(R)-GEMOX chemotherapy for unfit patients with refractory or recurrent primary central nervous system lymphoma: a LOC study

Recurrent primary central nervous system lymphomas (PCNSL) have a very poor prognosis. For young and fit patients, intensive chemotherapy followed by autologous stem cell transplantation could be proposed at relapse. In the other cases (unfit or elderly patients), therapeutic options are limited with no consensual regimen. The poly-chemotherapy by (R)-GEMOX is associated with anti-tumor activity in systemic lymphomas and a favorable toxicity profile. Our objective was to evaluate the activity and tolerance of (R)-GEMOX in PCNSL patients enrolled in the French nation-wide LOC cohort. We retrospectively analyzed all refractory or recurrent patients included in the LOC network who benefited from (R)-GEMOX (rituximab 375mg/m(2), gemcitabine 1000mg/m(2), and oxaliplatine 100mg/m(2)). Administration, tolerance, and efficacy data were analyzed. Thirteen patients, treated in five different institutions, benefited from the (R)-GEMOX regimen from February 2013 to August 2017. At the initiation of (R)-GEMOX, median age was 71.4years old (range, 49.5-82.5) and median Karnofsky performance status (KPS) was 60 (range, 40-80). Seven patients were in second line of treatment whereas the six others were in third line or over. All patients had received methotrexate-based polychemotherapy as first-line treatment except one. Overall response rate was 38% with two complete responses and three partial responses. Median progression-free survival was 3.2months (95%CI: 0.2-6.2), and median overall survival was 8.2months (95%CI: 0.6-15.8). Toxicity was mainly hematological including grade neutropenia (38%), lymphopenia (23%), and thrombopenia (23%). Older age (p=0.046) and low KPS (p=0.054) tended to be associated with a worse prognosis. (R)-GEMOX is associated with substantial response rate and favorable toxicity profile in unfit patients with recurrent PCNSL. (R)-GEMOX could be considered to be an additional option in patients with recurrent/refractory PCNSL.