Gene therapy brings big hope in war on cancer
American doctors report stunning success in 'living drug' that transforms patients' blood cells into agents that seek and destroy disease
In one of the biggest advances against leukemia and other blood cancers in many years, doctors are reporting unprecedented success by using gene therapy to transform patients' blood cells into soldiers that seek and destroy cancer.
A few patients with one type of leukemia were given this one-time, experimental therapy several years ago and some remain cancer-free. Now, at least six research groups have treated more than 120 patients with many types of blood and bone marrow cancers, with stunning results.
"It's really exciting," said Dr Janis Abkowitz, blood diseases chief at the University of Washington in Seattle and president of the American Society of Hematology. "You can take a cell that belongs to a patient and engineer it to be an attack cell."
In one study, all five adults and 19 of 22 children with acute lymphocytic leukemia, or ALL, had a complete remission, meaning no cancer could be found after treatment, although a few have relapsed since then.
These were gravely ill patients out of options. Some had tried multiple bone marrow transplants and up to 10 types of chemotherapy or other treatments.
Cancer was so advanced in eight-year-old Emily Whitehead of Philipsburg, Pennsylvania, that doctors said her major organs would fail within days. She was the first child given the gene therapy and shows no sign of cancer nearly two years later.
Results on other patients with myeloma, lymphoma and chronic lymphocytic leukemia, or CLL, was reported at the hematology group's conference last weekend in New Orleans.
Doctors say this has the potential to become the first gene therapy approved in the United States and the first for cancer worldwide. Only one gene therapy is approved in Europe, for a rare metabolic disease.
The treatment involves filtering patients' blood to remove millions of white blood cells called T-cells, altering them in the lab to contain a gene that targets cancer, and returning them to the patient in infusions over three days.
"What we are giving essentially is a living drug", permanently altered cells that multiply in the body into an army to fight the cancer, said Dr David Porter, a University of Pennsylvania scientist who led one study.
Several drug and biotech companies are developing these therapies. Penn has patented its method and licensed it to Switzerland-based Novartis. The company is building a research centre on the Penn campus in Philadelphia and plans a clinical trial next year that could lead to federal approval of the treatment as soon as 2016.
Talking with the researchers, "there is a sense of making history ... a sense of doing something very unique," said Hervi Hoppenot, Novartis Oncology, the division leading the work.
The treatment can cause severe flu-like symptoms and other side effects, but these have been reversible and temporary.
Penn doctors have treated the most cases, 59. Of the first 14 patients with CLL, four had complete remissions, four had partial ones and the rest did not respond. But some partial responders continue to see their cancer shrink a year after treatment.
At the National Cancer Institute, Dr James Kochenderfer and others have treated 11 patients with lymphoma and four with CLL, starting roughly two years ago.
Six had complete remissions, six had partial ones, one has stable disease and it's too soon to tell for the rest.
Ten other patients were given gene therapy to try to kill leukemia or lymphoma remaining after bone marrow transplants. These patients got infusions of gene-treated blood cells from their transplant donors instead of using their own blood cells. One had a complete remission and three others had significant reduction of their disease.
Patients are encouraged that relatively few have relapsed.
"We're still nervous every day because they can't tell us what's going to happen tomorrow," said Emily's father, Tom Whitehead.
Scientist Doug Olson, 67, shows no sign of cancer since gene therapy in 2010 for CLL he had had since 1996.
"Within one month he was in complete remission. That was just completely unexpected," said Porter, his doctor at Penn.