Gene therapy beats skin cancer in two men: study

By Lisa Richwine

WASHINGTON (Reuters) – Genetically altered immune cells
wiped out tumors in two men with a deadly form of skin cancer
and kept the patients disease-free for at least 18 months, U.S.
scientists said on Thursday.

Fifteen patients did not respond to the treatment, however,
and the researchers and other experts said more work was needed
to make it more effective.

Still, the findings were welcomed as evidence that cancer
patients can be successfully treated using gene therapy, a
troubled field that has been hindered by safety concerns.
Scientists voiced hope the approach could work for other
cancers.

In the new study, researchers at the National Cancer
Institute (NCI) infused 17 advanced melanoma patients with
their own white blood cells that had been removed and
genetically engineered to fight tumors. The cancer was
eliminated in two male patients, the researchers said.

“The tumors went away and both of the patients are now
completely disease-free over a year and a half later,” Dr.
Steven Rosenberg, chief of surgery at the NCI, said in an
interview.

Before the experiment, the patients had advanced skin
cancer that was not helped by standard therapies and they were
expected to live just three to six months, he said.

Writing in the journal Science, the researchers said the
white blood cells had been armed with genes to spark production
of proteins called T-cell receptors. Those receptors recognized
molecules on the melanoma cells and directed the white blood
cells to destroy the cancer, they said.

DISEASE-FREE 18 MONTHS LATER

In a 52-year-old man, a tumor in his armpit disappeared and
another on the liver shrunk enough to be surgically removed. He
remained disease-free 19 months after treatment, the study
said.

Another patient, a 30-year-old man, had a lung tumor recede
and showed no signs of disease 18 months later.

Other gene therapy researchers said the results were a
major step forward, but the technique needed to be improved so
more patients would benefit.

“This certainly is a significant technical advance that is
going to fuel more interest … and more enthusiasm, I hope,
among researchers,” said Dr. Michel Sadelain, director of
Memorial Sloan-Kettering Cancer Center’s somatic cell
engineering laboratory.

But he added it was “undeniable the response here is rather
disappointing.”

Savio Woo, a professor at Mt. Sinai School of Medicine and
a past president of the American Society of Gene Therapy said
the researchers “need to do it in more patients and get better
response rates, and when that happens we can all pop the
champagne.”

Scientists have touted gene therapy as holding great
promise for a range of ailments, but safety problems have set
the field back. One experiment cured two French “bubble boys”
with a rare immune disorder, but later gave them leukemia, and
an 18-year-old died in a 1999 gene therapy experiment.

Rosenberg said there were no side effects from the melanoma
gene therapy. It was administered with the drug interleukin-2,
which can cause fluid retention, he said.

The researchers said they hope the same approach can fight
breast, lung and other cancers. They are seeking regulatory
approval to test the technology in patients with other cancers,
Rosenberg said.