Combination Therapy with Rituximab and Temozolomide for Recurrent and Refractory Primary Central Nervous System Lymphoma

High-dose methotrexate-based chemotherapy has extended survival in patients with primary central nervous system lymphoma (PCNSL). However, although salvage treatment is necessary in recurrent and refractory PCNSL, this has not been standardized. We herein describe the efficacy of a combination of rituximab and temozolomide (TMZ) in two consecutive patients with recurrent and refractory PCNSL. Based on the immunohistochemical study, case 1 had a non-germinal center B-cell-like (non-GCB) subtype, was positive for bcl-2 and negative for O6-methylguanine-DNA methyltransferase (MGMT). Case 2 was GCB subtype, bcl-2-, and MGMT+. Because of the positive expression of MGMT, interferon-beta was additionally given in case 2. Complete responses and partial responses were obtained after the third and fourth cycles of combination therapy, respectively. This was maintained for 12 months, with acceptable toxicity. The combination of rituximab and TMZ was effective in tumors with different immunohistochemical profiles. This combination therapy warrants further study in a larger population.