Cautious Optimism On Novel Gene Therapy Cure For Leukemia

A very small study involving three patients receiving a novel gene therapy treatment appeared to cure two patients completely of a common form of leukemia. The third patient showed significant improvement.

I'm stressing the small size of the study, because such results might not be found when applied to a larger group and that many additional studies will be needed to confirm the early findings.

"It worked great. We were surprised it worked as well as it did," said Dr. Carl June, a gene therapy expert at the University of Pennsylvania. "We're just a year out now. We need to find out how long these remissions last."

He led the study, published Wednesday by two journals, New England Journal of Medicine and Science Translational Medicine.

It involved three men with very advanced cases of chronic lymphocytic leukemia, or CLL. The only hope for a cure now is bone marrow or stem cell transplants, which don't always work and carry a high risk of death.

Scientists have been working for years to find ways to boost the immune system's ability to fight cancer. Earlier attempts at genetically modifying bloodstream soldiers called T-cells have had limited success; the modified cells didn't reproduce well and quickly disappeared.

June and his colleagues made changes to the technique, using a novel carrier to deliver the new genes into the T-cells and a signaling mechanism telling the cells to kill and multiply.

That resulted in armies of "serial killer" cells that targeted cancer cells, destroyed them, and went on to kill new cancer as it emerged. It was known that T-cells attack viruses that way, but this is the first time it's been done against cancer, June said.

For the experiment, blood was taken from each patient and T-cells removed. After they were altered in a lab, millions of the cells were returned to the patient in three infusions.

The researchers described the experience of one 64-year-old patient in detail. There was no change for two weeks, but then he became ill with chills, nausea and fever. He and the other two patients were hit with a condition that occurs when a large number of cancer cells die at the same time — a sign that the gene therapy is working.

"It was like the worse flu of their life," June said. "But after that, it's over. They're well."

The main complication seems to be that this technique also destroys some other infection-fighting blood cells; so far the patients have been getting monthly treatments for that.

Penn researchers want to test the gene therapy technique in leukemia-related cancers, as well as pancreatic and ovarian cancer, he said. Other institutions are looking at prostate and brain cancer.

This study should spur investment and research at utilizing similar treatments for other common cancers.

While the imminent side effect of a bad flu lasting a week or so would be a vast improvement over the kinds of side effects from current treatment options, that include everything from prolonged weakness, hair loss, organ failure, auto-immune disorders, among others, that other immune cells are affected might have long-term consequences that need to be studied as well.

These patients will need to be studied over the next couple of years to see if their cancer remains in remission or if there are thus-far undiscovered side-effects such as other forms of cancer or illnesses that result from the gene therapy.

Still, that this development is going to spur investment and research on this technique is a major breakthrough and here's hoping that the results hold up.