Citations

Abstract Background: Acute graft versus host disease (aGVHD) is the leading cause of morbidity and mortality following allogenic hematopoietic cell transplantation (HCT). Corticosteroids are the first line treatment although <50% of patients with severe aGVHD (grades III-IV) achieve durable remissions. Monoclonal antibodies (mAb) are often used as second line agents for steroid refractory aGVHD (SR-aGVHD) (Patriarca et. al.; 2004). However, data regarding their tolerability and efficacy is retrospective and limited. We carried out this study to assess the clinical outcomes related to mAb therapy (Infliximab and Tocilizumab) for SR-aGVHD. Methods: Patients with SR-aGVHD that received therapy with either Infliximab or Tocilizumab between January 2003 and May 2016 were retrospectively identified. Clinical grading of aGVHD was per the Glucksberg criteria (Glucksberg et. al.; 1974). SR-aGVHD was defined as any grade progression within 3 days or failure to achieve at least one grade improvement within 7 days of initiation of systemic steroids. Infliximab and Tocilizumab were administered intravenously at 10mg/kg and 8mg/kg weekly for a total of 4 doses, respectively. Clinical response was evaluated at 4 weeks and 12 weeks post mAb treatment. Complete response (CR) was defined as sustained resolution of all clinical signs of aGVHD; partial response (PR) was defined as overall improvement of 1 or more grades; no response (NR) was defined as neither improvement nor worsening of the overall aGVHD grade. Overall response (OR) was defined as either CR or PR. Overall survival (OS) was calculated from the first day of mAb treatment until death or last available follow up. Results: Forty-three patients (median age 54, range 29-74 years; male 67%) with severe SR- aGVHD were included in the study. Of these, 35 (81%) received Infliximab for a median of 4 (range 1-6) cycles and 8 (19%) received Tocilizumab for a median of 3 (range 1-4) cycles. Both groups were comparable with regards to age, gender, conditioning regimen, graft source, degree of HLA match, ABO blood group, CMV incompatibility, and GVHD prophylaxis regimens. Only differences seen were a higher proportion of unrelated donor (p = 0.004) and cord blood HCT (p = 0.031) in the Tocilizumab group. Twenty (57%) of 35 patients treated with Infliximab and 6 (75%) of 8 patients treated with Tocilizumab had an overall aGVHD grade of IV prior to initiation of mAb therapy (p = 0.44). Organ specific distribution and severity of aGVHD are described in table 1. At 4 weeks post mAb therapy, 17 (40%) patients had an OR, 7 (16%) had no response, and 19 (44%) had died. Twenty-six (60%) patients died at 12 weeks, with OR and no response observed in 9 (21%) and 8 (19%) patients, respectively (table 2). Overall response for Tocilizumab versus Infliximab was comparable at 4 weeks (38% vs. 40%; p = 1.0) and at 12 weeks (38% vs. 17%; p = 0.33). Outcomes per aGVHD grade and gastrointestinal-specific stage at 4 weeks and 12 weeks are shown in figures 1-A and 1-B, with organ specific responses shown in figures 1-C and 1-D, respectively. The estimated median OS was 41 (range 4-3837) days for patients treated with Infliximab and 60 (range 10-756) days for those treated with Tocilizumab (p = 0.48). Disease relapse occurred in 5 (11%) patients treated with Infliximab and in none (0%) treated with Tocilizumab (p = 0.56). Thirty-four (79%) patients had infectious complications during and up to one month after mAb therapy. These included 31 (72%) patients with bacterial blood stream infection and 10 (23%) with invasive fungal infections. Overall, infectious complications were comparable (Infliximab - 83% vs. Tocilizumab - 63%; p = 0.33). CMV reactivation occurred in 11 (31%) and in 2 (25%) patients who were treated with Infliximab and Tocilizumab, respectively (p = 1.0). Given the retrospective nature of the study and the concomitant presence of aGVHD, it was difficult to attribute and grade gastrointestinal and hepatobiliary side effects. Conclusions: The use of anti-inflammatory monoclonal antibody therapy in patients with steroid refractory acute GVHD is associated with significant infectious complications (~80%) and poor response rates (~20% at 12 weeks). Current data, limited by a small sample size, does not show any advantages of using Tocilizumab over Infliximab or vice versa. Prospective clinical trials addressing this question are needed. Disclosures No relevant conflicts of interest to declare.

Abstract Background:The 2008 World Health Organization (WHO) developed a new classification system for Myelodysplastic Syndrome (MDS). The well-defined categories are refractory anaemia with excess blasts (type 1 or 2 based on the marrow blast count being below or above 10%), refractory anaemia with or without ringed sideroblasts, refractory cytopenias with multilineage dysplasia and myelodysplastic syndromes with isolated deleted 5q. MDS cases that do not meet the diagnostic criteria of the above categories are classified myelodysplastic syndrome (MDS-U). However, few reports in the literature exist in terms of natural progression and clinical outcome of patients with MDS-U. Aim: To study the clinical outcome of patients with MDS-U. Method: A retrospective, IRB-approved, single-institution study through chart review of cases with MDS at Mayo Clinic Rochester between 1993 and 2014 was performed. Patients diagnosed with MDS based on WHO classification were included. MDS classification was based on routine Mayo Clinic pathology reports. Central independent hematopathology review for bone marrow biopsy was performed for cases diagnosed with MDS-U or simply generic MDS. Comparison between groups’ medians was done using Wilcoxon test, while survival estimates were calculated using Kaplan-Meier curves using JMP V10. Result: A total of 802 patients, who met WHO criteria for MDS, were studied. Median age was 71 years (range, 18-99), 69% were males. Median white blood cell (WBC) 3.6 x109, hemoglobin (Hbg) 9.6 g/dl, platelets (PLT) 105 x109, peripheral blood (PB) blasts 0% and bone marrow (BM) blasts 2%. Median overall survival (OS) was 28 months. One hundred nine (14%) cases transformed to AML. Out of the 802 patients, 90 (11%) patients were initially classified as MDS-U according to 2008 WHO criteria, 69% were males with median age 71 years. Upon pathology review, only 42/90 cases (47%) were confirmed to be MDS-U (group 1). Among 47 cases not meeting MDS-U, 40% were best classified as RARS, 17% refractory anemia, and 9% as 5Q del Syndrome, while 2 cases did not have any myeloid neoplasm. Group 1 had median WBC 3 x109, Hbg 9.9g/dL, PLT 71 x109, PB blasts 0% and BM blasts 0%. IPSS grouping was low, intermediate-1, intermediate-2 and high in 27%, 52%, 21% and 0%, respectively. R-IPSS grouping was very low, low, intermediate, high and very high in 15%, 42%, 15%, 21% and 6%, respectively. Median OS in group 1 was 68, 37, 13 and 0 months per IPSS (p=0.04), and 101, 44, 14, 11, 13 months per IPSS-R (p=0.005), respectively. Of the 43 patients with MDS-U, 39 had follow-up; 21 patients (54%) of which progressed. MDS-U became 42% RAEB, 24% RCMD, 14% CMML, 5% RARS, 10% MDS/MPN, and 5% atypical. Group 2 (MDS other than MDS-U) 759 patients had median age 71 years, 69% were males. They had WBC 3.6 x109, Hbg 9.6g/dL, PLT 107 x109(p=0.01), PB blasts 0% and BM blasts 0%. IPSS grouping was low, intermediate-1, intermediate-2 and high in 29%, 44%, 22% and 5% respectively. R-IPSS grouping was very low, low, intermediate, high and very high in 17%, 32%, 20%, 17% and 14% respectively. On comparison between Group 1 vs 2, mOS was 27 vs 29 months (p=0.7), and percentage transformed to AML 14% in both groups. On multivariate analysis for mOS only age, IPSS-R and IPSS but not MDS-U nor gender were statistically significant. Conclusion: MDS-Uis a small subset of MDS. With independent pathology review, half of the MDS-U cases were subclassified into other MDS groups. In follow-up more than half of the cases were subclassified into other MDS groups and some were non-MDS. IPSS and IPSS-R are helpful tools for survival assessment in MDS-U. High risk MDS was infrequent in MDS-U per IPSS. We found no significant difference in mOS nor AML transformation when comparing MDS-U to other groups. Disclosures No relevant conflicts of interest to declare.

Abstract Introduction: Hypocellular myelodysplastic syndrome (h-MDS) represents only a small portion of MDS, of which, the clinical significance and outcomes are not well understood. Both laboratory and clinical evidence suggests that h-MDS shares immune-mediated pathogenic mechanisms similar to acquired aplastic anemia. As a result, immunosuppressive therapy (IST) has been the mainstay treatment. Since h-MDS is poorly understood and reported response rates to IST vary, we retrospectively reviewed the outcome of our patients with hypocellular MDS and identified the effectiveness of alternative therapy using hypomethylating agents (HMA). Methods: AllMDS patients over a 13-year period (June 1997 to May 2010) were captured after an IRB approval was obtained. Patients' demographics, labs, bone marrow aspirates and biopsies as well as cytogenetic data were collected. We used the currently accepted age-adjusted criteria to define hypocellularity as ≤ 30% in patients <70 years old, and ≤20% in >70 years old. Only patients with available response data were included in the final analysis. Survival estimates were calculated using Kaplan-Meier curves. Results: We identified 65 (8%) h-MDS patients from a cohort of 827 adult MDS. Median age was 68 years (range, 20-90), with 69% males. The largest group of patients were RAEB-1 at 9 (14%) and RAEB-2 at 14 (22%) along with RCMD at 18 (28%) and 15 (23%) MDS-U, 2 (3%) MDS 5q, 4 (6%) RARS and 2 (3%) were considered atypical. Cytogenetic analysis was normal in 17 (26%) with 7 (11%) having trisomy 8, and 11 (16%) and 14 (22%) having abnormalities of chromosome 7 and 5, respectively. IPSS-R were very low, low, intermediate, high, and very high in 4%, 30%, 28%, 21% and 17%, respectively. Leukemic transformation (LT) occurred in 6 (9%). The 4 year overall survival and progression free survival was 35% and 34%, respectively. Median overall survival and progression free survival was 30.2 and 29.7 months, respectively. Nine out 65 h-MDS patients were treated with a HMA, azacitidine (4) or decitabine (5). The median age of patients was 71 years (range, 66-85) with 6 (66%) being males. The median cellularity of the diagnostic bone marrow was 15% with the majority of patients presenting with RAEB-1 (11%) and RAEB-2 (55%) classification and 2 (22%) cases of RCMD as well as 1 (11%) case of MDS with isolated 5q. Cytogenetic analysis was normal in 3 (33%). IPSS-R were low in 1 (11%), intermediate in 4 (44%), high in 1 (11%) and very high risk in 3 (33%). The median time to initiation of a HMA from diagnosis was 5 months with response assessed at a median of 4.2 months. Two patients had received prior therapy including lenalidomide (for MDS 5q) and one had 1 cycle of trial therapy. Two patients (22%) achieved a marrow complete remission at a median time of 2.95 months; with one case of relapse at 9.8 months using HMA. Three patients (33%) had LT at a median time of 7.9 months post initiation of HMA. Median overall survival of patients with LT was 20 days. A total of 4 (44%) patients remain alive with a leukemia free survival of 67% at 2 years. In comparing to h-MDS patients without HMA treatment versus HMA treated, median OS was 28.2 vs 50.9 months (p=0.41) and PFS was 28.1 vs 40.6 months (p=0.69), respectively. Conclusions: The results from our clinical experience confirm that hypocellular MDS is a rare variant and that it is distinct from normocellular/hypercellular MDS. Two thirds of h-MDS received HMA for the treatment of higher risk disease (RAEB1-2). HMA has some efficacy in h-MDS. Further studies are warranted to better understand the clinical significance and outcomes of hypocellular MDS. Disclosures Binder: American Society of Hematology: Research Funding. Al-Kali:Celgene: Research Funding.

Abstract Background: Adult T-cell acute lymphoblastic leukemia / lymphoma (T-ALL) is a rare and aggressive hematological malignancy. Unlike B-cell ALL, apart from age and presenting WBC, additional prognostic factors remain largely unknown. Additionally, the prognostic impact of a monosomal karyotype, which has a negative impact on survival in myeloid neoplasms, remains to be determined in T-ALL (Kenderian et al, BCJ 2013) Aim: To study predictors of survival including the role of a monosomal karyotype in T-ALL. Methods: After due IRB approval, adults diagnosed with T-ALL from 1990-2014 at Mayo Clinic Rochester were identified. All clinical and pathologic data including FISH studies and cytogenetics were retrospectively reviewed. Chi-square test was used to compare variables. Survival was estimated and compared using the Kaplan-Meier Method and log-rank test. Univariate and multivariate analysis was performed using the Cox regression model. Results: Between 1990 and 2014, a total of 92 consecutive patients (pts) with T-ALL were identified, 41 had acute lymphoblastic lymphoma (LBL), and 51 (55%) acute lymphoblastic leukemia (ALL). Median age at diagnosis was 33 years (range; 18-88 years) with 72%males. Median follow up of our cohort was 25 months (range; 0.9-260 months) during which time 42 deaths (45%) were documented. A. Baseline characteristics: Fifty six (67%) had constitutional symptoms, and 63 (77%) had lymphadenopathy at diagnosis. Mediastinal mass was identified in 49 (55%) pts with palpable splenomegaly in 16 (20%) pts. Fifty one (58%) pts had extranodal disease, and 17 (19%) pts had CNS involvement. Pleural and pericardial effusion were evident in 16 (19%), and 6 (7%) pts, respectively. Median laboratory values included; LDH 288 U/L (115-6590), hemoglobin (Hb) 12.8 g/dl (4.5-18.2), WBC 8.65 x109 (1.4-406), platelets 169 x109 (8-485), bone marrow blasts 29% (0-99). B. Treatments: Induction therapies were variable and included; 11 (12%) CHOP like regimens, 7 (8%) modified NHL regimens (Asparginase+CHOP), 54 (58%) ALL like regimens (CALGB 9111, E2993, or HyperCVAD), 13 (14%) Pediatric regimens (ALL 10403, CCG 1961, BFM, Augmented BFM, GRAALL 2003, or Hoelzer regimen), with 7 (8%) patients' receiving palliative care only. Seventy-one (77%) pts achieved complete remission (CR1) during induction therapy while eight pts had refractory disease (8%). Thirty-three (35%) pts underwent stem cell transplant; 7 (21%) autologous and 26 (79%) allogeneic. Forty one (44%) pts had disease relapse and median time to relapse was 10.8 months (range; 8.2-16 months) C. Predictors of survival: In univariate analysis, that included age > 60 years, leukocyte count Hb, Plt, Blast percentage, mediastinal mass, LDH and CNS involvement, only age >60 and CNS involvement were predictors of inferior survival and both retained significance in the multivariable analysis with HR 3.9 (CI 1.5 - 9; p=0.0055) and 2.8 (1.3 - 5.7; p =0.0085), respectively (Figure 1 and 2). In this cohort age >60 was a better stratification that the conventionally used age above 40 (p = 0.1). Among 56 pts with evaluable cytogenetics data, 7 (13%) pts had MK which did not have an impact on survival with HR 1.9 (CI 0.4-5.6; p=0.33). Conclusion: In this large cohort of adult T-ALL patients, we observed that age >60 years and CNS involvement were independent predictors of inferior survival. MK was infrequent, but unlike in myeloid neoplasms, does not seem to impact overall survival. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Al-Kali: Celgene: Research Funding. Thompson:Kite Pharma: Research Funding. Witzig:Novartis: Research Funding; Celgene: Research Funding; Amgen: Honoraria; Spectrum: Research Funding; Valeant Pharma: Equity Ownership.

Abstract Background: Acute T-cell lymphoblastic leukemia (T-ALL)/ lymphoma (T-LBL) are immature T-cell malignancies with very poor outcomes. In patients with relapsed disease, survival is often < 12 months (Marks et al, Blood, 2009). Prognostic correlates and treatment outcomes after relapse remain largely unknown. Aims: To evaluate prognostic correlates and treatment outcomes in patients with relapsed T-ALL/LBL. Methods: After IRB approval, 92 consecutive patients with T-cell ALL/LBL were identified. 41 patients with relapsed disease after achieving a first complete remission (CR1) were included in the study group. Features at the time of relapse were retrospectively abstracted and analyzed. Survival time after relapse was calculated from the time of relapse until death or last follow-up. Conventional methods were used for statistical analysis. Results: A. Baseline characteristics of all patients 92 patients were identified [41 LBL, 51 ALL]. Median age was 33 years (range; 18-88) and 66 (72%) were males. Median follow-up was 25 months (range 0.9-260). 13(14%) received palliative care or were lost to follow-up before treatment initiation. At last follow-up, there were 41 (52%, n = 79) relapses and 42 (46%, n = 92) deaths. Of 79 patients, 71 (90%) achieved a CR1 and 8 (10%) had primary refractory disease. Comparisons between ALL and LBL revealed expected differences in presenting features such as frequency of primary mediastinal mass at presentation in LBL and high leukocyte count in ALL. Significant differences in treatment were seen. Asparaginase-based and ALL-directed therapy were more common in the ALL group (71% vs. 45%, p = 0.009; 88% vs. 71%, p = 0.04). 13 (81%) LBL and 14 (27%) ALL underwent allogeneic SCT. The remaining three in each group underwent autologous SCT in CR1. B. Characteristics of relapsed patients 41 relapsed after achieving CR1 [23 LBL, 18 ALL]. Median time to relapse was 8.0 months (range 2.3-130), with no difference between ALL and LBL groups. Median age was 34 years (range 19-71) and 29 (71%) were males. Median follow-up after relapse was 7.2 months (range 0.3-207). At time of last follow-up, there were 30 (73%) deaths, 25 (61%) achieved a second complete remission (CR2) and 14 (34%) had persistent disease. 12 (48%) had relapse following CR2. 34 (83%) relapsed following CR1 after induction chemotherapy alone. 6 (15%) and 1 (2%) relapsed following allogeneic and autologous SCT respectively. 27 (66%) had BM involvement, 5 (12%) had CNS involvement, 13 (32%) had mediastinal involvement, and 3 (7%) had isolated extramedullary relapse. Ten (43%) patients with LBL relapsed with ALL. Of 27 patients with available data, 9 (33%) had high-risk cytogenetics at relapse, defined as ≥ 5 chromosomal abnormalities and/or markers known to confer an unfavorable prognosis. 16 of these 27 patients had follow-up cytogenetic studies performed, of which 8 (50%) had evidence of clonal evolution. Patients were treated with up to five regimens. 12 (31%) received asparaginase-based therapy and 13 (33%) received nelarabine with CR2 rates of 75% and 25% respectively. Median number of regimens needed to achieve CR2 was one. 18 (46%) went onto SCT following CR2: 14 (allogeneic), 3 (autologous), and 1 (donor lymphocyte infusion). The majority received myeloablative conditioning (92%). C. Outcomes and prognostic correlates for survival after relapse Median survival following relapse was 8.2 months (IQR 4.1-21.3) and did not differ between LBL and ALL. Nine (36%) who achieved CR2 are alive at time of last follow-up. 25 (61%) achieved CR2, but 12 (48%) relapsed following CR2, with median time to second relapse of 7.6 months (IQR 4.7-14). Nine of 18 who underwent SCT following CR2 had disease relapse (8 allogeneic, 1 autologous). Only BM involvement at relapse significantly correlated with post-relapse survival (HR 2.4 [1.1, 5.1], p = 0.03). Clonal evolution, high-risk cytogenetics, nelarabine therapy, achieving CR2, and SCT were not independent predictors of survival in our small subset of patients. Conclusion: Patients with relapsed T-ALL/LBL have dismal outcomes, in spite of advances in therapy with newer agents such as nelarabine and the use of allogeneic SCT. Regardless of T-ALL/LBL subtype, BM involvement at relapse appears to be a significant factor negatively impacting post-relapse survival. Further studies are needed to validate these findings. Disclosures Al-Kali: Celgene: Research Funding. Thompson:Kite Pharma: Research Funding.

Abstract Background: Myelodysplastic syndrome (MDS) is a heterogeneous disease characterized by cytopenias and a propensity to progress into acute myeloid leukemia in a subset of patients. Clinical trials which led to FDA approval of hypomethylating agents (HMAs) stratified patient's risk status per the IPSS. In 2008, WHO further categorized patients into different groups and the IPSS was revised into the IPSS-R. Therefore, there is a paucity of data regarding the response rates and clinical outcomes of HMA therapy when stratified per WHO subtype and IPSS-R. Goal: We carried this review to assess whether WHO subtypes or IPSS-R had a differential response with corresponding impact on survival. Methods: After IRB approval, all MDS pts who received hypomethylating agents (HMA) (azacitidine or decitabine) with available response data (2000-2014) were included. Clinical characteristics were obtained retrospectively. IPSS-R (Greenberg 2012) was used for risk stratification. Response assessment was based on IWGR 2006 criteria. Statistical comparisons were performed with the χ2 test for categorical variables and the Wilcoxon test for continuous variables. Survival analysis was based on the Kaplan-Meier method and log rank test. For all analyses, P ≤ 0.05 was considered statistically significant. Results: We identified 823 pt in our MDS database; among those that received HMA therapy 70 patients (pts) had evaluable response data. The median age at diagnosis was 67 years (31-85) and 49 (70%) were males. MDS subtypes per WHO 2008 classification were 31(44%) RAEB1/2, 26(37%) RCMD, 10(14%) MDS-U, 2(3%) RARS, and 1(1%) MDS 5q. Fifteen (33%) patients had secondary MDS. 23(32%) developed AML, and median time to leukemic transformation was 14 months (7.8-21). Median time to start HMA was 2.7 months (0-77). Median follow up from initial diagnosis was 20 months (3-118) at which time 22(31%) deaths were documented. A. Patient characteristics: Prior to HMA therapy median laboratory values included; Hemoglobin 9.6 g/dL (6.6-14.8), ANC 1.1 x1010 (0.01-16), Platelet 66 x1010 (4-937), peripheral blast % 0 (0-18), and bone marrow blast % 5 (0-17). IPSS-R for our cohort was as the following, 15(27%) Very high, 14(25%) high, 10(18%) intermediate 12(21%) low, and 5(9%) very low risk. B. HMA Response rates based on WHO subtype: We observed no significant difference in response (p = 0.6) when comparing response rate among different groups. Response rates per WHO subtype were as follows: i. RAEB: 7 (22%) pts achieved CR/Marrow CR, 1(3%) had HI/PR, 17(55%), and 6(20%) had stable disease (SD) and progressive disease (PD), respectively. ii. RCMD: 2 (8%) pts achieved CR/Marrow CR, 4(16%) had HI/PR, 12(46%), and 8(30%) had SD and PD, respectively. iii. MDS-U: 1 (10%) pt achieved CR/Marrow CR, 1(10%) had HI/PR, 6(60%), and 2(20%) had SD and PD, respectively. iv. MDS 5q/RARS: 1(33%) had SD, and the remaining three pts had PD. C. HMA Response rates based on IPSS-R: i. Very low: 1(20%) had HI/PR, 3(60%), and 1(20%) had SD. ii. Low: 2(17%) pts achieved CR/Marrow CR, 3(25%) had HI/PR, 4(33%), and 3(25%) had SD and PD, respectively. iii. Intermediate: 2 (20%) pts achieved CR/Marrow CR, 5(50%), and 3(30%) had SD and PD, respectively. iv. High: 2(14%) pts achieved CR/Marrow CR, 2(14%) had HI/PR, 7(50%), and 3(21%) had SD and PD, respectively. v. Very high: 1(7%) pts achieved CR/Marrow CR, 9(60%), and 5(33%) had SD and PD, respectively. Comparing responses among IPSS-R risk stratification groups, was not statistically significant (p = 0.49). We did not observe a difference in response rate when we further classified pts into low risk (very low, low & intermediate), and high risk (high, very high) (p = 0.27). D. Response effect on Survival: Overall survival was not statistically different among responders (CR/Marrow CR/HI &PR) and non-responder (SD & PD); 22.3 vs 14.7 months respectively (p = 0.21) (Figure1). Conclusion: Using contemporary MDS risk stratification and WHO classification was not predictive of response to hypomethylating agents. Responders did not seem to benefit from prolongation of survival. Given the small sample size in this cohort, this should be further explored in larger groups to identify if there are any potential subgroups that would benefit more from such therapy. Figure 1. Figure 1. Disclosures Al-Kali: Celgene: Research Funding.

Abstract Background: Acute erythroleukemia (AML-M6) is an aggressive myeloid leukemia, with poor outcomes (median survival < 12months). In 2008, the WHO further sub-classified this disease into two subgroups- erythroid leukemia and pure erythroid leukemia, based on the number of erythroblasts and myeloblasts. We carried out this study to evaluate differences in presenting features and outcomes between erythroid leukemia and pure erythroid leukemia. Methods: After due IRB approval, out of 923 AML, 43(4.6%) pts who met the 2008 WHO criteria for acute erythroleukemia (2000-2014) were identified, and clinical characteristics retrospectively reviewed. A diagnosis of erythroid leukemia (M6a) was considered if > 50% of the total nucleate BM cells were of erythroid lineage and > 20% of non-erythroid cells were myeloblasts. Pure erythroid leukemia (M6b) was diagnosed in pts who presented with > 80% of BM nucleate cells consisting of immature erythroid precursors. Cytogenetic risk stratification was based on NCCN AML guidelines. Statistical comparisons were performed with the χ2 test for categorical variables and the Wilcoxon test for continuous variables. Univariate and multivariate analyses were performed with the Cox logistical regression. Survival analysis was based on the Kaplan-Meier method and log rank test. For all analyses, P ≤ 0.05 was considered statistically significant. Results: The median age at diagnosis was 65 years (27-90) and 34(79%) were male. 30 (69%) had M6a and 13 (30%) had M6b. 27 (62%) had de novo AML M6, whereas 16 (37%) had secondary AML (9 underlying MDS and 7 therapy related).The median time to leukemic transformation for pts with underlying MDS was 8 months (2-83). Median follow up in our cohort was 7.2 months (2-157) at which time 13 (30%) deaths were documented. A. Patient characteristics: At time of diagnosis median laboratory values included; Hemoglobin 8.5 g/dL (4.6-11), WBC 2x109 (0.7-11.1), ANC 0.47x109 (0.01-4.07), Platelet 33x 109 (7-177), peripheral blast % 2 (0-35), and bone marrow blast % 11 (0-84). Cytogenetic information was available in 38 pts; of which 6(16%) were diploid, 21(55%) were complex/monosmal and 1(3%) was complex/non monosomal. Intermediate risk cytogenetic was observed in 15 pts (39%), and poor risk cytogenetic was identified in 23(61%). Comparing M6a and M6b, we observed that pts with M6a tend to have more leukopenia and neutropenia and higher marrow blast percentage compared to M6b (Table 1). None of the patients experienced extramedullary disease or CNS involvement. B. Outcome and prognostics: We did observe a trend towards worse survival in pts with M6b, 7 months vs 12.9 months with M6a (p= 0.08) (Figure 1). There was no difference in survival in acute erythroleukemia compared to other acute myeloid leukemias, 10.1 vs 14 months (p= 0.28), respectively (Figure 2). In univariate analysis, WBC, ANC, and cytogenetic risk impacted survival (Table 2), however only cytogenetic risks retained significance in the multivariate model; Intermediate risk HR 0.18 (0.05-0.51; p = 0.0009) and poor risk HR 5.4 (1.9-17.6; p = 0.0009). Conclusion: Acute Erythroid Leukemia is a rare leukemia with ~5% incidence in our cohort. We observed that regardless of the percentage of bone marrow erythroblasts and myeloblasts, survival in patients with Acute Erythroleukemia are predominantly impacted by cytogenetic risk stratification. This raises a question on the clinical relevance of the sub-categorization of acute erythroleukemia into erythroid leukemia and pure erythroid leukemia. Larger studies are needed to validate our results. Figure 1. Figure 1. Disclosures Al-Kali: Celgene: Research Funding.

Abstract Background: Acute myeloid leukemia (AML) is an aggressive form of blood cancers with a wide range of response and relapse rates using standard chemotherapy regimen (commonly known as 7+3). Several genes (FLT3, IDH1, RAS) have been targeted using small molecule tyrosine kinase inhibitors with encouraging results. The stem cell receptor tyrosine kinase KIT is expressed more than 10% in the blasts in 95% of relapsed AML cases and mediates leukemic proliferation and has anti-apoptotic effects (Domen and Weissman 2000). AML with high KIT expression is associated with poorer outcome (Del Poeta, Venditti et al 2003). Goals: To study the efficacy and safety of combination 7+3 and nilotinib in patients (pts) with AML and KIT expression. Primary goal is to determine the complete response (CR) rate; while secondary goals include 2-year overall survival (OS) and disease free survival (DFS) in addition to safety of DATA regimen. Methods: A single arm, Phase II study, enrolled pts at Mayo Clinic (MN and AZ). Appropriate IRB was obtained and study was registered (NCT 01806571). Pts were enrolled if they were newly diagnosed with AML with KIT (CD117) expression of 20% or higher on myeloblasts by flow cytometry. KIT mutations were allowed if present. Nilotinib 300 mg twice daily was given on days 4-14 of induction and consolidation; and continuous daily maintenance therapy for up to 2 years. Cytarabine 100 mg/m2/day continuous IV x7 days plus daunorubicin 60 mg/m2 IV daily x3 days were used for induction , while consolidation used standard cytarabine 3 gm/m2 twice daily days 1, 3, 5 for a total of 4 cycles. This is a Simon 1-stage design with a safety analysis after enrolling 12 pts, and an interim analysis after enrolling 18 out of 43 pts. If 11 or fewer pts achieve complete remission, the regimen will be considered ineffective. Results: Eighteen pts have been enrolled between July 2013 and July 2015, 17 of which have baseline data. Median age was 58 years (range 24-65) with 76.5% being male. Median laboratory findings include hemoglobin of 9.3 gm/dL, platelets of 52 x109, and white blood count of 7.0 (0.5-125). Cytogenetics were normal in 41% of the pts. Favorable cytogenetics were seen in 2 pts (inv 16). FLT3 testing was done on 15 pts and was positive in 27%. KIT gene sequencing (exon 8, 9, 10, 11, 17) revealed no pathogenic mutation. Median number of cycles was 3 (range 1-7). Six pts had treatment delays, with 2/13 (15%) delays being due to non-hematologic toxicities. No delays or missed doses affected cytarabine and daunorubicin administration. Out of 15 pts evaluable for response, 12 (80%) achieved CR (or CR with incomplete platelet recovery). Six of the 12 pts (50%) who achieved remission needed a second induction on protocol. Two out of 15 did not respond (did not get re-induction on protocol). One pt died before disease assessment due to liver failure (G5, had only one dose of nilotinib and toxicity was attributed to daunorubicin). Of the 14 pts having at least 1 bone marrow biopsy, the overall CR rate was 86%. Five (33%) pts proceeded to allogeneic stem cell transplant, all are alive and none were able to initiate protocol nilotinib maintenance therapy. Only 2 out of 12 (17%) pts relapsed after achieving CR, one was secondary AML from myelodysplastic syndrome with complex karyotype and the other was therapy-related AML with t(9;11). Only 2 (11%) pts died at time of report. Thirteen pts were evaluated for adverse events (AE). Six pts had G4 non-hematological AEs. Five of 12 G4 AEs were related to infection, 2 were electrolyte imbalances, and 2 were heart failures. Most common G3 non-hematological AEs were febrile neutropenia (53%), hypophosphatemia (23%), hyperglycemia (23%), and hypertension (23%). In agreement with the favorable outcomes, the molecular target validation revealed that nilotinib treatment down-regulates the expression of KIT, Sp1, DNA methyltransferase (DNMT) 1, DNMT3a and DNMT3b. Conclusion: Combination daunorubicin and cytarabine with nilotinib (DATA) appears to be safe and effective. Interim results show an acceptable safety profile in the first 12 evaluable pts with most common AE being infection as expected. Thirty day mortality is acceptable (7%). DATA regimen has encouraging CR rates of 80% (intent to treat) and 86% in assessed pts, with half of the pts who achieved remission requiring 2 cycles of induction. Relapse rate seems to be low at 17%. We will continue accrual until all pts accrued for final results. Disclosures Al-Kali: Celgene: Research Funding. Off Label Use: This is a Phase II study of combination nilotinib to standard chemotherapy in patients diagnosed with AML.. Tibes:TetraLogic Pharmaceuticals: Research Funding.

Abstract Background:Morphologic complete remission (CR) is the gold standard for assessing response in acute myelogenous leukemia (AML). CR with incomplete count recovery (CRi) and CR with incomplete platelet recovery (CRp) are associated with inferior overall survival post induction therapy (Walter et al, JCO 2010 and Chen et al, JCO 2015). Furthermore, residual cytogenetic disease is associated with a higher relapse compared with patients with cytogenetic CR (CCR; Chen et al, JCO 2011). There is a paucity of literature regarding the impact of CRi, CRp and CCR prior to allogeneic transplantation. Aim:To study the impact of CRi, CRp and CCR and their impact on relapse incidence (RI), non-relapse mortality (NRM) and overall survival (OS) in reduced intensity allogeneic stem cell transplantation (RIC-SCT). Methods:After due IRB approval, patients (pts) with acute myelogenous leukemia (AML) or myelodysplastic syndrome (MDS) who received RIC-SCT at our institution between 2008-2014 were identified. All clinical and pathologic data were retrospectively extracted. CR, CRi, CRp and CCR were defined in accordance to the international working group definition. Categorical and continuous variables were analyzed using Pearson's chi-squared and Wilcoxon/Kruskal-Wallis, respectively. Survival estimates were calculated using the kaplan-meier and log-rank test. RI was estimated on a competing event analysis using Grey's model. Cox proportional regression was used to compute hazard ratios (HR). Results: A. Baseline characteristics: A total of 134 patients were identified. A total of 70 (52%) were in CR, 40 (30%) in CRi and 24 (18%) in CRp. 129 patients had evaluable cytogenetic data pre-SCT; 81 (63%) were in CCR and 48 (37%) had persistent cytogenetic disease. Baseline patient, disease and transplant characteristics stratified by peripheral count recovery pre-SCT are shown (Table 1). Significantly more patients in CR had higher KPS, higher proportion AML diagnosis, more likely to be in first complete remission (CR1), higher rate of cytogenetic CR and a higher proportion of minor ABO mismatched donor. No other significant variables were identified between the three cohorts. B. Transplant outcomes: Median follow up of the entire cohort was 41.9 months and the 2-yr OS, RI and NRM were 61.7%, 25.7% and 21.9%. Patients in CR, CRi and CRp had a similar 2-year rates of RI (26.3%, 18.4% and 28.9%, respectively; p = 0.66), 2-year NRM (20.5%, 38.8% and 22.1%, respectively; p = 0.18) and 2-year OS (61.8%, 55.1% and 58.6%, respectively; p = 0.82). RI was significantly lower for patients in CCR pre-SCT with HR 0.25 (95% CI 0.11-0.51 p = 0.0001) without a difference in overall survival HR 0.68 (0.41-1.15; p = 0.14). However, we observed a similar RI in CR, CRi and CRp patients who had persistent cytogenetic disease pre-SCT (p = 0.55). The outcome remained similar between strata after excluding MDS patients (data not shown). Conclusion: We observed equivalent post-transplant outcomes between CR, CRi and CRp despite the presence of persistent cytogenetic disease. This suggests that RIC SCT had a role in mitigating the negative prognosis associated incomplete hematologic recovery. These findings have implications as physicians may not need to postpone SCT to await count recovery. This important question should be further validated in a larger cohort of patients. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Al-Kali: Novartis: Research Funding.