Management of adults and children receiving CAR T-cell therapy: 2021 best practice recommendations of the European Society for Blood and Marrow Transplantation (EBMT) and the Joint Accreditation Committee of ISCT and EBMT (JACIE) and the European Haematology Association (EHA).

BACKGROUND: Several commercial and academic autologous chimeric antigen receptor T-cell (CAR-T) products targeting CD19 have been approved in Europe for relapsed/refractory B-cell acute lymphoblastic leukemia, high-grade B-cell lymphoma and mantle cell lymphoma. Products for other diseases such as multiple myeloma and follicular lymphoma are likely to be approved by the European Medicines Agency in the near future. DESIGN: The European Society for Blood and Marrow Transplantation (EBMT)-Joint Accreditation Committee of ISCT and EBMT (JACIE) and the European Haematology Association collaborated to draft best practice recommendations based on the current literature to support health care professionals in delivering consistent, high-quality care in this rapidly moving field. RESULTS: Thirty-six CAR-T experts (medical, nursing, pharmacy/laboratory) assembled to draft recommendations to cover all aspects of CAR-T patient care and supply chain management, from patient selection to long-term follow-up, post-authorisation safety surveillance and regulatory issues. CONCLUSIONS: We provide practical, clinically relevant recommendations on the use of these high-cost, logistically complex therapies for haematologists/oncologists, nurses and other stakeholders including pharmacists and health sector administrators involved in the delivery of CAR-T in the clinic.

Development of adaptive immune effector therapies in solid tumors.

State-of-the-art treatment strategies have drastically ameliorated the outcome of patients affected by cancer. However, resistant and recurrent solid tumors are generally nonresponsive to conventional therapies. A central factor in the sequence of events that lead to cancer is an alteration in antitumor immune surveillance, which results in failure to recognize and eliminate the transformed tumor cell. A greater understanding of the dysregulation and evasion of the immune system in the evolution and progression of cancer provides the basis for improved therapies. Targeted strategies, such as T-cell therapy, not only generally spare normal tissues, but also use alternative antineoplastic mechanisms that synergize with other therapeutics. Despite encouraging success in hematologic malignancies, adaptive cellular therapies for solid tumors face unique challenges because of the immunosuppressive tumor microenvironment, and the hurdle of T-cell trafficking within scarcely accessible tumor sites. This review provides a brief overview of current cellular therapeutic strategies for solid tumors, research carried out to increase efficacy and safety, and results from ongoing clinical trials.

Clinical pharmacology of CAR-T cells: Linking cellular pharmacodynamics to pharmacokinetics and antitumor effects.

Adoptive cell transfer of T cells genetically modified with tumor-reactive chimeric antigen receptors (CARs) is a rapidly emerging field in oncology, which in preliminary clinical trials has already shown striking antitumor efficacy. Despite these premises, there are still a number of open issues related to CAR-T cells, spanning from their exact mechanism of action (pharmacodynamics), to the factors associated with their in vivo persistence (pharmacokinetics), and, finally, to the relative contribution of each of the two in determining the antitumor effects and accompanying toxicities. In light of the unprecedented curative potential of CAR-T cells and of their predicted wide availability in the next few years, in this review we will summarize the current knowledge on the clinical pharmacology aspects of what is anticipated to be a brand new class of biopharmaceuticals to join the therapeutic armamentarium of cancer doctors.

Hepcidin and ferritin blood level as noninvasive tools for predicting breast cancer.

BACKGROUND: Currently used CA15-3 and CEA have found their clinical application particularly in the follow-up of patients with advanced disease. Novel biomarkers are urgent, especially for improving early diagnosis as well as for discriminating between benign and malignant disease. PATIENTS AND METHODS: In the present study, we used a proteomic approach based on surface-enhanced laser desorption/ionization-time of flight-mass spectrometry screening with the aim of identifying differentially expressed 2-30 kDa proteins in plasma of patients with malignant (65 cases) and benign (88 cases) breast lesions with respect to 121 healthy controls. RESULTS: We found that the most promising SELDI peaks were those corresponding to hepcidin-25 and ferritin light chain. We evaluated the capability of these peaks in predicting malignant and benign breast lesions using the area under the receiver operating characteristic curve (AUC). The results showed a good capacity to predict malignant breast lesions for hepcidin-25 [AUC: 0.82; 95% confidence interval (CI) 0.75-0.90] and ferritin light chain (AUC: 0.86; 95% CI 0.79-0.92). Conversely, a weak and satisfactory capability to predict benign breast lesion was observed for hepcidin-25 (AUC: 0.63; 95% CI 0.41-0.85) and ferritin light chain (AUC: 0.73; 95% CI 0.49-0.97). A significant association between HER2 status and hepcidin-25 was observed and the distribution of transferrin and ferritin were found significantly different in patients with breast cancer when compared with that of controls. CONCLUSIONS: This study provides evidence that hepcidin and ferritin light chain level in plasma may be of clinical usefulness to predict malignant and benign disease with respect to healthy controls.

Synthesis and biological evaluation of new simple indolic non peptidic HIV Protease inhibitors: the effect of different substitution patterns.

New structurally simple indolic non peptidic HIV Protease inhibitors were synthesized from (S)-glycidol by regioselective methods. Following the concept of targeting the protein backbone, different substitution patterns were introduced onto the common stereodefined isopropanolamine core modifying the type of functional group on the indole, the position of the functional group on the indole and the type of the nitrogen containing group (sulfonamides or perhydroisoquinoline), alternatively. The systematic study on in vitro inhibition activity of such compounds confirmed the general beneficial effect of the 5-indolyl substituents in presence of arylsulfonamide moieties, which furnished activities in the micromolar range. Preliminary docking analysis allowed to identify several key features of the binding mode of such compounds to the protease.

Regulatory T cells expressing CD19-targeted chimeric antigen receptor restore homeostasis in Systemic Lupus Erythematosus.

Systemic Lupus Erythematosus (SLE) is a progressive disease leading to immune-mediated tissue damage, associated with an alteration of lymphoid organs. Therapeutic strategies involving regulatory T (Treg) lymphocytes, which physiologically quench autoimmunity and support long-term immune tolerance, are considered, as conventional treatment often fails. We describe here a therapeutic strategy based on Tregs overexpressing FoxP3 and harboring anti-CD19 CAR (Fox19CAR-Tregs). Fox19CAR-Tregs efficiently suppress proliferation and activity of B cells in vitro, which are relevant for SLE pathogenesis. In an humanized mouse model of SLE, a single infusion of Fox19CAR-Tregs restricts autoantibody generation, delay lymphopenia (a key feature of SLE) and restore the human immune system composition in lymphoid organs, without detectable toxicity. Although a short survival, SLE target organs appear to be protected. In summary, Fox19CAR-Tregs can break the vicious cycle leading to autoimmunity and persistent tissue damage, representing an efficacious and safe strategy allowing restoration of homeostasis in SLE.

Genetic engineering of T cells for the immunotherapy of haematological malignancies.

Accumulating experimental and clinical evidence has been obtained over recent years in support of the notion that the immune system has the potential to cure cancer. The most convincing example is the graft versus leukaemia effect observed after allogeneic haematopoietic stem cell transplantation. In the autologous setting, however, the isolation and expansion of naturally occurring tumour-specific T cells is a challenging task. Cancer antigens are often self-antigens and cancer-specific T cells are thus subject to selective mechanisms of central and peripheral tolerance. The significant advances in gene-transfer technologies developed over the last decade have offered new tools to overcome these limitations. Natural T cells can be genetically modified to generate high numbers of 'supernatural' tumour-reactive T cells from virtually every cancer patient. Supernatural T cells may express clonal receptors providing new specificities, factors increasing T-cell performance or safety factors enabling their elimination in case of toxicity. Technological improvements applied to novel concepts of T-cell biology and oncogenesis will allow to simultaneously equip T cells with different transgenes and expand a real 'army' of lymphocytes trained to selectively eradicate cancer cells.

Progress and prospects: graft-versus-host disease.

Graft-versus-host disease (GvHD) is one of the major complications of allogeneic hematopoietic stem cell transplantation, an otherwise highly effective therapeutic modality for patients affected by hematological diseases. The main inducers of GvHD are alloreactive donor T cells, which recognize host antigens presented by recipient cells. The critical role of lymphocytes in GvHD is well documented by the observation that T-cell depletion from the graft prevents GvHD. Unfortunately, the removal of donor lymphocytes from the graft increases the incidence of disease relapse and life-threatening infectious complications. Gene transfer technologies are promising tools to manipulate donor T-cell immunity to enforce graft-versus-tumor/graft-versus-infection while preventing or controlling GvHD. For this purpose, several cell and gene transfer approaches have been investigated at the preclinical level and implemented in clinical trials.

HSV-TK gene transfer into donor lymphocytes for control of allogeneic graft-versus-leukemia.

In allogeneic bone marrow transplantation (allo-BMT), donor lymphocytes play a central therapeutic role in both graft-versus-leukemia (GvL) and immune reconstitution. However, their use is limited by the risk of severe graft-versus-host disease (GvHD). Eight patients who relapsed or developed Epstein-Barr virus-induced lymphoma after T cell-depleted BMT were then treated with donor lymphocytes transduced with the herpes simplex virus thymidine kinase (HSV-TK) suicide gene. The transduced lymphocytes survived for up to 12 months, resulting in antitumor activity in five patients. Three patients developed GvHD, which could be effectively controlled by ganciclovir-induced elimination of the transduced cells. These data show that genetic manipulation of donor lymphocytes may increase the efficacy and safety of allo-BMT and expand its application to a larger number of patients.

T cells for suicide gene therapy: activation, functionality and clinical relevance.

In order to control graft-versus-host disease after donor lymphocyte infusion, T cells can be retrovirally transduced with a suicide gene. However, the immune competence of activated T cells appears compromised, responsible for reduced alloreactivity. The present study compared different activation protocols using soluble or bead-coupled antibodies regarding T-cell subtype expansion capacity and functionality. T cells were purified on a laboratory and clinical scale using both CD3 and CD4/CD8 antibodies for selection, leading to a mean purity of 96%. Transductions were performed with a GMP-grade CD34/HSV-TK vector. Activation with soluble CD3/CD28-antibodies +1000 U/ml IL-2 induced a 50-fold expansion of T cells over 14 days, whereas T cells activated with bead-coupled antibodies only expanded 2-4-fold restricted to the first week. Apart from using soluble antibodies, proliferation was highly IL-2 dependent. Expansion of CMV-specific T cells coincided with the expansion of whole CD3(+) cells. Soluble antibodies and higher IL-2 concentrations preferentially stimulated CD8(+) T cells, while bead-coupled antibodies +20 U/ml IL-2 preserved the CD4/CD8 ratio. Irrespective of the activation protocol, there was a shift from a naive to memory phenotype. When activated with soluble antibodies, mainly CD8(+) T cells were transduced. Furthermore, Th1/Th2 cytokine secretion was reduced. In contrast, CD4(+)/CD8(+) T cells activated with bead-coupled antibodies were rather homogenously transduced and cytokine secretion did not appear to be affected.

Impact of drug development on the use of stem cell transplantation: a report by the European Society for Blood and Marrow Transplantation (EBMT).

Hematopoietic stem cell transplantation (HSCT) is used with increasing frequency in Europe with 40 000 transplants reported in 2014. Transplant-related mortality remains high in allogeneic HSCT (10-20%); high-dose chemotherapy is toxic and demanding for patients. Drug development is accelerating and with limited toxicity of some targeted drugs may replace HSCT, whereas others may function as a 'bridge to transplant'. We analyzed HSCT reported to the activity survey for selected diseases in which major advances in drug development have been made. Tyrosine kinase inhibitors markedly changed the number of allogeneic HSCT in early CML. In myelodysplastic syndromes, hypomethylating agents show no effect on HSCT activity and Janus kinase inhibitors for myeloproliferative neoplasm appear to have only a temporary effect. For CLL autologous HSCT decreased after publication of trials showing improved PFS but no overall survival advantage and allogeneic rates are dropping after the introduction of Bruton kinase and PI3K Inhibitors. Whether these are 'game changers' as was imatinib for CML requires additional follow-up. For myeloma, proteasome inhibitors and new immunomodulatory drugs do not appear to impact transplant rates. Drug development data show different effects on HSCT use; highly effective drugs may replace HSCT, whereas other drugs may improve the patient's condition to allow for HSCT.

Use of haploidentical stem cell transplantation continues to increase: the 2015 European Society for Blood and Marrow Transplant activity survey report.

Hematopoietic stem cell transplantation (HSCT) is an established procedure for many acquired and congenital disorders of the hematopoietic system. A record number of 42 171 HSCT in 37 626 patients (16 030 allogeneic (43%), 21 596 autologous (57%)) were reported by 655 centers in 48 countries in 2015. Trends include continued growth in transplant activity over the last decade, with the highest percentage increase seen in middle-income countries but the highest absolute growth in the very-high-income countries in Europe. Main indications for HSCT were myeloid malignancies 9413 (25%; 96% allogeneic), lymphoid malignancies 24 304 (67%; 20% allogeneic), solid tumors 1516 (4%; 3% allogeneic) and non-malignant disorders 2208 (6%; 90% allogeneic). Remarkable is the decreasing use of allogeneic HSCT for CLL from 504 patients in 2011 to 255 in 2015, most likely to be due to new drugs. Use of haploidentical donors for allogeneic HSCT continues to grow: 2012 in 2015, a 291% increase since 2005. Growth is seen for all diseases. In AML, haploidentical HSCT increases similarly for patients with advanced disease and for those in CR1. Both marrow and peripheral blood are used as the stem cell source for haploidentical HSCT with higher numbers reported for the latter.

Hematopoietic stem cell transplantation in Europe 2014: more than 40 000 transplants annually.

A record number of 40 829 hematopoietic stem cell transplantation (HSCT) in 36 469 patients (15 765 allogeneic (43%), 20 704 autologous (57%)) were reported by 656 centers in 47 countries to the 2014 survey. Trends include: continued growth in transplant activity, more so in Eastern European countries than in the west; a continued increase in the use of haploidentical family donors (by 25%) and slower growth for unrelated donor HSCT. The use of cord blood as a stem cell source has decreased again in 2014. Main indications for HSCT were leukemias: 11 853 (33%; 96% allogeneic); lymphoid neoplasias; 20 802 (57%; 11% allogeneic); solid tumors; 1458 (4%; 3% allogeneic) and non-malignant disorders; 2203 (6%; 88% allogeneic). Changes in transplant activity include more allogeneic HSCT for AML in CR1, myeloproliferative neoplasm (MPN) and aplastic anemia and decreasing use in CLL; and more autologous HSCT for plasma cell disorders and in particular for amyloidosis. In addition, data on numbers of teams doing alternative donor transplants, allogeneic after autologous HSCT, autologous cord blood transplants are presented.

Cell-based strategies to manage leukemia relapse: efficacy and feasibility of immunotherapy approaches.

When treatment fails, the clinical outcome of acute leukemia patients is usually very poor, particularly when failure occurs after transplantation. A second allogeneic stem cell transplant could be envisaged as an effective and feasible salvage option in younger patients having a late relapse and an available donor. Unmanipulated or minimally manipulated donor T cells may also be effective in a minority of patients but the main limit remains the induction of severe graft-versus-host disease. This clinical complication has brought about a huge research effort that led to the development of leukemia-specific T-cell therapy aiming at the direct recognition of leukemia-specific rather than minor histocompatibility antigens. Despite a great scientific interest, the clinical feasibility of such an approach has proven to be quite problematic. To overcome this limitation, more research has moved toward the choice of targeting commonly expressed hematopoietic specific antigens by the genetic modification of unselected T cells. The best example of this is represented by the anti-CD19 chimeric antigen receptor (CD19.CAR) T cells. As a possible alternative to the genetic manipulation of unselected T cells, specific T-cell subpopulations with in vivo favorable homing and long-term survival properties have been genetically modified by CAR molecules. Finally, the use of naturally cytotoxic effector cells such as natural killer and cytokine-induced killer cells has been proposed in several clinical trials. The clinical development of these latter cells could also be further expanded by additional genetic modifications using the CAR technology.

Haploidentical HSCT: a 15-year experience at San Raffaele.

Hematopoietic SCT (HSCT) from HLA haploidentical family donors is a promising therapy for high-risk hematological malignancies. In the past 15 years at San Raffaele Scientific Institute, we investigated several transplant platforms and post transplant cellular-based interventions. We showed that T cell-depleted haploidentical transplantation followed by the infusion of genetically modified donor T cells (TK007 study, Eudract-2005-003587-34) promotes fast and wide immune reconstitution and GvHD control. This approach is currently tested in a phase III multicenter randomized trial (TK008 study, NCT00914628). We targeted patients with advanced leukemia with a sirolimus-based, calcineurin inhibitor-free prophylaxis of GvHD to allow the safe infusion of unmanipulated PBSCs from haploidentical family donors (TrRaMM study, Eudract 2007-5477-54). Results of these approaches are summarized and discussed.

Hematopoietic SCT in Europe 2013: recent trends in the use of alternative donors showing more haploidentical donors but fewer cord blood transplants.

A record number of 39,209 HSCT in 34,809 patients (14,950 allogeneic (43%) and 19,859 autologous (57%)) were reported by 658 centers in 48 countries to the 2013 survey. Trends include: more growth in allogeneic than in autologous HSCT, increasing use of sibling and unrelated donors and a pronounced increase in haploidentical family donors when compared with cord blood donors for those patients without a matched related or unrelated donor. Main indications were leukemias, 11,190 (32%; 96% allogeneic); lymphoid neoplasias, 19,958 (57%; 11% allogeneic); solid tumors, 1543 (4%; 4% allogeneic); and nonmalignant disorders, 1975 (6%; 91% allogeneic). In patients without a matched sibling or unrelated donor, alternative donors are used. Since 2010 there has been a marked increase of 96% in the number of transplants performed from haploidentical relatives (802 in 2010 to 1571 in 2013), whereas the number of unrelated cord blood transplants has slightly decreased (789 in 2010 to 666 in 2013). The use of donor type varies greatly throughout Europe.

Incidence, risk factors and clinical outcome of leukemia relapses with loss of the mismatched HLA after partially incompatible hematopoietic stem cell transplantation.

Genomic loss of the mismatched human leukocyte antigen (HLA) is a recently described mechanism of leukemia immune escape and relapse after allogeneic hematopoietic stem cell transplantation (HSCT). Here we first evaluated its incidence, risk factors and outcome in 233 consecutive transplants from partially HLA-mismatched related and unrelated donors (MMRD and MMUD, respectively). We documented 84 relapses, 23 of which with HLA loss. All the HLA loss relapses occurred after MMRD HSCT, and 20/23 in patients with acute myeloid leukemia. Upon MMRD HSCT, HLA loss variants accounted for 33% of the relapses (23/69), occurring later than their 'classical' counterparts (median: 307 vs 88 days, P<0.0001). Active disease at HSCT increased the risk of HLA loss (hazard ratio (HR): 10.16; confidence interval (CI): 2.65-38.92; P=0.001), whereas older patient ages had a protective role (HR: 0.16; CI: 0.05-0.46; P=0.001). A weaker association with HLA loss was observed for graft T-cell dose and occurrence of chronic graft-versus-host disease. Outcome after 'classical' and HLA loss relapses was similarly poor, and second transplantation from a different donor appeared to provide a slight advantage for survival. In conclusion, HLA loss is a frequent mechanism of evasion from T-cell alloreactivity and relapse in patients with myeloid malignancies transplanted from MMRDs, warranting routine screening in this transplantation setting.

Sirolimus-based graft-versus-host disease prophylaxis promotes the in vivo expansion of regulatory T cells and permits peripheral blood stem cell transplantation from haploidentical donors.

Hematopoietic stem cell transplantation (HSCT) from human leukocyte antigen (HLA) haploidentical family donors is a promising therapeutic option for high-risk hematologic malignancies. Here we explored in 121 patients, mostly with advanced stage diseases, a sirolimus-based, calcineurin-inhibitor-free prophylaxis of graft-versus-host disease (GvHD) to allow the infusion of unmanipulated peripheral blood stem cell (PBSC) grafts from partially HLA-matched family donors (TrRaMM study, Eudract 2007-5477-54). Conditioning regimen was based on treosulfan and fludarabine, and GvHD prophylaxis on antithymocyte globulin Fresenius (ATG-F), rituximab and oral administration of sirolimus and mycophenolate. Neutrophil and platelet engraftment occurred in median at 17 and 19 days after HSCT, respectively, and full donor chimerism was documented in patients' bone marrow since the first post-transplant evaluation. T-cell immune reconstitution was rapid, and high frequencies of circulating functional T-regulatory cells (Treg) were documented during sirolimus prophylaxis. Incidence of acute GvHD grade II-IV was 35%, and occurrence and severity correlated negatively with Treg frequency. Chronic GvHD incidence was 47%. At 3 years after HSCT, transpant-related mortality was 31%, relapse incidence 48% and overall survival 25%. In conclusion, GvHD prophylaxis with sirolimus-mycophenolate-ATG-F-rituximab promotes a rapid immune reconstitution skewed toward Tregs, allowing the infusion of unmanipulated haploidentical PBSC grafts.

Herpes simplex virus thymidine kinase gene transfer for controlled graft-versus-host disease and graft-versus-leukemia: clinical follow-up and improved new vectors.

We previously demonstrated that severe graft-versus-host disease (GvHD), associated with the therapeutic infusion of donor lymphocytes after allogeneic marrow transplantation (BMT), can be efficiently controlled by the SFCMM-2-mediated expression of the herpes simplex virus thymidine kinase (HSV-tk) suicide gene into the allogeneic lymphocytes. This was achieved by selective elimination of transduced lymphocytes by ganciclovir (GCV) infusion. Despite the positive results of the pilot clinical trial, two vector-related limitations were observed. The induction of a strong immune response against genetically modified cells was observed in two patients. In addition, the only patient who developed chronic GvHD showed only partial response to ganciclovir treatment. In an attempt to overcome these limitations, we developed a new generation of vectors. The neomycin resistance (neoR) gene was removed from the SFCMM-3 and SFCMM-4 retroviral vectors. These vectors are less immunogenic and able to confer higher ganciclovir sensitivity to transduced human lymphocytes. All the vectors carry a modified form of the low-affinity nerve growth factor receptor cDNA, as cell surface selectable marker (deltaLNGFR). The vectors were compared in terms of gene transfer efficiency, and ability to confer high and specific sensitivity to ganciclovir. The SFCMM-3 vector, carrying the entire HSV-tk gene driven by the LTR promoter, allows efficient transduction of human T lymphocytes and confers the highest GCV sensitivity to transduced lymphocytes with a high and a low proliferation index. The expression of the deltaLNGFR marker allows an easier in vitro manipulation and a faster immune selection of transduced cells compared with neoR selection. Finally, the elimination of the neoR gene removes a potent immunogen from transduced lymphocytes.