Fighting Disease With DNA

Doctors can use your genes to detect the best treatment for your body.

January 8, 2009, 1:11 AM

Aug. 22, 2007 — -- By the time Jacob Flood turned 2, his mother, Marla Flood, knew something about him was different.

"It was pretty much said, you know, 'He's splitting off. He's splintering off, developmentally," Flood said. "'I think he has autism.' And, of course, mom didn't take that very well."

Watch the second part of the gene series tonight on "World News with Charles Gibson."

Within a year, Jacob was put on medication for his autism. But over the years, his behavior only seemed to get worse.

"He would get to the point where he was extremely physically aggressive towards myself, my husband, my kids. He would bite, pinch, pull hair. He would hit," Flood said.

Flood, her husband and other children ended up with bruises on their arms.

Prescribing the right drugs was a "guessing game," she said, because Jacob isn't able to communicate well. "He can't tell me when 'this medicine is making my body shaky, or it's giving me a headache, or it's making me feel like I'm going to throw up.'"

So, two years ago, Jacob's doctor tried something new and innovative. Jacob, who is now 11, was given a genetic test to find out how his body was processing the autism medicines he was on.

The results were startling.

"We realized we overdosed him," said Dr. Patty Manning-Courtney, of Cincinnati Children's Hospital Medical Center, "and he got worse, because we gave him too much of what we thought was a good thing."

Cincinnati Children's Hospital currently offers testing for two genes to all children and adults admitted to the hospital who receive psychiatric medicines.

The test involves gauging the way individual people's livers metabolize medicines.

And Jacob's mother said that while the new lower-dose prescription did not cure her son's autism, he's now a "different kid."

"We saw a big change. We saw less aggressiveness," Flood said. "He still screams, and he stills get mad, and he still has some aggressive behaviors, but they're nothing like they were before."

Right now, pharmacogenetics, as the field is called, is in its infancy. Only certain hospitals offer the kind of testing Jacob received to help doctors tailor treatment for individual patients. But eventually, doctors hope the practice will spread.

"I do envision in the next five to 10 years, the number of genes we'll test will grow immensely, and the number of opportunities for patients to get more personalized care, will grow immensely," said Dr. Tracy Glauser, co-director of the Genetic Pharmacology Service at Cincinnati Children's Hospital.

At Duke University in North Carolina, doctors are running a cutting-edge experiment. They are analyzing the DNA of individual cancer tumors to determine the best type of chemotherapy regimen to use in fighting that particular person's lung cancer.

As many as a quarter of lung cancer patients may be resistant to standard chemotherapy, experts say.

"We know that for people with advanced lung cancer our standard treatment is a combination of a platinum drug plus another type of chemotherapy.  Unfortunately, we don't know for each individual patient, which drug combination is going to work best," said Dr. Jennifer Garst, associate professor with the Albert Thoracic Oncology Program at Duke University Health Systems. 

"So, it's sort of like treating pain.  Some people do well with Advil. If Advil doesn't work, we switch to Tylenol.  If Tylenol doesn't work well, we may have to switch to narcotics.  It's sort of the same thing with treating lung cancer," Garst said.

In the Duke study, they are analyzing more than 40,000 genes and using a mathematic, predictive model to figure out whether a patient will be sensitive to particular drugs.

Choosing the best treatment is particularly important for lung cancer because the first round of treatment can be critical.

"The first time we treat patients is their best chance in terms of getting shrinkage of their tumor," Garst said.

One of their patients Cyndee Sessoms is a single mom with an 11-year-old daughter. An avid tennis player, she was shocked when she was diagnosed with stage four lung cancer.

"I think I was emotionally paralyzed. You can't really put words to those kinds of emotions.  I didn't cry. I think I emotionally was just frozen," Sessoms said.

Now Sessoms is part of the Duke study and she hopes it will help her fight the disease for as long as possible.

"I think it was an answer to a prayer because I didn't know that anything like that was available," she said.

Tailoring treatment by using genetic testing is not cheap. The testing can cost between $300 and $1,000.

Many doctors say it would not be economical to use it on all patients at this stage. But in limited cases, advocates say it can be a lifesaver.

"This could be a true revolutionary step for how clinicians pick medicines and adjust their doses," Glauser said. "We're not there yet — this is just the first step in what should be an exciting process over the next four years."

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