Promising gene therapy for brain illness to begin

6/5/2001

GIBSONBURG - Doctors in Philadelphia will insert a manmade gene into the brains of three children today, hoping it some day will stop a progressive, fatal illness that kills most of its victims before they're teens.

The clinical trial, which has waited more than a year for approval, is the only one trying to find a cure for Canavan Disease. The parents see it as their children's only hope.

Brianna Burkett of Gibsonburg has been fighting the illness all six years of her life. It has made her blind, given her dangerous seizures, and robbed her of the ability to speak or walk.

But while she is enrolled in this program, she and 11 others will not be treated today. Researchers say there is no more money.

“We are hoping to speed it up. We really have a commitment to these kids, and we want to see all of the children treated. But to get just to this point with the gene therapy has cost us about $1 million. We don't have the money,” said Dr. Helene Karlin, whose daughter, Lindsay, will be treated today.

Ms. Karlin and her husband started the Canavan Research Foundation to raise money for the treatment.

The fight for this treatment has been an emotional roller coaster ride for Brianna's mom, Yulinda, and the parents of the other children.

For nearly three years they have battled medical bureaucracy and a fear of gene therapy - fueled by the death of an 18-year-old in a treatment program - to get the Food and Drug Administration's go-ahead on the procedure.

For the last year, the FDA required more information and more testing from the researchers. The treatment was scheduled, then canceled twice in May.

Because Canavan is an “orphan disease,” meaning it affects only a few people, the treatment program is funded only by parents and donations to an organization they founded to raise money, the Canavan Research Foundation. The scrutiny over the program forced the group to spend almost all of its money - about $1 million - on testing and research.

Ms. Karlin said it will take about $1 million more to treat the rest of the kids. That does not include the costs of testing and other care that the parents have to pay, which Ms. Burkett said could add up to $54,000 per child.

Meanwhile, the parents keep a weary eye on the children, who have lost ground since the last treatment in 1998 against a disease that interferes with the brain's communication with the rest of the body.

“Time is absolutely of the essence here,” Ms. Burkett said. “Every day these kids lose one way or another. Every day is a day we didn't have to waste, really.”

Canavan is a rare illness that causes a defective gene to keep the body from producing myelin, or the white matter in the brain. This myelin coats the nerves and allows messages to be sent to the spinal cord and other parts of the brain.

Without myelin, the brain's communication system doesn't work like it should. The children can't speak; most can't walk. Their muscles are either stiff as a board or limp like a rag doll. Eventually, they can't swallow and have to be fed through a tube.

The idea behind the gene therapy is to inject a good gene into the brain, where the disease occurs, and hope it does the work of the defective gene.

In a phase one clinical trial in 1998, doctors injected the gene into the brains of Brianna and some other children. It had only been done once before, in New Zealand in 1996.

A phase one clinical trial meant it was designed to test the safety of the procedure. Any benefit to the children would be an added bonus. Still, parents and doctors of the children reported improvement in motor skills and general health. Brianna could hold her head up for the first time, and she could see so well that her mother bought her glasses.

But the problem was the gene could not reach many parts of the brain, so it had limited value. So researchers scrapped the program and threw all their money into the procedure being used today.

Doctors at Thomas Jefferson University Hospital in Philadelphia plan to put the gene into what is called an adeno-associated virus. The idea is that a virus, like the common cold, travels throughout the body so it would reach more parts of the brain.

The last treatment could reach about 100,000 cells; this one could reach well over 2 million.

This is the first time that this nonpathogenic viral vector will be delivered to the brain for gene therapy, according to Meryl Latsko, clinical research coordinator for the university's gene therapy center. She said if successful, the treatment could be used for other neurological diseases.

Researchers said they hope to treat five to seven children each year in the three-year trial. Doctors and the FDA determine which kids will be treated first.

That has to do with a lot of factors, including age and health.

Ms. Karlin and her husband, Roger, were one of two couples who took their children to New Zealand to get the treatment in 1996. They were in from the beginning and urged the researchers to get the procedure approved in the United States. Their daughter Lindsay has been in on each step of the trials.

Ms. Karlin said at 6 years old Lindsay is relatively healthy and ready for the treatment. Like Brianna, she has been losing the gains she made after the last treatment.

“She's very stable. The FDA wanted some of the older children to go first,” Ms. Karlin said.

Brianna has had her share of health problems lately. In May, she had a seizure at a fund-raising event and had to be rushed to the hospital. It was the first time her mother had to call an ambulance for her.

Ms. Burkett and Brianna's doctor fear the little girl is deteriorating much more rapidly lately. Her seizures are more frequent. She's irritable - a sign she's sicker than before - and her vision is bad again.

Her mother has been having fund-raisers and is selling soda at this month's homecoming in Gibsonburg so she'll be ready when Brianna's turn comes. She sees today's procedure as a sign that things are progressing.

“They've been waiting so long for this. Whether Brianna is on the list or not, I'm very excited it's starting,” she said.