The CXCL1 Inhibitor Reparixin Rescues Myelofibrosis in the Gata1low Model of the Disease

Abstract A mayor pathobiological role for interleukin 8 in the etiology of myelofibrosis has been suggested by observations indicating that megakaryocytes expanded in culture from these patients express great levels of interleukin 8 1 and that the plasma levels of this cytokine are predictive of poor prognosis 2. In preliminary experiments we demonstrated that the megakaryocytes from the bone marrow of the Gata1 low model of myelofibrosis express not only high levels of TGF-β, but also levels greater than normal of lipokalin-2, a known inducer of IL-8 production, and of CXCL1, the murine equivalent of IL-8. In addition, these megakaryocytes express also high levels of the CXCL1 receptors CXCLR1 and CXCR2 and the bone marrow from these mice express an CXCR1/CXCR2 activated signature. Using these data as a foundation, we tested here the effects of treatment of Gata1 low mice with the CXCR1/R2 inhibitor reparixin on the myelofibrosis phenotype expressed by this models. To these aim, Gata1 low mice (8-month old) were treated either with vehicle (3 males and 3 females) or with reparixin (formerly referred to as repertaxin) 3 (5 males and 5 females) for either 20 or 37 days. The drug was administered by minipumps implanted subcutaneously in the dorsal region set to deliver 7.5mg of drug/hr/Kg of body weight. The mice receiving the drug for 37 days had the minipumps replaced by day 17. The efficiency of drug delivery decreased over time since the plasma levels of reparixin were 13.90±4.18 and 6.71±4.18ug/mL at day 20 and 37, respectively (p<0.05).The drug was well tolerated with no death or change in body weight recorded over the period of observation. Since the results observed in males and females were similar, the data were pooled for statistical analyses. The treatment did not affect blood values (hematocrit (%): 34.32±3.87 vs 35.63±3.45 and 30.92±3.58, platelets: (x10 3/uL) 187.80±26.12 vs 181.30±53.30 and 99.83±71.92 and white cell counts (x10 3/uL): 2.78±0.55 vs 3.27±0.72 and 3.57±1.43, respectively, in vehicle and day 20- or day 37-reparixin treated mice). The treatment had also little effects on bone marrow (20.55±5.83 vs 22.24±0.85 and 21.68±6.49) and on spleen 141.40±29.04 vs 99.54±15.55 and 173.00±76.54) cellularity. However, the bones were reddish and their sections contained great numbers of erythroid cells, a sign of increased hematopoiesis. Great reductions in the fibrosis of the bone marrow and spleen was observed in mice that had been treated with reparixin compared to vehicle which were statistically significant by day 20 (day 20 bone marrow fibrosis 28.09±15.69 in vehicle and 4.54±0.45 in reparixin treated mice by Gomori, p<0.05; 19.30±7.86 vs 3.19±1.89 by reticulin, staining, p<0.05, respectively by Anova; day 20 spleen fibrosis 20.51±5.25 in vehicle and 10.85±3.82 in reparixin treated mice by Gomori, p<0.05; and 13.15±3.06 vs 6.13±2.34 by reticulin, staining, p<0.05, respectively). Of note when the levels of Gomori and reticulin fibrosis detected at day 20 and 37 in individual mice were inversely correlated with the plasma levels of reparixin observed in the same mice (Figure 1, p<0.01-0.05 by Pearson). Mechanistic insights on these results were provided by Immunostaining of marrow and spleen sections of vehicle and reparixin-treated mice indicating that the megakaryocytes from the reparixin-treated group express levels of TGF-β significantly lower than those expressed by the corresponding cells from vehicle while the levels of LCN-2, CXCL1, CXCR1 and CXCR2 expressed by the reparixin treated megakaryocytes are similar to that of the vehicle treated cells. These results indicate that inhibition of CXCL1 by reparixin, probably by reducing the abnormally high TGF-β content of the megakaryocytes, reduces fibrosis in Gata1 low mice and provide a preclinical rational to test this drug in patients with myelofibrosis. References: 1) Emadi S et al. Blood. 2005;105:464; 2) Tefferi et al, J Clin Oncol. 2011;29:1356; 3) Bertini R et al, PNAS 2004; 101:11791 Figure 1 Figure 1. Disclosures Crispino: Forma Therapeutics: Research Funding; Scholar Rock: Research Funding; MPN Research Foundation: Membership on an entity's Board of Directors or advisory committees; Sierra Oncology: Consultancy. Massucci: Dompe Farmaceutici Spa R&D: Current Employment. Brandolini: Dompe farmaceutici Spa R&D: Current Employment. Giorgio: Dompe farmaceutici Spa R&D: Current Employment. Allegretti: Dompe farmaceutici Spa R&D: Current Employment. Migliaccio: Dompe farmaceutici Spa R&D: Other: received funding for reserach .

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Efficacy, Safety, and Confirmation of the Recommended Phase 2 Dose of Ruxolitinib Plus Panobinostat in Patients with Intermediate or High-Risk Myelofibrosis

Blood ◽

10.1182/blood.v124.21.711.711 ◽

2014 ◽

Vol 124 (21) ◽

pp. 711-711 ◽

Cited By ~ 6

Author(s):

Jean-Jacques Kiladjian ◽

Florian H Heidel ◽

Alessandro M. Vannucchi ◽

Vincent Ribrag ◽

Francesco Passamonti ◽

...

Keyword(s):

Bone Marrow ◽

High Risk ◽

Board Of Directors ◽

Research Funding ◽

Phase Iii ◽

Spleen Volume ◽

Bone Marrow Fibrosis ◽

Advisory Committees ◽

Expansion Phase ◽

Marrow Fibrosis

Abstract Background: Myelofibrosis (MF) is a clonal neoplastic disease resulting in bone marrow fibrosis, splenomegaly, and debilitating constitutional symptoms. The Janus kinase (JAK) pathway is often dysregulated in MF, and agents targeting this pathway have demonstrated efficacy in this disease. Ruxolitinib (RUX), a potent JAK1/JAK2 inhibitor, demonstrated superiority in spleen volume reduction, symptom improvement, and survival compared with the control arm in the phase III COMFORT-I and COMFORT-II studies. Panobinostat (PAN), a potent pan-deacetylase inhibitor (pan-DACi), inhibits JAK signaling through disruption of the interaction of JAK2 with the protein chaperone heat shock protein 90. In phase I/II studies, PAN has shown splenomegaly reduction and improvement of bone marrow fibrosis. The combination of RUX and PAN demonstrated synergistic anti-MF activity in preclinical studies. These preliminary results led to the initiation of a phase Ib study evaluating the combination of RUX and PAN in patients (pts) with MF. The updated results from the expansion phase of this trial are presented here. Methods: Eligible pts had intermediate-1, -2, or high-risk primary MF, post-polycythemia vera MF, or post-essential thrombocythemia MF by International Prognostic Scoring System criteria, with palpable splenomegaly (≥ 5 cm below the costal margin). The primary objective was determination of the maximum tolerated dose (MTD) and/or recommended phase II dose (RPIID). Secondary objectives included safety, efficacy, and pharmacokinetics. Exploratory endpoints included assessment of improvement in bone marrow fibrosis and reduction of JAK2 V617F allele burden. The treatment schedule was RUX (5-15 mg) twice daily (bid) every day and PAN (10-25 mg) once daily 3 times per week (tiw; days 2, 4, and 6) every other week (qow) in a 28-day cycle. Following dose escalation and identification of the potential RPIID, additional pts were enrolled into the expansion phase and treated at this dose. Results: As of March 14, 2014, a total of 61 pts were enrolled (38 escalation phase and 23 expansion phase). The median duration of exposure to PAN and to RUX was 24.6 weeks and 24.0 weeks, respectively, for pts treated in the expansion phase. Three DLTs were observed in the escalation phase (grade 4 thrombocytopenia [n = 2], grade 3 nausea [n = 1]). No MTD was reached. The RPIID was confirmed to be RUX 15 mg bid and PAN 25 mg tiw qow in May 2014. Among the 34 pts treated at the RPIID, grade 3/4 adverse events (AEs) regardless of causality included anemia (32%), thrombocytopenia (24%), diarrhea (12%), asthenia (9%), and fatigue (9%). AEs led to discontinuation in 6% of pts treated at the RPIID. Two pts treated at the RPIID died due to causes unrelated to study treatment (1 due to myocardial infarction and 1 due to progression of myelofibrosis). Among the pts treated at the RPIID, 79% showed a >50% decrease in palpable spleen length, with 100% decrease (non-palpable spleen) being observed in 53% of pts. Additionally, 48% of pts treated at the RPIID in the expansion phase achieved ≥35% reduction in spleen volume (Figure). These results are similar to those observed for spleen volume response at 24 weeks among pts who received single-agent RUX on the phase III COMFORT-I (41.9%) and COMFORT-II (32%) studies. Conclusions: The combination of the JAK1/JAK2 inhibitor RUX and the pan-DACi PAN was well tolerated and resulted in high rates of reductions in splenomegaly in pts with intermediate- and high-risk MF. Although a relatively larger proportion of patients experienced spleen volume reductions at week 24 as compared to the COMFORT studies, the smaller sample size, shorter follow up times and potential differences in the patient populations preclude definitive comparisons. Similar to COMFORT-I and II trials, hematological AEs, specifically anemia and thrombocytopenia, were the most common AEs observed in pts treated with the combination therapy. Pts continue to be treated in the expansion phase at the RPIID. Updated safety, efficacy, and exploratory analyses on bone marrow fibrosis, JAK V617F allele burden, and biomarkers, including cytokines, will be presented. Figure Change in Spleen Volume in Expansion Phase Figure. Change in Spleen Volume in Expansion Phase Disclosures Kiladjian: Novartis: Honoraria, Research Funding, Speakers Bureau; Shire: Membership on an entity's Board of Directors or advisory committees; AOP Orphan: Honoraria, Research Funding. Heidel:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees. Vannucchi:Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Ribrag:Celgene: Consultancy; Pharmamar: Consultancy; Epizyme: Research Funding; Bayer: Consultancy, Research Funding; Servier: Consultancy, Honoraria, Research Funding. Conneally:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Honoraria, Speakers Bureau; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Kindler:Novartis: Consultancy. Acharyya:Novartis: Employment. Gopalakrishna:Novartis: Employment. Ide:Novartis: Employment, Equity Ownership. Loechner:Novartis: Employment. Mu:Novartis: Employment. Harrison:Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; Sanofi: Consultancy, Honoraria; CTI: Consultancy, Honoraria; Gilead: Honoraria; SBio: Consultancy; Shire: Speakers Bureau.

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A Phase 2 Study to Evaluate the Efficacy and Safety of Simtuzumab in Adult Subjects with Primary, Post Polycythemia Vera (PV) or Post Essential Thrombocythemia (ET) Myelofibrosis

Blood ◽

10.1182/blood.v126.23.2810.2810 ◽

2015 ◽

Vol 126 (23) ◽

pp. 2810-2810

Author(s):

Srdan Verstovsek ◽

Michael R. Savona ◽

Ruben A. Mesa ◽

Stephen Oh ◽

Hua Dong ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Research Funding ◽

Phase 2 ◽

Fibrosis Score ◽

Bone Marrow Fibrosis ◽

Advisory Committees ◽

Equity Ownership ◽

Stage 1 ◽

Marrow Fibrosis

Abstract Background: Simtuzumab (SIM) is a humanized monoclonal antibody that inhibits lysyl oxidase-like molecule 2 (LOXL2), an extracellular matrix enzyme that catalyzes the covalent cross-linking of collagen and is widely expressed across many fibrotic diseases. In pre-clinical models, inhibition of LOXL2 blocks fibroblast activation, which plays an important role in the development of organ fibrosis. In Phase 1 studies, SIM was well-tolerated in patients (pts) with advanced solid tumors, liver fibrosis, and idiopathic pulmonary fibrosis (IPF). A Phase 2, open-label study to determine the efficacy of SIM alone (Stage 1) and combined with ruxolitinib (rux) (Stage 2) in pts with primary myelofibrosis (PMF) and post-ET/PV MF was initiated. Methods: Eligible pts had intermediate-1, intermediate-2, or high risk disease and Eastern Cooperative Oncology Group performance status of <2. The primary endpoint was rate of clinical response as defined by a reduction in bone marrow fibrosis score following 24 weeks of treatment with SIM. Patients were randomized in a 1:1 ratio to receive 200 mg or 700 mg SIM by intravenous infusion every 2 weeks as monotherapy (Stage 1, n=24) or combined with rux (Stage 2, n=30). Patients received SIM for up to 24 weeks. Bone marrow biopsies and aspirates were performed approximately every 3 months. Bone marrow fibrosis scoring was performed and quantified at local investigator sites using the European Consensus on Grading Bone Marrow Fibrosis. Myelofibrosis symptoms were evaluated using the Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF) and changes in hematologic parameters and splenomegaly were assessed. Results: Between 7/14/11 and 9/22/14, 54 pts were randomized and treated (200 mg SIM [n=12], 700 mg SIM [n=12], 200 mg SIM/rux [n=15], and 700 mg SIM/rux [n=15]). In Stage 1, 0 subjects (0%) in the SIM 200 mg group and 2 subjects (16.7%; 90% CI 3.0%, 43.8%) in the SIM 700 mg group showed a reduction in bone marrow fibrosis score from Baseline to Week 24. In Stage 2, 1 subject (6.7%; 90% CI 0.3%, 27.9%) in the SIM 200 mg/rux group and 2 subjects (13.3%, 90% CI 2.4%, 36.3%) in the SIM 700 mg/rux group showed a reduction in bone marrow fibrosis score from Baseline to Week 24. In an exploratory analysis, similar numbers of subjects showed increases in bone marrow fibrosis scores. SIM treatment was not associated with meaningful improvements in hematologic parameters or reductions in MPN-SAF score or spleen size. The most frequent adverse events were those commonly associated with MF, including constitutional symptoms and reductions in hematological parameters. Conclusions: SIM treatment alone or in combination with rux is safe but does not reliably reduce bone marrow fibrosis in pts with MF. The reason for reduction of marrow fibrosis in some patients and increase in others is unclear and may be sampling variability. Clinical studies of SIM in IPF and liver fibrosis are ongoing. Disclosures Savona: Karyopharm: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; TG Therapeutics: Research Funding; Astex Pharmaceuticals, Inc: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Mesa:Incyte Corporation: Research Funding; CTI Biopharma: Research Funding; Novartis Pharmaceuticals Corporation: Consultancy; Pfizer: Research Funding; Promedior: Research Funding; Genentech: Research Funding; NS Pharma: Research Funding; Gilead: Research Funding. Oh:CTI Biopharma: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees. Dong:Gilead Sciences: Consultancy, Equity Ownership. Thai:Gilead Sciences: Employment, Equity Ownership. Gotlib:Allakos, Inc.: Consultancy.

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Decoding Bone Marrow Fibrosis in Myelodysplastic Syndrome

Blood ◽

10.1182/blood.v128.22.1985.1985 ◽

2016 ◽

Vol 128 (22) ◽

pp. 1985-1985

Author(s):

Megan Melody ◽

Najla H Al Ali ◽

Ling Zhang ◽

Hanadi Ramadan ◽

Eric Padron ◽

...

Keyword(s):

Bone Marrow ◽

Research Funding ◽

Somatic Mutations ◽

Bone Marrow Aspirate ◽

Bone Marrow Fibrosis ◽

Advisory Committees ◽

Significant Difference ◽

Baseline Characteristics ◽

Grade 3 ◽

Severe Fibrosis

Abstract Background Bone marrow fibrosis (BMF) is observed in 10-20% of patients diagnosed with MDS. A study conducted at the University of Pavia, Italy evaluated 180 cases of MDS with varying grades of BMF and found that the presence of grade 2-3 BMF in MDS (graded by European classification) was associated with worse outcomes, especially in patients with lower risk MDS, however there remains little data pertaining to the treatment and outcomes in the MDS-F patient population. The primary objective of this study is to examine a large MDS patient population to further determine the relationship between BMF and survival outcomes in the context of new risk stratification models. Methods All bone marrow aspirate and biopsy reports, obtained at the time of diagnosis or prior to any therapy, in the Moffitt Cancer Center MDS database were reviewed and the degree of BMF was determined using the European classification system. Patients with less than 5% myeloblasts and grade 2 or 3 BMF were identified and these bone marrow aspirate and biopsies were reviewed by two hematopathologists (LZ and JMB) to confirm the grade of fibrosis reported. Patients were then divided into two groups: grade 0-2 BMF and severe BMF (grade 3). These two groups were compared to evaluate differences in clinical characteristics, response to treatment and survival. NexGen sequencing was available for 251 patients and distribution of acquired somatic mutations were compared between grade 0-2 BMF and grade 3 BMF. Results There were 2357 cases included in this analysis of which 2237 (95%) were determined to have grade 0-2 BMF and 120 (5 %) to have grade 3 BMF. Table-1 summarizes baseline characteristics. There was no statistical difference in age at diagnosis, gender, or race. A greater percentage of patients with severe BMF (39%) met the criteria for poor/very poor IPSS-R score category than patients with grade 0-2 BMF (29%), p = 0.011. Complex karyotype was observed more frequently among patients with severe fibrosis (23% versus 15%, p = 0.031). Patients with severe BMF also had a higher incidence of elevated LDH (51%) than patients with grade 0-2 BMF (33%), P < 0.005. The median overall survival (OS) was 38.7 months (mo) for grade 0-2 BMF and 23.1mo for grade 3 BMF, p < 0.005. When examined by revised IPSS (R-IPSS), severe BMF only impacted OS among the lower risk group. The median OS in patients with very low/low R-IPSS risk was 47mo in patients with severe BMF compared to 77 for those with grade 0-2 BMF, p = 0.015. In multivariable analysis, adjusting for age and R-IPSS, severe BMF was independently associated with inferior OS (HR 1.7, P 0.01). The rate of AML transformation was 28% in both the severe and grade 0-2 BMF groups, p = 0.98. Eighty patients with severe BMF were treated with hypomethylating agents (HMA). The overall response, by IWG 2006 criteria, of HI or better was 30% among patients with severe BMF compared to 32% of patients with grade 0-2 BMF, p 0.4. Among patients with severe BMF treated with lenalidomide (n=30), 25% of patients had HI response compared to 16% in patients with grade 0-2 BMF, p 0.9. The median OS for the 100 patients with severe BMF who did not undergo allogenic SCT was 23mo compared to 30mo for the 19 patients with severe BMF who did undergo allogenic SCT, p 0.29 Among somatic gene mutations, SF3B1 mutation was observed in 14% of grade 0-2 and 0% of grade 3 fibrosis. However, SRSF2 was present in 35.7% of patients with grade 3 fibrosis and only 9.7% of patients with grade 0-2 BMF, p .009. There was no statistically significant difference in the rate of occurrence of TP53 and RUNX1 mutations between the grade 0-2 BMF and the grade 3 BMF groups. In addition, there was no significant difference in the rate of occurrence of JAK2 mutation across the two groups. (table-2) Conclusions In our MDS cohort, only the presence of severe BMF (grade 3) was associated with worse outcome with reduced overall survival namely among patients with very low/low R-IPSS disease, whereas BMF grade did not impact response to HMA or lenalidomide treatment. SRSF2 gene mutation occurred with greater frequency among patients with severe fibrosis. Table 1 Baseline characteristics Table 1. Baseline characteristics Table 2 Acquired Somatic Mutations Table 2. Acquired Somatic Mutations Disclosures Sweet: Incyte Corporation: Research Funding; Ariad: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Pfizer: Speakers Bureau; Karyopharm: Honoraria, Research Funding. Bennett:Celgne: Membership on an entity's Board of Directors or advisory committees. Komrokji:Incyte: Consultancy; Novartis: Consultancy, Speakers Bureau; Boehringer-Ingelheim: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding.

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A Novel CSF3R Mutation Uncovers the Importance of Membrane-Proximal N-Glycosylation for Receptor Regulation

Blood ◽

10.1182/blood.v128.22.3141.3141 ◽

2016 ◽

Vol 128 (22) ◽

pp. 3141-3141

Author(s):

Seamus B Hughes ◽

David Spiciarich ◽

Richard D. Press ◽

Sarah L Thompson ◽

Jerald P. Radich ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Research Funding ◽

Consensus Sequence ◽

Myeloproliferative Neoplasm ◽

Receptor Activation ◽

Advisory Committees ◽

Chronic Neutrophilic Leukemia ◽

Cell Counts

Abstract Mutations in CSF3R (aka GCSFR) occur in the majority of patients with Chronic Neutrophilic Leukemia (CNL) and also are rarely found in adult and pediatric Acute Myeloid Leukemia. The most common CSF3R mutation in CNL is T618I (aka T595I), a point mutation in the membrane-proximal extracellular domain that causes ligand independence. Mutations that lead to a premature stop in the cytoplasmic domain are also found in CNL and result in increased expression of CSF3R on the cell surface. Understanding the biology of other novel mutations in CSF3R may lead to insight into both receptor biology and oncogenesis. The CSF3R N610H mutation was identified in a patient with a myeloproliferative neoplasm, which was most consistent with a JAK2, CALR, MPL mutation negative primary myelofibrosis. This patient had a history of mild leukocytosis for several years with most recent white blood cell counts between 13.3 and 15.3 x 103/uL. A bone marrow biopsy revealed 90% cellularity with mildly increased reticulin fibrosis, increased myeloid to erythroid ratio, no overt dysplasia, and less than 5% blasts. The cells were karotypically normal with a micro deletion of the 3' end of PDGFRB (5q) identified by FISH at 59%. The patient has had minimal symptoms with no anemia or thrombocytopenia and is currently being monitored but not receiving any intervention. The patient's bone marrow was next-generation sequenced using a 42-gene myeloid malignancy targeted mutation hotspot panel which revealed a mutation at N610H in CSF3R at a 50% mutant allele frequency. Given its proximity to the most common CSF3R mutation found in Chronic Neutrophilic Leukemia (T618I, aka T595I), we were interested in understanding whether the N610H mutation might contribute to disease biology. N610 (also known as N586 in the traditional numbering system that does not include the signal peptide) is part of an N-X-T motif, which is a consensus sequence for N-linked glycosylation. Haniu et al (Biochemistry 1996) demonstrated that N610 is one of 8 sites that are N-glycosylated on CSF3R. We confirm by mass spectrometry (MS) based analysis that N610 is occupied with a bisecting complex N-glycan (in vitro). We further found that the N610H mutation and a more conservative N610Q substitution are highly activating in CSF3R, leading to cytokine-independent growth in the murine Ba/F3 cell line. Furthermore, like the T618I mutation, these mutations render the receptor ligand-independent. N610H and N610Q lead to a robust increase in downstream signaling through the JAK/STAT pathway as demonstrated by an increase in the levels of phospho-STAT3. The loss of N-glycosylation in the membrane-proximal region of CSF3R may therefore increase ligand-independent receptor activation and promote oncogenesis. This study highlights the insight that rare human mutations can provide into the relationship between receptor structure and function. Disclosures Radich: Ariad: Consultancy; Novartis: Consultancy, Research Funding; Gilliad: Consultancy; Incyte: Consultancy. Bertozzi:GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Catalent Biologics: Membership on an entity's Board of Directors or advisory committees; Verily: Membership on an entity's Board of Directors or advisory committees; Enable Bioscience: Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Oh:CTI: Research Funding; Janssen: Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Transcriptional Landscape of the Microenvironment in Bone Marrow Fibrosis at Single Cell Level

Blood ◽

10.1182/blood-2019-126897 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1675-1675

Author(s):

Nils B. Leimkühler ◽

Ronghui Li ◽

Helene Gleitz ◽

Inge Snoeren ◽

Stijn Fuchs ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Research Funding ◽

Cell Level ◽

Bone Marrow Fibrosis ◽

Advisory Committees ◽

Molecular Alterations ◽

Ecm Proteins ◽

Travel Grant ◽

Marrow Fibrosis

Although the molecular alterations in hematopoietic cells which drive the development of myeloproliferative neoplasms (MPN) have been largely defined, reactive cellular alterations in the non-hematopoietic compartment remain rather obscure and have not been studied at single cell level. We therefore profiled enriched non-hematopoietic bone marrow cells by scRNAseq in bone marrow (BM) fibrosis compared to healthy marrow. BM fibrosis was induced by transplantation of hematopoietic stem and progenitor cells (HSPCs) with overexpression of Thrombopoietin (ThPO) into lethally irradiated mice. As ThPO-overexpression robustly leads to reticulin fibrosis in all mice (100%), we were able to study 1) pre-fibrosis (5 weeks after transplantation; reticulin fibrosis grade 0) and 2) manifest bone marrow fibrosis (10 weeks after transplantation, reticulin grade 2-3). The analysis revealed a total of 8 distinct clusters: 1-4) subpopulations of mesenchymal stromal cells (MSC-1: adipogenic, MSC-2: osteogenic, MSC-3: transition, MSC-4: interferonhigh), 5) osteoblastic lineage cells (OLCs), 6) arterial endothelial cells (ECs) and 7-8) Schwann cell precursors (SCP-1: non-myelinating SCPs; SCP-2: myelinating SCPs). Exposure to ThPO overexpressing HSPCs resulted in an overrepresentation of adipogenic MSCs at the expense of all other MSC subclusters. Differential gene expression analysis revealed a functional reprogramming of the "adipogenic" expanding MSCs with down-regulation of hematopoiesis-support and induction of a secretory phenotype including upregulation of various extracellular matrix (ECM) proteins driving fibrosis. Interestingly, only two MSC subclusters gained significant ECM expression indicating myofibroblast differentiation. Expansion of OLCs in BM fibrosis suggested a differentiation of the underrepresented MSC subpopulations into osteolineage cells which was confirmed by pseudotime analysis. Myelinating SCPs, highly expressing interleukin-33 (IL-33), showed the largest expansion in fibrosis. IL-33 is described to play a significant role in solid organ fibrosis by having both pro- and anti-fibrotic effects. Nerve injury triggers the expansion of myelinating and non-myelinating Schwann cells to promote repair, suggesting that mSCPs increase as compensatory and regenerative mechanism for the previously described MPN-induced sympathetic neuropathy. Dissection of cellular and molecular alterations in pre-fibrosis and manifest fibrosis demonstrated that only one MSC subpopulation was already significantly expanded in the pre-fibrotic phase, but only showed minor transcriptional changes. The upregulation of ECM proteins, osteogenesis as well as proinflammatory genes were hallmark features of manifest fibrosis. Interestingly, the overrepresentation of IL-33 expressing mSCPs was more pronounced in the pre-fibrotic phase, indicating that the expansion is a regenerative phenomenon failing in the stages of manifest fibrosis. Our findings were validated in the clinically relevant JAK2(V617F)-induced model of myelofibrosis. In conclusion, we here identified two distinct MSC subsets that are pro-fibrotic and contribute to osteosclerosis in PMF. The functional reprogramming of these MSCs in the bone marrow niche was accompanied by expansion of mSCPs with regenerative capacities, most likely caused by neural damage and Schwann cell death triggered by mutant HSCs. Disclosures Crysandt: Amgem: Other: travel grant; Pfizer: Other: travel grant; Gilead: Other: travel grant; Incyte: Membership on an entity's Board of Directors or advisory committees; celgene: Other: travel grant. Koschmieder: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; 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; Novartis: 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; Shire: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Ariad: 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; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; CTI: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis Foundation: Research Funding.

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Thrombopoietic Agents in the Treatment of Childhood Immune Thrombocytopenia (ITP): Clinical Treatment At 2 Centers

Blood ◽

10.1182/blood.v118.21.2230.2230 ◽

2011 ◽

Vol 118 (21) ◽

pp. 2230-2230

Author(s):

Kavitha Ramaswamy ◽

Loan Hsieh ◽

Hatice Melda Ürekli ◽

Diane J. Nugent ◽

James B Bussel

Keyword(s):

Bone Marrow ◽

Platelet Count ◽

Board Of Directors ◽

Research Funding ◽

Rescue Therapy ◽

Bone Marrow Fibrosis ◽

Advisory Committees ◽

Equity Ownership ◽

The Mean ◽

Marrow Fibrosis

Abstract Abstract 2230 Introduction: Thrombopoietic agents (TPO-A) are widely used in adults for difficult ITP. However only 1 study has been published describing the use of a TPO mimetic (Nplate) in 22 children with ITP. This study is a post hoc analysis of 32 children (<21yr) who received clinical treatment (off study) with either Nplate or Promacta. Methods: All children described are from 2 centers:,Weill Cornell in New York (n=22, 9 on Nplate, 13 on Promacta) and Childrens Hospital Orange County (10, all on Nplate). All patients in this abstract were treated off study although some had previously participated in the AMGEN195 (Pediatric) followed by AMGEN 213 (long term maintenance) studies. Responses (taken from the published study) were defined as platelet count (plt ct) > 50k on 2 consecutive weeks, plt increase ≥ 20k on 2 consecutive weeks, and the percent of weeks at ≤ 50k independent of rescue therapy. Rescue therapy e.g. IVIG, steroids, plt transfusion, resulted in counts being considered “non-responder” for 2 full weeks after initiation of treatment. Bone marrows were evaluated for reticulin fibrosis (RF) using consensus grades 0–3. Several patients had more than one marrow during treatment; in these cases, the most recent on-therapy marrow was used. Results: The median age of patients on Nplate was 10 years of age (2–19) while for those on Promacta it was 16 years (5–19). Of the 32 patients treated with TPO-A, 24 responded with a plt ct ≥ 50k twice; 19/32 received Nplate and 15/19 responded; 13/32 received Promacta and 9/13 responded. Plt increases ≥ 20k were seen in 23 of 32 patients. The number of patients whose platelet count was ≥ 50k for at least 50 percent of visits was 20/32. The mean number of previous treatments for responders to Nplate was 3.2 while for Nplate non-responders it was 2.25. For Promacta, the mean for responders was 2.9 treatments and for non-responders 3 treatments. Younger patients did not seem to respond as well to treatment with either TPO-A (see table). Nplate patients received treatment for a mean of 19.2 weeks; for patients treated with Promacta it was 13.7 weeks. Baseline bone marrows were available in 17 patients of whom 6 had grade 1 reticulin fibrosis (RF). There were 10 children with marrows performed after the start of TPO-A: 2 with RF score=0, 7 with score=1+, and 1 with score=2+ Adverse events (AEs) other than bone marrow fibrosis and bleeding (lack of efficacy) were all 1–2+ and not related to TPO-A. In particular, no thrombosis or development of malignancy was seen. In conclusion, TPO-A were an effective treatment of chronic ITP in the 32 consecutive children retrospectively analyzed here from 2 centers. Younger children in this study seemed not to respond as well as older children, in contrast to small numbers of young children in published data who responded very well. No major changes were seen in the bone marrows but a formal baseline and on therapy study in children is needed to assess this issue. AEs were infrequent and tolerable. Additional studies with both Nplate and Promacta, either planned or in progress, are needed to clarify the response rates, AEs eg bone marrow fibrosis, and effects in subgroups of children. Disclosures: Bussel: Portola: Consultancy; Eisai: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; GlaxoSmithKline: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Amgen: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Cangene: Research Funding; Genzyme: Research Funding; Immunomedics: Research Funding; Ligand: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Shionogi: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Sysmex: Research Funding.

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Bone Marrow Fibrosis In Immune Thrombocytopenia (ITP) Patients Treated With Thrombopoietin Receptor Agonists (TRA) – a Single Center Long-Term Follow-Up

Blood ◽

10.1182/blood.v122.21.3527.3527 ◽

2013 ◽

Vol 122 (21) ◽

pp. 3527-3527

Author(s):

Waleed Ghanima ◽

Julia Turbiner Geyer ◽

Christina Soo Lee ◽

Attilio Orazi ◽

Leonardo Boiocchi ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Research Funding ◽

Single Center ◽

Duration Of Treatment ◽

Bone Marrow Fibrosis ◽

Advisory Committees ◽

Equity Ownership ◽

Marrow Fibrosis

Abstract Introduction TRAs increase platelet counts by stimulating the TPO-receptor. A known effect of TRA treatment is increased bone marrow fibrosis (MF). This study explored extent of MF, its clinical relevance, and incidence of phenotypic or karyotypic abnormalities in TRA-treated ITP patients. Methods This single-center study was carried out at the Platelet Disorders Center of Weill Cornell Medical College (WCMC), NY, USA. Eligibility criteria were: diagnosis of ITP; treatment with a TRA (romiplostim, eltrombopag, AKR 501 (Eisai) or Shionogi agent), ≥ 1 bone marrow biopsy (BMB) performed during TRA treatment. BMBs were performed every 1–2 years as standard f/u procedure for our ITP patients on TRA. MF grade was assessed from MF-0 to MF-3 according to the European Consensus Grading System in 141 BMBs acquired prior to (n=15), during (n=117) and after (n=9) TRA-treatment from 66 patients. Fifty disease-free staging BMBs served as controls. BMBs were separately reviewed by 3 pathologists to assess the grade of MF and then reviewed concurrently as needed to reach consensus. The study was approved by the IRB of WCMC; informed written consent was obtained from patients. Results Median (Q1-Q3) age at the time of 1st BMB was 38 years (18-63); 34 males 32 females. 32 patients had > 2 on-treatment BMBs. The distribution of MF-grades is shown in the figure. The proportion of MF-0 decreased from 67% in pretreatment biopsies (BM0) to 21% in the first set of BMBs (BM1); in the 15 patients with pre- and on-treatment BMBs there was a significantly higher number of MF-0 in BM0 as compared to BM1 (10/15 vs. 3/15;p=0.016) suggesting that TRAs induce fibrosis in treated patients. In patients with multiple on-treatment BMBs (n=32), first on-treatment BMB was graded as MF-1 in 24. In the last set of biopsies (BM-Last) 8 had progressed to MF-2/3, 12 remained MF-1, and 4 became MF-0 illustrating the unpredictability of the future course of MF from the first on-treatment marrow. Nonetheless, a higher number of MF-2/3 BMB was found in BM-Last as compared to BM1 [10 (31%) vs. 3 (9%) of 32; p=0.039]. In 5 patients with MF-2/3 BMB, TRA were discontinued: on f/u 2 had less fibrosis, 1 remained the same, and 2 are awaiting f/u BMB. BMB was graded MF-0 in 54% and MF-1 in 46% of control BMB; no difference was found in the proportion of MF-0/1 and 2/3 in BM0 compared to controls, but increased MF-2/3 was seen in BM-last compared to controls (p<0.001). At BM-last in patients dichotomized by MF-0/1 vs. MF-2/3, differences in hemoglobin levels (13.6 vs. 12.4 g/dl, respectively), absolute neutrophil counts (4.8 vs. 7 x109/L), platelet counts (92 vs. 123 x109/L), and LDH levels (212 vs. 219 U/L) were not significantly different. Of the following 6 clinical factors: age, duration of disease, duration of treatment, splenectomy status, type and dose of agent; only age was significantly higher in patients with MF-2/3 as opposed to MF0/1 at time of BM-last [57 vs. 38 years; p=0.01]. There was a tendency toward longer duration of treatment in patients with MF-2/3 as compared to MF-0/1 (3.6 y vs. 2.7y; p=0.16). Flow cytometric immunophenotyping of BMB in 89 examinations did not reveal emergence of clonal abnormalities. Cytogenetic analysis in 72 BMBs did not show any clonal karyotypic abnormalities. Conclusions This large single center experience indicates that TRAs induce some degree of MF as supported by: 1) decreasing fraction of MF-0 after initiation of TRA, 2) decreasing fraction of MF-0/1 (normal grades of MF) in subsequent on-treatment BMBs, 3) increasing fraction of MF-2/3 (pathological grades) in patients with multiple on-treatment BMBs. Only older age was associated with higher grades of fibrosis. However, MF remained stable in most patients within the range found in normal individuals. Higher grades of MF (MF-2/3) observed in some patients were not clinically significant based on peripheral blood counts. Overall, since a number of patients developed MF-2 and even MF-3, this suggests a risk of progressive fibrosis in approximately 20% of patients. No neoplastic immunophenotypic or karyotypic abnormalities emerged during treatment with TRAs. Annual or bi-annual follow-up with BMB should be carefully considered in TRA-treated patients. Discontinuation of TRA should be encouraged in those who develop/progress to MF-3 and possibly even MF-2 to avoid potential further progression of MF Disclosures: Bussel: Amgen: Equity Ownership, Membership on an entity’s Board of Directors or advisory committees, Research Funding; GlaxoSmithKline: Equity Ownership, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Cangene: Research Funding; Genzyme: Research Funding; IgG of America: Research Funding; Immunomedics: Research Funding; Ligand: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Eisai: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Shionogi: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Sysmex: Research Funding; Symphogen: Membership on an entity’s Board of Directors or advisory committees.

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Dynamic Stromal Changes in Myelofibrosis Patients Pre/Post JAK Inhibition Is Revealed in Clinically Archived Bone Marrow Biopsies By Smooth Muscle Actin (SMA)-CD34 Dual Immunohistochemistry

Blood ◽

10.1182/blood-2021-151458 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 3286-3286

Author(s):

Katelyn Wang ◽

Iran Rashedi ◽

James T. England ◽

Rashmi S. Goswami ◽

Larissa Liontos ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Research Funding ◽

Smooth Muscle Actin ◽

Muscle Actin ◽

Analysis Pipeline ◽

Bone Marrow Fibrosis ◽

Advisory Committees ◽

Bone Marrow Biopsies ◽

Marrow Fibrosis

Abstract The natural history of BCR-ABL1 negative myeloproliferative neoplasms (MPNs) is progression towards an overt myelofibrotic (MF) phase with variable risk to develop secondary acute myeloid leukemia. Current treatments include Janus kinase inhibitors (JAKi) which can temporarily alleviate MF-related symptoms but are non-curative and most patients eventually progress to a more advanced stage. Given the negative prognostic impact of bone marrow fibrosis in MPNs and generally poor outcome post JAKi failure, it would be important to identify in situ biomarkers that address the initiation, perpetuation and early reversal of the fibrotic reaction. The current clinical standard for bone marrow fibrosis assessment involves reticulin/trichrome stains that detect relatively static extracellular matrix products rather than the fibrosis driving cells directly. To address this, we have developed a smooth muscle actin stromal-vascular (SMA-CD34) dual immunohistochemical (IHC) technique amenable to morphologic scoring and complemented with a CellProfiler image analysis pipeline. SMA was prioritized over other validated stromal IHC markers given work by others in experimental models demonstrating SMA+ myofibroblasts to be the differentiated output of critical fibrosis inducing Gli1+ 'driver' mesenchymal stem/progenitor cells in MPN. Herein, we demonstrate the feasibility of our translational approach using a clinically annotated cohort of MF patients from the Princess Margaret Cancer Centre MPN Registry. After selecting for high quality (>1.0 cm) paired pre and post JAKi biopsies amenable to image and transcriptome-based analysis, the pilot cohort was comprised of 13 cases with 38% high-risk, 54% intermediate-2 and 8% intermediate-1 risk by DIPSS. Driver mutations were JAK2 V617F (77%), CALR (15%) and other (8%). JAKi therapies included ruxolitinib (31%) + pelabresib (23%), momelotinib (15%), itacitinib (15%) and pacritinib (8%). The SMA-CD34 stromal assessment at baseline revealed distinct interstitial myofibroblast patterns and vascular perturbations not captured by conventional clinical hematopathology assessment (e.g. SMA+ dilated sinusoids). A SMA-CD34 scoring system was developed using a 4-point scale representing normal (0 pts), increased vascularity (1 pt), focal interstitial SMA (2 pts), multifocal interstitial SMA (3 pts) and diffuse SMA (4 pts). Scoring was then performed by blinded hematopathologists. A trend towards JAK2 mutated MF cases demonstrating higher SMA grade at baseline was noted. Interestingly, variable trajectories in SMA scores emerged following treatment with JAKi. Specifically, SMA signals had increased in 15%, decreased in 46% and were stable in 38% post-JAKi when using a morphologic SMA grading scheme. When compared to reticulin fibrosis, the severity of SMA signals had diverged in 1/3 of the cases (e.g. SMA grade decreased, reticulin grade stable). To further complement the SMA-CD34 morphologic grading, a CellProfiler image analysis pipeline was developed yielding a non-vessel associated normalized SMA area metric as a supervised correlate of the clinical SMA scoring system (R 2 = 0.68). Additional supervised and unsupervised bioinformatic approaches for clustering of relevant SMA-CD34 features including an algorithm that informs SMA spatial patterns with respect to niche elements such as arterioles (CD34+SMA+), sinusoids (CD34+) and adipocytes is in development. Lastly, Nanostring Fibrosis V2 panel was employed on a subset that met RNA concentration and quality metrics. Exploratory interpretation showed significant differentially expressed genes in pre vs. post JAKi specimens related to lipid metabolism such as ADIPOR1, SCD, ELOVL6 as well as the chemokine CXCL16. This may suggest a link between fatty acid metabolism and inflammatory differentiation along the SMA-vascular axis in the bone marrow modulated by JAKi treatment. SMA-CD34 IHC stratifies MF bone marrow biopsies differentially from standard WHO reticulin/trichome grading providing a practical formalin-fixed paraffin embedded (FFPE) tissue-based biomarker for assessing fibrosis related bone marrow niche elements from archived clinical samples. While our pilot numbers precluded statistical evaluation by JAKi-type, clinical response and NGS mutational profile at this time, further studies are underway to validate the SMA-CD34 signature on a larger MF cohort. Figure 1 Figure 1. Disclosures Gupta: Sierra Oncology: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS-Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy; Incyte: Honoraria, Research Funding; Constellation Pharma: Consultancy, Honoraria; Pfizer: Consultancy.

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Updated Results of Phase 2 Study of Ruxolitinib in Combination with 5-Azacitidine in Patients with Myelofibrosis

Blood ◽

10.1182/blood-2018-99-120251 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 352-352 ◽

Cited By ~ 2

Author(s):

Lucia Masarova ◽

Srdan Verstovsek ◽

Jorge E. Cortes ◽

Naveen Pemmaraju ◽

Prithviraj Bose ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Median Time ◽

Research Funding ◽

Phase 2 ◽

Bone Marrow Fibrosis ◽

Advisory Committees ◽

Phase 2 Study ◽

Grade 3

Abstract Background: JAK1/2 inhibitor ruxolitinib (RUX) abrogates symptoms and organomegaly in patients with myelofibrosis (MF). Combination with azacitidine (AZA) may further improve its efficacy. Methods: We initiated a single institutional, single arm, prospective, phase 2 study of RUX AZA combination in adult patients with MF and < 20% blasts. Previous therapy with RUX or AZA was not allowed. RUX 5 - 20 mg orally twice daily was given continuously since cycle 1. AZA 25 - 75 mg/m2 on days 1 - 5 of each 28-day cycle was added starting cycle 4. Responses were assessed per International Working Group for Myelofibrosis Research and Treatment 2013 criteria (IWG-MRT). Enrollment cut-off for this analysis was December 31st, 2017 to allow > 6 months of follow-up for all enrolled patients. We plan to present updated results with additional 5 months of enrollment at the meeting. Results: Fifty two pts were enrolled on study between 03/2013-12/2017, and were evaluable for responses. Forty seven pts (84%) were treated with both agents (RUX and AZA), with a median of 25 cycles (range, 1-55). Median age was 66 years (range, 48-87). Thirty four pts (65%) had int-2/high DIPSS score, 40 pts (77%) had spleen ≥5 cm. Thirty pts (58%) were JAK2V617F positive. Among 36 pts tested for non-driver mutations (28-gene panel); 7 pts had ASXL1, 6 had TET2, 3 had IDH1/2 and 2 had EZH2 and TP53. After a median follow-up of 22+ months (range, 1-59+); 21 pts (40%) are on therapy with a median overall follow-up of 30+ months. The most common reasons for therapy discontinuation were elective stem cell transplantation (n=12), and uncontrolled disease (n=8), including progression to acute leukemia (n=4). Four pts (8%) primarily discontinued therapy due to drug related toxicity (cytopenias). Three treatment unrelated deaths occurred on study; one each due to sepsis, meningitis and metastatic melanoma. Thirty eight pts (73%) had objective response on a study (Table). Median time to response was 1.8 months (range, 0.7-19). Seven responses (21% of responders) occurred after the addition of AZA with a median time to response of 2 months. These responses included spleen and symptom clinical improvements in 26% and 16% of pts, respectively. In total, 26 (65%), and 23 (58%) pts had palpable spleen reduction by > 50% at any time on study, and at week 24, respectively. JAK2V617F allele reduction was noted in 13 (81%) of 16 evaluable pts. Thirty one pts (60%) had available bone marrow for sequential evaluation. Nineteen pts (61%) had a documented improvement in bone marrow fibrosis, collagen or osteosclerosis, with a median time to first response of 12 months (range, 6-18). The most common grade ≥3 non-hematologic toxicity on a study was infection (34%), constipation (21%), and nausea (14%). New onset of grade ≥3 anemia, thrombocytopenia and neutropenia occurred in 33%, 30% and 16% of pts, respectively. Conclusion: Concomitant RUX with AZA was feasible with overall IWG-MRT response rate of 73%, including >50% spleen reduction in 65% of pts. Moreover, 61% of pts achieved improvement in bone marrow fibrosis, collagen or osteosclerosis. ClinicalTrials.gov Identifier: NCT01787487. Table. Disclosures Verstovsek: Celgene: Membership on an entity's Board of Directors or advisory committees; Incyte: Consultancy; Italfarmaco: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Cortes:novartis: Research Funding. Pemmaraju:novartis: Research Funding; daiichi sankyo: Research Funding; Affymetrix: Research Funding; plexxikon: Research Funding; samus: Research Funding; celgene: Consultancy, Honoraria; abbvie: Research Funding; cellectis: Research Funding; stemline: Consultancy, Honoraria, Research Funding; SagerStrong Foundation: Research Funding. Bose:Blueprint Medicines Corporation: Research Funding; Incyte Corporation: Honoraria, Research Funding; Constellation Pharmaceuticals: Research Funding; Astellas Pharmaceuticals: Research Funding; Pfizer, Inc.: Research Funding; CTI BioPharma: Research Funding; Celgene Corporation: Honoraria, Research Funding. Daver:Pfizer: Consultancy; Novartis: Research Funding; ImmunoGen: Consultancy; Alexion: Consultancy; Incyte: Consultancy; Karyopharm: Research Funding; Sunesis: Research Funding; Otsuka: Consultancy; Novartis: Consultancy; Karyopharm: Consultancy; Sunesis: Consultancy; Daiichi-Sankyo: Research Funding; ARIAD: Research Funding; Incyte: Research Funding; Kiromic: Research Funding; Pfizer: Research Funding; BMS: Research Funding.

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A Phase 2 Study of Cpi-0610, a Bromodomain and Extraterminal (BET) Inhibitor, in Patients with Myelofibrosis (MF)

Blood ◽

10.1182/blood-2018-99-119157 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 5481-5481 ◽

Cited By ~ 4

Author(s):

Marina Kremyanskaya ◽

Ronald Hoffman ◽

John Mascarenhas ◽

Srdan Verstovsek ◽

Jennifer Mertz ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Research Funding ◽

Inadequate Response ◽

Phase 2 ◽

Spleen Volume ◽

Bone Marrow Fibrosis ◽

Advisory Committees ◽

Phase 2 Study ◽

Marrow Fibrosis

Abstract MF is a myeloproliferative neoplasm characterized by abnormal megakaryocytes and elevated proinflammatory cytokines which results in bone marrow fibrosis, progressive hepatosplenomegaly due to extramedullary hematopoiesis, and debilitating constitutional symptoms. Current treatments, including ruxolitinib (the only approved drug for MF), provide symptomatic relief but have limited effects on the underlying disease. Effective therapies with potential MF disease course modification and second line therapies are urgently needed. CPI-0610 has been evaluated in 3 Phase 1 studies in > 140 patients with lymphoma, multiple myeloma and acute leukemias/myelodysplastic syndrome/MF. Although CPI-0610 was tested at doses as high as 400 mg PO QD, the maximum tolerated dose was 225 mg PO QD for 2 weeks on, 1 week off. Clear anti-tumor activity was observed in patients with lymphomas, particularly ABC-DLBCL (Blum et al. TAT conference 2018). Preclinical data on CPI-0610 demonstrated downregulation of pro-inflammatory cytokines through its effects on NF-κB pathway as well as inhibition of megakaryocyte differentiation. Both of these features are thought to be important in the pathogenesis of MF. In addition, a recent preclinical publication using a mouse model of MF, suggests that BET inhibition reduces inflammatory cytokine production, platelet counts, spleen volume and bone marrow fibrosis, the effects of which were further magnified when combined with ruxolitinib (Kleppe et al. 2018). Taken together, these data suggest that BET inhibitors such as CPI-0610, administered with and without ruxolitinib, have the potential to affect the underlying MF disease and supports further clinical evaluation of CPI-0610 in patients with MF. Therefore, we have embarked on a Phase 2 trial of CPI-0610 as monotherapy or in combination with ruxolitinib. This Phase 2 study aims to evaluate CPI-0610 as a monotherapy and in combination with ruxolitinib in patients with MF who are not eligible to receive a JAK inhibitor or have had an inadequate response to ruxolitinib. The primary objectives are to evaluate spleen volume response by imaging after 24 weeks of therapy and to evaluate the effect on transfusion independence rate. Other key secondary objectives are to evaluate the change in patient reported outcomes and the duration of splenic response. Exploratory objectives include characterizing the effects of treatment on the bone marrow and blood biomarkers. The Phase 2 study has a 2-stage design to enroll up to 35 patients in each arm (monotherapy and combination therapy) if ≥2 responses are observed during stage 1. The study is registered at ClinicalTrials.gov NCT02158858. Disclosures Kremyanskaya: Incyte: Research Funding. Hoffman:Formation Biologics: Research Funding; Summer Road: Research Funding; Incyte: Research Funding; Merus: Research Funding; Janssen: Research Funding. Mascarenhas:CTI Biopharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Promedior: Research Funding; Merck: Research Funding; Janssen: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees. Verstovsek:Italfarmaco: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Incyte: Consultancy; Celgene: Membership on an entity's Board of Directors or advisory committees. Mertz:Constellation Pharma: Employment. Garner:Constellation Pharma: Employment. Senderowicz:Constellation Pharma: Employment.

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