How Much Rituximab Do We Need: A Multicenter, Randomized Trial Comparing 1, 3 or 6 Infusions of Rituximab Added to 6 Cycles of CHOP Chemotherapy in Untreated Patients with Advanced Follicular Non-Hodgkins Lymphoma (HD2000-Trial).

Purpose: The combination of chemotherapy with the chimeric anti-CD20 antibody Rituximab has been reported to be highly active in the treatment of follicular lymphoma. The frequency and dosage of rituximab required to induce the maximum effect in follicular NHL is not defined. To evaluate how often rituximab should be added to standard chemotherapy to achieve maximum remission rates, we have initiated a prospective randomized multicenter phase II study.

Methods: Patients (pts) with stage III/IV CD20 positive follicular NHL who were chemotherapy naïve were randomly assigned to receive 6 courses of a standard CHOP-21 chemotherapy, accompanied by rituximab 375 mg/m2 at day 0 only with the first CHOP course (arm A), with the first 3 CHOP courses (arm B) or with all 6 CHOP courses (Arm C). The major endpoint was the rate of molecular remission in bone marrow and peripheral blood in initially t(14;18)-positive pts, assessed by PCR. Other endpoints of the study were overall and complete response rates, toxicity rate and time to progression.

Results: Since September 2000, 104 pts with a median age of 57 years (range 30–80) were recruited. 33 pts were randomized to arm A, 35 to arm B and 36 to arm C. So far 69 pts have been documented completely after all 6 cycles and are evaluable for side effects. All three treatment arms were well tolerated. The incidence of adverse events and Grade 4 toxicity was similar in all groups. One treatment related death was observed 2 months after completion of therapy due to hepatitis B. The overall response rate (ORR) of the whole group, which was evaluable in 69 pts so far, was 90 % (62 of 69 pts), with 20 complete and 42 partial remissions.

Conclusion: This multicenter, randomized, phase II trial addresses for the first time the optimal frequency and dosage of rituximab infusions in the combined immuno-chemotherapy. In the first interim analysis of the ongoing trial, similar hematologic, gastrointestinal and infectious toxicity was observed in all treatment arms.