ALBERT

Description: Key Points Smac mimetic and GCs synergize to induce apoptosis in ALL cells in vitro and in vivo. Smac mimetic and GCs cooperate to deplete IAP proteins and to trigger formation of a RIP1/FADD/caspase-8 complex (ripoptosome).

Description: Key Points We evaluated interference with integrin alpha4–mediated stromal adhesion as a new acute lymphoblastic leukemia treatment. Integrin alpha4 blockade using natalizumab in combination with chemotherapy sensitizes pre-B acute lymphoblastic leukemia to chemotherapy.

Description: Background: The aim of gene therapy is to provide long-term therapeutic effect from a single administration, yet information on response durability is currently limited. AMT-060 is an adeno-associated virus serotype 5 (AAV5) vector with a codon-optimized wildtype human factor IX (FIX) gene and liver-specific promoter. AMT-060 is being analyzed in an ongoing study of 10 participants with severe/moderate-severe hemophilia B (Phase 1/2 study, NCT02396342). Aim: To describe efficacy and safety outcomes from a planned interim analysis at up to 4-years post-AMT-060. Methods: Adult males with FIX activity ≤2% and a severe bleeding phenotype received a single intravenous infusion of AMT-060 (5x1012gc/kg, Cohort 1, n=5) or (2×1013 gc/kg, Cohort 2, n=5). Assessments included FIX activity, FIX replacement use, annualized bleeding rate (ABR), treatment-related adverse events (TRAE), immunological and inflammatory biomarkers up to 4 years (Cohort 1) and 3.5 years (Cohort 2). Results: As of 8 May 2019, for Cohort 1 the mean yearly FIX activity (annualized to 4 years) was 6.0 as compared to 4.4% in the first year, 6.8% in the second year and 7.3% in the third year. Mean yearly FIX activity for Cohort 2 at 3 years was 7.9% as compared to 7.1% in the first year and 8.4% in the second year. Factor IX activity for each patient over the length of follow up is shown in Figure 1. Eight of 9 participants using prophylaxis at baseline were able to discontinue use. During the last 12 months of observation, the mean annualized bleed rate (ABR) was 1.7 for Cohort 1 and 0.7 for Cohort 2. Respectively, these represent a reduction in mean ABR to the year prior to treatment of 88% and 83%. During this same period the consumption of FIX replacement therapy declined 93% and 96% relative to pre-treatment respectively for Cohort 1 and Cohort 2. No participants developed FIX inhibitors or signs of sustained AAV5 capsid-specific T-cell activation. TRAE were mainly reported in the first 3.5-months after treatment, including three participants who experienced transient mild elevations in alanine aminotransferase as previously described. One new TRAE (joint swelling post-exercise) was observed during the last 12 months of observation post-treatment. Updated data, up to 4-years of observation, will be presented for the first time. Conclusions: Long-term stable endogenous FIX activity and reductions in ABR and FIX replacement use were observed following a single treatment with AMT-060. There were no additional safety concerns with longer term follow-up. These findings support the ongoing Phase III study of the enhanced construct, AMT-061, which encodes the highly active Padua FIX variant. Figure 1 Disclosures Miesbach: Bayer, BioMarin, CSL Behring, Chugai, Freeline, Novo Nordisk, Octapharma, Pfizer, Roche, Takeda/Shire, UniQure: Consultancy; Bayer, Novo Nordisk, Octapharma, Pfizer, Takeda/Shire: Research Funding; Bayer, Chugai, Novo Nordisk, Octapharma, Pfizer, Takeda/Shire, UniQure: Speakers Bureau. Meijer:Pfizer, Sanquin, Uniqure: Research Funding; Uniqure, BMS, Aspen, Boehringer Ingelheim, Sanquin, Bayer: Consultancy, Honoraria; Sanquin: Research Funding; Bayer: Research Funding. Coppens:Pfizer: Honoraria; Portola Pharmaceuticals, Inc: Honoraria; Daiichi Sankyo: Honoraria, Research Funding; Uniqure: Research Funding; Boehringer Ingelheim: Research Funding; Sanquin Blood Supply: Research Funding; Bayer: Honoraria, Research Funding; CSL Behring: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria. Kampmann:Uniqure BV: Research Funding. Klamroth:Bayer, Biomarin, CSL Behring, Novo Nordisk, Octapharma, Pfizer, Roche, SOBI, Takeda: Consultancy; Bayer, Novo Nordisk, SOBI: Research Funding. Schutgens:Baxalta Shire, Novo Nordisk, Bayer, CSL Behring, Pfizer, UniQure BV: Research Funding. Castaman:Bayer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sobi: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; CSL Behring: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda (SHIRE): Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kedrion: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Werfen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Research Funding; Uniqure: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Sanofi: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Seifried:Medac: Other: BSD owns IP and is contract manufacturer; Uniqure BV: Research Funding. Schwaeble:Uniqure BV: Research Funding. Bönig:Celgene, Novartis, Sandoz Hexal: Consultancy; Kiadis Pharma: Other: Contract manufacturing of ATIR101; Sandoz Hexal, Uniqure: Research Funding; Miletenyi: Speakers Bureau. Sawyer:Uniqure BV: Employment. Leebeek:CSL Behring: Research Funding; UniQure: Consultancy; Shire/Takeda: Research Funding; Novo Nordisk: Consultancy; Sobi: Other: Travel grant; Shire/Takeda: Consultancy.

Description: We report the first prospective, multi-center, open-label, single-arm phase I/II clinical trial that assesses the safety and feasibility of stem cell transplantation with TCRalpha/beta and CD19-depleted haploidentical grafts generated with the CliniMACS plus System (Miltenyi Biotec, Germany) in combination with a reduced-intensity conditioning in pediatric patients suffering from various malignant and non-malignant diseases (www.clinicaltrialsregister.org; 2011-005562-38). All patients received single agent MMF as short-term GVHD prophylaxis (40mg/kg/day for 30 days). The speed of immune reconstitution was measured in two core labs using standardized methods and the MACSQuant flow cytometry device (Miltenyi Biotec, Germany). Results: Thirty patients from six hospitals were treated (13 female, 17 male; median age 7 years, range 1 - 17 years). Of the 30 recipients, 10 had ALL, 8 had AML, 6 had solid tumors (soft tissue sarcomas and neuroblastomas), 3 had MDS/MPS, and 1 each with lysosomal storage disorder, SCID, and Wiskott Aldrich syndrome. Disease status in acute leukemias/MDS was: CR1 (n=4), relapsed/refractory (n=17). 5/6 patients with solid tumors had relapsed metastatic disease. The conditioning regimen consisted of 15 or 30 mg ATG (Fresenius/Grafalon) or 7 Gy total nodal irradiation, 160 mg/m2 fludarabine, 10 mg/kg thiotepa, and 140 mg/m2 melphalan. The median number of CD34+ cells, TCRalpha/beta+ cells and CD20+ cells infused was 14.6 x 106 (range, 4 - 54.9), 14 x 103 (range, 0.62 - 40.6) and 0.55 x 105 (range, 0.04 - 1.85), respectively. In addition, significant numbers of NK and TCRgd+ cells/kg were infused - 6.67 x 107 (median; range, 0.68 - 18.2) and 1.58 x 107 (median; range, 0.13 - 4.7), respectively. All 30 patients tolerated the infusion of haploidentical stem cell grafts well. Twenty-five patients had primary engraftment of ANC 〉 500 cells/µL at a median of 12 days (range, 10 - 18) and PLT 〉 20,000 cells/µL at a median of 15 days (range, 11 - 27). Peripheral T-cell chimerism at the time of engraftment was completely donor in 19/25 patients (76%), mixed in 3 (12%), and not measured in three. Five patients experienced primary graft failure and 2 had secondary graft failure. All except of one were successfully re-transplanted. None of the recipients developed severe acute GVHD grades III - IV. Only 1 patient had acute GVHD grade II that started on day 22. The vast majority of patients (96.7%) experienced no or only grade I acute GVHD despite minimal GVHD prophylaxis after transplantation. Samples from 24/25 patients with primary engraftment were evaluable for immune reconstitution (Figure 1). On day 28, the majority of WBC were NK cells (median 309 cells/µL; range, 64 - 1026). The second main type of cells were CD3+ cells (median 151 cells/µL; range, 9 - 953), mostly TCRgd+ (median 87 cells/µL; range, 7 - 891). At day 100, TCRab+ cells equalled TCgd+ cells (median 108 vs. 116 cells/µL). B cells recovered more slowly, with a median of 255.5 cells/µL (range, 1 - 1218) on day 63. ADV reactivation contributed most to infectious complications following transplantation. In total, 16/30 patients had ADV DNAemia or were positive in stool. Additionally, seven patients were tested positive for CMV (blood or urine). BK virus was present in 5 patients with 3 patients experiencing cystitis. No EBV reactivation was observed. Two patients had bacterial sepsis, 1 moderate, 1 fatal (due to non-engraftment).No fatal viral infection occurred within 100 days. One molecular relapse was observed within 100 days post transplantation that was treated with blinatumomab. Two of the 30 transplanted patients died within 100 days after transplantation: 1 patient due to sepsis following graft failure (non-relapse mortality) and 1 due to relapse. On day 100, chimerism was completely donor in 20 patients and mixed in two. Conclusions: The CliniMACS depletion system of TCRab+ and CD19+ cells yielded a large number of CD34+ cells, NK cells and TCRgd+ cells, that could be infused safely into pediatric patients with minimal risk of severe acute GVHD. The immune reconstitution was rapid and there was no TRM associated with viral or fungal infections. Coupled with a reduced-intensity regimen, the overall TRM was low. Longer follow up will provide essential information on chronic GVHD and survival outcomes. Figure 1 Immune Reconstitution after transplantation of TCR-alpha/beta and CD19 depleted haploidentical stem cell grafts Figure 1. Immune Reconstitution after transplantation of TCR-alpha/beta and CD19 depleted haploidentical stem cell grafts Disclosures Bader: Riemser: Research Funding; Neovii Biotech: Research Funding; Servier: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Medac: Consultancy, Research Funding. Karitzky:Miltenyi Biotec: Employment. Holtkamp:Miltenyi Biotec: Employment. Siewert:Miltenyi Biotec: Employment. Bönig:Miltenyi Biotec: Consultancy, Honoraria, Research Funding. Handgretinger:Miltenyi Biotec: Patents & Royalties: Co-Patentholder of TcRalpha/beta depletion technology.

Description: Key Points HSP90 inhibition induces apoptosis in BL cells by disrupting tonic BCR signaling. SYK is an HSP90 client protein, and BCR signaling-dependent phosphorylation of HSP90 on Y197 is required for this interaction.

Description: Introduction: The development of gene transfer for hemophilia is advancing rapidly and offers the potential to shift the disease severity from severe to mild with a single treatment. AMT-060 consists of an AAV5 vector with a gene cassette containing an LP1 liver specific promoter and codon-optimized wild type hFIX gene that has previously been shown to result in durable increases in FIX activity of at least 4 years1. This phase 1/2 study aims to investigate the safety and efficacy of AMT-060 in adult patients with severe hemophilia B. Methods: This is a multi-national, multi-center, open-label, dose-escalating study in patients with FIX activity ≤ 2% of normal, and a severe bleeding phenotype. To be eligible, patients had to require either prophylactic exogenous FIX, or on-demand exogenous FIX with more than 4 bleeds per year or suffer from hemophilic arthropathy. Ten patients were treated in two subsequent, escalating dose cohorts, with AMT-060 5x 1012 gc/kg (n=5) or 2x 1013 gc/kg (n=5). Patients received AMT-060 via a single intravenous infusion over 30 minutes. Efficacy assessments include endogenous FIX activity, measured at least 10 days after the most recent administration of exogenous FIX; reduction of exogenous FIX use; and annualized spontaneous bleeding rates. Safety assessments include treatment related adverse events and immunological assessments, including T-cell response to capsid antigens. Results : There were no screen failures for pre-existing antibodies against AAV5. The age of enrolled patients ranged from 33 to 72 years. At enrollment, nine patients were on FIX prophylaxis, and one patient in the high dose cohort used on-demand FIX therapy. At the time of submission, all ten patients have received AMT-060. The mean of all endogenous FIX activity values after cessation of prophylaxis in the low-dose cohort was 5.4% (95% CI 5.0-5.8%, range 3.1-6.7%; n=4), and stable during the 39 weeks of follow-up. Four out of five patients in the low-dose cohort were able to stop FIX prophylaxis. These patients demonstrated a mean reduction in annualized total FIX usage of 82% after treatment with AMT-060. For all five patients in the low-dose cohort, the mean annualized total FIX usage declined 75% after treatment with AMT-060. Following AMT-060 administration, one patient in the lower dose cohort had a mild, asymptomatic, elevation of ALT at week 10 that resolved with a seven weeks course of tapering prednisolone. No change in FIX activity, and no T-cell response or other possibly associated immunogenicity or inflammatory abnormalities were seen during the ALT elevation. Efficacy and safety results will be updated up to 52 weeks of follow up for the low-dose cohort. Initial efficacy and safety results from the higher-dose cohort up to 26 weeks of follow up will also be presented. Conclusions: Follow up of patients with severe hemophilia B who received either the low or higher dose of AMT-060 is ongoing. A single infusion of AMT-060 was generally well-tolerated. FIX activity increased to levels sufficient to provide endogenous prophylaxis in four of five patients in the low-dose cohort, relieving them from the need for exogenous FIX prophylaxis and resulting in marked decrease of FIX usage. 1Nathwani et al. NEJM 2014; 371:1994-2004 Disclosures Leebeek: UniQure: Consultancy; Netherlands Hemophilia Foundation: Research Funding; CSL Behring: Research Funding; Baxter: Research Funding. Tangelder:uniQure: Employment. Meijer:Baxter: Research Funding; Bayer: Honoraria, Research Funding; Pfizer: Research Funding; Sanquin: Honoraria, Research Funding; Boehringer Ingelheim: Honoraria; Bristol-Myers Squibb: Honoraria. Castaman:Novo Nordisk: Membership on an entity's Board of Directors or advisory committees; CSL Behring: Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees; Baxalta-Shire: Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees; Kedrion: Membership on an entity's Board of Directors or advisory committees; Sobi: Membership on an entity's Board of Directors or advisory committees. Cattaneo:Chiesi: Employment. Coppens:Daiichi Sankyo: Consultancy, Honoraria, Research Funding; Boehringer Ingelheim: Consultancy, Honoraria, Research Funding; Bayer: Consultancy, Honoraria, Research Funding; BMS/Pfizer: Consultancy, Honoraria, Research Funding; Sanquin: Consultancy, Honoraria, Research Funding. Klamroth:SOBI: Other: honoraria for advisory boards and speaker fees; uniqure: Other: honoraria for advisory boards and speaker fees; pfizer: Other: honoraria for advisory boards and speaker fees; NovoNordisk: Other: honoraria for advisory boards and speaker fees; Octapharma: Other: honoraria for advisory boards and speaker fees; Baxalta: Other: honoraria for advisory boards and speaker fees ; Bayer: Other: honoraria for advisory boards and speaker fees; Biogen Idec: Other: honoraria for advisory boards and speaker fees; CSL Behring: Other: honoraria for advisory boards and speaker fees. Schutgens:CSL Behring: Research Funding; Sanquin: Research Funding. Hendriks:uniQure: Employment. Corzo:uniQure: Employment. Miesbach:Grifols: Honoraria; CSL Behring: Research Funding; Pfizer: Honoraria; uniQure: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Bayer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; LFB: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Baxalta: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Biotest: Honoraria, Research Funding; Octapharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sobi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novo Nordisk: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

Description: Several single center experiences have shown favorable outcomes using in-vitro depletion of T cell receptor (TCR)-alpha/beta cells and B cells. For the first time we show the manufacturing results of stem cell grafts from haploidentical family donors for 30 pediatric patients with various hematological and non-hematological malignancies and non-malignant diseases within a prospective, multi-center phase I/II clinical trial utilizing the CliniMACS plus System (Miltenyi Biotec, Germany) in combination with a reduced conditioning (www.clinicaltrialsregister.org; 2011-005562-38). The in-vitro T cell depletions of the grafts were performed by four different laboratories under fixed conditions. The grafts were sent to six treatment centers. Methods: Donors received G-CSF for mobilization of stem cells according to local hospital routine followed by leukaphereses that were depleted from TCRab+ and CD19+ cells according to manufacturer's instructions (CliniMACS plus System, Miltenyi Biotec) and as approved by local authorities. For quality purposes the sponsor performed regularly round robin tests to ensure provision of comparable results regarding the residual number of TCRab+ cells in the grafts. The transplants should be composed of a maximum of 7.5 x 108 nucleated cells/mL with targeted ≥ 4 x 106 CD34+ cells/kg, ≤ 25 x 103 TCRab+ cells/kg, ≤ 1 x 105 CD20+ cells/kg and a CD34+ cell viability of ≥ 95%. In case the targeted value for CD34+ cells/kg was not reached, the number of TCRab+ cells/kg was allowed to exceed by up to the four-fold until 4 x 106 CD34+ cells/kg per transplant have been isolated. One transplant could consist of up to three single aphereses depleted of TCRab+ and CD19+ cells. These products were to be infused directly after separation or following cryopreservation. Pooling of aphereses from a single donor was not allowed. Results: 30 pediatric patients, median age 7 years (range, 1 - 17 years) received a total of 43 TCRab/CD19 depleted haploidentical stem cell products. 17 patients got one infusion, 11 two and one patient three infusions. The stem cell products contained in median 9.46 x 106/kg (range, 1.35 - 54.9) CD34+ cells, 8.4 x 103/kg (range, 0.62 - 40.6) TCRab+ cells and 0.32 x 105/kg (range, 0.037 - 1.7) CD20+ cells. Log depletion for TCRab+ cells and B cells was 4.75 (range, 1.2 - 5.33) and 3.43 (range, 0 - 3.93), respectively. In addition significant numbers of NK and TCRgd+ cells/kg were preserved: 3.9 x 107 (median; range, 0.11 - 18.2), 0.67 x 107 (median; range, 0.05 - 4.0), respectively, summing up to a median number of 6.99 x 106(range, 0.42 - 39.7) total CD3+ cells/kg. Viability of CD34+ cells was 97.9% (median, range 91.5 - 100). All patients received transplants (consisting of up to three single consecutive products) with the targeted CD34+ cell dose - median 14.6 x 106 cells/kg (range, 4 - 54.9) and with less than the maximal allowed number of 1x105 TCRab+ cells/kg. Three single products exceeded targeted TCRab cell numbers but remained within the defined limit of the transplant of 1 x 105 cells/kg in order to meet the specification of ≥ 4 x 106 CD34+ cells/kg. In six single products the B cell numbers were above the specified targeted limit (max. 1.7 x 105/kg). Four products had a viability of CD34+ cells between 91.5 and 95%. Of 30 treated patients no patient experienced acute GVHD°III-IV. Only one patient had acute GVHD°II. The transplant of this patient fulfilled the targeted specifications for total CD34+, TCRab+ and CD20+ cells/kg. Round robin tests were performed prior to study start and during the enrollment period. The identified issues were addressed prior to study start and subsequent tests revealed a uniform performance of the manufacturing centers. Conclusion: 43 stem cell products were manufactured and released by 4 manufacturing laboratories for 30 pediatric patients in 6 hospitals within a clinical study investigating TCR alpha/beta and CD19 depleted haploidentical stem cell transplantation after reduced intensity conditioning. A highly effective depletion of TCRab + cells and B cells with comparable results was shown in all laboratories as controlled by frequent evaluation in round robin tests. Limited exceedances of the targeted release criteria of TCRa/b+ cells were acceptable to the physicians and had no clinical impact. Disclosures Bönig: Miltenyi Biotec: Consultancy, Honoraria, Research Funding. Bader:Riemser: Research Funding; Neovii Biotech: Research Funding; Servier: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Medac: Consultancy, Research Funding. Aktas:Miltenyi Biotec: Employment. Dresing:Miltenyi Biotec: Employment. Karitzky:Miltenyi Biotec: Employment. Holtkamp:Miltenyi Biotec: Employment. Handgretinger:Miltenyi Biotec: Patents & Royalties: Co-Patentholder of TcRalpha/beta depletion technology.

Description: The kinetics of HPC engraftment correlate to a significant degree with the efficiency of bone marrow (BM) homing. We recently documented that fresh BM-HPC, rendered SDF-1 unresponsive or Gi-signaling refractory, homed normally, due to efficient retention through α4-integrin/VCAM 1. However, when deletion of α4-integrin or VCAM-1 was combined with SDF-1/CXCR4- or Gi-protein-signaling blockade, BM homing was drastically reduced, uncovering non-dominant contributions of SDF-1/CXCR4 and Gi-proteins. When, in contrast, cytokine (SCF) incubated HPC were transplanted, loss of CXCR4- or Gi-signaling alone significantly reduced BM homing, with little compensation by α4/VCAM-1 and endothelial selectins. These studies depicted a flexible hierarchy of cooperating homing pathways, in which the dominance of the individual pathway contribution is shifted in response to the cytokine milieu. Based on these data, we reasoned that different donor transplant sources might differ in the relative contribution of each homing pathway. This concept was tested with G-CSF mobilized (MPB) and fresh steady-state BM (ssBM) HPC. To assess the homing properties of these two cell sources, we controlled the number of transplanted colony-forming cells (CFU-C). We found that murine or human MPB-HPC homed significantly better than the respective ssBM-HPC: 1.16±0.04% per femur vs. 0.80±0.03% for murine cells, and 1.64±0.13% vs. 0.51±0.04% for human cells transplanted to NOD/SCIDβ2microglobulin −/− recipients were recovered 18h after transplantation (n〉20, p

Description: Introduction: Allogeneic stem cell transplantation (SCT) is an established treatment option for patients with high-risk leukemias. But the success of this approach is still limited by patients’ relapse. Evidence was presented, that minimal residual disease (MRD) status in principle could be treated by donor lymphocyte infusion (DLI). However, T cells within DLI raise the risk for severe graft versus host disease (GvHD). Cytokine-induced killer (CIK) cells, mainly T cells sharing in part characteristics of natural killer (NK) cells, demonstrated potent non major histocompatibility complex (MHC)-restricted cytotoxicity against hematological malignancies, but displayed negligible alloreactivity in vitro and caused minimal GvHD in vivo. Here, we report our single center experience of repetitive, dose-escalating CIK cell infusions in 12 leukemia patients with impending (n=10) or overt relapse (n=2) after allogeneic SCT. Patients and Methods: Between August 11, 2011 and July 31, 2014 CIK cell infusions approved by the regulatory authorities (Regierungspräsidium Darmstadt, Germany) were given repetitively on compassionate used basis to 12 patients (18 years of age, n=1, age 69 years) with haematological malignancies (AML, n=6; ALL, n=5; CML, n=1) and evidence of relapse in the absence of acute GvHD 〉grade I after allogeneic SCT. CIK cells obtained from peripheral blood mononuclear cells of original stem cell donors were generated within 10 days under good manufacturing practice (GMP)-conditions in the presence of interferong, anti-CD3 antibody, interleukin-2 and -15. Results: Altogether 53 CIK cell infusions (median number 3.5, range 1-10 per patient) from matched unrelated (n=6) or haploidentical (n=6) stem cell donors were offered at a minimum of three weeks after allogeneic SCT and an interval of 4-6 weeks between infusions (median follow up after 1st CIK cell infusion 8, range 3-22 months). Patients with overt relapse underwent cytoreductive chemotherapy before infusions. Based on our cumulative experience starting doses of CIK cell infusions were 5x106 CD3+CD56- CIK cells/kg in pediatric and 1x106 CD3+CD56- CIK cells/kg in adult patients. Regardless of donor type, dose escalation continued until a maximal dose of 100x106 CD3+CD56- CIK cells/kg was reached(median dose 10x106, range 0.1-100x106 CD3+CD56- CIK cells/kg). Acute GvHD grade I occurred in two patients after infusions of 1x106 or 5x106 CD3+CD56- CIK cells/kg. Another two patients developed acute GvHD grade III after infusion of 10x106 CD3+CD56-CIK cells/kg, respectively. In 3 patients with relapsed AML CIK cell infusions provided transient remission, but ultimately all three patients relapsed and succumbed to their diseases 8-9 months after first CIK cell infusion. Two patients with ALL and one patient with AML relapsed 2, 5, and 12 months after first CIK cell infusion, respectively. All patients were offered further anti-leukemic treatment including allogeneic SCT. Two AML patients died due to infections 9 and 12 months after the last CIK cell infusion. Both patients were in complete remission at the time of death. Three high-risk patients with ALL and one CML-patient with impending relapse indicated by MRD or BCR/ABL are still in complete remission. Conclusion: In conclusion, allogeneic CIK cell infusions seemed to be very promising and may improve cell-based immune therapies especially in leukemia patients with impending relapse after allogeneic SCT. Disclosures No relevant conflicts of interest to declare.

Description: Introduction ATIR101 is a donor-derived, T-cell-enriched leukocyte preparation depleted ex vivo of host-alloreactive T cells. When administered as a single, adjunctive infusion after T-cell-depleted haploidentical hematopoietic stem cell transplantation (haplo HSCT), ATIR101 may reduce serious complications resulting from delayed immune reconstitution such as infections and relapse. In a Phase II study, patients with hematologic malignancies who received ATIR101 had an overall survival (OS) of 61% and no Grade III/IV acute graft-versus-host disease (GVHD) at 1 year post HSCT (Roy DC et al. ASH 2016). Similarly, an OS rate of 55% was reported in a second Phase II study (Olavarria E et al. EHA 2018). We report multivariable and subgroup analyses of a pooled dataset from these two Phase II studies of ATIR101, compared with a dataset of control patients meeting similar inclusion/exclusion criteria who underwent T-cell-depleted haplo HSCT without ATIR101, to assess the impact of potential prognostic factors on survival outcomes. Methods After showing comparability allowing the pooling of data, 1-year outcomes from two Phase II studies (CR-AIR-007, NCT01794299; CR-AIR-008, NCT02500550; data cut-off June 1, 2018) including 32 adult patients who received ATIR101 (2.0 × 106 cells/kg) were compared with a historic control of 35 patients treated with a T-cell-depleted haplo HSCT without ATIR101 in centers participating in ATIR101 trials (CR-AIR-006, NCT02188290). Patients with a hematologic malignancy (acute myeloid leukemia [AML], acute lymphoblastic leukemia [ALL], or myelodysplastic syndromes [MDS]) underwent myeloablative or reduced-intensity conditioning with or without total body irradiation (TBI) followed by a CD34+-selected stem cell graft from a haploidentical family donor. ATIR101, prepared from the same donor, was given approximately 28 days post HSCT to patients in the ATIR101 group without prophylactic immunosuppression post HSCT. Post hoc multivariable Cox regressions for non-relapse mortality (NRM) and OS were performed on the pooled ATIR101 and control datasets adjusting for treatment, diagnosis, conditioning regimen, remission status, European Society for Blood and Marrow Transplantation risk score, and total number of viable CD34+ (× 106 cells/kg) given to patients. Variables recognized as clinically important were forced into the model regardless of whether they were statistically significant. Results Overall, patient characteristics at baseline were balanced across groups (ATIR101 vs historic control): median age at HSCT (range) was 43 years (31-51) vs 43 years (28-54); patients had AML (66% vs 71%), ALL (28% vs 11%), or MDS (6% vs 17%); patients underwent myeloablative conditioning (100% vs 94%) with TBI (47% vs 66%) and were in complete remission (100% vs 83%) prior to transplantation. The incidence of Grade III/IV acute GVHD was similar in the ATIR101 and control groups (6%); however, only patients in the control group experienced severe chronic GVHD (2/35). Compared with the control group, the ATIR101 group showed a lower cumulative incidence of NRM (28% vs 66%; hazard ratio [HR]: 0.31; 95% confidence interval [95% CI]: 0.15-0.67; p=0.002) and a higher OS rate (63% vs 20%; HR: 0.34; 95% CI: 0.17-0.69; p=0.002). Adjusting for potential prognostic factors, the benefit of ATIR101 was confirmed in a multivariable analysis for both NRM (HR: 0.27; 95% CI: 0.09-0.78; p=0.016) and OS (HR: 0.28; 95% CI: 0.11-0.70; p=0.006; Table). The addition of ATIR101 treatment following T-cell-depleted haplo HSCT improved survival outcomes compared with T-cell-depleted haplo HSCT alone, irrespective of patient baseline characteristics, as shown in the subgroup analyses (Figure). Conclusions A single infusion of ATIR101 after a T-cell-depleted haplo HSCT in patients with hematologic malignancies appears to improve survival outcomes compared with a T-cell-depleted haplo HSCT alone. After adjusting for potential prognostic risk factors, the multivariable analysis appears to support the clinical benefit of ATIR101 on NRM and OS at 1 year post HSCT. A large, global, randomized Phase 3 study is currently enrolling to further examine the efficacy and safety of T-cell-depleted haplo HSCT + ATIR101 compared with T-cell-replete haplo HSCT with post-transplant cyclophosphamide (HATCY; NCT02999854). Disclosures Roy: Hopital Maisonneuve-Rosemont: Patents & Royalties: Author on patent; University of Montreal: Patents & Royalties: Author on patent; Kiadis Pharma: Other: Travel support. Walker:Kiadis Pharma: Other: Grant funding via institution (as a principal investigator). Maertens:Astellas Pharma: Other: Personal fees and non-financial support; Cidara: Other: Personal fees and non-financial support; F2G: Other: Personal fees and non-financial support; Gilead Sciences: Other: Grants, personal fees and non-financial support; Merck: Other: Personal fees and non-financial support; Pfizer: Other: Grant and personal fees; Amplyx: Other: Personal fees and non-financial support. Olavarria:Kiadis Pharma: Consultancy, Honoraria. Selleslag:Novartis: Consultancy, Honoraria, Speakers Bureau; Celyad: Other: Clinical trial research (no honoraria recieved). Wagner:Pfizer: Other: Advisory board; Novartis: Other: Advisory board; MEDAC: Other: Travel support; MSD: Other: Advisory board. Bönig:Kiadis Pharma: Other: Contract manufacturing of ATIR101; Celgene, Novartis, Sandoz Hexal: Consultancy; Sandoz Hexal, Uniqure: Research Funding; Miletenyi: Speakers Bureau. Bos:Celgene: Research Funding; Kiadis Pharma: Other: Shareholder (of Cytosen, acquired by Kiadis). Mielke:ISCT: Other: Travel support; Jazz Pharma: Honoraria, Other: Travel support, Speakers Bureau; DGHO: Other: Travel support.