Seeking 'precision therapy': Dell Children's steps into global pediatric leukemia trial

After Julie Guillot's son Zach was diagnosed with acute myeloid leukemia in 2010 at age 5, "it was a like a freight train" hit them, she said.

"We were a normal family," she said. "We were living on the lake in Austin; we were living the good life. We had no history of cancer. We tried to do all the right things: eat all organic food, get plenty of exercise."

But then the weird bruising and the random ulcer on Zach's tongue "all just snowballed one day," she said. and he ended up in the hospital with a cancer diagnosis.

During the next four years, Zach endured round after round of chemotherapy. He had three bone marrow transplants.

"It was terrifying," she said, but "Zach had a phenomenal attitude. ... He wanted to live."

After Zach died in 2014 because his liver could no longer take the treatments, Guillot became an advocate with the Leukemia & Lymphoma Society. An engineer by training, she said she is focused on "finding those bottlenecks and choke points" in getting better treatment for kids with cancer.

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With pediatric cancer, some of those choke points are being able to enroll enough children in a trial as well as the focus on trying a new treatment on adults first and children years later. Pediatric cancers, however, aren't the same as adult ones, and each cancer typically has many subtypes that make it respond differently to treatments.

The Leukemia & Lymphoma Society and the National Cancer Institute have begun the PedAL trial (Pediatric Acute Leukemia). It's a global trial that is mapping the genomic makeup of acute leukemias in kids who have had a relapse of that cancer.

The goal of the study "is to characterize leukemia on a level never done before," said Dr. Shannon Cohn, a pediatric hematologist oncologist at Dell Children's Medical Center of Central Texas and an assistant professor at the department of pediatrics at Dell Medical School.

Once the genomic makeup of the cancer is determined, the study participants can opt to enroll in a subtrial with a precision therapy for that genomic type of leukemia.

Dell Children's was the first to enroll a patient in this multinational trial this spring.

"That was a bit of a surprise to me," Cohn said.

The team of researchers was able to get the trial opened and had the perfect candidate for it once it opened, she said.

It's one of 80 clinical trials available at Dell Children's.

"We're a medium-size hospital, but we're in the top quartile of enrolling institutes (for pediatric clinical trials). That shows how dedicated the research team is," Cohn said.

Being a multinational study will be key for the PedAl trial. Dell Children's sees only about 10 cases a year of these kinds of leukemias, Cohn said. Researchers needed to involve many sites to get the numbers for the initial trial and then the subtrials to test different precision therapies.

With pediatric relapsing acute myeloid and relapsing acute lymphoblastic leukemias, "therapeutic options are really limited," Cohn said. "There are not well-known targeted therapies in pediatric leukemia."

Traditional chemotherapies for pediatric leukemia "just kill fast-growing cells," Cohn said. "It's a crude treatment. They come with tons of side effects and aren't tailored for any subtypes."

A targeted therapy, she said, "is much more manageable compared to a very toxic chemotherapy."

Some of these targeted therapies work with antibodies that attack a specific protein, or they might inhibit different growth signals or activate others.

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This study isn't for the child who has leukemia and responds well to chemotherapy and then goes into remission, as do most of the pediatric patients with leukemia.

Instead, it's for those patients who have already gone through chemotherapy, and the cancer returns or never goes away.

"This study is reserved for patients where the options for cure is really limited," Cohn said. "It's patients with a poor prognosis."

She said she doesn't anticipate having trouble persuading patients to enroll in the initial trial to have their cancer typed and then subsequent trials to try a target therapy.

"Most parents whose kids have a poor prognosis would be excited to have an option," Cohn said.

The dream for this trial is that by using the data from around the globe researchers will be able to more clearly identify the subtypes of leukemias and then do the trials for targeted therapies. Once those trials are done, it might eventually be possible to find the genomic makeup of leukemias and start targeted therapy from the beginning rather than waiting for a relapse.

This is also about speeding up how long it takes for pediatric cancer therapies to be approved, Guillot said.

"Zach didn't get to have precision therapy," Guillot said. "We know it can work when you can hit the target."

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This article originally appeared on Austin American-Statesman: Dell Children's steps into global pediatric leukemia trial