No abstract

By late 2018, 2 chimeric antigen receptor T (CAR T) cell products have been approved by US and European regulatory authorities. Tisagenlecleucel (Kymriah, Novartis) is indicated in the treatment of patients up to 25 years of age with B-cell acute lymphoblastic leukemia (ALL) that is refractory or in second or later relapse, or adult patients with large B-cell lymphoma relapsed or refractory (r/r) after 2 or more lines of systemic therapy, including diffuse large B-cell lymphoma (DLBCL) not otherwise specified, high grade B-cell lymphoma and DLBCL arising from follicular lymphoma. Axicabtagene ciloleucel (Yescarta, Kite) is indicated for the treatment of adult patients with large B-cell lymphoma relapsed or refractory after 2 or more lines of systemic therapy, including DLBCL not otherwise specified, primary mediastinal large B-cell lymphoma, high grade B-cell lymphoma, and DLBCL arising from follicular lymphoma (ZUMA-1 trial).This review will offer a practical guide for the recognition and management of the most important toxicities related to the use of the current commercial CAR T cells, and also highlight strategies to diminish these side effects in the future.

Key Points• Use of different grading systems leads to inconsistent CAR T-cell toxicity rates, with possible implications for disease management.• A unified grading system should be used in clinical practice and trials, and related management guidelines should be developed. Various grading systems are currently used for chimeric antigen receptor (CAR) T-cell-related toxicity, cytokine release syndrome (CRS), and immune effector cell-associated neurotoxicity syndrome (ICANS). We compared the recently proposed American Society for Transplantation and Cellular Therapy (ASTCT) grading system to other grading scores in 2 populations of adults: patients (n 5 53) with B-cell acute lymphoblastic leukemia (B-ALL) treated with 1928z CAR T-cells (clinicaltrials.gov #NCT01044069), and patients (n 5 49) with diffuse large B-cell lymphoma (DLBCL) treated with axicabtagene-ciloleucel (axi-cel) or tisagenlecleucel after US Food and Drug Administration approval. According to ASTCT grading, 82% of patients had CRS, 87% in the B-ALL and 77% in the DLBCL groups (axi-cel: 86%, tisagenlecleucel: 54%), whereas 50% of patients experienced ICANS, 55% in the B-ALL and 45% in the DLBCL groups (axi-cel: 55%, tisagenlecleucel: 15%). All grading systems agreed on CRS and ICANS diagnosis in 99%and 91% of cases, respectively. However, when analyzed grade by grade, only 25% and 54% of patients had the same grade in each system for CRS and ICANS, respectively, as different systems score symptoms differently (upgrading or downgrading their severity), leading to inconsistent final grades. Investigation of possible management implications in DLBCL patients showed that different recommendations on tocilizumab and steroids across current guidelines potentially result in either overtreating or delaying treatment. Moreover, because these guidelines are based on single products and different grading systems, they cannot be universally applied. To avoid discrepancies in assessing and managing toxicities of different products, we propose that unified grading be used across clinical trials and in practice and that paired management guidelines with product-specific indications be developed.

Research on CAR T cells has achieved enormous progress in recent years. After the impressive results obtained in relapsed and refractory B-cell acute lymphoblastic leukemia and aggressive B-cell lymphomas, two constructs, tisagenlecleucel and axicabtagene ciloleucel, were approved by FDA. The role of CAR T cells in the treatment of B-cell disorders, however, is rapidly evolving. Ongoing clinical trials aim at comparing CAR T cells with standard treatment options and at evaluating their efficacy earlier in the disease course. The use of CAR T cells is still limited by the risk of relevant toxicities, most commonly cytokine release syndrome and neurotoxicity, whose management has nonetheless significantly improved. Some patients do not respond or relapse after treatment, either because of poor CAR T-cell expansion, lack of anti-tumor effects or after the loss of the target antigen on tumor cells. Investigators are trying to overcome these hurdles in many ways: by testing constructs which target different and/or multiple antigens or by improving CAR T-cell structure with additional functions and synergistic molecules. Alternative cell sources including allogeneic products (off-the-shelf CAR T cells), NK cells, and T cells obtained from induced pluripotent stem cells are also considered. Several trials are exploring the curative potential of CAR T cells in other malignancies, and recent data on multiple myeloma and chronic lymphocytic leukemia are encouraging. Given the likely expansion of CAR T-cell indications and their wider availability over time, more and more highly specialized clinical centers, with dedicated clinical units, will be required. Overall, the costs of these cell therapies will also play a role in the sustainability of many health care systems. This review will focus on the major clinical trials of CAR T cells in B-cell malignancies, including those leading to the first Cerrano et al. CART Research and Clinical Practice FDA approvals, and on the new settings in which these constructs are being tested. Besides, the most promising approaches to improve CAR T-cell efficacy and early data on alternative cell sources will be reviewed. Finally, we will discuss the challenges and the opportunities that are emerging with the advent of CAR T cells into clinical routine.

Patients who develop CAR T-cells-related severe cytokine release syndrome (CRS) and immune-effector-cells-associated neurotoxicity syndrome (ICANS) exhibit hemodynamic instability and endothelial activation. The EASIX (Endothelial-Activation and Stress-Index) score [lactate dehydrogenase (LDH, U/L) x  creatinine (mg/dL) / platelets (10^9 cells/L)] is a marker of endothelial damage that correlates with outcomes in allogeneic hematopoietic cell transplantation. Elevated LDH and low platelets have been associated with severe CRS and ICANS, as has C-reactive protein (CRP), while increased creatinine is seen only in a minority of advanced severe CRS cases. We hypothesized that EASIX and two new modified EASIX formulas [simplified-EASIX, which excludes creatinine, and modified-EASIX (m-EASIX), which replaces creatinine with CRP (mg/dL)], calculated peri CAR T-cells infusion, would be associated with development of severe (grade ≥3) CRS and ICANS. We included 118 adults, 53 with B-acute lymphoblastic leukemia treated with 1928z CAR T-cells (NCT01044069) and 65 with diffuse large B-cell lymphoma treated with axicabtagene-ciloleucel or tisagenlecleucel. The three formulas showed similar predictive power for severe CRS and ICANS. However, low platelets and high CRP values were the only variables individually correlated with these toxicities. Moreover, only m-EASIX was a significant predictor of disease response. m-EASIX could discriminate patients who subsequently developed severe CRS preceding the onset of severe symptoms (AUC: at lymphodepletion 80.4%, day -1 73.0%, day +1 75.4%). At day +3, it also had high discriminatory ability for severe ICANS (AUC 73%). We propose m-EASIX as a clinical tool to potentially guide individualized management of patients at higher risk for severe CAR T-cells-related toxicities.

Individual comorbidities have distinct contributions to non-relapse mortality (NRM) following allogeneic hematopoietic cell transplantation (allo-HCT). We studied the impact of comorbidities both individually and in combination in a single-center cohort of 573 adult patients who underwent CD34-selected allo-HCT following myeloablative conditioning. Pulmonary disease, moderate to severe hepatic comorbidity, cardiac disease of any type, and renal dysfunction were associated with increased NRM in multivariable Cox regression models. A Simplified Comorbidity Index (SCI) composed of the four comorbidities predictive of NRM, as well as age > 60 years, stratified patients into five groups with a stepwise increase in NRM. NRM rates ranged from 11.4% to 49.9% by stratum, with adjusted hazard ratios of 1.84, 2.59, 3.57, and 5.38. The SCI was also applicable in an external cohort of 230 patients who underwent allo-HCT with unmanipulated grafts following intermediate-intensity conditioning. The area under the ROC curve (AUC) of the SCI for 1-year NRM was 70.3 and 72.0 over the development and external-validation cohorts, respectively; corresponding AUCs of the Hematopoietic Cell Transplantation-specific Comorbidity Index (HCT-CI) were 61.7 and 65.7. In summary, a small set of comorbidities, aggregated into the Simplified Comorbidity Index, are highly predictive of NRM. The new index stratifies patients into distinct risk groups, was validated in an external cohort, and provides higher discrimination than the HCT-CI.

Chimeric antigenreceptor (CAR) T cell therapy has demonstrated efficacy in B cell malignancies, particularly for acute lymphoblastic leukaemia (ALL) and non‑Hodgkin lymphomas. However, this regimen is not harmless and, in some patients, can lead to a multi organ failure. For this reason, the knowledge and the early recognition and management of the side effects related to CAR-T cell therapy for the staff is mandatory. In this review, we have summarised the current recommendations for the identification, gradation and management of the cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome, as well as infections, and related to CAR-T cell therapy.

Keywords Allogeneic transplantation; endothelial damage; biomarkers. Background Endothelial damage is associated with severe complications and increased risk of death after allogeneic hematopoietic cell transplantation (AlloHCT). The recently developed Endothelial Activation and Stress Index (EASIX) is a prognostic tool that uses clinical lab values and has been shown to predict non-relapse mortality (NRM) and overall survival (OS) at onset of acute graft versus host disease (aGVHD) in reduced intensity (RIC) alloHCT (Luft, Lancet Haematol 2017). We hypothesized that EASIX may be valuable for more broadly predicting aGVHD, NRM and OS after AlloHCT, beyond time of onset of aGVHD. Design We evaluated 152 adult patients who received an unmodified RIC AlloHCT from a related or unrelated donor with uniform GVHD prophylaxis of sirolimus/tacrolimus and low-dose MTX for treatment of lymphoid malignancies, between April 2008 and May 2017. The EASIX formula (LDH*Creatinine/platelet counts) was calculated at multiple timepoints (pre-HCT, day 30, day 100, onset TMA and aGVHD). For all EASIX assessments post-HCT, a landmark analysis was conducted at the given timepoint A log transformation using base 2 (log2) was applied to all EASIX variables to reduce skew. A one-unit increase in log2 EASIX is associated with a doubling (one-fold increase) of EASIX on the original scale. Kaplan-Meier, cumulative incidence, and cox modeling (cause specific for NRM and aGVHD) were used to evaluate EASIX as it relates to outcomes of interest. Relapse and death or relapse were considered competing risks for NRM and aGVHD respectively. Results The median age at transplant was 54 years (range 23-78), 70% were males, a majority had non-Hodgkin lymphoma (68%), and most had sensitive disease at time of HCT (CR=56%; PR=33%). All patients, except two, received peripheral blood stem cells. Sixty-three patients had an HLA-identical related donor, while the remaining 89 had an unrelated donor transplant (HLA-matched in 75 patients, and HLA-mismatched in 14 patients). HCT-CI was 0 in 49 patients, 1-2 in 41 and ≥ 3 in 62 patients. With a median follow-up in surviving patients of 5.4 years (range, 0.8-10), the 1 and 3 years OS rate was 84.2% (95% CI, 77.3-89.1) and 67.9% (95% CI, 59.6-74.8), respectively. The NRM rate at 1 and 3 years was 7.9% (95% CI, 4.3-12.9) and 16.4% (95% CI, 10.9-22.8), respectively. The 1-year cumulative incidences of grades 1-4, 2-4 and 3-4 aGVHD were 56.6% (95% CI, 48.3-64.1), 42.1% (95% CI, 34.2-49.8) and 7.9% (95% CI, 4.3-12.9), respectively. Post-HCT thrombotic microangiopathy was only observed in 13 patients, representing too few events for EASIX analysis. As expected, HCT-CI was significantly associated with both OS and NRM. Pre-HCT EASIX was significantly associated with increased NRM (HR=1.60 [95% CI, 1.15-2.23], p=0.005) and aGVHD grade 1-4 and 2-4 (HR=1.33 [95% CI, 1.08-1.64], p=0.006 and HR=1.39 [95% CI, 1.10-1.75], p=0.005; respectively), but not OS or grade 3-4 aGVHD (Table 1). EASIX at day 30 and day 100 was significantly associated with both OS and NRM (Figures 1-4). Furthermore, confirming the results of Luft, EASIX calculated at onset of any grade aGVHD was significantly associated with OS (HR=1.34 [1.10-1.63], p=0.004) and NRM (HR=1.47 1.11-1.94], p=0.007). Finally, there was no correlation between HCT-CI and EASIX score. Conclusions We conclude that the EASIX formula, calculated at various timepoints pre and post AlloHCT, is significantly associated with NRM and OS. Pre-HCT EASIX also predicts risk of aGVHD, confirming prior results, EASIX at onset of acute GVHD is a predictor of NRM and OS in adult recipients RIC AlloHCT. EASIX provides an independent and easily accessible tool to predict important AlloHCT outcomes that can be used in addition to HCT-CI to better risk stratify patients. Disclosures Sauter: Juno Therapeutics: Consultancy, Research Funding; Sanofi-Genzyme: Consultancy, Research Funding; Spectrum Pharmaceuticals: Consultancy; Novartis: Consultancy; Precision Biosciences: Consultancy; Kite: Consultancy. Perales:Incyte: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees and Clinical trial support; Merck: Other: Personal fees; Takeda: Other: Personal fees; Abbvie: Other: Personal fees; Novartis: Other: Personal fees.