Matched unrelated donor transplantation versus haploidentical transplantation with post-transplant cyclophosphamide in children with acute myeloid leukemia: a PDWP-EBMT study.

In children with acute myeloid leukemia (AML) who lack an HLA identical sibling, the donor can be replaced with an HLA matched unrelated donor (MUD) or a haploidentical donor (haplo). We compared outcomes of patients <18 years with AML in first and second complete remission (CR1 and CR2) undergoing a hematopoietic stem cell transplantation (HCT) either with a MUD with anti-thymocyte globuline (ATG) (n=420) or a haplo HCT with PT-CY (n=96) after a myeloablative conditioning regimen (MAC) between 2011 and 2021, reported to EBMT. A matched pair analysis was performed to adjust for differences among groups. The final analysis was performed on 253 MUD and 95 haplo-HCTs. In the matched cohort, median age at HCT was 11.2 and 10 years and median year of HCT was 2017 and 2018, in MUD and haplo- HCT recipients, respectively. The risk of grade III-IV aGvHD was significantly higher in the haplo group (HR=2.33, 95%CI1.18-4.58, p=0.03). No significant differences were found in 2 years overall survival (OS; 78.4%vs71.5%; HR 1.39, 0.84-2.31, p=0.19), leukemia-free-survival (LFS; 72.7%vs69.5%; HR1.22, 0.76-1.95, p=0.41), CI of relapse (RI; 19.3%vs19.5%; HR=1.14, 0.62-2.08, p=0.68) non-relapse-mortality (NRM; 8%vs11%; HR=1.39, 0.66-2.93, p=0.39) and graft versus host free-relapse free survival (GRFS; 60.7%vs54.5%, HR=1.38, 0.95-2.02, p=0.09) after MUD and haplo-HCT respectively. Our study suggests that haplo-HCT with PT-CY is a suitable option to transplant children with AML lacking a matched related donor.

Is Mixed Chimerism Post-allogeneic Hematopoietic Stem Cell Transplantation in Pediatric Acute Lymphoid Leukemia a Prognostic Factor for Relapse?

Hematopoietic stem cell transplantation (HSCT) has been considered curative for children with high-risk acute leukemia (ALL), offering better survival. Short tandem repeat has been used as a marker of chimerism status after HSCT. The appearance of recipient cells >1% post-allogeneic stem cell transplant is defined as mixed chimerism (MC). Chimeric studies post-HSCT are dynamic. This study aimed to investigate the significance of recipient cells in post-HSCT pediatric ALL patients as a predictor of relapse of their primary disease. The rate of MC was 51.4% (19 out of 37 recipients). It was 48.6% (n = 18) during Day+100 and 12.9% (4 out of 31 recipients) during post-Day+100 follow-up until two years. No significant association was noted between MC and all grade overall acute graft-versus-host disease. A mortality rate of 35.1% (n = 13) and a median follow-up of 56.9 months (95% CI: 39.7-74.2) were observed for all but four (16.7%) of the survivors in remission. Regarding causes of death, transplant-related mortality was recorded in only 2 of 13 expired patients (15.4%); both succumbed to sepsis. No significant association was found between MC and primary causes of death. The cumulative probability of five-year overall survival and event-free survival was not found to be statistically significantly different for MC (≤1.0% vs. > 1.0%). In conclusion, our data did not show MC testing alone as an effective prognostic marker for detecting relapse; molecular and flow cytometric analyses should be considered in children with ALL post-HSCT for monitoring relapse.

Clofarabine in Pediatric Acute Relapsed or Refractory Leukemia: Where Do We Stand on the Bridge to Hematopoietic Stem Cell Transplantation?

Background: Despite pronounced improvement in overall survival (OS) in pediatric leukemia, a proportion of patients continue to suffer from lack of response or relapse, and the management of such patients is exceedingly difficult. Immunotherapy and engineered chimeric antigen receptor (CAR) T-cell therapy have shown promising results in the course of relapsed or refractory acute lymphoblastic leukemia (ALL). However, conventional chemotherapy continues to be utilized for re-induction purposes whether independently or in combination with immunotherapy. Methods: Forty-three pediatric leukemia patients (age < 14 years at diagnosis) consecutively diagnosed at our institution and got treated with clofarabine based regimen at a single tertiary care hospital between January 2005 and December 2019 were enrolled in this study. ALL comprised of 30 (69.8%) patients of the cohort while the remaining 13 (30.2%) were with acute myeloid leukemia (AML). Results: Post-clofarabine bone marrow (BM) was negative in 18 (45.0%) cases. Overall clofarabine failure rate was 58.1% (n = 25) with 60.0% (n = 18) in ALL and 53.8% (n = 7) in AML (P = 0.747). Eighteen (41.9%) patients eventually underwent hematopoietic stem cell transplantation (HSCT); 11 (61.1%) were from ALL group and remaining seven (38.9%) were AML (P = 0.332). Three- and 5-year OS of our patients was 37.7±7.6% and 32.7±7.3%. There was a trend of better OS for ALL patients compared to AML (40.9±9.3% vs. 15.4±10.0%, P = 0.492). Cumulative probability of 5-year OS was significantly better in transplanted patients (48.1±12.1% vs. 21.4±8.4%, P = 0.024). Conclusions: Though almost 90% of our patients proceeded to HSCT with complete response post-clofarabine treatment, yet clofarabine-based regimens are associated with the significant burden of infectious complications and sepsis-related deaths.

Can the bone marrow harvest volume be reduced safely in hematopoietic stem cell transplantation with pediatric sibling donors?

Background: Reduced harvest volumes in pediatric donors appear to have the potential to reduce donor-associated risks while maintaining engraftment in recipients; however, the allowable harvest volume reduction remains undefined. Methods: We retrospectively analyzed the data pairs of 553 bone marrow (BM) harvests from pediatric (age at harvest <18 yr) sibling donors and clinical outcomes of 553 pediatric (age at infusion <14 yr) transplant-naïve recipients to assess the optimal BM harvest volume needed from pediatric donors to obtain the desired CD34+ cell count (≥3.0×106 cells per kg of recipient weight), and to study its impact on the clinical outcomes of transplantation in pediatric recipients. Results: The minimum desired CD34+ cell count of ≥3.0×106 per kg of recipient weight was achieved for 506 (95.3%) of donor-recipient pairs. The median CD34+ cell yield was 6.4×106 per kg of recipient weight (range, 1.2‒33.8×106) in donors younger than 5 years old at harvest, 4.7×106 (range, 0.3‒28.5×106) in donors aged 5‒10 years and 2.1×106 (range, 0.3‒11.3×106) in donors older than 10 years (P<0.001). Conclusion: The infused CD34+ cell dose (×106 cells/kg of recipient weight) had no impact on GRFS; however, a CD34+ cell dose of ＞7×106 cells/kg of recipient weight did not improve hematopoietic recovery.

Outcome of pediatric chronic myeloid leukemia with management focusing on the monitoring of BCR-ABL fusion gene transcript levels.

Background and objective: Clinical, laboratory and outcome data were reviewed for pediatric patients who were diagnosed with chronic myeloid leukemia (CML) and managed at two tertiary care hospitals in Saudi Arabia, between January 2011 and December 2017 to assess the response to tyrosine kinase inhibitors (TKI) focusing on the monitoring of BCR-ABL fusion gene transcript levels and to look at the overall outcome. Methods: CML patients were identified based on the cytogenetic and molecular results. Results: Twelve pediatric patients diagnosed with CML at a median age of 8.4 year; treated with TKI as first-line therapy, 11 (91.7%) patients were started with imatinib (first-generation TKI), while one received dasatinib (second-generation TKI) due to his three-way Philadelphia chromosome sensitivity. Eight patients (72.7%) starting on imatinib were switched to dasatinib (six patients due to drug resistance, and two patients due to intolerance of Imatinib) and two patients (25%) of whom had already achieved major molecular response (MMR) on Imatinib. Response rate to imatinib in terms of achieving MMR as first-line therapy was achieved in five out of 11 patients (45.5%) and only three of them continued to maintain their MMR. Six out of eight patients who were switched to dasatinib achieved MMR. Two patients underwent hematopoietic stem cell transplant (SCT): one due to blast crisis and one due to the side effects of TKI. With a median follow-up time of 78 months (range, 40.5-108), all of our patients were alive at last update. Conclusion: We report an excellent outcome with an overall survival (OS) of 100% at 5-year and disease-free survival (DFS) of 91.7% (8.0%). All our patients achieved MMR and only one patient had loss of MMR on follow-up. Eight patients (66.7%) achieved complete molecular response (CMR).

Hematopoietic Stem Cell Transplantation Stabilizes Cerebral Vasculopathy in High-Risk Pediatric Sickle Cell Disease Patients: Evidence From a Referral Transplant Center.

Background: Severe sickle cell disease (SCD) can present with different vaso-occlusive manifestations with cerebral vasculopathy (CV) as one of the most serious complications. Hematopoietic stem cell transplant (HSCT) is the ultimate therapy for this complication. The aim of this study was to assess the outcome and impact of HSCT on severe SCD patients with CV complications. Methods: Twenty-five consecutive transplants-naive pediatric SCD patients with CV complications underwent HSCT at our institution between 1993 and 2015, using bone marrow as stem cells source from fully match related donors were included. Neurologic evaluation was done both clinically and radiologically before transplantation and regularly following the HSCT. Results: With a median follow-up of 52.2 ± 5.8 months, the cumulative probability of overall survival (OS) at 3 years was 92.0% and event-free survival (EFS) was 88%. Significant neurologic improvements were observed in most of the patients clinically. Different neurologic complications were assessed. The neurologic manifestations before and after HSCT were hemiparesis (11, 1), seizures (13, 8), focal neurologic deficit (4, 2), loss of conscious (2, 1) headache (6, 1), and psychological symptoms (5, 2). Post-HSCT radiological imaging was done in 15 patients, which showed stabilization of CV among all. Conclusions: Allogeneic HSCT in patients with severe SCD presenting with CV complications including moyamoya vasculopathy showed favorable outcome with significant clinical neurologic improvement and stabilization of the disease. None of the patients with severe vasculopathy underwent neurological vascular by-pass surgery prior to HSCT.

Outcomes of blood and marrow transplantation in children less than 2-years of age: 23 years of experience at a single center.

Objectives: Allogeneic hematopoietic cell transplantation (Allo-HCT) is a curative option for children with various malignant and non-malignant diseases. Most reports studied all age groups amongst children. Herein we analyzed our data in children transplanted at or less than 2-years of age. Patients and methods: We reviewed medical charts of 618 patients who underwent 666 transplantation at our center between 1993 and 2015. There were 340 boys and 278 girls. Median age was 0.7 years (range 0.04-2). Stem cell source was bone marrow (BM) in 492 (73.9%), unrelated umbilical cord blood (UCB) in 161 (24.2%) followed by peripheral blood stem cell (PBSC) in 13 (2%) patients. Matched siblings were the most common donors (n = 356, 53.5%), followed by unrelated (n = 161, 24.2%) with haploidentical family member donors in 29 (4.4%) transplants. Disease groups were categorized as benign hematology (Thalassemia, Fanconi, Aplastic anemia etc.), benign neoplasm (Langerhans cell histiocytosis, Hemophagocytic Lymphohistiocytosis etc.), non-neoplasms (metabolic disorders, immunodeficiency disorders etc.) and Leukemia/lymphomas (myeloid and lymphoid malignancies etc.). Results: Cumulative incidence of acute GvHD (I-IV) was 31.5% (n = 210) and grade III-IV GvHD was 8.7% (n = 58). At median follow-up of 115.1 months, the cumulative probability of overall survival (OS) at 5 years was 70.0% ± 1.9%. Our mortality rate was 31.2% (n = 193). The five-year OS was significantly better in patients transplanted for benign hematological disorders (P = .001). Patients transplanted using BM/PBSC as source of stem cells fared significantly better compared to those in which CB was used (P<.001). Post-transplant graft failure remains the leading cause requiring further transplants in this age group. In conclusion, the cumulative probability of OS at 5 years was about 70.0% for all with an OS of 61% in our haploidentical recipients. Conclusion: Analyzing our institutional data over time has enabled us to develop tentative strategies to minimize transplant related toxicities in very young children who are candidates for allo-HCT.

Pediatric high risk neuroblastoma with autologous stem cell transplant - 20 years of experience.

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.

Does Mixed Chimerism After Allogeneic Hematopoietic Cell Transplantation in Pediatric Patients With Fanconi Anemia Impact on Outcome?

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.

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 Outcome in Patients with Fanconi Anemia Undergoing T Cell-Replete Mismatched Related Donor Hematopoietic Cell Transplantation Using Reduced-Dose Cyclophosphamide Post-Transplantation.

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.

Identifying Prognostic Factors That Influence Outcome of Childhood Acute Myeloid Leukemia in First Relapse in Saudi Arabia: Results of the Multicenter SAPHOS Study.

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.

Successful hematopoietic cell transplantation in Fanconi anemia patients with renal impairment using ultra-reduced doses of cyclophosphamide and fludarabine.

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.

Clinical characteristics and outcome of childhood acute promyelocitic leukemia (APL) in Saudi Arabia: a multicenter SAPHOS leukemia group study.

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.

Treatment results in children with myeloid leukemia of Down syndrome in Saudi Arabia: A multicenter SAPHOS leukemia group study.

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.

Clinical characteristics and outcome of childhood de novo acute myeloid leukemia in Saudi Arabia: A multicenter SAPHOS leukemia group study.

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.

Improving diagnostic precision, care and syndrome definitions using comprehensive next-generation sequencing for the inherited bone marrow failure syndromes.

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.