(Photo: Margaret Showel, hematologic oncologist at the Kimmel Cancer Center)
An estimated 60,000 Americans will be diagnosed this year with leukemia, a cancer of the blood cells that starts in the bone marrow.
Leukemia can grow aggressively, it is often resistant to treatment and it has a high rate of relapse. Since it is a disease of the blood, it can affect nearly any organ. Cases can be acute or chronic.
The Johns Hopkins Kimmel Cancer Center at Sibley Memorial Hospital gives patients with leukemia a treatment plan tailored to their individual case. Each treatment plan is developed with input from physicians in various medical specialties. For relapsed, treatment-resistant or difficult cases, experts from disciplines throughout the Johns Hopkins system meet weekly to discuss the best treatment path.
Therapies that Johns Hopkins expert use to treat patients include the center’s innovative bone marrow transplant program, as well as clinical trials for new drugs. Chemotherapy is the mainstay of leukemia treatment. Surgery and radiation are considered in rare instances as supportive therapy.
Clinical trials for new therapies are used for initial treatment as well as relapsed and treatment-resistant leukemia. The therapies include adoptive T-cell therapy, which works by retrieving the white blood cells in cancerous bone marrow that help fight infection and re-infusing the cells after coating them with proteins that activate the immune system to destroy cancer cells.
With leukemia’s high rate of relapse, long-term, low-dose therapy known as maintenance therapy plays a prominent role in keeping patients in remission. At the Kimmel Cancer Center, these trial treatments are often integrated with bone marrow transplants, which can increase survival rates.
The Kimmel Cancer Center is a national leader and one of the country’s few centers that specialize in haploidentical transplantation, a bone marrow transplant procedure that greatly expands the donor pool.
This donor program can use half-matched relatives and can find a donor for almost every patient, says Margaret Showel, a hematologic oncologist at the Kimmel Cancer Center. Biological parents and children are always half matches, and siblings have a 25% chance of being a full match and a 50% chance of being a half match. Nieces, nephews and cousins can also be half matches.
Outcomes with this procedure are comparable to full-match transplantations, which often require a lengthy search for a relative or unrelated donor with all of the same protein markers in their tissue. Since leukemia can relapse quickly, Showel says time is of the essence.
The transplants are performed at the Kimmel Cancer Center’s Bone Marrow Transplant Program in Baltimore. Part of the pre- and post-transplant care is provided in the Washington area.
Johns Hopkins has performed more than 600 haploidentical transplants for adult and pediatric patients with leukemia and lymphoma since developing the procedure more than 10 years ago.
For patients who relapse after transplants, clinical trials provide new therapeutic options. Some patients may benefit from CAR T-cell therapy, a type of T-cell therapy in which a patient’s T cells are genetically modified to target components of white blood cells that normally alert the immune system to destroy abnormal or infected cells.
Another option for leukemia that relapses after a transplant is donor lymphocyte infusions, during which the transplant donor’s white blood cells are infused into the patient’s bloodstream.
These therapies and clinical trial drugs can be valuable options for people with relapsed and treatment-resistant leukemia, and they are increasingly used as part of initial treatment regimens as well.
“These drugs are improving outcomes and they’re often not as toxic,” says Showel, assistant professor of oncology at the Johns Hopkins University School of Medicine. She adds that because Johns Hopkins is a large academic center, it has a large portfolio of clinical trials. “That’s only going to increase,” she says.
Sibley Memorial Hospital has a nine-bed hematologic malignancy inpatient service, which is staffed by physicians, nurses and a pharmacist who specialize in treating leukemia and lymphoma.
“One of the big things about leukemia is these acute cases require urgent care,” Showel says. “We’re available 24/7 to admit patients and start treatment. We have all these resources available and are ready to go here at Sibley.”