Treatment of patients with low-grade B-cell lymphoma with the combination of chimeric anti-CD20 monoclonal antibody and CHOP chemotherapy

Purpose: To determine the safety and efficacy of the combination of the chi meric anti-CD20 antibody Rituxan (Rituximab, IDEC-C2B8; IDEC Pharmaceutical s Corporation, San Diego, CA), and cyclophosphamide, doxorubicin, vincristi ne, and prednisone (CHOP) chemotherapy. Patients and Methods: Forty patients with low-grade or follicular B-cell no n-Hodgkin's lymphoma received six infusions of Rituxan (375 mg/m(2) per dos e) in combination with six doses of CHOP chemotherapy. Results: The overall response rate was 95% (38 of 40 patients). Twenty-two patients experienced a complete response (55%), 16 patients had a partial r esponse (40%), and two patients, who received no treatment, were classified as nonresponders. Medians for duration of response and time to progression had not been reached after a median observation time of 29 + months, Twent y-eight of 38 assessable patients (74%) continued in remission during this median follow-vp period. The most frequent adverse events attributable to C HOP were alopecia (38 patients), neutropenia (31 patients), and fever (23 p atients). The most frequent events attributed to Rituxan were fever and chi lls, observed primarily with the first infusion. No quantifiable immune res ponse to the chimeric antibody was detected. In a subset of 18 patients, th e bcl-2 [t(14;18)] translocation was positive in eight patients; seven of t hese patients herd complete remissions and converted to polymerase chain re action (PCR) negativity by completion of therapy. Conclusion: This is the first report demonstrating the safety and efficacy of Rituxan anti-CD20 chimeric antibody in combination with standard-dose sy stemic chemotherapy in the treatment of indolent B-cell lymphoma. The clini cal responses suggest an additive therapeutic benefit for the combination w ith no significant added toxicity. The conversion of bcl-2 from positive to negative by PCR in blood and/or marrow suggests possible clearing of minim al residual disease nat previously demonstrated by CHOP chemotherapy alone. J Clin Oncol 17:268-216, (C) 1999 by American Society of Clinical Oncology.