Search

Daratumumab is a human anti-CD38 monoclonal antibody used in the treatment of refractory and relapsed multiple myeloma. We investigated the efficacy and safety of daratumumab therapy in a real-world setting. Ninety-nine Hungarian patients were included; 48 received monotherapy, while lenalidomide and bortezomib combinations were administered in 29 and 19 cases, respectively. Overall response rate was assessable in 88 patients, with 12 complete, 10 very good partial, 34 partial, and seven minor responses. At a median duration of follow-up of 18.6 months, median progression-free survival (PFS) among all patients was 17.0 months. These values were inferior in the bortezomib combination and monotherapy groups. Patients with early-stage disease (ISS1) had better survival results than those with stage 2 or 3 myeloma (p = 0.009). Heavily pretreated patients had inferior PFS compared to those with 1-3 therapies (p = 0.035). Patients with impaired renal function had PFS results comparable with those having no kidney involvement. There were 10 fatal infections, and the most frequent adverse events were mild infusion-associated reactions and hematologic toxicities. Our results confirm that daratumumab is an effective treatment option for relapsed/refractory MM with an acceptable safety profile in patients with normal and impaired renal function. [ABSTRACT FROM AUTHOR]

CD49d and CXCR4 are key determinants of interactions between chronic lymphocytic leukemia (CLL) tumor cells and their microenvironment. In this study, we investigated the effect of CD49d and CXCR4 expressions on survival of CLL cells. Primary CLL cells were cultured with CD49d ligand, VCAM-1, or bone marrow stromal cells (BMSCs); then, apoptosis and immunophenotype analyses were performed. VCAM-1 treatment could not induce direct apoptosis protection or immunophenotype change on the CD49d-expressing CLL cells, but resulted in actin reorganization. The BMSC-induced apoptosis protection was independent from the presence of CD49d expression of CLL cells, but showed an inverse correlation with their CXCR4 expression level. We suppose that CD49d contributes to enhanced survival of leukemic cells by mediating migration to the protective microenvironment, not by direct prevention of apoptosis. Moreover, CLL cells with low CXCR4 expression represent a subpopulation that is more dependent on the microenvironmental stimuli for survival, and show increased "death by neglect" when separated from the supportive niche. [ABSTRACT FROM AUTHOR]

The prolonged life span of chronic lymphocytic leukemia (CLL) cells in vivo is assumed to depend on the surrounding microenvironment since this biologic feature is lost in vitro. We studied here the molecular interactions between CLL cells and their surrounding stroma to identify factors that help CLL cells to resist apoptosis. Sorted CLL cells from 21 patients were cultured in vitro on allogenous, normal bone marrow stromal cells (BMSCs) in the presence/absence of CD40 ligand or in culture medium alone. Surface and mRNA expression of interaction molecules, cytokine production, and apoptosis rate was measured by flow cytometric, real-time PCR and standard immunologic assays. The interaction between CLL cells and BMSCs rescued CLL cells from apoptosis. BMSCs co-cultured with CLL cells showed a strong increase in IL-8 and IL-6 secretion and up-regulated the expression of ICAM-1 and CD40 mRNA. The mRNA expression of CXCL12 and VCAM1 remained unchanged. In turn, CLL cells in interaction with BMSCs significantly up-regulated the expression of CD18 and CD49d that are ligands for the critical adhesion molecules on BMSCs. As a validation of the in vitro data, we found a significant higher expression of CD49d on CLL cells in bone marrow aspirates compared to peripheral blood CLL cells in patient samples. Up-regulation of adhesion molecules and their ligands in CLL-BMSCs interaction along with the increased cytokine production of BMSCs indicate a strong effect of CLL cells on BMSCs in favor of their apoptosis resistance. [ABSTRACT FROM AUTHOR]