Anti-CD19 Monoclonal antibody, clone 2E4 [eFluor® 450]

Background A high multiple sclerosis activity while on alemtuzumab is rather uncommon compared to moderate-efficacy drugs. The purpose of this case report is to present a case of a 37-year-old female patient with bronchial asthma and no other medical history, whose disease activity required switching from dimethyl fumarate to fingolimod, then to alemtuzumab and finally to ocrelizumab. Case presentation In our patient, two severe attacks were observed and treated after administration of the first pulse of alemtuzumab. After six months of therapy, patient's immunological profile showed the expected decrease in CD4+ and CD8+ T-cells and, markedly increased values of CD19+ B-cells. Surprisingly memory B-cells, which typically repopulate very slowly following alemtuzumab treatment, were above baseline levels. Regular administration of ocrelizumab based on a standardised scheme, after the alemtuzumab therapy failure, resulted in the stabilisation of the patient's condition both clinically and radiologically. Conclusion Thus, when the alemtuzumab treatment is unsuccessful, the authors recommend testing T- and B-cell levels and proceeding with an early switch to ocrelizumab if high B-cell counts are found.

Purpose: The murine Lym-1 mAb targets a discontinuous epitope (Lym-1 epitope) on several subtypes of HLA-DR, which is upregulated in a majority of human B-cell lymphomas and leukemias. Unlike CD19, the Lym-1 epitope does not downregulate upon crosslinking, which may provide an advantage as a target for CAR T-cell therapy. Lym-1 CAR T cells with a conventional 4-1BB and CD3 zeta (BB3z) signaling domain exhibited impaired ex vivo expansion. This study aimed to identify the underlying mechanisms and develop strategies to overcome this effect. Experimental Design: A functional humanized Lym-1 antibody (huLym-1-B) was identified and its scFv form was used for CAR design. To overcome observed impaired expansion in vitro, a huLym-1-B CAR using DAP10 and DAP12 (DAP) signaling domains was evaluated for ex vivo expansion and in vivo function. Results: Impaired expansion in huLym-1-B-BB3z CAR T cells was shown to be due to ligand-dependent suboptimal CAR signaling caused by interaction of the CAR binding domain and the surface of human T cells. Using the novel DAP signaling domain construct, the effects of suboptimal CAR signaling were overcome to produce huLym-1-B CAR T cells with improved expansion ex vivo and function in vivo. In addition, the Lym-1 epitope does not significantly downregulate in response to huLym-1-B-DAP CAR T cells both ex vivo and in vivo. Conclusions: DAP intracellular domains can serve as signaling motifs for CAR, and this new construct enables nonimpaired production of huLym-1-B CAR T cells with potent in vivo antitumor efficacy.