Blinatumomab Therapy Is Associated with Favorable Outcomes after Allogeneic Hematopoietic Cell Transplantation in Pediatric Patients with B Cell Acute Lymphoblastic Leukemia.

Blinatumomab, a bispecific T cell engager that binds CD19 in leukemic cells and CD3 in cytotoxic T cells and leads to leukemic blast lysis, is often used in pediatric patients with relapsed/refractory (R/R) B cell acute lymphoblastic leukemia (B-ALL) prior to allogeneic hematopoietic cell transplantation (allo-HCT). Concerns about the potential risk of blinatumomab-related immune-mediated toxicities after allo-HCT have not been adequately addressed. These include graft-versus-host disease (GVHD), delayed engraftment, and graft failure or rejection. Pediatric-specific data reporting post-HCT outcomes of patients treated with blinatumomab are scarce and limited to small cohorts. We sought to investigate the clinical outcomes of pediatric patients with R/R B-ALL who received blinatumomab therapy pre-HCT, focusing on overall survival (OS), leukemia-free survival (LFS), cumulative incidence of relapse (CIR), and nonrelapse mortality (NRM), as well as the incidence of immune-mediated post-HCT complications including GVHD, delayed neutrophil or platelet engraftment, graft failure, and graft rejection. We also investigated blinatumomab's effects on B cell reconstitution based on achievement of i.v. immunoglobulin (IVIG) independence post-HCT. This single-center, retrospective study included patients with B-ALL receiving blinatumomab therapy before undergoing allo-HCT, with transplantation performed between 2016 and 2021 at our institution. Patients receiving blinatumomab for relapse after allo-HCT were excluded. Patients receiving chemotherapy alone before allo-HCT during the same period composed the control group. Seventy-two patients were included, 31 of whom received blinatumomab before allo-HCT. Survival estimates were obtained using the Kaplan-Meier method, and the log-rank test was used to analyze differences between groups. Categorical variables were compared between groups using the chi-square test or Fisher exact test, and continuous variables were compared using the Wilcoxon rank-sum test. Cumulative incidences were estimated using the competing risks method, and Gray's test was used to analyze differences between groups. A Cox proportional hazards regression model was used for univariate and multivariable analyses for OS. Landmark analysis was performed at the set time points of 30 days and 100 days post-allo-HCT. Most patients in the study cohort had high-risk relapsed B-ALL. Blinatumomab therapy induced minimal residual disease (MRD)-negative remissions in all patients, whereas 5 patients (12.2%) receiving chemotherapy alone had persistent MRD pre-allo-HCT. Time from the start of therapy to the date of allo-HCT was shorter for patients who received blinatumomab compared with those who received chemotherapy (P < .0001). Blinatumomab therapy was associated with greater LFS compared to chemotherapy alone (P = .049), but when limited to 1 year, LFS was not significantly different from control (P = .066). There appeared to be higher OS, lower CIR, and lower NRM in patients receiving blinatumomab compared to the control group; however, the differences were not significant. None of the variables assessed in multivariable analysis was associated with differences in OS. When compared to the controls, blinatumomab therapy did not result in a higher incidence of acute or chronic GVHD, delayed neutrophil or platelet engraftment, or graft failure or rejection. The time to IVIG infusion independence post-allo-HCT was similar in the 2 groups. This study supports the use of blinatumomab salvage therapy for R/R B-ALL before allo-HCT given its efficacy in inducing MRD-negative remissions and optimizing LFS, as well as its lack of association with an increased incidence of post-allo-HCT adverse immune-mediated toxicities. Larger, prospective studies are needed to confirm these findings and to investigate blinatumomab's effects in long-term post-allo-HCT events.

Hematopoietic stem cell transplantation for B-thalassemia major with alemtuzumab.

While matched related donor (MRD) allogeneic hematopoietic stem cell transplantation (HSCT) is a curative option for transfusion-dependent beta-thalassemia (TDT), the use of alternative sources has increased, resulting in the exploration of novel transplant-conditioning regimens to reduce the contribution of graft-versus-host disease (GVHD) and graft failure (GF) to transplant-related morbidity and mortality. Alemtuzumab is a CD52 monoclonal antibody that has been successfully incorporated into myeloablative conditioning regimens for other hematologic conditions, yet there have been limited studies regarding the use of alemtuzumab in HSCT for TDT. The purpose of this study was to evaluate engraftment, incidence of GVHD, and transplant related morbidity and mortality in patients with TDT who received alemtuzumab in addition to standard busulfan-based conditioning. The primary endpoint was severe GVHD-free, event-free survival (GEFS). Our cohort included 24 patients with a median age of 6.8 years (range 1.5-14.9). Eleven patients received a 10/10 MRD HSCT, eleven 10/10 unrelated donor (UD), and two mismatched UD. All patients achieved primary engraftment. For all patients, 5-year GEFS was 77.4% and 5-year overall survival (OS) was 91%. The 5-year cumulative incidence of GF (attributed to poor graft function) without loss of donor chimerism was 13.8% (95% CI: 4.5, 35.3). We report low rates of significant acute GVHD grade II-IV (12.5%) and chronic GVHD (4.4%). Younger age and MRD were associated with significantly improved GEFS, OS and EFS. Our results show that the use of alemtuzumab promotes stable engraftment, may reduce rates of severe GVHD, and results in acceptable GEFS, OS, and EFS.

Cord blood transplantation for nonmalignant disorders: early functional immunity and high survival.

There is no consensus on the best donor for children with nonmalignant disorders and immune deficiencies in the absence of a matched related donor (MRD). We evaluated the 2-year overall survival (OS) after umbilical cord blood transplantation (UCBT) in patients with nonmalignant disorders from 2009 to 2020 enrolled in a prospective clinical trial using either 5/6 or 6/6 UCB as the cell source. Patients receive a fully ablative busulfan, cyclophosphamide, and fludarabine without serotherapy. Fifty-five children were enrolled, median age 5 months (range, 1-111 months); primary immune deficiency (45), metabolic (5), hemophagocytic lymphohistiocytosis (1), and hematologic disorders (4). Twenty-six patients had persistent infections before transplant. Nineteen of them (34%) were 6/6 matched, and 36 (66%) were 5/6 human leukocyte antigen-matched. The OS at 2 years was 91% (95% cumulative incidence, 79-96), with a median follow-up of 4.3 years. The median time to neutrophil and platelet recovery were 17 days (range, 5-39 days) and 37 days (range, 20-92 days), respectively. All but one evaluable patient achieved full donor chimerism. The cumulative incidence of acute GVHD grades 2-4 on day 100 was 16% (n = 9). All patients with viral infections at the time of transplant cleared the infection at a median time of 54 days (range, 44-91 days). All evaluable patients underwent correction of their immune or metabolic defects. We conclude that in the absence of MRD, UCBT following myeloablative conditioning without serotherapy is an excellent curative option in young children with nonmalignant disorders. This trial has been registered at www.clinicaltrials.gov as NCT00950846.

Rituximab as adjunctive therapy to BEAM conditioning for autologous stem cell transplantation in Hodgkin lymphoma.

While high-dose chemotherapy followed by autologous stem cell transplantation (ASCT) leads to improved disease-free survival (DFS) for children and adults with relapsed/refractory Hodgkin lymphoma (HL), relapse remains the most frequent cause of mortality post-transplant. Rituximab has been successfully incorporated into regimens for other B-cell lymphomas, yet there have been limited studies of rituximab in HL patients. We hypothesized that adding rituximab to BEAM (carmustine, etoposide, cytarabine, melphalan) conditioning would reduce relapse risk in HL patients post-transplant. Here, we retrospectively review the outcomes of patients with relapsed/refractory HL who received rituximab in addition to BEAM. The primary outcome was DFS. Our cohort included 96 patients with a median age of 28 years (range, 6-76). Majority of patients (57%) were diagnosed with advanced (Stage III-IV) disease, and 62% were PET negative pre-transplant. DFS was 91.5% at 1 year [95% CI 86-98%], and 78% at 3 years [95% CI 68-88%]. NRM was 0% and 3.5% at 1-year [95% CI 0-3%] and 3-years [95% CI 0-8.5%], respectively. 25% of patients developed delayed neutropenia, with 7% requiring infection-related hospitalizations, and one death. We have demonstrated excellent outcomes for patients receiving rituximab with BEAM conditioning for relapsed/refractory HL. Future comparative studies are needed to better determine whether rituximab augments outcomes post-transplant.

Matched related hematopoietic cell transplant for sickle cell disease with alemtuzumab: the Texas Children's Hospital experience.

Serotherapeutic agents facilitate engraftment and prevent graft-versus-host disease (GVHD) following hematopoietic stem cell transplant. Anti-thymocyte globulin is generally added to conditioning chemotherapy for matched related donor transplant (MRD-HCT) for sickle cell disease (SCD). Alemtuzumab, however, is appealing due to its broad lymphocyte killing that may achieve very low rejection and GVHD rates. To assess the impact of alemtuzumab in MRD-HCT for SCD, we retrospectively reviewed transplant-related outcomes and markers of immunity in 38 consecutive patients at Texas Children's Hospital having received myeloablative conditioning with alemtuzumab. Median follow-up was 4.8 years (range: 0.2-17). All patients engrafted. Donor chimerism was mixed in 47.1% of patients at ≥2-years. Donor chimerism <50% was uncommon (n = 2). One patient with low myeloid chimerism (19%) had sickle-related hemolysis at 10-years. Incidence of acute GVHD grade II-IV (5.3%) and extensive chronic GVHD (2.8%) was very low. Five-year event-free survival (EFS) and composite chronic GVHD-EFS were excellent at 94.7% (95% CI: 80.3, 98.6) and 89.2% (95% CI: 73.7, 95.8), respectively. Infections did not contribute to mortality although cytomegalovirus reactivation occurred commonly in the first 3 months after transplant. Our data suggest potential for alemtuzumab in myeloablative transplant for children with SCD although further evaluation in older patients and with unrelated donors is warranted.

Hematopoietic Cell Transplantation in Patients With Primary Immune Regulatory Disorders (PIRD): A Primary Immune Deficiency Treatment Consortium (PIDTC) Survey.

Primary Immune Regulatory Disorders (PIRD) are an expanding group of diseases caused by gene defects in several different immune pathways, such as regulatory T cell function. Patients with PIRD develop clinical manifestations associated with diminished and exaggerated immune responses. Management of these patients is complicated; oftentimes immunosuppressive therapies are insufficient, and patients may require hematopoietic cell transplant (HCT) for treatment. Analysis of HCT data in PIRD patients have previously focused on a single gene defect. This study surveyed transplanted patients with a phenotypic clinical picture consistent with PIRD treated in 33 Primary Immune Deficiency Treatment Consortium centers and European centers. Our data showed that PIRD patients often had immunodeficient and autoimmune features affecting multiple organ systems. Transplantation resulted in resolution of disease manifestations in more than half of the patients with an overall 5-years survival of 67%. This study, the first to encompass disorders across the PIRD spectrum, highlights the need for further research in PIRD management.

Tailoring the Seebeck Coefficient of Spray-Coated Poly(3,4-ethylenedioxythiophene): Poly(styrenesulfonate) Films with Nitrogen Doped Multiwalled Carbon Nanotubes.

The thermoelectric properties of flexible thin films fabricated from two commercial poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) formulations filled with multiwalled carbon nanotubes (MWCNT) and nitrogen-doped MWCNT (N-MWCNT) were investigated. A simple spray-coating method for the fabrication of such flexible films on a polyethylene terephthalate substrate was developed. While increasing the MWCNT concentration had little effect on the thermoelectric properties, increasing the N-MWCNT concentration resulted in the emergence of an overall n-type semiconducting behavior and, thereby, tailoring the Seebeck coefficient of the composite films from p-type to n-type was shown. The Seebeck coefficient of the two PEDOT:PSS formulation films was inverted from 4.1 to -13.3 µV/K and from 12.5 to -10.9 µV/K respectively, with increasing N-MWCNT concentration from 0 to 95 wt.%. The importance of these results for future work stems from the possibility of tailoring the behavior of a typical p-type polymer such as PEDOT:PSS and the effect that the polymer conductive grade has on the switching concentration.

SCID genotype and 6-month posttransplant CD4 count predict survival and immune recovery.

The Primary Immune Deficiency Treatment Consortium (PIDTC) performed a retrospective analysis of 662 patients with severe combined immunodeficiency (SCID) who received a hematopoietic cell transplantation (HCT) as first-line treatment between 1982 and 2012 in 33 North American institutions. Overall survival was higher after HCT from matched-sibling donors (MSDs). Among recipients of non-MSD HCT, multivariate analysis showed that the SCID genotype strongly influenced survival and immune reconstitution. Overall survival was similar for patients with RAG, IL2RG, or JAK3 defects and was significantly better compared with patients with ADA or DCLRE1C mutations. Patients with RAG or DCLRE1C mutations had poorer immune reconstitution than other genotypes. Although survival did not correlate with the type of conditioning regimen, recipients of reduced-intensity or myeloablative conditioning had a lower incidence of treatment failure and better T- and B-cell reconstitution, but a higher risk for graft-versus-host disease, compared with those receiving no conditioning or immunosuppression only. Infection-free status and younger age at HCT were associated with improved survival. Typical SCID, leaky SCID, and Omenn syndrome had similar outcomes. Landmark analysis identified CD4+ and CD4+CD45RA+ cell counts at 6 and 12 months post-HCT as biomarkers predictive of overall survival and long-term T-cell reconstitution. Our data emphasize the need for patient-tailored treatment strategies depending upon the underlying SCID genotype. The prognostic significance of CD4+ cell counts as early as 6 months after HCT emphasizes the importance of close follow-up of immune reconstitution to identify patients who may need additional intervention to prevent poor long-term outcome.

Cytomegalovirus Retinitis in Pediatric Stem Cell Transplants: Report of a Recent Cluster and the Development of a Screening Protocol.

PURPOSE: The incidence of cytomegalovirus (CMV) retinitis in the pediatric allogeneic hematopoietic stem cell transplant (HSCT) population is unknown. We report a cluster of 5 pediatric patients with CMV retinitis diagnosed in a 12-month period and compare this to the rate of CMV viremia and retinitis in the 4 years prior. Presented is the ophthalmic screening protocol developed in response to this experience. DESIGN: Retrospective cross-sectional study. METHODS: A retrospective chart review was performed on patients at Children's Hospital of Colorado (CHCO) who received allogeneic HSCT between January 2010 and December 2014. Fisher exact test was used to compare the proportion of CMV viremia and CMV retinitis in patients transplanted between January 2010 and December 2013 with those transplanted in 2014. RESULTS: A total of 101 patients underwent allogeneic HSCT from January 2010 to December 2013; 32 (32%) tested positive for CMV viremia. No cases of CMV retinitis were identified. From January 2014 to December 2014, 28 patients underwent allogeneic HSCT; 13 patients (46%) had CMV viremia, not a statistically significant increase (P = .18). There were 5 cases of CMV retinitis diagnosed in those transplanted in 2014, a statistically significant increase compared with those transplanted in 2010-2013 (P = .0004). A multidisciplinary team was formed to review the literature and an ophthalmic screening protocol was developed. CONCLUSION: Our recent cluster of CMV retinitis in pediatric allogeneic HSCT patients may suggest a rise in incidence of CMV retinitis. We propose an ophthalmic screening protocol to diagnose retinitis in pediatric HSCT patients in the early, often asymptomatic stage.

Spray-Coated Multiwalled Carbon Nanotube Composite Electrodes for Thermal Energy Scavenging Electrochemical Cells.

Spray-coated multiwalled carbon nanotube/poly(vinylidene fluoride) (MWCNT/PVDF) composite electrodes, scCNTs, with varying CNT compositions (2 to 70 wt %) are presented for use in a simple thermal energy-scavenging cell (thermocell) based on the ferro/ferricyanide redox couple. Their utility for direct thermal-to-electrical energy conversion is explored at various temperature differentials and cell orientations. Performance is compared to that of buckypaper, a 100% CNT sheet material used as a benchmark electrode in thermocell research. The 30 to 70 wt % scCNT composites give the highest power output by electrode area-seven times greater than buckypaper at ΔT = 50 °C. CNT utilization is drastically enhanced in our electrodes, reaching 1 W gCNT(-1) compared to 0.036 W gCNT(-1) for buckypaper. Superior performance of our spray-coated electrodes is attributed to both wettability with better use of a large portion of electrochemically active CNTs and minimization of ohmic and thermal contact resistances. Even composites with as low as 2 wt % CNTs are still competitive with prior art. The MWCNT/PVDF composites developed herein are inexpensive, scalable, and serve a general need for CNT electrode optimization in next-generation devices.

Photoinduced p- to n-type Switching in Thermoelectric Polymer-Carbon Nanotube Composites.

UV-induced switching from p- to n-type character is demonstrated during deposition of carbon-nanotube-conjugated polymer composites. This opens the possibility to photopattern n-type regions within an otherwise p-type film, which has a potential for complementary circuitry or, as shown here, thermoelectric generators made from a single solution.

Continuous Processing of Multi-Walled Carbon Nanotube-Studded Carbon Fiber Tapes for Enhanced Through-Thickness Thermal Diffusivity Composites.

Carbon fiber reinforced polymer (CFRP) composites offer advantages over traditional metallic structures, particularly specific strength and stiffness, but at much reduced thermal conductivity. Moreover, fiber-to-fiber heat conduction in the composite transverse directions is significantly lower. When these structures contain electronics (heat generators), shortfalls in heat transport can be problematic. Here we report the achievement of a continuous, reel-to-reel process for growing short multiwalled carbon nanotubes (MWCNT) on the surfaces of spread-tow carbon fiber tapes. These tapes were subsequently prepregged with an epoxy matrix, and laid up into multi-ply laminate panels, cured and tested for through-thickness thermal diffusivity. The results showed up to a 57% increase in through thickness thermal diffusivity compared to the baseline composite with no MWCNT.

In Vivo T Cell Depletion with Myeloablative Regimens on Outcomes after Cord Blood Transplantation for Acute Lymphoblastic Leukemia in Children.

The inclusion of antithymocyte globulin (ATG) in cord blood transplantation is controversial. We evaluated outcomes according to ATG inclusion in 297 children and adolescents with acute lymphoblastic leukemia (ALL) who received myeloablative total body irradiation-based conditioning and either single-unit (74%) or double-unit (26%) grafts. Ninety-two patients (31%) received ATG and 205 (69%) did not. ATG recipients were more likely to be cytomegalovirus seronegative. The incidences of day 100 grades II to IV acute graft-versus-host disease (GVHD; 30% versus 54%, P = .0002) and chronic GVHD (22% versus 43%, P = .0008) were lower with ATG compared with non-ATG regimens. However, day 100 grades III to IV acute GVHD was comparable (11% versus 17%, P = .15). The 3-year incidences of transplant-related mortality (16% versus 17%, P = .98), relapse (17% versus 27%, P = .12), and leukemia-free survival (66% versus 55%, P = .23) in ATG and non-ATG recipients were similar. There were no differences in viral reactivation between treatment groups (60% versus 58%, P = .83). Therefore, the data suggest that incorporation of ATG with myeloablative conditioning regimens may be useful in reducing the risk of acute and chronic GVHD without any deleterious effect on transplant-related mortality, relapse, or leukemia-free survival in children and adolescents with ALL.

Safety and clinical efficacy of rapidly-generated trivirus-directed T cells as treatment for adenovirus, EBV, and CMV infections after allogeneic hematopoietic stem cell transplant.

Adoptive transfer of virus-specific T cells can prevent and treat serious infections with Epstein-Barr virus (EBV), cytomegalovirus (CMV), and adenovirus (Adv) after allogeneic hematopoietic stem cell transplant. It has, however, proved difficult to make this approach widely available since infectious virus and viral vectors are required for T cell activation, followed by an intensive and prolonged culture period extending over several months. We now show that T cells targeting a range of viral antigens derived from EBV, CMV, and Adv can be reproducibly generated in a single culture over a 2-3-week period, using methods that exclude all viral components and employ a much-simplified culture technology. When administered to recipients of haploidentical (n = 5), matched unrelated (n = 3), mismatched unrelated (n = 1) or matched related (n = 1) transplants with active CMV (n = 3), Adv (n = 1), EBV (n = 2), EBV+Adv (n = 2) or CMV+Adv (n = 2) infections, the cells produced complete virological responses in 80%, including all patients with dual infections. In each case, a decrease in viral load correlated with an increase in the frequency of T cells directed against the infecting virus(es); both immediate and delayed toxicities were absent. This approach should increase both the feasibility and applicability of T cell therapy. The trial was registered at www.clinicaltrials.gov as NCT01070797.

Impact of immune modulation with in vivo T-cell depletion and myleoablative total body irradiation conditioning on outcomes after unrelated donor transplantation for childhood acute lymphoblastic leukemia.

To determine whether in vivo T-cell depletion, which lowers GVHD, abrogates the antileukemic benefits of myeloablative total body irradiation-based conditioning and unrelated donor transplantation, in the present study, we analyzed 715 children with acute lymphoblastic leukemia. Patients were grouped for analysis according to whether conditioning included antithymocyte globulin (ATG; n = 191) or alemtuzumab (n = 132) and no in vivo T-cell depletion (n = 392). The median follow-up time was 3.5 years for the ATG group and 5 years for the alemtuzumab and T cell-replete groups. Using Cox regression analysis, we compared transplantation outcomes between groups. Compared with no T-cell depletion, grade 2-4 acute and chronic GVHD rates were significantly lower after in vivo T-cell depletion with ATG (relative risk [RR] = 0.66; P = .005 and RR = 0.55; P < .0001, respectively) or alemtuzumab (RR = 0.09; P < .003 and RR = 0.21; P < .0001, respectively). Despite lower GVHD rates after in vivo T-cell depletion, nonrelapse mortality, relapse, overall survival, and leukemia-free survival (LFS) did not differ significantly among the treatment groups. The 3-year probabilities of LFS after ATG-containing, alemtuzumab-containing, and T cell-replete transplantations were 43%, 49%, and 46%, respectively. These data suggest that in vivo T-cell depletion lowers GVHD without compromising LFS among children with acute lymphoblastic leukemia who are undergoing unrelated donor transplantation with myeloablative total body irradiation-based regimens.

Enhanced tumor trafficking of GD2 chimeric antigen receptor T cells by expression of the chemokine receptor CCR2b.

For adoptive T-cell therapy to be effective against solid tumors, tumor-specific T cells must be able to migrate to the tumor site. One requirement for efficient migration is that the effector cells express chemokine receptors that match the chemokines produced either by tumor or tumor-associated cells. In this study, we investigated whether the tumor trafficking of activated T cells (ATCs) bearing a chimeric antigen receptor specific for the tumor antigen GD2 (GD2-CAR) could be enhanced by forced coexpression of the chemokine receptor CCR2b, as this receptor directs migration toward CCL2, a chemokine produced by many tumors, including neuroblastoma. Neuroblastoma cell lines (SK-N-SH and SK-N-AS) and primary tumor cells isolated from 6 patients all secreted high levels of CCL2, but GD2-CAR transduced ATCs lacked expression of CCR2 (<5%) and migrated poorly to recombinant CCL2 or tumor supernatants. After retroviral transduction, however, ATCs expressed high levels of CCR2b (>60%) and migrated well in vitro. We expressed firefly luciferase in CCR2b-expressing ATCs and observed improved homing (>10-fold) to CCL2-secreting neuroblastoma compared with CCR2-negative ATCs. As a result, ATCs co-modified with both CCR2b and GD2-CAR had greater antitumor activity in vivo.