For decades, treatment of leukemia remained the same, but recent research, including promising clinical trials, is providing new hope for patients diagnosed with this cancer or other disorder of the blood cells. That optimism is particularly true for those older patients who were usually not considered good candidates for most treatments.
“The future is bright,’’ said hematologist Dr. Ronan Swords, an assistant professor at the University of Miami’s Miller School of Medicine. “We’re moving toward an era of better treatment.’’
Thanks to a growing understanding of what goes on in both healthy blood cells and leukemia cells, treatment is headed away from chemotherapy toward targeted therapy that is less destructive to the body’s other cells. This is good news for the 52,380 new cases of leukemia that will be diagnosed this year and the other 303,000 living with the disease.
The most common types of leukemia involve one of the two major types of white blood cells: lymphocytes and myelocytes. These cells are important because they help the immune system fight off viruses and infections. Leukemias caused by rogue lymphocytes are called lymphocytic leukemias. By the same token those arising from myelocytes are called myeloid leukemias. In leukemia, the bone marrow makes abnormal white blood cells that often crowd out healthy cells.
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Leukemia can be either acute or chronic and fall into four categories: acute lymphocytic leukemia (ALL), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL) and chronic myeloid leukemia (CML).
Patients with acute leukemia are usually treated right away in an effort to destroy the cells. When the cancer is in remission, maintenance therapy tries to prevent a relapse. Some cases of acute leukemia can be cured. Chronic leukemia can often be controlled, but it is rarely cured by chemotherapy. Some stem cell transplants, however, offer a chance for a cure for chronic leukemia patients.
Chemotherapy for acute leukemia, however, is not without problems, as the treatment also kills healthy fast-dividing cells, including digestive tract cells and hair follicles. What’s more, chemotherapy is considered effective only for patients under 60 years of age and mostly as a way of prolonging survival.
“The types of AML we see in older people is more aggressive,” Swords explained, adding that there is a very low survival rate for AML patients over 70. In patients 60 and younger, there is a 50 to 70 percent chance of remission, but the chances that the cancer will come back are high.
Enter targeted treatment, which blocks the growth of leukemia cells. Currently Swords and his staff are conducting a Phase I clinical trial on a promising drug, MLN4924. It targets a protein that helps leukemia cells grow and divide by “turning it off,” which leads to the death of leukemia cells — without damaging normal cells.
“So far this drug is incredibly safe and patients tolerate it very well,” Swords said.
Swords’ team is also looking at another targeted therapy drug, AG-221, which blocks a mutated enzyme while allowing the immature bone marrow cancer cells to grow normally. An interim analysis showed that out of 10 patients, six had either responded completely or partially to treatment. While MLN4924 is further along in development, AG-221 is providing encouraging results, too, said Swords.
“There are dozens and dozens of targeted treatments in the works and more are coming as we learn more about cancer biology,” he said.
Richard Sanders, 68, of Boynton Beach, is one of those patients who has benefited from novel drug therapy. Sanders suffers from myelofibrosis, an uncommon but serious pre-leukemia bone marrow disorder that disrupts the body’s normal production of blood cells. He is part of a Phase I clinical trial testing KB004, a manufactured antibody which requires a once-a-week, two-hour infusion.
“Up to this point, there was no treatment, no drug on the market for MF,” Sanders said. “This gives me hope.”
Other kinds of leukemia treatment have also progressed. Dr. Krishna Komanduri, head of UM’s Adult Stem Cell Transplant Program, oversees transplants of healthy stem cells — similar to getting a blood transfusion — in patients who have already undergone chemotherapy.
Stem cells can come from the patient, harvested before treatment destroys them, or from a donor, including a family member or an unrelated person. The difference between a bone cell transplant and a stem cell transplant is where in the body the stem cells come from. If collected from the bone marrow, it’s referred to as a bone marrow transplant. If stem cells are taken from the bloodstream, it’s called a stem cell transplant.
Over the past 15 years, scientists have discovered that in allogeneic stem cell transplants, or transplants from a donor, these foreign, donated cells go on to kill the bad cancer cells.
The realization that these donated cells have cancer-killing abilities “is a key to our success because it allows us to dial down the dosage (of drugs used to offset transplant rejection), dramatically reducing toxicity,” Komanduri said. This, in turn, means that patients who would not normally be considered for a transplant can now benefit from the safer approach.
"We are routinely transplanting in older patients,” he added. “This is especially important here because of our demographics.”
Other physicians have widened their approach to leukemia treatment in unusual ways. Oncologist Mike Cusnir of Mount Sinai Medical Center, for example, has been using techniques he learned in a two-year fellowship in integrative medicine in combination with standard medical practices. Integrative medicine incorporates a variety of therapies — including acupuncture, nutrition counseling, exercise programs, tai chi, yoga, guided imagery — to help decrease stress, improve strength and promote relaxation.
Cusnir emphasizes that IM serves as a complement to standard care, not a substitute, but integrative medicine is especially useful for cancer cases, since so many are lifestyle related. Even then reception is mixed.
“There are patients who are right away open to taking the integrated approach,” Cusnir said. “Others are totally closed.”
He admits to resistance from some of his own medical colleagues as well as initial confusion among patients. “What surprises most patients is that I’m not treating the disease,” he added. “Integrative medicine is about treating the whole person, not just the disease. This means treating the mind, body and spirit.”
As hospitals and medical schools adopt the philosophy of this holistic movement, Cusnir predicts more converts. “We are learning that, for treatment, we cannot disconnect the body from the mind.”