Hogan, William J.

Abstract No laboratory test can predict non-relapse mortality (NRM) after hematopoietic cellular transplantation (HCT) prior to the onset graft-versus-host disease (GVHD). Recently, we have shown that a signature of three GVHD plasma biomarkers (TNFR1, ST2, and REG3α) can predict response to GVHD therapy and NRM at the onset of clinical GVHD (Levine, Lancet Haem, 2015). Our goal in the current study was to identify a blood biomarker signature that could predict lethal GVHD and six-month NRM well in advance of the onset of GVHD symptoms. Patient samples on day +7 after HCT were obtained from 1,287 patients from 11 HCT centers in the Mount Sinai Acute GVHD International Consortium (MAGIC). Samples from two large centers (n = 929) were combined and randomly assigned to a training set (n = 620) and test set (n = 309). 358 patients from nine others centers constituted an independent validation set. The overall cumulative incidences of 6-month NRM were 11%, 12%, and 13% for the training, test, and validation sets respectively. The incidence of lethal GVHD, defined as death without preceding relapse while under steroid treatment for acute GVHD, were 18%, 24%, and 14% in the same groups, respectively. The median day of GVHD onset was 28 days in the training set and 29 days in the test and validation sets. We measured four GVHD related biomarkers [ST2, REG3α, TNFR1, and IL2Rα] in all samples and used the training set alone to develop competing risks regression models that used all 13 possible combinations of one to four biomarkers to predict 6-month NRM. The best algorithm, which we rigorously confirmed through Monte Carlo cross-validation of 75 different combinations of training sets, included ST2 and REG3α. No combination of one, three, or four biomarkers was superior to the combination of these two biomarkers. The day 7 algorithm identified high risk (HR) and low risk (LR) groups with 6-month NRMs of 28% and 7%, respectively (p<0.001) (Fig 1A). The relapse rates did not differ between risk groups so that overall survival (OS) was 60% for HR and 84% for LR (p<0.001) (Fig 1B). When applied to the test set (Fig 1C/D), the algorithm identified 54/309 (17%) of the patients as HR with an NRM of 33% vs 7% for LR patients (p<0.001) and 6-month OS of 57% and 81% for HR and LR patients, respectively (p<0.001). In the independent validation set (Fig 1 E/F), the algorithm identified 72/358 (20%) of the patients as HR with an NRM of 26% vs 10% for LR patients (p<0.001) and OS of 68% and 85% for HR and LR patients, respectively (p<0.001). High risk patients were three times more likely to die from GVHD than LR patients in each cohort (p<0.001) (Fig 2). The GI tract is the GVHD target organ that is most resistant to treatment and represents a major cause of NRM, and we observed twice as much severe GI GVHD (stage 3 or 4) in HR patients as in LR patients (p<0.001, data not shown). The algorithm successfully separated HR and LR strata for 6 month NRM in several groups with differing risks for GVHD and NRM, including donor type, degree. of HLA-match, age group, and conditioning regimen intensity (Fig 3). In conclusion, we have developed a blood biomarker algorithm that predicts the development of lethal GVHD seven days after HCT, which performed successfully in large multicenter validation sets. The GVH reaction is already in progress by day +7, even though clinical symptoms may not occur until days or weeks later. We speculate that the blood biomarker concentrations at this early time point reflect subclinical GI pathology, a notion that is reinforced by the fact that ST2 and REG3α, the two biomarkers in the algorithm, are closely associated with GI GVHD. The algorithm identified HR and LR strata in several patient groups with different overall risk for lethal GVHD (donor, HLA match, conditioning regimen intensity, age). This day +7 algorithm should prove useful in clinical BMT research by identifying patients at high risk for lethal GVHD who might benefit from aggressive preemptive treatment strategies. Disclosures Chen: Novartis: Research Funding; Incyte Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Jagasia:Therakos: Consultancy. Kitko:Therakos: Honoraria, Speakers Bureau. Kroeger:Novartis: Honoraria, Research Funding. Levine:Viracor: Patents & Royalties: GVHD biomarkers patent. Ferrara:Viracor: Patents & Royalties: GVHD biomarkers patent.

Abstract Background: Molecular profiling has revolutionized the field of hematology, and in particular myeloid neoplasms. NPM1+/FLT3- mutational status has been shown to have a favorable prognostic impact in patients with acute myeloid leukemia (AML). However, little is known about its interaction with age. Methods: We retrospectively analyzed the overall survival (OS) in newly diagnosed AML patients, whose FLT3 and NPM1 data were available, and were treated with cytotoxic chemotherapy at our institution between 2003 and 2013. Patients 18 to 60 years of age were categorized as adult, and those above 60 years were classified as elderly. Each of the elderly or adult groups were further divided according to the presence or absence of combined NPM1+/FLT3- mutational status. Estimated probabilities of overall survival were calculated using the Kaplan-Meier method, with the log-rank test to compare groups. Demographics and continuous variables were compared using the Wilcoxon rank sum test. Appropriate IRB approval was obtained. Results: Out of 835 patients with AML, 86 patients with both known FLT3/NPM1 mutation status and receiving induction chemotherapy were found. NPM1+/FLT3- mutational status was present in 11 elderly (median age 68 yr, hemoglobin (Hb) 8.7 g/dL, white blood cells (WBC) 9.6 x109/L, platelets (PLT) 100 x109/L, peripheral blood blasts percentage (PB%) 31), and in 11 adult patients (median age 49 years, Hb 9.1 g/dL, WBC 14 x109/L, PLT 67 x109/L, and PB% 21). Twenty-eight elderly patients (median age 66 yr, Hb 9.4 g/dl, WBC 15.7 x109/L, PLT 66 x109/L, and PB% 33), and 36 adult patients (median age 49 years, Hb 9.1 g/dL, WBC 14 x109/L, PLT 67 x109/L, and PB% 21) were carrying genotypes other than NPM1+/FlT3-. There was no statistical significant difference in the median age, Hb, WBC, PLT, and PB% at the time of diagnosis. Out of 86 patients, 79 had intermediate, 6 had adverse, and 1 had favorable cytogenetic risk. All elderly and adult patients with NPM1+/FLT3- genotype had intermediate risk cytogenetics. When treated with cytotoxic chemotherapy, elderly patients with NPM1+/FLT3- genotype demonstrated a significantly better overall survival compared to elderly patients without this genotypes (p=0.015), and interestingly also to adult AML carrying other genotypes (p=0.028). Surprisingly, there was not an improved survival in adults with NPM1+/FLT3- genotype compared to adults carrying other genotypes (p=0.14), but this may have been related to the small numbers in each group. No significant difference in the overall survival was observed between elderly and adult patients who were carrying NPM1+/FLT3- mutational status (p=0.4). The estimated 5-year survival rates for elderly with and without NPM1+/FLT3- status were 71% vs. 14%, and for adults with and without this genotype were 49% vs. 19%, respectively. Conclusion: Age does not have an impact on the OS in AML patients with NPM1+/FLT3- mutational status, arguing strongly for intense chemotherapy in this group. Elderly AML patients with NPM1+/FLT3- genotype have a superior OS compared to both adult and elderly patients carrying other genotypes, when treated with cytotoxic chemotherapy. Further validation in large prospective studies is warranted. Figure 1 Figure 1. Figure 2 Figure 2. Disclosures No relevant conflicts of interest to declare.

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 Clinical GVHD staging varies between centers and is not agreed upon by independent reviewers (Weisdorf, BBMT 2003). These inconsistencies help explain why promising GVHD treatments from single center studies have not reproduced in multicenter trials. To address this issue, our international GVHD research consortium has developed guidance that has been refined through consensus following case discussions, resulting in uniform and reproducible GVHD clinical symptom reporting. We record all raw target organ symptom data and apply staging based upon this data (Table 1). Only areas of erythema, bullae and desquamation are quantified because other skin changes are not typical of active GVHD rash. Upper GI symptoms must meet thresholds to diagnose GVHD: anorexia with associated weight loss, nausea and/or 2+ vomiting episodes/day lasting 3+ days. For lower GI GVHD we collect stool volumes excluding formed/mostly-formed stools. Unquantified episodes are counted at 200 ml per episode (3 ml/kg for children <50kg) based upon a chart review of 300 patients with post-BMT diarrhea from any cause. Non-GVHD rectal bleeding that results in flecks or streaks of blood in the stool are ignored for staging. We use the highest daily stool output in the 3 days prior to the diagnosis of lower GI GVHD to determine onset stage and, when available, a 3-day average stool volume for subsequent staging to smooth daily variability. We classify biopsy report interpretation into four standardized categories: Positive (unequivocal presence of GVHD), Equivocal (findings suggestive of GVHD, but the pathologist cannot confirm the diagnosis), Non-diagnostic (no abnormalities or subtle findings insufficient to determine etiology), and Non-GVHD etiology (definitive evidence of another diagnosis without concomitant features suggestive of GVHD). We then combine the biopsy interpretation with clinical decision making to assign an overall confidence level to the diagnosis of GVHD in each target organ (Table 2): Confirmed (positive biopsy, regardless of clinician treatment decision), Probable (GVHD diagnosis is sufficiently favored that treatment is given without a positive biopsy), Possible (symptoms present without a positive biopsy; not treated as GVHD), Negative (no symptoms or symptoms are present but a GVHD diagnosis is not entertained and a non-GVHD etiology is identified). Uniform clinical data collection is essential for future GVHD trials and requires application of clear guidance. While still subject to refinement, these guidelines, in use for 2 years by an international research consortium, are designed to be clear, easy to apply, and for clinical trial use. Table 1. GVHD Target Organ Staging Stage Skin (active erythema only) Liver (bilirubin) Upper GI Lower GI (stool output/day) 0 No active (erythematous) GVHD rash < 2 mg/dl No or intermittent nausea, vomiting or anorexia Adult: < 500 ml/day or <3 episodes/day Child: < 10 ml/kg/day or <4 episodes/day 1 Rash < 25% BSA 2-3 mg/dl Persistent nausea, vomiting or anorexia Adult: 500-999 ml/day or 3-4 episodes/day Child: 10 -19.9 ml/kg/day or 4-6 episodes/day 2 Rash 25 - 50% BSA 3.1-6 mg/dl - Adult: 1000-1500 ml/day or 5-7 episodes/day Child: 20 - 30 ml/kg/day or 7-10 episodes/day 3 Rash > 50% BSA 6.1-15 mg/dl - Adult: >1500 ml/day or >7 episodes/day Child: > 30 ml/kg/day or >10 episodes/day 4 Generalized rash (>50% BSA) and bullous formation or desquamation > 5% BSA >15 mg/dl - Severe abdominal pain with or without ileus, or grossly bloody stool (volume independent) Table 2. Confidence Levels Pathologic evidence Clinician assessment Treatment for acute GVHD Comments Confirmed Unequivocal evidence of GVHD GVHD is the etiology for symptoms Not required GVHD is clearly present even if other etiologies co-exist simultaneously Probable Not required (includes equivocal and non-diagnostic biopsies) GVHD most likely etiology for symptoms Yes GVHD is most likely present but other etiologies may also explain the symptoms and there insufficient evidence to make a confirmed diagnosis Possible GVHD in differential diagnosis (but no treatment is being provided) No GVHD may be present, but other etiologies are favored Negative Unequivocal evidence of a diagnosis other than GVHD (e.g., drug rash) GVHD is not considered as an explanation for the symptoms No and the symptoms resolve without GVHD treatment A "negative" biopsy (e.g., normal skin) is not unequivocal evidence of a diagnosis other than GVHD Disclosures Devine: Genzyme: Research Funding. Chen:Bayer: Consultancy, Research Funding. Porter:Novartis: Patents & Royalties, Research Funding. Levine:Novartis: Consultancy.

Abstract Background : CC-5013 (Revlimid™) is an immunomodulatory analog of thalidomide that is substantially more potent than the parent drug in terms of both anti-angiogenic and anti-TNF-α activity. CC-5013 has shown therapeutic activity in thalidomide-responsive hematological malignancies including relapsed multiple myeloma (Blood2002;100:3063) and myelodysplastic syndrome (Blood2002;100:96a). Myelofibrosis with myeloid metaplasia (MMM) has also been shown to respond to thalidomide (BJH2002;117:288). Furthermore, both angiogenesis and altered TNF-α activity have been pathogenetically implicated in MMM. Methods : The current report considers the first 15 patients in an ongoing phase II treatment trial of single agent CC-5013 in MMM based on a minimum of 3 month follow-up from day 1 of protocol treatment. Study eligibility criteria included no concomitant MMM-directed therapy, a hemoglobin (Hgb) level of < 10 g/dL, an absolute neutrophil count (ANC) of ≥ 1 x 109/L, and a platelet count of ≥ 100 x 109/L. Previous thalidomide therapy in the absence of high-grade skin toxicity was allowed. All patients were started with daily oral CC-5013 (10 mg/day) to be taken for three 28-day treatment cycles. Three additional treament cycles were planned in case of anemia response. Results : Median age was 64 years (range, 40–75) and 10 pts were males. Twelve of the 15 study pts (80%) were red cell transfusion-dependent, 14 (93%) were previously treated including 12 with cytoreductive and 4 with thalidomide therapy. The spleen was palpably enlarged in 13 pts (median 18 cm, range 7–23). Eight of the 15 pts (53%) successfully completed 3 months of protocol treatment. Treatment was discontinued in the remaining 7 pts because of drug toxicity (2 pts), disease progression (1 pt), other co-morbid condition (3 pts), or patient discretion (1 pt). Treatment response data : Clinically relevant responses were documented in 4 patients (27%) and consisted of measurable improvements in anemia (2 pts), splenomegaly (2 pts), and/or constitutional symptoms (3 pts). One pt experienced an increase in Hgb level from 8.3 to 13.4 g/dL, a decrease in leukocyte count from 66.2 to 7.7 x 109/L, and complete resolution of myelophthisis including disapperance of circulating blasts that measured 9% before treatment. Another pt became transfusion-independent (Hgb level increased to > 10 g/dL) as well as enjoyed a profound improvement in constitutional symptoms. Interestingly, serum lactate dehydrogenase (LDH) level decreased in 11 pts (73%) to either within the normal ramge (5 pts) or by more than 30 % (6 pts). Treatment toxicity data : Grade 3 or 4 adverse events that were possibly, probably, or definitely attributed to CC-5013 included rash (2 pts), neutropenia (5 pts), thrombocytopenia (3 pts), and fatigue (2 pts). In addition, 3 patients experienced drug-associated extreme thrombocytosis while a histologically-proven disseminated extramedullary hematopoiesis was documented in one patient after one month of CC-5013 treatment. Conclusion : The current preliminary report suggests a substantial biological activity of CC-5013 in MMM with a therapeutic potential for a subset of patients. Additional studies with a longer duration of therapy, different dose schedules, and combinations of CC-5013 and corticosteroids are warranted.

Abstract Background : Momelotinib (a JAK1 and JAK2 inhibitor) induces both anemia and spleen response in patients with myelofibrosis (MF) (Leukemia 2013;27:1322). The favorable effect on anemia was a distinguishing feature for momelotinib, compared to other JAK inhibitors, but the drug was also associated with treatment-emergent peripheral neuropathy (TE-PN). We examined the natural history and risk factors of momelotinib-associated peripheral neuropathy. Methods : The study patients constitute part of a larger phase-1/2 clinical trial (CCL09101; NCT00935987) using momelotinib for the treatment MF. Toxicity grading was according to the Common Terminology Criteria for Adverse Events (CTCAE) v.4.03. Momelotinib capsules (as opposed to the newer tablet formulation used in the currently ongoing phase-3 study) were used in the current study, which represents a sponsor-independent analysis. Results : 100 patients with MF (median age 66 years; 58% males) were treated at the Mayo Clinic between 11/20/09 and 11/10/10. DIPSS-plus (JCO. 2011;29:392) risk distribution was 63% high, 36% intermediate-2 and 1% intermediate-1. 75% of the patients harbored JAK2V617F and 50% abnormal karyotype. Previous treatment included other JAK inhibitors in 21 patients, thalidomide/lenalidomide/pomalidomide in 31 and hydroxyurea or other cytoreductive agents in 55. History of diabetes was documented in 7% of the patients at baseline and 14 (14%) of the patients had symptoms of PN before starting treatment with momelotinib, all of which were grade-1. Momelotinib was initiated at 100 mg/day in 3 patients, 150 mg/day in 21, 150 mg twice-daily in 20, 200 mg/day in 3, 300 mg/day in 47 and 400 mg/day in 6. The maximum momelotinib dose was 150 mg/day in 6 patients, 150 mg twice-daily in 20, 300 mg/day in 68 and 400 mg/day in 6. Treatment duration was <6 months in 12 patients, 6-12 months in 22, 12-24 months in 19 and >24 months in 47. Median follow-up after the institution of protocol drug therapy was 35 months (range 1-49). During this period, TE-PN was documented in 44 (44%) patients; of these, 42 were in patients without baseline neuropathy. TE-PN involved the feet only in 28 patients, hands only in one patient and both feet and hands in 15 patients. Median (range) for the time of onset of TE-PN was 32 weeks (1-132) and duration of TE-PN 11 months (0-40). All 42 newly-emergent PN were grade-1 sensory while the two patients with grade-1 baseline PN progressed to grade-2. Formal neurological evaluation, which was performed in 9 patients, mostly showed length-dependent sensory-motor large and small fiber neuropathy with axonal features. TE-PN resulted in drug discontinuation in 7 patients and reduction in drug dose in 28 patients. Improvement after drug dose reduction was documented in only one patient and in none of those with drug discontinuation. Progression to grade-2 PN was documented in 3 patients. TE- PN was significantly associated with clinical improvement (CI) with 54% incidence in responders vs 30% in non-responders (p=0.02); however, longer treatment duration was also associated with higher prevalence of TE-PN (p=0.03). In univariate analysis, patients with TE-PN lived longer than those without TE-PN (p=0.048); however, significance was lost during multivariable analysis that included either achievement of CI or treatment duration. Neither the initial (p=0.53) nor maximum (p=0.37) momelotinib dose was correlated with TE-PN, which was also not influenced by JAK2V617F (p>0.99), karyotype (p=0.26), history of diabetes (p=0.39) or previous treatment with JAK inhibitor therapy (p=0.7), thalidomide (p=0.24), lenalidomide (p=0.59), pomalidomide (p=0.63) or hydroxyurea (p=0.56). There were no correlations between TE-PN and age (p=0.37), sex (p=0.37), type of MF (p=0.98), DIPSS-plus score (p=0.07), baseline transfusion dependency (p=0.15), constitutional symptoms (p=0.83) or spleen size (p=0.53). TE-PN did not correlate with hematologic (p=0.14) or extramedullary toxicity other than PN (p=0.41) or lipase/amylase abnormalities (p=0.35). Conclusions : Momelotinib-associated neuropathy in MF might not be reversible in the majority of cases but also does not appear to be progressive. We were not able to identify risk factors for TE-PN, other than duration of treatment, which also explains its apparent association with response/survival. We are currently looking into possible correlations with serum thiamine levels. Disclosures No relevant conflicts of interest to declare.

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.

Abstract Abstract 4252 Background: Multiple recent studies have demonstrated the survival benefits of reduced intensity allogeneic stem cell transplant for high risk CLL patients. These transplant series, however, represent highly selected cases where age, co-morbidities and performance status preclude transplant in many patients with CLL. The portion of newly diagnosed CLL patients that are eventually considered for transplant is unknown, as well as the proportion that are referred for transplant evaluation; the proportion that actually receive stem cell transplant, and the reasons for not pursuing transplant in referred patients. We conducted a cohort study of newly diagnosed CLL patients to address this gap in knowledge. Methods: We used the Mayo Clinic database to identify all patients with newly diagnosed CLL seen at Mayo Clinic within 1 year of diagnosis between July of 2003 and May of 2011 (time interval during which reduced intensity allogeneic stem cell transplantation was part of routine care at Mayo Clinic). Electronic medical record and laboratory studies were reviewed to identify all patients referred for stem cell transplant evaluation (either allogeneic transplant for progressive CLL or autologous stem cell transplant for Richter's transformation). Patients referred for transplant were analyzed to determine what proportion completed transplant and, for those who were not transplanted, the reason they were not transplanted (e.g. lack of insurance approval, co-morbidity, lack of a donor, inadequate disease control, death prior to transplant or patient preference). Results: A total of 1250 patients with newly diagnosed CLL between July 2003 and May 2011 who were seen at Mayo Clinic within 1 year of diagnosis were identified. The mean age at diagnosis was 63.6 yrs and 34.2% were women. With respect to disease stage, 48.7% were Rai stage 0, 45.5% Rai stage I/II, and 5.8% Rai stage III/IV. CLL FISH analysis revealed 126 (13.6%) patients who had either del (17p) or del (11q) and 801 (86.4%) patients who had other FISH abnormalities or normal FISH results. After a median follow-up of 41 months, 425 (34%) of patients have received treatment. A total of 54 patients (4.3%) were referred for a transplant evaluation during follow-up. Of these 54 patients, 48 (3.8% overall cohort) were referred for consideration of allogenic transplant for treatment of progressive CLL and 6 (0.5%) were referred for autologous transplant for treatment of Richter's transformation. Baseline characteristics associated with subsequent transplant referral included age at diagnosis (median: 56 yrs) (p &lt; 0.0001, Odds Ratio (OR) for each year older = 0.91, 95% Confidence Interval (CI)=(0.88, 0.95)), Rai stage (III/IV vs. 0) (p = 0.0002, OR = 22.7, 95% CI=(5.1, 102.4)) and FISH (del(11q), del(17p) vs Normal, del(13q) or Trisomy 12) (p &lt; 0.0001, OR = 7.3, 95% CI=(3.3, 16.1)). Gender, Rai stage (I/II vs. 0), and patient residence (local vs. not local) were not significant. Among the 54 patients referred for transplant, 28 (51.9%) completed a transplant. This included 22 (45.8%) patients referred for allogenic transplant and 6 (100%) patients referred for autologous transplant. Among the 26 patients referred who did not undergo transplant, the principal reasons were patient preference (n = 6, 23.1%), patient still being evaluated for transplant as of the study end date (n = 6, 23.1%), alternative therapy chosen (n = 5, 19.2%), inadequate disease control (n = 3, 11.5%), death prior to transplant (n = 3, 11.5%), lack of insurance approval (n = 2, 7.7%), and lack of a donor (n = 1, 3.8%). Conclusion: 4.3% of the newly diagnosed CLL patients in this series were considered for stem cell transplant at some point during follow-up. Young age, high Rai stage and high risk FISH abnormalities are principal reasons for transplant referral. Only 51.9% of those considered for transplant completed transplant. The principal reasons for referral patients not completing transplant who had adequate time to follow were patient preference, alternative therapy, inadequate disease control and death prior to transplant. The remaining 6 patients (23%) are in process of transplant evaluation with longer follow required. These analyses provide first incidence data for CLL transplant referral in a cohort of newly diagnosed patients. Disclosures: Zent: Biothera: Research Funding; Genzyme: Research Funding; Genentech: Research Funding; Novartis: Research Funding; GlaxoSmithKlime: Research Funding. Shanafelt:Celgene: Research Funding; Teva/Cephalon: Research Funding; GlaxoSmith Klein: Research Funding; Genentech: Research Funding; Hospira: Research Funding; Polyphenon E International: Research Funding.

Abstract Abstract 739 The combination of a calcineurin inhibitor and methotrexate has been the standard of care in graft-vs.-host disease (GVHD) prophylaxis for over 25 years, with resultant rates of grade II-IV acute GVHD between 30–50%. The mTOR inhibitor, sirolimus, has demonstrated promise in a number of Phase II trials as an immunosuppressant used for GVHD prophylaxis. The BMT CTN, sponsored by the NHLBI and NCI, conducted a multicenter, randomized controlled trial comparing the combination of tacrolimus and sirolimus (Tac/Sir) with tacrolimus and methotrexate (Tac/Mtx) as GVHD prophylaxis after matched, related donor (MRD) hematopoietic stem cell transplantation (HSCT). Methods: Eligible patients were between ages 2 – 60 years, and had acute leukemia in remission, myelodysplasia or chronic myeloid leukemia in chronic or accelerated phase. All had adequate organ function, and a 6/6 HLA-A, B, DRB1 matched sibling donor. 304 patients were randomly assigned to either Tac/Sir (n = 151) or Tac/Mtx (n = 153) as GVHD prophylaxis after TBI-based conditioning and MRD HSCT. An intent-to-treat analysis was performed on the primary endpoint of Grade II-IV GVHD-free survival 114 days from randomization. Ten subjects who received busulfan-based conditioning and were previously reported were excluded from analysis. Three subjects who did not undergo HSCT are included in the primary analysis, but not secondary analyses. Results: Treatment groups were well balanced. The median age of participants was 44 years (range 13 – 59) and 83% had acute leukemia. Neutrophil and platelet engraftment were both faster in the Tac/Sir group (14 vs. 16 days, p < 0.001; 16 vs. 19 days, p = 0.03, respectively), but this did not affect the time to first hospital discharge (20 vs. 21 days, p = 0.37). The incidence of grade II-IV and grade III-IV acute GVHD at 100 days were lower in the Tac/Sir group (26 vs. 34%, p = 0.17; 8 vs. 15%, p = 0.05). Day 100 treatment-related mortality was no different between groups (7 vs. 7%, p = 0.43). The primary endpoint of 114-day acute GVHD-free survival was not statistically different between groups (67 vs. 62%, p = 0.38, Figure). The cumulative incidence of relapse at 2 years from transplantation was not different between groups (27 vs. 30%, p = 0.81). The competing-risk cumulative incidence of chronic GVHD was higher in the Tac/Sir arm (54 vs. 43%, p =0.044). Overall toxicities were not different between groups, with two notable exceptions. The peak and average OMAS oral mucositis scores were lower in the Tac/Sir arm (peak 0.70 vs. 0.96, p < 0.001; average 0.31 vs. 0.47, p < 0.001), however, there was an increased rate of the endothelial injury syndromes, veno-occlusive disease (11 vs. 4%, p = 0.03), and thrombotic microangiopathy (5 vs. 1%, p = 0.05) in the Tac/Sir arm. Causes of death were not different between groups. At 2 years from transplantation, disease-free (DFS) and overall survival (OS) were not different between study arms (DFS 53 vs. 53%, p = 0.76; OS 60 vs. 61%, p = 0.44). Conclusions: No difference in 114-day acute GVHD-free survival was noted between treatment arms. Compared with Tac/Mtx in MRD HSCT, Tac/Sir is associated with more rapid engraftment, less severe acute GVHD and oral mucositis, excess chronic GVHD and endothelial injury syndromes, and similar long-term outcomes. Understanding the trade-offs between regimens, Tac/Sir can be used as an alternative to Tac/Mtx in MRD HSCT. Disclosures: Cutler: Pfizer, inc: Research Funding; Astellas, Inc: Consultancy, Research Funding. Off Label Use: Sirolimus - Prevention of GVHD Tacrolimus - Prevention of GVHD. Waller:Outsuka: Research Funding.