High-dose methotrexate with R-CHOP therapy for the treatment of patients with primary central nervous system lymphoma

We describe MR-CHOP therapy, a novel treatment regimen consisting of high-dose methotrexate and R-CHOP that provides systemic anti-tumor activity with penetration of the blood–brain barrier in patients with newly diagnosed primary central nervous system lymphoma. The MR-CHOP regimen was administered with 2 g/m² of methotrexate and 375 mg/m² of rituximab on day 1, 750 mg/m² of cyclophosphamide on day 3, 50 mg/m² of doxorubicin on day 3, 1.4 mg/m² of vincristine on day 3 and 100 mg of prednisolone on days 1–5 in this pilot study of seven patients. Six cycles of MR-CHOP therapy were administered every 3 weeks, followed by high-dose chemotherapy with stem cell rescue in young patients, or an additional two cycles of 4 g/m² methotrexate and rituximab in older patients. The overall response rate was 100%, with 85.7% complete remission (CR). One patient showed partial response, relapsed and subsequently died. Another relapsed following CR, and was rescued by further salvage therapy. The others survive without relapse at a median observation period of 24 months. Hematological toxicity included grade 4 leukocytopenia in 4/7 and neutropenia in 5/7, which were transient and tolerated well. Non-hematological toxicities were tolerated well. The efficacy of this novel regimen as remission induction therapy was found to be promising in this pilot study, although the number of patients was small and follow-up short.