ALBERT

Description: The pediatric immune deficiency X-linked proliferative disease-2 (XLP-2) is a unique disease, with patients presenting with either hemophagocytic lymphohistiocytosis (HLH) or intestinal bowel disease (IBD). Interestingly, XLP-2 patients display high levels of IL-18 in the serum even while in stable condition, presumably through spontaneous inflammasome activation. Recent data suggests that LPS stimulation can trigger inflammasome activation through a TNFR2/TNF/TNFR1 mediated loop in xiap−/− macrophages. Yet, the direct role TNFR2-specific activation plays in the absence of XIAP is unknown. We found TNFR2-specific activation leads to cell death in xiap−/− myeloid cells, particularly in the absence of the RING domain. RIPK1 kinase activity downstream of TNFR2 resulted in a TNF/TNFR1 cell death, independent of necroptosis. TNFR2-specific activation leads to a similar inflammatory NF-kB driven transcriptional profile as TNFR1 activation with the exception of upregulation of NLRP3 and caspase-11. Activation and upregulation of the canonical inflammasome upon loss of XIAP was mediated by RIPK1 kinase activity and ROS production. While both the inhibition of RIPK1 kinase activity and ROS production reduced cell death, as well as release of IL-1β, the release of IL-18 was not reduced to basal levels. This study supports targeting TNFR2 specifically to reduce IL-18 release in XLP-2 patients and to reduce priming of the inflammasome components.

Description: Introduction: Polycythemia vera (PV) is a myeloproliferative neoplasm (MPN) characterized by expansion of the granulocytic, erythrocytic, and megakaryocytic lineages in the bone marrow and peripheral blood, and in most cases, by the presence of a JAK2 mutation. Survival of patients with PV is decreased compared with age-matched controls, and this is mainly due to thromboembolic complications followed by progression to post-PV myelofibrosis and acute leukemia. While no curative treatment exists, cytoreductive treatment with hydroxyurea (HU) or ropeginterferon is approved in EU for first-line therapy, and ruxolitinib (RUX) is approved in EU and US for second-line therapy in patients with HU intolerance or resistance. The current futility analysis assesses the efficacy of ruxolitinib in newly-diagnosed PV treated within the Ruxo-BEAT trial. Methods: This clinical trial entitled "Ruxolitinib versus Best Available Therapy in patients with high-risk Polycythemia Vera or high-risk Essential Thrombocythemia" (Ruxo-BEAT; NCT02577926) is a multicenter, open-label, two-arm phase-IIb trial with a target population of 380 pts with PV and ET. Patients in first-line PV and in first and later lines ET are randomized in a 1:1 manner to receive either RUX or best available therapy (BAT). Crossover from BAT to RUX is possible in eligible patients after 6 months. Patients with PV in the RUX arm receive a starting dose of 10 mg bid and may increase their dose up to 20 mg bid. Primary endpoint is the rate of complete clinicohematologic response rate (CHR) at month 6 as defined by Barosi et al Blood 2009. Secondary endpoints include differences in the absence of phlebotomies, spleen size, patient-reported outcomes, and survival. This is a pre-specified futility analysis of RUX in the PV arm, after 50 PV patients had been enrolled. Of the 50 patients, 28 patients with newly-diagnosed PV were randomized into the RUX arm and were analyzed (a maximum of 6 weeks of HU, anagrelide, or interferon therapy was allowed). The PV arm would have to be closed if no favorable trend were observed for RUX for any of the following variables: (1) improvement (decrease) in the hematocrit level during 6 months of treatment, (2) improvement (decrease) of the JAK2V617F allele burden during 6 months of treatment, or (3) improvement of one of the following three symptom variables assessed by physician´s judgement or via MPN Symptom Assessment Form (MPN-SAF) during 6 months of treatment: pruritus, night sweats, or bone pain. Differences between screening (Hct) or baseline (all other variables) and end of month 6 (all variables) were calculated using Fisher´s exact test (for physician-assessed pruritus and night sweats) or the Wilcoxon matched-pairs signed rank test (all other variables). Results: 28 patients received RUX for at least 6 months. After 6 months, the mean hematocrit level decreased from 45.9+/-5.6% to 41.0+/-5.0% (mean+/-SD) (p=0.0003). The number of phlebotomies calculated per year decreased from 4.2+/-3.9% to 0.96+/-2.1 (p=0.0009). Mean JAK2V617F allele burden decreased from 50.2+/28.4% to 44.0+/-28.5% (p=0.0039). The percentage of patients, as assessed by the physician, with pruritus or night sweats decreased from 41% to 26% (trending with p=0.13), and from 30% to 11% (p=0.02), respectively. The points reported by patients themselves on the MPN-SAF survey for pruritus decreased from 2.7+/-3.0 to 1.3+/-1.5 (p=0.0095) and there was a strong trend for reduction of night sweat points (from 3.1+/-3.6 to 1.6+/-2.4; p=0.0579), while the points for bone pain remained unaltered (2.0+/-2.8 to 1.4+/-2.2; p=0.215). Conclusion: Treatment with ruxolitinib in first line PV is efficient regarding the above-mentioned endpoints. Recruitment of our trial will be ongoing. In order not to weaken the study´s statistical power, comparison of both arms was not performed. Disclosures Koschmieder: Ariad: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol Myers-Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Shire: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis Foundation: Research Funding; CTI: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; AOP Pharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Isfort:Mundipharma: Other: Travel reimbursement; Amgen: Other: Travel reimbursement; Hexal: Other: Travel reimbursement; BMS: Honoraria; Ariad: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria, Other: Travel reimbursement; Novartis: Consultancy, Honoraria, Other: Travel reimbursement; Roche: Other: Travel reimbursement; Alexion: Other: Travel reimbursement. Schafhausen:Novartis: Consultancy, Honoraria; Incyte: Consultancy, Equity Ownership, Honoraria. Griesshammer:Novartis: Consultancy, Honoraria, Speakers Bureau. Platzbecker:Abbvie: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding. Döhner:CTI Biopharma: Consultancy, Honoraria; Daiichi: Honoraria; Jazz: Honoraria; Novartis: Honoraria; Celgene: Honoraria; Janssen: Honoraria. Jost:Abbvie: Consultancy, Patents & Royalties: Royalty payments for the drug compound ABT-199, Research Funding; Bohringer: Consultancy, Research Funding; BMS: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Pfizer: Consultancy, Speakers Bureau; Celgene: Other: Travel Support; Novartis: Research Funding. von Bubnoff:Novartis: Research Funding. Stegelmann:Novartis: Consultancy, Honoraria; Incyte: Consultancy, Honoraria. Crysandt:Amgem: Other: travel grant; celgene: Other: travel grant; Pfizer: Other: travel grant; Gilead: Other: travel grant; Incyte: Membership on an entity's Board of Directors or advisory committees. Gezer:AMGEM: Membership on an entity's Board of Directors or advisory committees. Brümmendorf:Merck: Consultancy; Pfizer: Consultancy, Research Funding; University Hospital of the RWTH Aachen: Employment; Janssen: Consultancy; Ariad: Consultancy; Novartis: Consultancy, Research Funding. OffLabel Disclosure: Ruxolitinib as first-line treatment in newly-diagnosed PV

Description: Key Points cIAPs and XIAP negatively regulate cytokine production, including TNF to disrupt myeloid lineage differentiation. IAPs prevent RIPK1 and RIPK3 activity to limit cytokine production prior to cell death.

Description: Background: Myelofibrosis (MF) is a myeloproliferative neoplasm (MPN) characterized by progressive bone marrow fibrosis, ineffective erythropoiesis, dysplastic megakaryocyte hyperplasia, and extramedullary hematopoiesis. MF includes primary MF (PMF), post-polycythemia vera MF (post-PV-MF), and post-essential thrombocythemia MF (post-ET-MF). Clinical presentation is heterogeneous, marked by splenomegaly, progressive anemia, and constitutional symptoms. The median survival in patients with high-risk disease is approximately 2 years. Hematopoietic Stem Cell Transplant (HSCT) is a potentially curative therapy, however due to considerable morbidity and mortality rates, HSCT is not appropriate for most patients, including elderly patients with intermediate-II and high-risk disease. The Janus kinase (JAK) inhibitor ruxolitinib is approved in the US and EU for the treatment of patients with intermediate or high-risk MF, including PMF, post-PV-MF, and post-ET-MF. In clinical studies, treatment with ruxolitinib has been shown to reduce spleen volume by International Working Group (IWG) criteria in approximately 28% to 42% of patients and improve constitutional symptoms of MF in approximately 46% of patients (Verstovsek, J Hematol Oncol. 2017). Ruxolitinib provides symptomatic improvement, however, does not target the malignant clone or appreciably reduce the degree of fibrosis; some patients experience disease progression and leukemic transformation while on therapy (Versotvsek, NEJM. 2010; Harrison, NEJM. 2012; Kremyanskaya, Br J Hem. 2014). Moreover, ruxolitinib is associated with AEs including anemia and thrombocytopenia, which can lead to discontinuation. Approximately 50% of patients treated with ruxolitinib discontinued treatment within 3 years and 73% at 5 years (Verstovsek, Haematologica. 2015; Verstovsek, J Hematol Oncol. 2017; Cervantes, Blood. 2013; Harrison, Leukemia. 2016). Median overall survival in patients who discontinue ruxolitinib is 14-16 months, highlighting the need for novel therapies targeting alternative pathways in the setting of failure or intolerance of JAK inhibitor therapy (Newberry, Blood. 2017). The tumor suppressor protein p53 is the master regulator of cell-cycle arrest and apoptosis in response to cellular stress or DNA damage. Murine double minute 2 (MDM2) is a key regulator of p53, inhibiting its activity via ubiquitination, nuclear export, and direct inhibition of transcriptional activity. Increased MDM2 protein expression has been observed in MF CD34+ cells, suggesting that MF might be sensitive to MDM2 inhibition (Lu M, Blood. 2017). KRT-232 is a potent and selective, oral, small molecule drug that targets MDM2 and prevents MDM2-mediated p53 inhibition, allowing p53 to mediate tumor cell-cycle arrest and apoptosis. In MF, TP53 is observed to be wild-type in 96% of MF patients, suggesting MDM2 inhibition could be a successful therapeutic strategy in this disease (Raza, Am J Hematol. 2012). KRT-232 has been investigated as monotherapy and in combination with trametinib or dabrafenib in phase I studies of AML and melanoma; the most common treatment-related adverse events (TRAEs) observed were nausea, diarrhea, vomiting, decreased appetite, anemia, leukopenia, thrombocytopenia, and fatigue. The majority of TRAEs were grade 1 or 2. Methods: KRT-232 is being evaluated in an open-label phase 2 study in patients with MF who relapsed on or are refractory to JAK inhibitors (Figure). Up to 247 patients ≥ 18 years of age, with ECOG performance status ≤ 2, with high-, intermediate-2, or intermediate-1 risk disease by Dynamic International Prognostic System (DIPSS), and failure of prior treatment with JAK inhibitors will be enrolled. The study will be conducted in 2 parts. Part A will identify the recommended dose and schedule by testing varying doses and schedules across 7 treatment cohorts. Part B will evaluate safety and efficacy using the recommended dose and schedule from Part A. The primary endpoint of the study is to determine spleen response at week 24; secondary endpoints include improvement in MPN-SAF Total Symptom Score (weeks 24 and 48), red blood cell (RBC) transfusion independence, and rates of complete remission and partial remission (IWG-ERT and ELN) at week 24. This trial is enrolling at multiple sites in the United States and Europe (NCT03662126, EudraCT: 2018-001671-21). Disclosures Garcia-Delgado: Hospital Virgen De La Victoria Malaga: Employment; Novartis: Consultancy, Speakers Bureau; Celgene: Speakers Bureau. McLornan:Jazz Pharmaceuticals: Honoraria, Speakers Bureau; Novartis: Honoraria. Jourdan:Novartis: Honoraria; Astellas: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Al-Ali:Celgene: Research Funding; Novartis: Consultancy, Honoraria, Research Funding; CTI: Honoraria. Pluta:Freelight Poland: Honoraria; Sandoz: Honoraria; Servier: Honoraria; Jansen-Cilag: Honoraria; Novartis: Honoraria; Takeda: Honoraria; Roche: Honoraria; Specialistic Hospital in Brzozow,Dept of Haematooncology Ks.Bielawskiego 18 36-200 Brzozow, Poland: Employment; Teva: Honoraria; Roche Poland: Membership on an entity's Board of Directors or advisory committees; Jansen Cilag Poland: Membership on an entity's Board of Directors or advisory committees. Ewing:Novartis: Honoraria, Other: Meeting attendance sponsorship ; Bristol Myers-Squibb: Other: Meeting attendance sponsorship . Khan:Amgen: Consultancy; Celgene: Consultancy; Incyte: Honoraria; Pfizer: Consultancy; Takeda: Research Funding. Jost:Novartis: Research Funding; Celgene: Other: Travel Support; Pfizer: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Abbvie: Consultancy, Patents & Royalties: Royalty payments for the drug compound ABT-199, Research Funding; Bohringer: Consultancy, Research Funding; BMS: Consultancy, Speakers Bureau. Rothbaum:Kartos Therapeutics: Employment, Patents & Royalties: Pending; Quogue Bioventures LLC: Equity Ownership, Membership on an entity's Board of Directors or advisory committees. McGreivy:Kartos Therapeutics: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Verstovsek:Incyte: Research Funding; Roche: Research Funding; NS Pharma: Research Funding; Celgene: Consultancy, Research Funding; Gilead: Research Funding; Promedior: Research Funding; CTI BioPharma Corp: Research Funding; Genetech: Research Funding; Blueprint Medicines Corp: Research Funding; Novartis: Consultancy, Research Funding; Sierra Oncology: Research Funding; Pharma Essentia: Research Funding; Astrazeneca: Research Funding; Ital Pharma: Research Funding; Protaganist Therapeutics: Research Funding; Constellation: Consultancy; Pragmatist: Consultancy. OffLabel Disclosure: Yes, KRT-232 is an investigational small molecule MDM2 inhibitor. This trial-in-progress abstract describes a registered clinical trial that will evaluate the safety and efficacy of KRT-232 for patients with myelofibrosis.

Description: The ETV6-ABL1 fusion gene, as consequence of a t(9;12)(q34;p13), is a rare but recurrent genetic aberration found in chronic or blast phase of eosinophilia-associated myeloproliferative neoplasms (MPN-eo) and de novo acute B-cell lymphoblastic leukemias (B-ALL) or lymphoblastic T-cell lymphomas (T-LBL). Here, we sought to evaluate a) relevant clinical characteristics, b) treatment options and c) survival in 7 ETV6-ABL1 positive patients (male, n=4; median age 46 years; range 20-61). Cytogenetic analyses revealed a conventional reciprocal translocation t(9;12)(q34;p13) in 3 cases, an ins(12;9)(p13;q34q22) and a normal karyotype in one patient each, and a complex karyotype in 2 patients. In all cases, ETV6-ABL1 was confirmed by FISH analysis and/or RT-PCR. Histopathological diagnoses of the hypercellular bone marrow (BM) included atypical chronic myeloid leukemia (n=3), MPN-eo (n=3, concomitant T-LBL in one patient) or chronic myelomonocytic leukemia (n=1). In peripheral blood, all patients presented with left shifted leukocytosis (median 84 x 109/l, range 21-143) and significant (〉1.5 x 109/l) eosinophilia (median 6.1 x 109/l, range 2.0-7.1) but without increased blast cells. Splenomegaly was present in 60% of patients. After a median of 3 months (range 0-6) from diagnosis, all patients were treated with a TKI (imatinib, n=5; dasatinib, n=1; nilotinib, n=1) at standard doses. On dasatinib (#2) or nilotinib (#3), 2 patients achieved a complete hematologic remission (CHR) within 3 months and complete cytogenetic remission (CCR) after 5 months (#3) or complete molecular remission (CMR) after 18 months (#2), respectively (Figure). On imatinib (n=5), 2 of 5 patients (#4 and #5) achieved a CHR within 3 months with loss of CHR after 9 (#4) and 5 months (#5), respectively. Patient #4 developed a myeloid sarcoma. After local radiation, he received an allogeneic stem cell transplant (SCT) but died 8 months later due to GvHD while in CMR. Patient #5 switched to nilotinib and achieved a CCR and CMR after 3 and 10 months, respectively. Patient #1 has not achieved a significant response after 4 months on imatinib. Patient #6 showed progressive disease within 2 months on imatinib, but achieved a rapid CHR and durable CCR and CMR on dasatinib after 13 and 14 months, respectively. Patient #7 presented with a classical myeloid/lymphoid (T-LBL) neoplasm with eosinophilia (MLN-eo) according to the WHO classification. On imatinib, a regression of lymphadenopathy, but persistence of leukocytosis and eosinophilia was observed. With increasing leukocytosis and reappearance of lymphadenopathy, the patient was switched to dasatinib (9 months), followed by nilotinib (2 months). The responses were only partial and transient and the patient died 23 months after diagnosis with myeloid blast phase (secondary acute myeloid leukemia). Overall, after a median treatment time of 22 months (range, 3-58), 4 patients are in CCR (n=1, patient #3) or CMR (n=3; patients #2, #5, #6) while on a second generation TKI and two patients (#4, #7) have died. On imatinib, none of 5 patients achieved a CCR or CMR. We conclude that a) cytogenetic analysis is an important tool for the identification of potential TK fusion genes such as ETV6-ABL1, b) ETV6-ABL1 is a candidate for incorporation into the WHO-defined subcategory ´MLN-eo´, c) patients with MPN-eo can achieve durable CHR, CCR or CMR on TKI with second generation TKI being more effective than imatinib d) close monitoring by cytogenetics, FISH and RT-PCR is recommended for early identification of inadequate response or resistance. Figure (A) responses and (B) overall survival in 7 patients with ETV6-ABL1 positive MPN-eo treated with various tyrosine kinase inhibitors.Abbreviation, CHR:complete hematologic response; CCR: complete cytogenetic response; CMR: complete molecular response; CP: chronic phase; BP: blast phase; allo SCT: allogeneic stem cell transplantation. Figure. (A) responses and (B) overall survival in 7 patients with ETV6-ABL1 positive MPN-eo treated with various tyrosine kinase inhibitors.Abbreviation, CHR:complete hematologic response; CCR: complete cytogenetic response; CMR: complete molecular response; CP: chronic phase; BP: blast phase; allo SCT: allogeneic stem cell transplantation. Disclosures Somervaille: Novartis: Consultancy, Honoraria; Imago Biosciences: Consultancy. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership.