessels which the cancer cells need to nourish themselves as they divide and grow. Still other "designer monoclonals" for treatment are designed to neutralize proteins in the blood or tissues called "transcription factors," which  attach themselves to cancer cells and stimulate their growth.

I need to read more to learn why researchers can't just make all monoclonal antibodies entirely from human-derived proteins.  But until they do...mouse guts it is.


http://www.nlm.nih.gov/medlineplus/news/fullstory_106833.html