ALBERT

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). This approach is not readily applicable if the donor is seronegative or not available to provide lymphocytes for in vitro expansion for CMV specific cytotoxic T lymphocytes (CMV-CTL) lines or if the CMV CTL lines derived from non-identical donors are restricted by non-shared HLA alleles. We and others have previously presented results indicating that treatment with in vitro expanded CMV-CTLs derived from an HLA partially matched third party donors can effectively treat CMV infections in the post-transplant setting. However, the patient population most likely to benefit from this approach has not been well defined. Patients at especially high risk of succumbing to CMV infection include those who acquire resistance to antiviral therapy. We now present results of treatment with banked off-the-shelf third party CMVpp65 specific CTLs in patients with genetically defined mutations in the UL54 DNA polymerase and UL97 kinase CMV genes predicting resistance to antiviral agents. Fifteen recipients of HSCT with mutations defined prior to the start of cell therapy were treated. All 15 had mutations associated with resistance to ganciclovir. Overall 5 had resistance to ganciclovir, foscarnet and cidofovir, 5 had resistance to ganciclovir and foscarnet, one had resistance to ganciclovir and cidofovir and 4 had resistance to ganciclovir alone. Third party CMV-CTLs were selected on the basis of HLA matching at high resolution 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. 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 the designated transplant recipient. These 15 patients had a median age of 60.5 (7.4-70.1) years and started therapy with CMV-CTLs a median of 157 (70-564) days after reactivation of CMV. Four of these patients had CMV disease while 11 were treated for viremia alone. Prior therapy in this cohort included foscarnet (N=15) ganciclovir and/or valganciclovir (N=14) and cidofovir and/or brincidofovir (N=9). Each cycle of CMV-CTLs consisted of 3 weekly infusions of 1x106 T-cells/kg/infusion. These 15 patients received a median of 2 (1-3) cycles of CMV-CTLs. CMV-CTLs were well tolerated and there were limited toxicities. Six patients experienced AEs of which one grade 3 and one grade 4 AE were deemed possibly related to infusions with CMV-CTLs. Overall 11/15 (73.3%) patients responded to CMV-CTL therapy including 2 patients with disease with 6 CRs and 5 PRs. Overall survival at 6 months in the 11 responders and 4 non-responders was 72.7% and 25.0% respectively. Within the 6 month follow-up one of the 11 responding patients died of CMV while 3 of the 4 non-responding patients died of CMV. These results indicate that third party donor derived "off-the-shelf" CMV-CTLs can effectively treat CMV viremia or disease in patients not responding to antiviral therapy with demonstrated genetic resistance to antiviral agents. Figure 1. Figure 1. Disclosures Doubrovina: Atara Biotherapeutics: Consultancy, Research Funding. Hasan:Atara Biotherapeutics: Consultancy, Research Funding. Koehne:Atara Biotherapeutics: Consultancy.

Description: Twenty five patients have been enrolled on this trial to date. There were 14 males and 11 females aged 0.6–54 years. Patients’ diagnoses and stage included: NHL in CR2 or refractory (n=2), AML (n=7), including 5 pts with secondary AML, ALL 〉 CR3 (n=4), CML in CP2 (N=1) and high risk MDS (n=11) including 5 pts with secondary MDS. Eight pts had a matched related donor, 14 pts an unrelated donor and 3 pts a mismatched related donor. Cytoreduction consisted of busulfan (Bu) (0.8–1 mg/Kg/dose x 10 doses), melphalan (Mel) (70 mg/Kg/day x 2) and fludarabine (Flu) (25 mg/m2/day x 5). Graft rejection prophylaxis included rabbit ATG (Thymoglobulin) (2.5 mg/Kg/day x 2). Four pts tolerated only one of two doses of the ATG, 2 pts received equine ATG and one pt Alemtuzumab. Twenty one pts received G-CSF mobilized peripheral blood stem cell transplants that were T-cell depleted by CD34 selection and E-rosetting while the other four pts received Soybean agglutinin E-rosette depleted marrow grafts. Cell doses were 1.3–20.5 x 106 CD34 cells/Kg. and 0 -100 x 103 CD3 cells/Kg. Engraftment occurred in 24 pts. One pt suffered a graft failure; This pt had initial low busulfan levels, and received bone marrow derived stem cells with a low cell dose from a 5/6 HLA-matched unrelated donor. Acute graft-versus-host disease occurred in four pts: grade 1 (n=2) and grade 2 (n=2) and no pts developed any grade 3-4 severe GvHD. Two patients were diagnosed with chronic GvHD: localized (n=1) and extensive (n=1). Two patients developed sepsis early post BMT, with secondary multi organ failure and early mortality, while for the rest of the patients, regimen-related toxicity was acceptable. Relapse occurred in 9 pts. Mortality included 7 pts from relapse, two pts from sepsis and multi-organ failure, 3 pts from infections, and one pt from unknown causes. The overall survival (OS) and disease-free survival (DFS) at 2 yrs for the entire patient cohort were respectively 44% and 42 %; The DFS was 50% for patients with secondary MDS or AML. In summary, the cytoreduction with Bu Mel and Flu allowed consistent engraftment of T-cell depleted grafts and was associated with acceptable outcome for patients with secondary MDS or AML.

Description: Between 05/98 and 06/04, 15 consecutive patients with FA received hematopoietic stem cell transplants (SCT) from alternative donors at our Center. There were 7 males and 8 females aged 5 to 24 years (median 11.5). Hematologic diagnoses included aplastic anemia (AA) (N=5), myelodysplastic syndrome (MDS) in RAEB (N=4), RAEBT (N=1) or acute myelogenous leukemia (AML) (N=5). High risk features included: Age 〉 20 years (n=4), prior multiple transfusions (n=11), prior androgen treatment (n=12), prior infections (n=10), or advanced MDS or AML (n=9). Eight pts had related mismatched donors transplants with respective matching at 3/6 (6/10), 4/6 (6/10), 4/6 (7/10) (n=2)), 5/6 (8/10) (n=3) and 5/6 (9/10) HLA-antigens. Seven pts had unrelated donors transplants with respective matching at 5/6 (7/10), 5/6 (8/10) (n=2), 5/6 (9/10) and 6/6 (10/10) (n=3) HLA-antigens. Cytoreduction included single dose total body irradiation (SDTBI) (450 cGy), fludarabine (Flu) (30 mg/m2 x 5) and cyclophosphamide (Cy) (10 mg/Kg x 4). Immunosuppression included rabbit anti-thymocyte globulin (Thymoglobulin) and tacrolimus for all patients. Grafts were G-CSF mobilized CD34+ and E-rosette negative (E-) peripheral blood stem cell transplants for 12 pts and soybean agglutinin negative (SBA-) and E-rosette negative marrow transplants for 3 pts. Cell doses of the grafts were 1.5 – 29.6 x 106 CD34 cells/Kg and 0 – 26 x 103 CD3 cells/Kg. As evidenced by RFLP or FISH, all 15 evaluable pts were fully engrafted and complete chimeras. Fourteen pts were evaluable for graft-versus-host disease (GvHD). GvHD of the skin and of the gut was suspected in two pts but resolved completely prior to immunosuppressive treatment. With a median follow-up of 2.5 years (range 0.2–6), 13 of 15 pts are alive and 11 of 15 are alive disease-free. There were two deaths: one pt died from sepsis/ARDS at 2 months post SCT and one pt from pneumonitis/ARDS and EBV-infection 6 months post SCT. Three pts relapsed (MDS-RAEB x 1 – AML x 2): One pt relapsed 7 months post transplant, received a 2nd transplant from the same donor following busulfan and Flu and is alive, disease-free 18 months post SCT, while the other two pts are awaiting a second SCT. In summary, this cytoreductive regimen used with T-cell depleted stem cell transplants from unrelated or HLA-mismatched related donors for the treatment of high risk patients with Fanconi anemia, results in rapid hematopoietic engraftment and lymphohematopoietic reconstitution with minimal GVHD and a high disease-free survival.

Description: The standard cytoreduction for bone marrow transplantation (BMT) of pts with HGBpathies has been the combination of Busulfan (BU) and Cyclophosphamide However, for pts with advanced disease, high rates of graft rejection and toxicity were reported. For such high risk pts, a BU and Fludarabine (FLU) cytoreductive combination was used at low dose in the context of non-myeloablative BMT and was associated with a poor outcome with high rates of graft rejection. In view of the low toxicity associated with the BU-FLU combination, we used both agents at higher, potentially myeloablative doses for the cytoreduction of six pts with high risk HGBpathies. Between 12/00 and 04/05, 4 pts with thalassemia (Thal) and 2 pts with sickle cell disease (SCD), including 2 males and 4 females aged 4.6–15.3 years were transplanted using this regimen. All 4 pts with Thal had advanced Lucarelli Class 2 disease, while the 2 pts with SCD had stroke, recurrent vaso-occlusive crises (VOC), sickle lung disease and alloimmunization (n=1) and recurrent VOC, acute chest syndrome and osteomyelitis (n=1). Cytoreduction included intravenous BU (0.8–1 mg/Kg/dose x 14), FLU (30 mg/m2/day x 5) and Rabbit ATG (2.5 mg/Kg x 2). GvHD prophylaxis consisted of Tacrolimus (n=3) or cyclosporine (n=3) and methotrexate (n=5) or Steroids (n=1). Pts received an unmodified BMT from their HLA-identical sibling with total nucleated cell doses of 0.7–5.7 x 108 cells/Kg. The regimen was well tolerated with minimal toxicity. With a median follow-up of 21.5 mo (range 3–55 mo), all 6 pts are disease- and transfusion- free. There was no graft rejection and no GvHD. Chimerism status for pts with Thal was 98–100% donor, 5 mo to 2 years post BMT, while for the 2 pts with SCD, it was mixed with 50 and 80% donor cells at 3 mo and 2 years post BMT. The pt with 50% donor cells received a low graft cell dose (0.7 x 108 nucleated cells/Kg). One additional pt with SCD and a history of 2 strokes and moya-moya disease received BU FLU + melphalan (70 mg/m2 x 2). This pt had minimal post BMT toxicity, and is engrafted with 100% donor cells at 1 year post BMT. In summary, the combination of high dose BU and FLU for pts with high risk HGBpathies was well tolerated and induced full engraftment for pts with Thal, but mixed chimerism for pts with SCD. Nevertheless, all pts so treated survive with normal hematologic function. The addition of melphalan to BU FLU was also well tolerated and could be beneficial in attaining complete myeloablation and full chimerism in pts with SCD.

Description: Key Points The genetic cause of SCID impacts on survival and immune reconstitution and should be considered in tailoring HCT for individual patients. Total and naive CD4+ cell counts in SCID patients 6 and 12 months post-HCT predict long-term survival and sustained immune reconstitution.

Description: T cells can be genetically modified to target tumor antigens through the expression of a chimeric antigen receptor (CAR). CAR T cells targeting the CD19 antigen is a novel therapeutic approach for patients with relapsed B cell acute lymphoblastic leukemia (B-ALL). We have previously demonstrated that CAR T cells have a significant clinical benefit in adult patients with relapsed B-ALL. The primary objective of this study (NCT01860937) is to extend the use and test the safety of CD19 specific CAR T cells in a multicenter trial for children and young adults with relapsed CD19+ B-ALL. To date, 24 patients with very high risk (VHR) or relapsed B-ALL have been enrolled on protocol with a median age of 12 years (range 2-20 years) at time of T cell collection. We have treated 9 patients with relapsed B-ALL with a median age 15 years (range 3-22 years) using patient derived T cells expressing a CD19 specific CAR (19-28z). Patients received a dose of 1-3 x 10^6 CAR T cells/kg and complete response (complete remission or complete remission with incomplete count recovery) occurred in 5/9 (55%) patients. Significantly, correlations with response included lower disease burden (as assessed by bone marrow cellularity; p20 fold), Flt-3L (〉55 fold), IL-5 (〉15 fold), IL-6 (〉100 fold), and IL-10 (〉15 fold) were demonstrated in patients with CRS. Monitoring of bone marrow demonstrated peak 19-28z CAR T cell detection within 1-2 weeks following infusion with gradual contracture over 1-2 months. These early results demonstrate the feasibility and significant clinical impact of this approach in patients with relapsed B-ALL. In an effort to more rapidly generate statistically relevant data, demonstrate the "exportability" of this technology between academic institutions, and offer this therapeutic option to a broader number of pediatric patients with chemo-refractory B-ALL we have expanded this trial to include a collaborating institution. The objective of our trial is not to provide an intent-to-treat cohort, but rather demonstrate the tolerability of this technology in patients with relapsed B-ALL. Furthermore, patients meeting disease eligibility were not pre-screened for lymphocyte function prior to collection and/or treatment. Subsequent cohorts of patients will receive 19-28z CAR T cells and will be evaluated for toxicity, persistence of CAR T cells, and for anti-leukemic efficacy. Disclosures Curran: Juno Therapeutics: Consultancy. Off Label Use: CAR T cells for B-ALL. Riviere:Juno Therapeutics: Other: Co-founder, stockholder and consultant. 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.. Park:Actinium Pharmaceuticals, Inc.: Research Funding; Juno Therapeutics: Consultancy. O'Reilly:Atara Biotherapeutics: Research Funding. Sadelain:Juno Therapeutics: Other: Co-founder, stockholder and consultant. Brentjens:Juno Therapeutics: Other: Co-founder, stockholder and consultant.

Description: Background Acute graft-versus-host disease (aGVHD) is common after double-unit cord blood transplantation (CBT) with an incidence of grade II-IV aGVHD as high as 55% by day 180 in patients transplanted without ATG. aGVHD is associated with increased morbidity and transplant-related mortality (TRM). Mycophenolate mofetil (MMF) combined with a calcineurin-inhibitor is commonly used to prevent GVHD after CBT. However, unlike the 1 gram (gm) every 8 hours dosing that is now standard in adult donor allografts, MMF dosing in CBT has traditionally been every 12 hours. Our center has increased MMF dose from 1 gm every 12 (q12) to 1 gm every 8 (q8) hours in an effort to reduce severe aGVHD after double-unit CBT. However, the efficacy of this intervention is not established and a theoretical concern is that intensified MMF dosing could result in an increased risk of delayed engraftment or graft failure. Methods We evaluated 171 double-unit CBT recipients (median age 39 years, range 0.9-71) transplanted with either myeloablative (MA, n = 133) or non-myeloablative (NMA, n = 38) conditioning for high-risk hematologic malignancies between 10/2005 and 4/2013. CB units were 4-6/6 HLA-A, -B antigen, -DRB1 allele matched to the recipient (16 6/6, 171 5/6, 155 4/6). All patients received GVHD prophylaxis with intravenous calcineurin-inhibitor (predominantly CSA) and MMF from day -3 without ATG. Prior to 9/2009, 80 patients (47%) received MMF 1 gm IV q12 (and those 12 years and ≥50 kg (or 15 mg/kg/dose if 〉12 years but

Description: Abstract 3080 As compared to single-unit CBT, DCBT may improve engraftment and protect against relapse. Therefore, we have adopted DCBT for both children and adults with acute leukemia, myelodysplasia (MDS), and myeloproliferative diseases (MPD). However, determinants of disease-free survival (DFS) have yet to be fully established. Furthermore, whether DFS after DCBT is comparable in patients of European and non-European ancestry is of special interest. Therefore, we analyzed the DFS of 75 DCBT recipients with acute leukemia in morphologic remission or aplasia (n = 69), and MDS/MPD with ≤ 5% blasts (n = 6) transplanted from 10/2005-4/2011. Nearly all patients had high-risk disease. Children 0–15 years (n = 23) had the following characteristics: median age 9 years (range 0.9–15); median weight 37 kg (range 7–72); 30% European; and 26% CMV sero-positive. Diagnoses were 43% AML (or biphenotypic), 52% ALL, and 4% MDS/MPD, and all received high-dose conditioning. The children received grafts with a median infused TNC × 107/kg of 3.3 (larger unit) and 2.6 (smaller unit), and 2% of units were 6/6 HLA-A, -B antigen, -DRB1 allele matched, 63% 5/6, and 35% 4/6. Adults ≥ 16 years (n = 52) had the following characteristics: median age 41 years (range 16–69); median weight 69 kg (range 47–105); 48% European; 69% CMV sero-positive; and diagnoses were 63% AML (or biphenotypic), 27% ALL, and 10% MDS/MPD. Fifty percent received high-dose and 50% reduced intensity conditioning. Their units had a median infused TNC/kg of 2.7 and 1.9, and 3% were 6/6 HLA-matched, 47% 5/6, and 50% 4/6. All patients (pediatric and adult) received calcineurin-inhibitor/ mycophenolate mofetil immunosuppression, and none received anti-thymocyte globulin. Sustained donor neutrophil engraftment was seen in 91% of children and 94% of adults at medians of 20 and 26 days, respectively. The incidence of grade II-IV acute GVHD by day 180 was 44% in children and 58% in adults. Day 100 transplant-related mortality (TRM) was 9% in children and 19% in adults. The 2-year relapse incidence was 9% in children and 6% in adults. With a median follow-up of survivors of 26 months (range 4–70), 2-year Kaplan-Meier estimate of DFS was 78% in children and 64% in adults (Figure). Differences in survival by age did not reach significance. Univariate analysis of variables potentially influencing 2-year DFS (with log rank estimates of significance) in all patients is shown in the Table. There were no differences in 2-year DFS according to ancestry, remission status, and conditioning intensity. There was also no difference in 2-year DFS according to engrafting unit-recipient HLA-match (4-6/6 or 10 allele), or engrafting unit infused TNC dose/kg. However, patients who were CMV seronegative had a higher 2-year DFS (85% vs 55%, p = 0.018). Multivariate analysis revealed recipient CMV serostatus was a predictor of DFS independent of patient age, and its effect was mediated by an influence on TRM. We have previously shown that DCBT extends transplant access to minority patients. We now demonstrate that DCBT can achieve high and comparable DFS in both European and non-European pediatric and adult patients with acute leukemia and MDS/MPD. While these are very encouraging results further investigation in racial/ethnic sub-groups is needed. Nonetheless, our findings support DCBT as an immediate alternative therapy for high-risk acute leukemia in patients without suitable unrelated volunteer donors, especially given the very low incidence of relapse. Disclosures: No relevant conflicts of interest to declare.

Description: The risk of developing an EBV-LPD is highest in recipients of an unrelated or HLA-mismatched related TCD HCT, with a reported incidence of 10–23%. Although treatment with anti-B cell monoclonal antibodies and/or adoptive immunotherapy can be curative, these therapies are not always effective and can cause fatal tumor lysis syndrome. We have previously shown that the risk of developing an EBV-LPD after a TCD HCT is greatest within the first 2 to 6 months post HCT, and in patients whose circulating CD4 cell counts are less than 200/ul. We therefore developed a phase I pilot trial to investigate the feasibility of 6 monthly doses of rituximab for the prevention of EBV-LPD. Eligibility included hepatitis B surface antigen negative recipients of a TCD HCT from an unrelated or HLA mismatched related donor, EBV seropositive donor and/or host, ANC of 〉1500 cells/ul, documentation of remission, negative EBV viremia at baseline, and lack of ongoing infection at the time of enrollment. Patients received a maximum of 6 consecutive monthly doses of rituximab (375 mg/m2/dose) starting approximately 1 month post HCT. Less than six monthly doses were given if the patient developed a circulating CD4 cell count 〉 200/ul sooner than 7 months post transplant. To date, 22 patients (4–68 years of age, median 19.5 years) have been enrolled on this IRB approved trial, 20 of whom have completed therapy. Rituximab was well tolerated. The main side effect potentially related to rituximab was reversible neutropenia (n=5), which resulted in cessation of treatment as per protocol after the 2nd (n=1), 3rd (n=1), or 4th (n=1) dose. To date, none of the 22 patients on trial have developed an EBV-LPD compared to 10.1% of patients who received an unrelated or HLA MM-related TCD HCT during the same time interval but did not receive prophylactic rituximab. Although 2 patients had prolonged shedding of parainfluenza virus (n=1) or RSV (n=1) from the upper respiratory tract, there was no significant increase in viral or bacterial infections in patients who received rituximab prophylaxis. No patient on trial developed a fatal infection. Eighteen of 22 patients enrolled on trial are alive at a median of 14.5 months post HCT. One patient died of GVHD and 3 high risk patients succumbed to relapse. In evaluable patients, recovery of normal numbers of circulating B cells occurred between 5 and 12 months after the last dose of rituximab. This trial suggests that monthly rituximab can be safely given during the first 6 months after a TCD HCT, resulting in a decreased incidence of EBV-LPD. Larger trials investigating the optimum number and timing of Rituximab doses required to prevent this complication are needed as are studies evaluating recovery of specific B cell function in recipients of rituximab after allogeneic HCT.

Description: Key Points ST2 is independently associated with aGVHD after day 28 in cord blood transplantation recipients. High ST2 levels predict for increased TRM in cord blood transplantation recipients.