CAR-iNKT cells as a novel immunotherapy for B cells malignancies

Anti-CD19 chimeric antigen receptor T cell (CAR19-T) immunotherapy has shown curative potential in B cell malignancies. However, clinical remissions in relapsed/refractory CD19+ lymphomas and lymphoproliferative disorders are often short-lived, with therapeutic benefit for less than half of patients, highlighting the need for more effective CAR-based strategies. iNKT cells are rare but powerful immunoregulatory and cytotoxic T lymphocytes, playing a pivotal anti-tumour role. They are restricted by CD1d, a non-polymorphic, glycolipid-presenting HLA I-like molecule, expressed on malignant CD19+ B cells in mantle cell lymphoma (MCL) and marginal zone lymphoma (MZL) cells, while in up to 50% of patients with chronic lymphocytic leukaemia (CLL) CD1d expression is very low or negative. I tested the hypotheses that a) bi-specific CAR19-iNKT cells, targeting simultaneously CD19 and CD1d, via the CD19-specific CAR and their natural invariant TCR respectively, would be more effective than CAR19-T cells against CD19+CD1d+ B cell malignancies and b) transcriptional enhancement of CD1d expression would increase the CAR19-iNKT cytotoxic effect, including against CLL cells. I established and optimized a novel, highly efficient protocol for manufacturing clinical scale CAR19-iNKT cells. In vitro validation demonstrated that CAR19-iNKT cells are CD19-specific, retain their natural CD1d-restricted reactivity and exert additive dual-specific cytotoxicity against CD1d+CD19+ targets. Compared to same-donor CAR19-T, CAR19-iNKT cells display a significantly higher expandability and proliferative potential, they are equally or more effective in killing CD19+CD1d+ lymphoid cell lines and consistently more effective against primary MCL, MZL and CLL cells. Notably, I found that in CD1dlow/– primary CLL cells, surface CD1d expression can be restored by clinically relevant concentrations of all-trans retinoic acid (ATRA) and, in line with my hypothesis, CAR19-iNKT but not CAR19T cells displayed higher cytotoxic activity against ATRA-treated CLL cells. Finally, in an NSG xenograft model of lymphoma, CAR19-iNKT cell immunotherapy led to a significantly improved overall survival, with earlier, more profound and sustained complete responses, which resulted in a significantly improved tumour-free survival as well as eradication of CNS lymphoma. I conclude that CAR19-iNKT are more effective than CAR19-T cells against CD1d+CD19+ B cell malignancies in vitro and in vivo. This, together with the previously demonstrated ability of third donor-derived iNKT cells to protect from acute Graft-versus-Host Disease (aGVHD), raise the prospect of developing a more effective ‘off-the-shelf’ CAR19-iNKT immunotherapy for lymphomas. Furthermore, the finding that ATRA-mediated restoration of CD1d expression enhances the anti-lymphoma effect of CAR19-iNKT immunotherapy against CD1d low/negative tumour cells in vitro suggests that CAR-iNKT cells, in combination with transcriptional/epigenetic modulation of CD1d, may represent a highly efficient platform for CAR-based immunotherapy also for other CD1d-negative disorders.Open Acces

New drugs in the treatment of chronic myeloid leukaemia

The introduction of the BCR-ABL kinase inhibitor, imatinib mesylate (Gleevec®, Novartis) led to significant changes in the treatment of chronic myeloid leukaemia (CML) patients. However, despite the impressive percentage of responding patients, some CML cases, particularly those in advanced phases of the disease, show primary resistance or relapse after the initial response. The second-generation BCR-ABL inhibitors nilotinib (Tasigna®, Novartis) and dasatinib (Sprycel®, Bristol-Myers Squibb) have shown significant activity in clinical trials in patients who failed imatinib therapy, but these agents are still incapable of inhibiting the T315I mutant of Bcr-Abl and present partial activity in advanced phases of CML. The acquired biological notions of the mechanisms of tyrosine kinase inhibitor (TKI) resistance has led to the development of new compounds, some of which have shown encouraging preliminary results in clinical trials, even against T315I mutants. In this paper we discuss the new emerging therapies which may overcome TKI resistance in CML patients. A introdução do inibidor de tirosino quinase BCR-ABL mesilato de imatinibe (Glivec®, Novartis) levou a significantes mudanças no tratamento da LMC. Entretanto, a despeito de impressionante porcentagem de pacientes que respondem, alguns casos de LMC, particularmente em fases avançadas da doença mostram resistência primaria ou recidivas após terapêutica inicial. Inibidores de tirosino quinases de segunda geração como o nilotinibe (Tasigna®, Novartis) e o dasatinibe (Sprycel®, Bristol Myers Squibb) têm mostrado significante atividade nos estudos clínicos em paciente onde o imatinibe falhou. Porém, estes agentes não são capazes de inibir a mutação T315I do Bcr-Abl e apresentam atividade parcial em fases avançadas da LMC. As noções biológicas adquiridas sobre os mecanismos de resistência aos inibidores de TK levaram ao desenvolvimento de novos compostos alguns dos quais têm resultados preliminares encorajadores incluindo a mutação T315I. Neste trabalho nós discutimos os novos agentes emergentes e qual o potencial poderão atingir para ultrapassar a resistência aos inibidores de TK em pacientes com LMC

New drugs in the treatment of chronic myeloid leukaemia Novas drogas no tratamento da leucemia mielóide crônica

The introduction of the BCR-ABL kinase inhibitor, imatinib mesylate (Gleevec®, Novartis) led to significant changes in the treatment of chronic myeloid leukaemia (CML) patients. However, despite the impressive percentage of responding patients, some CML cases, particularly those in advanced phases of the disease, show primary resistance or relapse after the initial response. The second-generation BCR-ABL inhibitors nilotinib (Tasigna®, Novartis) and dasatinib (Sprycel®, Bristol-Myers Squibb) have shown significant activity in clinical trials in patients who failed imatinib therapy, but these agents are still incapable of inhibiting the T315I mutant of Bcr-Abl and present partial activity in advanced phases of CML. The acquired biological notions of the mechanisms of tyrosine kinase inhibitor (TKI) resistance has led to the development of new compounds, some of which have shown encouraging preliminary results in clinical trials, even against T315I mutants. In this paper we discuss the new emerging therapies which may overcome TKI resistance in CML patients.<br>A introdução do inibidor de tirosino quinase BCR-ABL mesilato de imatinibe (Glivec®, Novartis) levou a significantes mudanças no tratamento da LMC. Entretanto, a despeito de impressionante porcentagem de pacientes que respondem, alguns casos de LMC, particularmente em fases avançadas da doença mostram resistência primaria ou recidivas após terapêutica inicial. Inibidores de tirosino quinases de segunda geração como o nilotinibe (Tasigna®, Novartis) e o dasatinibe (Sprycel®, Bristol Myers Squibb) têm mostrado significante atividade nos estudos clínicos em paciente onde o imatinibe falhou. Porém, estes agentes não são capazes de inibir a mutação T315I do Bcr-Abl e apresentam atividade parcial em fases avançadas da LMC. As noções biológicas adquiridas sobre os mecanismos de resistência aos inibidores de TK levaram ao desenvolvimento de novos compostos alguns dos quais têm resultados preliminares encorajadores incluindo a mutação T315I. Neste trabalho nós discutimos os novos agentes emergentes e qual o potencial poderão atingir para ultrapassar a resistência aos inibidores de TK em pacientes com LMC

Overexpression of the fibroblast growth factor receptor 2-IIIc in Kaposi's sarcoma

Kaposi's sarcoma (KS) is a neoplastic disorder characterized by a highly vascularized lesion with bundles of spindle-shaped cells, pathognomonic of the disease, infiltrated by mononuclear inflammatory and plasma cells. The KS lesion presents as a patch/plaque, which eventually develops into a nodular tumor. Thus far, the mechanisms involved in the etiopathogenesis of KS are not completely understood. Kaposi's Sarcoma-associated Herpesvirus (KSHV) infection is present in all KS cases. However, KSHV is not sufficient for the development of the disease and other factors are certainly involved. Alterations in the expression of cytokines, growth factors and relative receptors have been analyzed over the years. To evaluate the involvement of FGFR2 in the development and progression of KS, we assayed by immunohistochemistry and quantitative real-time PCR (Q-RT-PCR) the expression of FGFR2-IIIb and FGFR2-IIIc in biopsies of KS lesions compared to normal skin. Further studies are needed to analyze whether FGFR2-IIIc up-regulation varies in the history of the disease, and whether these variations might correlate with the clinical status of the disorder. In any case, our survey provides new elements to better understand the complex interplay between viral infection and host response in the development of KS