BUFFALO, NY--Adding a chimeric anti-CD20 antibody to standard CHOP chemotherapy appears to produce a synergistic therapeutic effect in low-grade B-cell lymphomas. Patients on the regimen have achieved complete remissions and disappearance of the bcl-2 translocation, principal investigator Myron Czuczman, of the Roswell Park Cancer Institute, said at the annual Chemotherapy Foundation symposium.
Preliminary results of an ongoing pilot phase II trial show a 100% response rate in 16 evaluable patients (11 complete responses and 5 partial responses), with all responses ongoing at 5 to 18 months. Moreover, of the four patients whose bcl-2 status was known prior to therapy, all became bcl-2 negative by completion of therapy.
The antibody (IDEC-C2B8, from IDEC Pharmaceuticals Corporation, San Diego) targets the CD20 antigen, which is expressed on the surface of mature B cells and on B-cell tumors, but not on B-cell precursors or on plasma cells.
IDEC-C2B8 binds to its target antigen and recruits host defenses to attack and kill both malignant and normal B cells. After treatment, the normal B cells regenerate from stems cells within months, without damage to the marrow.
In the ongoing trial, patients are given IDEC-C2B8 at a dose of 375 mg/m2 on weeks 1 (two doses), 7, 13, 20, and 21, for a total of six doses. CHOP (cyclophosphamide, doxorubicin(Drug information on doxorubicin), vincristine, and prednisone(Drug information on prednisone)) is given on weeks 2, 5, 8, 11, 14, and 17, for a total of six cycles.
Forty patients have been enrolled in the study to date, and data were reported for 27 of these patients, 16 of whom have completed all scheduled therapy.
The trial is being conducted at Roswell Park Cancer Institute, Northwestern University, the University of Alabama at Birmingham, and the Sharp Health Care and Sidney Kimmel Cancer Center in San Diego.