Combined Immuno-Chemotherapy (R-CHOP) Results in Significantly Superior Response Rates and Time to Treatment Failure in First Line Treatment of Patients with Lymphomplasmocytoid/ic Immunocytoma (LP-IC) - Results of a Prospective Randomized Trial of the German Low Grade Lymphoma Study Group (GLSG).

Lymphomplasmocytoid/ic immunocytoma (LP-IC), including Waldenstrom’s macro-globulinemia and lymphoplasmacytoid lymphoma according to the Kiel classification (the latter one subsummed as a variant of B-CLL in the WHO classification), is an indolent lymphoma, which is incurable by conventional chemotherapy in the advanced stage of disease. The anti-CD20 antibody Rituximab has shown remarkable activity in indolent lymphomas, in particular when combined with chemotherapy. Based on these results the GLSG investigated the efficacy of a combined immuno-chemotherapy (R-CHOP: Rituximab 375 mg/m² d0-1; cyclophosphamide 750 mg/m² d1; doxorubicine 50 mg/m² d1; vincristine 1.4 mg/m² d1; prednisone 100 mg/m² d1-5) versus CHOP alone as first line treatment of LP-IC in a multicenter prospective randomized phase III trial. Of 72 patients 71 % were classified as lymphoplasmacytic lymphoma, 29 % as lymphoplasmocytoid subtype by central pathology review. The median age was 61.5 years (60 years for R-CHOP and 62 years in the CHOP arm); 24% of the patients had an IPI score >2. The overall response (OR) rate was significantly improved by combining Rituximab with CHOP compared to CHOP alone with an OR of 94% (11% CR, 83% PR) for R-CHOP and an OR of 69% (3% CR, 67% PR) for CHOP (p=0.012). Furthermore, patients treated with R-CHOP showed a significantly prolonged time to treatment failure (TTF) with an estimated median TTF of 22 month in the CHOP arm, whereas the median was not reached in the immunochemotherapy arm after a maximum follow up of nearly 4 years (p=0.0057). There was no major difference of the toxicity in both treatment groups. In summary, these data indicate a beneficial effect of combined immunochemotherapy (R-CHOP) as compared to CHOP alone with regards to initial cytoreduction as well as TTF in patients with LP-IC in a prospective randomized trial, establishing R-CHOP as an highly attractive regimen for first line treatment of this distinct lymphoma subtype.