[CAR-T cells: Lymphocytes that express a chimeric antigen receptor]. / CAR-T cells : lymphocytes exprimant un récepteur chimérique à l'antigène.

CAR-T cells are genetically modified human lymphocytes and gene therapy medicinal products. They are developed to treat cancers that express a membrane antigen targeted by the CAR. The FDA approved the two first-in-class medicinal products in 2017 and EMA in August 2018; both are autologous CAR-T cells targeting CD19 that is expressed at the surface of normal B-cells throughout their differentiation, and on B-cell lymphoid malignancies. Clinical efficacy was demonstrated for B-cell acute lymphoblastic leukemias, non-Hodgkin's lymphoma and chronic lymphocytic leukemia, although the marketing authorizations are less liberal in terms of indications. Manufacturing of these personalized treatments necessitates that a novel organization and supply chain be set in place, to ensure product preservation, patient safety and compliance with complex regulatory requirements. Side effects are commensurate with clinical efficacy and can be life-threatening: proper management imposes tight coordination between various specialists, particularly between hematologists and intensive care practitioners. High pricing for these treatments is part of a long-term trend for increasing costs of innovations in hematology and oncology; it questions the ability of healthcare systems to sustain their reimbursement.

Corrigendum: Disease status is a more reliable predictive factor than histology in lymphoma patients after reduced-intensity conditioning regimen and allo-SCT.

This corrects the article DOI: 10.1038/bmt.2012.225.

Highly favorable outcome in BRCA-mutated metastatic breast cancer patients receiving high-dose chemotherapy and autologous hematopoietic stem cell transplantation.

Breast cancer carrying BRCA mutation may be highly sensitive to DNA-damaging agents. We hypothesized a better outcome for BRCA-mutated (BRCA(mut)) metastatic breast cancer (MBC) patients receiving high-dose chemotherapy and autologous hematopoietic stem cell transplantation (HDC AHSCT) versus unaffected BRCA (BRCA wild type; (BRCA(wt))) or patients without documented BRCA mutation (BRCA untested (BRCA(ut))). All female patients treated for MBC with AHSCT at Institut Paoli-Calmettes between 2003 and 2012 were included. BRCA(mut) and BRCA(wt) patients were identified from our institutional genetic database. Overall survival (OS) was the primary end point. A total of 235 patients were included. In all, 15 patients were BRCA(mut), 62 BRCA(wt) and 149 BRCA(ut). In multivariate analyses, the BRCA(mut) status was an independent prognostic factor for OS (hazard ratio (HR): 3.08, 95% confidence interval (CI): 1.10-8.64, P=0.0326) and PFS (HR: 2.52, 95% CI :1.29-4.91, P=0.0069). In this large series of MBC receiving HDC AHSCT, we report a highly favorable survival outcome in the subset of patients with documented germline BRCA mutations.

[Conservation and destruction of autologous and allogeneic cryopreserved cellular products: recommendations from the SFGM-TC]. / Modalités de conservation et de destruction des produits cellulaires cryopréservés : recommandations de la SFGM-TC.

Thousands of autologous and at less extent allogeneic hematopoietic stem cells (HSC) bags are cryopreserved in France. The majority of autologous HSC grafts are used within a year after collection. However, many bags are still unused and cryopreserved for many years. In France and on a European scale, the ever-growing number of cryopreserved bags represents a real economic health concern. Indeed, the cost of storage is about 100€ per bag and per year. In addition, quality and therapeutic value of these long-term cryopreserved grafts needs to be evaluated. In the attempt to harmonize clinical practices between different French transplantation centers, the French Society of Bone Marrow Transplantation and Cell Therapies (SFGM-TC) set up its fourth annual series of workshops which brought together practitioners from its member centers across France. These workshops took place in September 2013 in Lille. In this article, we addressed the issue of the destruction of long-term cryopreserved grafts be them autologous or allogeneic and provide recommendations regarding their destruction.

Disease status is a more reliable predictive factor than histology in lymphoma patients after reduced-intensity conditioning regimen and allo-SCT.

We analyzed 113 patients with lymphoma who underwent allogeneic transplantation with reduced-intensity conditioning (allo-RIC) regimens at a single institution, from February 2001 through November 2009, searching for factors predictive of the outcome. At the time of transplantation, 60% of patients were in CR, 29% in PR and 11% had progressive or stable disease. At a median follow-up of 34 months (confidence interval (CI) 17-45), the 3-year OS and PFS were 59% (CI 48-68%) and 51% (CI 41-61%), respectively. The 100-day and 2-year nonrelapse mortalities (NRM) were 6% and 28% (CI 20-35%), respectively. Grade II-IV acute GVHD (aGVHD) incidence was 38%, and the global incidence of chronic GVHD was 33%. In univariate analysis, OS was influenced by disease status before allo-RIC; aGVHD negatively affected on survival. Similarly, PFS was influenced only by disease status. Histological subtype did not affect OS or PFS. We conclude that disease status at the time of transplantation significantly influences survival in patients receiving allo-RIC for lymphoma, whereas histological subtype does not. This reinforces the need to administer more effective debulking treatments to lymphoma patients, for optimal benefit of allogeneic immune recognition of minimal residual disease, independently from lymphoma histology.

Development of an enhanced B-specific lentiviral vector expressing BTK: a tool for gene therapy of XLA.

Further development of haematopoietic stem cell (HSC) gene therapy will depend on enhancement of gene transfer safety: ad hoc improvement of vector design relating to each particular disease is thus a crucial issue for HSC gene therapy. We modified a previously described lentiviral vector by adding the Emumar B-specific enhancer to a human CD19 promoter-derived sequence (Mol Ther 2004;10:45-56). We thus significantly improved the level of expression of the green fluorescent protein (GFP) reporter gene while retaining the specificity of expression in B-cell progeny of transduced human CD34+ progenitor cells obtained from cord blood or adult bone marrow. Indeed, GFP was strongly expressed from early medullary pro-B cells to splenic mature B cells whereas transgene expression remained low in transduced immature progenitors as in myeloid and T-lymphoid progeny retrieved from xenografted NOD/SCID/gammac(null) mice. Using this lentiviral vector, we further demonstrated the possibility to express a functional human BTK protein in long-term human CD34+ cell B-lymphoid progeny. This newly designed lentiviral vector fulfils one of the pre-requisites for the development of efficient and safe gene therapy for X-linked agammaglobulinaemia, the most common primary humoral immunodeficiency disorder.

CD34(+) progenitors are reproducibly recovered in thawed umbilical grafts, and positively influence haematopoietic reconstitution after transplantation.

Cord blood (CB) units are increasingly used for allogeneic transplantation. Cell dose, a major factor for CB selection, is evaluated before freezing by each CB bank, using various techniques. This may introduce variability and affect the prediction of cell recovery after thawing, or haematopoietic reconstitution. Forty-two children were transplanted at the same institution with unrelated CB units. All units were thawed and evaluated at the same cell therapy facility, using standard procedures. We investigated: (i) factors that affect cell loss after thawing, and (ii) the importance of CD34(+) cell doses. Prefreeze and post-thaw CD34(+) cell doses were statistically correlated, thus suggesting that variability in numeration techniques used by different CB banks does not compromise the biological and clinical value of these figures. CD34(+) cell recovery appeared to be correlated with the absolute number of CD34(+) cells per frozen bag. Infused CD34(+) is the cell dose that better correlates with platelet reconstitution delay; in addition, when using a quartile comparison, haematopoietic recovery appeared to be related with prefreeze and post-thaw CD34(+) cell doses. We conclude that enumeration of CD34(+) cells in CB units is of biological significance, and may help select CB units and identify patients at risk of delayed recovery.

Preclinical evaluation of an automated closed fluid management device: Cytomate, for washing out DMSO from hematopoietic stem cell grafts after thawing.

Infusion of dimethylsulfoxide (DMSO) contained in cryopreserved and thawed hematopoietic stem cell (HSC) grafts is frequently associated with mild or moderate adverse reactions, and occasionally with more severe events including neurological symptoms. The severity of these complications is related to the amount of residual DMSO. We evaluated a recently available, closed, automated and 'cgmp (current good manufacturing practice) compliant' device (CytoMate) for its ability to wash out DMSO at the expense of a limited loss of viable CD34(+) cells. A total of 16 procedures were carried out with 39 blood HSC bags intended for destruction. Mean amounts of DMSO for each cellular product (one, two or three bags) were between 12.2 and 39.6 g before thawing; after the washing procedure, residual DMSO quantities were between 0.1 and 3.7 g. When set up to reproducibly allow for a more than 96% elimination of DMSO, processing of thawed cells with the CytoMate cell processor resulted in a mean recovery of viable total cells, CD34(+) cells and lymphocyte subsets above 60%. We conclude that this simple and efficient washing technique is suitable for routine processing of HSC grafts. Clinical studies will demonstrate whether a reduction in the incidence of adverse effects associated with DMSO infusion is observed.

[Tumor-induced immunosuppression]. / Immunitè antitumorale et tolérance immunitaire.

Tumor immunology is based on two essential concepts: immune surveillance, which implicate the host immune reactions against tumor cells, and tumor immune escape, which refers to the tumor-cell evasion process against the host immune system. The notion that a deficit in immune cell functions permits tumor growth has received experimental support with the discovery of several different biochemical defects in T lymphocytes that infiltrate cancers. Furthermore, expression of self-antigens on the tumor surface impose potential barriers to the development of effective immune response. Tumors are able to overcome immune surveillance by changing the polarity of effectors cells, thus down-regulating the proliferation of tumor-specific cytotoxic T cells, or altering the effector compositions of immune cells within the tumor milieu, or both. Understanding the interaction between cancer cells and host immune cells is of importance for clinical applications or immunotherapy in cancer treatment.