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Stem cell transplantation (HCT) restores normal hematopoiesis in Fanconi anemia patients but survivors remain prone to long-term complications. This study was conducted to review the late effects and psychosocial adjustment in life for long term survivors of FA patients. Medical records of 149 patients with FA who underwent allogeneic HCT were reviewed. Cumulative probabilities of OS at 10- and 15 years were 76.6%±3.6% and 69.8%±4.4% respectively. Median OS time was 22.8 years. Eighty-seven patients were successfully contacted for follow up. Late-effects were reported by 47. The most commonly reported late-effects were hypothyroidism, amenorrhea and ocular problems. About two-third of our alive patients (n = 58, 66.7%) had achieved a minimum of high school education; only three (3.4%) got married. None had children. Of those 45 patients who were above 20 years of age at last contact, 42 (93.3%) were still living with their parents, two (5.0%) had rental accommodation and one female was living independently. Only nine (20%) of recipients who were above 20 years of age were able to secure an employment, two of whom were self-employed. Long term close follow-up is crucial to detect such complications. Psychological and social counseling should be an integral part of their follow up.

Background and Objective Neuroblastoma is the most common extracranial solid tumor found in pediatric patients. High-risk neuroblastoma (HR-NBL) can be characterized by metastasis, age, and other tumor characteristics that result in an adverse outlook for this patient cohort. The standard of care includes induction chemotherapy, surgery, followed by stem cell autologous transplant (ASCT), and later, antidisialoganglioside (anti-GD2) antibodies. In this study, we provide the survival and toxicity data of our HR-NBL patients treated with a single ASCT. Methods We retrospectively analyzed pediatric HR-NBL patients treated with single ASCT after a carboplatin, etoposide, and melphalan (CEM) regimen in our institution between January 1993 and December 2014. Results There were 99 evaluable patients with male predominance. The median age at diagnosis was 3 years. Most of our HR-NBL patients were stage 4 (88%). All patients received ASCT. Peripheral blood was the graft source in 58% of the patients. Time for hematological count recovery with bone marrow as a graft source was prolonged but not statistically significant when compared with PBSCs. Of all the patients, 58% received radiation therapy to residual disease. Overt secondary leukemia was not seen in any of these patients. Three-year overall survival (OS) was 68.5% ± 5.2% and the 3-year event-free survival (EFS) was (48.3% ± 5.2%). Conclusion Our HR-NBL patients tolerated high-dose chemotherapy well followed by single autologous stem cell transplant. Tandem transplant is a feasible option in our patient cohort. Apart from secondary solid tumors, there were no long-term complications seen.

In 2010, we reported the outcome of hematopoietic stem cell transplantation (HSCT) in 11 children with Griscelli syndrome type 2 (GS2). We report here the update on this cohort to include 35 patients. Twenty-seven (77%) patients received conditioning regimen including busulfan, cyclophosphamide with etoposide. Eight (23%) were given busulfan, fludarabine. Thiotepa was added to busulfan and fludarabine regimen in two patients; one received haploidentical marrow and one unrelated cord blood. Posttransplant clinical events included veno-occlusive disease (n = 7), acute (n = 8), or chronic (n = 1) graft-versus-host disease II–IV. With a mortality rate of 37.1% (n = 13) and a median follow-up of 87.7 months of the survivors, 5-year cumulative probability of overall survival (OS) for our cohort of patients was 62.7% (±8.2%). Cumulative probability of 5-year OS was significantly better in those who did not have hemophagocytic lymphohistiocytosis (HLH) prior to HSCT (100% vs. 53.3 ± 9.5%, P value: 0.042). Of the 16 patients with neurologic involvement before HSCT, 8 survived and 3 presented sequelae. OS at 5-year was 50 ± 12.5% and 73.3 ± 10.2% (P value: 0.320) in patients with and without CNS involvement, respectively. In conclusion, HSCT in patients with GS2 is potentially curative with long-term disease-free survival. Early HSCT before the development of the accelerated phase is associated with a better outcome.

Allogeneic hematopoietic cell transplantation (HCT) has been shown to restore normal hematopoiesis in patients with Fanconi anemia (FA), with excellent results in matched related donor HCT. Outcomes of alternative donor HCT are less favorable, however. In patients without FA, several reports have documented stable engraftment and/or a low risk of graft-versus-host disease (GVHD) using unmanipulated HLA-mismatched related donors and post-HCT cyclophosphamide (PT-CY) for GVHD prophylaxis. Data on the use of this approach in patients with FA are scarce, and thus we launched a study of HLA-mismatched related donor HCT in these patient. Here we report our findings in 19 patients. The conditioning was fludarabine 30 mg/m2/day for 5 days, antithymocyte globulin 5 mg/kg/day for 4 days, and total body irradiation (total dose, 200 cGy). GVHD prophylaxis was cyclosporine and mycophenolate and reduced doses of PT-CY, 25 mg/kg, on days +3 and +5. All patients exhibited absolute neutrophil count recovery. Grade III-IV acute GVHD occurred in 3 patients, and chronic GVHD occurred in 1 patient. At a mean follow-up of 38.3 ± 5.8 months, the 5-year probability of overall survival for our patients was 89.2% ± 7.2%. The regimen was well tolerated; hemorrhagic cystitis occurred in 7 patients, and severe mucositis occurred in 5 patients. There were 2 deaths; the primary cause of death was severe GVHD in 1 patient and leukemia recurrence in the other. We conclude that in patients with FA lacking a matched related donor, the use of mismatched related HCT with low-dose PT-CY is a viable option; it is well tolerated, with a high rate of engraftment and an acceptable incidence of GVHD.

Despite the high incidence of Down syndrome (DS) in Arab countires, the incidence and outcomes of myeloid leukemia of DS (ML-DS) have not been studied. We evaluated 206 pediatric acute myeloid leukemia (AML) patients diagnosed between 2005 and 2012 and identified 31 (15%) ML-DS. The incidence of ML-DS was 48 per 100,000 compared to 0.6 per 100,000 for AML in non-DS children. Thus, patients with DS had 80-fold increased risk of ML-DS compared to AML in non-DS children. The median age at diagnosis was 1.8 years, male/female ratio was 1.2, majority (84%) of patients had FAB-M7 subtype, and the cytogenetic abnormalities were normal karyotype (constitutional trisomy 21) in 48%, additional trisomy in 23%, and other aberrations in 29%. Complete remission, cumulative incidences of relapse (CIR), toxic-death, and 5-year event-free survival (EFS) rates were 96.8%, 19.4%, 13.1%, and 67.7±8.4%; respectively. In the present study, multivariate analysis revealed favorable outcome (5-year EFS 86.7±8.8%) for patients with normal karyotype. The incidence and clinical characteristics of ML-DS in Saudi patients were comparable to other reports. However, there is a need to optimize risk stratification and treatment intensity to reduce CIR and toxic death rates to further improve outcomes of patients with ML-DS.

Introduction Hematopoietic Stem Cell Transplantation (HSCT) recipients are at an increased risk of infections including but not limited to Hospital-acquired infections (HAIs), extrinsic factors such as health-care workers and visitors plays a vital role in minimizing HAIs. Pediatric Stem Cell Transplant Program at King Faisal Specialist Hospital & Research Centre, Riyadh is the national referral center for malignant and non-malignant cases indicative of a transplant, an average of 140 transplants performed per year Method Stringent compliance to institutional visiting hour's policy and hand-hygiene campaign in pediatric post-HSCT inpatient unit was reinforced in early 2017; a pre -/post intervention HAI rate is being reported as data analyzed retrospectively Results A total of 269 transplants performed on 260 recipients during 2015 to 2016 (pre-intervention), while 279 transplants on 262 recipients during 2017 to 2018 (post-intervention), a 33% decrease in HAI episodes (57 vs. 38) was observed with a decrease in HAI rate of 2.5% (4% vs. 6.5%); while the incidence density of HAI post-intervention was 2.69 per 1,000 patient-days, which reduced by 36% (4.2 per 1,000 patient-days). An increase in Average Length of Stay by 19% (19.15 days vs. 16.14 days) in relation to 4% increase in transplant episodes was observed; a decrease in long- stay (>60 days) patients by 2%, while the Bed Turnover rate improved by 4%. A major drop in Drug-resistant bacteremia, 60% (4 vs. 10) followed by C.difficile infection, 50% (16 vs 32 infections) observed, HAI-related mortality was not observed pre-/post intervention Conclusion Visits from family and friends eases some of the isolation experienced, in our experience strict adherence to policies coordinated by health-care professionals with cooperation from families help keep balance between the emotional well-being of the patient and risk associated with such visits. Further, analysis of HAIs during neutropenic vs. non-neutropenic stage of the patient, in addition to transplant-related outcomes is warranted.

Fanconi anemia (FA) cells are characterized by genomic instability, which places FA patients at risk for malignancies such as leukemia and oropharyngeal/urogenital cancers. The risk of development of leukemia is theoretically eliminated after hematopoietic cell transplantation (HCT). Mixed chimerism (MC) in FA patients might have a unique implication because the persistent existence of FA cells might give rise to a malignant clone. We have studied a large population of FA patients who underwent allogeneic HCT at our institution and report here the outcome according to chimerism status. Patients with FA who had evidence of progressive bone marrow failure and were blood products–transfusion dependent (packed red blood cells, platelets, or both) were included in the study. Those who had myelodysplasia (MDS) or an abnormal clone or evidence of leukemia were excluded. All but 3 patients had normal renal and cardiac function at the time of transplantation. In total, 160 patients with FA underwent allogeneic HCT at our center from January 1995 to December 2017; mean age at HCT was 8.4. Chimerism data at last follow-up visit were available on 97 patients who are the subjects of this analysis (no day +100 chimerism data on one of them). On day +100, 46 patients (47.9%) had full chimerism (FC) and 50 (52.1%) had MC, whereas at last follow-up 50 (51.5%) exhibited FC and the remaining 47 (48.5%) had MC. Cumulative incidence of all grades acute graft-versus-host disease (GVHD) was 13.4% and that of grade III to IV GVHD was 4.1%. Chronic GVHD was seen in eight (8.0%) patients. Incidence of severe acute GVHD (grade ≥ III) and that of chronic GVHD were not significantly associated with FC or MC measured at day +100 (P values = .347 and .254, respectively), nor at the last follow-up. Graft failure occurred in 2 patients; both from the MC at day +100 group. No graft failures occurred in the FC at day +100 group (P value = 1.00). At a median follow-up of 83.8 months (95% confidence interval, 51.0-116.6; range, 19.3-181.1 months) the cumulative probability of overall survival (OS) at 5 years was 95.7% ± 2.1%. Mean follow-up time in our cohort was 90.7 months. Five-year overall survival was not significantly associated with FC or MC evaluated at day +100 (95.7% ± 3.0% versus 95.6% ± 3.1%, P value = .908) nor at the last follow-up (96.0% ± 2.8% versus 95.4% ± 3.2%, P value=.925). No patient in either group developed MDS/leukemia during the follow-up period. We conclude that mixed chimerism in patients with FA appears to have no adverse effect on outcome in our follow-up period. A longer follow-up period is needed, however, to confirm the validity of this statement.

Introduction Hematopoietic Stem Cell Transplantation (HCT) is considered the curative treatment for patients with Primary Immune Deficiencies (PIDs). Finding a full matched Human leukocyte donor remains an obstacle for performing the bone marrow transplant in a timely fashion. Haplo-identical HCT is an alternative treatment option for patients, who do not have access to full-matched donor. We are reporting preliminary data on our experience of HCT in PID patients using haplo-identical donor with post-transplant Cyclophosphamide. Methods Eleven transplant naive PID patients were infused from June 2017 to August 2018 using a haplo-identical HLA donor at our institution. Eight (72.7%) of the recipients were male. Median age at infusion was 0.9 years (Min: 5.5 months Max: 2.3 years). Primary indications for transplantation included Severe Combined Immune Deficiency (SCID) in seven (63.6%), Omenn Syndrome in two (18.2%), and Chediak-Higashi syndrome and Combined Immunedeficiency in one (9.1%) each. All received GVHD prophylaxis comprising of Cyclophosphamide, Mycophenolate mofetil (MMF), and Cyclosporine regimen. Conditioning regimen was BU/FLU/Thiotepa (±ATG) in six (54.5%) recipients followed by BU/FLU/ATG in four (36.4%). Source of stem cells was bone marrow in ten patients (90.9%) while for the remaining one child PBSC was utilized. Results Eight patients (72.7%) had ANC engraftment with a median time to ANC recovery 15.5 days (Minimum: 13, maximum: 22) whereas, seven (63.6%) of our patients achieved platelets recovery (Median: 33 days, minimum: 16, maximum: 150). In terms of chimeric studies, all but one patient, engrafted at Day +100. Cumulative incidence of aGVHD was 27.3% (n=3); no chronic GVHD was recorded. At a median follow-up of 18.8 months (95% CI: 14.6-23.1), cumulative probability of overall survival at one year from infusion, for our patients is 72.7% (±13.4%). Hemorrhagic cystitis was seen in only one (9.1%) patient while two (18.2%) experienced mucositis (Grade1 or 2). Three (27.3%) contracted CMV infection and were successfully treated.At one-year follow-up lymphoid chimerism remains >95% donor type and CD3:1717 mm3 and CD19 521 mm3 Conclusion Preliminary outcome data on our small cohort of immunodeficiency patients who underwent HCT using Haplo-identical donor with Post-Cy is quite encouraging with durable and stable donor chimerism and CD3 and CD19 engraftment.

Background The outcome of childhood acute myeloid leukemia (AML) in first relapse (rAML) remains poor. Reported overall survival (OS) rates vary between high-income developed countries and those with fewer resources. The OS of rAML in high-income developing countries (HIDCs) has not been reported. Patients and Materials A multicenter study was performed in an HIDC. The outcome of patients with relapsed non-M3/non-Down syndrome AML was evaluated. Three-year OS was computed using the Kaplan-Meier method, and predictors of OS were analyzed using a Cox proportional hazards model. Results A total of 88 patients with non-M3/non-Down syndrome AML diagnosed between January 2005 and December 2012 with a first relapse were identified. Their 3-year OS was 22.6% ± 5.4%. Patients with inv(16) and t(8;21) had an OS of 75.0% ± 21.7% and 36.0% ± 16.1%, respectively. Worse outcomes were associated with “other intermediate” and 11q23 rearrangement AML (OS of 9.4% ± 8.7% and 10.7% ± 9.6%, respectively). Patients experiencing time to relapse (TTR) less than 1 year had shorter OS than those with a longer TTR (14.6% ± 5.4% vs. 41.1% ± 11.5%; P = .006). The outcome of patients after stem cell transplantation (SCT) in second complete remission (CR2) was superior compared with no SCT (50.9% ± 11.2% vs. 7.7% ± 4.6%; P = .001). TTR, risk group, CR2, and SCT in CR2 were the most significant predictors for survival. Conclusions rAML remains a clinical challenge. Genetic variability in outcomes was observed. A majority of patients with inv(16) were successfully salvaged post-relapse, whereas patients with 11q23 rearrangement had a poor prognosis. Only one-third of those with t(8;21) rAML survived. Better access to SCT in HIDCs is needed.

Background Hematopoietic cell transplantation (HCT) is a standard therapeutic modality for many hematological malignant and nonmalignant disorders. Advances in supportive care after HCT have led to improvement in survival. Secondary malignant neoplasm (SMN) is a devastating late effect after HCT that is associated with significant morbidity and high mortality. Methods Records of 1910 pediatric patients (pts) ≤14 years of age who underwent HCT at our center between 1995-2015 were reviewed to study the incidence of SMN after HCT in our population and potential risk factors. Factors studied were age at HCT, gender, indication of HCT, number and type of transplant, stem cells source, GVHD prophylaxis regimen, use of radiation-based conditioning regimens. Results A total of 2034 HCT were performed on 1910 pts; 1789 (93.7%) had 1 transplant, and 121(6.3%) ≥2 transplants; 25 pts (1.3%) developed SMN. Fifteen had solid tumors (Group A), 6 had leukemia or lymphoma (Group B) and 4 had post-transplant lymphoproliferative disorder (PTLD; Group C). Median time to development of SMN from first HCT was 100.8 months (range, 3.7-244.8). Approximately three quarters of pts who developed SMN were transplanted for non-malignant disorders (18 of 25, 72%), and amongst non-malignant disorders, bone marrow failure syndromes pts had the highest incidence (10 of 18, 55.6%, P-value 0.008). Twelve pts (48%) who developed SMN received radiation-based conditioning regimen (p-value 0.001). The 10-year probability of overall survival (OS) at 10-years for those who developed SMN was not significantly different than OS in those who did not (0.748±0.089 vs. 0.664±0.011, p-value: 0.154). Among those who developed SMN, 10-year OS was better in Group A compared to Group B and Group C (0.929±0.069, 0.625±0.213 and 0.250±217 respectively; p-value: 0.015). Conclusion SMN developed in 1.3% of our pts post HCT; use of radiation in the conditioning regimen appears to be a significant risk factor.`

Background Phenotypic overlap among the inherited bone marrow failure syndromes (IBMFSs) frequently limits the ability to establish a diagnosis based solely on clinical features. >70 IBMFS genes have been identified, which often renders genetic testing prolonged and costly. Since correct diagnosis, treatment and cancer surveillance often depend on identifying the mutated gene, strategies that enable timely genotyping are essential. Methods To overcome these challenges, we developed a next-generation sequencing assay to analyse a panel of 72 known IBMFS genes. Cases fulfilling the clinical diagnostic criteria of an IBMFS but without identified causal genotypes were included. Results The assay was validated by detecting 52 variants previously found by Sanger sequencing. A total of 158 patients with unknown mutations were studied. Of 75 patients with known IBMFS categories (eg, Fanconi anaemia), 59% had causal mutations. Among 83 patients with unclassified IBMFSs, we found causal mutations and established the diagnosis in 18% of the patients. The assay detected mutant genes that had not previously been reported to be associated with the patient phenotypes. In other cases, the assay led to amendments of diagnoses. In 20% of genotype cases, the results indicated a cancer surveillance programme. Conclusions The novel assay is efficient, accurate and has a major impact on patient care.

BACKGROUND Acute promyelocytic leukemia (APL) is a rare form of acute myelogenous leukemia (AML). Survival rates exceed 80% in developed countries. Successful treatments rely on all-trans retinoic acid with anthracycline-based chemotherapy. Availability of modern care and public knowledge play important roles in pediatric APL survival. METHOD A cytogenetic diagnosis of APL was confirmed in 30 (14.5%) out of 207 children consecutively diagnosed with de novo AML between January 2005 and December 2012 at nine cancer care centers in Saudi Arabia. Patients were treated based on the standard protocol used by the center following the PETHEMA or the C9710 treatment protocols. We modeled 5-year overall survival (OS), event-free survival (EFS) and cumulative incidence of relapse (CIR) vs. treatment and potential covariates of age at diagnosis, involvement of central nervous system (CNS), and white blood cell (WBC) levels. RESULTS The median age was 10.4 years with a male:female ratio of 1.9. WBC was 10 × 109/l or greater in 57% and CNS involvement was confirmed in 13%. OS, EFS, and CIR were 74 ± 12%, 55 ± 19%, and, 36 ± 17% respectively. No significant difference was found by treatment protocol. WBC levels were significantly prognostic for all negative events, but treatment with C9710 significantly ameliorated negative WBC effects. Overall outcomes were comparable to those reported in developed countries. CONCLUSIONS Access to modern care is likely to be a critical factor in successful and comparable outcomes of childhood APL across the globe. In the present study, utilizing a cytarabine-containing protocol improved outcome of high-risk pediatric patients with APL.

Diamond-Blackfan anemia (DBA) features hypoplastic anemia and congenital malformations, largely caused by mutations in various ribosomal proteins. The aim of this study was to characterize the spectrum of genetic lesions causing DBA and identify genotypes that correlate with phenotypes of clinical significance. Seventy-four patients with DBA from across Canada were included. Nucleotide-level mutations or large deletions were identified in 10 ribosomal genes in 45 cases. The RPS19 mutation group was associated with higher requirement for chronic treatment for anemia than other DBA groups. Patients with RPS19 mutations, however, were more likely to maintain long-term corticosteroid response without requirement for further chronic transfusions. Conversely, patients with RPL11 mutations were less likely to need chronic treatment. Birth defects, including cardiac, skeletal, hand, cleft lip or palate and genitourinary malformations, also varied among the various genetic groups. Patients with RPS19 mutations had the fewest number of defects, while patients with RPL5 had the greatest number of birth defects. This is the first study to show differences between DBA genetic groups with regards to treatment. Previously unreported differences in the rate and types of birth defects were also identified. These data allow better patient counseling, a more personalized monitoring plan, and may also suggest differential functions of DBA genes on ribosome and extra-ribosomal functions.

INTRODUCTION: Allogeneic hematopoietic stem cell transplantation (HSCT) is the only treatment modality offering cure or long-term survival for many hematologic malignancies, and non-malignant diseases in children. HLA-matched siblings are considered the best donors because of reduced risks of transplant-related complications and better clinical outcome. According to the National Marrow Donor Program Guidelines, the maximum amount of bone marrow harvest is limited to 20ml/kg donor's body weight. The aim of this retrospective study was to assess the optimal bone marrow harvest volume in pediatric donors needed to obtain the desired CD34+ cell count. METHODS: We reviewed medical charts of 553 pediatric (age at harvest RESULTS: 288 out of 553 donors were male. 155 (28%) were below 5 years of age at harvest, 189 (34.2%) were between 5-10 and remaining 209 (37.8%) were 10 years and above, with a median of 8.4 years (range: 0.2-17.9). Primary indication for transplant among 131 (23.7%) of our pediatric recipients were Malignant Disorders, Non-Malignant Disorders in 214 (38.7%) and Primary Immunodeficiency and Histiocytic Disorders in 208 (37.6%). GCSF priming was carried out in 219 (39.6%) donors. The minimum desired CD34+ cell count of ≥3.0X10^6 per Kg of recipient weight was reached in 517 (93.5%) harvests. Post infusion Absolute Neutrophil Counts (ANC) recovery within Day+28 was recorded among 472 (85.4%) of the transplant naïve recipients, while in 72 (13%) cases ANC never recovered and in remaining 9 (1.6%) time to recovery was beyond Day+28. ANC recovery within Day+28 was significantly associated with CD34+ cell dose of ≥3.0X10^6 per Kg of recipient weight (n=441, 93.4% vs. 31, 6.6%; P-Value 54 (9.8%) of our donors required PRBC transfusion; among whom 34 (63%) were below 5 years of age at harvest, 15 (27.8%) 5-10 years and remaining 5 (9.3%) were 10 and above (P-Value CONCLUSION: Our study confirmed that CD34 cell count were significantly higher among younger donors. The use of Higher CD34 cell dose is significantly associated with engraftment. Priming with G-CSF had significant impact on CD34+ cell count. These large data confirm the suggestion that the volume of bone marrow harvested can be decreased among younger donors without significantly changing the overall CD34 cell count. Disclosures No relevant conflicts of interest to declare.

We report the results of clinical exome sequencing (CES) on >2,200 previously unpublished Saudi families as a first-tier test. The predominance of autosomal-recessive causes allowed us to make several key observations. We highlight 155 genes that we propose to be recessive, disease-related candidates. We report additional mutational events in 64 previously reported candidates (40 recessive), and these events support their candidacy. We report recessive forms of genes that were previously associated only with dominant disorders and that have phenotypes ranging from consistent with to conspicuously distinct from the known dominant phenotypes. We also report homozygous loss-of-function events that can inform the genetics of complex diseases. We were also able to deduce the likely causal variant in most couples who presented after the loss of one or more children, but we lack samples from those children. Although a similar pattern of mostly recessive causes was observed in the prenatal setting, the higher proportion of loss-of-function events in these cases was notable. The allelic series presented by the wealth of recessive variants greatly expanded the phenotypic expression of the respective genes. We also make important observations about dominant disorders; these observations include the pattern of de novo variants, the identification of 74 candidate dominant, disease-related genes, and the potential confirmation of 21 previously reported candidates. Finally, we describe the influence of a predominantly autosomal-recessive landscape on the clinical utility of rapid sequencing (Flash Exome). Our cohort’s genotypic and phenotypic data represent a unique resource that can contribute to improved variant interpretation through data sharing.

Geographic variation and ethnicity have been implicated to influence the outcome of pediatric acute myeloid leukemia (AML). Furthermore, survival outcomes from developing countries are reported to be inferior to developed nations. We hypothesized that risk- and response-based outcome in high-income resource-rich developing countries would be comparable to developed nations as access to care and supportive measures would be similar. A total of 193 children diagnosed with de novo AML between January 2005 and December 2012 were identified, of those 175 were evaluable for outcome. Patients were stratified into low-risk (LR), intermediate-risk (IR), or high-risk (HR) groups. The complete remission (CR), early death, and induction failure rates were: 85.7%, 2.3%, and 12%; respectively. The 5-year cumulative incidences of relapse (CIR) and non-relapse mortality (NRM) were 43.1% and 9.8% respectively; overall survival (OS) was 58.8±4% and event-free survival (EFS) 40.9±4.1%. The 5-year OS for LR, IR, and HR groups were 72.0±6.9%, 59.8±6.2%, and 45.1±7.4%; respectively (p=0.003); and EFS 50.5±8.0%, 46.3±6.4%, and 23.3±6.4%; respectively (p=0.001). This study demonstrated comparable outcomes to those reported from developed countries. This suggests that utilization of risk- and response-based protocols in developing countries can overcome ethnic and geographic variation, if access to care and supportive measures were similar.

Fanconi anemia (FA) cells are characterized by genomic instability which places FA patients (pts) at risk for malignancies; leukemia and oropharyngeal/urogenital cancers. The risk of development of leukemia is theoretically eliminated after hematopoietic cell transplantation (HCT). Simultaneous presence of both host- and donor-derived cells in the recipient often referred to as mixed chimerism (MC) is observed in a large proportion of patients after HCT with non-malignant disorders. In FA patients however, MC might have a unique implication and the persistent existence of FA cells represents a management dilemma as the lingering FA cells may theoretically evolve into a malignant clone. We have studied a large population of FA patients who underwent allogeneic HCT at our institution and report here the outcome of those with MC. From January 1995 until December 2017, 163 FA pts underwent allogeneic HCT at our center; chimerism data at last contact were available on 100 pts who are the subject of this analysis. Females (51) had a mean age at HCT of 8.7 (SD:3.0, Min-Max: 2.0-14.1) years whereas in males (49) it was 8.1 (SD:3.4; Min-Max: 1.4-17.4) years (P-Value: 0.415). Donor was HLA matched family member in 78 pts, Haplo-identical family member in 17 (92 of them were bone marrow and 3 peripheral stem cells); 3 had unrelated cord blood. Total body irradiation was used in 24 pts. Median time to ANC and platelets recovery was 14 and 22 days respectively. Cumulative incidence of overall aGVHD Grade III or above was 4%. Median follow up time was 67.2±14.6 months (95% CI: 38.7-95.7) from HCT date (Min: 7.3, Max:188.1). Chimerism analysis at last follow up showed full chimerism (100%; Myeloid/lymphoid) in 46 pts; 54 had MC defined as the presence of any residual recipient cells. No statistically significant association was noted between full and MC pts in the incidence of aGvHD (P-Value: 0.331). The 10-year cumulative probability of Overall Survival (OS) was 0.904±0.042. No significant difference was observed in OS between full and MC pts (0.954±0.032 vs. 0.883±0.059, P-value: 0.943) with 4 deaths in each group. New malignancy occurred in 4 pts; 2 in each group. In full Chimerism pts: Acute Mixed Lineage Leukemia and carcinoma and in MC pts: acute myeloid leukemia and acute lymphocytic leukemia, (P-Value=1.00). Graft failure occurred in 2 pts in the mixed chimerism group vs none in the full chimerism group (P-Value=1.0). We conclude that mixed chimerism in FA pts does not appear to have an adverse effect on outcome in our follow-up period; longer follow-up time however is needed to confirm the validity of this statement. Disclosures No relevant conflicts of interest to declare.

Hematopoietic cell transplantation (HCT) remains until now the only curative modality for hematological manifestations in patients with Fanconi anemia (FA). The doses of alkylating agents used in the conditioning of this patient population before HCT are usually significantly decreased due to the genomic instability of the FA cells. FA patients with renal impairment represent a dilemma because of the need to further modify the conditioning regimen according to the degree of renal impairment to avoid additional toxicity. At our institution, we successfully transplanted three FA patients using an ultra-modified regimen.

Background: Despite the confirmed favorable prognosis of childhood t(8;21) acute myeloid leukemia (AML), recent reports suggest heterogeneity in survival outcomes in this subtype of AML may be influenced by ethnicity. Therefore, we aimed to assess the outcome of childhood t(8;21) AML in an Arab population to evaluate if survival outcomes were inferior and determine the predictive relevance of additional cytogenetic abnormalities. Methods: This multicenter retrospective study analyzed 175 de novo AML children of 14 years of age or younger consecutively diagnosed between January 2005 and December 2012. Survival outcomes were analyzed and patients with t(8;21) were stratified on the basis of karyotype into sole and additional cytogenetic groups. Results: A total of 33 (18.9%) patients had t(8;21) AML. Complete remission (CR) was achieved in 31 (93.9%) patients. The 5-year overall survival, event-free survival, cumulative incidence of relapse (CIR), and remission death rates were 59.9 ± 9.2, 45.6 ± 9.1, 36.4, and 9.1%, respectively. Despite the administration of hematopoietic stem-cell-transplant salvage therapy in first relapse, five out of 11 (45.5%) relapsed patients died of disease. Subanalysis of sole vs. additional cytogenetic abnormalities revealed no significant difference in outcome. Conclusion: In the present study, childhood t(8;21) AML was associated with inferior survival and resistance to salvage therapy compared to reports from international groups. The inferior outcomes were unrelated to additional cytogenetic abnormalities. Further detailed genetic studies are warranted to unmask the biological and clinical differences between racial/ethnic groups. Given the high CR rate of childhood t(8;21) AML, further modification of postremission therapy to improve the CIR rate is needed.

Background. Inherited bone marrow failure syndromes (IBMFSs) comprise a genetically heterogeneous group of diseases with hematopoietic failure and varying degrees of physical malformations. The diagnosis of an IBMFS and categorizing the specific syndrome critically impact on clinical care; however, these are commonly challenging and rely on genetic testing. Since over 80 genes have been associated with IBMFSs and might be affected by different types of DNA aberrations, the best strategy to establish a diagnosis in a timely and cost effective manner is unknown. The aims of this study were to evaluate the role of genome-wide copy number variant (CNV) analysis in unraveling causal genetic alterations in IBMFS patients with unknown genotype and determine whether correlation exists between large CNVs and more severe phenotype. Methods. Patients from the Canadian Inherited Marrow Failure Registry (CIMFR) who were genetically investigated were included in this analysis. Genetic and clinical data were extracted and analyzed. Mann-Whitney test and Fisher's exact test were used to assess statistical significance. Results. Among 328 patients from the CIMFR who underwent molecular investigation, a causal genotype was identified in 185 cases (56.4%). 69 patients had genome-wide CNV analysis by SNP/CGH arrays, among which ten (14.5%) had positive results. In four out of ten cases who were genotyped by SNP/CGH array, genome-wide CNV analysis was critical for establishing the diagnosis. Among 308 patients who were tested for nucleotide-level mutations by either targeted gene analysis or next generation sequencing panels, casual mutations were found in 169 (54.9%). Three patients had compound heterozygosity for a CNV and nucleotide-level mutation. To determine whether large deletions are correlated with more severe phenotype we included nine additional patients with causal CNVs whose genotype was identified by MLPA (n=1), targeted FISH (n=1), DNA-qPCR analysis (n=1), Southern blotting (n=1) or metaphase cytogenetics (n=5). The causal CNVs among patients in our cohort ranged from 0.02 to 145.5 Mb in size. The most common disease associated with causal CNVs was Diamond-Blackfan anemia (four patients). Patients with CNVs tended to have significantly more non-hematological organ system involvement (p=0.03), developmental delay (mean=56% vs. 28%, p=0.03) and short stature (mean=67% vs. 40%, p=0.04) than patients with nucleotide-level mutations. The difference remained significant when we compared all patients with mutations that are predicted to result in truncation or lack of protein from the respective allele (large CNV, nonsense, and indel/ frameshift) to patients with mutations that are predicted to be hypomorphic or affect function (splicing, indel/ inframe and missense). There was no correlation between CNVs and the severity of the hematological disease. Conclusions. Most patients with IBMFSs have nucleotide-level mutations. However, a significant proportion of patients without such mutations have large CNVs that are not efficiently detected by current nucleotide-level testing methods. Therefore, genome-wide CNV analysis should be considered in IBMFS cases, where nucleotide-level sequencing does not reveal the causal mutation. Patients with IBMFSs and large CNVs had more non-hematological organ system involvement, a higher prevalence of developmental delay and short stature. This might be related to an additional impact of the CNVs on other genes close to the affected IBMFS gene or the severe damaging effect of the CNVs. Disclosures Lipton: Teva: Consultancy, Research Funding; Ariad: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Novartis Pharmaceuticals: Consultancy, Research Funding.

Background/Objectives: Diamond Blackfan anemia (DBA) is an inherited disorder characterized by chronic hypoproductive anemia, physical malformations, and an increased risk of malignancies. At least 12 DBA genes have been identified, which include various ribosomal protein genes and the transcription factor GATA1. The aims of our study were (1) to identify the mutation spectrum of DBA patients, utilizing a cohort of patients enrolled on the Canadian Inherited Marrow Failure Registry (CIMFR) and (2) to determine whether specific hematological abnormalities, malformations, and outcomes are associated with specific mutations. Methods: Patients were enrolled on the CIMFR, which is a multicenter cohort study of inherited bone marrow failure syndromes (IBMFS). Genetic testing was performed using one or more of the following tests: Sanger sequencing, next generation sequencing (NGS) DBA gene panel, a comprehensive NGS IBMFS gene panel developed in our laboratory, or comparative genetic hybridization (CGH). Severity of the hematological disease was dichotomized according to a patient's requirement for chronic treatment: those who were maintained on corticosteroids, blood transfusions, or received a hematopoietic stem cell transplantation were considered to have a more severe phenotype than those who did not require hematological treatment. Chi-square tests with a Fisher's exact test correction were used to compare genetic groups with at least 5 patients on observed phenotypes. Results: 71 patients with DBA have been enrolled in our registry. A causal mutation has been identified in 36 of these patients, with the following rates: RPS19 (n=11), RPL11 (n=7), RPL5 (n=6), RPS26 (n=5), RPL35a (n=2), RPS24 (n=2), and one of each RPS7, RPS29, RPS17. Remarkably, a substantial number of patients in our population-based cohort (19.4%) had mild hematological phenotype requiring no therapy. Patients with RPL11 mutations tended to have a less severe DBA phenotype, while patients with RPS19 mutations tended to have a more severe phenotype (p=0.04). In terms of non-hematological malformations, we found no differences in cardiac, stature and craniofacial malformations across the groups compared (all p>0.1). However, patients with RPL5 mutations had significantly more hand malformations (p=0.02), and patients with RPS26 mutations had more genitourinary malformations (p=0.04). To control for the impact of mutation severity on the observed phenotype, we compared the prevalence of mutations that are predicted to result in truncated or lack of protein from the respective allele (large copy-number variation, nonsense, or indel frameshift) to mutations that are predicted to be hypomorphic or affect function (splicing, indel/inframe and, missense) between mutation categories. There were no differences among genetic groups in the severity of their mutations (p=0.58). Conclusions: Mutations in a wide spectrum of ribosomal protein genes underlie DBA cases in Canada, which approximate those observed by other registries in Western countries. Patients with DBA caused by RPL11 mutations tended to have a milder hematological phenotype, while patients with RPS19 mutation tended to have a more severe phenotype. Mutations in RPS26 and RPL5 are associated with genitourinary and hand malformations, respectively. Our findings may help improve counseling of DBA patients and their family. Future studies are needed to replicate our results and determine whether these findings can help personalize care. Disclosures Lipton: Ariad: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Teva: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Novartis Pharmaceuticals: Consultancy, Research Funding.

Background and Objectives. Phenotypic overlap among the inherited bone marrow failure syndromes (IBMFSs) frequently limits the ability to establish a diagnosis based solely on clinical manifestations. Since a large number of IBMFS genes (>70) have been identified, genetic testing is often prolonged and costly. Correct diagnosis, care and counseling often depend on identifying the mutated gene. Thus time-efficient and cost-effective strategies for genetic testing are essential. The aims of this study were to develop and evaluate the application of a next generation sequencing (NGS) IBMFS Gene Panel assay for genetic testing of patients with previously characterized categories of IBMFSs (e.g. Fanconi anemia and Diamond Blackfan anemia) but unknown genotype, as well as patients with unclassified IBMFSs. Methods. We designed a NGS assay to test a comprehensive panel of 72 known IBMFS genes. Genomic DNA from patients enrolled on the Canadian Inherited Marrow Failure Registry was analyzed using the Haloplex technology and Illumina Seq2000 platform. The average gene coverage was 99.12%. SureCall program was used to align, map, and identify variants. Polyphen, Sift and MutationTaster were used to predict the effect of variants on the protein. Human Splicing Finder program was used to analyze effect of splicing. The assay was validated by detecting all 50 mutations and polymorphic variants that were previously found by Sanger sequencing in 31 patients. Results. A total of 158 patients with unknown mutations were studied. Among 75 patients with known categories of IBMFSs but unknown genotypes, we found deleterious mutations in 43 patients (57.3%). These categories included Diamond Blackfan anemia, Fanconi anemia, dyskeratosis congenita, Shwachman-Diamond syndrome, TAR syndrome, familial thrombocytopenia and Kostmann/severe congenital neutropenia. Among 83 patients with unclassified IBMFSs, we found deleterious mutations and established the diagnosis in 16 patients (19.2%). Established diagnoses included dyskeratosis congenita, Diamond-Blackfan anemia, myelokathexis, GATA2-associated familial MDS, WAS-associated severe congenital neutropenia, G6PC3-associated severe congenital neutropenia, MYH9-associated disorder, MASTL-associated disorder and Wiskott-Aldrich syndrome. All identified mutations were validated. The assay allowed identification of mutant genes that had not been previously reported to be associated with the patient phenotypes in two cases. The assay led to amendment of established diagnoses in two other cases. The assay results directed a change in clinical care in multiple cases, including implementation of cancer surveillance program and consideration for prenatal diagnosis. The cost of the NGS was $470/patient compared to $4643/patient among those who underwent genetic testing by Sanger sequencing during the tenure of the study. Conclusion. Our novel assay is a rapid, accurate, and cost saving strategy for genetic investigation of patients with IBMFSs. It can identify mutations in classified and unclassified IBMFSs with high level of sensitivity and precision. Disclosures No relevant conflicts of interest to declare.

Background The Immature Platelet Fraction (IPF) is a novel parameter available on the Sysmex XE-Series Hematology analyzers. It can be expressed as both IPF percent (IPF %) and absolute IPF count (AIPF#). It has been shown that IPF% is higher in Immune Thrombocytopenia (ITP) than in the normal population, and correlates with bone marrow platelet production or thrombopoiesis. Objectives To evaluates the utility of the IPF parameters to predict treatment response or recovery in pediatric ITP patients. Method This is a retrospective, single institution study performed at a 165 bed tertiary care pediatric hospital (Children's Hospital of Eastern Ontario, Ottawa, Canada). We reviewed the medical charts and electronic databases of all patients with ITP who had measured IPF parameters between June 2011 and June 2013. The standard definitions and terminology of the International Working Group were used. Patient age, phase of ITP at the time of the study (acute, persistent, and chronic), initial platelet count, IPF%, AIPF#, and type of therapy given (including observation alone) were recorded. For patients who responded to treatment or had spontaneous recovery without treatment, we analyzed the platelet count, IPF% and AIPF# on subsequent CBCs, then looked at the course of IPF% during platelet count recovery. Comparisons between groups were performed using Kruskal-Wallis tests or Mann-Whitney tests, as appropriate. Association between measured blood parameters was measured using the Spearman correlation coefficient. Within-patient Spearman correlations were also used to study the association between IPF% and platelet counts during recovery. The combined significance of these associations was determined using Stouffer’s method. Results Conclusion IPF measurements are easily available parameters that are useful in the management of ITP in pediatric patients. This study suggests the use of AIPF# as a predictive factor for recovery in pediatric ITP patients with and without treatment, and IPF% as a predictive factor for early recovery. Disclosures: No relevant conflicts of interest to declare.

Background Immune thrombocytopenia (ITP) is characterized by impaired megakaryocte production and maturation, as well as premature platelet destruction. The effect of this disease on platelet production is not clear. The Immature Platelet Fraction (IPF) is a novel parameter available on the Sysmex XE-Series Hematology analyzers. It can be expressed as both IPF percent (IPF %) and absolute IPF count (AIPF#). It has been shown that IPF% is higher in Immune Thrombocytopenia (ITP) than in the normal population, and is an indicator of bone marrow platelet production or thrombopoiesis. Objectives To characterizes the IPF parameters in pediatric patients with ITP at diagnosis and during different phases of the disease (newly diagnosed, persistent, and chronic). Method This is a retrospective, single institution study performed at a tertiary care pediatric hospital. We reviewed the medical charts and electronic databases of all patients with ITP who had measured IPF parameters between June 2011 and June 2013. The standard definitions and terminology of the International Working Group were used. Patient age, phase of ITP at the time of the blood test (newly diagnosed, persistent, and chronic), initial platelet count, IPF%, AIPF#, and type of therapy given (including observation alone) were recorded. We then compared the platelet count, IPF%, and AIPF# between the ITP phases at the time of initial CBC and looked at the relationship between the platelet count and IPF%. Comparisons between groups were performed using Kruskal-Wallis tests or Mann-Whitney tests, as appropriate. Association between measured blood parameters was measured using the Spearman correlation coefficient. Results • We included 47 patients; mean age was 9.4 years (1-18). At the time of the study,16 (34%) patients had newly diagnosed ITP (0-3 Months), 6 (12.8%) had persistent ITP (3-12 Months), and 25 (53.2%) had chronic ITP (>12 Months) • The initial platelet count was lower in newly diagnosed patients at 6x109/L (IQR 2-8), compared to patients with persistent ITP (16x109/L, IQR 7-24.5) and chronic ITP (30x109/L, IQR 17.5-53.5) (p=0.000). • IPF% was significantly higher in newly diagnosed ITP at 23.2% (IQR 19.6-27.8) compared to persistent ITP (17.4%, IQR 10.6-23.5) and chronic ITP (12.8%, IQR 7.3-17.1, p=.001) (figure 1A). In contrast, AIPF# was significantly lower in newly diagnosed ITP (1.1x109/L, IQR 0.44-1.5) compared to persistent ITP (1.7x109/L, IQR 1.1-4.4) and chronic ITP (3.5x109/L, IQR 2.0-4.5, p • IPF% correlated negatively with platelet counts for all patients (P=0.001) and this correlation was significantly more prominent in chronic ITP (figure 2). Conclusion IPF parameters may be useful in understanding the mechanism of ITP through the evolution of the disease. From the time of diagnosis of ITP through progression to chronic ITP, there is a steady decrease in IPF% and increase in AIPF# .The high IPF% in the newly diagnosed setting suggests that megakaryocytes are still active, whereas the lower IPF% in chronic ITP indicates inhibition of megakaryopoiesis or a different underlying pathophysiology. This may have important clinical implications when considering TPO receptor agonist therapy. Download : Download high-res image (40KB) Download : Download full-size image Download : Download high-res image (40KB) Download : Download full-size image Download : Download high-res image (19KB) Download : Download full-size image Disclosures: No relevant conflicts of interest to declare.