Experimental leukemia treatment results in astonishing cure
Rarely does a novel cancer treatment produce a sensational result – until today. Researchers on the outer margins of experimental cancer treatment have designed a shockingly successful gene therapy treatment for leukemia. In a surprising twist, an inactivated form of the HIV virus has proven to be a key player in the cure.
The researchers have so far treated only three patients, but the sensational results from a single shot could be one of the most significant advances in cancer research in decades. And they almost didn’t get the money even for this ultra-small experiment.
The research is being published today simultaneously in the New England Journal of Medicine and Science Translational Medicine. The treatment made the most common type of leukemia completely disappear in two of the patients and reduced it by 70 percent in the third. In each of the patients, as much as five pounds of cancerous tissue completely melted away in a few weeks. Most impressively, the cancer is gone a year after treatment.
Doctors at the University of Pennsylvania targeted a leukemia called chroniclymphocytic leukemia (CLL), the most common type of the blood disease. It strikes some 15,000 people in the United States annually, mostly adults, and kills 4,300 every year. Chemotherapy and radiation can hold this form of leukemia at bay for years, but until now the only cure has been a bone marrow transplant. That exceedingly painful and risky procedure requires a suitable match, works only about half the time, and often brings on severe, life-threatening side effects such as pain and infection.
In the Penn experiment, the researchers removed certain types of white blood cells that the body uses to fight disease from the patients. Using a modified, harmless version of HIV, the virus that causes AIDS, they inserted a series of genes into the white blood cells. These were designed to make the cells target and kill the cancer cells. After growing a large batch of the genetically engineered white blood cells, the doctors injected them back into the patients.
Similar past experiments have been conducted unsuccessfully because the white blood cells would die out very soon after attacking a few cancer cells. The Penn researchers addressed the problem by inserting a gene which allowed the white blood cells to multiply wildly inside the body. The white cells then became what Dr. Carl June, one of the scientists involved in the treatment, voracious “serial killers” of the cancer cells, relentlessly tracking down and killing them in the blood, bone marrow and lymph tissue.
The dramatic kill-off appeared to kick in on Day 14 after the initial infusions. A patient came down with chills, a fever and nausea – essentially the worst case of the flu, symptom-wise. While researchers initially worried that the symptoms were signs of worsening leukemia, it turned out they were just the opposite. The patient's tumor "was blown away" almost all at once, Dr. June said.
The primary reason for that dramatic effect was that when the genetically engineered cells found their target, they multiplied more than 1,000 fold, essentially mobilizing a huge army of cells, which then attacked the tumor cells.
On the 28th day after treatment, the side effects from the treatment subsided. In addition, researchers could find no evidence of leukemia in the patient's blood or in the bone marrow.
Besides the extreme flu symptoms and signs of acute kidney damage, the treatment kills off the body’s B cells. This can be managed medically. Dr. June cautioned that the treatment needed to be tried on many more patients before its value, or how it works, is well understood. "We're going to find out how well these principles apply to tumors other than leukemias," he said.
The amazing treatment almost never came to pass. Both the National Cancer Institute and several pharmaceutical companies declined to pay for the research. Neither applicants nor funders discuss the reasons an application is turned down. But good guesses are the general shortage of funds and the concept tried in this experiment was too novel and, thus, too risky for consideration.
It was the Alliance for Cancer Gene Therapy (ACGT), a charity founded by Barbara and Edward Netter after their child died of cancer, which finally provided the research team with a small grant, and which enabled the scientists to treat just three individuals. It is likely that now, after the publication of these findings, money for further studies -- not just in this one type of leukemia, but in other cancers -- will likely pour in from both the government and drug companies.
You can access the New England Journal of Medicine brief about the experimental findings here.
You can also watch a video report from NBC News below.
The mission statement of ACGT states that it supports the extraordinary potential offered by cell and gene-based therapies to accelerate effective and safe treatment of all types of cancer. It awards just a handful of grants each year to the most promising, cutting-edge research proposals. Most grants are under $1 million, and many are just $250,000.