ALBERT

Description: Background: Graft-versus-host disease (GVHD) is a major complication of allogeneic hematopoietic cell transplantation (HCT). Severe acute GVHD of the gastrointestinal tract can be life threatening and is associated with a loss of acute phase proteins including alpha1-antitrypsin (AAT). AAT acts as a potent anti-inflammatory agent. We and others have shown in allogeneic murine models that administration of AAT during HCT suppresses serum levels of pro-inflammatory cytokines, interferes with GVHD and reduces transplant-related mortality. We embarked upon a phase I/II clinical study to evaluate the feasibility and safety of AAT given to HCT recipients with steroid non-responsive acute GVHD. We aimed at characterizing pharmacodynamic effects of AAT and assess clinical responses as determined by changes in stool volume and overall clinical improvement Methods: Seven patients (3 female, 4 male) with hematologic malignancies were enrolled in the first and second cohort. Patients were 35-59 (median 50.4) years old and were given transplants from HLA-matched siblings (n=5) or received cord blood (n=2) following high intensity (myeloablative) or reduced intensity conditioning with cyclophosphamide +TBI (n=2), Fludarabine+TBI (n=4), or busulfan +cyclophosphamide (n=1). All patients received cyclosporine and MMF for GVHD prophylaxis. Acute GVHD of grades III-IV developed at 49 to 71 (median of 48) days, and treatment with systemic methylprednisolone, 2 mg/kg/day was instituted. Patients showing no clinically satisfactory responses after 5 days were given AAT (GlassiaTM) at 90 mg/kg iv on day 1, followed by 30 mg/kg (first cohort) or 60 mg/kg (second cohort) every other day for a total of 8 doses (15 days). Results: As AAT levels vary considerably from person to person, we determined plasma AAT concentrations before and after administration of exogenous AAT. Pre-treatment AAT levels ranged from 1.25mg/ml to 2.3mg/ml (mean 1.76 mg/ml), while post-treatment AAT levels were 2.5 mg/ml to 5 mg/ml (mean 3.18 mg/ml), i.e. in the normal range. Concurrently, levels of Angptl4, IL10 and IL-15 protein increased in all patients, while TIM-3, a marker of lymphocyte activation, was down-regulated. RQ-PCR analysis of donor-derived cells showed up-regulation of IL-10 and IL-1Ra (50 log2 and 10 log2, respectively, compared to pre-treatment samples). FACS analysis of peripheral blood cells showed a 5-fold increase in CD4+CD24+FoxP3+ Treg cells and a 3 fold increase in CD8+CD205+ dendritic cells (DC) in comparison to pre-treatment samples in all 7 patients. Concurrently, the numbers of TIM-3 expressing CD4+ T lymphocytes decreased. While endoscopic evaluation of patients before treatment revealed severe intestinal GVHD with mucosal denudation, endoscopic evaluation one week after completion of AAT administration showed evidence of re-epithelialization of the bowel wall. Concurrently, five of the seven patients developed formed stools, associated with decreased intestinal loss of AAT. One patient required additional therapy and died with biopsy proven liver GVHD. With a median follow-up of 8 months (range 3.5-12 months), five of of seven patients are alive, no longer requiring treatment for GVHD. Summary and conclusions: Continuous administration of AAT as salvage therapy for steroid resistant gut GVHD is feasible without clinically relevant toxicity. Stool sampling showed a decrease in intestinal AAT loss, as measured by AAT clearance and endoscopic evaluation confirmed healing of the bowel mucosa. These data are encouraging, and further exploration of AAT therapy in extended phase II and randomized trials as therapy of steroid refractory acute GVHD or as first line therapy are warranted. Disclosures Off Label Use: Off label use of Alpha 1 Anti-Trypsin (AAT) as second line therapy for steroid-refractory gut GVHD..

Description: Abstract 522 Graft-versus-host disease (GVHD) is an important complication of allogeneic hematopoietic cell transplantation (HCT). The role of various cell populations, cytokines and chemokines, present pre and post-transplantation, in the development of GVHD has been studied extensively.We investigated the potential role of Interleukin (IL)-32 in alloreactivity and GVHD. IL-32 is the protein product of the NK4 transcript first reported in IL-2 activated T lymphocytes and natural killer cells. IL-32 has pro-inflammatory and pro-apoptotic properties and induces expression of TNF-α in several cell targets. We used one-way mixed lymphocyte cultures (MLC) as a simple in vitro model of GVHD to determine IL-32 expression upon alloactivation. The α and γ isforms of (IL)-32 protein were 2-fold upregulated in allogeneic MLC compared to autologous controls (n=4, p=0.037). Concurrently, the concentrations of TNF-α, IL-6 and IL-8 in the allogeneic MLC supernatants were, as expected, upregulated significantly. This finding led us to evaluate IL-32 expression as a potential marker for GVHD after allogeneic HCT in 45 patients with either active acute GVHD or chronic GVHD, and 16 patients who did not show clinical evidence of GVHD. IL-32 mRNA levels in peripheral blood unsorted white blood cells, correlated with acute GVHD (RT-PCR values expressed as mean +/− SEM of the ratio of expression of IL-32/GUS-B = 1.01, p=0.011, vs control values IL-32/GUS-B = 0.23) but not with chronic GVHD, (IL-32/GUS-B = 0.26, p=0.16) (Figure 1). As the serine protease neutrophil proteinase 3 (PR3) has been shown to serve as activator of IL-32, and to process several inflammatory cytokines, including IL-32, TNF-α and IL-8, we postulated that the addition of the serine protease inhibitor α-1 anti-trypsin (AAT), would interfere with the processing of IL-32 by PR3, and as a result would lead to decreased proliferation of cells in MLC, and reduced cytokine production. To test this hypothesis, MLCs were treated with AAT at concentrations of 1–20 ug/ml and expression of IL-32 and PR3 were determined. In MLCs treated with AAT at the optimal concentration of 5 ug/ml, added to cultures on alternate days for a period of 7 days T lymphocyte proliferation was suppressed when compared to vehicle-treated MLC, (mean CPM=33.000 versus CPM=67.000; p=0.012). Concurrently there was a 2.5 fold decrease in IL-32 and PR3 protein levels (n=4, p=0.023). CONCLUSION: IL-32 is upregulated in patients with acute GVHD. Determination of IL-32 in patients with suspected GVHD may support the diagnosis and the decision to treat.AAT interferred with T cell activation and the release of cytokines, including IL-32, suggesting that administration of AAT may have therapeutic potential in patients with acute GVHD. Disclosures: No relevant conflicts of interest to declare.

Description: Background:Spleen tyrosine kinase (SYK) is a nonreceptor cytoplasmic tyrosine kinase primarily expressed in cells of hematopoietic lineage. Constitutive activation of SYK in acute myeloid leukemia (AML) has been reported and targeted inhibition of SYK induced differentiation in vitro and demonstrated anti-leukemia activity in AML mouse models. SYK has also been shown to directly phosphorylate the FLT3 receptor, modulating its activation and possibly promoting its role in leukemogenesis. Entospletinib is an orally bioavailable, selective inhibitor of SYK shown to be clinically active in B-cell malignancies. Here we evaluate the combination of entospletinib in patients with untreated AML using a 14-day window phase to assess single-agent activity, then adding standard intensive chemotherapy. Methods: In this phase 1b/2 study (NCT02343939), patients age 18 to 70 years with previously untreated AML, preserved organ function, and ECOG ≤ 2 were eligible to receive dose escalated entospletinib for 14 days as monotherapy (days -14 to 0) followed by combination with daunorubicin 60 mg/m2/d, cycle 1 day 1 to 3, and cytarabine 100 mg/m2/d, cycle 1 day 1 to 7. All patients received entospletinib monotherapy for up to 14 days prior to starting induction. Chemotherapy could be initiated after 5 days of monotherapy (and entospletinib continued for 4+ weeks) in patients with leukemia-related complications necessitating chemotherapy. Patients enrolled to dose level (DL) 0 and DL 1 received entospletinib 200 mg po BID and 400 mg po BID, respectively. Patients with residual disease two weeks after chemotherapy received a second induction cycle identical to the first. Entospletinib was continued without interruption until remission was assessed at count recovery. Results:Twelve patients enrolled with a median age of 54 (range, 18-69) years. Patients were in the following European LeukemiaNet genetic risk groups: favorable (n=1), intermediate I (n=3), intermediate II (n=2), and adverse (n=4), respectively. Three patients were not evaluable for dose limiting toxicity (DLT) assessment and were replaced (due to detection of CNS disease requiring non-study therapy (n=1), and withdrawal of consent unrelated to drug toxicity (n=2)). Single-agent entospletinib during the window period was well tolerated; toxicities after combination with intensive chemotherapy were common and typical. Among 3 patients treated at 200mg BID, no DLT was observed. Of 3 patients treated at 400mg BID, a patient with documented fungal pneumonia developed grade 3 pneumonitis that was possibly related to entospletinib. Although this did not meet DLT criteria, DL 1 was expanded with 3 additional patients, none of whom experienced DLT. Overall, the most common non hematologic adverse events (inclusive of intensive chemotherapy periods) were febrile neutropenia, nausea, and diarrhea. Based on this clinical experience and compiled pharmacokinetic data demonstrating lack of benefit to further dose escalation, 400 mg BID was selected as the recommended phase 2 dose. Responses were seen at both levels. Among the 3 patients treated at 200 mg BID, two required a second induction but all achieved a complete remission (CR) (3/3; 100%). Of the 6 patients treated at 400mg BID, none required a second induction and the CR rate was also 100%. Remarkably, an 18 year old male with 11q23-rearranged AML achieved morphologic and cytogenetic CR after only the 14 day entospletinib monotherapy window (prior to chemotherapy). Another patient with 11q23-rearranged AML had significant platelet response during the window period (this patient refused disease evaluation by marrow aspiration prior to chemotherapy). Conclusions: Entospletinib appears to have significant clinical activity in AML, and its combination at doses up to 400mg BID with intensive chemotherapy is well tolerated. An extended phase 2 program is now underway. Patients with 11q23-rearranged AML may be uniquely sensitive to SYK inhibition by entospletinib. Detailed molecular analysis of these patients is ongoing and will be presented. Disclosures Walker: Gilead Sciences: Research Funding. Bhatnagar:Karyopharm: Research Funding. Marcondes:Gilead Sciences: Employment, Equity Ownership. DiPaolo:Gilead Sciences: Employment, Equity Ownership. Abella-Dominicis:Gilead Sciences: Employment, Equity Ownership.

Description: Background and Hypothesis DNA and histone methylation as well as microRNA (miR) expression are dysregulated in MDS. The histone demethylase KDM2B suppresses let7b, which post-transcriptionally controls EZH2, a histone-lysine N-methyl transferase that methylates lysine 27 on histone 3. We hypothesized that epigenetic dysregulation in MDS involves the KDM2B/ let7b/EZH2 axis (Figure). DZNep (cyclopentanyl analog of 3-deazaadenosine) is a novel compound, which results in loss of lysine27 methylation, re-expression of epigenetically silenced genes, and decreased cell proliferation.We propose that DZNep will bypass cellular dysregulation via the KDM2B/let7b/EZH2 axis and thereby enhance therapeutic efficacy when combined with azanucleosides. Methods CD34+ MDS marrow cells were obtained by density separation and enriched by magnetic-activated cell sorting (MACS; Milteny Biotec, Auburn, CA); purity 95% to 98% by flow cytometry. For NanoString nCounter miR array total cell derived RNA or synthetic miR pools (IDT; 30 pmol per oligonucleotide) were used as input. Nano-string data were validated by real-time polymerase chain reaction (PCR). RNA was extracted using the RNeasy Mini kit (QIAGEN, Valencia, CA). Primers for let7b, U6, KDM2b and EZH2 were synthesized by Applied Biosystems. Total RNA was reverse transcribed with Taqman MiR Reverse Transcriptase kit (Applied Biosystems, Carlsbad, CA). Potential functional roles of KDM2B, let7b and EZH2 were determined in myeloid cell lines MDS-L, PL-21, KG1a,OCI-AML3 and ML1. Conditional knock-down of KDM2B was achieved with 2 short hairpins (open-biosystems). Expression of KDM2B was forced using pCMV-Myc-KDM2B (gift of Dr. Tzatsos) in cell lines with low/absent constitutive levels of KDM2B and high levels of let7b. miRZip plasmids (miRZip anti-sense) were used to knock-down let7b; pre-BAB-let7b (origene) served to overexpress let7b. Gene expression, protein levels and cell proliferation were analyzed by RQ-PCR, western blot and BrdU uptake. To determine the impact of modified let7b and KDM2B expression on treatment responses, MDS-L cells (high constitutive levels of EZH2) were treated with DZNep and methyltransferase inhibitor, 5-azacytidine, and subjected to the same analyses. Results Let7b levels were significantly higher in primary CD34+ MDS marrow cells (n=44) than in healthy controls (p= 0.0304), while KDM2B and EZH2 expression was reduced (n=21, p

Description: Abstract 4142 Background: Injury to healthy (non-target) tissues still is a major limitation of radiation therapy, at least in part related to release of cytokines, including TNFα and IL-1β, which amplify tissue damage. Cytokine release is particularly prominent in patients who receive total body irradiation (TBI) before hematopoietic cell transplantation (HCT), as interactions of allogeneic donor cells with patient tissue contribute to the resulting “cytokine storm” and the development of graft versus-host-disease (GVHD). In murine models, administration of alpha-1 anti-trypsin (AAT) in the peri-transplant period decreased GVHD incidence and mortality. AAT, a member of the serine protease inhibitor (serpin) family, is a major protective protein in the circulation and has been used successfully in the clinic for other indications. Methods: We were interested in determining the potential benefits of AAT in preventing toxicity related to the transplant conditioning regimen, specifically TBI. AAT inhibits proteinase-3 (PR3) which, among other targets, cleaves IL-32 thereby leading to activation of TNFa and enhancing the cytokine storm. Since others have also suggested that AAT, via enhanced expression of heme oxygenase-1 (HMOX-1), leads to activation of Nrf2, thereby enhancing transcription of anti-inflammatory cytokines such as IL10 and the IL-1 receptor antagonist (IL1Ra), we determined the overall shift in the cytokine milieu and cell death. Thus, we irradiated male C3H/HeN mice (n = 5 mice per group; 6–8 weeks old) with sub-lethal doses (500, 600 and 700 cGy) of TBI from a 137Cs source. AAT (300 μg/animal) was administered intra-peritoneally 1 hour before and every 48 hours after TBI for a total of 6 doses. The effect of TBI/AAT on hematopoiesis was analyzed by growing granulocyte-macrophage colony forming units (GM-CFU) from bone marrow cells, on days 3, 7 and 14 after TBI. Results: Results were compared to those with cells from albumin-treated controls. Marrows (days 3 and 7) from AAT-treated mice generated higher GM-CFU counts than those from controls (mean = 25 vs. 5 colonies per 25 × 103 cells plated after 500cGy, and 15 vs. 3 colonies per 25 × 103 cells after 600 cGy). Peripheral blood and unsorted bone marrow from AAT-treated mice showed up-regulation of HMOX-1 and Nrf2 (30 and 50 log2 increase, respectively), and enhanced transcription of IL-10 and IL-1Ra (50 and 10 log2, respectively) compared to albumin treated donors. PR3 and TNFα, in contrast, were down-regulated (5 log2 and 7 log2 decrease in comparison to albumin treated controls). The cytokine mitigating effects of AAT were accompanied by attenuation of ATM-p53-dependent DNA damage responses in bone marrow cells (determined on days 3, 7, and 14), showing a 3-fold decrease in p53 protein levels, and a 6-fold decrease in phospho-ATM in comparison to albumin treated controls (peak day 7). In addition, protein levels of caspase 3 and caspase 9 were decreased (2-fold and 5-fold, respectively; peak on day 7) in unsorted marrow cells and spleen lysates of AAT treated mice in comparison to albumin treated controls. Bone marrow histopathology revealed normo-cellularity and a decrease in cleaved caspase 3 staining in AAT-treated mice compared to albumin treated animals. Summary and conclusions: AAT treatment significantly mitigated the hematopoietic toxicity induced by sub-lethal TBI. The mechanism involves cytokine suppression, associated with attenuation of ATM-p53 mediated DNA damage response. Taken together, these data suggest that AAT treatment pre-TBI provides protection against radiation injury. Disclosures: No relevant conflicts of interest to declare.

Description: The marrow microenvironment contributes to the pathogenesis of ineffective hematopoiesis in Myelodysplastic Syndromes (MDS). Since mutations and cytogenetic alterations seen in the hematopoietic compartment are generally not present in marrow stromal cells, we hypothesized that epigenetic alterations may be responsible for altered stroma function in MDS. To elucidate the epigenome of MDS microenvironment, we used the HELP (HpaII tiny fragment Enrichment by Ligation-mediated PCR) assay to study cytosine methylation patterns of 50,000 CpGs loci covering 14,000 promoters in primary stromal cells. Global DNA methylation of 6 MDS marrow-derived stroma was analyzed by HELP assay and compared to 3 healthy controls. MDS stroma showed aberrant hypermethylation compared with controls (3626 hypermethylated vs 306 hypomethylated loci in untreated MDS stromal cells) that preferentially occurred outside of CpG islands (Test of Proportions, P value

Description: Abstract 1889 Background: Graft-versus-host disease (GVHD) is a frequent complication of allogeneic hematopoietic cell transplantation (HCT). While cytolytic effector function of donor-derived CD8+ cytotoxic T lymphocytes (CTLs) is critical for the elimination of the underlying malignant disease, the goal is to achieve this graft-versus-leukemia (GVL) effect without inducing GVHD. We and others showed in murine models that administration of AAT in the peri-transplant period decreased GVHD incidence and mortality. Concurrently, levels of pro-inflammatory cytokines were suppressed compared to albumin-treated recipients. Since both GVHD and GVL effects are initiated by donor cells, we asked whether donor treatment with AAT would modify GVHD or GVL effects in recipients. Of concern was the observation that AAT enhanced expression of heme oxygenase-1 (HMOX-1) which, via generation of carbon monoxide, enables the transcription factor Nrf2 to bind to the promoters of IL10 and IL1Ra, which might interfere with GVL activity. Methods: We determined the effect of donor AAT treatment on GVHD and GVL in two murine transplant models: C3H/SW(H-2Kbc) into C57Bl/6(H-2Kb) (minor mismatch), and C57Bl/6(H-2Kb) into BALB/C (H-2Kd) (major mismatch). Four regimens of donor and recipient treatment were studied: 1) Donor albumin /recipient albumin; 2) donor albumin/recipient AAT; 3) donor AAT/recipient albumin; 4) donor AAT /recipient AAT. AAT and albumin were given to donors at 3 μg/ dose every 72 hours for two weeks before cell harvesting. Recipients received 3 μ/dose every 72 hours following total body irradiation with 800 cGy. On day 4, recipients were injected with 5 × 106 T cell-depleted bone marrow (TCD-BM) plus 5 × 105 CD4+/CD8+ splenic T cells to induce acute GVHD. To test our hypothesis that donor AAT treatment would interfere with the GVL effect, BALB/C (H-2Kd) recipients were injected i.v. with 20 × 103 A-20 lymphoma cells containing a luciferase reporter construct (A20-luc/yfp; H-2Kd), following TBI. The infusion of TCD-BM and T cells from C57Bl/6(H-2Kb) donors was delayed until day 4 to allow the tumor to home and get established. Results: RT-PCR analysis of donor BM and T cells prior to transplantation showed up-regulation of HMOX-1 and Nrf2 (10 and 15 log2 increase, respectively), and enhanced transcription of IL-10 and IL-1Ra (50 and 10 log2, respectively, compared to albumin treated donors). In contrast, TNFa, was down-regulated (7 log2 decrease in comparison to albumin-treated donors) in both unsorted bone marrow and in CD8+/CD4+spleen cells from AAT pre-treated donors. FACS analysis revealed a 4-fold increase in frequency of CD56+NK cells, and a 5-fold increase in CD4+/CD24+FoxP3+ Treg cells, associated with a 3 fold increase in CD8+/CD205+ APCs/ DC in comparison to albumin treated donors. Mice transplanted with cells from AAT-treated donors showed lower clinical GVHD scores and decreased mortality (Figure 1) in comparison to mice transplanted from albumin-treated donors. BALB/C (H-2Kd) animals transplanted from AAT-treated donors showed significantly lower A-20 tumor signal (luciferase) intensity (over the first 3 weeks post-HCT) than did mice transplanted from albumin-treated donors (n=6, mean 4.8 × 106 (AAT) versus,7 × 106 (albumin) photons/sec/mouse, P =.03). Summary and conclusions: These data suggest that pre-transplant in vivo AAT exposure of donor cells results in protection against acute GVHD. Tumor growth was not increased in mice transplanted from AAT treated donors and, in fact, appeared to be suppressed, presumably related to a significant increase in NK cells. Further studies on donor pre-treatment or direct administration of AAT to the transplant recipients are warranted. Disclosures: No relevant conflicts of interest to declare.

Description: The bone marrow microenvironment provides essential signals for the fate of normal hematopoietic and for leukemic cells. Contact with marrow stroma, which is part of the microenvironment, is generally thought to convey anti-apoptotic signals to (clonal) leukemia cells. Patients with low-grade myelodysplastic syndrome (MDS) early in the disease course show high rates of apoptosis in normal and clonal marrow cells, mediated by tumor necrosis factor alpha (TNFα) and other cytokines. As MDS advances and evolves to leukemia, clonal cells tend to become apoptosis resistant. We showed previously that the leukemia-derived cell line KG1a was resistant to TNFα-mediated apoptosis, but TNFα did induce caspase-3 activation and apoptosis in KG1a cells when co-cultured with the human marrow stroma cell line HS5 (derived from healthy marrow). Apoptosis was contact dependent and required expression of TNF receptor 1 on KG1a cells. Identical results were obtained in co-cultures with primary stroma cells. Gene expression profiling of KG1a cells showed that stroma contact resulted in significant upregulation of genes involved in apoptosis, including PYCARD and p53. To further dissect the relevant signaling pathways, we used a PhosphoScan proteomic LC-MS (Liquid chromatography-mass spectrometry) method to identify proteins that were phosphorylated in response to stroma contact. In parallel to KG1a we examined the parent cell line KG1, which is sensitive to TNFα mediated apoptosis. We determined the phosphorylation sites in proteins within the leukemic cell lines using MS2 and MS3 scans. Database searches were performed with X! Tandem and Mascot and results analyzed by PeptideProphet using data from a synthetic doubly-phosphorylated peptide as control. In KG1a cells cultured without stroma support, the peptide DJ-1/Park-7 was highly phosphorylated, and expression of p53 was inhibited as indicated by decreased levels of p53 mRNA and protein. In co-culture with stroma, KG1a cells expressed higher levels of p53 protein, and levels of phosphorylated DJ-1/ Park-7 were undetectable over a time course of 30 min to 24 hours. In apoptosis-sensitive KG1 cells constitutive DJ-1/Park-7 phosphorylation (in the absence of stroma contact) was undetectable, and p53 was expressed at higher levels than in KG1a cells, consistent with the observed activation of caspase-3 and induction of apoptosis in KG1 cells. Taken together, these data suggest that phosphorylation of DJ-1/Park-7, originally identified as an oncogene product involved in cellular transformation, oxidative stress responses, and transcriptional regulation, was associated with repression of p53 and resistance to TNFα-mediated apoptosis. The relevance of DJ-1/Park-7 (and other genes identified by the PhosphoScan proteomic method) in primary MDS cells is currently being investigated at the molecular and functional levels.