Parents of boys with a condition called X-linked severe combined
immunodeficiency now lack even that unenviable choice.
After learning that a second French boy apparently cured of
SCID by gene therapy has developed leukemia, French and U.S. regulators
both suspended trials aimed at using gene therapy to cure the
rare condition.
They will stay closed until scientists can determine what the
risk of cancer is and whether the treatment caused it.
Some parents whose children face death in the interim are furious,
said Barbara Ballard of the SCID Alliance, which represents parents
of children with the rare disease.
"One in particular is extremely upset," Ballard, who routinely
testifies at government hearings, said in a telephone interview
on Wednesday. "It is a case where the child has had several bone
marrow transplants and lives in isolation. This was their first
true hope."
X-SCID patients, sometimes called "bubble boys," are born with
a genetic defect that leaves them without an immune system. If
they have a brother or sister to provide a bone marrow transplant,
their chances are good.
Without treatment, they are vulnerable to any passing infection
and usually die by the time they are 1 year old.
Ballard's son, now 9, doesn't have a sibling. She donated her
bone marrow for a transplant, but a parent is not a good match
and her son still lacks the ability to make antibodies key to
fighting infections.
He cannot be vaccinated and gets monthly infusions of immune
globulin, a blood product that itself carries risks.
LIFESAVING TREATMENT LEFT BOY DEAF
"Half the winter he spends on antibiotics," Ballard added. "He
was made deaf by one of the antibiotics he had to be on as a baby.
It saved his life but he's deaf. That is what you are dealing
with when dealing with a chronically ill child."
Ballard would consider gene therapy for her son if a trial opened
for which he was eligible. Three experiments were under way or
starting in the United States to treat X-SCID before French researchers
reported the first leukemia case in a SCID patient in September.
On Tuesday, the U.S. Food and Drug Administration (news
- web
sites) announced a second child in France apparently cured
of SCID by gene therapy had developed leukemia. Both boys are
being successfully treated with chemotherapy -- leukemia in children
is 90 percent curable -- but regulators in both countries halted
similar trials until they can decide what the risk is.
An emergency meeting of government regulators scheduled for
Friday has been postponed, and regular hearings on the issue are
not scheduled until the end of February.
"The FDA is being cautious and I think that is good," Ballard
said. "We want someone being cautious for us. We want someone
looking at the details. But at the same time we don't want to
throw the baby out with the bathwater," she added.
She pointed out that seven children from the French trial are
leading apparently normal lives, free of both SCID and of leukemia.
"Leukemia is nothing to laugh at -- it is horrendous for the families
involved. But it doesn't mean that gene therapy can't still work."
BIG ALARM
Abby Meyers, president of the National Organization for Rare
Disorders, was less optimistic.
"I think it raises a big alarm and I think it is a big lesson
to the scientific community and the patient community that when
a new technology arises, it takes years and years," said Meyers,
who has three children with genetic disorders.
Some parents would want to go ahead with the gene therapy no
matter what, said Dr. Jonathan Goldsmith, medical director of
the Immune Deficiency Foundation in Towson, Maryland.
"I think it is up to patients and families to make those tough
decisions about the risk-benefit ratio. I will assure you there
are families who will assume that risk," Goldsmith said.
The FDA's Dr. Philip Noguchi said the agency may consider allowing
gene therapy experiments to proceed on a "compassionate basis"
-- when children will die without the treatment.