by: Laurie Johnson, February 22, 2006 12:02:00 am
The idea of using T-cells as therapy is similar to a vaccine. Doctors can extract diseased cells from the body, multiply and manipulate them in the lab and reinject them back into the patient. Then the body's immune system kicks in, attacking the manipulated cells along with all the other cells that look the same and carry the disease mutations. Dr. Cliona Rooney is a professor in the department of pediatrics at Baylor College of Medicine. Her research focuses on using this therapy against various types of cancer.
"The nice thing about a T-cell is that, unlike a drug, it is incredibly specific. So it's very very specific for a short peptide that is expressed in the tumor so it's not going to do any by-stander damage -- so it'll go and find the tumor and kill it and it won't kill any other cells. So that's the really nice thing about T-cells. The other nice thing is T-cells are not inert; so they can actually travel through the body and they follow signals and they can find tumors which are buried deep within tissues."
A Houston company is also using this theory to attack multiple sclerosis. PharmaFrontiers is a publicly traded company working to market a vaccine called Tovaxin. Company CEO David McWilliams says MS is a very difficult disease to study because it relapses and remits, but their success rates in clinical trials are high.
"The way in which one typically measures a therapeutic benefit in Multiple Sclerosis is a reduction in the relapse rate, which means that a patient's -- you know stay on a level course and don't relapse into the disease, which they do typically in the earlier stages. We are now up to a 93 percent reduction in our most recent trials."
That's an enormously high success rate with significant improvement since the initial tests began in the '90s. Dr. Rooney cautions it can be hard to tell whether the improvements are directly related to the vaccine or to the idiosyncracies of the disease. She says one of the problems with T-cell therapy is very specific and can take as long as three months to develop for a single patient.
"It's never going to be off the shelf, it's never going to be, you know, a vaccine for millions of people. It's going to be something that's, that's highly specialized -- it's more like surgery, if you like. You know it takes, it takes a lot of time -- it has to be individualized for each patient."
Dr. Rooney has about ten clinical trials underway using T-cell therapy in cancer treatments. The trials are a collaboration between Baylor College of Medicine, The Methodist Hospital and Texas Children's Hospital. PharmaFrontiers is conducting clinical trials on MS patients, and was recently approved for research into therapy on rheumatoid arthritis patients. They expect to begin human testing by the end of this year. McWilliams says it will be another four years or so before the MS vaccine is ready for federal approval. Laurie Johnson Houston Public Radio News.