Effect of IGHV Gene Mutation Status and BCR Structure Stereotypy on Effectiveness of BR Regimen in First-Line Therapy of Chronic Lymphocytic Leukemia

Background & Aims. The IGHV gene mutation status is a constant biological feature of tumor cells in chronic lymphocytic leukemia (CLL). This parameter is an important predictor of the efficacy of immunochemotherapy. It was included into the CLL international prognostic index CLL-IPI developed recently. The aim is to evaluate the prognostic significance of the BR regimen in patients with different variants of the B-cell receptor (BCR) structure. Methods. The study examined immediate and delayed treatment outcomes for 183 CLL patients included in a Russian, prospective, observational BEN-001 trial (NCT02110394). The median age was 61 years (range: 35–79); 53/179 (29.6 %) patients were older than 65; and 14/179 (7.8 %) patients were older than 75. Prevalence of males (110/179, 61.5 %) in the male/female ratio (1.6:1.0) was observed. Most patients had advanced disease: Binet B 116/173 (67 %) or Binet C 38/173 (22 %). The patients received the first-line therapy according to the BR regimen at standard doses in 36 hematological institutions in the Russian Federation over the period from 2012 until 2015. The genome DNA isolated from mononuclear leukocytes in the peripheral blood was used to assess the mutation status of the IGHV-genes. Results. The study demonstrated that unmutated CLL (≥ 98 % of homology to germline gene) is associated with worsening of the event-free and overall survival rates most of all; at that, the complete remission rate and the MRD-free survival rate were the same. Conclusion. It is reasonable to analyze the IGHV mutation status in all patients prescribed with the BR regimen as the first-line therapy.