Comparative genomic expression signatures of signal transduction pathways and targets in paediatric Burkitt lymphoma: a Children's Oncology Group report.

Burkitt lymphoma (BL) is the most common histological subtype of non-Hodgkin lymphoma (NHL) in children and adolescents. Through the introduction of short intensive multi-agent chemoimmunotherapy, survival has improved significantly over the past 30 years. However, this successful approach is limited by significant chemotherapy-induced acute toxicity and risk of developing resistant disease, demonstrating the need to identify less toxic and targeted therapies. We analysed the comparative genomic signature and targetable signalling pathways in paediatric BL (PEBL) samples from the Children's Oncology Group study (ANHL01P1) by genomic profiling and selected genes were confirmed by quantitative real time polymerase chain reaction. These results were compared to PEBL samples from public databases and utilised the Gene Expression Omnibus (GEO) Series (GSE) 10172 and 4475 (n = 16), and 4732 (n = 15). Three hundred and seventy-six genes (approximately 25%) were similarly expressed among three PEBL sample groups. Several target genes in Toll-like receptor signalling, JAK-STAT signalling and MAPK signalling were significantly overexpressed in PEBL. In addition, several tyrosine kinases, including Bruton tyrosine kinase, protein tyrosine phosphatase and histone deacetylase inhibitor were highly expressed in PEBL. These pre-clinical results suggest that specific signal transduction pathways are overly expressed in PEBL and several pathways could serve as potential future therapeutic targets.

A Phase I Study of Reduced-Intensity Conditioning and Allogeneic Stem Cell Transplantation Followed by Dose Escalation of Targeted Consolidation Immunotherapy with Gemtuzumab Ozogamicin in Children and Adolescents with CD33+ Acute Myeloid Leukemia.

Myeloablative conditioning and allogeneic hematopoietic stem cell transplant (alloHSCT) in children with acute myeloid leukemia (AML) in first complete remission (CR1) may be associated with significant acute toxicity and late effects. Reduced-intensity conditioning (RIC) and alloHSCT in children is safe, feasible, and may be associated with less adverse effects. Gemtuzumab ozogamicin (GO) induces a response in 30% of patients with CD33+ relapsed/refractory AML. The dose of GO is significantly lower when combined with chemotherapy. We examined the feasibility and toxicity of RIC alloHSCT followed by GO targeted immunotherapy in children with CD33+ AML in CR1/CR2. Conditioning consisted of fludarabine 30 mg/m2 × 6 days, busulfan 3.2 to 4 mg/kg × 2 days ± rabbit antithymocyte globulin 2 mg/kg × 4 days followed by alloHSCT from matched related/unrelated donors. GO was administered ≥60 days after alloHSCT in 2 doses (8 weeks apart), following a dose-escalation design (4.5, 6, 7.5, and 9 mg/m2). Fourteen patients with average risk AML received RIC alloHSCT and post-GO consolidation: median age 13.5 years at transplant (range, 1 to 21), male-to-female 8:6, and disease status at alloHSCT 11 CR1 and 3 CR2. Eleven patients received alloHSCT from 5-6/6 HLA-matched family donors: 8 received peripheral blood stem cells, 2 received bone marrow, and 1 received related cord blood transplantation. Three patients received an unrelated allograft (two 4-5/6 and one 9/10) from unrelated cord blood unit and bone marrow, respectively. Neutrophil and platelet engraftment was observed in all assessable patients (100%), achieved at median 15.5 days (range, 7 to 31) and 21 days (range, 10 to 52), respectively. Three patients received GO at dose level 1 (4.5 mg/m2 per dose), 5 at dose level 2 (6 mg/m2 per dose), 3 at dose level 3 (7.5 mg/m2 per dose), and 3 at dose level 4 (9 mg/m2 per dose). Three of 14 patients received only 1 dose of GO after alloHSCT. One patient experienced grade III transaminitis, which resolved; no grade IV transaminitis, no grade III/IV hyperbilirubinemia, or sinusoidal obstructive syndrome were observed. The second dose of GO was given at median of 143 days (range, 120 to 209) after alloHSCT. Probability of grades II to IV acute and chronic graft-versus-host disease were 21% and 33.5%, respectively. Probability of overall survival after RIC alloHSCT and GO consolidation at 1 and 5 years was 78% and 61%, respectively. Probability of 5-year event-free survival after RIC alloHSCT and GO consolidation in patients in CR1 was 78%. No dose-limiting toxicities probably or directly related to GO were observed in this cohort. This preliminary data demonstrate that RIC followed by alloHSCT and consolidation with GO appears to be safe in children and adolescents with CD33+ AML in CR1/CR2. A phase II trial is currently underway investigating this approach with a GO dose of 9 mg/m2 per dose.

Rescue of the mucocutaneous manifestations by human cord blood derived nonhematopoietic stem cells in a mouse model of recessive dystrophic epidermolysis bullosa.

Recessive dystrophic epidermolysis bullosa (RDEB) is a severe skin blistering disease caused by mutations in COL7A1-encoding type VII collagen (C7). Currently, there is no curative therapy for patients with RDEB. Our previous studies demonstrated that human umbilical cord blood (HUCB) derived unrestricted somatic stem cells (USSCs) express C7 and facilitate wound healing in a murine wounding model. The primary objective of this study is to investigate the therapeutic functions of USSCs in the C7 null (Col7a1(-/-) ) C57BL6/J mice, a murine model of RDEB. We demonstrated that intrahepatic administration of USSCs significantly improved the blistering phenotype and enhanced the life span in the recipients. The injected USSCs trafficked to the sites of blistering and were incorporated in short-term in the recipients' skin and gastrointestinal tract. Consistent with an overall histological improvement in the epidermal-dermal adherence following USSC treatment, the expression of C7 at the basement membrane zone was detected and the previously disorganized integrin α6 distribution was normalized. We also demonstrated that USSCs treatment induced an infiltration of macrophages with a regenerative "M2" phenotype. Our data suggest that HUCB-derived USSCs improved the RDEB phenotype through multiple mechanisms. This study has warranted future clinical investigation of USSCs as a novel and universal allogeneic stem cell donor source in selected patients with RDEB.

Obinutuzumab (GA101) compared to rituximab significantly enhances cell death and antibody-dependent cytotoxicity and improves overall survival against CD20(+) rituximab-sensitive/-resistant Burkitt lymphoma (BL) and precursor B-acute lymphoblastic leukaemia (pre-B-ALL): potential targeted therapy in patients with poor risk CD20(+) BL and pre-B-ALL.

Obinutuzumab is a novel glycoengineered Type-II CD20 monoclonal antibody. CD20 is expressed in approximately 100% of children and adolescents with Burkitt lymphoma (BL) and 40% with precursor B-cell acute lymphoblastic leukaemia (pre-B-ALL). We evaluated the anti-tumour activity of obinutuzumab versus rituximab against rituximab-resistant (Raji 4RH) and -sensitive (Raji) BL and pre-B-ALL (U698-M) cells in vitro and in human BL or Pre-B-ALL xenografted mice. We demonstrated that obinutuzumab compared to rituximab significantly enhanced cell death against Raji 35·6 ± 3·1% vs. 25·1 ± 2·0%, (P = 0·001), Raji4RH 19·7 ± 2·2% vs. 7·9 ± 1·5% (P = 0·001) and U-698-M 47·3 ± 4·9% vs. 23·2 ± 0·5% (P = 0·001), respectively. Obinutuzumab versus rituximab also induced a significant increase in antibody-dependent cellular cytotoxicity (ADCC) with K562-IL15-41BBL expanded NK cells against Raji 73·8 ± 8·1% vs. 56·81 ± 4·6% (P = 0·001), Raji-4RH 40·0 ± 1·6% vs. 0·5 ± 1·1% (P = 0·001) and U-698-M 70·0 ± 1·6% vs. 45·5 ± 0·1% (P = 0·001), respectively. Overall survival in tumour xenografted mice receiving 30 mg/kg of obinutuzumab was significantly increased when compared to those receiving 30 mg/kg of rituximab in BL; Raji (P = 0·05), Raji4RH (P = 0·02) and U698-M (P = 0·03), respectively. These preclinical data suggest obinutuzumab is significantly superior to rituximab in inducing cell death, ADCC and against rituximab-sensitive/-resistant BL and pre-B-ALL xenografted mice. Taken together, these preclinical results provide evidence to suggest that future investigation of obinutuzumab is warranted in patients with relapsed/refractory CD20(+) BL and/or pre-B-ALL.

A comparison of bronchoalveolar lavage versus lung biopsy in pediatric recipients after stem cell transplantation.

Bronchoalveolar lavage (BAL) has been a useful initial diagnostic tool in the evaluation of pulmonary complications after hematopoietic stem cell transplantation (HSCT); however, the diagnostic sensitivity, prevalence, and outcome after BAL versus lung biopsy (LB) in pediatric HSCT patients remains to be determined. We reviewed 193 pediatric HSCT recipients who underwent a total of 235 HSCTs. Sixty-five patients (34%) underwent a total of 101 BALs for fever, respiratory distress, and/or pulmonary infiltrates on chest radiograph and/or computed tomography scan. The 1-year probability of undergoing BAL was 43.0% after allogeneic stem cell transplantation (alloSCT) and 8.5% after autologous stem cell transplantation (autoSCT) (P = .001). Sixteen of the 193 patients (8%) patients underwent 19 LBs. The probability of undergoing LB at 1 year after HSCT was 9.3%. No grade III or IV adverse events related to either procedure were observed. Of the 101 BALs performed, 40% (n = 40) were diagnostic, with a majority revealing a bacterial pathogen. Among the 19 LBs performed, 94% identified an etiology. In multivariate analysis, myeloablative conditioning alloSCT conferred the highest risk of requiring a BAL (hazard ratio [HR],8.5; P = .0002). The probability of 2-year overall survival was 20.2% in patients who underwent BAL, 17.5% for patients who underwent biopsy, and 67.4% for patients who had neither procedure. In multivariate analysis, only the requirement of a BAL was independently associated with an increased risk of mortality (HR, 2.96; P < .0001). In summary, in this cohort of pediatric HSCT recipients, BAL and LB were used in approximately 35% and 8% of pediatric HSCTs with diagnostic yields of approximately 40% and 94%, respectively, and were both associated with poor long-term outcomes.

Upregulation of NKG2D ligands in acute lymphoblastic leukemia and non-Hodgkin lymphoma cells by romidepsin and enhanced in vitro and in vivo natural killer cell cytotoxicity.

BACKGROUND AIMS: There is a critical need to prevent and/or treat hematological relapse after allogeneic hematopoietic stem cell transplantation. The activating NKG2D receptor expressed on natural killer (NK) cells, when engaged by its corresponding ligands (MIC A/B), activates NK cells to become cytotoxic against malignant cells. METHODS: We incubated acute lymphoblastic leukemia and non-Hodgkin lymphoma cells for 24 h with 10 ng/mL of romidepsin. Flow cytometry was performed to demonstrate changes in surface expression of NKG2D ligands MIC A/B. In vitro and in vivo cytotoxicity was measured by means of modified Europium assay, and non-obese diabetic/severe combined immunodeficiency mice were xenografted with RS 4:11 cells. RESULTS: We demonstrated an approximately 50, 200, 1300 and 180-fold increase in the number of cells positive for the surface expression of MIC A/B in RS 4:11 (P < 0.001), REH (P < 0.001), Ramos (P < 0.001) and Jurkat cells (P < 0.001), respectively. We further demonstrated a significant increase in NK cell-mediated in vitro cytotoxicity against RS 4:11 (P < 0.004), Ramos (P < 0.05), Jurkat (P < 0.001) and REH cells (P < 0.01), respectively. Romidepsin-mediated NK cytotoxicity was blocked by pre-incubating NK cells with anti-NKG2D-Fc in RS 4:11 (P < 0.03) and Ramos cells (P < 0.01), respectively. Finally, non-obese diabetic/severe combined immunodeficiency mice xenografted with RS 4:11 cells had a significant increase in survival (P < 0.02) in mice treated with romidepsin and interleukin-2-activated NK cells compared with each of these other treatment groups. CONCLUSIONS: Romidepsin significantly enhanced in vitro and in vivo NK cell cytotoxicity mediated in part by increased MIC A/B expression on malignant cells. This translational approach of the use of romidepsin and interleukin-2-activated NK cells should be considered in patients with relapsed/refractory leukemia or lymphoma.

Pilot trial of risk-adapted cyclophosphamide intensity based conditioning and HLA matched sibling and unrelated cord blood stem cell transplantation in newly diagnosed pediatric and adolescent recipients with acquired severe aplastic anemia.

BACKGROUND: Cyclophosphamide-based conditioning regimens and allogeneic hematopoietic stem cell transplantation (AlloHSCT) from matched related donors (MRD) has resulted in the highest survival rates in children and adolescents with acquired severe aplastic anemia (SAA). Time to transplant has consistently been associated with decreased overall survival. Reduced toxicity conditioning and AlloHSCT has been used successfully in other pediatric non-malignant diseases. PROCEDURE: We piloted a risk-adapted AlloHSCT approach, using fludarabine and anti-thymocyte globulin based conditioning with high (200 mg/kg) and low (60 mg/kg) dose cyclophosphamide as upfront treatment in newly diagnosed pediatric patients with acquired SAA incorporating alternative donor sources, including cord blood. Average risk for non-engraftment patients with <10 transfusions received low dose cyclophosphamide (60 mg/kg); High Risk, those with ≥10 transfusions received conditioning regimen with higher intensity cyclophosphamide (200 mg/kg). RESULTS: Seventeen patients were enrolled and underwent AlloHSCT including 12 males and 5 females with mean age of 8 years (range 3-16), and median follow-up time of 39 months (range 1-135). Donor sources included MRD BM (6/6 [n = 9], 5/6 [n = 2]) and unrelated CB (5/6 [n = 4], 4/6 [n = 2]). Five year OS was 67.6% (37.9-85.4). Three secondary graft failures (17.6%) occurred in the low dose cyclophosphamide arm. CONCLUSIONS: Upfront treatment with risk-adapted cyclophosphamide conditioning AlloSCT is well tolerated for the management of newly diagnosed pediatric and adolescent patients with acquired SAA. However, the increased risk of graft rejection in the lower dose arm warrants additional research regarding the optimal intensity of cyclophosphamide-based conditioning regimen to reduce toxicity without increasing graft failure.

Risk Factors Associated with Survival Following Ganciclovir Prophylaxis through Day +100 in Cytomegalovirus At-Risk Pediatric Allogeneic Stem Cell Transplantation Recipients: Development of Cytomegalovirus Viremia Associated with Significantly Decreased 1-Year Survival.

Cytomegalovirus (CMV) reactivation is a major cause of morbidity and nonrelapse mortality (NRM) in pediatric allogeneic stem cell transplantation (alloSCT) recipients. Approximately 80% of CMV seropositive alloHCT recipients will experience CMV reactivation without prophylaxis. The impacts of ganciclovir prophylaxis and subsequent CMV viremia on 1-year survival and 1-year NRM are unknown. The primary objective of this study was to determine the effect of CMV viremia on the probability of 1-year survival and 1-year NRM in pediatric alloSCT recipients receiving 100 days of ganciclovir prophylaxis. The secondary objective was to determine the effect of other risk factors on 1-year survival and 1-year NRM. All patients age 0 to 26 years who underwent alloSCT between June 2011 and May 2020 and received ganciclovir prophylaxis for 100 days at Westchester Medical Center, an academic medical center, were analyzed. Ganciclovir was administered to at-risk alloSCT recipients (donor and or recipient CMV+ serostatus) as 5 mg/kg every 12 hours from the first day of conditioning through day -1 (recipient CMV+ only) followed by 6 mg/kg every 24 hours on Monday through Friday beginning on the day of an absolute neutrophil count >750/mm3 and continuing through day +100. National Cancer Institute Common Terminology Criteria for Adverse Events 5.0 criteria were used to grade toxicity. NRM was analyzed using competing survival analysis with relapse death as a competing event. The log-rank and Gray tests were performed to compare the 1-year survival probabilities and NRM cumulative incidence between patients who experienced CMV viremia post-alloSCT and those who did not. Univariate Cox regression analysis was performed for the following risk factors: CMV viremia, donor source, sex, malignant disease, disease risk index, conditioning intensity, receipt of rabbit antithymocyte globulin (rATG)/alemtuzumab, graft-versus-host disease (GVHD) prophylaxis, CMV donor/recipient serostatus, grade II-IV acute GVHD, and grade 3/4 neutropenia necessitating discontinuation of ganciclovir, treating the last 3 factors as time-dependent covariates. Those with P values < .2 were included in the multivariate Cox regression analysis. Eighty-four alloSCT recipients (41 males, 43 females; median age, 10.8 years [range, .4 to 24.4 years]) were analyzed. Multivariate analysis showed significantly lower 1-year survival and significantly higher 1-year NRM in patients who developed CMV viremia compared to those who did not (P = .0036). No other risk factors were significantly associated with 1-year survival or 1-year NRM. One-year survival was significantly decreased and 1-year NRM was significantly increased in pediatric alloSCT recipients who developed CMV viremia following ganciclovir prophylaxis. No other risk factors were found to be associated with 1-year survival or 1-year NRM. Alternative CMV prophylaxis regimens that reduce CMV viremia should be investigated in pediatric alloSCT recipients at risk for CMV infection.

Neurocognitive outcome in children with sickle cell disease after myeloimmunoablative conditioning and haploidentical hematopoietic stem cell transplantation: a non-randomized clinical trial.

Background: Due to the risk of cerebral vascular injury, children and adolescents with high-risk sickle cell disease (SCD) experience neurocognitive decline over time. Haploidentical stem cell transplantation (HISCT) from human leukocyte antigen-matched sibling donors may slow or stop progression of neurocognitive changes. Objectives: The study is to determine if HISCT can ameliorate SCD-associated neurocognitive changes and prevent neurocognitive progression, determine which specific areas of neurocognitive functioning are particularly vulnerable to SCD, and determine if there are age-related differences in neurocognitive functioning over time. Methods: We performed neurocognitive and neuroimaging in SCD recipients following HISCT. Children and adolescents with high-risk SCD who received parental HISCT utilizing CD34+ enrichment and mononuclear cell (T-cell) addback following myeloimmunoablative conditioning received cognitive evaluations and neuroimaging at three time points: pre-transplant, 1 and 2 years post-transplant. Results: Nineteen participants (13.1 ± 1.2 years [3.3-20.0]) received HISCT. At 2 years post-transplant, neuroimaging and cognitive function were stable. Regarding age-related differences pre-transplantation, older children (≥13 years) had already experienced significant decreases in language functioning (p < 0.023), verbal intelligence quotient (p < 0.05), non-verbal intelligence quotient (p < 0.006), and processing speed (p < 0.05), but normalized post-HISCT in all categories. Conclusion: Thus, HISCT has the potential to ameliorate SCD-associated neurocognitive changes and prevent neurocognitive progression. Further studies are required to determine if neurocognitive performance remains stable beyond 2 years post-HISCT.Clinical trial registration: The study was conducted under an investigator IND (14359) (MSC) and registered at clinicaltrials.gov (NCT01461837).

A Phase I study of gemtuzumab ozogamicin (GO) in combination with busulfan and cyclophosphamide (Bu/Cy) and allogeneic stem cell transplantation in children with poor-risk CD33+ AML: a new targeted immunochemotherapy myeloablative conditioning (MAC) regimen.

Children with high-risk acute myelogenous leukemia (AML) (induction failure [IF], refractory relapse [RR], third complete remission [CR3]) have dismal outcomes. Over 80% of AML patients express CD33, a target of gemtuzumab ozogamicin (GO). GO is an active drug in childhood AML but has not been studied in a myeloablative conditioning regimen. We sought to determine the safety of GO in combination with busulfan/cyclophosphamide (Bu/Cy) conditioning before allogeneic hematopoietic stem cell transplantation (alloSCT). GO was administered on day -14 at doses of 3.0, 4.5, 6.0, and 7.5 mg/m(2), busulfan on days -7, -6, -5, -4 (12.8-16.0 mg/kg), and cyclophosphamide on days -3 and -2 (60 mg/kg/day). GVHD prophylaxis consisted of tacrolimus and mycophenolate mofetil. We enrolled 12 patients: 8 IF, 3 RR, 1 CR3; median age: 3 years (1-17); median follow-up: 1379 days (939-2305). Nine received umbilical cord blood (UCB), 2 matched unrelated donors (MUDs) and 1 HLA-matched sibling donor: 3 patients each at GO doses of 3.0, 4.5, 6.0, or 7.5 mg/m(2). No dose-limiting toxicities secondary to GO were observed. Day 100 treatment-related mortality (TRM) was 0%. Myeloid and platelet engraftment was observed in 92% and 75% of patients at median day 22 (12-40) and 42 (21-164), respectively. Median day +30 donor chimerism was 99% (85%-100%). The probability of grade II-IV acute graft-versus-host disease (aGVHD) was 42% and chronic GVHD (cGVHD) was 28%. One-year overall survival (OS) and event-free survival (EFS) was 50% (95% confidence interval [CI], 20.8-73.6). GO combined with Bu/Cy regimen followed by alloSCT is well tolerated in children with poor-risk AML. GO at 7.5 mg/m(2) in combination with Bu/Cy is currently being tested in a phase II study.

Adenovirus infection in paediatric allogeneic stem cell transplantation recipients is a major independent factor for significantly increasing the risk of treatment related mortality.

Adenovirus infection is a significant complication in paediatric AlloSCT recipients with a mortality rate for disseminated adenovirus that may exceed 80%. We sought to determine the incidence, risk factors, and associated outcomes of adenovirus infection in 123 consecutive paediatric AlloSCT recipients. Adenovirus was diagnosed by antigen detection or viral culture, and was defined by isolation of virus with presence of correlating clinical symptoms. The probability of developing adenovirus infection was 12.3% (CI(95) 6.0-18.6). There were no statistically significant differences in probability of adenovirus infection in univariate analysis of risk factors including donor source, use of ATG/Alemtuzumab, ≥ Grade II GVHD, among others (age, diagnosis, conditioning regimen). Probability of overall survival for patients that experienced adenovirus infection was 15.4% vs. 50% for those without adenovirus (P = 0.0286). In multivariate analysis, the most important risk factor for an increased risk of death was adenovirus infection [HR 3.15 (CI(95) 1.6-6.18) P = 0.0009]. In this series of paediatric AlloSCT recipients, the development of adenovirus infection was the leading multivariate predictor of treatment-related mortality. Enhanced surveillance with adenovirus PCR and identification of the risk factors associated with poor outcomes from adenovirus infection may identify patients that may benefit from pre-emptive therapeutic interventions including adenovirus-specific cellular immunotherapies.

T cell depletion utilizing CD34(+) stem cell selection and CD3(+) addback from unrelated adult donors in paediatric allogeneic stem cell transplantation recipients.

CD34-selected haploidentical and unrelated donor allogeneic stem cell transplantation (AlloSCT) in paediatric recipients is associated with sustained engraftment and low risk of acute graft-versus-host disease (aGVHD), but limited by delayed immune reconstitution and increased risk of viral and fungal infection. The optimal dose of donor T cells to prevent graft failure and minimize risk of early opportunistic infection and post-transplant lymphoproliferative disorder (PTLD), while avoiding severe aGVHD, remains unknown. We prospectively studied CD34-selected 8-10/10 human leucocyte antigen (HLA)-matched unrelated donor (MUD) peripheral blood stem cell transplantation (PBSCT) in a cohort of 19 paediatric AlloSCT recipients with malignant (n = 13) or non-malignant (n = 6) diseases. T cells were added back to achieve total dose 1·0-2·5 × 10(5)  CD3(+) /kg. GVHD pharmacoprophylaxis consisted only of tacrolimus. All patients engrafted neutrophils. Probabilities of grade II-IV aGVHD, limited chronic GVHD (cGVHD), and extensive cGVHD were 15·8%, 23·3%, and 0%, respectively. One patient developed PTLD. One-year infection-related mortality was 5·6%. T cell immune reconstitution was delayed. One-year overall survival was 82·3%. Five patients with malignant disease ultimately died from progressive disease. CD34-selected MUD PBSCT using a defined dose of T cell add-back resulted in high rates of engraftment and low risk of grade II-IV aGVHD, early transplantation-related mortality, and extensive cGVHD.

Risk-adapted chemoimmunotherapy using brentuximab vedotin and rituximab in children, adolescents, and young adults with newly diagnosed Hodgkin's lymphoma: a phase II, non-randomized controlled trial.

BACKGROUND: Cure rates for Hodgkin's lymphoma are excellent, but excess short-term and long-term morbidities from treatment remain a concern. Immunotherapy targeting both tumor antigens and the immunosuppressive tumor microenvironment in children, adolescents, and young adults with Hodgkin's lymphoma may improve early response rates and eliminate toxic chemotherapy and radiation, thus minimizing toxicity. We conducted a phase II study to evaluate the safety and overall response rate of brentuximab vedotin and rituximab in combination with risk-adapted chemotherapy in children, adolescents, and young adults with newly diagnosed classic Hodgkin's lymphoma (cHL). METHODS: This is a prospective, phase II, non-randomized, risk-assigned study. Patients were treated and evaluated between 2012 and 2020. Eligible patients were aged ≥1 and ≤30 years old with advanced stage, intermediate-risk, and high-risk newly diagnosed cHL. Patients received four or six cycles of brentuximab vedotin (1.2 mg/kg), doxorubicin (25 mg/m2), vinblastine (6 mg/m2), dacarbazine (375 mg/m2), and rituximab (375 mg/m2). Early response was evaluated following two cycles of therapy. Involved field radiotherapy (IFRT) was restricted to high-risk patients with both bulky disease and slow response or those not in complete response at the end of chemoimmunotherapy. RESULTS: Thirty patients were enrolled, with a median age of 15 years (4-23). There were 18 intermediate-risk and 12 high-risk patients. Toxicities included grade III mucositis (3%), infusion reaction (3%), and peripheral neuropathy (6%). There was a 100% complete response rate on completion of chemoimmunotherapy. Eighteen patients (60%) achieved a rapid early response. Four patients (13%) required IFRT. The 5-year event-free and overall survival rates were 100%, with a median follow-up of 62 months (18-105). CONCLUSIONS: Immunotherapy with brentuximab vedotin, rituximab, and risk-adapted chemotherapy is safe in children, adolescents, and young adults with newly diagnosed cHL. We have demonstrated 100% complete response and 100% event-free and overall survival rates at a median 5-year follow-up, with a significant reduction in use of more toxic chemotherapy and IFRT. A larger cohort is required to confirm these preliminary findings. TRIAL REGISTRATION NUMBER: NCT02398240.

Significant improvement of child physical and emotional functioning after familial haploidentical stem cell transplant.

Allogeneic stem cell transplantation (AlloSCT) represents the only curative therapy for sickle cell disease (SCD). However, limited availability of matched related donors and suboptimal outcomes following AlloSCT with unrelated donors has led to investigation of alternative donors. Among children with high-risk SCD, we evaluated health-related quality of life (HRQoL) impact in the two years following familial haploidentical SCT. HRQoL was collected from parent and child raters, using the Child Health Ratings Inventories Generic measure and haploidentical SCT-specific module. Repeated measures models were fit to assess HRQoL changes over time and by rater. Nineteen children (mean age 12.9 yrs [standard deviation, 5.3]; 63% male) and their parents were included. There were no differences in the 2-yr trajectories of child physical or emotional functioning (EF) by rater. Child physical functioning and EF scores were significantly lower at day +45 than baseline, but scores recovered by day +180. There was significant improvement in EF (p = 0.03) at 2 yrs vs baseline. A similar pattern of scores over time was seen for parent ratings of child's global HRQoL. Despite treatment intensity in the initial months following AlloSCT, patient scores recovered or exceeded baseline scores at two years. This trial is registered at clinicaltrials.gov (NCT01461837).

Donor chimerism and immune reconstitution following haploidentical transplantation in sickle cell disease.

Introduction: We previously reported the initial results of a phase II multicenter transplant trial using haploidentical parental donors for children and aolescents with high-risk sickle cell disease achieving excellent survival with exceptionally low rates of graft-versus-host disease and resolution of sickle cell disease symptoms. To investigate human leukocyte antigen (HLA) sensitization, graft characteristics, donor chimerism, and immune reconstitution in these recipients. Methods: CD34 cells were enriched using the CliniMACS® system with a target dose of 10 x 106 CD34+ cells/kg with a peripheral blood mononuclear cell (PBMNC) addback dose of 2x105 CD3/kg in the final product. Pre-transplant HLA antibodies were characterized. Donor chimerism was monitored 1-24 months post-transplant. Comprehensive assessment of immune reconstitution included lymphocyte subsets, plasma cytokines, complement levels, anti-viral T-cell responses, activation markers, and cytokine production. Infections were monitored. Results: HLA antibodies were detected in 7 of 11 (64%) evaluable patients but rarely were against donor antigens. Myeloid engraftment was rapid (100%) at a median of 9 days. At 30 days, donor chimerism was 93-99% and natural killer cell levels were restored. By 60 days, CD19 B cells were normal. CD8 and CD4 T-cells levels were normal by 279 and 365 days, respectively. Activated CD4 and CD8 T-cells were elevated at 100-365 days post-transplant while naïve cells remained below baseline. Tregs were elevated at 100-270 days post-transplant, returning to baseline levels at one year. At one year, C3 and C4 levels were above baseline and CH50 levels were near baseline. At one year, cytokine levels were not significantly different from baseline. Discussion: These results suggest that haploidentical transplantation with CD34-enriched cells and peripheral blood mononuclear cell addback results in rapid engraftment, sustained donor chimerism and broad-based immune reconstitution.

A comparison of immune reconstitution and graft-versus-host disease following myeloablative conditioning versus reduced toxicity conditioning and umbilical cord blood transplantation in paediatric recipients.

Immune reconstitution appears to be delayed following myeloablative conditioning (MAC) and umbilical cord blood transplantation (UCBT) in paediatric recipients. Although reduced toxicity conditioning (RTC) versus MAC prior to allogeneic stem cell transplantation is associated with decreased transplant-related mortality, the effects of RTC versus MAC prior to UCBT on immune reconstitution and risk of graft-versus-host disease (GVHD) are unknown. In 88 consecutive paediatric recipients of UCBT, we assessed immune cell recovery and immunoglobulin reconstitution at days +100, 180 and 365 and analysed risk factors associated with acute and chronic GVHD. Immune cell subset recovery, immunoglobulin reconstitution, and the incidence of opportunistic infections did not differ significantly between MAC versus RTC groups. In a Cox model, MAC versus RTC recipients had significantly higher risk of grade II-IV acute GVHD [Hazard Ratio (HR) 6·1, P = 0·002] as did recipients of 4/6 vs. 5-6/6 HLA-matched UCBT (HR 3·1, P = 0·03), who also had significantly increased risk of chronic GVHD (HR 18·5, P = 0·04). In multivariate analyses, MAC versus RTC was furthermore associated with significantly increased transplant-related (Odds Ratio 26·8, P = 0·008) and overall mortality (HR = 4·1, P = 0·0001). The use of adoptive cellular immunotherapy to accelerate immune reconstitution and prevent and treat opportunistic infections and malignant relapse following UCBT warrants further investigation.

Interleukin (IL)-15 in combination with IL-2, fms-like tyrosine kinase-3 ligand and anti-CD3 significantly enhances umbilical cord blood natural killer (NK) cell and NK-cell subset expansion and NK function.

BACKGROUND AIMS: Interleukin (IL)-15 and fms-like tyrosine kinase-3 (FLT-3) are crucial factors for the development of human and murine natural killer (NK) cells. Previously, we have demonstrated significant ex vivo expansion and activation of unrelated cord blood (UCB) NK cells with an antibody/cytokine cocktail consisting of anti-CD3 + IL-2 + IL-12 + IL-7 and anti-CD3 + IL-2 + IL-12 + IL-18. METHODS: In the current experiments, we investigated the effects of short-term culture with anti-CD3 + IL-2 + FLT-3 + IL-15 on cord blood (CB) NK cell and NK-cell subset expansion and function. CB mononuclear cells were cultured for 48 h in AIM-V media or AIM-V + IL-2 (5 ng/mL) + anti-CD3 (50 ng/mL) + FLT-3 (50 ng/mL) ± escalating doses of IL-15 (1, 10 or 100 ng/mL). Flow cytometric analysis was performed using various fluorescent-conjugated monoclonal antibodies. In vitro cytotoxicity was determined with a standard europium assay against K562 and Daudi cells. RESULTS: There was a 4.8-fold significant increase in NK-cell population (CD3(-)/16(+)/56(+); P < 0.03), 21-fold significant increase in CD3(-)/56(+)/158a(+) (KIR2DL1/S1; P < 0.002), 46-fold significant increase in CD3(-)/56(+)/158b(+) (KIR2DL1/S2; P < 0.002) and 11.5-fold significant increase in CD3(-)/56(+)/NKB1(+) (KIR3DL1; P < 0.01). We also noted a significant increase in both NK and lymphokine-activated killer (LAK) cytotoxicity with IL-2 + anti-CD3 + FLT-3 + IL-15 (100 ng/mL) compared with IL-2 + anti-CD3 + FLT-3 and media alone against K562 (P < 0.01) and Daudi (P < 0.001), respectively. CONCLUSIONS: We have demonstrated a significant increase in UCB NK cells and NK cells expressing a variety of killer immunoglobulin-like receptor (KIR) receptors after short-term culture with anti-CD3, IL-2, FLT-3 and IL-15. Furthermore, there was a significant increase in in vitro NK/LAK cell cytotoxicity.

Stable to improved cardiac and pulmonary function in children with high-risk sickle cell disease following haploidentical stem cell transplantation.

Children with sickle cell disease (SCD) are at high-risk of progressive, chronic pulmonary and cardiac dysfunction. In this prospective multicenter Phase II trial of myeloimmunoablative conditioning followed by haploidentical stem cell transplantation in children with high-risk SCD, 19 patients, 2.0-21.0 years of age, were enrolled with one or more of the following: history of (1) overt stroke; (2) silent stroke; (3) elevated transcranial Doppler velocity; (4) multiple vaso-occlusive crises; and/or (5) two or more acute chest syndromes and received haploidentical transplants from 18 parental donors. Cardiac and pulmonary centralized cores were established. Pulmonary function results were expressed as percent of the median of healthy reference cohorts, matched for age, sex, height and race. At 2 years, pulmonary functions including forced expiratory volume (FEV), FEV1/ forced vital capacity (FVC), total lung capacity (TLC), diffusing capacity of lung for carbon monoxide (DLCO) were stable to improved compared to baseline values. Importantly, specific airway conductance was significantly improved at 2 years (p < 0.004). Left ventricular systolic function (fractional shortening) and tricuspid regurgitant velocity were stable at 2 years. These results demonstrate that haploidentical stem cell transplantation can stabilize or improve cardiopulmonary function in patients with SCD.

Obinutuzumab (GA101) vs. rituximab significantly enhances cell death, antibody-dependent cytotoxicity and improves overall survival against CD20+ primary mediastinal B-cell lymphoma (PMBL) in a xenograft NOD-scid IL2Rgnull (NSG) mouse model: a potential targeted agent in the treatment of PMBL.

Primary mediastinal large B-cell lymphoma (PMBL), a distinct mature B-cell lymphoma, expresses CD20 and has recently been successfully treated with the combination of a type I anti-CD20 monoclonal antibody, rituximab, with multiple combination chemotherapy regimens. Obinutuzumab is a glycoengineered type II anti-CD20 monoclonal antibody (mAb), recognizing a unique CD20 extracellular membrane epitope with enhanced antibody dependent cellular cytotoxicity (ADCC) vs rituximab. We hypothesize that obinutuzumab vs rituximab will significantly enhance in-vitro and in-vivo cytotoxicity against PMBL. PMBL cells were treated with equal dose of obinutuzumab and rituximab for 24 hours (1-100 µg/ml). ADCC were performed with ex-vivo expanded natural killer cells at 10:1 E: T ratio. Mice were xenografted with intravenous injections of luciferase expressing Karpas1106P cells and treated every 7 days for 8 weeks. Tumor burden was monitored by IVIS spectrum system. Compared with rituximab, obinutuzumab significantly inhibited PMBL cell proliferation (p = 0.01), promoted apoptosis (p = 0.05) and enhanced ADCC (p = 0.0002) against PMBL. Similarly, in PMBL xenografted NOD scid gamma mice, obinutuzumab significantly enhanced survival than rituximab when treated with equal doses (p = 0.05). Taken together our results suggest that obinutuzumab significantly enhanced natural killer cytotoxicity, reduced PMBL proliferation and prolonged the overall survival in humanized PMBL xenografted NOD scid gamma mice.

Incidence of Viral and fungal infections following busulfan-based reduced-intensity versus myeloablative conditioning in pediatric allogeneic stem cell transplantation recipients.

Reductions in the duration and nadir of neutropenia have translated into a significant decrease in bacteremia in adult recipients of allogeneic stem cell transplantation (allo-SCT) with reduced-intensity conditioning (RIC) during the first 30 days after transplantation. It remains to be determined whether RIC allo-SCT also will result in a decrease in systemic viral infections (SVIs) and invasive fungal infections (IFIs), which are more dependent on alterations in cellular immunity. We compared the incidence of SVIs and IFIs in children receiving busulfan-based RIC allo-SCT and in children receiving myeloablative conditioning (MAC) allo-SCT for various malignant and nonmalignant diseases. Allo-SCT recipients at risk for cytomegalovirus (CMV) received ganciclovir/foscarnet, and most of the patients received antifungal prophylaxis with liposomal amphotericin B until day +100. Eighty-six patients (median age, 7.5 years; 70% with malignant disease, 30% with nonmalignant disease; 80% average risk, 20% poor risk) were evaluated. The probability of developing grade II-IV acute graft-versus-host disease (aGVHD) was 29.1% (95% confidence interval [CI]=16.7%-41.6%) in RIC allo-SCT versus 40.3% (95% CI=23.9%-56.6%) in MAC allo-SCT (P=.23), and that of chronic GVHD (cGVHD) was 28.9% (95% CI=14.7%-43.0%) in RIC allo-SCT versus 28.4% (95% CI=10.5%-46.3%) in MAC allo-SCT (P=.73). The overall probability of developing an SVI was 58%, and that of developing an IFI was 15%. These probabilities did not differ significantly by conditioning intensity. In a multivariate Cox regression model, the following were identified as independent risk factors for invasive fungal infection: older age (hazard ratio [HR]=1.3; 95% CI=1.1-1.6; P=< .01), poor risk status (HR=6.5; 95% CI =1.1-37.4; P=.03), and CMV-positive recipient (high vs low CMV risk group, HR=26.7; 95% CI=3.4-210.8; P=< .01). Overall infection-related mortality was only 1.1% (1/86) for SVIs and 2.3% (2/86) for IFIs. Our data indicate that RIC allo-SCT does not carry a lower risk of SVIs and IFIs than MAC allo-SCT in pediatric recipients.