CTNI-83. MATRIX REGIMEN FOR NEWLY DIAGNOSED PRIMARY CNS DIFFUSE B-CELL LYMPHOMA

Abstract

Abstract We report our experience treating 25 patients with newly diagnosed primary CNS diffuse B-cell lymphoma with the MATRix regimen as reported by Ferreri, et al in 2016. The median age was 66 y (range 30-85); 12 patients were men and 13 were women. Twenty-three had cerebral mass lesions, 1 had a paraspinal mass, and 1 leptomeningeal disease. Treatment consisted of 4 cycles of rituximab 375 mg/sq m (Days 1, 6); methotrexate 3.5 g/sq m (Day 2); cytarabine 2 g/sq m every 12 h (Days 3, 4); and thiotepa 30 mg/sq m (Day 5). Patients without disease progression received carmustine 400 mg/sq m and thiotepa 5 mg/kg followed by autologous bone marrow transplantation. Four patients were switched to MATRix after 6 cycles of methotrexate and rituximab and received only 2 initial cycles including cytarabine and thiotepa. Overall, 18 patients completed initial chemotherapy. Sixteen of these 18 went on to transplantation; one patient had had early disease progression, and in one no stem cells could be collected. Five patients (median 73 y; range 64-85 y) died early after 1-2 cycles. The causes of early death were neutropenic fever, septic thrombophlebitis, and cardiac arrest. One of the 16 patients who completed the entire regimen including transplantation died of fungal pneumonia and the other 15 experienced no serious acute toxicity. One patient had late disease progression and 2 developed symptomatic leukoencephalopathy. Seventeen of the 25 patients remain alive. Median TTP for the cohort is 605 days, and OS 738 days. These preliminary data suggest that the MATRix regimen in safe and highly effective in the newly diagnosed setting. However, the high incidence of early death in patients over 65 y shows that the regimen is too toxic for older individuals.