ACTR-16. MATRix REGIMEN FOR NEWLY DIAGNOSED PRIMARY DIFFUSE B-CELL LYMPHOMA OF THE CENTRAL NERVOUS SYSTEM: PRELIMINARY RESULTS

Abstract

Abstract We report our preliminary experience treating 9 patients with newly diagnosed primary diffuse B-cell lymphoma of the central nervous system with the MATRix regimen as reported by Ferreri, et al in 2016. The median age was 63 y; 5 patients were men and 4 were women. Seven had cerebral mass lesions, 1 a paraspinal mass, and 1 leptomeningeal disease. Five patients underwent biopsy; 2 imaging total resection; 1 subtotal resection; and in 1 the extent of resection was indeterminate. Treatment consisted of 4 cycles of rituximab 375 mg/sq m (Days 1, 6); methotrexate 4 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. Two patients were switched to MATRix after 6 cycles of methotrexate and rituximab and received 2 additional cycles that included cytarabine and thiotepa. Overall, 7 patients completed initial chemotherapy, with 5 complete responses and 2 partial responses. Six of these 7 went on to transplantation and remain alive without disease progression after a median follow-up of 470 days. One patient with initial PR progressed and did not proceed to transplantation. Two patients died after 1 cycle; they were both over 70 y (76 and 84) and succumbed to sepsis with neutropenic fever. No serious acute toxicity occurred in the 6 patients who completed the entire regimen including transplantation; 1 patient has experienced symptomatic leukoencephalopathy. Overall progression free survival was 394 days. These preliminary data suggest that the MATRix regimen in safe and highly effective in the newly diagnosed setting. However, the high early mortality in patients over 70 years in this group suggests that the regimen may be too toxic for very elderly individuals.