Comparing between HLA-matched sibling donor allogenic HSCT and non-sibling matched related donor allogenic HSCT outcome in pediatric patients; single center retrospective study.

BACKGROUND: Extended family donor search other than siblings may yield an HLA matched donor in communities with high rate of consanguinity. The outcome of patients who are transplanted from non-sibling matched related donors (NS-MRD) including engraftment and graft versus host disease (GVHD) are scarce in comparison with matched sibling donor (MSD). METHODS: We retrospectively reviewed the outcome of all our pediatric hematopoietic stem cell transplantation (HSCT) patients who had non-sibling matched related donor and controlled them with matched sibling donor HSCT (based on age, indication of HSCT, conditioning regimen, GVHD prophylaxis, serotherapy, stem cell source and cytomegalovirus status). RESULTS: A total of 76 patients were reviewed during study period. Thirty patients (39.5%) in NS-MRD arm and 46 patients in MSD (60.5%) were identified after matching in age, disease, and conditioning regimens. All patients had similar approach including stem cell source and GVHD prophylaxis (CNI + 2nd agent). Out of the NS-MRD group, 18 patients (59%) had one of their parents as a donor and the rest as second degree relatives. Both groups were equally distributed and were homogeneous. Both groups had no statistically significant difference in outcome including engraftment, GVHD and Chimerism tests results. GVHD was seen in (13%) NS-MRD patients compared to (11%) in MSD patients. All patients remain alive with median follow up of 1249 days (431-3525). CONCLUSIONS: This study showed no significant difference in allogenic HSCT outcomes between matched sibling donors and non-sibling matched related donors and support using the same management approach in terms of conditioning therapy, GVHD prophylaxis, and serotherapy only if indicated.

Human leucocyte antigen-matched related haematopoietic stem cell transplantation using low-dose cyclophosphamide, fludarabine and thymoglobulin in children with severe aplastic anaemia.

When human leucocyte antigen-matched related donors are available, haematopoietic stem cell transplantation (HSCT) in children with severe aplastic anaemia (SAA) represents the standard of care. Cyclophosphamide (Cy) 200 mg/kg and anti-thymocyte globulin (ATG) are frequently administered, but to-date, no standard conditioning regimen exists. In this study, we investigated the efficacy of a unified HSCT conditioning protocol consisting of low-dose Cy 80 mg/kg, fludarabine and ATG. Data were reviewed from children aged ≤14 years with either acquired SAA or non-Fanconi anaemia inherited bone marrow failure syndrome (IBMFS) between 2011 and 2022 at various Saudi institutions. Graft-versus-host disease (GVHD) prophylaxis included mycophenolate mofetil and calcineurin inhibitors. HSCT was performed in 32 children (17 females and 15 males). Nine patients had deleterious mutations (two ERCC6L2, two ANKRD26, two TINF2, one LZTFL1, one RTEL1 and one DNAJC21). Four patients had short telomeres. All 32 patients engrafted successfully. At 3 years post-transplant, the event-free survival was 93% and overall survival was 95%. Two patients experienced secondary graft failure or myelodysplastic syndrome. A low probability of GVHD was observed (one acute GVHD II and one mild chronic GVHD). These data highlight how HSCT using low-dose Cy as part of a fludarabine-based regimen is safe and effective in SAA/non-Fanconi anaemia IBMFS.

Antimicrobial prophylaxis and the rate of blood stream infections and Clostridioides difficile in pediatric stem cell transplantation: A single-center retrospective study.

BACKGROUND: The use of prophylactic antibiotics in the pre-engraftment period to minimize the risk of bacteremia is debatable given concerns of Clostridioides difficile (C. diff), antibiotics resistance, and disruption of gut microbiota. METHODS: We retrospectively reviewed the rate and characteristics of bacteremia and C. diff infections within the first 100 days post-HSCT in all pediatric patients who received routine antibacterial prophylaxis during HSCT from 2015 to 2018. C. diff infection was defined by the presence of three or more unformed stools in 24 h and positive stool test for C. diff or its toxins. RESULTS: One hundred and thirty-five (100 allogeneic and 35 autologous) transplants in 123 patients were eligible for analysis. Median age at transplant was 7.1 (range 0.2-13.7), 67 (55%) were women, and diagnosis was malignant condition in 68 patients. Median time to neutrophil engraftment was 18 days (13-23). Cefepime or piperacillin-tazobactam prophylaxis was used in 105 (78%) and 28 (21%) of patients, respectively. Only five (3%) patients had bacteremia during the pre-engraftment period, and 13 (11%) patients developed bacteremia postengraftment. Septic shock was present in only one patient pre-engraftment and was due to gram-negative bacteria. All patients who developed bacteremia received MAC. Thirteen patients (10%) of patients fulfilled C. diff infection definition. There was no mortality related to bacterial infections among our patients. CONCLUSIONS: The use of antibiotic prophylaxis was associated with low rate of bacteremia in the pre-engraftment period and a 10% risk of C. diff infections. More studies are needed to better evaluate the efficacy of antibiotic prophylaxis in HSCT patients.

Outcomes of blinatumomab based therapy in children with relapsed, persistent, or refractory acute lymphoblastic leukemia: a multicenter study focusing on predictors of response and post-treatment immunoglobulin production.

The management of Refractory/Relapsed B-cell Acute Lymphoblastic Leukemia (R/R ALL) remains challenging. Incorporating blinatumomab in R/R ALL treatment has shown encouraging results. We describe the outcome and predictors of response in children receiving blinatumomab as a bridge to definitive therapy. Immunoglobulin (Ig) G and viral serology before and after therapy were evaluated. Thirty-three patients that failed standard first-line treatments due to relapsed ALL (n = 22), persistent minimal residual disease (MRD) (n = 8), or refractory disease (n = 3) received blinatumomab. Grade 2 toxicity occurred in 27.2% of patients. MRD remission (<0.01%) was achieved in 72.7% of patients. Pre-blinatumomab absolute lymphocyte count (ALC) and MRD/ALC ratio significantly associated with MRD-response. Patients with t(1;19) translocation had lower response rate, compared to all other cytogenetic categories (p = 0.013). One-year event-free survival (EFS) and overall survival (OS) were 69.2% and 79.7%, respectively. Analysis of OS and EFS showed pre-blinatumomab MRD level, ALC, MRD/ALC ratio, t(1;19), and post-blinatumomab MRD remission associated with survival. Following blinatumomab, 83% (15/18) of tested patients had low IgG levels. IgG seronegative status was observed in 83% (12/15) for varicella zoster, 35% (6/17) for herpes zoster, 18% (3/17) for cytomegalovirus, and 26% (5/17) for Epstein Barr virus. Blinatumomab produced encouraging results in children with R/R ALL and low disease burden bridging to definitive therapy. Incorporating baseline genetics and biomarkers may help identify subgroups likely to be responsive/resistant to therapy. Viral serological testing pre- and post-blinatumomab is recommended to optimize supportive and preemptive therapy.Supplemental data for this article is available online at https://doi.org/10.1080/08880018.2022.2049936 .

The effect of intensity of conditioning regimen on the outcome of HSCT in children with sickle cell disease.

BACKGROUND: Allogeneic hematopoietic stem cell transplantation (HSCT) provides a cure for patients with sickle cell disease (SCD). This study describes the effect of conditioning regimen intensity on HSCT outcomes among children younger than 14 years with SCD. METHODS: Transplants from HLA-matched related donors (MRD) and unrelated donors (MUD) using either myeloablative conditioning (MAC) regimens or reduced intensity conditioning (RIC) regimens were considered. Event-free survival (EFS) was the primary endpoint. Secondary endpoints included overall survival (OS) and occurrence of GVHD. RESULTS: 48 SCD patients underwent HSCT, 45 (93.8%) patients had MRD, 1 (2.1%) had 9/10 related donor, and 2 (4.1%) had MUD. The median age at transplant was 8.6 years (range, 3.1-13.8). Conditioning regimens were myeloablative (MAC) in 41 (85.4%) patients and of reduced intensity in 7 (14.6%) patients. EFS at 2 years was 100% among MAC group compared to 29% in the RIC group (p < .001). The median follow-up was 43.4 months (range 26.8-134). All events in the RIC group were secondary graft failure. However, OS was 100% in both groups at 2 years. Acute GVHD II-IV was diagnosed in 2 (4.1%) patients. Chronic GVHD occurred in 2 (4.1%) patients. GVHD did not occur in patients who underwent MUD HSCT. CONCLUSIONS: MAC in children with SCD is well tolerated and associated with an excellent outcome for HLA-matched HSCT in SCD. There was a high rate of secondary graft failure with the use of RIC. Future studies are needed to optimize RIC regimens in HSCT of children with SCD.

The outcome and complications of total parenteral nutrition in pediatric hematopoietic stem cell transplantation.

BACKGROUND: Nutritional support posthematopoietic stem cell transplantation (HSCT) with total parenteral nutrition (TPN) or nasogastric tube feeding (NGT) in pediatric patients is associated with benefits and risks. METHODS: We retrospectively reviewed the indication of TPN use in our pediatric HSCT patients and its impact on survival and possible related complications. RESULTS: A total of 228 HSCTs were performed during the study period. TPN was used in 144 patients (63.2%) for a median of 14 days, while 8.8% had NGT feeding and 28% were able to tolerate oral feeding. Severe mucositis was seen in 104 TPN patients (72.2%) in comparison with 22 patients (26.2%) who were on Enteral Nutrition (EN) (p = <.001). Sinusoidal obstruction syndrome (SOS) was seen in 19 (13.2%) patients who had TPN compared to none in the patients who received EN (p = .001). The majority of patients who had SOS received myeloablative conditioning (MAC) therapy for hemoglobinopathy. Acute graft-versus-host disease (aGVHD) was seen in 24.8% of TPN patients and 9.1% of non-TPN patients (p = .01). However, there were no statistically significant differences in chronic GVHD, bacteremia, and patients' survival between both groups. CONCLUSIONS: TPN is commonly used after pediatric HSCT in cases of severe mucositis. NGT feeding was found to be the least used nutritional support method. SOS and aGVHD were associated more frequently in TPN patients compared to EN patients. This suggests the possible disadvantages of TPN and importance of SOS preventative measures in high-risk patients.

Clinical course and outcomes of COVID-19 in hematopoietic cell transplant patients, a regional report from the Middle East.

The coronavirus disease-2019 (COVID-19) caused by SARS Coronavirus 2 (SARS-CoV-2) is a potentially lethal infection. Cancer patients, and specifically hematopoietic cell transplant (HCT) recipients are severely immunocompromised and may be at a higher risk of a complicated course with this infection. We aimed to study the COVID-19 outcomes and severity in post HCT patients. We retrospectively reviewed post-HCT patients diagnosed with COVID-19 between March 15, 2020, and December 1, 2020 at 10 transplant centers across the Middle East. We identified 91 patients with confirmed SARS-CoV-2 infection across 10 transplant centers. The median age upon presentation with COVID-19 was 35. Fifty two patients were post allo-HCT while the remaining 39 patients were post auto-HCT. The median time from transplant was 14.9 months. Mortality rate was 4.4%. Hospital admission rate was 53%. ICU admission rate was 14%. Mechanical ventilation rate was 10%. Oxygen supplementation rate was 18%. Time from HCT to COVID-19 >6 months was associated with lower admission rates and lower rates of the "severity" composite endpoint. Antibody responses was seen 67% of evaluable patients. In this series of HCT recipients, we report overall favorable clinical outcomes for patients with COVID-19 and provide preliminary insights into the clinical course of this disease in this specific population.

Orbital extramedullary leukemia relapse in a pediatric patient post-CART cell therapy-Case report.

CART therapy is an approved therapy in advanced ALL. The mechanism of relapse post-CART therapy is under vigorous research. We report a 9-year-old boy who received CD19-CART therapy after BM ALL relapse post-HSCT. He presented with unilateral eye swelling which was initially managed as orbital cellulitis. Later on, it was proven to be an isolated ALL orbital relapse without peripheral blood B-cell detection or BM involvement. Despite radiotherapy, he subsequently developed refractory CD19 positive ALL BM relapse. This case highlights the possibility of unusual relapse sites after CART-therapy and that regular peripheral B-cell monitoring is not enough to assure remission status. Better monitoring tools are needed to detect early disease relapse. Further understanding of the pathophysiology of isolated extramedullary relapse post-CART therapy is warranted to improve the management of such challenging presentations.

Spectrum of medulloblastoma subtypes and frequency of MYC amplification; Experience from a tertiary care center in Saudi Arabia.

OBJECTIVE: To clarify the spectrum of morphological and molecular subtypes of medulloblastoma (MBL), in addition to MYC and MYCN amplification statuses in a cohort of Saudi patients. The latter was correlated with patient outcome. METHODS: We conducted a retrospective cohort study of 57 patients with MBL, diagnosed at the central laboratory of King Abdulaziz Medical City in Riyadh, Saudi Arabia, between 2006 and 2019. Molecular analysis for MYC and MYCN amplification was performed for the 19 most recently diagnosed patients. RESULTS: Classic MBL was the most prevalent histologic subtype and MBL with extensive nodularity was the rarest. The non-WNT/non-SHH molecular subgroup was the most common while the WNT-activated was the least common. Among 19 patients analyzed, MYC and MYCN amplifications were discovered in 2 (10.5%) and 1 (5.3%) cases, respectively, using interphase fluorescence in-situ hybridization. The 2 MYC amplified cases belonged to the large cell/anaplastic subtype and had the worst outcomes. CONCLUSION: The MYC amplification corresponded with poor prognosis, the large cell/anaplastic variant of MBL, and the non-WNT/non-SHH molecular subtype.

Incidence trends of childhood acute lymphoblastic leukemia in Saudi Arabia: Increasing incidence or competing risks?

INTRODUCTION: The incidence of childhood acute lymphoblastic leukemia (cALL) varies between countries likely as a result of competing risks including infections, access-to-care, socioeconomic influences, and/or ethnicity. However, little is known about disease burden in high-income Arab countries offering free-of-charge healthcare. The hypothesis was that, due to population characteristics (young age, high fertility and parental consanguinity rate), the incidence of cALL in Saudi Arabia is equal or higher than that observed in high-income Western countries. METHODS: Saudi databases were used to calculate the incidence of cALL from 2001 to 2014. Incidence trends over time of children with ALL, 14-years of age or younger, were analyzed and compared with those reported in USA. RESULTS: The age-adjusted incidence over the years was lower in Saudi Arabia compared to USA. However, the incidence trend of cALL in Saudi Arabia was increasing at a rate higher than that observed in USA (p < 0.001). The overall incidence of cALL in Saudi Arabia increased from 1.58/100,000 in 2001 to 2.35/100,000 population in 2014. The median annual increase was 4.58 %. The incidence in males increased from 1.88 to 2.71/100,000, and from 1.21 to 1.86/100,000 population in females. CONCLUSIONS: The reported incidence of cALL in Saudi Arabia is rapidly increasing. The increasing trend may reflect evolving socioeconomic structure, improved access-to-cancer care, and improved diagnosis/ reporting capacity. This highlights the need for better understanding of cALL causes and the need for the formation of separate national pediatric cancer registries in different countries to monitor childhood cancer incidence trends.

Successful hematopoietic stem cell transplant in leukocyte adhesion deficiency type III presenting primarily as malignant infantile osteopetrosis.

Leukocyte adhesion deficiency type III (LAD-III) is caused by mutations in FERMT3 that encodes Kindlin-3 which regulates integrins activation. LAD-III predisposes to infections and bleeding. Osteopetrosis was reported in some cases. We report three patients who presented as malignant infantile osteopetrosis. One had recurrent infections and none had bleeding. Exome sequencing revealed a novel homozygous mutation in FERMT3 c.1555C > T (p.Gln519Ter). Two patients underwent successful hematopoietic stem cell transplant (HSCT) from matched siblings with resolution of osteopetrosis. The third patient died secondary to sepsis prior to HSCT. Our results support early HSCT in LAD-III prior to the occurrence of life-threatening complications.

Management of Adolescent Low-Risk Classical Hodgkin Lymphoma: Which Chemotherapy Backbone Gives the Best Chance of Omitting Radiotherapy Safely.

Even though more than 90% of adolescents with low-risk classical Hodgkin lymphoma (LRcHL) will be cured with first-line therapy, many will suffer serious late toxic effects from radiotherapy (RT). The goals for care have shifted toward minimizing late toxic effects without compromising the outstanding cure rates by adapting a risk and response-based therapy. Recent published and ongoing randomized clinical trials, using functional imaging, may allow for better identification of those patients for whom RT may be safely omitted while maintaining excellent cure rates. To evaluate the best chemotherapy regimens with a reasonable toxicity profile and that are expected to have a high chance of omitting RT based on a response-directed therapy while maintaining high cure rates, a mini review was conducted of the recent clinical trials in pediatric and adult LRcHL. The UK RAPID trial chemotherapy backbone (3 × ABVD) followed by a response-based positron emission tomography scan offers up to a 75% chance of safely omitting RT without compromising the cure rate, which remained well above 90%.