Rituximab, gemcitabine, cisplatin, and methylprednisolone (R-GEM-P) in treatment of relapsed diffuse large B-cell lymphoma (DLBCL).

Abstract

e19543 Background: Patients with DLBCL who relapse after 1st line therapy have poor prognosis. Although there is limited evidence for benefit of rechallenging patients with rituximab, this is considered justified by minimal toxicity and potential outcome improvement. GEM-P+/-R is an accepted salvage regimen, with merits of outpatient delivery and mainly non-overlapping toxicity with 1stline therapy, but there are relatively few reports of its efficacy and tolerability. Methods: We performed a retrospective single centre analysis of all patients meeting the following criteria: age≥18, histologically proven DLBCL, ≥1 FDG-PET, treated between 2001-2011 with GEM-P+/-R (gemcitabine 1000mg/m2 D1, D8, D15, methylprednisolone 1000mg D1-5, cisplatin 100mg/m2 D15 every 28 days +/- rituximab 375mg/m2 D1 & D15) or GEM-CARBO+/-R (cisplatin substituted for carboplatin AUC5). Data were collected on patient and treatment characteristics, response evaluated by modified IWG 2007 criteria (FDG-PET +/- CT), survival, and toxicity (CTCAE v4.0). Results: We identified 74 patients with median age 56 (range 25-79) who received a median of 3 cycles (range 1-6) of either GEM-P (89%) or GEM-CARBO(11%), combined with rituximab in 69%. 41% had transformed indolent lymphoma. Overall response rate (ORR) was 49% (complete response (CR) 16%, partial response (PR) 32%). Among 40/74 patients evaluated with FDG-PET, metabolic ORR was 63% (mCR 23%, mPR 40%). Of 51/74 patients treated in 2ndline, ORR was 45%. Significantly higher ORR was observed in patients treated with R-chemotherapy (61% vs 22%, p=0.002), despite 88% having received prior rituximab. 17 patients proceeded to autologous transplant. With median follow up of 50.5 months, 3 yr overall survival in all patients from start of GEM-P was 39% and 3 yr progression free survival 19%. Predominant Grade≥3 toxicity was haematological; thrombocytopenia 69%, neutropenia 58%, anaemia 15% and febrile neutropenia 8%. Conclusions: R-GEM-P is an effective salvage regimen in DLBCL, with the convenience of outpatient delivery. Despite previous rituximab exposure, patients in our cohort benefited from the addition of rituximab, supporting current practice.