CHEMOTHERAPY ACCORDING TO THE R-mNHL-BFM-90 PROTOCOL IN COMBINATION WITH LENALIDOMIDE AS THE FIRST LINE THERAPY IN PATIENTS WITH MUM1-POSITIVE DIFFUSIVE LARGE B-CELL LYMPHOMA AND FOLLICULAR LYMPHOMA GRADE 3B

Introduction. Diffuse large B-cell lymphoma of postgerminal origin (ABC-DLBCL) and follicular lymphoma grade 3B (FL3B) are characterised by an aggressive course and resistance to chemotherapy (CT). Both diseases are characterised by the activation of genes of the post-terminal stage of B-cell differentiation and high expression of the MUM1 transcriptional protein. Lenalidomide in combination with R-CHOP improved the results of treatment in patients with ABC-DLBCL; however, about 40 % of them remain resistant to the therapy. Aim. The aim of the study was to evaluate the efficacy and toxicity of the R-mNHL-BFM-90 protocol with lenalidomide (R2-mNHL-BFM-90), as well as to analyse possible causes of CT resistance in patients with ABC-DLBCL and FL3B. Patients and methods. Over the period from October 2016 to December 2018, 8 patients with MUM1-positive DLBCL and FL3B were included in the research. All patients underwent a cytogenetic study of tumour samples. A mutational status of the TP53 gene was determined by Sanger sequencing. Results. Patients received combination chemotherapy according to the R2-mNHL-BFM-90 protocol with lenalidomide at a dose of 25 mg/day, from the 1st to the 10th day of each course. Autologous hematopoietic stem cell transplantation was performed as a consolidation in three patients. After the end of the chemotherapy, a complete remission of the disease was achieved in all patients. Relapse developed in 1 patient with a mutation in the TP53 gene. With a median follow-up period of 11 months (1-23), event-free survival was 87 %. Conclusions. The R2-mNHL-BFM-90 protocol has demonstrated a high efficacy and acceptable toxicity in patients with ABC-DLBCL and FL3B. The presence of a mutation in the TP53 gene is established to be an extremely unfavourable prognostic factor even provided intensive treatment protocols, thus requiring the development of alternative approaches to the management of such patients.