ALBERT

Description: Curative strategies for hematologic malignancies include alloHSCT, which has become a treatment option for older pts, as well as those with more extensive prior therapy and comorbidities. This has stimulated research on the development of less toxic but comparably effective approaches to transplantation at the level of cytoreduction, alternate graft sources, graft manipulation, and GvHD prophylaxis. To this end, between 7/2001 and 12/2005, we administered TCD HSCTs, derived from HLA-M or HLA-MM URDs, to 36 adult pts as treatment for a variety of hematologic malignancies on a clinical trial. The conditioning regimen was designed to reduce regimen related toxicity while preserving adequate immunosuppression to allow for engraftment. The TCD grafts allowed transplantation across HLA disparate pt-donor pairs without the use of additional renal and hepatotoxic GvHD prophylaxis. The conditioning regimen consisted of hyperfractionated total body irradiation (HFTBI) (1375 cGy), thiotepa (5mg/kg) x 2d, fludarabine (25mg/m2) x 5d and antithymocyte globulin (ATG) x 2d. HLA typing was performed by DNA SSOP analyses for A,B,C, DRB1, and DQB1, and donors were matched at ≥8 of 10 alleles. Pts received TCD-PBSC (n=29) or TCD-BM (n=7) from HLA-M (21 pairs) or HLA-MM (15 pairs) URDs. PBSCs were TCD by Isolex 300i CD34+ selection followed by sheep E-rosette depletion, and BMs were depleted with soybean agglutination and sheep E-rosette depletion. The median age was 40.6 (range 18–63)yrs; 10 pts ≥ 50 yrs. Diseases included AML and ALL CR1 (only standard or high risk), AML and ALL CR2, ALL ≥ CR3, acute biphenotypic leukemia, CML in CP, MDS, T-PLL. The median followup is 22 (range 6–55) mos. All evaluable pts engrafted neutrophils, 31 of 35 evaluable pts engrafted platelets. Four pts died of complications prior to platelet engraftment, including one pt with late graft failure. The 100d non-relapse mortality was 20% with most (〉50%) deaths due to infection. The incidence of acute (a) grade II–III and chronic (c) GvHD was low for the entire group of 36 pts at 11% and 28%, respectively, when compared to that of unmodified transplantation. The incidence of aGvHD was 14% and 7%, and cGvHD (majority - limited) was 26% and 30% for HLA-M and HLA-MM transplant pairs, respectively. Estimated 3 yr DFS is 60% for both HLA-M and HLA-MM transplants, and 83% for standard risk and 41% for high risk disease pts. Only one pt has relapsed. These results indicate that a transplantation strategy using HFTBI, thiotepa, fludarabine and ATG followed by TCD PBSC or BM, but without posttransplant immunomodulating agents, is well-tolerated in an older patient group (median age 40 yrs) even with HLA-MM URDs. Although this approach appears to provide an antileukemic effect for acute leukemia pts transplanted in remission of acute leukemia, this will need to be confirmed with longer followup.

Description: CD34 selected stem cell transplants (SCT) have shown similar survival rates as unmodified SCT, with lower incidence of acute and chronic graft-versus-host disease (GVHD). A common conditioning regimen for patients with advanced myelodysplastic syndrome (MDS) undergoing CD34 selected SCT is a combination of busulphan, melphalan, fludarabine, and anti- thymocyte globulin (ATG). The ideal area under the curve (AUC) and overall dose intensity of busulphan is unknown in these pts. We aimed to study the relationship between busulfan AUCs and transplant outcomes in this pt population. This retrospective analysis included 68 pts with advanced MDS (RAEB-I and higher) who underwent CD34 selected SCT between 2000-2012. Median age was 58.05 yrs (26-73). There were 36 women (52.9%). HCT CI was ³ 3 in 37 pts (54.4%). MDS subtype at diagnosis by WHO criteria was: RA/RCMD-19 (all progressed to RAEB/AML), RAEB-I 20 &RAEB II 29; and by IPSS-R criteria in 65 pts: very low risk-4, low risk-9, intermediate risk-14, high risk-20 & very high risk-18. All pts were conditioned with busulphan IV 0.8 mg/kg dose, melphalan 140 mg/m2, fludarabine 125 mg/m2 & ATG . Thirty-nine pts received 10 doses of busulphan and 29 pts 12 doses. The dose was increased to reduce the relapse rate. Pharmakokinetic studies were done after first busulphan's dose and based on results adjustments were made to achieve a target dose of 1025-1315µM x min. G-CSF mobilized donor peripheral blood stem cells underwent CD34+ selection and depletion of T cells using CliniMACS immunomagnetic selection columns (Milteny Biotec). Donors were HLA matched, 48 (18 related & 30 unrelated) or mismatched unrelated, 20. The median first-dose busulphan AUC was 1,206 (723-2,180). In 27 pts (39.7%) this was within target range of 1,025-1,315 with 16 pts (23.5%) below and 25 (36.7%) above. The median total busulphan exposure for all pts was 12,822 (9,513-15,754), with 1st quartile range of 9,513-12,181 and 4th quartile range of 13,664-15,754. The median total exposure in the 10 doses group (group 10) was 12,520 (9,513-15,754) and in the 12 doses group (group12) 13,420 (9,860-15493). The 2-years overall survival (OS) was 61.5% (CI 44.5-74.7) in group 10 and 55.2%(35.6-71) in group 12 and 2-years relapse free survival (RFS) was 56.4% (39.6-70.2) in group 10 and 51.7% (32.5-67.9) in group 12. The 2-years cumulative incidence of relapse was 15.4% (CI 3.9-26.9) in group 10 and 13.8% (CI 0.9-26.6) in group 12. The non-relapse (NRM) mortality at 2 years was 28.2% (13.8-42.6) in group 10 and 34.5% (16.7-52.2) in group 12. aGVHD grade II-IV was 12.8% (2.2-23.5) in group 10 vs 23.1% (6.5-39.7%) in group 12. None of these differences were statistically significant. Further analysis by quartiles showed no differences in OS, RFS, relapse and NRM between the 4 groups. However, grade II-IV acute GVHD was significantly higher in the 4th quartile exposure, 35.6% (8.9-62.3) vs 5.9% (0-17.5), 11.8% (0-27.6) and 17.6% (0-36.4) in the 1st, 2nd and 3rd quartiles (p=0.046) (table 1). In thishomogenous cohort of pts, total busulphan exposure was only found to be associated with grade II-IV aGVHD, with higher incidence seen in pts who had exposure 〉13,664. Donor mismatch status was not associated with higher aGVHD in this cohort and therefore can not explain the increased aGVHD seen with higher busulphan exposure. A trend for better transplant outcomes was seen with total exposure of 12,182- 13,663 (2nd and 3rd quartiles); though the differences were not statistically significant. In CD34 selected allo-HSCT for pts with advanced MDS, the intensity of the conditioning has an impact on transplant outcomes and therefore determining the range of busulphan that offers best survival with minimal GVHD has important clinical implications. Table 1. Transplant outcomes (cumulative incidence with 95% CI): Total exposure 6-months CI ofaGVHD II-IV 2-year CI of Relapse 2-year CI NRM 2-year CI OS 2-year CI RFS Q1: 9,513-12,181, n=17 5.9 (0-17.5) 35.3 (11.6-59) 23.5 (2.4-44.7) 52.9 (27.6-73) 41.1 (18.6-62.6) Q2: 12,181-12,822, n=17 11.8 (0-27.6) 11.8 (0-27.7) 23.5 (2.6-44.4) 70.6 (43.1-86.6) 64.7(37.7-82.3) Q3: 12,823-13,663, n=17 17.6 (0-36.4) 5.9 (0-17.5) 35.3 (11.7-58.9) 58.8 (32.5-77.8) 58.5 (32.5-77.8) Q4: 13,664-15,754 n=17 35.6 (8.9-62.3) 5.9 (0-17.4) 41.2 (16.8-65.6) 52.9 (27.6-73) 52.9 (27.6,-73.0) p value* overall: 0.185, Q4 vs others: 0.046 0.221 0.409 0.663 0.540 Figure 1. Figure 1. Disclosures Giralt: SANOFI: Consultancy, Honoraria, Research Funding; CELGENE: Consultancy, Honoraria, Research Funding; AMGEN: Consultancy, Research Funding; JAZZ: Consultancy, Honoraria, Research Funding, Speakers Bureau; TAKEDA: Consultancy, Honoraria, Research Funding.

Description: Adoptive immunotherapy with transplant donor-derived virus specific T cells is an effective strategy for the treatment of CMV viremia and disease arising after an allogeneic hematopoietic stem cell (HSCT). At our center this approach has become a standard part of the armamentarium of CMV directed therapy. However, donor-derived CMVpp65-specific cytotoxic T cells (CMV-CTLs) are not available for patients transplanted from a seronegative or cord blood donor. In addition, in the HLA disparate transplant setting the CMV-CTL line derived from non-identical donors may be restricted by non-shared HLA alleles. For these patients as we have previously reported, treatment with in vitro expanded CMV-CTLs derived from an HLA partially matched third party donors is an option. One particularly difficult clinical situation is the treatment of patients who develop CMV disease involving the sanctuary sites of the central nervous system and retina. We have treated 12 patients with primary donor derived (n=1) or third party (n=11) CMV CTLs for retinitis (7) or meningitis/encephalitis (4) or both (1). Recipients of hematopoietic stem cell transplant (HSCT) had undergone T cell depleted (5) conventional (1) or cord blood (4) transplantation. One patient was treated after solid organ transplantation and one for HIV related CMV retinitis. Third party CMV CTLS were selected from a bank of 132 lines generated under GMP conditions from normal HSCT donors specifically consented for use of their T cells in patients other than their designated transplant recipient. Third party CMV-CTLs were selected on the basis of HLA matching at a minimum of 2/8 recipient alleles and HLA restriction of the T cells by one or more HLA alleles present in the patient. A total of 10 distinct third party CMV-CTL lines and one (1) donor derived line were used. Patients received infusions of CMV-CTLs after failing a median of 146 (43-419) days of prior therapy with a median of 4 anti-viral agents. Patients received 3 weekly infusions of CMV-CTLs at doses of 1 x 10e6 T cells/kg (n=10) 2 x 10e6 T cells/kg (n=1) and 0.5 x 10e6 T-cells/kg (n=1) and were eligible to receive additional cycles of cells if they had no toxicity five weeks after the start of cellular therapy. One patient was evaluated only for toxicity as efficacy was confounded by anti-viral therapy required for treatment of varicella zoster. Of the 11 evaluable patients, 7 achieved CR, 1 PR (clinical improvement in disease and a 3 log decrease in viral load) and 1 SD. All but one of these responses were durable. One patient who had achieved a CR had recurrence of low grade viremia which was not retreated due to his overall medical deterioration. The two patients with progression of disease ultimately died of CMV. Patients were monitored for expansion of CMV-CTLs by CMV-specific interferon gamma and where appropriate tetramer analysis. Responding patients consistently had detectable expansion of CMV-specific CTL populations. In addition, in one patient, undergoing serial lumbar punctures, we were able to detect third party CMV-CTLs in the CSF. There were limited toxicities associated with CMV-CTL infusions. No patient developed de novo GvHD or a flare of prior GvHD. This study demonstrates a high response rate among patients with otherwise refractory CMV chorioretinitis or meningoencephalitis following adoptive therapy with primary donor or third party CMV-CTLs; thus demonstrating the capacity of adoptively transferred CMV-CTLs to treat disease in these sanctuary sites without toxicity. When selected based on restriction through shared alleles, third party CMV-CTLs are effective despite significant HLA disparity. The bank of CMV specific T cells can provide an immediate source of HLA partially matched appropriately restricted T cells for adoptive immunotherapy to treat CMV disease affecting the CNS. This enables treatment early in the course of disease with CMV-CTL lines previously prepared and characterized in terms of HLA restriction. This approach is anticipated to maximize the response rate as well as minimize toxicity from anti-viral therapy. Disclosures Prockop: Atara Biotherapeutics: Other: I have no financial disclosures, but Atara Biotherapeutics has exercised a licensing agreement with Memorial Sloan Kettering Cancer Center and MSKCC and some investigators at MSKCC have a financial interest in Atara.. Hasan:Atara Biotherapeutics: Research Funding. O'Reilly:Atara Biotherapeutics: Research Funding.

Description: TP53 alterations detected by chromosome 17p deletion, oncogenic mutation, or p53 protein overexpression portend extremely poor prognosis for patients with mantle cell lymphoma (MCL), despite aggressive upfront therapy including consolidative high-dose therapy autologous stem cell transplant and; more recently, novel agents such as ibrutinib or lenalidomide. We reviewed outcomes of 42 patients with available TP53 status who had received reduced-intensity/non-myeloablative conditioning (RIC/NMA) allogeneic hematopoietic cell transplant (allo-HCT) for MCL at our institution and examined the impact of TP53 alteration and other clinical factors on outcomes. Nineteen patients had TP53 alterations including 17p deletion (n=3), oncogenic mutation (n=7), and strong p53 protein overexpression by immunohistochemistry (n=9). There were no differences in demographic or clinical characteristics among patients with and without TP53 alterations (Table 1). With a median follow-up for survivors of 23 months (range 4-119), the one-year overall survival (OS) and progression-free survival (PFS) is 87% (95% CI 72-94) and 74% (95% CI 57-85), respectively (Figure 1A). The one-year cumulative incidence of relapse and non-relapse mortality is 16% (95% CI 6-29) and 10% (95% CI 3-22), respectively (Figure 1B). The cumulative incidences of grade II-IV acute GVHD is 38% at 180 days (95% CI 24-53), and of any chronic GVHD is 33% at three-year (95% CI 17-49). Importantly, there is no statistically significant difference in OS (p=0.582, Figure 1C), and cumulative incidence of relapse (p=0.715, Figure 1D) among patients with and without TP53 alterations. In univariate and multivariate analyses, we find that only Ki67 〉30% is a significant predictor of PFS (HR 4.1, 95% CI 1.1-15.5, p=0.024), and that only Karnofsky Performance Status (KPS)

Description: Abstract 2296 Poster Board II-273 CB transplantation (CB-T) may be curative for patients with high-risk or advanced hematologic malignancies. However, given there are no randomized trials comparing survival after CBT with the more traditional approach of matched related donor transplantation (MRD-T) or unrelated donor transplantation (URD-T), how CB-T compares to MRD-T and URD-T transplantation is not established. Therefore, we conducted a retrospective study comparing survival after CB-T (n=67) with MRD-T (n=96) and URD-T (n=163) performed 10/05-3/09 for the treatment of hematologic malignancies. Our hypothesis was that 1 year survival is comparable between hematopoietic stem cell (HSC) sources. Consecutive adult and pediatric recipients of first allograft for the treatment of acute leukemia in remission (CR1-3), myelodysplasia (MDS, ≤5% blasts at work-up), or non-Hodgkins or Hodgkin lymphoma were eligible for analysis. The median age of CB-T recipients (37 years, range

Description: The incidence of pertussis in the United States has steadily increased over the last decade particularly in adolescents and adults. In 2005, in an effort to reduce pertussis in these populations, two vaccines containing tetanus, reduced diphtheria and pertussis toxoids (Tdap) were approved. The two Tdap vaccines contained the same amount of tetanus toxoid (TT) but differ in the amount of diphtheria and pertussis toxoid per dose as well as their indicated age range. In 2006, the Advisory Committee on Immunization Practices recommended that all adolescents and adults receive a single dose of Tdap. Currently, there are limited data on the immunonogenicity of these vaccines in alloHCT patients. Since 2005, 64 alloHCT recipients have received Tdap at our center. The vaccine administered is approved for individuals 11 to 64 yrs of age and contained 2.5 ug of pertussis toxoid (PT), 2.5 Lf diphtheria toxin, and 5 Lf tetanus toxoid (TT) per dose. The median age at HCT was 19 years. The median age (range) at vaccination was 25.2 years (10–64) years. No patient has reported a significant adverse event, including local site reactions or fever 〉38. Pre and post vaccine titers are currently available in 41 patients transplanted for acute leukemia (n=22), CML (n=4), MDS (n=5), NHL (n=4), Hodgkin’s disease (n=1), hemoglobinopathy (n=4), or Wiskott Aldrich syndrome (n=1). Stem cell donors were an HLA matched sibling (n=23) or unrelated donor (n=18). Fifty-nine percent of patients received T-cell-depleted allografts and the remaining 41% received unmodified allografts. Patients were vaccinated at a median of 4.5 years (range: 0.8–14 years) after transplantation. The majority of patients had no detectable pertussis titers prior to immunization. In an effort to provide early protection against pertussis, ten patients received Tdap as their primary tetanus vaccine. The remainder received Tdap as a booster following one (n=4), two (n=3) or 3 (n=24) age appropriate tetanus/diphtheria containing vaccines. Response to TT (seroconversion 〉0.15 IU/ml or 〉3 fold increase) was significantly better when Tdap was used as a booster vaccine compared with use as the initial tetanus vaccine (74% vs 20%, p=0.003). Response to TT and diphtheria toxoid was also significantly better in patients who received Tdap following a series of three tetanus/diphtheria containing vaccines, compared with one or two (p=0.03). In contrast, only 7 patients developed a 〉2 fold increase in antibody titer against PT. Of these 7 responders, 6 were 1 Tdap and/or donor immunization prior to stem cell harvest, should be explored.

Description: Older patients are at increased risk for complications and death following allogeneic hematopoietic cell transplantation (allo-HCT). Traditional transplant-specific prognostic indices such as hematopoietic cell transplant comorbidity index (HCT-CI) may not capture all underlying geriatric vulnerabilities, and in-depth evaluation by a geriatrician prior to transplant may not always be available. We hypothesize that routine pre-transplant assessments by interdisciplinary clinical providers including advanced practice providers, nursing staff, physical therapists, occupational therapists, and dietitians, as well as common laboratory tests, may uncover additional geriatric deficits. Using an institutional database and the electronic medical records of 406 adults age 60 years and older (range 60-78.7) who underwent first allo-HCT for hematological malignancies from 2010 to 2016, we examined the prevalence and the prognostic impact of pre-transplant geriatric deficits identified by interdisciplinary clinical providers including geriatric domains of functional activity, cognition, medication, nutrition, and mobility (Table 1), and by routine laboratory tests. With a median follow-up of 39 months for survivors, the 3-year probability of overall survival (OS) and progression-free survival was 47% (95% CI 42-53) and 40% (95% CI 35-45), respectively. The 2-year cumulative incidence of non-relapse mortality (NRM) was 26% (95% CI 22-29). Among pre-transplant geriatric and laboratory variables, we found that impairment in instrumental activities of daily living (IADL) and pre-transplant ferritin level ≥1200 was independently associated with increased NRM and inferior OS. In the multivariate analysis, HCT-CI ≥3, IADL impairment, ferritin level ≥1200, and Karnofsky Performance Scale (KPS)

Description: To ascertain the therapeutic potential of non-TBI-based conditioning for CD34+ HPC-selected , T cell-depleted allografts, we conducted a trial comparing our standard regimen, arm (A) 1375cGy HFTBI+ thiotepa,5 mg/kg/day x 2 days + cyclophosphamide 60 mg/kg/day x 2 days vs. arm (B) Busulfex 0.8 mg/kg/6h x12 (dose adjusted) + melphalan 70 mg/kg/day x 2 + fludarabine 25 mg/m2/day x5 and arm (C) Clofarabine 20 mg/m2/day x 5 + melphalan 70 mg/m2/day x 2 + thiotepa 5 mg/kg/day x2, as preparation for T-cell depleted CD34+ PBSC transplants from GCSF-mobilized leukocytes fractionated with the CliniMACS device. Primary endpoints were engraftment, GVHD, transplant-related mortality (TRM) and 2 yr OS and DFS (Confer Table). Stratification of pts to arms A (standard), B or C was based on the patient’s disease, disease stage and clinical factors such as age, prior therapy or comorbidities enhancing risks of TBI. Arm B was the non-TBI arm predominantly used for myeloid and Arm C for lymphoid malignancies. Prior to transplant, recipients of HLA-matched or non-identical transplants received rabbit thymoglobulin at 2.5 mg/kg/day x2 or 3 days respectively, to prevent graft failure. No GVHD drug prophylaxis was given post transplant. A total of 181 consecutive patients, accrued between 5/13/2010 and 6/12/2013, were analyzed (81 in arm A, 78 in arm B, 22 in arm C). These pts have been followed for a median of 12.1 months. Donors were related or unrelated and HLA-matched for 74% of the patients and 1-2 HLA allele disparate for 26%. Median age for the entire group was 50.5 years, with older pts predominating in the non-TBI groups (medians arm A ,31.9 yrs; arm B , 61.9 yrs; arm C, 44.6 yrs). The CD34+ PBSC transplants provided a mean dose of 9.7x106 CD34+ progenitors/Kg (range 1.4-89.7) and 4.5x103 CD3+ T-cells/Kg (range 0.6-25.3). All pts engrafted; but 2 pts (2.5%) in arm B experienced late graft failure, one of whom was reconstituted after a secondary graft. Overall the incidence of grade II-IV acute GVHD was 18%, and 14% for recipients of HLA-matched grafts. TRM at 1 year was 10% in Arm A, and 15% in Arms B and C. Two year OS and DFS for each arm are: arm A, 66.7% and 58.4%; arm B 62.3% and 59.5%; arm C 52% and 53%. For the 101 pts who received standard risk transplants (i.e., pts with high risk forms of AML, ALL or NHL in 1o CR, AML in 2o CR, MDS RA/RCMD, CML in 1o CP or MM in CR1, VGPR or first PR ), 2 year OS and DFS are: arm A 68% and 62%; arm B 67% and 66%; arm C 86% and 86%, with relapse rates at 2 yrs of: arm A 23%, arm B 15%, and arm C 14%. These results thus identify two non-TBI-based conditioning regimens that secure consistent engraftment of rigorously T-cell depleted allogeneic HSCT and can yield favorable long-term DFS and OS with low incidences of GVHD and relapse. Table 1 Overall Results Graft 1 Year Acute GVHD II – IV 2 Year PTs ENG Failure TRM ALL HLA-Matched O.S. DFS ARM A 81 81 0 10% 23% 17% 66.7% 58.4% ARM B 78 78 2 15% 12.3% 13% 62.3% 59.5% ARM C 22 22 0 15% 27% 20% 52% 53% Disclosures: No relevant conflicts of interest to declare.

Description: Abstract 4029 Poster Board III-965 Paroxysmal nocturnal hemoglobinuria (PNH) is a debilitating and life-threatening hematopoietic stem cell disorder characterized by unregulated activation of the complement system leading to chronic intravascular hemolysis and an inflammatory prothrombotic state. PNH evolves from the clonal expansion of hematopoietic stem cells with complete or marked loss of terminal complement inhibitors CD55 and CD59 from the surface of hematopoietic cells, rendering red blood cells susceptible to terminal complement-mediated hemolysis, and white blood cells and platelets to terminal complement-mediated activation. Many of the clinical complications of PNH including severely impaired quality of life and life-threatening thromboembolism (TE), chronic kidney disease, pulmonary hypertension, end organ damage, fatigue, abdominal pain, dysphagia and dyspnea are a result of terminal complement-mediated activation. While many patients with PNH have anemia, hemoglobin and transfusion requirements may not adequately reflect the burden of disease due to hemolysis since these parameters are influenced by many factors unrelated to hemolysis or complement activation including bone marrow function, patient specific factors and physician clinical assessment. In order to understand the clinical burden of PNH in patients with no history of transfusions, we identified and evaluated 44 patients who had not received prior red cell transfusions and were considered a candidate for treatment with the terminal complement inhibitor eculizumab based on the physician's individual clinical assessment. This group of never-transfused patients included patients in France, Italy, the Netherlands, Australia, and the US. In this group, ages ranged from 16 to 84 years (median 41 yrs) and duration of diagnosis ranged from 1 month to 30 years (average 3.8 years). The median PNH granulocyte clone size was 72%, (n=36). Hemoglobin level ranged from 6.0 to 14.9 g.dL (median 9.8 g/dL, n=37). Almost one quarter (9/37) of these patients had hemoglobin ≥11.0 g/dL and 21/37 had Hgb ≤ 10.0 g/dL. The median LDH was 1,463 U/L (range from 180 to 5,950 U/L; n=39). Thrombosis was relatively common in this patient population – 28% (12/43). Interestingly, TE was similarly observed in patients with PNH granulocyte clones ≤ 50% (33%, n=9) and in patients with PNH granulocyte clone greater than 50% (30%, n=27), confirming that TE was not at all confined to patients with a large clone. Impaired quality of life was reported in 87% of patients (n=39) by the physician or patient, and only 5 patients (13%) reported normal or good quality of life. Impaired quality of life similarly affected patients with smaller and larger PNH granulocyte clones in this population. Impairment included the following assessments: mild impairment, disabling or moderate fatigue, disabling abdominal pain, shortness of breath with exertion, or poor quality of life. In conclusion, despite a history of no transfusions, patients presenting for treatment with the terminal complement inhibitor eculizumab demonstrated evidence of unregulated terminal complement activity, as measured by elevated levels of LDH. These never-transfused PNH patients had significant clinical evidence of TE and impaired quality of life. These findings underscore the central role of terminal complement activity, rather than anemia or transfusion requirements, in driving the significant disease burden and guiding the treatment of patients with PNH. Parameter Median Range Age (n=44) 41 years 16 to 84 Time Since Diagnosis (n=38) 15 months 1 month to 30 years Hemoglobin (n=37) 9.8 g/dL 6.0 to 14.9 LDH (n=37) 1,463 U/L 180 to 5,950 % of PNH patients Evidence of TE (n=43) 28% Evidence of Impaired Quality of Life (n=39) 87% Disclosures: Muus: Alexion Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Risitano:Alexion Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Castro-Malaspina:Alexion: Consultancy, Honoraria. Jones:Alexion: Speakers Bureau. Socie:Alexion: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Description: Introduction: Allogeneic hematopoietic cell transplantation (HCT) offers a potentially curative therapy in patients (pts) with hematologic malignancies; however, treatment-related mortality (TRM) remains a concern. Strategies to improve post-HCT neutrophil recovery (NR) and immune reconstitution (IR) to decrease TRM need to be explored. Murine models of allogeneic HCT suggest that fractionated hematopoietic progenitor cell (HPC) infusion may improve engraftment through improved access of HPCs to a viable hematopoietic niche (Felfly et al., 2010; Bhattacharya et al., 2009). The impact of fractionated HPC infusion on NR, IR and overall survival (OS) has not been prospectively studied in humans. Objective: Determine the impact of bulk vs. fractionated HPC infusion on NR after allogeneic HCT, as defined by the time to achieve an absolute neutrophil count (ANC) of 〉 500. Secondary objectives included evaluations of OS, TRM, relapse and additional parameters of IR. Methods: In this randomized phase 2 study of bulk vs. fractionated HPC infusions, pts with hematologic malignancies 〈 75 yrs underwent HCT, receiving unmodified or CD34 selected allografts from HLA-matched or mismatched related or unrelated donors (NCT01596257). Patients were randomized to receive HPC infusion as a bulk (Bulk Arm) or in fractions (Fractionated Arm): 4x10E6 CD34+ cells/kg recipient weight infused on day 0, with the remaining HPCs CD34+ cell selected then infused on days 2, 4 and 6 post-HCT, in equally distributed aliquots. Randomization was stratified by allograft type (unmodified vs. CD34 selected). Patients whose donor failed to collect at least 7x10E6 CD34+ cells/kg recipient weight received bulk HPC infusions regardless of randomization, for safety. These pts continued HCT on study, but were replaced until each arm reached a target accrual of 36 pts. Per protocol, these pts were not included in this modified intent to treat analysis (ITT). Patients with at least 100 days of follow up on 6-30-15 were included in the current analysis. Results: Of 124 pts enrolled between 2012 and 2015, 109 are evaluable. Patient and transplant characteristics are outlined in Table 1. Median age was 60 yrs. Donors of 41 pts (38%) failed to mobilize the minimum CD34+ cell dose and were not included in the analysis. Of 68 pts 33 were randomized to the Bulk Arm and 35 to the Fractionated Arm. Median CD34+ cell doses were 9.8x10E6/kg recipient weight in the Bulk Arm and 7.6x10E6/kg recipient weight in the Fractionated Arm. All pts engrafted. Median time to ANC of 〉 500 was 11 days in both arms (Figure 1). Day +180 median CD4+ cell count was 173.5 cells/µl in the Bulk Arm and 168 cells/µl in the Fractionated Arm. With a median follow up of 19 months in surviving pts, the estimated 2-yr OS was 78% and 70% for pts in the Bulk vs. Fractionated Arms, respectively (Figure 2). The estimated 2-yr cumulative incidences of TRM were 9% and 7% in pts in the Bulk vs. Fractionated Arms, respectively. The estimated 2-yr cumulative incidences of relapse were 27% and 26% in pts in the Bulk vs. Fractionated Arms, respectively. The cumulative incidences of grades II-IV (grades III-IV) acute GVHD were 30% vs. 14% (6% vs. 0%) in pts in the Bulk vs. Fractionated Arms, respectively. Conclusion: In this randomized modified (ITT) analysis, fractionated infusion of HPCs in pts undergoing allogeneic HCT did not statistically significantly impact NR or OS when compared to pts receiving bulk HPC infusion. In addition, CD4+ cell count on day 180, TRM and relapse rates were similar between the two groups. We also observed that with current mobilization techniques it was unlikely that more than 60% of normal donors would be able to collect more than 7x10E6 CD34+ cells/kg recipient weight for adult recipients. Table 1. KEY-HCT-hematopoietic stem cell transplant, Flu-Fludarabine, Mel-Melphalan, Bu-Busulfan Table 1. KEY-HCT-hematopoietic stem cell transplant, Flu-Fludarabine, Mel-Melphalan, Bu-Busulfan Figure 2. Neutrophil recovery in patients receiving bulk vs. fractionated infusions of hematopoietic progenitor cells Figure 2. Neutrophil recovery in patients receiving bulk vs. fractionated infusions of hematopoietic progenitor cells Figure 3. Overall survival in patients receiving bulk vs. fractionated hematopoietic progenitor cell infusions. Figure 3. Overall survival in patients receiving bulk vs. fractionated hematopoietic progenitor cell infusions. Disclosures Off Label Use: We discuss off-label use of busulfan, melphalan, cyclophosphamide, fludarabine, thiotepa, total body irradiation, tacrolimus and methotrexate. We also discuss off-label use of CD34 selected progenitor cell infusion. . Perales:Merck: Honoraria; Amgen: Honoraria; NMDP: Membership on an entity's Board of Directors or advisory committees; Astellas: Honoraria; Takeda: Honoraria. Giralt:Celgene: Honoraria, Research Funding; SANOFI: Honoraria; TAKEDA: Honoraria; JAZZ: Honoraria; MILTENYI: Honoraria; Johnson and Johnson: Research Funding.