ALBERT

Description: Abstract 347 Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative treatment for many hematologic malignancies or hematopoietic dysfunction syndromes, but the application is still limited due to major complications, such as severe graft versus host disease (GvHD) and infectious complications. Diagnosis GvHD is based on clinical features and biopsies, a non invasive, unbiased laboratory test does not exist. To date the proteomic pattern specific for aGvHD was evaluated blindly on 961 samples collected from 345 patients undergoing allo-HSCT at MHH and 7 additional clinics, including the University of Michigan. The majority of the patients included were transplanted for hematological malignancies (n=329), 16 for hematopoietic failure syndromes, mainly severe aplastic anemia. Conditioning regimens included dose reduced conditioning regimens (FLAMSA and ClaraC for the majority of the patients of MHH), as well as standard conditioning regimens (TBI+Cy or Busulfan+Cy) for about 35% of the patients. GvHD-prophylaxis was cyclosporine A (CSA) and mycophenolate (MMF) or CSA metothrexate (MTX) as appropriate. In addition, about 80% percent of the patients received ATG (antithymocyte globulin) prior to HSCT. A peptide pattern of 31 peptides - either absent/decreased (15) or present /increased (16) - was previously published (Weissinger et al. 2007). Prospective and blinded evaluation of the patients included in this diagnostic analysis for early recognition of patients at risk for aGvHD development revealed the correct classification of patients developing aGvHD about 7 days prior to the development of clinical symptoms for aGVHD with a sensitivity 76% and specificity of about 85% (fig.1). Additional data obtained from patients transplanted until September 2009 will be reported. Based on these data a pre-emptive therapy multicenter trial, administering steroids upon positivity of the proteomic pattern has been initiated now in 10 German centers, testing the efficacy of the pre-emptive therapy on incidence and severity of aGvHD and a possible benefit on overall survival of the patients. Disclosures: Krons: mosaiques-diagnostics GmbH: Employment. Metzger:mosaiques-diagnostics GmbH: Employment.

Description: Introduction: Since the seminal paper of LeBlanc in 2008, despite several negative studies, the scientific community has retained optimism with respect to the usefulness of mesenchymal stroma cells (MSCs) in refractory acute graft-versus-host disease (GvHD). A prevailing theme of past studies was that, while pediatric GvHD responded to MSCs, adult GvHD did not. As reported, we developed proprietary protocols GMP-quality MSC production from bone marrow (BM) mononuclear cells expanded in platelet lysate-enriched media. Patients and Methods: We present treatment data with MSC-FFM for 61 children/adolescents and 31 adults with either "only" steroid-refractory (SR) GvHD (27%) or GvHD which had additionally proven refractory to up to five additional lines of therapy (MR-GvHD) (73%). Pediatric patients tended to have more MR-GvHD than adults. Patients from 23 centers in 6 countries were included. Most patients had severe GvHD (37% °III, 59% °IV, Glucksberg scale). 31 patients (34%) were female,61 male (66%). 69 have a malignant disease (75%), and 23 a non-malignant (25%) disease as indication for transplantation. Donors were MSD (n=21, 23%), MUD (n=56, 61%), haploidentical (n=14, 15%), and 1 MMUD (1%). Patients received myeloablative conditioning with TBI-, Treosulfan-, Busulfan- and Fludarabine-based regimen, with serotherapy, mostly ATG. 89% of patients had had immunosuppression for GvHD prophylaxis, 13% CSA alone, 49% CSA+MTX or MMF; or others (n=15, 16%). Median onset of aGvHD was at 40 days (range: 6-280 d), another 28 days (range: 5-380) until the first infusion of MSC-FFM. Recommended dose and interval is 4 weekly doses of 1-2M MSC/kg body weight; the average patient received only 3 doses, the interval approximately staggered as recommended, with a median dose of 1.4M MSC/kg. Any reduction in GvHD activity by at least one full grade was classified as a partial (PR), absence of any degree of GvHD as a complete response (CR). Results: Day-28 response rates were 84%/25%/59% overall (OR)/CR/PR for children and 80%/35%/45% for adults resulting in a day-28 response rate for the entire cohort: 82%/28%/54%). At last follow-up (LFU) many of the pediatric responders had continued to improve from partial to complete response to response rates of 84%/59%/25% OR/CR/PR, in adults responses were largely unchanged (77%/35%/42%; LFU for the entire cohort: 81%/51%/30%). GvHD °III and °IV were equally likely to respond or resolve. Looking at response rates of SR- vs. MR-GvHD, of the SR-GvHD 96% responded (MR-GvHD: 81%), as well as early and LFU responses in SR-GvHD were more likely to be complete responses (60% and 72% for SR-GvHD, 16% and 43% for MR-GvHD, day-28 and LFU, respectively). Day-28-response was highly predictive of long-term responsiveness, in that only one non-responder on day 28 achieved a response long term, and only two initial partial responders' GvHD relapsed to the same degree of severity as before MSC treatment. The historical expected survival probability for patients with steroid-refractory severe GvHD being in the order of 20% at 6 months. The patients reported here with °III or °IV aGVHD achieved 6-month overall survival probabilities of 65% and 61%, respectively. In total 6 patients relapsed and died (of note: only 69 patients were at risk), 28 deaths were treatment-related. 6-month overall survival rates for children and adults were 68% and 54%, respectively (n.s.). In terms of adverse reactions to MSC-FFM, one case each of spontaneously remitting headache and nausea/vomiting were reported shortly after infusion of the thawed cells. Both events occurred in children and were possibly related to the rapid infusion of DMSO-containing ice-cold fluid and not the active substance. Conclusion: MSC-FFM emanates as a highly efficacious treatment for severe pediatric and adult advanced GvHD, with OR in excess of 80% and survival rates approximating those of patients without GvHD. The very low relapse mortality may suggest that severe GvHD effectively suppresses leukemic recurrence. Better and faster responses of SR- vs. MR-GvHD make a case for early treatment with MSC-FFM. Disclosures Bader: Medac: Patents & Royalties, Research Funding; Cellgene: Consultancy; Neovii: Research Funding; Riemser: Research Funding; Novartis: Consultancy, Speakers Bureau. Kuci:Medac: Patents & Royalties. Kuci:Medac: Patents & Royalties. Bug:Amgen: Honoraria; Jazz Pharmaceuticals: Other: Travel Grant; Neovii: Other: Travel Grant; Astellas Pharma: Other: Travel Grant; Janssen: Other: Travel Grant; Celgene: Honoraria; Novartis Pharma: Honoraria, Research Funding. Lang:Miltenyi Biotec: Patents & Royalties, Research Funding. Sykora:Aventis-Behring: Research Funding; medac: Research Funding. Seifried:Medac: Other: BSD owns IP and is contract manufacturer; Uniqure BV: Research Funding. Bonig:Kiadis Pharma: Consultancy.

Description: Introduction: The combination treatment of venetoclax (VEN) with both low-dose cytarabine (LDAC) and hypomethylating agents (HMA) in untreated primarily elderly AML patients yielded promising response rates leading to its approval for newly diagnosed AML patients who are 75 years or older, or who have comorbidities that preclude use of intensive induction chemotherapy. Prolonged cytopenias are of potential concern in venetoclax treated patients, especially in patients who underwent allogeneic hematopoietic cell transplantation (alloHCT) prior venetoclax treatment. Objective: To compare hematologic recovery in patients treated with VEN in combination with intensive and non-intensive chemotherapy regimens for the treatment of relapsed or refractory (R/R) acute myeloid leukemia (AML) depending on the pretreatment status for alloHCT. Methods: In this retrospective controlled study (www.clinicaltrials.gov NCT03662724), we included patients aged 18 years or older with R/R acute leukemia previously treated with VEN (days 1-7) combined with intensive salvage chemotherapy (fludarabine, cytarabine, idarubicin - FLAVIDA) or VEN combined with non-intensive regimens, namely HMA or LDAC. Eighty-one patients who were treated with FLA-IDA for R/R AML served as control for the intensively treated patients included in this analysis. Responses were evaluated per revised International Working Group criteria for AML. Main outcome measure was the rate of objective response (complete remission [CR] + CR with incomplete blood count recovery [CRi] + partial remission [PR] + morphologic leukemia-free state (MLFS; defined as less than 5% blasts in an aspirate sample). Safety and efficacy analyses included all patients who received at least one cycle of VEN combination treatment. This study was approved by the local Ethics Review Committee in accordance with the Declaration of Helsinki. Results: Between January 2017 and May 2019 49 patients with a median age of 59 years (range 18-80) received VEN with either FLA-IDA (n=14), HMA (n=31) or LDAC (n=4) and had safety and efficacy outcomes reported. The patient cohort was a high-risk cohort of relapsed (n=24) and refractory (n=25) patients. The analysis included 24 patients (49%) with secondary AML and two patients with biphenotypic acute leukemia (BAL). Twenty-two patients (45%) had received prior alloHCT and 7 (14%) had relapsed

Description: This phase 3, multicenter, open-label study evaluated the efficacy and safety of tipifarnib compared with best supportive care (BSC), including hydroxyurea, as first-line therapy in elderly patients (≥70 years) with newly diagnosed, de novo, or secondary acute myeloid leukemia. A total of 457 patients were enrolled with 24% 80 years of age or older. Tipifarnib 600 mg orally twice a day was administered for the first 21 consecutive days, in 28-day cycles. The primary endpoint was overall survival. The median survival was 107 days for the tipifarnib arm and 109 days for the BSC arm. The hazard ratio (tipifarnib vs BSC) for overall survival was 1.02 (P value by stratified log-rank test, .843). The complete response rate for tipifarnib in this study (8%) was lower than that observed previously, but with a similar median duration of 8 months. The most frequent grade 3 or 4 adverse events were cytopenias in both arms, slightly more infections (39% vs 33%), and febrile neutropenia (16% vs 10%) seen in the tipifarnib arm. The results of this randomized study showed that tipifarnib treatment did not result in an increased survival compared with BSC, including hydroxyurea. This trial was registered at www.clinicaltrials.gov as #NCT00093990.

Description: The neurotrophins (NTs), which include nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), NT-3, NT-4, and NT-6, play a major role in neuronal survival. NTs are unique in that they utilize two different classes of receptors: the TRK (tropomyosin-related kinase) receptor protein tyrosine kinase (TRKA, TRKB, TRKC) and the low affinity NGF receptor (LNGFR=p75NTR). Recently, we and others have obtained evidence for potential involvement of this receptor system in leukemia. In the present study, we demonstrate for the first time expression of the three TRKs on the protein level in blasts from patients with newly diagnosed de novo or secondary acute leukemia. TRK expression was detected by flow cytometry using monoclonal antibodies previously validated on cell lines expressing retrovirally encoded TRK and considered positive if 〉20% of leukemic blasts expressed the respective receptor. 93 adult patients (41 female, 52 male) with a mean age of 53.8 years and diagnosis of AML (87%), ALL (12%), or AUL (1%) were enrolled after informed consent. Positive expression for at least one TRK was found in 55% of the analyzed cases without statistically meaningful differences in expression rate between AML (42/81) and ALL (8/11). Interestingly, while TRKB was expressed alone in blasts, TRKA or TRKC expression always occurred concomitantly with TRKB. In contrast to a previous study, we established a clear correlation of TRK expression pattern and FAB classification. In particular, TRKA expression occurred in 19 of 32 myelo-monocytic/monocytic leukemias (59%) whereas only 5 of 39 non-myelo-monocytic/monocytic leukemias (13%) were positive (p

Description: The translocation t(12;22) involves MN1 and TEL and is rarely found in acute myeloid leukemia (AML). Recently, it has been shown in a mouse model that the fusion protein MN1-TEL can promote growth of primitive hematopoietic progenitor cells (HPCs) and, in cooperation with HOXA9, induce AML. We quantified MN1 expression by real-time reverse transcriptase–polymerase chain reaction (RT-PCR) in 142 adult patients with AML with normal cytogenetics treated uniformly in trial AML-SHG 01/99. AML samples were dichotomized at the median MN1 expression. High MN1 expression was significantly correlated with unmutated NPM1 (P 〈 .001), poor response to the first course of induction treatment (P = .02), a higher relapse rate (P = .03), and shorter relapse-free (P = .002) and overall survivals (P = .03). In multivariate analysis, MN1 expression was an independent prognostic marker (P = .02) in addition to age and Eastern Cooperative Oncology Group (ECOG) performance status. Excluding patients with NPM1mutated/FLT3ITDnegative, high MN1 expression was associated with shorter relapse-free survival (P = .057). MN1 was highly expressed in some patients with acute lymphoblastic but not chronic lymphocytic or myeloid leukemia. MN1 was highly expressed in HPCs compared with differentiated cells and was down-regulated during in vitro differentiation of CD34+ cells, suggesting a functional role in HPCs. In conclusion, our data suggest MN1 overexpression as a new prognostic marker in AML with normal cytogenetics.

Description: Abstract 3795 Introduction: Virus-associated hemophagocytic syndrome (VAHS) is a severe complication of various viral infections often resulting in multiple organ failure syndrome and death. Based on previous experience with seasonal (H3N2) and avian (H5N1) infections the 2009 influenza A (H1N1) virus offers the potency of VAHS-development resulting in an aggressive and life-threatening disease. Most patients infected by the novel human influenza A (H1N1) experienced a mild clinical course; however some patients become critically ill with respiratory failure requiring intensive care and ventilator support. Multiple organ failure was one of the leading causes of death suggesting that patients with severe influenza A (H1N1) infection may develop a virus-associated hemophagocytic syndrome (VAHS). Methods: To evaluate frequency, clinical course and outcome of VAHS in critically ill patients a prospective observational study was performed at a single center intensive care unit in Hannover, Germany. Collected data include demographics, comorbid conditions, viral shedding, diagnosis of VAHS, illness progression, treatments and survival. VAHS was suspected when patients developed fever, cytopenia affecting at least two lineages, hepatitis or splenomegaly, hemophagocytosis in bone marrow samples and/or increased serum levels of sIL-2R and ferritin. Diagnosis of VAHS was made according to established HLH-diagnostic criteria. Primary outcome variables were the development of VAHS and VAHS-associated mortality. Results: Between October 5, 2009 and January 4, 2010 twenty five consecutive critically ill patients with RT-PCR confirmed 2009 influenza A (H1N1) infection and respiratory failure were identified. VAHS developed in nine out of 25 (36%) patients. Treatment of VAHS was started in 6 out of the 9 patients; three patients showed terminal disease and were no longer considered candidates for treatment with etoposide and dexamethasone. Despite VAHS-directed therapy, 5 out of the 6 patients died from uncontrolled progress leading to multiorgan failure. Overall, 8 out of the nine patients (89%) with confirmed VAHS died. In contrast, the mortality rate in the remaining 16 patients without VAHS was 25% (p=0.004). Patients were young (median, 45 [IQR, 35–56] years), however 18 (72%) presented one or more risk factors for a severe course of influenza illness. All 25 patients received mechanical ventilation for severe acute respiratory distress syndrome and refractory hypoxemia with duration of mechanical ventilation of median (IQR) 19 (13-26) days. Additionally 17 patients (68%) required extracorporeal membrane oxygenation for median (IQR) 10 (6-19) days. Oseltamivir and zanamivir were used as antiviral treatment in 24 patients (96%) for a median (IQR) of 7 (4-10) days and in 15 patients (60%) for a median (IQR) of 7 (5-12) days, respectively. The median (IQR) duration of viral shedding from disease-onset to the last positive H1N1 RT-PCR was 19 (14-26) days. In patients without VAHS the median (IQR) viral shedding time was 15 (12-22) days as opposed to 21 (14-26) days (p=0.13) in patients with VAHS. Conclusion: The present case series confirms previous post mortem analysis that severe influenza A (H1N1) infection is an important contributor to the development of VAHS in critically ill patients. Development of VAHS was associated with fatal outcome showing rapid clinical deterioration and multi organ failure syndrome and either contributes greatly to, or is itself causative of death in this patient population. Our findings are preliminary but potentially have important implications for future management of patients with influenza A (H1N1) disease as well as other severe virus infections which can induce secondary hemophagocytic syndromes. Disclosures: No relevant conflicts of interest to declare.

Description: Neurotrophins (NTs) and their receptors play a key role in neurogenesis and survival. The TRK (tropomyosin-related kinase) receptor protein tyrosine kinases (TRKA, TRKB, TRKC) are high-affinity NT receptors that are expressed in a variety of human tissues. Their role in normal and malignant hematopoiesis is poorly understood. In a prospective study involving 94 adult patients we demonstrate for the first time cell-surface expression of the 3 TRKs and constitutive activation in blasts from patients with de novo or secondary acute leukemia. At least one TRK was expressed in 55% of the analyzed cases. We establish a clear correlation between the TRK expression pattern and FAB classification. Although only few point mutations were found in TRK sequences by reverse-transcriptase–polymerase chain reaction (RT-PCR), we observed coexpression of BDNF (ligand for TRKB) in more than 50% of TRKB+ cases (16/30). Activation of TRKA or TRKB by NGF and BDNF, respectively, efficiently rescued murine myeloid cells from irradiation-induced apoptosis. Coexpression of TRKB/BDNF or TRKA/NGF in murine hematopoietic cells induced leukemia. Moreover, activation of TRKs was important for survival of both human and murine leukemic cells. Our findings suggest that TRKs play an important role in leukemogenesis and may serve as a new drug target.

Description: (1) Background: Refractory acute graft-versus-host disease (R-aGvHD) remains a leading cause of death after allogeneic stem cell transplantation. Survival rates of 15% after four years are currently achieved; deaths are only in part due to aGvHD itself, but mostly due to adverse effects of R-aGvHD treatment with immunosuppressive agents as these predispose patients to opportunistic infections and loss of graft-versus-leukemia surveillance resulting in relapse. Mesenchymal stromal cells (MSC) from different tissues and those generated by various protocols have been proposed as a remedy for R-aGvHD but the enthusiasm raised by initial reports has not been ubiquitously reproduced. (2) Methods: We previously reported on a unique MSC product, which was generated from pooled bone marrow mononuclear cells of multiple third-party donors. The products showed dose-to-dose equipotency and greater immunosuppressive capacity than individually expanded MSCs from the same donors. This product, MSC-FFM, has entered clinical routine in Germany where it is licensed with a national hospital exemption authorization. We previously reported satisfying initial clinical outcomes, which we are now updating. The data were collected in our post-approval pharmacovigilance program, i.e., this is not a clinical study and the data is high-level and non-monitored. (3) Results: Follow-up for 92 recipients of MSC-FFM was reported, 88 with GvHD ≥°III, one-third only steroid-refractory and two-thirds therapy resistant (refractory to steroids plus ≥2 additional lines of treatment). A median of three doses of MSC-FFM was administered without apparent toxicity. Overall response rates were 82% and 81% at the first and last evaluation, respectively. At six months, the estimated overall survival was 64%, while the cumulative incidence of death from underlying disease was 3%. (4) Conclusions: MSC-FFM promises to be a safe and efficient treatment for severe R-aGvHD.