Battling bad blood
A new vaccine could be a valuable weapon in helping to slay acute myeloid leukemia in some patients.
And that has some oncologists at the Spectrum Health Cancer Center excited.
“There’s no doubt that this is exciting,” said Stephanie Williams, MD, an oncologist and division chief of the Spectrum Health adult blood and marrow transplant program. “This represents an advance. It’s too early to tell where it will fit into the treatment of patients with leukemia.”
Patients with acute myeloid leukemia—one of the most aggressive blood cancers—typically undergo intense chemotherapy to battle the disease.
The problem is, they almost always relapse within a couple of years, according to senior researcher David Avigan, MD, director of the Cancer Vaccine Program at the Beth Israel Deaconess Medical Center in Boston.
Seventeen patients does not mean a miracle yet. We’re optimistic, though.
According to the American Cancer Society’s 2016 statistics, there were 19,950 people in the United States suffering from acute myeloid leukemia, also known as AML. The disease affects normal white blood cell production.
The five-year survival rate? A shoddy 26 percent.
“That’s why it’s important to develop these new vaccines,” Dr. Williams said.
The anti-cancer vaccine, made from a leukemia patient’s own cells, is showing promising results in early testing. Although only 17 patients have been vaccinated, the vaccine has produced long-term remission for 70 percent of those patients—almost five years.
“These are patients with AML who underwent chemotherapy who went into remission, then were given a vaccine to maintain that remission,” Dr. Williams said. “Vaccines work the best when you have the least amount of disease possible. They really help rev up the immune system. There are also medications out there that try to turn on a patient’s immune system to attack a cancer. This is growing very prominently in the field of oncology.”
Dr. Williams said although the ideas have been around for a long time, it’s just recently that researchers have been able to harness the body’s immune reaction for the benefit of the patient.
But many unanswered questions remain, according to Dr. Williams, such as how long will it last? What are the off-target side effects? Will it affect other organs?
“It’s an evolving field,” Dr. Williams said.
Now, patients who complete successful chemotherapy for acute myeloid leukemia typically receive a bone marrow transplant, in hopes that new white blood cells produced by the donated marrow will seek and destroy the cancerous blood cells circulating in the patient’s body.
Unfortunately, bone marrow transplants sometimes come with unintended consequences. The donated bone marrow can attack the person’s own body. Patients take a strong immune-suppressing drug, which leaves them vulnerable to infections.
Because the new vaccine uses a patient’s own immune cells instead of donated cells, it avoids the sometimes nasty side effects of bone marrow transplants.
“It’s very encouraging and very exciting,” Dr. Williams said. “I think we should be optimistic, but it will take time, research and money for that research to be done. Federal funding and private donations are extremely important. Advances like this can only take place in an environment that encourages and supports research. It will take several more years to test the vaccine further and to develop it.”
Brett Brinker, MD, hematology/oncology physician at Spectrum Health, said the new vaccine is “extremely promising,” but cautioned testing has only been done on a small group of patients.
“Seventeen patients does not mean a miracle yet,” Dr. Brinker said. “We’re optimistic, though.”
Dr. Brinker said the science behind the vaccine is fascinating, harnessing the body’s own immune system to fight the disease.
“AML leukemia cells are always evolving genetically,” Dr. Brinker said. “You can kill off one clone and, as soon as you do, another clone can rear its head and grow. It’s like hitting a moving target. That’s why chemotherapy stops working. Cancer cells mutate and render chemotherapy useless. They learn to go into hiding from the immune system.”
It’s the nature of all living things, according to Dr. Brinker.
“All life wants to go on, even if it’s a cancer cell, it wants to live,” Dr. Brinker said. “Cancer cells want to live as much as a normal cell or the human body does. Leukemia cells have different ways of evading chemotherapy and the immune system. That’s why we need to use different techniques to fool or kill them, like traditional chemotherapy, targeted chemotherapy and vaccine therapy.”
By mixing a patient’s leukemia cells with healthy white blood cells in the body, the vaccine in a sense shines a flashlight on the leukemia cells.
So, the immune system can suddenly detect and fight the leukemia cells.
Dr. Brinker reminds us that this vaccine is only effective battling small amounts of leukemia in patients who have already undergone chemotherapy and are considered in remission.
“This is where we temper our enthusiasm,” he said. “All the patients were in remission when they got the vaccine.”
But, of the 17 patients in the study, 90 percent were still in remission five years out.
“Those are impressive numbers,” Dr. Brinker said. “But there are two points to remember. It’s a small group of patients and those patients were probably going to do better than the average patient anyway (because they were in remission). But, it sounds really promising.”
Even if the vaccine proves effective, Dr. Brinker said it won’t work for all patients. He said some may still do better with bone marrow transplants or other targeted drug treatments.
Dr. Brinker said he’s keeping an eye on the vaccine’s progress.
“This is not ready for prime time,” he said. “We’re kind of waiting to see how this initial trial does. If it looks promising, we’ll work with different groups to try to pull in the trials here at Spectrum Health. We would love this to work. I think it’s very promising.”