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Acute myeloid leukemia (AML) has an aggressive course and a historically dismal prognosis. For many patients, hematopoietic stem cell transplantation (HSCT) represents the best option for cure, but access, utilization and health inequities on a global scale remain poorly elucidated.To describe patterns of global HSCT use in AML for a better understanding of global access, practices, and unmet needs internationally.Estimates of AML incident cases in 2016 were obtained from the Global Burden of Disease (GBD) 2019 study. HSCT activities were collected from 2009-2016 by the Worldwide Network for Blood and Marrow Transplantation (WBMT) through its member organizations. The primary endpoint was global and regional use (number of HSCT) and utilization of HSCT (number of HSCT/ number of incident cases) for AML. Secondary outcomes included trends from 2009 to 2016 in donor type, stem cell source and remission status at time of HSCT.Global AML incidence has steadily increased, from 102,000 (95% uncertainty interval (UI): 90,200-108,000) in 2009 to 118,000 (104,000-126,000) in 2016 (+16.2%). Over the same period, a +54.9% increase from 9,659 to 14,965 HSCT/year was observed globally, driven by an increase in allogeneic (+64.9%) with a reduction in autologous (-34.9%) HSCT. While the highest numbers of HSCT continue to be performed in high-resource regions, the largest increases were seen in resource-constrained regions [+94.6% in Africa/East Mediterranean Region (AFR/EMR); +34.7% in America-Nord Region (AMR-N)]. HSCT utilization was skewed towards high-resource regions [in 2016: AMR-N 18.4%, Europe (EUR) 17.9%, South-East Asia/Western Pacific Region (SEAR/WPR) 11.7%, America-South Region (AMR-S) 4.5% and AFR/EMR 2.8%]. For patients70 years of age, this difference in utilization was widened; AMR-N had the highest allogeneic utilization rate, increasing from 2009 to 2016 (30.6% to 39.9%) with continued low utilization observed in AFR/EMR (1.7% to 2.9%) and AMR-S (3.5% to 5.4%). Across all regions, total HSCT for AML in 1HSCT remains a central curative treatment modality in AML. Allogeneic HSCT for AML is rising globally but there are marked variations in regional utilization and practices, including types of graft source. Resource-constrained regions have the largest growth in HSCT use, but utilization rates remain low with a predilection for familial related donor sources and are typically offered in CR1. Further studies are necessary to elucidate the reasons, including economic factors, to understand and address these health inequalities and improve discrepancies in use of HSCT as a potentially curative treatment globally.

Background A significant proportion of patients with acute myeloid leukemia (AML) will either be refractory to initial chemotherapy or will suffer refractory relapse. The role of allogeneic transplantation (SCT) in active disease is contentious. There is a growing body of literature that sequential chemotherapy, pioneered by the German FLAMSA regimen, followed by RIC SCT is a safe and efficacious modality in these patients, and there have been numerous modifications of this regimen, especially as amsacrineis not widely available. Fludarabine, cytarabineand and etoposide (VP16) (FLAV) have been reported as an effective salvage regimen. Here we report on single center outcomes of a variation of the FLAMSA regimen, substituting amsacrine for etoposide with mainly myeloablative conditioning. Methods Patients were offered this regimen if fit for allogenic HSCT and had AML which is refractory to two cycles of chemotherapy or refractory to one cycle and considered at high risk for complication with second cycles. Patients with MDS received this regimens if eligible for transplant with high or very high risk cytogenetics. All patients received cytoreductive chemotherapy consisted of fludarabine 30mg/m2/day x 4 days, Cytarabine 2g/m2/day x 4 days, etoposide 100mg/m2/day x 3days, commenced simultaneously. After 3 days of rest, conditioning chemotherapy consisted of fludarabine 30mg/m2 x 2 days and and IV busulfan 0.8mg/m2 q 6 hours; the number of busulfan doses varied between 8 - 12, depending on patient comorbidity. All patients received 2 doses of ATG at 2.5mg/m2/day on day -3 and -2. All patients received GCSF mobilized peripheral blood hematopoietic cells. Post-transplant GVHD prophylaxis consist of CsA and MMF. CsA was tapered from day+60 and stopped at day +90 in the absence of GVHD. MMF was discontinued between day +30 and day +40. Donor lymphocyte infusions were collected for planned prophylactic DLI. Results Twenty six patients received FLAV-SCT between March 2014 and July 2019. The median age was 38 (14-60); 16 (62%) female. Overall 12 (46%) pts had de novo AML, 10 (39%) pts had secondary or therapy related AML and 4 (15%) pts had MDS. Fourteen (54%) pts had adverse risk cytogenetics include 8 (31%) pts had complex or monosomal karyotype. Patients' characteristics are summarized in Table 1. All patients had active disease prior to FLAV-SCT. The median time for ANC and platelet engraftment was 14 (10 - 42) days and 17 (10 - 52) days respectively. Day 30 assessment shows CR in 16 (61%) pts and CR/CRi in 17 (65%) pts. Outcomes are summarized in Table 2. Three patients (12%) developed veno-occlusive disease. Acute GVHD grade II-IV and III-IV occurred in 9 (35%) pts and 2 (8%) pts respectively. Three (12%) patients developed chronic GVHD. Cumulative incidence of NRM at 100 days and 2 years was 8% and 12% respectively. The median OS for all pts was 5.2 months with 2 years rate of 32% (15 - 50). Among responders, the median OS and RFS were 19.2 months and 8.7 months, 2y-OS and RFS were 47% and 25%, respectively (Figure 1). Conclusion Our result demonstrates that transplant is an effective therapeutic modality in this very high risk refractory AML/MDS patients. Sequential chemotherapy (FLAV) followed by SCT with busulfan at myeloablative dose is tolerable with an acceptable toxicities and encouraging results. Figure 1 Figure 1. Disclosures Chaudhri: Novartis: Honoraria; Abbvie: Honoraria; Astra Zeneca: Honoraria. Alzahrani: King Faisal Specialist Hospital and Research Centre: Current Employment; Novartis: Consultancy, Honoraria; Bayer: Consultancy, Honoraria, Speakers Bureau; Sobi: Consultancy, Honoraria, Speakers Bureau; Pfizer: Consultancy, Honoraria, Speakers Bureau.

Introduction:Acute kidney injury (AKI) and chronic kidney disease (CKD) affect 10-70% of transplant recipients. Onset of kidney injury varies from days to months or years after transplantation. Kidney injury may be caused by multiple factors. Long-term data on cyclosporine induced nephrotoxicity post HSCT are limited. It is unclear if cyclosporine induced nephrotoxicity at early phase post HSCT will impact long term renal function. The objective of this study is to evaluate the progression of renal function in allogeneic hematopoietic stem cell transplant (HSCT) patients, before, during and after cyclosporine therapy. Methods:This is a retrospective single arm cohort study evaluating the impact of cyclosporine on renal function in patients who underwent allogeneic HSCT from 2003 through 2013. Patients age≥ 14 years who underwent allogeneic HSCT and received cyclosporine as graft-versus-host disease (GVHD) prophylaxis and alive two years post HSCT without disease relapse or GVHD were included in the study. Primary outcome was the change in serum creatinine and estimated creatinine clearance. Delta creatinine (baseline creatinine - creatinine on day 25, day 100, day 180, year 1 and year 2 post HSCT) was used to calculate the change in the serum creatinine and estimated creatinine clearance. Estimated creatinine clearance was calculated using Cockcroft and Gault formula (CG) for patients aged ≥ 18 years. Schwartz formula was used to estimate creatinine clearance for patients aged ≥ 14 years till 18 years. The secondary outcome was the incidence of acute kidney injury. AKI was defined as per RIFLE criteria. The severity grades were defined on the basis of the changes in serum creatinine. CKD was defined if estimated glomerular filtration rate (GFR) Results: Out of 912 patients who underwent allogeneic HSCT from 2003 to 2013, 121 patients were included who met the inclusion criteria listed above in the method section (Figure 1). The majority of patients were males (55%) with sever aplastic anemia as primary disease (31%). Mean baseline serum creatinine was 52±16 µmol/l, mean baseline estimated creatinine clearance was 116±58 ml/minute per 1.73 m2 (Table 1). Mean duration of cyclosporine levels monitoring was 232±180 days. Serum creatinine increased from the baseline at day 25, day 100, day 180, 1 year and 2 years post HSCT (Mean± SD; 45.7 ±39, 66.2 ±45.9, 37.8±27.1, 31.9±22.55, 28±22.5 µmol/l, respectively) (Figure 2). This translated into reductions in the estimated creatinine clearance at day 25, day 100, day 180, 1 year and 2 years post HSCT (Mean± SD; -61.6±51 , -89.6 ±55.7,-67. ±55.34,-62.5±55.4,-57.6±56.ml/minute per 1.73 m2, respectively) (Figure 3). The highest incidence of AKI was at day 100 post HSCT in the included patients. 40% of them had supratherapeutic cyclosporine levels. There was association between developing acute kidney injury at day 100 and CKD at 2 years post HSCT, 23% of the included patients had acute kidney injury and 13 % of them found to have CKD at 2 years post HSCT as illustrated table 2. Conclusion:Our study demonstrated that cyclosporine represents a primary risk factor for progression of renal impairment in hematopoietic stem cell transplant recipients particularly in those who developed acute kindly injury at 100 days. Disclosures No relevant conflicts of interest to declare.

Introduction: Fanconi Anemia (FA) is an autosomal recessive disorder characterized by bone marrow failure (BMF), constitutional anomalies and high risk of developing cancer. Distinguishing FA from severe aplastic anemia (SAA) can be challenging especially in asyndromic patients. We undertook a clinical and laboratory cohort study of adolescent and young adult (AYA) patients with a diagnosis of FA treated at our institution to characterize the clinical features in our population, and conducted a prospective translational study to explore integration of a genomic and proteomic approach for improved diagnosis and molecular characterization of FA. Methods: Data on FA patients was obtained from an institutionally approved BMF database and hematopoietic stem cell transplant (HSCT) database. Further data was obtained from a register of chromosomal breakage (CB) analysis results. Index cases were identified if they were older than 14 years of age at the time of diagnosis or under the care of adult hematology with a clinical diagnosis of FA based on the presence of BMF and abnormal CB, or clinical phenotype with the presence of homozygous FA related genes. Family pedigrees were constructed based on history. In addition, patients presenting with BMF were enrolled onto an institutionally approved study investigating proteomic biomarkers and genomics of BMF syndromes. Consented peripheral blood samples and/or extracted DNA were subject to either panel based next generation sequencing (NGS) testing as part of the Saudi Genome Project or subjected to whole exome sequencing (WES) by external lab. For proteomic analysis, peripheral blood plasma (PBP) samples from 6 patients with FA, 10 SAA patients and 7 normal controls were subjected to expression proteomics using liquid chromatography tandem mass spectrometry (LC-MS/MS). Result: Patients and clinical features: 55 patients (26 M, 29 F) in 30 families were identified. While 18 patients (32%) were referred with a diagnosis/suspicion of FA, in 26 (47%) FA was diagnosed at our institution. The most frequent anomaly was short stature (14 patients, 25%), skin changes (7, 12%), urogenital abnormalities (7, 12%), dysmorphism/craniofacial abnormalities (7, 12%), hands anomalies (4, 7%); 12 (22%) had no recorded anomalies. 18 patients (33%) developed a malignancy either before or after diagnosis of FA: solid tumors in 5 (9%), AML and/or MDS in 15 (27%); 3 (5%) of these patients had both solid tumors and AML/MDS. Diagnostic Tests: 35 patients (63.6%) had a positive CB analysis with diepoxybutane (DEB) or mitomycin-C (MMC) testing; in 5 patients (9%) DEB testing was borderline and 3 (5%) had a normal CBA but had a diagnostic phenotype+/- family history and presence of a homozygous mutation in a known FA related gene. 14 patients had cytogenetic abnormalities and abnormalities involving chromosome 1 were the most frequent (50%). Mutation Analysis: Mutational analysis was available for 12 (22%) cases; homozygous mutations in FA genes were identified in 10 patients (18%) in 7 families (23% of families): FANCA (5 patients/3 families); BRIP1 (2/2); FANCP (1/1); FANCD2 (2/1). In one case, post matched sibling (HSCT) blood sample revealed a known pathogenic heterozygous c.2632G>C,p.Glu878Gln mutation in FANCA, suggesting a carrier donor. Proteomic analysis: Over 1650 unique PBP protein species were identified of which 605 were significantly differentially expressed (≥ 2 to ∞ - fold change & p < 0.001) between SAA /FA/ normal control subjects (Fig 1a). DNMT3A, Kinase Insert Domain Receptor (KDR) and TGFB-1 was found to be highly expressed in SAA versus FA, while ATM and APOB were highly expressed in FA versus SAA (Fig.1b). Treatment outcomes: 36 out of 55 patients (65%) received HSCT. Actuarial survival of HSCT (n=37) and non-HSCT (n=14) patients was 70% and 77%, respectively. Treatment details were not available on 6 (11%). CONCLUSION: We report the first characterization of AYA patients with FA in Saudi Arabia. Our report emphasizes the need for a high index of suspicion of a diagnosis of FA in BMFs. CB may be falsely negative in cases, and panel based and/or WES based NGS testing increases diagnostic accuracy; in this cohort, mutations in FANCA were the most frequent (50%). Occurrence of hematological and solid tumors is a significant risk in these AYA patients. We also report proteomic panels as potential biomarkers that distinguish FA from SAA and may provide mechanistic insights. Disclosures No relevant conflicts of interest to declare.

Clinical and molecular diagnosis of most hematological malignancies including Chronic Myeloid Leukemia (CML) can be accurately made. However, prediction of treatment response and estimation of disease survival period eludes the currently available tools for patient care. Quantitative expression proteomics can potentially be developed as effective tool to monitor therapy response towards achieving personalized medicine for CML patients. We have over 10 years follow up period for some of the CML patients, and the majorities of them are alive and doing well on Imatinib. On the other hand, a small fraction of the patients were switched to alternative Tyrosine Kinase Inhibitors (TKI) and some underwent bone marrow transplants (BMT). Our follow up results stratified all 37 analyzed newly diagnosed CP-CML patients into 5 distinct cohorts including 52% on Imatinib, 12% on Nilotinib, 9% on Dasatinib, and 15% BMT, while 12% of the patients had disease-related mortality. Kaplan-Meier survival curve showed no significant difference between all patients on TKI and BMT that were alive under a follow up period of 4-11 years compared. On the other hand 3 of 4 patients had disease related deaths less than 2 years of diagnosis. Only one patient survived for almost 10 years (Figure 1). Besides survival analysis, peripheral blood samples obtained from the patients at time of diagnosis were subjected to expression proteome analysis using label-free quantitative liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). A subset of significantly differentially expressed proteins was able to distinctively discriminate samples into their respective treatment response and disease outcome groups based on unique protein expression signatures (P 2- ∞- fold change, (Figure 2). Some of the identified proteins were implicated in hematological diseases including CML as potential biomarkers using Ingenuity Pathway Analysis. These protein signatures once validated in larger sample cohorts might be capable of prediction of molecular response, choice of therapy and disease outcome for CML patients. Therefore; allowing for identification of would be high risk patients that might potentially benefit from aggressive treatment at point of diagnosis pre initiation of conventional therapy. Altogether our findings indicate that analysis of panel of protein markers have the potential of clinical utility for prediction of response to therapy, disease survival and objective prognostication of disease outcome, thus bringing personalized medicine closer to CML patients. Disclosures No relevant conflicts of interest to declare.

Introduction: Induction with 3+7 has been standard practice in acute myeloid leukemia (AML) for over 40 years. Addition of a 3rd agent or use of high dose Ara-C has been reported to show better CR rates, but this has not demonstrated a consistent improvement in overall survival. We have consistently used induction with idarubicin, cytarabine 100mg/m2 /day for 7 days and etoposide at 100mg/m2 in young patients, omitting etoposide for suspected secondary AML or AML with myelodysplasia related features, or in those in whom excess toxicity is suspected. Methods: All patients wholly treated for newly diagnosed AML were identified from the prospective institutional AML database. Patients were treated with either ICE (Idarubicin 12mg/m2 day 1-3, Ara-C 100mg/m2 day 1-7, Etoposide 100mg/m2 d1-3) or the same doses of idarubicin and Ara-C without etoposide (3+7). The latter was given in patients with dysplastic features or secondary AML or where there were concerns of toxicity. Results: We Identified 116 patients who received one of the 2 induction regimen between 2005 and 2013. 90 patients received ICE and 26 patients received 3+7. Median ages in the groups were 29y (14-56) and 37y (15-58), respectively. Cytogenetics by ELN classification were similarly distributed between the ICE and 3+7 groups, with favourable/intermediate/adverse cytogenetics comprising 22%/46%/26% and 23% / 38% / 26%, respectively. 21/90 (23%) in the ICE group had >5% blasts in a day 14 bone marrow vs 7/26 (27%) in the 3+7 cohort. There was no significant difference in the CR/CRi rate between ICE (82%) and 3 + 7 (77%) groups. The death in aplasia rate was similar at 3.3% and 3.8%, respectively. 65/90 (72%) and 14/26 (54%) of patients received a transplant in CR1 or beyond in the ICE and 3+7 groups, respectively. Leukemia free survival was 40% (SE 10%) and 40% (SE 5%) in both cohorts (Fig.1). Overall survival at 5 years for ICE and 3+7 were 57% (SE 6%) and 49 % (SE 13%), p=0.69 (Fig.2). Conclusion: Our experience in young adults, albeit retrospective, confirms findings of larger studies that demonstrate that addition of etoposide to induction does not appear to improve remission rates significantly or improve survival. In order to improve remission rates in younger adults, FLAG-Ida or other regimens consisting of high dose Ara-C and/or novel agents may provide more tangible improvements in remission rates, although strategies that translate these into better overall survival remain elusive and this should be the target of further prospective trials. Disclosures No relevant conflicts of interest to declare.

Introduction: Despite allogeneic hematopoietic stem cell transplantation (HSCT), prognosis of fms-like tyrosine kinase 3 (FLT3) mutated acute myeloid leukemia (AML) remains poor due to the high risk of relapse. Sorafenib, a multikinase inhibitor active on FLT3, has shown encouraging results in these patients. Patients and methods: Here, we report the use of sorafenib as a maintenance agent after HSCT in 28 adults with FLT3 positive AML treated in three hematologic departments. Results: A total of 18 males and 10 females were included. All but one patient (pt) underwent their first HSCT between 2012-2016. Median age at HSCT was 45 years (range 16-57). A normal karyotype was detected in all but 5 pts. Ten pts showed FLT3-ITD as sole molecular abnormality, thirteen with concomitant NPM-1 mutation, associated to WT1 overexpression in 1 case and to CEBP-α double mutated in two. Association of FLT3 and WT1 overexpression was observed in 3 pts. Two more pts presented a FLT3-TKD with concomitant NPM-1 mutation. At time of HSCT, all but 1 pt were in complete remission (CR; CR1, n=23; CR2=3; CR3=1). Thirteen pts in CR had a detectable minimal residual disease (MRD) before HSCT. Median interval from CR to HSCT was 74 days (d, range 6-220). The majority of the pts (n=26) received peripheral blood as stem cell source, 19 from a matched sibling, 4 from a matched unrelated, 3 from a haploidentical donor. A bone marrow unit was used in 2 pts, one matched sibling and one haploidentical donor. Conditioning regimen was myeloablative in 21 pts, while reduced intensity regimen was used in 5 pts, and 2 receiving a sequential regimen. All pts achieved neutrophil engraftment in a median of 16 d. Median time to sorafenib introduction as a maintenance agent after HSCT was 70 d (range 17-645). Seven pts were out of immunosuppressive treatment (IST) without graft-versus host disease (GVHD) at time of sorafenib start. Sorafenib was started at a dose of 400 mg twice a d (n=13), 200 mg twice a d (n=14) or 200 mg once a d (n=1). Sorafenib was used as primary prophylaxis in 25 pts, or as secondary prophylaxis in three relapsed pts who received it first in combination with salvage chemotherapy and then, after obtaining subsequent CR, as a maintenance treatment. Median duration of treatment was 179 d (range 4-1219). Dose reduction or withdrawal due to toxicities was needed in 5 and 3 pts, respectively. These included gastrointestinal (GI, n=3), cardiac (n=1), skin (n=3, 1 with GI), biochemical (n=1) and hematological toxicities (n=2, 1 with GI). Despite dose reduction, persistence of toxicities prompted to treatment withdrawal in 1 pt. Disease relapse occurred in 2 pts: in both sorafenib was withdrawn and then resumed after salvage chemotherapy. One pt died for disease progression, the other from non-relapse mortality. Twelve pts experienced GVHD (limited, n=6; extensive, n=6), resulting in dose reduction in 5 pts, followed by withdrawal in 1 pt. Nine pts required systemic IST. Dose reduction was made in 1 pt due to financial reasons. Three pts received donor lymphocyte infusion (DLI), without experiencing GVHD. Leukemia-free (LFS) and overall survival at one year were 91±6% and 89±7%, respectively. Probability of LFS with undetectable MRD at one year was 87±7%. With a median follow-up of 15 months (range 4-44), all but 2 pts are alive, all in CR. Sorafenib treatment is ongoing in 18 pts (with 7 at reduced doses) with a median of 15 months (range 1-41). Conclusion: Our findings suggest that a post-transplant prophylactic strategy is safe and may markedly improve the poor outcome of FLT3 positive AML. A large prospective randomized clinical trial is warranted in order to confirm our results and to determine the optimal treatment modalities. Although the optimal starting dose still remains unclear, dose individualization according to patient tolerability might be considered. Further analysis is needed to evaluate the immunomodulating role of sorafenib post HSCT. Figure 1 year Leukemia-free and overall survival Figure. 1 year Leukemia-free and overall survival Disclosures No relevant conflicts of interest to declare.

Introduction : Hemorrhagic cystitis (HC) is one of common complications after allogeneic hematopoietic SCT (HSCT) with reported incidence varying from 7 to 70%. Several reports have shown that BK is strongly associated with HC (BK-HC) following HSCT. We conducted an institutional retrospective study to analyze the incidence and clinical factors associated with BK-HC following HSCT. Methods : A total of 517 consecutive patients above the age of 14 years receiving HSCT from 2009 and June 2015 were included in this retrospective analysis and evaluated for HC and urinary BK. HC was defined as documented hematuria of any grade and BK viruria was defined as positive at any level by BKV quantitative PCR testing in urine. Patients were stratified, based on hematuria and urinary BK virus, into the following groups (a) BK virus positive hemorrhagic cystitis (BK+HC), (b) BK virus negative hemorrhagic cystitis (BK-HC) and (c) Non-hemorrhagic cystitis (HC-). Screening for microscopic hematuria was performed only for patients with any kind of urinary symptoms. Results: 479 patients (92.6%) were matched related donor and 308 (60%) were male with a median age of 24 (range 14 to 66). Diagnoses were AML for 195 (38%), ALL for 183 (35%) and bone marrow failure for 44 (8.5%). Conditioning regimen was cyclophosphamide based in 427 (82.6%) patients (97%) versus others in 90 (17.4%) patients. GVHD prophylaxis was CSA/MTX for 456 (88.4%) however, T cell depletion was used in 13%. Peripheral blood stem cells were used for 56% of patients. With a median follow-up of 60 months for survivors (range 2 to 116.5 months), 43 (8%) patients showed BK+HC, 264 (51%) BK- HC while 209 (41%) did not have any hematuria (HC- group). Median time from transplantation to BK+ HC was 67 days (range 7 to 1261 days). Univariate analysis for risk factors of BK+ HC showed male, use of T-cell depletion and AML diagnosis were statistically significant factors. Other factors like age, conditioning regimen, GVHD prophylaxis, stem cell source, mismatched and remission status were not statistically significant. BK+ HC group was associated with higher incidence of other infections like CMV viremia (p=0.01) and fungal infection (p Conclusion: Hematuria following allogeneic bone marrow transplantation occurs in almost half of patients (51%) while BK associated HC develops in 8% of patients. Factors associated with BK+ HC were male gender, use of T-cell depletion and AML diagnosis. BK+HC is usually associated with other infections like CMV viremia and fungal infections. Further studies are needed to minimize or prevent BK+ HC following HSCT especially in high risk group. Disclosures No relevant conflicts of interest to declare.

Introduction: The use of a Myeloablative (MA) regimen followed bypost-transplantation high dose Cyclophosphamide (PT-CY) has been adopted to overcome the increased relapse risk following nonmyeloablative conditioning regimen and unmanipulated Haploidentical Bone Marrow Transplantation, in patients with high-risk hematological malignancies, with acceptable TRM and risk of GVHD. We added ATG to our Myeloablative regimen with PT-CY after noticing significant incidence of grade II-IV aGVHD with the first few cases. Here we compare the outcomes of the 12 patients who received ATG to the outcomes of the first 11 patients who were transplanted without ATG. Patients and Methods: our haploidentical program was started in 2013 as a phase I/II prospective clinical trial. After reviewing the first 11 cases enrolled on the trial (MA regimen with PT-CY, without ATG), we noticed significant incidence of high grade aGVHD (54.55%). We amended our protocol in early 2015. Rabbit ATG was added at a dose of 3 mg/kg (1.5 mg/kg day -3 and day -2) to our conditioning regimen [thiotepa (5mg/kg/day on day -8 and -7), busulfan (3.2mg/kg/day IV day-6, -5 and -4), fludarabine (50mg/m2/day on day -6, -5 and -4 )] or [TBI 1000 cGy (200cGy twice a day on days -10, -9 and one dose on day -8), fludarabine (30mg/m2/day on Days -7, -6, -5 and -4)]. Graft-versus-host disease (GVHD) prophylaxis consisted of PT-CY (50mg/kg/day) on days +3 and +5, cyclosporine (starting day +4), and mycophenolate mofetil (starting day +1). Table 1 summarizes the disease-type and disease-status at transplant. Patient characteristics were comparable at baseline between the 2 groups. Results (Table 2): We enrolled patients with high risk hematologic malignancies in need for SCT but have no matched donor (MSD, MUD). Despite the small sample size, our results showed a statistically significant difference in the rate of acute GVHD between the 2 groups (p= 0.0161) in favor of the ATG group, chronic GVHD was more frequent in the non-ATG group however the difference did not reach statistical significance probably due to the small sample size. There was no statistically-significant difference in the risk of relapse, CMV reactivation or Hemorrhagic cystitis between the 2 groups. However, there was a trend of higher relapse rate (33.3% vs 18.18%), a higher rate of Hemorrhagic cystitis (50% vs 18.18%) and a higher rate of CMV reactivation (100% vs 81.82%) in the ATG group. The cumulative incidence of TRM at day 100 was in favor of the ATG group (figure 1), with a trend toward a better DFS in these patients 6 months post-transplant (figure 2). To be noted the follow up period was shorter for the ATG group because ATG was added later on. Figure 3 shows the survival for ATG vs non ATG group. Conclusion: The use of ATG with myeloablative Haplo conditioning can significantly reduce the risk of acute GVHD and early TRM. We have seen more relapses, higher rate of CMV reactivation, and hemorrhagic cystitis with the addition of ATG but these did not reach statistical significance probably due to the small sample size. A lower dose of ATG might be the way to go to strike a careful balance and improve the outcomes of myeloablative haploidentical transplant. Download : Download high-res image (36KB) Download : Download full-size image Download : Download high-res image (52KB) Download : Download full-size image Download : Download high-res image (219KB) Download : Download full-size image Disclosures No relevant conflicts of interest to declare.

Introduction: Various forms of aplastic anemia (AA)/bone marrow failure syndromes (IBMFs) show significant clinical and molecular heterogeneity with significant clinical overlap and are often diagnosed based on established clinical and pathological criteria. While >70 genes have been identified in patients with AA/IBMFs, most cases have are labelled as idiopathic with no identifiable genetic abnormlaity found. Precise detection of genetic abnormalities in these patients may assist in more accurate molecular diagnosis in these patients, proper counseling, cancer surveillance and personalized clinical intervention. Method: As part of the Saudi Human Genome Project, we developed a comprehensive 405 gene panel encompassing all known Mendelian hematological disorders (hemolytic anemias, aplastic anemias/bone marrow failure syndromes, coagulation disorders) using the Ion Torrent AmpliSeq technology. Patients who met the clinical diagnosis of aplastic anemia/bone marrow failure syndrome were enrolled into this study. Peripheral blood samples were subjected to this next-generation sequencing analysis. Results: We validated the Saudi Mendeliome assay using 642 samples with known mutations across various medical specialties. We then tested 37 patients with AA/IBMFS using this Proton-Ion sequencing platform. Mutations were identified in 7/37 (19%) of patients, followed by whole exome sequencing (WES) in those patients without identifiable mutations. Conclusion: Compared with clinical WES and/or whole genome sequencing (WGS), which are still expensive, time consuming and difficult to interpret, this novel and comprehensive targeted gene panel is more economical (< $150), faster (3-4 weeks), upgradable (by spiking in newly identified AA/IBMFs genes) and can be used to genotype patients with acquired aplastic anemia/bone marrow failure syndromes and guide their management. Second tier testing using WES/WGS is recommended for cases without identifiable mutations. Disclosures No relevant conflicts of interest to declare.

Introduction Predicting treatment outcome of acute leukemia has been an important issue. Many factors have been elucidated. We evaluated the impact of donor's availability on treatment outcome including mortality in patients with acute lymphoblastic leukemia (ALL). Methods A total of 294 patients with ALL were evaluated after receiving chemotherapy between year 2001 and July 2014 at our center. Patients were assessed for the need of hematopoietic stem cell transplants (HSCT), availability of HLA sibling match donor and the impact on overall outcome. Indications for transplantation were defined as (1) WBC->100,000 for T-ALL, >30 for B-ALL with, (2) cytogenetic abnormalities of t(9:22), (4:11) or (1:19), (3) relapse or primary refractory disease or (4) MRD positivity. Patients were divided into 3 categories, group A with an indication for HSCT and available donor (HSCT+/D+), group B with HSCT indication but no available donor (HSCT+/D-) and group C with no indication for HSCT regardless of donor status (HSCT-). Results The median age was 20 (14-63 years). 95 (32%) were female while 198 (68%) were male. 276 (86%) patients were newly diagnosed while 18 (14%) were relapsed. Immuno-phenotype was B for 191 (65%), T for 91 (31%) versus mixed lineage for 12 (4%). 33 (11%) patients were positive for Philadelphia chromosome. Median WBC at diagnosis was 23.2X109/L CNS involvement was positive in 26 (8%) patients. With a median follow-up of 60 months for survivors (range 2 to 116.5 months), 148 (50%) patients showed HSCT+/D+, HSCT+/D- in 79 (27%) and HSCT- in 67 (23%) patients. the 5-year OS for HSCT+/D-, HSCT+/D+ and HSCT- were 29%, 57% and 55% (p value Conclusion Our study suggested that unavailability of donor is an independent risk factor on OS. The use of alternative donor and building national /regional unrelated donor registry is highly warranted even in countries with high probability of finding matched sibling donor. Figure 1. Figure 1. Disclosures Kim: Bristol-Myers Squibb: Consultancy, Research Funding; Novartis Pharmaceuticals: Consultancy, Research Funding.

A Significant Proportion of Young Adult Patients with Post -HCT Relapse Of AML Benefit From Aggressive Salvage And 2nd Cellular Therapy. INTRODUCTION: There is currently no standard of care for patients with AML who relapse following hematopoietic cell transplantation (HCT), and outcomes in these patients are generally poor. Given this fact, there is great variability in practice, and many patients may be palliated in the absence of suitable clinical trials, especially following early relapses. We sought to analyse long-term survival of young adults with AML based on whether or not they received a second cellular therapy (CT) (second transplant or donor lymphocyte infusion [DLI]) following post-HCT relapse. METHODS: We retrospectively analysed data on patients who had received a HCT between 2000 and 2012 and had a post HCT relapse. The patients were stratified by whether or not they had 2nd CT with or without prior chemotherapy. Baseline characteristics and outcomes were compared. RESULTS: Ninety four patients were identified who had relapsed AML following HCT. The median age at transplant for the patients was 27.5 (range 14-58y) years for the whole cohort; 50% were females. Of these, 30 patients received 2nd CT either in the form of DLI (80% for available CT data) or a 2nd HCT. Median in age for both groups was 24 years and there was no significant difference between the 2 groups in good or poor risk cytogenetics. Median time to relapse was significantly lower in the group that did not receive 2nd CT vs the group that did (5.9 vs 18.2 months, p For the 64 patients that did not receive 2nd CT, reasons included early relapse (28 cases), presence of GVHD (15 cases), refractory to salvage (8 cases), poor performance (9 cases), and patient choice (4). The OS for patients who did not receive 2nd CT was 4.5 months ± 2.6% vs 36% ± 11% for patients who did receive 2nd CT (Fig.1). Of the 6 patients in the 2nd CT group who relapsed in Conclusion: The management of post BMT relapse remains challenging, and a number of factors may preclude intensive therapy post-HCT relapse. However, our experience confirms that a proportion of patients do benefit from long-term survival from a strategy of aggressive salvage followed either by DLI or a second HCT; in addition to disease biology, a treatment bias where early relapses are less likely to be treated aggressively partly explains the difference in outcome in the groups. This strategy should be considered in young fit patients and may lead to long-term survival in a significant proportion of young adults; patients with later relapses beyond 6 months appear to derive a greater benefit. Prospective clinical trials are required incorporating novel therapies in patients who relapse early post HCT. Disclosures No relevant conflicts of interest to declare.

Introduction: It is extremely significant to predict treatment outcomes using a biomarker. The prognostic significance of CD20 expression is controversial. In this study, we attempted to evaluate the impact of CD 20 expression on treatment outcomes in large cohort of adolescents and adults patients with acute lymphoblastic leukemia (ALL) treated with chemotherapy only in one single center. Methods: A total of 172 adolescent and adult patients with newly diagnosed B precursor ALL receiving CALGB based chemotherapy protocol between year 2001 and July 2014 at our Centre were evaluated for the expression of CD20 and it is impact on treatment outcomes. Anti-CD20 monoclonal antibody use were not part of the chemotherapy protocol at our Centre. Patients underwent hematopoietic stem cell transplantation were excluded from the analysis, a total of 83 patients were finally included in the analysis. CD20 expression at diagnosis of 20% in blast population was used as cutoff to stratify patients as CD20 positive (CD20+) versus CD20 negative (CD20-) group. Results: Median age for all patients is 21 years (range, 14-62), 41% (n=34) were females. Median WBC at diagnosis was 8 (range, 0.4-244), 28% (n=23) had WBC >30. Philadelphia (Ph) chromosome was negative for 75 patients (86%) while positive for 12 patients (14%). Day 28 blasts 5 (n=5) and missing for 4 patients (5%). A median follow-up of 3.7 years for survivors (range, 1-11) showed 29 patients (35%) had CD20+ versus 54 patients (65%) was CD20-. Comparison of patient's characteristics between the two groups were similar for gender, age, median WBC at diagnosis, median LDH, Ph chromosome, CNS involvement and primary refractoriness at day 28 of chemotherapy. The cumulative incidence of relapse at 1 year for CD20+ was 42% versus 15% (p=0.05) for + CD20- (Figure 1) while 5 years relapse rate was 55% versus 58%, respectively, suggesting higher incidence of 1 year relapse in CD20+ group. The overall survival for CD20+ was 39% versus 50% for CD20- (P=0.18). In Univariate analysis for One-year relapse, CD20 expression was significant factor (p=0.02, HR=2.97). Multivariate analysis confirmed CD20 as an independent adverse risk factor for relapse at 1 year (p=0.02, HR 2.97). For 5-years relapse, male gender (p=0.03, HR 2.1) and age >30 years (p=0.05, HR2.38) were found to be independent factors but not CD20 expression. Conclusion: The present study showed that the overall incidence of CD20 expression in B-ALL is 35%. Also, it suggested that in non-HSCT patients, CD20 expression at a diagnosis is associated with higher risk of early relapse at one year, which was confirmed by multivariate analysis. Further study is strongly warranted to confirm the prognostic role of CD20 and to evaluate the importance of anti-CD20 monoclonal antibodies in a prospectively designed study. Figure 1. Cumulative incidence of relapse at 1 year (A) and at 5 years (B) Figure 1. Cumulative incidence of relapse at 1 year (A) and at 5 years (B) Figure 2. Figure 2. Figure 3. Figure 3. Disclosures Kim: Bristol-Myers Squibb: Consultancy, Research Funding; Novartis Pharmaceuticals: Consultancy, Research Funding.

Introduction : Infertility is a major late effect of hematopoietic stem cell transplants (HSCT). In aplastic anemia (AA) patients, although the fertility recovery rate is relatively higher than other diseases but the exact incidence and risk factors are not very well studied. In this study, we attempted to evaluate incidence and the impact of patientÕs characteristics and transplantation procedures on fertility recovery following allogeneic HSCT for adolescent and adults patients with AA. Methods : A total of 157 patients who were at least 14 years old with AA receiving HSCT between year 1987 and 2014 at our center were reviewed. Patients who survived at least 2 years following HSCT and either married or in relationship were included in the analysis and evaluated for fertility following HSCT. 87 patients were eligible for the study. Questionnaire survey and long-term charts were used for data collection. With a response rate and or available information of 63% patients, 55 patients were identified and stratified into fertility recovery (FR+) versus non-fertility recovery (FR-) group. Fertility recovery was defined by a pregnancy of the patient or his partner. Results: Median age for all patients is 23 years (range, 14 -50), 44% (n=24) between 14-20 years old, 51% (n=28) between age 20-40 years and 5% (n=3) > 40 years. 51% (n=28) were females. Matched related donor was used for majority of patients 96% (n=53). GVHD prophylaxis was CSA/MTX for 93% (n=51,). Conditioning regimen was Cyclophosphamide/Flu in 25 (45%), Cyclophosphamide /ATG in 18 patients (35%) and others in 12 patients (20%). Bone marrow was the source of stem cells for 52 patients (94%). A median follow-up of 8 years for survivors (range, 0.3 -23) showed 45 patients (82%) had FR+ while 10 patients (18%) were FR-. Median duration of fertility recovery (from delivery to BMT) was 6 years (range, 0.8-19) with significant difference based on age groups, 4 years for patients 20-40 years (n=29, 53%) versus 8 years for those < 20 years (n=24, 44%), (p=0.002), (Figure 1). None of the patients >40 years old (n=2, 4%) had fertility recovery. Comparison based on gender showed no significant difference. Males had a median duration of fertility recovery of 5.9 years, (range 0.6-14.9) versus 6.2 years, (range, 0.8-15.2) (p=0.31) females. The overall median number of pregnancies was 2 (range, 1-6). For males, it was 2 (range, 1-6) while 1.5 (range, 1-5) for females (p=0.26). Deliveries occurred in natural ways in (95%) while C-section for (5%). All deliveries were without fetal abnormalities. Univariate analysis of risk factors for fertility recovery showed age group (p=0.03) and chronic GVHD (p=0.05) are important factors. Neither gender of patients or type of preparative regimens used for HSCT (Cyclo/ATG vs Cyclo/Flu) was a risk factor. In multivariate analysis, age group was the only confirmed an independent risk factor for fertility recovery (p=0.02) [HR= 2.02, CI=1.012-3.64). Conclusion: The present study suggested that the incidence of fertility recovery following HSCT for patients with aplastic anemia is high with no significant differences between males and females. Patients between the ages of 20-40 years at the time of HSCT have significantly shorter recovery period. Age was the only independent risk factor for fertility recovery while there was no impact of whether ATG or Fludarabine was used in addition to Cyclophosphamide as preparative regimen. Figure 1. Figure 1. Disclosures Kim: Bristol-Myers Squibb: Consultancy, Research Funding; Novartis Pharmaceuticals: Consultancy, Research Funding.

Purpose: Chronic Myeloid Leukemia (CML) among other hematological malignancies has witnessed development of advanced molecular diagnostics. However, there is an unmet need for efficient objective markers for selection of available therapeutic agents and accurate prediction of patient’s response. Clinical proteomics can potentially be complementary to currently existing proven tools to monitor therapy response towards achieving personalized medicine for CML patients. Experimental Design: Thirty four bone marrow and serum, samples from patients with newly diagnosed chronic–phase CML were subjected to expression proteome analysis using combined gel-based 2-DE and label-free in-solution quantitative liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The study aims to identify disease-specific/disease-associated protein biomarkers demanding less invasive procedures for objective prediction of individual’s best treatment options and prognostic monitoring of CML patients (Overview in figure 1). Results: Quantitative protein fingerprints from 2-DE analysis accurately predicts 13 individuals that achieved Major Molecular Response (MMR) at 6 months from 12 subjects without Major Molecular Response (NoMMR) using unsupervised principal component analysis (Figure 1 left lower panel). Some of the results were independently validated using label free quantitative liquid chromatography tandem mass spectrometry. Sixty three (63) differentially expressed proteins were identified (> 2- ∞- fold change, p < 0.05).The panel of proteins also discriminates accurately patients that stay on TKI after 1year of Imatinib Rx from patients ultimately requiring alternative treatment (Second Generation TKI/others). We have had more than 2 years follow up of these patients and the same dataset of potential protein biomarkers could still accurately separates all four sample groups into their respective molecular response and treatment sub groups (Figure 1 middle lower panel). Some of the identified proteins were implicated in hematological diseases as potential biomarkers using Ingenuity Pathway Analysis (Figure 1 right lower panel). Conclusion: Our results highlight the power of Proteomics as a molecular scanner for objective stratification of CML patients for treatment options. We have identified protein signatures capable of prediction of molecular response and choice of therapy for CML patients at 6 months and beyond. Our expression proteomics strategy is very promising for identification of clinically useful biomarkers. These proteins might be valuable once validated, to complement the currently existing parameters for reliable and objective prediction of disease progression, monitoring treatment response and clinical outcome of CML patients as a model of personalized medicine. Figure 1 Overview of our biomarker discovery proteomics approach. Bone marrow and peripheral blood samples were analyzed by 2-DE and LC/MS/MS. Identified proteins were subjected to multivariate statistical analysis and evaluated for early treatment response and prediction of individualized treatment options. Potential markers would be validated for clinical use. Figure 1. Overview of our biomarker discovery proteomics approach. Bone marrow and peripheral blood samples were analyzed by 2-DE and LC/MS/MS. Identified proteins were subjected to multivariate statistical analysis and evaluated for early treatment response and prediction of individualized treatment options. Potential markers would be validated for clinical use. Disclosures No relevant conflicts of interest to declare.

Purpose Despite advancements in diagnosis and treatment modalities for hematological malignancies, presently, there are no reliable blood tests for disease prognosis or prediction of patient’s response to particular treatments. Identification of such biomarkers for diagnostic or therapeutic response in clinical monitoring of hematologic diseases such as Chronic Myeloid Leukemia (CML) would be very useful. Experimental Design The ability to identify biomarkers in body fluids (i.e., plasma or serum) will not only involve minimally invasive procedures, but also more importantly, the potential for monitoring disease progression and effective response to therapy in relatively early stages. In this study, global proteome analysis of serum, plasma, and bone marrow samples from 28 patients with newly diagnosed chronic–phase CML were analyzed by using expression proteomics technology (label free quantitative liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The goal was to evaluate for early treatment response and discovery disease–specific /disease-associated proteins for prognostic monitoring and patient’s response to therapy at protein level. Results We identified a panel of 15 differentially expressed proteins (> 2- °- fold change, p< 0.001) to accurately discriminate between CML patients that achieved Major Molecular Response (MMR) vs. No-Major Molecular Response (NoMMR) at 6 months (Figure 1 & Table 1). Six (6) of the 15 identified proteins were filtered and mapped as potential biomarkers using Ingenuity Pathway Analysis. Among the identified proteins implicated in hematological diseases include Group-specific component (vitamin D binding protein), haptoglobin and vitronectin. Others were inter-alpha-trypsin inhibitor heavy chain 1, leucine-rich alpha-2-glycoprotein 1 and metallophosphoesterase 1. We also observed most of these proteins to be located in extracellular space, acts as transporters and have been implicated as markers of hematological disease and inflammatory response. Our data indicates that multivariate analysis of quantitative proteome data can potentially be useful as a means of unsupervised artificial intelligence algorithm for classification and stratification of clinical CML patients. Conclusion Our results highlight the power of proteomics in the discovery of biomarkers for more accurate prediction of prognosis and monitoring treatment response in CML patients. These proteins might be valuable, once validated, to complement the currently existing parameters for reliable and objective prediction of disease progression, monitoring treatment response and clinical outcome of CML patients. Disclosures: No relevant conflicts of interest to declare.

Abstract 1894 Background: Most of the studies of prognostic factors in acute myeloid leukemia (AML) are focused on predicting outcome after standard chemotherapy treatment. The studies that looked at the importance of these prognostic variables in predicting outcome after hematopoietic stem cell transplantation (HSCT) are very limited. Considering post-HSCT prognostic factors in stratifying AML patients may add a new level of confidence in any risk stratification of these patients. Toward this goal, we investigated the clinical relevance of CD34 expression in the primary leukemic cells on the outcome of allogeneic HSCT. Methods: Data collected from immunophenotyping of 110 patients with AML who were treated with HSCT was reviewed and the expression of CD34 on the blast population as determined by flow cytometry was correlated with clinical behavior and outcome. All the patients were treated with allogeneic HSCT. The median age of these patients was 24 (range: 14–57) and included 88 patients in the intermediate cytogenetic group and 22 in the adverse cytogenetic group. Of the 110 patients 71, (64.5%) were treated with HSCT in first remission (CR1). Results: Twenty-eight (25%) of all AML patients studied did not express CD34 on the surface of the blasts at diagnosis. Patients with CD34 negative blasts had significantly longer overall survival (OS) (P=0.003) as well as longer event free survival (EFS) (P=0.01) when all patients were considered. In the subgroup of patients who received HSCT in CR1, OS and EFS were significantly longer (P=0.017 and P=0.027, respectively) in the CD34-negative patients (N=20). Furthermore, if we consider only patients in the intermediate cytogenetic group at diagnosis, patients with CD34-negative blasts had significantly longer OS (P=0.007) and EFS (P=0.026). Even in patients with adverse cytogenetic abnormalities, OS and EFS were also significantly longer in the CD34-negative patients (P=0.01 for both). This was true when all patients were considered. The same was true when only patients transplanted in CR1 (P=0.05 for EFS in intermediate cytogenetics and P=0.05 for EFS in patients with adverse cytogenetic) were evaluated. Multivariate analysis including CD34 expression and FLT3 mutation status was carried out on a subset of patients (N=63) and showed CD34 expression was an independent prognostic factor for survival and EFS, while FLT3 mutation status became no longer a predictor. Conclusion: Our data suggests that CD34 expression on the blast cells at the time of AML diagnosis may have an adverse prognostic impact even after allogeneic HSCT. Lack of CD34 expression is a powerful independent favorable prognostic factor for AML patients if these patients are treated with HSCT after induction chemotherapy, irrespective if they were in CR1 or in CR2, and irrespective of their cytogenetic risk at diagnosis. Disclosures: No relevant conflicts of interest to declare.

Abstract 4894 Background: Pretreatment karyotypes of leukemic cells provide the core for risk-stratification schemes in acute myeloid leukemia (AML) and cytogenetic abnormalities are well established as the strongest prognostic factor for response to therapy and for survival in AML patients. Several cytogenetic risk classifications have been built to stratify AML patients. Only the recent European Leukemia Net (ELN) recommendations by an international panel proposed a new standardized cytogenetic reporting system for AML. More importantly, few studies attempted so far to validate the ELN requirements for risk assessment in AML patients treated with allogeneic hematopoietic stem cell transplantation (HSCT). We investigated whether our series of adult AML patients treated with HSCT could validate the ELN classification criteria. We also assessed the prognostic value of this new risk stratification scheme. Methods: ELN cytogenetic reporting criteria were applied to a series of 110 adult AML patients from a single institution in the Middle East for whom complete cytogenetic data from pretreatment leukemic marrow were available and patients were assigned to the proposed cytogenetic risk subgroups, accordingly. We compared outcome for the different prognostic subgroups. Parameters analyzed were overall survival (OS) and event-free survival (EFS). Our AML group included 62 (56%) patients treated in their first remission (CR1), while most non-CR1 AML patients were treated with HSCT in CR2. The median age of all patients was 25 years (range: 14–57). Results: The patient group included 32 (29%) patients with favorable risk, 60 (55%) in the intermediate-risk group, and 18 (16%) in the adverse-risk group. When all the three groups were considered, there was significant difference in overall survival (OS) (P=0.007) and event-free survival (EFS) (P=0.007). However, there was no significant difference between our favorable-risk group and the intermediate-risk group. This is most likely due to selection bias in the favorable group (e.g. CD56 expression and other unfavorable markers). The adverse-risk group had significantly (P=0.002) shorter survival with median survival of 7.5 months vs. the intermediate-risk group where median survival has not been reached with an average follow-up of 46 months. When we attempted to consider only patients treated with HSCT in the first remission, there were too few patients in the intermediate-risk group (7 patients) for statistical evaluation. Conclusions: The ELN criteria proofed valuable in risk-stratifying our set of adult AML patients who were treated with HSCT and represent a Middle Eastern population. Our series clearly validated the ELN classification. The ELN classification needs further validation in patients treated with HSCT in first remission. Disclosures: No relevant conflicts of interest to declare.

Abstract 4900 Background: Trisomy 8 is the most common chromosomal change in AML, as sole aberration in 5 % of cytogenetically abnormal cases and occurring together with other abnormalities in an additional 10% and little is known about the pathogenetic impact of trisomy 8. Most studies reported trisomy 8 in AML to be associated with intermediate risk. However, some reports have identified a poorer outcome than is usually seen in the intermediate group, considering trisomy 8 an adverse prognostic factor. More importantly, the clinical behavior and outcome of patients with trisomy 8 who are treated with hematopoietic stem cell transplantation (HSCT) is not known. We investigated the outcome in patients with trisomy 8 who were treated with HSCT. Methods: Bone marrow conventional cytogenetic and FISH data from 110 adult AML patients was reviewed and patients divided into three cytogenetic risk groups according to the European LeukemiaNet reporting system while separating patients with trisomy 8 into another, fourth, independent group. Patients with trisomy 8 as part of a complex karyotype (complex = 3 or more abnormalities) were excluded. We also compared outcome of patients with trisomy 8 to the intermediate-risk group alone and adverse-risk group alone, respectively. The AML cohort included 62 (56%) patients treated in their first remission (CR1) while most non-CR1 AML patients were treated with HSCT in CR2. The median age of all patients was 25 years (range: 14–58). Results: Patients with trisomy 8 were 9 (8%). Patients with trisomy 8 showed significantly longer overall survival (OS) (P=0.02) and event-free survival (EFS) (P=0.03) as compared to patients with adverse cytogenetics. The outcome of trisomy 8-positive patients was similar to the intermediate-risk group. Conclusions: This data suggests that trisomy 8 in AML is an intermediate-risk factor when patients are treated with HSCT. While we did not compare the outcome of HSCT with the outcome of trisomy 8-positive patients treated with intensive chemotherapy, most likely the cytogenetic risk of trisomy 8 for patients after HSCT is similar to their cytogenetic risk when treated with chemotherapy. Disclosures: No relevant conflicts of interest to declare.

Abstract 4627 The internal tandem duplication (ITD) and tyrosin kinase domain (TKD) D835 mutation in the Fms-like tyrosine kinase receptor-3 gene (FLT3) are perhaps the most studied prognostic molecular markers in acute myeloid leukemia (AML). However most of the studies have been in patients treated with standard intensive chemotherapy. The prognostic significance of FLT3, especially the TKD D835, in AML patients treated with intensive chemotherapy followed by allogeneic hematopoietic stem cell transplantation (HSCT) is not well studied.We studied the prognostic value of both FLT3-ITD and FLT3-D535 mutations in patients with AML treated with HSCT. Methods: Samples from 87 patients with AML were analyzed for FLT3 ITD and D835 mutations using fragment length analysis for ITD and restriction enzyme digestion followed by fragment length analysis for D835. All patients were diagnosed with AML, treated with intensive chemotherapy, then HSCT. They included 66 (76%) patients with intermediate cytogenetic abnormalities and 21 (24%) patients with adverse cytogenetics. Results: ITD mutation was detected in 18 patients (21%) patients, while the D835 mutation detected in 6 patients (7%). FLT3-ITD was associated with significantly shorter overall survival (OS) when all patients are considered (P=0.006). When only patients with intermediate cytogenetic abnormalities treated with HSCT in their first complete response (CR1) are considered, FLT3-ITD was significantly associated with poor OS (P=0.001). Event free survival (EFS) was also significantly shorter in patients with the FLT3-ITD (P=0.005). Similarly, D835 mutation was associated with significantly shorter OS (P=0.002) in this group of patients. Surprisingly, in patients with poor cytogenetic abnormalities, patients with FLT3-ITD had significantly longer survival (P=0.05), although the number is too small. Conclusion: Our data suggests that FLT3 mutations, both ITD and D835, remain poor prognostic markers in patients with AML treated with intensive chemotherapy followed by HSCT, but only in patients with intermediate risk cytogenetic abnormalities and this may not be relevant in patients with high-risk AML. Disclosures: No relevant conflicts of interest to declare.

Abstract 4880 Background: The CD56 is a neural cell adhesion molecule (N-CAM) expressed in natural killer cells. CD56 expression on the surface of leukemic cells in acute myeloid leukemia (AML) has been reported to correlate with higher rate of relapse and to be associated with poor outcome when patients are treated with conventional intensive chemotherapy. The role of allogeneic hematopoietic stem cell transplantation (HSCT) in improving outcome in this subgroup of AML patients is not known. We investigated whether the outcome of CD56-positive AML patients differ from average AML patients when treated with allogeneic HSCT after intensive chemotherapy and its prognostic relevance in patients transplanted in the first (CR1) or second complete remission (CR2). Methods: Immunophenotyping data of 106 patients with AML who were treated with allogeneic HSCT was reviewed. The expression of the CD56 on the blast population as determined by flow cytometry was correlated with clinical data and outcome. The median age of patients was 24 (range: 14–57) and included 72 patients in the intermediate cytogenetic group and 30 in the adverse cytogenetic group. Of the 106 patients, 71 (67%) were treated with HSCT in their first remission (CR1) and the remaining patients were treated in CR2. Results: Twenty nine (28%) of all studied patients expressed CD56 on the surface of the blasts at diagnosis. When we consider only patients treated with HSCT in CR1, 17 (24%) were CD56 positive. The overall survival (OS) and event free survival (EFS) for patients who were positive for CD56 were not significantly different from the rest of the patients in the CR1 group. In contrast, in the group of patients who were treated with HSCT after relapsing (CR2), patients with CD56 positivity had significantly shorter OS (P=0.03) and DFS (P=0.006). In this group, 11 of the 35 (31%) were CD56+ and their median survival was 8.85 months while the median has not been reached in the CD56 negative patients. Conclusion: Our data suggests that the expression of CD56 in AML is a significant poor prognostic factor if patients are treated with HSCT after relapsing in their second remission. Although this should be confirmed in larger studies, the CD56 expression in AML should be considered as an adverse risk factor and favors treatment with allogeneic HSCT in the first remission and not after relapse in second remission. AML patients with CD56 positive blasts have higher incidence of relapse after chemotherapy and they might lose their opportunity of good outcome if HSCT is delayed and performed only in the second remission. Disclosures: No relevant conflicts of interest to declare.

Abstract 4464 Background: Alterations of the short arm of chromosome 12, most often resulting in loss of chromosomal material, are a recurrent feature in myeloid malignancies and occur in about 5 % of cytogenetically abnormal AML. Chromosomal abnormalities of 12p in AML have been reported to be associated with a non-favorable outcome. However, it is unclear how dismal the outcome is, as AML with 12p abnormalities is variably included in the intermediate or poor prognosis groups. Moreover, the role of allogeneic hematopoietic stem cell transplantation (HSCT) on outcome of patients with 12p abnormalities is not known. We investigated whether HSCT can improve the poor survival of patients with 12p abnormalities. Method: Bone marrow conventional cytogenetic and FISH data from 110 adult AML patients was reviewed and patients were divided into three cytogenetic risk groups according to the European LeukemiaNet reporting system while separating the patients with 12p aberrations into one independent fourth group. We also compared outcome of the 12p group with to the intermediate group alone or after combining intermediate with favorable, since there was no significant difference between the favorable and the intermediate groups. The AML cohort included 62 (56%) patients treated in their first remission (CR1) while most non-CR1 AML patients were treated with HSCT in CR2. The median age of all patients was 25 years (range: 14–58). Result: Patients with 12p abnormalities were 4 (4%). Patients with 12p abnormalities had a significantly shorter overall survival (OS) (P=0.03) and event-free survival (EFS) (P=0.04). Their outcome was similar to the adverse-risk cytogenetic group, and survival was significantly shorter than in the intermediate group (P=0.02). The poor outcome was significant even when only patients treated with HSCT in first remission were considered. All four patients with 12p abnormalities were treated with HSCT in CR1. Conclusion: Although the number is small, this data suggests that 12p chromosomal changes in AML are significant adverse abnormalities, not different from complex cytogenetics, and treatment with HSCT does not change this dismal outcome. This also suggests that for patients with 12p abnormalities, alternative therapeutic approaches should be considered. Disclosures: No relevant conflicts of interest to declare.

Abstract 4643 Background: Mutations in the genes encoding for the cytosolic isocitrate dehydrogenase 1 (IDH1) and the mitochondrial version of this enzyme (IDH2) have been reported in acute myeloid leukemia (AML) and other types of cancer. Presence of these mutations in AML correlated with more aggressive disease in some studies, but other studies did not find significant correlation with outcome when patients were treated with intensive chemotherapy. The polymorphism at rs11554137 in IDH1 was reported to correlate with inferior outcome in cytogenetically normal AML patients. Most of the studies evaluating the prognostic relevance of IDH1, IDH2 and the rs11554137 polymorphism were reported in patients treated with standard chemotherapy. The prognostic significance of these markers is not fully studied when AML patients are treated with intensive chemotherapy followed by allogeneic hematopoietic stem cell transplantation (HSCT). We studied the prognostic value of the IDH1, IDH2, and rs11554137 polymorphism in patients with AML treated with HSCT in first complete remission (CR1). Methods: Samples from 69 patients with AML were analyzed for mutations in IDH1, IDH2, and the SNP rs11554137 by direct sequencing. All patients were diagnosed with AML, treated with chemotherapy followed by HSCT in CR1. They included intermediate (N=42) and adverse (N=27) cytogenetic risk groups. Results: The R132H and the SNP C to T change at rs11554137 (silent G105) in IDH1 were detected in 5 (7%) and 6 (9%) of 69 AML patients. The IDH2 mutations (N=5; 7%) included R140Q, 172K, and T169A. Patients with IDH1 or IDH2 mutations did not differ significantly in their overall survival, event free survival, or time to relapse from those without mutation. In addition, the rs11554137 SNP polymorphism did not correlate with outcome in this group of AML patients. We also looked at the combination of mutations as compared with cytogenetic risk and found no difference in survival or event free survival based on IDH1 or IDH2 mutations or rs11554137 polymorphism in the intermediate cytogenetic risk group. Conclusion: The data suggests that HSCT after intensive chemotherapy in CR1 may neutralize the negative prognostic impact of IDH1 and IDH2 or the rs11554137 SNP polymorphism. However, the number of cases is relatively small and further studies with larger number of cases are needed. Disclosures: No relevant conflicts of interest to declare.

Abstract 4091 Background: CD34 is a member of the trans-membrane sialomucin proteins expressed on the surface of hematopoietic cells and plays an important role as a cell-cell adhesion factor and mediates attachment of stem cells to extracellular matrix. Clinically, CD34 and other surface markers, such as CD13 and CD33, are frequently used as differentiation markers: CD34 for stem cells and CD13 and CD33 for myeloid differentiation. CD34 is not expressed on the surface of leukemic cells in a significant number of patients with acute lymphoblastic leukemia (ALL). CD13 and CD33 are expressed on the surface of lymphoblasts in few ALL patients. The clinical significance of CD13 and CD33 expression on the surface of lymphoblasts in ALL has been studied extensively in patients treated with conventional chemotherapy. The clinical relevance of the expression of CD34, CD13 and CD33 on outcome in ALL patients treated with allogeneic hematopoietic stem cell transplant (HSCT) is not known. We studied the prognostic relevance of the expression of CD34, CD13, and CD33 on outcome of adult ALL patients when treated with allogeneic HSCT, either in the first remission or after relapsing and correlated the expression with outcome. Methods: Data collected from immunophenotyping of 62 patients with ALL who were treated with HSCT was reviewed and the expression of the CD34, CD13, and CD33 on the blast population as determined using flow cytometry was correlated with clinical behavior and outcome. Thirty-eight (61%) of these patients were treated with HSCT in first remission (CR1), while the rest of the patients were transplanted in the second or third remission. The median age of these patients was 19 (range: 14–43) and included 17 females (27%) and 45 males (73%). Cytogenetics at diagnosis classified the patients as intermediate in 24 cases (39%), adverse in 31 (50%), and favorable in 5 (8%). Cytogenetic data was not available on two patients. Results: Twenty-four (39%) of all patients did not express CD34 on the surface of the blasts at diagnosis, while 13 (21%) patients expressed CD13 and 19 (31%) expressed CD33. ALL patients who did not express CD34 had significantly shorter overall survival (OS) (P=0.003) and event free survival (EFS) (P=0.009). However, when only patients who were treated with HSCT in CR2 or CR3 were considered, CD34 expression was not relevant for OS or for EFS. Patients treated with HSCT in CR1 had significantly better OS (P=0.00) and EFS (P=0.00) if they expressed CD34. In contrast, expression of CD13 or CD33 had no impact on OS or EFS. Conclusion: Our data suggests that CD34 expression, and not CD13 or CD33, has a favorable impact on overall survival as well as EFS in adult ALL patients being treated with HSCT in CR1, however it loses its prognostic relevance in patients transplanted in more advanced disease. Disclosures: No relevant conflicts of interest to declare.

Abstract 4586 Chronic lymphocytic leukemia (CLL) is considered more common in Western countries and its incidence is believed to decrease moving east across the globe. CLL is believed to be less common in the Middle East compared to Western countries, although reliable statistical data is not available. Therefore, monoclonal B-cell lymphocytosis (MBL), a pre-CLL condition, is expected to be less common in non-Western countries. In Western countries, MBL prevalence as detected by flow cytometry varies from 0.6% to 14% in healthy individuals older than 40 years, dependent on the level of sensitivity and number of parameters applied. Using 4 to 6 color flow cytometry, most studies report a prevalence of approximately 5 % in the Western population with the CLL-phenotype about 5 times more prevalent than the non-CLL phenotype. MBL incidence and relative proportions of CLL-phenotype versus non-CLL phenotype have not been adequately studied in non-Western countries. We investigated the prevalence and phenotype of MBL in a population sample in the Middle East. Method: 365 individuals, mostly Saudi Arabian nationals and a smaller number of individuals from neighboring countries, aged over 50 years with normal peripheral blood counts and no evidence of hematologic disease. Peripheral blood samples were immunophenotyped by 8-color flow cytometry detecting CD45, CD19, CD20, CD5, CD10, CD3, kappa and lambda light chains, based on acquiring approximately 1 million cells each. Result: Monoclonal B-cells were detected in 21 (6%) individuals (14 male, 7 female, median age 70, range 64–91). However, only 10 cases (48%) displayed the typical CD19+/CD5+ CLL-phenotype. Two cases (9.5%) were CD5-negative clonal B-cells, and 2 (9.5%) were CD10+ clonal B-cells. The remaining 7 cases (33%) showed concomitantly a CD5+ and a CD10+ clonal population, both expressing the same light chain. While we cannot be certain if these CD5+ and CD10+ cell populations represent the same or different clones, the finding that the two populations in all 7 cases showed the same light chain restriction supports the assumption that the two populations represent the same clone. Conclusion: MBL in the Middle Eastern region observed in this study is as common as reported in the Western world. In contrast to Western countries, however, it is the non-CLL phenotype which is more prevelant, comprising 52% of our MBL group and most of these cases show cells expressing CD5 and cells expressing CD10. The exact classification of these cases is difficult. It seems likely that these cases represent marginal zone phenotype, but the possibility of a coexisting follicular lymphoma clone cannot be excluded. Pure follicular lymphoma phenotype is seen in 10% of our MBL cases. Further studies with long follow-up are needed. Disclosures: No relevant conflicts of interest to declare.

Abstract 1465 The gene for the transcription factor CCAAT/enhancer binding protein α (CEBPA) is important for the differentiation of granulocytes and has been reported to be mutated in patients with acute myeloid leukemia (AML). Double mutation of CEBPA has been shown to be associated with good outcome in the cytogenetic intermediate-risk subgroup. Multiple single nucleotide polymorphisms (SNPs) have been reported in this gene in addition to a 6-nucleotide insertion. Most of the studies of prognostic relevance of CEBPA have been reported in patients treated with standard chemotherapy focusing on the mutations in the CEBPA gene. The prognostic significance of CEBPA is not fully studied in AML patients treated with intensive chemotherapy followed by allogeneic hematopoietic stem cell transplantation (HSCT) in their first complete remission (CR1). We studied the prognostic value of the CEBPA mutations and the SNPs in patients with AML treated with HSCT in CR1. Methods: Samples from 69 patients with AML were analyzed for CEBPA mutations by direct sequencing of the entire coding sequence of the gene. All patients were diagnosed with AML, treated with intensive chemotherapy, then received HSCT in CR1. The group included intermediate (N=42) and adverse (N=27) cytogenetic risk groups. Results: Double CEBPA mutations were detected in 7 patients (10%). However, silent G to T (690g>t) transition in rs34529039 SNP (silent T230) was detected in 15 patients (22%). The same genotype was detected in 17% of normal control individuals. The prevalence of rs34529039 T genotype in our patient population was similar to that detected in the United State population (Quest Diagnostics data: 17% in normal controls and 28% in AML patients). Outcome in patients with double mutations did not differ significantly in event free survival (EFS) or overall survival (OS) in this group of patients, although the number of patients with double mutation is too small. In contrast, the T rs34529039 genotype was significantly associated with shorter EFS (P=0.03) and time-to-relapse (P=0.006). The same trend is seen for OS, although the P-value is not significant due to very few events. When we excluded patients with adverse cytogenetic abnormalities, similar results were obtained and EFS was significantly poor in patients with T phenotype (P=0.04 for EFS). Conclusion: The data suggests that HSCT after intensive chemotherapy in CR1 may neutralize the prognostic value of CEBPA double mutations. However, the rs34529039 is a very important independent adverse prognostic factor in patients with AML and should be used in stratifying patients. Disclosures: No relevant conflicts of interest to declare.