Dr. Jeffrey Jones
Though blood cancers such as leukemia and lymphoma have long stymied researchers searching for a cause, treatment is another matter, and innovations in disease management options are advancing on the cutting edge of today’s cancer research.
“People tend not to understand that you can have a cancer of blood cells,” says Dr. Jeffrey Jones, a specialist in hematology at The Ohio State University Wexner Medical Center. “Or that it’s an extensive, systemic disease.”
Unlike solid tumors that usually occur primarily in a single site and have the propensity to metastasize, many blood cancers are systemic cancers from the beginning.
“Leukemia is in your blood,” says Jones. “It’s everywhere.”
Leukemia occurs when cancerous cells are in a patient’s blood and bone marrow. Lymphoma occurs when the problem is primarily in the cells that reside in lymph nodes and, secondarily, in the blood or bone marrow.
For many years, the best treatment for blood cancers was thought to be a combination of drug therapy and chemotherapy, which imposed non-overlapping, often debilitating side effects including nausea, fatigue, depression, hair loss and infertility.
“Increasingly, we’re coming up with chemo-free alternative treatments,” says Jones. “It’s really been an interesting time in leukemia and lymphoma research.”
In the last few decades, immunotherapy has become an important part of treating some types of cancer. Over the past 10 years, a class of drugs known as immune checkpoint inhibitors has seen great success in clinical trials addressing lung cancers and melanomas, with one lung cancer study ending a full two years early after all 107 patients experienced a plateauing of their disease.
Immune checkpoint inhibitors work by escaping notice from the immune system, thus evading a combative response from the body and gaining the ability to work from inside the immune system to trigger the attack of cancerous cells. Until recently, options for the treatment of blood cancers did not include the highly effective immune checkpoint inhibitors.
In May, the drug Opdivo (nivolumab) was approved for the treatment of patients with relapsed Hodgkin’s disease, a cancer of the lymph system, which is part of the immune system. Opdivo is the only immuno-oncology agent to receive eight approvals in less than two years in four distinct cancer types, encompassing three solid tumors, and now, for the first time, it’s expanding to hematologic malignancies.
“It’s miraculous for patients who have relapsed after bone marrow transplants,” says Jones.
In the 1990s, after decades of trying different combinations of drug and chemotherapies, scientists began to understand the underlying genetic mechanisms causing some of these cancers. In the case of some blood cancers, the genetic rearrangement causing problematic cellular abnormalities was found to be growth proteins stuck in an “on” position.
These proteins became targets for drug therapy research.
“The birth of Gleevec really ushered in a new era of investigation in blood cancer medicine, as did the understanding that immune system modifying therapy was the other great innovation,” says Jones.
Gleevec (imatinib), a tyrosine-kinase inhibitor introduced in the U.S. in 2002, turns “off” an overactive tyrosine kinase enzyme. It was the first example of a drug approved by the Food and Drug Administration that targets an intracellular signaling molecule in cancer therapy.
When Gleevec is taken orally, the cancer can be controlled – often indefinitely. The five-year survival rate for chronic myeloid leukemia (CML) patients has increased from 31 percent to 89 percent since 2001.
“By themselves, many of these drugs don’t seem to be a potential cure, but patients can control their disease, some for decades, and sometimes can stop taking it for a time,” says Jones.
Jones’ enthusiasm about the promise of drugs such as Opdivo for the blood cancer community is evident.
“This is the first time one of these immune inhibitors has been approved for treatment of a blood cancer. It’s not targeting the cancer, it’s targeting the immune system,” he says. “This has been really remarkable.”
Jessica Williams is a contributing writer. Feedback welcome at gbishop@cityscenemediagroup.com.
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