Combined heparin/acid citrate dextrose solution A anticoagulation in the Optia continuous mononuclear cell protocol for pediatric lymphocyte apheresis.

Collecting a sufficient number of T-cells is a critical first step in the production of chimeric antigen receptor (CAR)-T cells. Herein, we report a successful implementation of anticoagulation with combined heparin and acid citrate dextrose solution A (ACD-A) for the continuous mononuclear cell (CMNC) protocol on the Spectra Optia in a 20-month-old, 7.5 kg patient with refractory acute lymphoblastic leukemia for manufacture of tisagenlecleucel, a CAR-T cell therapy. Combined heparin/ACD-A was used following clotting issues when ACD-A was used alone during initial CMNC collections. To our knowledge, this is the first reported case in pediatrics of combined heparin/ACD-A anticoagulation with the Spectra Optia CMNC protocol.

Tisagenlecleucel in Children and Young Adults with B-Cell Lymphoblastic Leukemia.

BACKGROUND: In a single-center phase 1-2a study, the anti-CD19 chimeric antigen receptor (CAR) T-cell therapy tisagenlecleucel produced high rates of complete remission and was associated with serious but mainly reversible toxic effects in children and young adults with relapsed or refractory B-cell acute lymphoblastic leukemia (ALL). METHODS: We conducted a phase 2, single-cohort, 25-center, global study of tisagenlecleucel in pediatric and young adult patients with CD19+ relapsed or refractory B-cell ALL. The primary end point was the overall remission rate (the rate of complete remission or complete remission with incomplete hematologic recovery) within 3 months. RESULTS: For this planned analysis, 75 patients received an infusion of tisagenlecleucel and could be evaluated for efficacy. The overall remission rate within 3 months was 81%, with all patients who had a response to treatment found to be negative for minimal residual disease, as assessed by means of flow cytometry. The rates of event-free survival and overall survival were 73% (95% confidence interval [CI], 60 to 82) and 90% (95% CI, 81 to 95), respectively, at 6 months and 50% (95% CI, 35 to 64) and 76% (95% CI, 63 to 86) at 12 months. The median duration of remission was not reached. Persistence of tisagenlecleucel in the blood was observed for as long as 20 months. Grade 3 or 4 adverse events that were suspected to be related to tisagenlecleucel occurred in 73% of patients. The cytokine release syndrome occurred in 77% of patients, 48% of whom received tocilizumab. Neurologic events occurred in 40% of patients and were managed with supportive care, and no cerebral edema was reported. CONCLUSIONS: In this global study of CAR T-cell therapy, a single infusion of tisagenlecleucel provided durable remission with long-term persistence in pediatric and young adult patients with relapsed or refractory B-cell ALL, with transient high-grade toxic effects. (Funded by Novartis Pharmaceuticals; ClinicalTrials.gov number, NCT02435849 .).

Bone marrow transplant for X-linked protoporphyria with severe hepatic fibrosis.

XLP is an erythroid porphyria that results in variable cutaneous photosensitivity due to accumulation of protoporphyrin. The genetic defect in XLP is mutation of the gene ALAS2, resulting in gain of function for the erythroid enzyme 5-aminolevulinate synthase 2. Previous reports have shown that protoporphyrin-induced liver disease may also occur in XLP, occasionally severe enough to warrant liver transplantation; however, transplantation may be followed by injury to the graft due to continued presence of the underlying metabolic disorder in the bone marrow. We present a case of XLP with severe liver disease successfully treated with HPCT to avoid liver transplantation. The case also demonstrates the feasibility of reduced intensity transplant to provide engraftment sufficient for correction of porphyria and tolerability of reduced intensity conditioning containing TLI in the face of severe liver injury.

Cytotoxic T lymphocyte therapy with donor T cells prevents and treats adenovirus and Epstein-Barr virus infections after haploidentical and matched unrelated stem cell transplantation.

Viral infection or reactivation remains a major cause of morbidity and mortality after allogeneic stem cell transplantation. We now show that infusions of single cytotoxic T lymphocyte (CTL) lines (5 x 10(6)-1.35 x 10(8) cells/m(2)) with specificity for 2 commonly detected viruses, Epstein-Barr virus (EBV) and adenovirus, can be safely administered to pediatric transplantation recipients receiving partially human leukocyte antigen-matched and haploidentical stem cell grafts (n = 13), without inducing graft-versus-host disease. The EBV-specific component of the CTLs expanded in vivo and persisted for more than 12 weeks, but the adenovirus-specific component only expanded in vivo in the presence of concomitant adenoviral infection. Nevertheless, adenovirus-specific T cells could be detected for at least 8 weeks in peripheral blood, even in CTL recipients without viral infection, provided the adenovirus-specific component of their circulating lymphocytes was first expanded by exposure to adenoviral antigens ex vivo. After infusion, none of these 13 high-risk recipients developed EBV-associated lymphoproliferative disease, while 2 of the subjects had resolution of their adenoviral disease. Hence, bispecific CTLs containing both EBV- and adenovirus-specific T cells can safely reconstitute an antigen responsive "memory" population of CTLs after human leukocyte antigen-mismatched stem cell transplantation and may provide antiviral activity. This trial was registered at www.clinicaltrials.gov as #NCT00590083.

Successful treatment of stem cell graft failure in pediatric patients using a submyeloablative regimen of campath-1H and fludarabine.

Graft failure is a significant cause of morbidity and mortality after hematopoietic stem cell transplantation (HSCT). We used a nonmyeloablative conditioning regimen consisting of the lympho-depleting humanized CD52-antibody Campath-1H and fludarabine to rescue 12 consecutive children age 9 months to 17 years with engraftment failure after initial myeloablative HSCT. Primary diagnoses included lymphohematologic malignancies (n=6), severe combined immunodeficiency syndrome (SCID) (n=4), and metabolic diseases (n=2). The same stem cell donor was used as for the primary graft: mismatched family member (n=7), matched unrelated donor (n=4), or matched related donor (n=1). The patients received doses of CD34+ cells that did not significantly differ from those used in the initial, failed transplant. At a median follow-up of 51 months (range, 4 to 84 months), 6 of 6 patients with nonmalignant diseases and 4 of 6 patients with malignancy were alive. Two patients died, 1 patient from pulmonary toxicity and 1 from relapse, at 51 days and 8 months posttransplantation, respectively. All 12 patients initially achieved sustained neutrophil engraftment and complete donor chimerism by day 28. Six patients received donor lymphocyte infusion (DLI) after "rescue" therapy to maintain donor chimerism. At 6 months, 4 patients had complete donor cell engraftment, 4 had 15% to 89% stable donor chimerism, and 3 had developed secondary graft failure. This conditioning regimen was generally well tolerated; 4 of the 12 patients never became neutropenic, and 9 never became thrombocytopenic. Only 1 patient developed graft-versus-host disease (GVHD; grade 1), and none had chronic GVHD. Thus, the regimen that we describe can be used with minimal toxicity to effectively overcome graft failure after myeloablative HSCT in children.

Adenoviral infections in hematopoietic stem cell transplantation.

Adenoviruses are lytic DNA viruses that are ubiquitous in human communities. In total, 51 different serotypes with varying tissue tropisms have been identified. Adenovirus infections, although frequent, are rarely fatal in immunocompetent individuals who have potent innate and adaptive immunity. But in immunosuppressed individuals, adenoviruses are a significant cause of morbidity and mortality, with limited treatment options. In particular, pediatric recipients of allogeneic hematopoietic stem cell transplantation frequently develop infections early in the posttransplantation period. Because the endogenous recovery of adenovirus-specific T cells has proven important in controlling infection, we explore the potential of adoptive T-cell immunotherapy as a therapeutic strategy. We discuss the advantages and limitations of T-cell therapy for the prophylaxis and treatment of adenovirus infection posttransplantation.