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Recipient chimerism increase has been used to predict leukemia relapse in post-hematopoietic cell transplant (HCT) patients with conventional GVHD prophylaxis. However, the value of recipient chimerism increase in patients with post-transplant cyclophosphamide (PTCy) is not clear. We compared PTCy to conventional GVHD prophylaxis (non-PTCy) patients regarding engraftment kinetics and the clinical significance of the 2 chimerism parameters, increasing mixed chimerism (IMC) and degree of recipient chimerism increase at the first event (Δ increase). We studied both total and T-cell-specific chimerism. While leukemia relapse is manifested by an increase in total cell recipient chimerism, an increase in T-cell-specific recipient chimerism may be more impactful in predicting relapse because of the effect of increased T-cell-specific chimerism on the graft-versus-leukemia effect. A total of 220 patients (PTCy: 44, non-PTCy: 176) with AML, MDS, and ALL underwent HCT at our institution from January 2014 to September 2020 and were included in this study (Table). Chimerism was tested at least monthly for the first 3 months, followed by every 3 months up until 1-year post-HCT, and then every 6-12 months thereafter. Short tandem repeat or quantitative PCR were used when percent recipient chimerism was ≥5% and PTCy patients achieved complete donor chimerism (CC) in total cells earlier at a deeper level (>99%) as compared to non-PTCy patients. Deeper total cell CC (>99%) was achieved in 79.5% of PTCy vs. 51% of non-PTCy patients at day 250, while CC (>95%) was achieved in almost 90% of patients in both groups within 100 days (Figure 1A and B). In comparison, the percentage of PTCy patients achieving T-cell-specific CC was significantly higher at day 250 post-HCT: CC (>95%/>99%) was 79.7%/68.4% in PTCy patients vs. 56.1%/37.5% in non-PTCy patients (Figure 1C and D). To evaluate their impact in predicting relapse, IMC was stratified into no IMC, 1 IMC (≥1 nonconsecutive IMC), and 2 IMC (≥2 consecutive IMC), and degree of recipient chimerism increase at the first event (Δ increase) was stratified into Two IMC (total), 1 IMC (T-cell), and 2 IMC (T-cell) groups were associated with shorter DFS in non-PTCy patients but not in PTCy patients (Figure 2). One and 2 IMC groups (both total and T-cell) were associated with relapse risk in non-PTCy patients. Furthermore, 1 IMC (T-cell) in non-PTCy patients showed a strong association in relapse risk (HR 7.0 (95%CI 2.83-17.8) p Δ increase ≥1% (total and T-cell) and Δ increase ≥0.1% (T-cell) were associated with shorter DFS in non-PTCy patients, while only Δ increase ≥1% (T-cell) only showed a trend towards shorter DFS in PTCy patients (Figure 3). The Cox regression model showed Δ increase ≥1% in both total, and T-cell chimerism was associated with relapse risk in non-PTCy patients (HR 6.4 (95%CI 2.9-14.2) p This is one of the most extensive studies investigating engraftment kinetics and the association of total and T-cell recipient chimerism increase to predict leukemia relapse in PTCy and non-PTCy HCT recipients. We found that PTCy HCT recipients achieved deeper engraftment earlier as compared to non-PTCy recipients. In addition, the two chimerism parameters (IMC and Δ increase) are less reliable in predicting relapse in PTCy than non-PTCy recipients. However, other factors, such as disease type, conditioning regimen, and donor HLA disparity, may have affected engraftment kinetics and the significance of chimerism parameters. Further investigations are warranted to elucidate the impact of the engraftment kinetics and recipient chimerism increase to predict relapse, especially in the PTCy setting. Figure 1 Figure 1. Disclosures Rakszawski: SeaGen: Speakers Bureau. Naik: Takeda: Other: Virtual Advisory Board Member ; Sanofi: Other: Virtual Advisory Board Member ; Kite: Other: Virtual Advisory Board Member. Rybka: Spark Therapeutics: Consultancy; Merck: Consultancy. Claxton: Astellas: Other: Clinical Trial; Novartis: Research Funding; Astex: Research Funding; Cyclacel: Research Funding; Daiichi Sankyo: Research Funding; Incyte: Research Funding.

BACKGROUND: Our group recently reported on the results of Blood and Marrow Transplant (BMT) Clinical Trials Network (CTN) 1101 a randomized comparison between double umbilical cord blood (dUCB) and haploidentical bone marrow (haplo) with post-transplant cyclophosphamide (ptCy) in the nonmyeloablative setting that showed similar progression free survival (PFS) between the two treatment groups, but lower non-relapse mortality (NRM) and better of overall survival (OS) in the haplo arm. In this secondary analysis we sought to investigate if transplant center experience with haplo and or cord blood HCT had an impact on outcomes. PATIENTS AND METHODS: All patient randomized in BMT CTN 1101 were included. In order to determine the transplant center experience with either haplo or dUCB we queried the Center for International Blood and Marrow Transplant Research (CIBMTR) for number of transplants with each platform in the year prior to initiation of the study. Centers were then grouped as dUCB center (> 10 dUCB, n=117, 10 centers), Haplo center (>10 haplo and ≤10 dUCB, n=110, 2 centers), and ≤10 haplo and ≤10 dUCB HCTs (other center, n=140, 21 centers). Further analysis considered the alternative cut-off for haplo (> 5 vs ≤ 5) experience, and considered the outcomes based on the donor experience vs. others (e.g. dUCB > 10 vs. ≤ 10; haplo > 5 vs. ≤ 5). RESULTS: The effect of center experience on HCT outcomes shown in Figure, below . After adjusting for age, Karnofsky performance score and, disease risk index we found that there was no difference in outcomes between haplo and dUCB for centers that were experienced with dUCB or had limited to no experience with either dUCB or haplo. In contrast, in centers that were primarily experienced with haplo had better outcomes with this donor type, as compared to dUCB. The higher risk of treatment failure (relapse or death) and overall mortality in dUCB in haplo experienced centers was driven by significantly higher risk of relapse. We then considered the transplant experience with each of the donor types separately. In transplant centers that had performed > 10 dUCB, there were similar outcomes for recipients of both dUCB and haplo. Similarly, centers that had ≤ 5 haplo HCTs had no difference in outcomes between donor types suggesting an overlap with centers that had performed > 10 dUCB HCTs. Overall mortality was higher among dUCB recipients in centers that had performed ≤ 10 dUCB. Notably, the hazard ratio of non-relapse mortality favored haplo in all four donor experience type of transplant center, albeit not statistically significant. CONCLUSION: Except for dUCB recipients in centers with < 10 dUCB/year had worse overall mortality, primarily driven by relapse, the transplant center experience in the year prior to the initiation of BMT CTN 1101 had limited impact on the outcomes of this randomized clinical trial. Figure 1 Figure 1. Disclosures Brunstein: NANT: Research Funding; FATE: Research Funding; GamidaCell: Research Funding; BlueRock: Research Funding; AlloVir: Consultancy. Costa: Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Speakers Bureau; Pfizer: Consultancy, Honoraria; BMS: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria. Cutler: Deciphera: Consultancy; Cimeio: Consultancy; Editas: Consultancy; Kadmon: Consultancy; Pfizer: Consultancy; Mallinckrodt: Consultancy; CareDx: Consultancy; Incyte: Consultancy; Omeros: Consultancy; Syndax: Consultancy; Mesoblast: Consultancy; Jazz: Consultancy. Horowitz: Sobi: Research Funding; Regeneron: Research Funding; Orca Biosystems: Research Funding; Tscan: Research Funding; Xenikos: Research Funding; Miltenyi Biotech: Research Funding; Stemcyte: Research Funding; Medac: Research Funding; Vor Biopharma: Research Funding; Kite/Gilead: Research Funding; Janssen: Research Funding; Pharmacyclics: Research Funding; Kiadis: Research Funding; Seattle Genetics: Research Funding; Mesoblast: Research Funding; GlaxoSmithKline: Research Funding; Sanofi: Research Funding; Pfizer, Inc: Research Funding; Omeros: Research Funding; Magenta: Consultancy, Research Funding; Jazz Pharmaceuticals: Research Funding; Vertex: Research Funding; Genentech: Research Funding; Takeda: Research Funding; Novartis: Research Funding; Shire: Research Funding; Gamida Cell: Research Funding; Daiicho Sankyo: Research Funding; CSL Behring: Research Funding; Chimerix: Research Funding; Bristol-Myers Squibb: Research Funding; bluebird bio: Research Funding; Astellas: Research Funding; Amgen: Research Funding; Allovir: Consultancy; Actinium: Research Funding. Horwitz: Gamida Cell: Research Funding. McGuirk: Novartis: Research Funding; Magenta Therapeutics: Consultancy, Honoraria, Research Funding; EcoR1 Capital: Consultancy; Pluristem Therapeutics: Research Funding; Novartis: Research Funding; Bellicum Pharmaceuticals: Research Funding; Astelllas Pharma: Research Funding; Gamida Cell: Research Funding; Fresenius Biotech: Research Funding; Allovir: Consultancy, Honoraria, Research Funding; Juno Therapeutics: Consultancy, Honoraria, Research Funding; Kite/ Gilead: Consultancy, Honoraria, Other: travel accommodations, expense, Kite a Gilead company, Research Funding, Speakers Bureau. Rezvani: US Department of Justice: Consultancy; Kaleido: Other: One-time scientific advisory board; Nohla Therapeutics: Other: One-time scientific advisory board; Pharmacyclics-Abbvie: Research Funding. Rybka: Spark Therapeutics: Consultancy; Merck: Consultancy. Vasu: Kiadis, Inc.: Research Funding; Boehringer Ingelheim: Other: Travel support; Seattle Genetics: Other: travel support; Omeros, Inc.: Membership on an entity's Board of Directors or advisory committees.

Introduction: Non-myeloablative conditioning regimens enable elderly and younger patients with significant comorbidities to undergo allogenic stem cell transplant (allo SCT). These regimens allow for the benefit of graft-versus-leukemia (GVL) effect with reduced toxicity. A retrospective analysis of 94 patients with acute myeloid leukemia (AML) who received a non-myeloablative transplant with fludarabine (25 mg/m2 days -7 through -3)/cyclophosphamide (1000 mg/m2 days -7 and -6) (Flu/Cy) conditioning was conducted to evaluate patient outcomes. Methods: Ninety-four patients with AML underwent non-myeloablative allo SCT with Flu/Cy conditioning at Penn State Cancer Institute between 2007 and 2015 were retrospectively analyzed. The patients were deemed ineligible for myeloablative or reduced intensity conditioning transplants due to advanced age or significant comorbidities. Most unrelated donor patients (n=69) received tacrolimus/sirolimus/methotrexate as graft-versus-host disease (GVHD) prophylaxis. Overall survival (OS) and disease-free survival (DFS) were assessed with Kaplan-Meier survival curves and log rank tests, and non-relapse mortality (NRM) and relapse rates (RR) were assessed with cumulative incidence of competing events and Gray test. Cox proportional hazard regression with stepwise selection was used for multivariate analysis. Results: Patients with AML underwent Flu/Cy conditioning for allo SCT from either a matched related donor (MRD) (n =16), matched unrelated donor (MUD) (n=54), or mismatched unrelated donor (MMUD) (n=24). Evaluation of AML status immediately prior to allo SCT identified 79 patients in complete remission, 10 patients with non-remission, and 5 patients with primary induction failure. There were 11 patients with hematopoietic cell transplantation specific comorbidity index (HCT-CI): 0, 14 patients with HCT-CI: 1-2, and 69 patients with HCT-CI: ≥3. Post-transplant analysis identified: 48 patients with grade 0, 31 patients with grade I, and 15 patients with grade II-IV acute graft-versus-host disease (aGVHD). Furthermore, 52 patients were without chronic GVHD (cGVHD), 15 experienced limited cGVHD, and 13 experienced extensive cGVHD. One-year OS and DFS were 41.3% (95% CI: 31.3-51%) and 27.7% (95% CI: 18.7-37.4%), respectively. One-year NRM and RR were 12.9% (95% CI: 0.68-21%) and 59.5% (95% CI: 48.2-69.1%). There were no statistically significant differences in NRM between patients with varying comorbidity indices. One-year OS for patients in complete remission versus non-remission prior to transplant was 45.3% versus 20.0% (p Conclusions: The primary endpoint for this retrospective analysis was OS following non-myeloablative allo SCT for AML utilizing Flu/Cy conditioning. Although RR was high (59.5%), this conditioning regimen resulted in rapid stem cell recovery and low NRM. There were no significant differences in NRM between patients with lower (0, or 1-2) and higher (≥3) HCT-CI and patients receiving MRD, MUD or MMUD. This confirms that Flu/Cy conditioning is safe, especially for patients with multiple comorbidities and receiving MMUD. This analysis also identified a significant improvement in OS for patients with grade I as compared to grade II-IV aGVHD. Also, patients with cGVHD showed a significantly reduced RR. Collectively, the improved survival for patients with grade I aGVHD and cGVHD may be associated with a more robust GVL effect. Additionally, patients who achieve a higher chimerism showed a reduced RR. This study highlights the tolerability of Flu/Cy and the importance of balancing GVHD and GVL effects; future studies are needed to evaluate the addition of maintenance therapies to overcome higher RR occurring with this regimen. Disclosures Naik: Celgene: Other: Advisory board. Zheng:Pfizer: Research Funding. Claxton:Daiichi Sankyo Co. and Ambit Biosciences Corp, Astellas Pharma, Novartis Pharmaceuticals, Incyte Corporation, Cyclacel Pharmaceuticals, Inc, Celegene Corporation, Medimmune, Inc, Merck Sharp & Dohme Corp., Gilead Sciences, Inc.: Research Funding.

Treatment for elderly AML patients who are unfit for intensive chemotherapy remains challenging. Induction with hypomethylating agents (HMA) are the most commonly used approach, however the rate of complete remission (CR) is only around 20% and median survival of 7-12 months. Clearly how to improve the clinical outcome in this patient population is an unmet need. Immunotherapy is promising in cancer treatment. A recent study demonstrated that HMA enhanced PD-1 pathway in MDS and AML patients (Yang et al., Leukemia 2014), suggesting a role of combining HMA and immunotherapy in leukemia therapeutics. To optimize this strategy, it is crucial to understand the interaction between HMA and immune response in AML. Here we performed both phenotypic and functional analysis on clinical samples collected from AML patients undergoing treatment of decitabine (DAC), a broadly used HMA. We aim to determine 1) how DAC influences the immune system; and 2) whether the immune status in AML patients predict the response to DAC treatment. Total of 22 peripheral blood samples from 11 AML patients receiving DAC were examined. Samples were collected at the time of prior to and 1-month post DAC treatment. We conducted a comprehensive phenotypic analysis of immune markers characterizing each immune component (T cells, B cells, NK, NKT, monocytes, myeloid-derived suppressor cells, and dendritic cells) and expression patterns of co-stimulatory or inhibitory molecules. In addition, perforin, granzyme B and cytokine release in response to anti-CD3/CD28 stimulation were examined to determine the functional status of T cells. A total of 45 markers separated in 8 overlapped staining panels were tested by flow cytometry. We first assessed the impact of DAC on the immune response in AML. Comparing the paired samples prior to vs. post treatment from the same patients, we observed an increase of the percentage of NK cells, as well as their expression of granzyme B and perforin upon DAC treatment. In contrast, DAC appears to cause CD8 T cell suppression as CD8 T cells from post-DAC samples showed higher PD-1 expression whereas lower IFN-γ production. We next investigated the predictive value of immune status for the response to DAC treatment. Among the 18 evaluable samples, we defined 10 responders (CR/Cri/PR) vs. 8 non-responders (treatment failure) based on the ELN 2017 recommendations. The correlation of immune characteristics to the clinical response was carefully examined. We started with an unsupervised principal component analysis (PCA), which revealed a distinguished pattern between the responders and non-responders (Fig. 1A). This encouraging observation suggests an association of immune signature to clinical outcome. Subsequent analysis demonstrated a major contribution of CD8 T cells to the association. We then focused on the phenotypic and functional analysis of CD8 T cells in responders vs. non-responders. We found a significantly higher percentage of terminal differentiated cells in non-responders compared with that of responders. Importantly, in the perspective of phenotypes, hierarchical clustering on markers of CD8 T cells divided samples into two major clades, 7 of 8 samples (87.5%) were responders on one branch and 7 of 10 samples (70%) were non-responders on the other. Most responders expressed lower frequency of inhibitory receptors and higher frequency of stimulatory receptors, whereas non-responders showed the opposite trend (Fig. 1B). The significant difference of these receptors was validated in paired t test analysis. Functional studies also showed more IFN-γ production in responders. Interestingly the intracellular staining of perforin and granzyme B was higher in non-responders, likely due to exhausted T cells that are unable to release these particles extracellularly. Collectively, our study discovered the vital role of the immune signature in predicting clinical outcome in AML. High functional CD8 T cell status, manifested by more capability of IFN-γ production, enhanced stimulatory molecule and low inhibitory receptor expression, associated with effective clinical response to DAC treatment. In addition, CD8 T cell function was down-regulated upon DAC treatment. Our results provide a strong rationale for integrating immunotherapy into HMA treatment in AML, also highlight the importance of immune signature analysis in the future trial design for this clinical setting. Disclosures No relevant conflicts of interest to declare.

Human herpesvirus 6 activity (HHV-6) was studied in 15 allogeneic and 11 autologous marrow transplantation patients. After transplantation, HHV-6 was isolated from the peripheral blood mononuclear cells of 12 of 26 patients (6 allogeneic and 6 autologous). All isolates were variant B. Eleven of 26 and 12 of 19 patients showed salivary shedding of HHV-6 DNA before and after transplantation, respectively. The antibody titer increased in 7 of 26 patients. Thus, 23 of 26 patients showed evidence of active HHV-6 infection either by virus isolation, salivary shedding, or increases in antibody titers. The fraction of saliva specimens positive in 19 patients was negatively associated with their antibody titers (P= .005). The proportion of cultures positive increased after transplantation (P = .007). Sinusitis was associated with HHV-6 isolation in autologous recipients (P= .002). In allogeneic patients, active human cytomegalovirus infection was associated with HHV-6 isolation (P = .04). No association was observed between HHV-6 infection and GVHD, pneumonia, delay in engraftment, or marrow suppression. Of the 120 clinical events analyzed in 26 patients, HHV-6 was defined as a probable cause of 16 events in 9 patients based on the propinquity of HHV-6 activity and the clinical event plus the absence of other identified causes of the event.

Introduction: High-dose cytarabine consolidation chemotherapy for acute myeloid leukemia (AML) induces profound transient myelosuppression. Thrombocytopenia is a limiting factor in chemotherapy administration for maintaining dose intensity and schedule as thrombocytopenic-related hemorrhage may contribute to significant morbidity and mortality. Therapeutic and prophylactic platelet (plt) transfusions remain the treatment of choice but the benefits typically last only 3-7 days, are expensive, time consuming, and may induce alloimmunization and transmit infection. PrE0901 was a phase I multi-center study to evaluate the safety and toxicity of eltrombopag, an orally bioavailable thrombopoietin (TPO) receptor agonist, for plt recovery in AML patients (pts) receiving consolidation therapy. Methods: The primary objectives were to determine the safety, tolerability, and optimal dosing of eltrombopag while describing the kinetics of plt recovery in AML pts receiving intensive consolidation. Plt recovery was defined as a sustained plt count of ≥ 20 x 109/L following the nadir with no plt transfusions in prior 7 days or a continued upward trend in plt count for at least 2 successive measurements despite no plt transfusions in 48 hours. We used a standard 3+3 design utilizing a novel dose escalation/de-escalation strategy for pts in either first or second complete remission, ≥18 and ≤70 years of age, who had an ECOG performance status of 0-2. Cytarabine was administered at 3 g/m2 (1.5 g/m2 for pts >60 years) IV over 3 hours twice daily on days 1,3,5. Eltrombopag at assigned dose was administered with a first cycle of cytarabine only. Planned eltrombopag dose levels -2, -1, 1, 2, 3, 4, and 5 were 50, 100, 150, 150, 150, 200, and 300 mg, respectively (Table 1). Eltrombopag was to start on days X, X, 3, -1, -5, -5, and -5 relative to day of cytarabine start and levels -2, -1, 1, 2, 3, 4, and 5, respectively, with day X being variable depending on timing of observed dose limiting toxicities (DLTs). The eltrombopag was continued until plt recovery or for up to 35 consecutive days, whichever occurred first. An exploratory objective was to determine if eltrombopag had an effect on TPO and EPO blood concentrations in this setting. Results: Accrual began on July 31, 2012 and the trial closed on January 8, 2016 upon recommendation after an independent Data and Monitoring Committee reviewed a separate trial of eltrombopag therapy in MDS which demonstrated futility. 104 pts were screened. 54 declined participation and 35 were deemed medically ineligible. A total of 15 eligible pts were enrolled; 14 were treated on study with one pt being withdrawn prior to starting treatment due to infection. Three pts were treated at each of dose levels 1-4 and two were treated on dose level 5. No DLTs were observed. Median time to plt recovery of all pts treated on study was 22.5 (range 16-43) days. Pts in cohort 1 dosed with eltrombopag 150 mg daily starting on day 3 of consolidation demonstrated the fastest plt recovery (median =19 days; range 19, 19, 19) compared to cohort 2 who received 150 mg daily starting on day -1 of consolidation and recovered the slowest (median 23 days; range 16, 23, 43). Dose escalation in terms of starting eltrombopag further in advance of chemotherapy exposure as within cohort 3 (150 mg starting day -5) was associated with a median plt recovery of 27 (range 22, 27, 27) days. Eltrombopag dose intensification with cohort 4 at 200 mg daily and cohort 5 at 300 mg daily was associated with median plt recoveries of 24 (range 18, 24, 26) and 23 (range 19, 27) days, respectively. Kinetics of plt recovery for all cohorts are represented in Figure 1 and duration of eltrombopag exposure for each individual patient is represented in Table 2. Conclusions: Endogenous cytokine (TPO and EPO) levels varied inversely with plt and hematocrit values and did not appear to be affected by eltrombopag dose / schedule (details to be provided at ASH Annual Mtg). Unusually high screen fail numbers warrant examination to guide future trial design in the post-remission setting. The addition of eltrombopag to high-dose cytarabine consolidation therapy was well-tolerated and no DLTs were observed. The results for cohort 1 [eltrombopag 150 mg daily starting on day 3 of consolidation] demonstrated the fastest plt recovery. Further investigation is needed to define the optimal role, dose, and schedule of eltrombopag in the treatment of chemotherapy associated myelosuppression. Disclosures Strickland: Alexion Pharmaceuticals: Consultancy; Ambit: Consultancy; Baxalta: Consultancy; Boehringer Ingelheim: Consultancy, Research Funding; CTI Biopharma: Consultancy; Daiichi Sankyo: Consultancy; Sunesis Pharmaceuticals: Consultancy, Research Funding; Abbvie: Research Funding; Astellas Pharma: Research Funding; Celator: Research Funding; Cyclacel: Research Funding; GlaxoSmithKline: Research Funding; Karyopharm Therapeutica: Research Funding; Sanofi: Research Funding.

Background: Chronic GVHD contributes to morbidity and mortality after allogeneic transplantation. Several phase 2 and 3 open label studies suggested that ATLG (formerly referred to as ATG-F) reduces cGVHD without impacting relapse or survival. This report describes the first prospective randomized double blind phase 3 trial to assess the effect of ATLG (Neovii) when added to tacrolimus / methotrexate prophylaxis on cGVHD free survival. Patients and Methods: This study was conducted at 27 sites in the United States and Australia. 260 patients were randomized (132 placebo, 128 ATLG). 6 patients who were randomized never received ATLG/placebo (4 placebo and 2 ATLG). Data presented include the 128 placebo and 126 ATLG patients who underwent treatment and transplant. Patients were ages 18-65 years with a diagnosis of acute myeloid (AML, 64%) or lymphoblastic (ALL, 21%) leukemia in first or subsequent complete remission or myelodysplastic syndrome (MDS, 15%) with less than 10% marrow blasts. Median age was 48 years (18-65) with 55% males. All patients received 8/8 HLA (A, B, C, DR) allele matched unrelated products (80% mobilized peripheral blood, 20% bone marrow). Myeloablative conditioning was with cyclophosphamide and total body irradiation (Cy/TBI, 27%), busulfan and cyclophosphamide (Bu/Cy, 33%), or busulfan and fludarabine (Bu/Flu, 40%). All patients received tacrolimus starting on Day -1 and standard mtx on days 1, 3, 6, and 11 for GVHD prophylaxis. Patients received ATLG or placebo on Days -3, -2, -1 at an ATLG dose of 20 mg/kg per day (60 mg/kg total). The primary endpoint of the study was moderate/severe chronic GVHD free survival. cGVHD was scored by the investigator and then confirmed or overturned by an independent adjudication committee. Secondary endpoints included engraftment, acute GVHD , moderate/severe cGVHD, non-relapse mortality, GVHD and relapse free survival (GRFS), progression free (PFS) and overall survival (OS). The impact of ATLG on immune reconstitution was assessed in 91 patients. Results: Treatment arms were balanced with respect to age, diagnosis, remission status, cytogenetics, graft source (PB or BM), CMV serostatus and conditioning regimen. Median follow up of survivors was 745 days (61, 1425). Regarding the primary endpoint, there was no difference in 2 year moderate/severe cGVHD free survival between ATLG and placebo (48 vs 44%, p = 0.57), nor was there a difference in GRFS (Table 1). Neutrophil engraftment at Day 30 was less in the ATLG arm (85% vs 95%, p=0.00001). Grade 2 or higher infusion reactions were higher in the ATLG arm (16% vs 2.3%, p=0.0001). Reactivation of CMV was similar (27% vs 31%, p=0.58). The Day 180 cumulative incidence of grades 2-4 acute GVHD was lower in the ATLG arm (23 vs 40%, p = 0.003) as was the 2-year cumulative incidence of moderate/severe cGVHD (12 vs 33%, p = 0.000006). However, both 2-year OS and PFS were lower in ATLG treated patients (58 v 76% and 47 vs 67%, respectively) due in part to a higher incidence of relapse (32 vs 19%, p=0.068). Multivariable models confirmed that ATLG was associated with inferior OS, HR 1.85 (1.1-2.9, p=.0075) and PFS, HR 1.63 (1.1-2.41, p=0.015). We then conducted an unplanned post-hoc analysis and discovered a striking influence of conditioning regimen on outcomes. There were no differences in OS or PFS between ATLG and placebo arms in patients receiving Bu/Cy or Bu/Flu but a dramatic difference in patients receiving Cy/TBI conditioning (OS, 88% vs 48% p =0.006 and PFS, 75 vs 29%, p=0.007 in placebo and ATLG arms, respectively). 91 patients (44 ATLG, 47 placebo) participated in the immune reconstitution study. ATLG treatment was associated with lower CD3, CD4, and CD8 counts at Days 30, 100, and 360, respectively. In turn lower CD3, CD4, and CD8 counts assessed as time dependent variables were all associated with inferior OS and PFS as well as higher NRM (data not shown). Conclusion: In this first ever prospective, randomized, double blind trial of ATLG added to tacrolimus /methotrexate in recipients of matched unrelated donor grafts after myeloablative conditioning, there was no significant difference in 2 year moderate/severe cGVHD free survival or GRFS. ATLG did significantly reduce grades 2-4 acute and moderate/severe chronic GVHD. However, overall survival was higher in the placebo arm, driven mainly by patients who received Cy/TBI conditioning. Further analyses are needed to understand the proper role for ATLG in HCT. Disclosures Soiffer: Juno: Membership on an entity's Board of Directors or advisory committees; Kiadis: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Porter:Genentech: Employment; Novartis: Patents & Royalties, Research Funding. Jagasia:Therakos: Consultancy. Szer:Alnylam: Honoraria, Membership on an entity's Board of Directors or advisory committees; Ra Pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees; Alexion Pharmaceuticals, Inc.: Honoraria, Membership on an entity's Board of Directors or advisory committees. Ritz:Kiadis: Membership on an entity's Board of Directors or advisory committees. Glavin:Neovii Biotech: Employment. Chen:Incyte Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding.

The ECOG-ACRIN Cancer Research Group Led Trial, E2902, was a randomized phase III North American Leukemia Intergroup trial of the Farnesyl Transferase Inhibitor , R115777(Tipifarnib), as maintenance therapy for acute myeloid leukemia (AML). Patients (pts) with AML in remission after requiring salvage therapy (primary induction failure or second or subsequent remission) or over the age of 60 in first remission were eligible. Pts were eligible if they were in a complete remission (CR) or complete remission without platelet recovery (CRp) as confirmed by bone marrow examination within 2 weeks prior to randomization. Consolidation or post remission therapy prior to enrollment was allowed but not required. Pts who had received an allogeneic transplant in this remission were ineligible. Adequate blood counts (absolute neutrophil count >= 1000/mm3 and platelet count >=50,000/mm3), and normal renal, and hepatic function were required within 2 weeks of randomization. Pts were randomized to either receive tipifarnib twice daily (BID) or to observation. Pts were stratified by remission ( CR1 vs > CR1) and whether or not they received consolidation therapy in the current remission. The main objective of this study was to compare disease free survival(DFS) in the two groups. Between August 2004 and December 2009, 144 pts were accrued to the study. The median age of the pts was 69 (range 28-86). Seventy-three pts (51%) were male and 135 pts (94%) were white. The majority of pts enrolled on the study (70%) were in first CR, and had post remission chemotherapy (56%) prior to randomization. Seventy-three pts were enrolled onto the treatment arm (Arm A) and 71 pts were enrolled onto the observation arm (Arm B). When the study was initially opened, pts on Arm A were treated with tipifarnib at a dose of 400 mg BID with dose reductions and interruptions defined per protocol for toxicity. After the first planned interim analysis, based on toxicity data, the ECOG Data Monitoring Committee recommended that the starting dose be decreased to 300 mg BID. While non-hematologic toxicity was acceptable, significant hematologic toxicity was seen in pts treated at an initial dose of either 400 mg or 300 mg BID. Of note, hematologic toxicity was also seen on the observation arm although less frequently than with both treatment doses. The primary endpoint of the study was analysis of DFS on an intent to treat basis. The median DFS for arms A and B are 8.87 months and 5.26 months respectively ( p=0.058, HR 0.760). When restricted to eligible patients only(n=134 ), the DFS for arms A and B are 10.81 vs 5.26 months, respectively ( p=0.019, HR 0.690). An unplanned subgroup analysis was performed by gender. The median DFS for male pts (n=73) is 5.36 vs 5.91 months for arms A and B respectively (p=0.868, HR 1.320) and 12.09 vs 3.91 months for female pts (n=71)(p=0.0002, HR=0.408) In a multivariate Cox proportional hazards model to adjust for baseline clinical variables, there is a significant interaction between treatment and gender. (Table 1) Similar results were noted for OS (Figure 1). ECOG ACRIN Trial E2902 evaluated the potential role of Tipifarnib ( R115777) in patients with AML in remission with a high risk of relapse. While the primary endpoint for improved DFS was not reached when evaluating all randomized pts, when restricted to eligible patients only, there is a statistically significant improvement in DFS seen. Moreover, an unplanned subgroup analysis by gender demonstrates an improvement in DFS and OS for females who were enrolled on the study which persists on multivariate analysis. Possible explanations include the use of flat dosing rather than BSA based dosing on this study. However futher evaluation of patient and disease characteristics, dosing and toxicity profiles of responders and nonresponders is needed. Given what appears to be a potentially clinically relevant benefit, further evaluation of this agent is warranted. Table 1. Multivariate Cox Proportional Hazards Model for DFS: All Randomized Patients Hazard Ratio (95% CI) P value Arm B vs A 2.559(1.547,4.236) 0.00025 Male vs Female 2.005(1.228,3.274) 0.00544 CR1 vs >CR1 0.447 (0.305,0.656) 0.00004 Figure 1. (A) DFS (B) OS in Female Patients Figure 1. (A) DFS (B) OS in Female Patients Disclosures Rowe: BioSight Ltd.: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy; BioLineRx Ltd.: Consultancy. Larson:Astellas: Consultancy, Research Funding.

Abstract 2054 Background: No clear consensus exists for the setting of supportive care after induction chemotherapy given for newly diagnosed acute myeloid leukemia (AML). While many centers provide care exclusively via in-patient settings, others including the Penn State Hershey Cancer Institute select suitable patients for discharge following chemotherapy and provide supportive care in out-patient infusion centers. Our single center practice offers 7 day a week transfusion and antibiotic support from skilled subspecialty nurses and midlevel practitioners. For ambulatory, afebrile AML patients with appropriate caregivers and social support allowing ∼q48 hour visits we encourage early discharge after administration of chemotherapy but before recovery from marrow aplasia. Patients are then readmitted if febrile or if other circumstances mandate hospitalization. This study presents results of this approach. Methods: We analyzed results of management including the option of early discharge in a series of 347 consecutively treated newly diagnosed adult AML patients receiving cytarabine based, aplasia inducing chemotherapy between 2003 and 2010. 334 patients received 7 days of infusional cytarabine with 3 days of anthracycline or anthracedione (“7+3” – in a few cases with additional agents), while the other 13 received bolus high or intermediate dose cytarabine with other agents. Patients were ages 18–85 years (median age 60). All received induction chemotherapy in the hospital. We classified cases into those discharged prior to recovery of neutrophils (ANC) to >500/ul or with ANC>500 but before the ANC nadir was reached (“Early” discharges), those kept in hospital throughout the period of ANC Results: Early discharge (after chemotherapy but prior to recovery of ANC>500) was employed in 259/347 patients of median age 60 years (range 18–85). They were outpatients for a median of 13 (range 1–23 days), of the initial 28 days from the start of chemotherapy (defined as day 0). 185/259 required readmission for sepsis or other complications prior to recovery of neutrophils. 234/259 recovered to ANC>500 at days 15–132. OS for this early discharge group was 96.1%, 90.0%, and 59.5% at 28, 60, and 365 days respectively. We analyzed predictive factors for survival at day 60 (OS60) in this group. While pretreatment WBC, platelets and albumin values were not related to OS60, greater age and unmarried status correlated with death prior to day 60. Mean age for those with survival at D60 was 55.89 and for those dying by D60 was 69.70 (95%CI 7.909 to 19.72 for the difference between means and p500, all surviving to day 60. Thirty patients of 347 died during the first hospitalization. Conclusions: In this retrospective review, early discharge following AML induction chemotherapy was generally safe and was offered to 259 of 347 patients treated. Risk factors for death at day 60 in this group included advanced age and unmarried status. Prospective studies will be needed to confirm these data. This work has implications for safe and cost effective management of AML. Additional analysis is underway. Disclosures: No relevant conflicts of interest to declare.

Abstract 676 Although maintenance therapy has been shown to be of value in Acute Lymphoid Leukemia, its role in non M3 Acute Myeloid Leukemia (AML) has never been proven. Studies have been limited by issues related to efficacy as well as toxicity. The Eastern Cooperative Oncology Group (ECOG) trial, E2902, was a randomized phase III intergroup trial of the Farnesyl Transferase Inhibitor, R115777(tipifarnib), as maintenance therapy for AML. Patients(pts) with AML in remission after requiring salvage therapy or over age 60 in first remission were eligible. A confirmatory bone marrow exam prior to randomization was required to demonstrate a complete remission (CR) or morphologic remission(MR). Absolute neutrophil count >1000/mm3, platelet count >=50,000/mm3, normal renal, and hepatic function were required. Consolidation or post remission therapy prior to enrollment was allowed but not required. Pts who had received an allogeneic transplant in this remission were ineligible. Pts were randomized to either receive tipifarnib twice daily (BID) or to observation. The main objective of the study was to compare disease free survival (DFS) in the two groups. The study was designed with 84% power to detect a 76% relative increase in the median DFS from 3.4 months to 6 months (mo). The final analysis was to take place when 111 events had taken place. Between August 2004 and December 2009, 144 pts were accrued to the study. The median age of the pts is 70 (range 28–86). The majority of pts enrolled on the study (67%) were in first CR. Seventy three pts were enrolled onto the treatment arm and 71 pts were enrolled onto the observation arm. When the study initially opened, tipifarnib was given at a dose of 400 mg BID with dose reductions and interruptions as per protocol for toxicity. Based on the first interim analysis, toxicity data, the starting dose was decreased to 300 mg BID. Significant hematologic toxicity was seen in patients at both 300 and 400 mg. The majority of patients experienced >=grade 3 neutropenia or thrombocytopenia. There was 1 episode of febrile neutropenia. Non-hematologic toxicities were minimal. At the time of 110 events (90 relapses and 100 deaths), the final analysis of the study was conducted. The relapse rate was 60.3% on tipifarnib vs 64.8% for observation. Median DFS and 10 and 12 mo DFS and overall survival (OS) are documented in Table 1. Kaplan Meier curves for DFS and OS are presented. As the difference in median DFS is not considered significant (9.3 vs 5.8 mo, log rank p value 0.21), in July 2011, pts and physicians were informed of the lack of evidence of benefit so they could decide if they wished to continue drug. However an unplanned analysis of the data demonstrates a statistically significant improvement in OS at 10 months in pts who received tipifarnib. (70% vs 48%, p=0.05). While the benefit is subsequently lost, given a median survival measured in months, an increase in the number of pts alive and/or without disease at 10–12 mo is of value, particularly in the absence of noteworthy toxicity. Future studies are needed to better determine the role of maintenance therapy in pts with AML. Tipifarnib Observation Median DFS (months) 9.3 (95% CI:5.7, 13.3) 5.8 (95% CI: 3.7, 8.8) p=0.21 OS rate at 10 mo 70% (95% CI: 58%, 79%) 48% (95% CI: 36%, 60%) p=0.05 OS rate at 12 mo 59% (95% CI: 47%, 70%) 44% (95% CI: 32%, 55%) p=0.07 DFS rate at 10 mo 47% (95% CI: 36%, 59%) 32% (95% CI: 21%, 43%) p=0.07 DFS rate at 12 mo 39% (95% CI: 28%, 50%) 30% (95% CI: 20%, 41%) p=0.26 Disclosures: Larson: Novartis: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Research Funding; Pfizer: Consultancy; Ariad: Consultancy, Research Funding.

Abstract 3315 The Eastern Cooperative Oncology Group (ECOG) trial, E2902, was a randomized phase III intergroup trial of the Farnesyl Transferase Inhibitor, R115777(Tipifarnib), as maintenance therapy for acute myeloid leukemia (AML). Patients (pts) with AML in remission after requiring salvage therapy (primary induction failure or second or subsequent remission) or over the age of 60 in first remission were eligible. A confirmatory bone marrow exam was required within 2 weeks prior to randomization. Pts were eligible if they were in a complete remission (CR) or morphologic remission (MR). Consolidation or post remission therapy prior to enrollment was allowed but not required. Pts who had received an allogeneic transplant in this remission were ineligible. Adequate blood counts (absolute neutrophil count >= 1000/mm3 and platelet count >=50,000/mm3), and normal renal, and hepatic function were required within 2 weeks of randomization. Pts were randomized to either receive tipifarnib twice daily (BID) or to observation. The main objective of this study was to compare disease free survival in the two groups. Although the study has completed accrual, an insufficient number of events have been recorded at this point to allow for evaluation of the survival data. However, toxicity data are now available. Between August 2004 and December 2009, 144 pts were accrued to the study. The median age of the pts is 70 (range 28–86). Seventy-three pts (51%) were male and 135 pts (94%) were white. Seventy-three pts were enrolled onto the treatment arm (Arm A) and 71 pts were enrolled onto the observation arm (Arm B). When the study was initially opened, pts on Arm A were treated with tipifarnib at a dose of 400 mg BID with dose reductions and interruptions defined per protocol for toxicity. After the first planned interim analysis, based on toxicity data, the ECOG Data Monitoring Committee recommended that the starting dose be decreased to 300 mg BID. The majority of pts enrolled on the study were in first CR (CR1) (Table 2). Among the 30 pts treated with the initial 400 mg BID dose, 23 pts (77%) had their dose held or reduced to a lower dose in the subsequent treatment cycles. For the 41 pts whose initial dose was 300 mg BID, 61% required either dose modification (n=19) or discontinued (n=6) due to toxicity. Table 1: Baseline characteristics Arm A 400 mg BID n=31 Arm A 300 mg BID n=42 Arm B Observation n=71 CR1 16 (52%) 34 (81%) 47 (66%) >CR1 10 (32%) 8 (19%) 16 (23%) Unknown 5 (16%) 16 (11%) Table 2: Toxicity Toxicity Type Arm A 400 mg n=31 Arm A 300 mg n=41 Arm B Observation n=69 Grade (n) Grade (n) Grade (n) 3 4 3 4 3 4 Hemoglobin 1 1 6 1 1 2 Leukocytes 2 4 16 4 3 Neutrophils 5 8 3 7 1 Platelets 4 10 11 11 1 5 Cardiac-ischemia 1 Fatigue 1 Diarrhea 1 Nausea 1 Febrile neutropenia 1 1 Infection w/gr 3-4 neutrophils (ANC) 1 Infection Gr0-2 ANC 1 1 3 GGT 1 Hypokalemia 1 Confusion 1 Agitation 1 Neuropathy-sensory 1 Back pain 1 Worst degree Non Hematologic 4 2 9 1 1 While non-hematologic toxicity was acceptable, significant hematologic toxicity was seen in pts treated at an initial dose of either 400 mg or 300 mg BID (Table 2). Of note, hematologic toxicity was also seen on the observation arm although less frequently than with both treatment doses. Non-hematologic toxicity was much less frequent overall and there were no significant non-hematologic toxicities in the observation arm. Reduction of the initial dose did not ameliorate either the hematologic or non-hematologic toxicity seen on the treatment arms. There was however no fatal toxicity at either dose level. Results of the randomization with respect to efficacy remain essential to determining the utility of this agent as maintenance therapy in AML. Disclosures: No relevant conflicts of interest to declare.

Abstract 4353 Currrent therapy for acute myelogenous leukemia depends on the activity of cytosine arabinoside (ara-C). The development of regimens without this agent would potentially provide non-crossresistant treatment options for these disorders. Clofarabine, a novel agent showing significant single agent activity in AML, provides a platform for potentially effective treatment independent of ara-C. We treated 10 patients ages 30–67 (median 51) with relapsed or refractory AML with a phase I dose finding protocol employing a three drug combination based on clofarabine. The objectives were to define a maximally tolerated and recommended phase 2 dose and identify early phase 2 activity. Seven patients (70%) were refractory to 1 or 2 treatment regimens immediately prior to enrollment, the other 3 pts (30%) were relapsed following a remission. All patients had relapsed following or were refractory to standard 7+3 chemotherapy and 7/10 had received intermediate or high dose cytarabine within We conclude that the clofarabine, etoposide and mitoxantrone combination has acceptable toxicity and is an active regimen for significantly pretreated acute myelogenous leukemia. The total response rate compares favorably with other AML salvage regimens. As there has been delayed myeloid recovery at higher doses, we are pursuing DL1. The activity of this regimen is potentially non-crossresistant with ara-C, therefore larger studies are justified. Currently, patients are enrolling in an expanded cohort at the recommend phase 2 dose. Disclosures: Claxton: Genzyme: Research Funding. Off Label Use: Clofarabine for AML therapy.

Abstract 4301 Introduction Donor lymphocyte infusions (DLI) can reverse relapse of hematologic malignancy following allogeneic hematopoietic stem cell transplant (HSCT) in some cases. G-CSF is used to mobilize progenitor cells for transplantation and at our center excess cells have been cryopreserved and subsequently used as DLIs. Little is known regarding the effectiveness of G-CSF mobilized cells as DLIs in the treatment of hematological malignancies. We conducted a retrospective study comparing the overall survival in patients treated with G-CSF mobilized vs. conventional DLI for hematological malignancies. Patients and Methods After IRB approval, we conducted a retrospective chart review of 67 patients who received DLI treatment of management of hematological malignancies. Results Mean age was 48.5 (range 2-78). 41 (62%) patients had AML and 26 (38%) had other hematological malignancies. Patients received 1-4 DLIs each; median was 1 DLI per patient. Median no. of CD3+ cells infused was 107/kg body weight (range 1- 265). 17 (25%) patients received a total of 32 G-CSF mobilized DLIs. 50 (75%) patients received 77 conventional DLI. 20 (29%) patients were treated with immunosuppressive agents at the time of DLI and 49 (73%) received chemotherapy in the 90 days prior to DLI. DLIs were administered for relapse or residual disease post-transplant in 62 patients. 5 patients received 7 DLIs because of poor engraftment. In total 38(56%) patients have died. Death was malignant disease related in 31/38(82%) patients, and caused by graft versus host disease (GVHD) in 5/38 (13%). GVHD deaths were 2/17 in the G-CSF and 3/50 in the conventional group (NS). Median survival after DLI was 213 days for the 67 patients and was similar for GCSF and conventional groups. 19/67 patients survived more than 1 year from the initial DLI. Death and GVHD were not predicted by diagnosis, donor type (related of unrelated), use of immunosuppressives at the time and DLI or number of infused donor CD3 cells. Time to first evidence of GVHD was similar between the two groups (p=0.35). Kaplan-Meier estimates of survival suggested that G-CSF mobilized DLI, while not statistically different from conventional DLI, showed a trend towards a survival advantage (p=0.08). This analysis is shown in the figure below. Conclusion In this series of poor prognosis hematological malignancies, DLI was clearly lifesaving in a number of patients. G-CSF mobilized DLI appears to be at least as effective as conventional DLI for the treatment of patients relapsing after allogeneic blood stem cell transplantation. Disclosures: No relevant conflicts of interest to declare.

Abstract 1394 Poster Board I-416 Background: Leukemia is the fifth most common cause of cancer death in men and seventh most common cause in women in the US. Since the advent of multi-drug chemotherapy, studies have shown improvement in survival for specific age groups. However, there have been few studies showing the impact of evolving therapies on survival for the total burden of leukemia patients. We assessed survival for an aggregate population of all patients presenting with leukemia to a regional tertiary university hospital over the past 3 decades. Goal: To assess the magnitude of improvement in survival for patients with leukemia over the past 3 decades. Methods: We analyzed data from the Penn State Hershey Medical Center Cancer Registry, selecting all cases diagnosed with leukemia by ICD-0-3 codes, excluding chronic lymphocytic leukemia, from Jan 1st 1976 to Dec 31st 2006. Five and ten year (yr) absolute survival rates during five time periods [group (gp) 1: 1976-1980, gp 2: 1981-1985, gp 3: 1986-1990, gp 4: 1996-2000, gp 5: 2001-2006] were obtained using conventional period analysis (PA). In addition, a period Cox Proportional Model (CPH) was fit to the data, allowing for survival risk estimates of 5 yr survival, statistical testing of time periods, and adjustments for age at diagnosis. SAS v 9.1 was used to obtain estimates, with Brenner's PERIOD macro used for PA and PHREG used for CPH. Results: Of 1892 patients, chronic myeloid leukemia (CML) accounted for 11%, acute myeloid leukemia (AML) 52% and acute lymphoblastic leukemia (ALL) 37%. Median age was 44 yr and mean was 40 yr with a standard deviation (SD) of 27.2 yr. Median follow up was 1.6 yr and mean was 3.9 yr with SD 5.1 yr. Approximately 13% (N=249) survived beyond 10 yr. CPH adjusted for age demonstrated an improvement in 5 yr survival among all patients with leukemia of 16%, Hazard Ratio (HR)=1.57, p=0.0002, and 16% in 10 yr survival, HR=1.6, p= 0.0001, between gp 5 and gp 1. Consistent improvements in age adjusted 5 yr survival were detected for CML (24%, HR=2.06, p=0.124), AML (17%, HR=1.53, p Conclusion: Our analysis shows that there is a significant improvement of 16% in overall five and ten year survival rates in all leukemia patients over the last 30 years after adjusting for age at diagnosis. Subgroup analysis shows comparable improvements among the three diagnostic groups. Disclosures: No relevant conflicts of interest to declare.

Abstract 4329 The use of sirolimus (rapamycin) as an immunosuppressive agent after allogeneic hematopoietic transplantation is appealing given its antitumor and tolerance-inducing properties. Its safety and efficacy have been studied but are not completely understood in this patient population. We have compared GVHD prophylaxis with sirolimus together with early withdrawal of concomitant tacrolimus to standard tacrolimus in 49 patients receiving non-myeloablative transplant from matched related donors. All patients received identical conditioning with Cyclophosphamide 1g/m2 days –7 and –6 and Fludarabine 25mg/m2 days –7 through –3. Twenty-three patients received standard GVHD prophylaxis with methotrexate and tacrolimus. Twenty-six patients received methotrexate, sirolimus, with tacrolimus tapering over 15 days beginning day 20 or 30. Overall survival (OS) was similar in sirolimus and no sirolimus groups (median 526 vs 723 days, p=0.77). Similarly progression-free survival (PFS) was comparable (median 300 vs 382days p=0.78). Full chimerism was achieved in 73% patients received sirolimus vs. 58%patients received no sirolimus by day 100 (p=0.46). Chimerism was similar in the two groups at all time points examined. Toxicities including microangiopathy (MA), hypertriglyceremia and nephrotoxicity were analyzed. In patients receiving sirolimus MA developed in 2/26(8%) vs. in 1/23(4%) patients receiving no sirolimus (p=0.28). Creatinine >3mg/dl was seen in 6/26 (23%) patients receiving sirolimus vs. 6/23 (26%) patients receiving no sirolimus (p=0.47). In contrast the incidence of hypertriglyceremia (>500mg/dl) was significantly higher in the sirolimus group (10/26, 38% vs 2/23, 9% p Disclosures: Off Label Use: Sirolimus for GVHD prophyllaxis.

Abstract 4527 Background The incidence of lymphoma has doubled in the past 3 decades in the US and most western countries. Since the advent of multi-drug chemotherapy, studies have shown improvement in survival in specific diagnostic groups such as diffuse large B-cell lymphomas. However, there have been few studies showing the impact of evolving therapies on survival for the total burden of lymphoma patients. We assessed survival for an aggregate population of all patients presenting with lymphoma to a regional tertiary university hospital over the past 3 decades. Goal To assess the magnitude of improvement in survival for patients with lymphoma over the past 3 decades. Methods We analyzed data from the Penn State Hershey Medical Center Cancer Registry, selecting all cases diagnosed with lymphoma by ICD-0-3 codes from Jan 1st 1976 to Dec 31st 2006. Five and ten year (yr) absolute survival rates during five time periods [group (gp) 1: 1976-1980, gp 2: 1981-1985, gp 3: 1986-1990, gp 4: 1996-2000, gp 5: 2001-2006] were obtained by using conventional period analysis (PA). In addition, a period Cox Proportional Model (CPH) was fit to the data, allowing for survival risk estimates of 5 yr survival, statistical testing of time periods, and adjustments for age at diagnosis. SAS v 9.1 was used to obtain estimates, with Brenner's PERIOD macro used for PA and PHREG used for CPH. Results Of 2843 patients, Hodgkin's lymphoma accounted for 17%, high grade lymphoma 4%, intermediate grade lymphoma 29%, low grade lymphoma 17%, cutaneous T-cell lymphoma 6%, chronic lymphocytic leukemia and small lymphocytic lymphoma (CLL/SLL) 13%, malignant lymphoma not otherwise specified (NOS) 14%. Median age was 56 yr and mean was 52 yr with a standard deviation (SD) of 20.9 yr. Median follow up was 4 yr and mean was 6 yr with SD 6.5 yr. Approximately 25% (N=700) survived beyond 10 yr. CPH adjusted for age demonstrated a 5 yr improvement among all lymphomas of 8%, Hazard Ratio (HR)=1.31, 95%, p=0.0192, between gp 5 and gp 1. Consistent improvements in 5 yr survival were detected for intermediate grade lymphoma (15%, HR=1.5, p=0.0219), high grade lymphoma (40%, HR=12.83, p Conclusion There has been a significant improvement of 8% in overall 5 yr survival in lymphoma patients over the past 3 decades after adjusting for age. There was an improvement in survival in both intermediate and high grade groups. There was a trend towards declining survival in cutaneous T cell lymphoma. This could be attributed to diagnostic drift with changing classification and to the fewer number of cases diagnosed in the earlier years as compared to later years. Disclosures: No relevant conflicts of interest to declare.

Abstract 1212 Poster Board I-234 Background: The use of sirolimus (rapamycin) as primary immunosuppression for allogeneic blood and marrow transplantation is logical given its favorable anti-tumor and tolerance inducing properties. Methods: After IRB approval, we analysed long term survival and predictive correlates in 92 patients receiving sirolimus based non-ablative alternative donor hematopoietic transplantation for hematological malignancies. All received conditioning with a purine nucleotide and cyclophosphamide 1mg/m2 (d-7, -6), 5mg/m2 methotrexate days 1, 3, 6 and combination sirolimus and tacrolimus each dosed at 6-10 ng/ml levels. Where feasible tacrolimus was discontinued as early as day 50, but sirolimus was continued until at least 9 months unless discontinued for toxicity or relapse. Median age was 57 years (range 23-74). Diagnoses were ALL – 4, AML – 44, CLL – 7, CML – 4, HD – 3, MDS – 4, MM – 2, MPD – 4, NHL – 19, AA-1. Only 32/92 patients were in complete remission (CR) at the time of transplant and only 16 in CR1. Median number of prior chemotherapy regimens was 3 (0-7). CIBMTR risk scores for outcome were: high in 43, intermediate in 28, and low in 20. 11 patients had received prior autologous transplantation (12%). Donors were unrelated (URD) in 80 (87%) patients and 5/6 antigen matched related in 12 (13%). 57 of 80 URD recipients were transplanted with cells matched at HLA A,B,C and DRB1, while the other 23 received cells mismatched at least 1 locus. 86/92 patients received transplants of G-CSF mobilized blood cells, the other 6/92 received bone marrow (all URD). Hospital discharge was generally day 1 post transplant and many engrafted as out patients. Results: Patients were hospitalized a median of only 9 of the initial 100 days post transplant (range 1-66 days). Median follow-up of the 39 surviving patients was 1025 days (214-2414) from transplantation. Primary graft failure (< 10% donor engraftment in survivors at day 30) occurred in 8/92 patients, and secondary graft failure developed in 3/92. In 44/92 (47.8%) tacrolimus was discontinued prior to day 100. Graft versus host disease (GVHD) developed by day 100 in 45/85 patients followed at least 100 days. Median overall survival (OS) was 480 days. OS for AML (44 patients) and NHL(19) +CLL(7) patients is shown in the figure below. Of pre-transplant features, only stage (CR vs other) predicted for OS (p=0.01). Donor chimerism at 100 days was also predictive for OS (HR=0.33, p=0.02). Increased chimerism was correlated with HLA matched grafts (p=0.02) and with increased numbers of infused donor CD34+ve cells (p=0.04). Treatment related mortality was 9/92 (9.8%) at 100 days and 18/85 (21%) at 1 year. Conclusions: Sirolimus treatment with early discontinuation of tacrolimus provides effective GVHD prophylaxis and acceptable long-term survival in a group of older, poor prognosis patients receiving non-ablative allogeneic transplants from alternative donors for hematological malignancies. Measures to further improve day 100 donor chimerism, including improved HLA matching and higher infused numbers of CD34 +ve cells, may yield further improvements. Disclosures: No relevant conflicts of interest to declare.

Autologous peripheral blood stem cell transplantation (ASCT) has been shown to improve survival in patients with multiple myeloma (MM). High-dose melphalan is considered the current standard of care among the preparative regimens used in ASCT for MM patients. We report the results of ASCT in 79 consecutive MM patients using a conditioning regimen with busulfan and cyclophosphamide (Bu/Cy), given as single ASCT and without maintenance therapy. Peripheral blood stem cells were mobilized with cyclophosphamide 5,000 mg/m2 IV + etoposide 1,000 mg/m2 IV, followed by granulocyte colony stimulating factor (G-CSF) 5 mg/Kg/day until the end of stem cell collection. A median of 41.1 × 106 CD34+ cells/Kg (range, 2.1–139.7 × 106) of ideal body weight were mobilized. The conditioning regimen consisted of busulfan 1 mg/Kg PO or 0.8 mg/Kg IV every 6 hours x 16 doses (days -7 to -3), and cyclophosphamide 60 mg/Kg/day IV for 2 days (days -3 to -2). Patients achieved neutrophil engraftment (absolute neutrophil count >500/μL) at a median of +13 days (range, +6 to +21 days), and platelet engraftment (platelets >20,000/μL unsupported by transfusion) at a median of 14 days (range, +11 to +24). Using a transfusion threshold of hemoglobin

We have explored the immunosuppressive agent Sirolimus for immunoprophyllaxis after allogeneic hematopoietic transplant in order to exploit its favorable immunotolerance and antineoplastic properties. Where possible, co-administered tacrolimus has been tapered early so as to minimize its restraint of graft versus tumor activity. Between May 2001 and February 2007, 68 patients with matched unrelated or 5/6 antigen-matched related donors received non-ablative hematopoietic cell transplantation. Conditioning consisted of fludarabine 25mg/m2 (d-7, -6, -5, -4, -3) and cyclophosphamide 1mg/m2 (d-7, -6) followed by 5mg/m2 methotrexate days 1, 3, 6 and combination sirolimus and tacrolimus each dosed at 6–10 ng/ml levels. Median age was 55.2 (range 23.3 to 72.2). Disease diagnoses were ALL - 4, AML - 30, CLL - 7, CML - 3, HD - 1, MDS - 3, MM - 2, MPD - 4, NHL - 14. Only 22/68 patients were in remission (CR1 or CR>1) at transplant. 62/67 patients (5/6 BM and 57/61 PBSC) engrafted stably with donor cells by day 30. Donor blood chimerism was >90 percent in 35/58 by day 100 and was correlated with CD34 cells infused (R=0.263, p=0.033), but not degree of HLA match. In 19/47 patients without GVHD by day 30, tacrolimus was tapered and stopped between days 40 and 100. Sirolimus was continued in the absence of a contraindication for 8 months at least. In 6/19 patients GVHD developed within 2 months of discontinuation of tacrolimus. 2/6 patients developed grade ≥3 GVHD, and in 1/6 GVHD was the cause of death. In 4/6 grade 1–2 GVHD was controlled with steroids and/or reinstitution of tacrolimus. Toxicity was manageable. Post transplant creatinine levels >3.0mg/dl were noted at least briefly in 16/68 patients. Only 4 patients required dialysis. Tacrolimus was discontinued because of renal toxicity in 8/16. In the other 8/16 patients tacrolimus was resumed after improvement in renal function. Thrombotic microangiopathy occurred in only 1 patient. Transplant related mortality (TRM) occurred in 6/68 (9%) by 100 days, and 12/59 (20%) by year 2. The overall survival (OS) was 85% (58/68) at 100 days, and 42% (25/59) at 2 years. In 62 patients engrafting stably, median survival has not been achieved for 21/62 in CR, and was 483 days for 41/62 not in CR at transplant (see figure below.) This data suggests that non-ablative hematopoietic cell transplantation with combination sirolimus and tacrolimus therapy can be accomplished with manageable nephrotoxicity, and sirolimus-based immunosuppression provides long term survival in patients with advanced hematopoietic malignancies. In many patients without GVHD tacrolimus may be discontinued early, with immunosuppression then provided by single agent sirolimus for an extended period. Download : Download high-res image (60KB) Download : Download full-size image Figure

Non-myeloablative conditioning has extended the use of allogeneic hematopoietic transplant to many previously ineligible patients but has to date been disappointing in patients with advanced acute myelogenous leukemia (AML). We added the immunosuppressive and antitumor agent sirolimus (rapamycin) to an established transplant regimen of fludarabine 25 mg/M2 days -7 through -3 and cyclophosphamide 1000mg/M2 days −7 and −6, with tacrolimus and methotrexate immunoprophyllaxis. 23 patients with AML were treated, with median age 59 (range 28–72) at transplant. 6 patients received matched sibling, 11–unrelated donor, 1–5/6 matched and 5-haploidentical (“haplo” −3/6 or 4/6 matched) transplants. The haplo recipients also received antithymocyte globulin on days −1, 1, 3, and 5. Only 7 patients in total were in CR, but all of these were at high risk for relapse because of prior MDS, chromosome status, or other features. 9 patients were in chemotherapy refractory progression, and 7 were primarily refractory to induction therapy. All patients engrafted. In patients without graft versus host disease by day 30 (9 patients) tacrolimus was discontinued between days 45 and 100 while sirolimus was continued. 12/23 patients survive at 61–903 days of followup post transplant (median 525) and 11/12 survivors are currently free of detectable leukemia. 3 of these 12 relapsed at 83, 88, and 243 days, but the first 2 of these have received chemotherapy and DLI and are in CR 771 and 311 days from relapse. The figure below shows overall and progression free survival (PFS). All survivors but the single patient undergoing therapy for progression have performance status 0 or 1 and are free of need for transfusion. 9/12 survivors continue on sirolimus therapy. Only 2 patients, both recipients of haploidentical cells, have died from transplant related causes. Non-myeloablative hematopoietic cell transplantation with sirolimus (rapamycin) based immunosuppression effectively treats many patients with advanced and poor prognosis AML. Given the very limited anti-leukemic activity of the conditioning chemotherapy, this suggests that disease control has been via graft versus leukemic effects alone or combined with anti-leukemic activity of the sirolimus. Download : Download high-res image (103KB) Download : Download full-size image Figure

Persistent thrombocytopenia after allogeneic marrow transplantation is associated with poor patient survival. To identify the mechanisms of the thrombocytopenia, we studied platelet and fibrinogen kinetics and antiplatelet antibodies in 20 patients between 60 and 649 days (median 90) after transplantation. Seventeen patients had isolated thrombocytopenia (less than 100 X 10(9) platelets/L): the marrow cellularity was normal in five patients and slightly reduced in 12, and there was no discrepancy between thrombopoiesis and myeloerythropoiesis. Three patients had pancytopenia following marrow graft rejection (two) and relapse of leukemia (one). Only three patients had evidence of increased platelet production, indicating that in most cases there is a poor marrow response to thrombocytopenia early after marrow grafting. There was no correlation between platelet count and splenic pooling, suggesting that hypersplenism was an unlikely mechanism of the thrombocytopenia. Although there was a direct relationship between platelet count and platelet survival, the reduction in platelet survival was greater than what could be explained by the fixed platelet removal found in thrombocytopenic patients; this suggests increased platelet destruction. Seven patients had intercurrent infections that reduced both platelet and fibrinogen survivals. In addition, platelet antibodies bound to autologous or marrow donor platelets were present in five of the 12 patients studied. Patients with antiplatelet antibodies had lower platelet counts (30 +/- 10 X 10(9)/L v. 49.1 +/- 28.7 X 10(9)/L, P less than 0.05) and platelet survivals (1.32 +/- 0.92 days v. 3.58 +/- 2.02 days, P less than 0.05) than patients without antiplatelet antibodies. Furthermore, platelet- bound autoantibodies were present in five of six patients with grade II- IV acute or chronic graft-versus-host disease (GVHD), but were not present in six patients free of GVHD (P less than 0.01). We conclude that persistent thrombocytopenia after marrow transplantation is most often secondary to increased platelet destruction mediated by multiple mechanisms and that platelet autoantibodies are found in patients with acute or chronic GVHD.