TV celebrity Suzanne Somers was treated for breast cancer herself, and has openly spoken about what she called the “vast and often pointless use of chemotherapy” (Huffington Post, 2009). This comment refers to the great suffering inflicted on many women by the side effects of chemotherapy, when the therapeutic gain in extended lifespan is minimal.
Chemotherapy drugs are nonspecific to cancer, and also attack other cells that are rapidly dividing. Most of these cells are hair and skin cells, or cells found in the stomach lining. The chemotherapy attack on these healthy cells causes the side effects characteristic to of this form of treatment (nausea, vomiting, hair loss, etc).
The solution to the problem of the  nonspecificity of chemotherapy is making chemo drugs more targeted directly at the tumor cells, if possible. One way to do this is by linking or conjugating a potent chemotherapy drug to an antibody custom-targeted at cancerous tumor cells. Most monoclonal antibodies tested as drugs don’t turn out to be very effective. But, as Clay Seigall – the CEO of Seattle Genetics – points out, “Drug conjugates can empower an antibody. The vast majority of antibodies are just not very potent on their own.”
At this year’s ASCO meeting being held right now in Chicago, a new drug in Phase III development at Genentech named TDM-1 combines the potency of chemotherapy mertansine with the specificity of an antibody to the Her2 protein implicated in many breast cancers. The title of the presentation that reveals late stage clinical trial data for TDM-1 is, “Hitching a ride on a therapeutic antibody,” presented by Dr. Howard Burris. With this novel approach to treating cancer, chemotherapy is considered the hitchhiker being ferried to the cancer cell by the anti-Her2 antibody to knockout the malignant cell.
Sources: Huffington Post, Pharmalicensing.com, asco.org
