BACKGROUND. T cells expressing antigen-specific chimeric antigen receptors (CARs) improve outcomes for CD19-expressing B cell malignancies. We evaluated a human application of T cells that were genetically modified using the Sleeping Beauty (SB) transposon/transposase system to express a CD19-specific CAR. METHODS. T cells were genetically modified using DNA plasmids from the SB platform to stably express a second-generation CD19-specific CAR and selectively propagated ex vivo with activating and propagating cells (AaPCs) and cytokines. Twenty-six patients with advanced non-Hodgkin lymphoma and acute lymphoblastic leukemia safely underwent hematopoietic stem cell transplantation (HSCT) and infusion of CAR T cells as adjuvant therapy in the autologous (n = 7) or allogeneic settings (n = 19). RESULTS. SB-mediated genetic transposition and stimulation resulted in 2,200- to 2,500-fold ex vivo expansion of genetically modified T cells, with 84% CAR expression, and without integration hotspots. Following autologous HSCT, the 30-month progression-free and overall survivals were 83% and 100%, respectively. After allogeneic HSCT, the respective 12-month rates were 53% and 63%. No acute or late toxicities and no exacerbation of graft-versus-host disease were observed. Despite a low antigen burden and unsupportive recipient cytokine environment, CAR T cells persisted for an average of 201 days for autologous recipients and 51 days for allogeneic recipients. CONCLUSIONS. CD19-specific CAR T cells generated with SB and AaPC platforms were safe, and may provide additional cancer control as planned infusions after HSCT. These results support further clinical development of this nonviral gene therapy approach. TRIAL REGISTRATION. Autologous, NCT00968760; allogeneic, NCT01497184; long-term follow-up, NCT01492036. FUNDING. National Cancer Institute, private foundations, and institutional funds. Please see Acknowledgments for details.

The unique immunomodulatory properties of mesenchymal stem cells (MSCs) make them a rationale agent to investigate for graft-versus-host disease (GVHD). Human MSCs were used to treat de novo acute GVHD (aGVHD). Patients with grades II-IV GVHD were randomized to receive 2 treatments of human MSCs (Prochymal(R)) at a dose of either 2 or 8 million MSCs/kg in combination with corticosteroids. Patients received GVHD prophylaxis with tacrolimus, cyclosporine, (CsA) or mycophenolate mofetil (MMF). Study endpoints included safety of Prochymal administration, induction of response to Prochymal, and overall response of aGVHD by day 28, and long-term safety. Thirty-two patients were enrolled, with 31 evaluable: 21 males, 10 females; median age 52 years (range: 34-67). Twenty-one patients had grade II, 8 had grade III, and 3 had grade IV aGVHD. Ninety-four percent of patients had an initial response to Prochymal (77% complete response [CR] and 16% partial response [PR]). No infusional toxicities or ectopic tissue formations were reported. There was no difference with respect to safety or efficacy between the low and high Prochymal dose. In conclusion, Prochymal can be infused safely into patients with aGVHD and induces response in a high proportion of GVHD patients.

Uncontrolled studies have suggested that bone marrow-derived mesenchymal stem cells (MSCs) may be effective against acute graft-versus-host disease (aGVHD). We conducted a multicenter, randomized study to assess the efficacy of using ex vivo cultured adult human MSC (remestemcel-L) in addition to second-line therapy to treat steroid-refractory aGVHD (NCT00366145). In total, 260 patients, 6 months to 70 years of age, were enrolled from August 2006 to May 2009 and were randomized 2:1 to receive 8 intravenous infusions of remestemcel-L or placebo, given over 4 weeks, in addition to second-line therapy according to institutional standards. Four additional infusions over 4 weeks were indicated for patients with incomplete response at day 28. Randomization was stratified by aGVHD grade. Efficacy and safety were assessed through 180 days of follow-up, with the primary endpoint being durable complete response (DCR), defined as complete resolution of aGVHD symptoms for any period of at least 28 days after beginning treatment. Remestemcel-L did not meet the primary endpoint of greater DCR in the intent-to-treat population (35% versus 30%; P = 0.42). In post hoc analyses, patients with liver involvement who received at least 1 infusion of remestemcel-L had a higher DCR, and higher overall complete or partial response rate (OR) than those who received placebo (29% versus 5%; P = .047). Among high-risk patients (aGVHD grades C and D), remestemcel-L demonstrated significantly higher OR at day 28 than placebo (58% versus 37%; P = 0.03). Furthermore, pediatric patients had a higher OR with MSCs compared with placebo (64% versus 23%; P = .05). Similar rates of adverse events were observed between treatment groups. Remestemcel-L was safe and well tolerated. Results of this study did not demonstrate superior DCR compared with placebo when added to standard of care. The favorable clinical responses seen in some patient subsets may warrant further investigation.

The Endothelial Activation and Stress Index (EASIX) score, defined as [(creatinine × lactate dehydrogenase [LDH])/platelets], is a marker of endothelial activation that has been validated in the allogeneic hematopoietic stem cell transplant setting. Endothelial activation is one of the mechanisms driving immune-mediated toxicities in patients treated with chimeric antigen receptor-T (CAR-T)-cell therapy. This study’s objective was to evaluate the association between EASIX and other laboratory parameters collected before lymphodepletion and the subsequent onset of cytokine release syndrome (CRS) and immune effector cell–associated neurotoxicity syndrome (ICANS) those patients. Toxicity data were collected prospectively on 171 patients treated with axicabtagene ciloleucel (axi-cel) for large B-cell lymphoma (LBCL). CRS grades 2 to 4 were diagnosed in 81 (47%) patients and ICANS grades 2 to 4 in 84 (49%). EASIX combined with ferritin (EASIX-F) identified 3 risk groups with CRS grades 2 to 4 cumulative incidence of 74% (hazards ratio [HR], 4.8; 95% confidence interval [CI], 2.1-11; P < .001), 49% (HR, 2.3; 95% CI, 1.02-5; P = .04), and 23% (reference), respectively. EASIX combined with CRP and ferritin (EASIX-FC) identified 3 risk groups with an ICANS grade 2 to 4 cumulative incidence of 74% (HR, 3.6; 95% CI, 1.9-6.9; P < .001), 51% (HR, 2.1; 95% CI, 1.1-3.9; P = .025), and 29% (reference). Our results indicate that common laboratory parameters before lymphodepletion correlate with CAR-T–related toxicities and can help support clinical decisions, such as preemptive toxicity management, hospitalization length, and proper setting for CAR-T administration.

Inotuzumab ozogamicin (InO), a humanized anti-CD22 monoclonal antibody conjugated to the cytotoxic antibiotic agent calicheamicin, has demonstrated efficacy in the phase 3 INO-VATE study of adults with relapsed or refractory acute lymphoblastic leukemia (ALL). Findings from the study showed clinically important adverse events (AEs) associated with InO, with veno-occlusive disease (VOD) reported as a major non-hematologic AE. Other important or serious AEs include neutropenia, febrile neutropenia, thrombocytopenia, infusion-related reactions, tumor lysis syndrome, and prolonged QT syndrome. This report summarizes the recommendations of an expert panel of hematologists and transplant physicians for evaluation and management of the important AEs associated with InO, with a focus on diagnosis, prevention, monitoring, and management of VOD. The possible interventions considered included prophylaxis medications, patient monitoring and assessment, and InO dose adjustment or discontinuation.

Patients with B-lineage acute lymphoblastic leukemia (ALL) are at high-risk for relapse after allogeneic hematopoietic cell transplantation (HCT). We conducted a single-center phase 2 study evaluating the feasibility of 4 cycles of blinatumomab administered every 3 months during the first year after HCT in an effort to mitigate relapse in high-risk ALL patients. Twenty-one of 23 enrolled patients received at least 1 cycle of blinatumomab and were included in the analysis. The median time from HCT to the first cycle of blinatumomab was 78 days (range, 44 to 105). Twelve patients (57%) completed all 4 treatment cycles. Neutropenia was the only grade 4 adverse event (19%). Rates of cytokine release (5% G1) and neurotoxicity (5% G2) were minimal. The cumulative incidence of acute graft-versus-host disease (GVHD) grades 2 to 4 and 3 to 4 were 33% and 5%, respectively; 2 cases of mild (10%) and 1 case of moderate (5%) chronic GVHD were noted. With a median follow-up of 14.3 months, the 1-year overall survival (OS), progression-free survival (PFS), and nonrelapse mortality (NRM) rates were 85%, 71%, and 0%, respectively. In a matched analysis with a contemporary cohort of 57 patients, we found no significant difference between groups regarding blinatumomab’s efficacy. Correlative studies of baseline and posttreatment samples identified patients with specific T-cell profiles as “responders” or “nonresponders” to therapy. Responders had higher proportions of effector memory CD8 T-cell subsets. Nonresponders were T-cell deficient and expressed more inhibitory checkpoint molecules, including T-cell immunoglobulin and mucin domain 3 (TIM3). We found that blinatumomab postallogeneic HCT is feasible, and its benefit is dependent on the immune milieu at time of treatment. This paper is posted on ClinicalTrials.gov, study ID: NCT02807883.