New research illustrates that some patients with transformed lymphoma showed "remarkable" response to lenalidomide, an oral drug with few side effects.
The international study, involving 24 medical centers in the United States and Europe, will be presented at the American Society of Clinical Oncology annual meeting June 4-8, 2010, in Chicago.
Forty-five percent of patients with transformed lymphoma treated with lenalidomide responded positively to this immunomodulatory medication, which kills lymphoma cells by activating the body's natural killer cells and by interrupting cancer cell signaling that leads to cell death. Of those patients, 21 percent showed complete remission, some for more than a year.
Transformed lymphoma is an aggressive form of blood cancer. With current therapies, patients have a median survival rate of 1.7 years. In comparison, patients with indolent or slow-growing lymphoma can live 10 to 20 years with the disease. However, over the course of a decade, about 30 percent of those with indolent lymphoma develop transformed lymphoma.
"The study results show a remarkable response rate for transformed lymphoma patients who have a very poor prognosis," says Craig Reeder, M.D., Mayo Clinic hematologist and principal investigator for the phase II study at Mayo Clinic's Arizona campus. Phase II studies typically include no more than 300 patients and are designed to evaluate the effectiveness of a specific therapy.
The study included 217 patients with aggressive lymphoma. Of those, 33 had transformed lymphoma and were treated with lenalidomide. These patients ranged in age from 42 to 84. More than half had stage IV disease, where the lymphoma has spread to multiple sites or organs. All patients had been treated with chemotherapy and some with stem cell transplant to curtail the cancer. The median number of previous treatments was four and ranged up to 12.
Patients took lenalidomide pills (25 mg) daily for 21 days. For seven days, no medication was given. The medication continued until signs of cancer progression. Overall, 45 percent of patients responded positively to the therapy, but results varied by the particular type of transformed lymphoma.
For transformed follicular lymphoma, the most common form of the illness, 13 of the 23 patients (57 percent) in this subgroup responded positively to lenalidomide. Ten patients with other types of transformed lymphoma did not respond. They included transformed chronic lymphocytic leukemia, small lymphocytic lymphoma and others.
Dr. Reeder notes that while the number of patients treated with lenalidomide was small, the results are promising because of the response rate, the length of the response, and the simplicity of treatment. In patients who responded, the positive effect of lenalidomide was seen for a median of nearly 13 months. Compared to chemotherapy drugs, lenalidomide is easy to administer and is well tolerated. "Its appeal is that it's not toxic to the patient," he says. Side effects were considered mild and included low white blood cell counts.
Lenalidomide is approved by the U.S. Food and Drug Administration to treat multiple myeloma and certain types of myelodysplastic syndrome. Mayo Clinic researchers and others have been studying its potential as a lymphoma treatment for about two years. Further studies are needed to confirm its role in treating patients with transformed lymphoma.