Litzow, Mark R.

Background: High-dose chemotherapy and hematopoietic stem cell (HSC) transplantation is considered standard therapy in patients with chemosensitive relapsed diffuse large B cell lymphoma (DLBCL). BCNU, etoposide, cytarabine and melphalan (BEAM) is a standard widely used DLBCL conditioning regimen. Chemotherapy doses, both standard and high dose, are traditionally based in body surface area (BSA) and are often calculated using the corrected ideal body weight. However, this practice is empirical and the best way to dose chemotherapy is unknown. Weight-based dosing has been suggested to better predict toxicity of the conditioning regimen. We correlate the BEAM dose/actual weight ratio with toxicity and overall outcome in a uniform cohort of patients receiving HSC transplant for relapsed DLBCL Methods: Retrospective analysis of 80 consecutive patients treated at Mayo Clinic, Rochester, MN between 2001 and 2006 who received a HSC transplant following BEAM conditioning was performed. All doses were based on BSA calculated using the corrected ideal body weight. Weight-based dose intensity was retrospectively calculated utilizing the melphalan dose/Kg as a surrogate for the entire regimen. Weight-based dose intensity was correlated with toxicity in the first 30 days after transplant and survival outcome. Results: Median age at the time of transplant was 62 (interquartile range 53–65; range 26–77); 65% were males; median number of prior chemotherapy regimens was 2. Median dose of melphalan was 3.2 mg/Kg (interquartile range 2.9–3.6; range 2.2–4.5). Only one patient died within 30 days of the transplant. Patients who received > 3.6 mg/Kg of melphalan were more likely to have Grade 3 or 4 mucositis (44.4% v. 9.8%, P=0.001) than the remaining patients. Median numbers of days spent in the hospital in the first 30 days after transplant was 13 (3–18) for melphalan dose >3.6 mg/kg vs. 7 (0.5–10.5) for the remaining patients (P=0.043). Weight based dose intensity did not correlate with survival (P=0.8) or disease-free survival (P=0.3). Conclusion: Weight based dose intensity of BEAM correlates with toxicity post autologous HSC transplant. Patients receiving doses corresponding to >3.6 mg/kg of melphalan are at increased risk of high-grade mucositis and prolonged hospitalization. Figure Figure

Abstract Background: POEMS syndrome is a devastating syndrome, characterized by peripheral neuropathy, organomegaly, endocrinopathy, monoclonal plasma cells, skin changes, papilledema, volume overload, sclerotic bone lesions, thrombocytosis, & high VEGF. We noted an unexpectedly high transplant related morbidity, which we have since postulated to be ES. Methods: 30 patients with POEMS were treated with PBSCT at Mayo Clinic Rochester. We retrospectively studied outcomes, with an emphasis on treatment related morbidity. Two definitions of ES were used: Spitzer (BMT 2001) and Maiolino (BMT 2003). Results: Two-thirds were male. Median age was 48, range 20–70. Time from first symptoms and diagnosis was 26 and 4 months, respectively. To mobilize stem cells, CTX/G-CSF was used in 5 & G-CSF in the remainder. Conditioning was Mel200 (n=19), Mel140 (n=10), and BEAM (n=1). Post-transplant 15 had GM-CSF begun day+6. Only 10% remained outpatient, and median time to discharge from hospital was transplant day 17 (range 0–175). Factors predicting for later dismissal included age (p=0.04), abnormal CXR 7 to 17 days post transplant (p<0.0001), & bolus corticosteroids (CS) beyond day 12 post-transplant (p=0.006). Ninety-three percent had fever, although only 9 had bacteremia. Eight satisfied criteria for ES according to Spitzer and 14 according to Maiolino. Another 3 patients received steroid bolus days 8, 12, and 11 for presumed ES but did not meet criteria because of delayed ANC recovery (days 16, 18, and 20, respectively). Of the 5 patients requiring endotracheal intubation, 3 satisfied Maiolino’s criteria for ES. Although these 3 received bolus CS during their course, administration was delayed at 18, 14, and 18 days. The patient whose CS bolus antedated intubation only received prednisone 30 mg/day. In toto, fourteen patients received bolus CS (daily doses between 20 and 1200 mg prednisone equivalents) commencing day 8 to 59. Those 7 patients who received CS before day 13 did better than the 7 who received them day 13 or later (Table). Conclusions: It is essential to recognize that nearly 50% of patients satisfied formal criteria for ES as defined by Maiolino. In these patients ES may run a self-limited course or lead to catastrophe. No Steroid (n=16) Steroid ≤ D12 (n=7) Steroid > D12 (n=7) P *Engraftment syndrome according to definition of Maiolino (M) or of Spitzer (S). ES M / S, n* 5 / 2 4 / 4 5 / 2 NA Wt change, % 0.6 (−.4.2–6.7) 6.7 (3.6–27.2) 11.2 (–2.1–23.2) 0.005 Rash, % 27 71 43 0.13 Diarrhea, % 73 86 86 0.71 Tmax, C 39 (37.8–41) 40.1 (39–41.1) 38.9 (38.7–40.8) 0.08 1st fever, day 10 (6–15) 8 (7–9) 12 (8–146) 0.007 Abn CXR1, % 13 71 71 0.03 Ventilator, % 0 14 71 0.004 First WBC, day 12 (8–21) 14 (12–14) 14 (12–17) 0.03 ANC500, day 15 (12–29) 16 (14–115) 18 (15–45) 0.08 PLT20, day 12 (8–41) 20 (11–115) 24 (9–170) 0.05 PLT50, day 15 (11–192) 32 (16–115) 56 (13–551) 0.03 RBCs, units 3 (2–8) 6 (4–31) 11 (6–64) 0.0008 PLTS, aph. units 2 (1–9) 9 (4–51) 18 (4–60) 0.0004 Hosp dsm, day 15 (13–36) 21 (15–69) 41 (16–175) 0.009

Abstract Abstract 2568 Background: Obesity is associated with an increased risk of development of adult AML (Relative Risk approx. 2-fold) (Ross J, Cancer Epidemiol Biomarkers Prev 2004;13:1810) and significantly higher mortality in pediatric AML (Lange B, JAMA 2005;293:203). We therefore examined the association of obesity with presenting characteristics in 2 recent large ECOG phase III adult AML trials to determine whether there was a unique clinical and genetic phenotype, and also the impact of obesity on clinical outcomes (complete remission - CR; early death - ED; overall survival - OS) in association with other known risk factors. The impact of obesity on receiving full-dose daunorubicin (D) was also evaluated in these studies. We included patients (pts) from E1900 receiving standard infusional cytarabine with intensified D (45 vs. 90mg/m2) in adults age ≤60 yrs (NEJM 2009;361:1249), and from E3999 receiving conventional intensive chemotherapy +/− the MDR-inhibitor zosuquidar in adults age >60 yrs (Blood 2010;116:4077). Obesity was defined as Body Mass Index (BMI) >30kg/m2. Methods: Pt baseline characteristics were compared using Fisher's exact (categories variables) or Wilcoxon rank sum tests (continuous variables). Logistic regression models were used to examine the association between obesity and CR or ED; Cox models stratified on induction treatment arms were used to examine the association between obesity and OS. Multivariate models to examine the effect of Obesity controlled for known prognostic factors (including cytogenetics & secondary AML - sAML). Results: A total of 1089 pts (E1900, n=651; E3999, n=438) with available BMI data were included, the median follow-up of living pts is 4.7 yrs. Obesity was prevalent, with n=359 (33%) of pts with a BMI>30 at presentation. For all patients, median BMI was 27.1 (range 16.7–93.0); for non-obese patients median BMI was 25.0 (range 16.7–29.96) while for obese patients the median BMI was 34.0 (range 30.0–93.0). Obese pts were older (p=0.06), and significantly more likely female gender (p=0.05), ECOG PS>0 (p=0.01), & Intermediate Risk cytogenetics (p=0.006) but not sAML (14% overall, p=ns). Genotyping for FLT3 & MLL was performed in E1900 pts (age ≤60yrs): there was no difference in incidence of FLT3-ITD, but lower incidence of MLL-PTD was observed (p=0.08) in obese pts (not performed in E3999) (See Table). Overall, only 3.7% of pts received <90% of intended D dose. However obesity was significantly associated with receiving <90% intended D dose: in E1900, 11% of obese pts received <90% intended D (45mg/m2 cohort, p<0.001; 90mg/m2 cohort p=0.002), while in E3999 4% obese pts received <90% intended D (45mg/m2, p=0.07). There was no clear difference in toxicity/adverse events during initial induction therapy reported in obese vs. non-obese pts. On multivariate analysis obesity was not significantly associated with achieving CR (p=0.09), and had no direct independent association with ED (p=0.38). Kaplan-Meier plots of OS are shown in Figure. On multivariate analysis, age (p<0.001); ECOG PS (p<0.001); cytogenetic risk group (p<0.001); sAML (p=0.03); gender (p=0.05); and peripheral blasts (p=0.003) but not obesity were significantly associated with OS. Receiving <90% intended D dose was marginally associated with increased hazard ratio for OS (HR 1.50, 95%CI 0.98–2.28, p=0.06). Conclusion: Obesity is associated with specific presenting clinical characteristics in adult AML (female, older, PS>0, Int. risk cytogenetics, less frequent MLL-PTD), but has no direct impact on CR, ED or OS in the setting of a controlled therapeutic trial. Obese pts are at risk of receiving <90% intended D dose, which may impact OS. This analysis suggests that factors that predispose to adult AML may present with a unique clinical phenotype. Disclosures: No relevant conflicts of interest to declare.

Abstract Background Voriconazole is a common antifungal medication used in allogeneic hematopoietic stem cell transplantation (allo-HSCT) patients. In solid organ transplantation, multiple studies have associated the use of voriconazole with the development of squamous cell carcinoma (SCC) post-transplant, but its association with SCC in allo-HSCT patients is unknown. We sought to determine this association. Methods After IRB approval, Mayo Clinic’s transplant database (2007-2012) was accessed and electronic charts of allo-HSCT patients were retrospectively reviewed. Voriconazole exposure was defined as exposure to voriconazole at any time during treatment of primary disease, prior to or following HSCT. Cumulative voriconazole exposure was defined as total days of voriconazole use following HSCT; days were not required to be consecutive. Two time-dependent voriconazole exposure variables were defined: (1) history of voriconazole exposure (yes/no) over time, and (2) cumulative days on voriconazole over time. Results 404 patients underwent allo-HSCT during this timeframe, and 381 patients (table 1) were included in the final analysis. 23 patients were excluded (8 patients received multiple transplants, 9 patients were treated under pediatric protocols, 6 patients lacked research consent). 312/381 received voriconazole; other antifungal therapy included fluconazole (n=40), posaconazole (n=23), anidulafungin (n=1), and caspofungin (n=5). Median duration of cumulative days of voriconazole was 214 (range 2 -1553). SCC developed in 26/312 exposed to voriconazole and in 1/69 who received alternative antifungals. Cumulative incidence of SCC at 1 year was 3%, 2 years was 8%, 3 years was 13%, 4 years was 14%, and at 5 years was 19% (figure 1). Cumulative days of voriconazole use was found to be a risk factor for the development of SCC, and this relationship persisted in a multivariate model using previously identified risk factors (gender, age at transplant, TBI conditioning regimen, skin cancer pre-HSCT, chronic GVHD) as covariates (HR 1.859 for each 180 days of use, p<0.001). History of prior voriconazole exposure was not associated with an increased risk of SCC after covariate adjustment (HR 2.436, p=0.2369). Conclusion This is the first study to establish cumulative days of voriconazole use as a risk factor for SCC development following allo-HSCT, and may help guide appropriate antifungal prophylaxis in this patient population which is already at an increased risk of developing skin cancers. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 680 Cytogenetics play an essential role in determining the prognosis of patients with AML. However, there is still no validated cytogenetics grouping scheme that specifically applies to patients undergoing allogeneic stem cell transplantation, which hampers accurate prognostication and risk stratification. We studied 821 adult patients (median age 41, range 18–74) who underwent SCT between 1999 and 2004 for AML (excluding APL) in CR1 or CR2 and who were reported to the CIBMTR from centers with >20 patients meeting study criteria. 75% of patients received a myeloablative conditioning. 496 patients had a normal karyotype. The primary cytogenetics reports were manually reviewed for 92% of the patients with an abnormal karyotype. We compared the ability of the 6 existing grouping schemes (MRC, CALGB, EORTC/GIMEMA, SWOG/ECOG, DFCI, and Monosomal Karyotype (MK) classifications) to stratify patients, using both the Akaike Information Criterion in multivariable models and the C-statistic. Among all existing schemes, the DFCI system provided a marginally superior stratification for overall and leukemia-free survival. We also built a new classification using individual cytogenetic abnormalities in a Cox model that included other significant covariates (performance status, therapy-related disease, conditioning intensity, graft source, donor match, duration of CR1, and gender match). This CIBMTR scheme (see Table), which is similar to the DFCI scheme except for the inclusion of patients with t(8;21) in the intermediate group, could stratify patients into 3 groups with similar treatment-related mortality but significantly different overall survival, leukemia-free survival, and incidence of relapse. This scheme appeared to apply to both patients in CR1 and in CR2 (see FiguresF2). This transplant-specific scheme could be adopted for prognostication purposes and to stratify patients with karyotypic abnormalities entering transplantation clinical trials. Future studies may clarify the relative outcome of patients with t(8;21) and refine this scheme with the inclusion of molecular abnormalities. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 852 Adult acute lymphoblastic leukemia (ALL) is an aggressive disease with <30% long-term survival. This relatively poor outcome can be explained in part by an increased frequency of high-risk molecular subtypes compared to childhood ALL, such as BCR/ABL (20%-40% in adults vs 2%-5% in children). We hypothesized that aberrant epigenetic gene regulation contributes to the pathogenesis and clinical features of adult ALL. We therefore performed genome-wide DNA methylation and gene expression microarray studies of 215 adult patients with B-lineage ALL enrolled in the ECOG E2993 phase III trial. Patients had a median follow-up 4.75 years (3.5 months to 13 years) and median age 39 years (17 to 63 years). BCR/ABL(+) cases (n=83) had a worse overall survival (OS, p=0.08) than BCR/ABL(-) cases (n=132). The smaller difference in survival in this series between BCR/ABL(+) and (-) cases is likely due to the use of imatinib in some of these patients. The HELP microarray assay was used to measure DNA methylation at 50,000 CpGs annotated to ∼22,000 RefSeq promoters. The accuracy of HELP was confirmed by extensive quantitative single locus validation studies. Supervised analysis revealed the presence of a markedly aberrant DNA methylation signature (166 genes) in BCR/ABL(+) ALL with the cutoff values of p<0.001 (FDR<0.002) and log fold change>1, and a differential gene expression profile of 416 genes at p<0.001 (FDR<0.004) and log fold change>1. Integrative analysis of expression and DNA methylation indicated that many of these genes are functionally connected within a gene network centered around IL8, which was over expressed and hypomethylated in BCR/ABL(+) cases, along with IL2RA(CD25), CEBPB, ABL1, ID1, IL15, BCL2L13, CD69, NOV, S100A8 and S100A9. KEGG and BioCarta pathway analysis also showed enrichment for IL8 signaling, NF-kB Activation, B Cell Development and Antigen Presentation pathways, suggesting these cytokine networks might play central and distinct roles in BCR/ABL(+) ALL. To identify a core set of functionally relevant genes, we explored the overlap of the DNA methylation and gene expression signatures. The overlap consisted of 13 genes, among which 11 showed inverse correlation, including CD200, GAB1, HLA-DQA1, HLA-DQB1, IL2RA (CD25), LST1, LTB, NOV, ROB04, S100A9, and CD38. Consistent with previous ECOG findings, CD25 positivity was a more dominant predictor than BCR/ABL, and could further stratify BCR/ABL(+) patients into a favorable (CD25-) and a poor (CD25+) outcome group (OS, p=0.07). When comparing CD25(+) and CD25(-) groups among BCR/ABL(+) cases, we found RhoH and UBE2J1 as the top differentially methylated and IL2RA(CD25) as the top differentially expressed genes, and all three genes showed concordant corresponding changes in expression and methylation. The aberrant DNA methylation signature of MLL/AF4 cases was even more dramatic, with 469 identified as differentially methylated (p<0.001 (FDR<0.015), log fold change>1) and 1108 genes differentially expressed (p<0.001 (FDR<0.009), log fold change>1). Integrated analysis of DNA methylation and expression implicated gene pathways centered around TNFA and MYC, respectively. A core set of 44 genes were identified overlapping between the methylation and gene expression signatures, among which 34 showed inverse correlation, including ANXA5, BRE, CAPG, CEBPA, FAIM, FLT3, FUT4, IGFBP7, IL1R2, ITGA7, ITGAE, MAP1A, MAP7, MRPL33, PARP8, RBKS, SLITRK4 and TFR2 with overexpression and hypomethylation, and BTBD3, CCR6, FYN, GAB1, GYPC, HPS4, IL2RA, KCNK3, LCK, LST1, LTB, PRKCH, QPCT, S100A13, SGPL1 and ZAP70 with underexpression and hypermethylation in MLL/AF4(+) ALL. All signatures were independent of B-ALL differentiation stage. Using univariate Cox Hazard Regression model adjusted by age, WBC, CD25 and BCR/ABL status, we furthermore identified 259 expression and 115 methylation markers which were significantly correlated with patient OS risk (p<0.01). Molecularly or immunophenotypically defined poor prognosis adult B- ALLs thus feature specific aberrant DNA methylation profiles with associated inversely correlated gene expression. These gene sets delineate specific biological functions that may contribute to disease phenotype and offer an opportunity for development of targeted therapy. Aberrantly methylated genes in adult B-ALL correlate with clinical risk independent of other clinical or molecular risk factors. Disclosures: No relevant conflicts of interest to declare.

Abstract Introduction: The therapy of relapsed/refractory AML remains poor and new treatment options are sorely needed. The Leukemia Committee of ECOG devised a randomized phase II trial of 3 novel regimens to determine overall response rates could be improved. Methods: Patients between the ages of 18 and 70 years with a prior diagnosis of AML who relapsed <1 year after initial achievement of complete remission (CR) or who were refractory to initial induction therapy (<2 courses) or to first reinduction after a relapse (<1 course) were eligible for this trial. Eligible patients were randomized equally to one of three regimens described in Table 1 below. The primary endpoint was achievement of a morphologic complete remission (CR) or a CR with incomplete blood count recovery (CRi). A 2 stage statistical design was planned with 18 patients (assuming 16 eligible) to be accrued in the first stage. If at least 3 CR+CRi were seen among the 16 eligible patients, an additional 19 patients (assuming 17 eligible) would be entered in the second stage. If 8 or more CR+CRi were seen in the 33 eligible patients, this would be considered evidence of a promising response rate. Results: This study activated October 16, 2008 and closed August 2, 2013 with a total of 92 patients accrued (91 eligible). The eligibility criteria were amended during the study to lower the upper age limit from 70 to 65 years because 6 treatment related deaths occurred in the initial 27 patients accrued to the FLAM regimen. All of these patients died of septic shock or multi-organ failure and 5 of the 6 died within 1 month of the start of therapy. Most of these patients were over age 65 ( 53, 62, 67, 68, 69 and 69 years). At the first stage analysis, of the first 16 eligible patients accrued to each arm there were 2 CR and 2 CRi in the CT arm, 2 CR and 2 CRi in the FLAM arm and 2 CR in the sirolimus-MEC arm. Thus, the sirolimus-MEC arm was closed to accrual with a total of 20 eligible patients and second stage accrual continued for the CT and FLAM arms. Among the 35, 36 and 20 eligible patients accrued to arms A, B and C, respectively, there were 2 CR and 3 CRi in the CT arm, 6 CR and 4 CRi in the FLAM arm, and 2 CR and 1 CRi in the sirolimus-MEC arm. All 10 CR or CRi of the FLAM arm were among the first 33 eligible patients, therefore FLAM was the only regimen to achieve our target. The overall response rates for arms A, B and C were 14% (90% CI 7.1% - 34.7%), 28% (90% CI 16.1% - 43.0%) and 15% (90% CI 4.2% - 34.4%), respectively. Among the 92 patients accrued, there were 5, 10 and 2 grade 5 events within 30 days of the end of therapy in arms A, B and C, respectively. The vast majority of these deaths were attributed to infection and multi-organ failure except two which were secondary to disease. Conclusion: In this high risk group of AML patients the FLAM regimen showed an encouraging response rate. A randomized phase II trial has also recently been completed exploring its use in the front-line setting with newly diagnosed high-risk AML. While the FLAM regimen was excessively toxic in elderly patients with relapsed or refractory disease, it is a suitable option for younger patients in this setting. Arm A: CT Carboplatin 150 mg/m2/day over 24 hours by continuous infusion IV for 5 days (days 1-5) Topotecan 1.6 mg/m2/day over 24 hours by continuous infusion IV for 5 days (days 1-5) Arm B: FLAM Flavopiridol 30 mg/m2 for ½ hour followed by 60 mg/m2 over 4 hours IV per day for 3 days Cytarabine 667 mg/m2 over 24 hours by continuous infusion IV for 3 days (days 6-8) Mitoxantrone 40 mg/m2 IV over 1-2 hours (day 9) Arm C: Sirolimus-MEC Sirolimus 12 mg by mouth on day 1, followed by 4 mg by mouth daily for 8 days (days 2-9) Mitoxantrone 8 mg/m2/day over 15 minutes IV for 5 days (days 4-8) Etoposide 100 mg/m2/day over 1 hour IV for 5 days (days 4-8) Cytarabine 1000 mg/m2/day over 3 hours IV for 5 days (days 4-8) Table 2. Responses Table 1. Chemotherapy Regimens Regimen n Median age (range), years Responses (%) Deaths (first 30 days) (%) CT 35 55 (23-67) 5 (14%) 5 (14%) FLAM 36 62 (19-69) 10 (28%) 10 (28%) Sirolimus-MEC 20 52 (22-68) 3 (15%) 2 (10%) Disclosures Off Label Use: Sirolimus-potentiate chemotherapy Carboplatin-chemotherapy for AML treatment Topotecan-chemotherapy for AML treatment.

Abstract Abstract 897 Recent changes in allogeneic hematopoietic cell transplantation (HCT) including increased use of reduced-intensity conditioning, peripheral blood cells as the graft source (PB) and unrelated donors (URD) warrant re-evaluation of risk factors for acute graft-versus-host disease (aGVHD) and its impact on overall survival (OS). Risk factors for these outcomes were analyzed using more recent data from CIBMTR observational database. Methods: The cohort included adult patients ≥ 20 y transplanted from an HLA-identical sibling (SD) (n=3191) or URD (N=2370) for acute myelogenous leukemia (AML), acute lymphoid leukemia (ALL), chronic myeloid leukemia (CML), or myelodsyplastic syndrome (MDS) using a T-cell replete graft from 1999–2005. Six groups were created to evaluate the impact of conditioning [(myeloablative (MA) and reduced-intensity or non-myeloablative (RIC)], total-body irradiation (TBI) and graft source [(bone marrow (BM) or PB] as follows: MA+TBI+PB (group 1), MA+TBI+BM (group 2) MA+ no TBI+PB (group 3), MA+ no-TBI+BM (group 4), RIC+PB (group 5) and RIC+BM (group 6). Separate analyses were performed for SD and URD. IBMTR grade was used to classify aGVHD. A p-value of ≤ 0.01 was considered significant. Results: Among the SD cohort, the probability of aGVHD grade B-D and grade C-D at 100 days was 39% (95% CI, 37–41%) and 16% (95% CI, 14–17%). In multivariate analyses, non-TBI based MA regimens with a BM graft (group 4), RIC conditioning with PB (group 5) and tacrolimus plus methotrexate aGVHD prophylaxis were associated with lower odds ratio of grade B-D aGVHD (Table 1). The probability of OS was 51% (95% CI: 49–53%) at 3 y and 46% (95% CI: 44–49%) at 5 y. In multivariate analyses, grade B-D aGVHD was associated with a higher risk of death. Other independent risk factors for OS are shown in Table 2. Among the URD cohort, the probability of aGVHD grade B-D and C-D at 100 days was 59% (95%, CI 57–61%) and 32% (30-34%). In multivariate analysis, BM with MA (TBI and no TBI) or RIC conditioning (groups 2, 4 and 6) were significantly associated with lower odds ratio of grade B-D aGVHD (Table 1). Other independent risk factors included a diagnosis of CML. HCT from a 7/8 HLA-mismatched URD showed a trend for higher incidence of aGVHD (p=0.02). The probability of OS was 38% (95% CI: 35–40%) at 3 y and 33% (95% CI: 31–35%) at 5 y. In multivariate analysis, grade B-D aGVHD was associated with a higher mortality. Table 2 shows other independent risk factors for OS. Conclusion: Intensity of the conditioning regimen, TBI and the graft source has a combined effect on the risk of aGVHD. In both SD and URD cohorts, BM with MA, non-TBI regimens were associated with lower risk of aGVHD. In URD cohort, BM after a RIC also was associated with a reduced risk of aGVHD. Modulation of these risk factors is needed to reduce acute GVHD incidence and death after allogeneic transplantation. Disclosures: No relevant conflicts of interest to declare.

Abstract Background: Relapse after ATRA-based induction therapy is relatively uncommon in patients with acute promyelocytic leukemia (APL). Long term follow up studies have estimated a 15-25% relapse rate. Autologous and allogeneic hematopoietic stem cell transplantation (HCT) has been used as an effective salvage strategy. We present a single institution study of the outcomes of patients with relapsed APL that underwent HCT. Methods: After due IRB approval, the Mayo Clinic Transplant Database was retrospectively reviewed to identify all patients across three Mayo Clinic sites with relapsed APL that underwent HCT from 1995-2013. Data was abstracted at diagnosis and at relapse. The aims of this study were to report the descriptive characteristics of patients, with a focus on HCT outcomes. Results: Baseline Patient Characteristics A total of 15 patients (9 (60%) males) with relapsed APL that underwent HCT were identified. Median age was 36 years (range: 19-63) and median follow up from diagnosis was 8.8 years (range: 1.7-17). 2 (13%) deaths (1 from relapse) were recorded. 14 (93%) received ATRA and anthracycline-based induction therapy and 1 received anthracycline-based induction without ATRA. All relapsed patients achieved a complete remission (CR) after induction. Median time to relapse was 1.6 years (range: 0.6-3.9). 10 (67%) patients had a medullary relapse (hematologic-7(70%), cytogenetic -2 (20%) and molecular-1(10%)), 3 (20%) had additional extramedullary (EM) disease (CNS-2, myeloid sarcoma-1), while 2 (13%) presented with EM disease only (CNS-2). Salvage regimens included ATRA in 5 (33%) patients and arsenic trioxide (ATO) in 8 (53%) patients. 12 (80%) patients were transplanted in CR2 and 1 in CR3 (7%), while 2 (13%) had persistent disease (PD) at time of HCT. Allogeneic HCT 4 (27%) patients with a median age of 37 years (range: 33-49) underwent allogeneic HCT. 2 (50%) patients received myeloablative (MA) conditioning and 2 received reduced-intensity conditioning (RIC). 2 patients who underwent MA HCT had PD at time of transplant, while 1 patient in CR3 received a RIC. 2 (50%) patients developed acute GVHD while 2 (50%) had extensive stage chronic GVHD. At a median follow up of 2.6 years (range: 0.3-10.9), 3 (75%) patients remain alive and disease-free. 1 patient died of infectious complications within 100 days of transplant. Autologous Transplantation 11 (73%) patients with a median age of 40 years (range: 23-68) underwent autologous HCT with MA conditioning. 7 (64%) patients were in molecular remission at time of HCT, 3 (27%) patients transplanted before 2004 were in cytogenetic remission and information about type of remission was unavailable in 1 patient. At a median follow up of 6.8 years (range: 0.5-16) since HCT, 1 (9%) patient had a documented relapse at 175 days after HCT and died of disease-related complications. 10 (91%) are alive and in remission. Conclusions: Our single-institution study reaffirms the efficacy of HCT for APL patients with medullary and EM relapse. Autologous HCT has excellent long-term results in selected patients in CR2. Allogeneic HCT was mainly reserved for patients with high risk disease (CR3) and persistent disease at time of HCT. Table 1: Baseline Patient Characteristics N (%) Number of patients 15 Follow up (years) (median, range) 8.8 (1.7-17) Age at diagnosis (years) (median, range) 36 (19-53) Gender Male 9 (60%) Female 6 (40%) Sanz risk score High 4 (29%) Intermediate 8 (57%) Low 2 (14%) Induction Regimen ATRA + anthracycline 14 (93%) Anthracycline-based 1 (7%) Response to induction therapy CR 15 (100%) Time from diagnosis to relapse (years) (median, range) 1.6 (0.6 - 3.9) Type of relapse Hematologic 7 (47%) Cytogenetic 2 (13%) Molecular 1 (7%) Hematologic and EM 3 (20%) CNS only 2 (13%) Salvage regimen ATRA-based 5 (33%) ATO-based 8 (53%) Chemotherapy only 2 (13%) Table 2: Outcomes at HCT N (%) Age at HCT (years) (median, range) 38 (23-68) Disease status at HCT CR2 12 (80%) CR3 1 (7%) PD 2 (13%) Type of HCT Allogeneic 4 (27%) Autologous 11 (73%) Conditioning regimen Myeloablative 13 (87%) Non-myeloablative 2 (13%) Follow up since HCT (years) (median, range) 4.5 (0.3 - 16.3) Disease status at last follow up CR 13 (86%) Relapsed disease 1 (7%) Unable to assess 1 (7%) Alive at last follow up 13 (87%) Disclosures No relevant conflicts of interest to declare.

Abstract Abstract 851 Clinical studies have demonstrated that acute myeloid leukemia (AML) is heterogeneous with respect to presentation and to clinical outcome, and many studies have shown that cytogenetics can be used to improve prognostication. More recently, it has been shown that FLT3, NPM1, and CEBPA mutations can be used to further risk stratify AML patients. Although recent studies have identified novel, recurrent somatic mutations in AML in genes including TET2, ASXL1, IDH1, IDH2, and PHF6, their prognostic value has not yet been evaluated among patients treated on a large phase III clinical trial. Here we report full-length DNA resequencing of FLT3, NPM1, CEBPA, H/K/NRAS, KIT, WT1, TET2, ASXL1, IDH1/2, TP53, RUNX1, PTEN, and PHF6 in pre-treatment genomic DNA from 398 patients with de novo AML younger than 60 years of age enrolled in the ECOG E1900 protocol. We could identify a clonal alteration, defined as a somatic mutation or cytogenetic abnormality, in 91.2% of all patients; 42% had 1 somatic alteration, 36.4% had 2 alterations, 11.3% had 3 alterations and 1.5% had 4 or more somatic alterations. Mutational Analysis: We identified somatic mutations in FLT3 (37% total; 30% ITD, 7% TKD), NPM1 (14%), CEBPA (10%), TET2 (10%), NRAS (10%), WT1 (10%), KIT (9%), IDH2 (8%), IDH1 (6%), RUNX1 (6%), ASXL1 (4%), PHF6 (3%), KRAS (2.5%), TP53 (2%), and PTEN (1.5%) (Figure 1A). We then performed correlation analysis to determine the frequency of different mutational combinations in AML patients. In addition to previously identified mutational correlations (FLT3 and NPM1, KIT and core binding factor leukemia), we found that FLT3 and ASXL1 mutations were mutually exclusive in this large cohort (p =0.0008). In addition, we found that IDH1/IDH2 mutations were mutually exclusive of both TET2 (p=0.02), and WT1 (p=0.01) mutations consistent with overlapping roles in AML pathogenesis (Figure 1B). Integration of mutational data with response data and outcome: Mutations in ASXL1 (CR rate 33.3% versus 66.5% for ASXL1-WT patients; p= 0.009) were enriched in patients who did not respond to induction chemotherapy. We found that mutations in FLT3 (p=0.0005), ASXL1 (p=0.005; Figure 1C), and PHF6 (p=0.02) were associated with reduced OS. Notably, the adverse effects of ASXL1 and PHF6 mutations on outcome were restricted to patients treated with standard dose daunorubicin (p<0.01 for each mutational cohort); ASXL1 and PHF6 mutational status did not affect outcome in patients treated with high-dose daunorubicin, demonstrating that increased intensity induction chemotherapy can improve outcomes in genetically defined poor risk AML subsets. We also found that mutations in CEBPA (p= 0.04) and in IDH2 (p=0.003) were associated with improved OS; the favorable impact of IDH2 mutations on outcome was exclusive to patients with IDH2 R140Q mutations (Figure 1D). Within the subset of patients with cytogenetically defined intermediate risk AML, we found, as expected, that FLT3-ITD mutations were associated with reduced OS and CEBPA mutations were associated with improved OS. Importantly, we found that IDH2 R140Q mutations were associated with improved OS (p=0.003) in patients with intermediate risk AML regardless of FLT3 mutational status. In contrast, TET2 mutations (P=0.0002) and PHF6 (p<0.0001) were associated with reduced OS in intermediate risk, FLT3-WT, AML. Summary: These data provide important clinical implications of genetic alterations in AML and provides insight into the multistep pathogenesis of adult AML. We identified novel mutations that impact response to induction chemotherapy and predict overall outcome, including ASXL1, PHF6, TET2 and IDH2, suggesting these mutations can be used to improve AML risk stratification and therapeutic decisions in AML patients 18–60 years of age. Most importantly, we identify TET2, IDH1/2, and WT1 mutations as mutually exclusive somatic alterations that form a novel mutational complementation group that contributes to AML pathogenesis. Figure 1. A) Circos diagram depicting relative frequency and pairwise co-occurrence of mutations in de novo AML patients enrolled in the ECOG protocol E1900. B) Circos diagram showing mutational events in IDH1/2, TET2, and WT1 mutant AML patient. C) Overall survival in AML patients with and without ASXL1 mutations (p=0.005). D) Overall survival in AML patients with and without IDH2 R172 and R140 mutations (p=0.003). Figure 1. A) Circos diagram depicting relative frequency and pairwise co-occurrence of mutations in de novo AML patients enrolled in the ECOG protocol E1900. B) Circos diagram showing mutational events in IDH1/2, TET2, and WT1 mutant AML patient. C) Overall survival in AML patients with and without ASXL1 mutations (p=0.005). D) Overall survival in AML patients with and without IDH2 R172 and R140 mutations (p=0.003). Disclosures: No relevant conflicts of interest to declare.