Adding a second monoclonal antibody drug to chemotherapy looks promising for treatment of diffuse large B-cell lymphoma, according to Mayo Clinic researchers working with the North Central Cancer Treatment Group (NCCTG) . Results of this interim analysis were released May 15 as part of the 44th Annual Meeting of the American Society of Clinical Oncology.
Researchers found that 95 percent of patients responded to treatment that included the drug epratuzumab with the standard "R-CHOP" therapy. R-CHOP combines three chemotherapy drugs (cyclophosphamide, doxorubicin and vincristine) with the steroid drug prednisone and rituximab, a monoclonal antibody. Final results will be reported next year.
Diffuse large B-cell lymphoma is one of the most common and aggressive forms of non-Hodgkin lymphoma (NHL), a cancer of the white blood cells known as B-lymphocytes.
In 78 patients, researchers found:
Researchers also were able to look at the primary endpoint of the study -- disease-free survival at 12 months -- in 34 patients. Eighty five percent of that group, 29 patients, had no signs of lymphoma.
"These results are good, but whether it will turn out to be better than standard therapy is still unknown," says the study's lead author, Ivana Micallef, M.D., a Mayo Clinic hematologist.
Epratuzumab is much like rituximab because both are monoclonal antibodies, and both attach to proteins commonly found on the surface of B-cells -- CD20 for rituximab and CD22 for epratuzumab. Both also are used to treat certain autoimmune disorders, such as rheumatoid arthritis and lupus. "In autoimmune disease, you are trying to stop the B-cells from making the antibodies that cause inflammation, but in cancer, these B-cells are malignant," says Dr. Micallef.
This is the first large study to combine epratuzumab with chemotherapy, in this case R-CHOP.
The rate of toxic side effects among enrolled patients was the same as seen in R-CHOP use, investigators say. "Overall, the combination was well tolerated," says Dr. Micallef. Patients may experience low blood counts, fatigue or infections.
As promising as these results look, researchers will not know if this new treatment provides superior results to R-CHOP unless the two regimens are compared with each other, she says.
Other NCCTG collaborators included Matthew Maurer, Paul Kurtin, M.D., and Thomas Witzig, M.D., all of Mayo Clinic; Daniel Nikcevich, M.D., St. Mary's Duluth Clinic, Duluth, Minn.; Michael Cannon and Dennis Moore, M.D., both of Cancer Center of Kansas PA, Wichita.
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