Genomic Characterization Provides Diagnostic Clarity in Cases with Overlapping Bone Marrow Fibrosis and Monocytosis

Abstract Introduction: Chronic myelomonocytic leukemia (CMML) and primary myelofibrosis (MF) are distinct myeloid malignancies with clinical and pathologic features that often overlap. The presence of significant bone marrow fibrosis with concomitant monocytosis can be diagnostically challenging. Distinguishing between these two clinical entities has important prognostic and therapeutic implications. In this study, we aimed to genomically characterize cases with overlapping features of both fibrosis and monocytosis and describe their clinical outcomes. Then, using well-established CMML and MF databases, we aimed to identify disease-specific genomic abnormalities to allow for improved diagnostic characterization. Methods: Including molecularly annotated patients (pts) from our CMML and MF databases, we created 3 cohorts. Cohort 1 was comprised of MF pts without significant monocytosis. Cohort 2 included CMML pts with absent/minimal bone marrow fibrosis. Cohort 3 included CMML pts with fibrosis and MF pts with monocytosis. Significant fibrosis defined as grade 2-3 by European consensus recommendations. Monocytosis defined as an absolute (>800/µL, the upper limit of normal in our laboratory) and relative (>10%) peripheral monocyte count. Cohorts 1 and 2 were compared to establish disease-specific somatic gene mutation patterns. Enriched variables were those that occurred significantly more often with p < 0.05. Specificity threshold of > 95% was used. Blinded pathological review of overlap bone marrow cases revealed concordance with original diagnosis in > 95% of cases. Results: Cohorts 1, 2 and 3 were comprised of 181, 168 and 61 pts, respectively. Among 61 pts in cohort 3, 26 had a prior CMML diagnosis and 35 had prior MF diagnosis. Median OS (mOS) in cohort 1 was 161 months (mo) compared to 35 mo in cohort 2 (p < 0.001) and 42 mo in cohort 3 (p < 0.001). mLFS for cohorts 1, 2, and 3 were not reached, 61 mo and 42 mo, respectively (p < 0.001). We compared molecular and cytogenetic abnormalities between cohort 1 and 2, assessing individual and commonly co-occurring abnormalities. Genomic abnormalities more common in CMML were mutations in TET2 (p < 0.001), RAS (p < 0.001), RUNX1 (p < 0.001), SRSF2 (p < 0.001), CBL (p = 0.05), ASXL1 (p = 0.04), TET2/SRSF2 (p < 0.001), TET2/ASXL1 (p < 0.001), TET2/RUNX1 (p = 0.03), SRSF2/ASXL1 (p = 0.004), and normal karyotype (p = 0.002). Genomic abnormalities more common in MF included driver mutations (i.e. JAK2, MPL, or CALR) (p < 0.001), del 20q (p = 0.03), del 13q (p < 0.001), and trisomy 9 (p = 0.004). Disease-specific abnormalities were those that were enriched in either CMML or MF with a specificity of >95%. CMML-specific abnormalities included RAS mutations and co-mutations in TET2/RUNX1, TET2/SRSF2, and SRSF2/ASXL1. MF-specific genomic abnormalities included del20q, del13q, and trisomy 9. We applied these disease-specific genomic abnormalities to cohort 3 to see if these findings could stratify pts toward a CMML-like genotype or MF-like genotype. Of 61 patients, 29 displayed only CMML-like genomic features (genomic CMML), 7 only MF-like features (genomic MF), 4 had both CMML and MF-specific features (genomic overlap) and 21 genomically undefined. Among those in cohort 3 with clinical MF diagnosis, 16 (46%) were reclassified as genomic CMML, 6 (17%) as genomic MF, 3 (9%) as genomic overlap, and 10 (31%) as genomically undefined. Among those with an original clinical diagnosis of CMML, 1 was redefined as genomic MF. OS for genomic CMML did not differ from genomic MF (p = 0.70). There was a trend for inferior LFS in genomic CMML compared to genomic MF (40 mo vs 59 mo, p = 0.19). Multivariate analysis identified the strongest prognostic features in cohort 3 as age > 70 (OR 9.4, p = 0.05), platelet count < 100,000/µL (OR 4.6, p = 0.02) and degree of bone marrow fibrosis (OR 5.1, p = 0.009). Conclusions: Specific genomic features distinguish CMML from MF. Application of these findings to pts with overlapping clinicopathologic features provides clarity in >50% of cases, primarily reclassifying patients as CMML. Clinically, outcomes in this overlap group with bone marrow fibrosis and monocytosis mirror those of CMML, regardless of genomic assignment; however, the presence of thrombocytopenia and magnitude of bone marrow fibrosis provide further prognostic discrimination. Future studies testing CMML-like therapeutic strategies should be considered in MF with monocytosis. Disclosures Kuykendall: Celgene: Honoraria; Janssen: Consultancy. Sweet:BMS: Honoraria; Celgene: Honoraria, Speakers Bureau; Jazz: Speakers Bureau; Astellas: Consultancy; Phizer: Consultancy; Novartis: Consultancy, Honoraria, Speakers Bureau; Agios: Consultancy; Jazz: Speakers Bureau; Agios: Consultancy; Phizer: Consultancy; Astellas: Consultancy; Novartis: Consultancy, Honoraria, Speakers Bureau; BMS: Honoraria; Celgene: Honoraria, Speakers Bureau. Sallman:Celgene: Research Funding, Speakers Bureau. List:Celgene: Research Funding. Komrokji:Novartis: Honoraria, Speakers Bureau; Celgene: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Novartis: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau.

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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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Efficacy and Safety of Eltrombopag for Treatment of Patients with Myelodysplastic Syndromes after Hypomethylating-Agent Failure: A Phase 2 Clinical Trial

Blood ◽

10.1182/blood.v126.23.1691.1691 ◽

2015 ◽

Vol 126 (23) ◽

pp. 1691-1691 ◽

Cited By ~ 2

Author(s):

Maliha Khan ◽

Bodden Kristy ◽

Tapan Kadia ◽

Alessandra Ferrajoli ◽

Yesid Alvarado ◽

...

Keyword(s):

Clinical Trial ◽

Bone Marrow ◽

Myelodysplastic Syndromes ◽

Research Funding ◽

Phase 2 ◽

Open Label ◽

Bone Marrow Fibrosis ◽

First Response ◽

Transfusion Requirements ◽

Marrow Fibrosis

Abstract Background: Myelodysplastic syndromes (MDS) are malignant clinical disorders characterized by ineffective hematopoiesis, bone marrow dysplasia, peripheral cytopenias and a property to transform into acute myeloid leukemia (AML). Standard of care for MDS includes the hypomethylating agents (HMAs) (i.e. azacitidine, decitabine) to improve quality of life, decrease transfusion requirements and improve clinical outcome. However not all patients (pts) respond to HMAs and even in responding pts, cytopenias may persist. HMA-failure MDS has extremely poor prognosis and currently there are no approved therapeutic options for such pts who are often of advanced age with frequent comorbidities. Objectives: The dual primary objectives of this study evaluate the safety and efficacy of the second-generation thrombopoietin-receptor agonist (TPO-RA) eltrombopag (EPAG) for the treatment of MDS pts at the time of HMA-failure. Secondary objectives include incidence of transformation to AML and evaluation of bone marrow fibrosis during therapy. Methods: Eligible pts for this 2-arm phase 2 open-label clinical trial included adults with MDS after completing >4 HMA cycles with failure to achieve at least a partial response, or the presence of ongoing cytopenias per IWG criteria. Arm A includes eltrombopag monotherapy and Arm B includes eltrombopag with continuation of the HMA at the previous dosing schedule. The starting eltrombopag dose is 200mg orally daily, which can be increased to 300mg in the absence of toxicity. First response is assessed after 2 cycles with each cycle lasting 28 days. The primary efficacy endpoint was overall response rate based on the IWG-2006 criteria. Results: To date, 23 pts with a median age of 72 years (range 42-84 years) have been enrolled. Prior to study entry, pts had received a median of 6 (range 4-25) HMA cycles. Cytogenetics were diploid in 12 (53%), intermediate in 7 (30%), and high risk in 4 (17%) pts by IPSS. Median bone marrow blasts at study start was 3% (range 0-15%). Arm A has enrolled 7 pts with a median age of 74 years; Arm B has enrolled 16 pts with median age of 69 years. In Arm B, ongoing HMA therapy includes azacitidine in 7 (44%) and decitabine in 9 (56%). Nine (39%) pts increased to 300mg EPAG after median of 8 weeks on study. Median total cycles received on study is 5 (1-17); median OS has not been reached. Overall, 16 pts are response-evaluable; 7 pts discontinued prior to the first response assessment at 2 months (4 due to AEs including myalgias/fatigue (n=2), hyperbilirubinemia (n=1), and pneumonia (n=1), 2 per pt request and 1 for pt inability to comply with protocol requirements). Of the 16 response-evaluable pts, 3 (19%) in Arm B demonstrated platelet improvement, including one pt necessitating EPAG dose-reduction to 100mg due to platelet count exceeding 450 x10⁹/L with concomitant ANC recovery at 200mg EPAG dose level. An additional 8 (35%) pts have remained on study for a median of 5 cycles (2-17) with stable disease. Two pts discontinued therapy due to disease progression, including 1 (4%) that progressed to AML. The most common non-hematologic AEs regardless of attribution included hyperbilirubinemia (n=14, 61%), fatigue (n=13, 56%) myalgias (n=11, 48%), fever (7, 30%), dyspnea (7, 30%), nausea (6, 26%) and transaminitis (4, 17%). No significant increase in bone marrow fibrosis has been observed. Conclusion: Eltrombopag orally daily appears to be a safe and beneficial supportive adjunct for pts with MDS while receiving HMA-therapy or after HMA-failure due to persistent cytopenias. Treatment on this study continues and larger prospective clinical trials are needed to confirm these preliminary findings. Disclosures Off Label Use: Eltrombopag for the treatment of MDS-related cytopenias". Pemmaraju:Stemline: Research Funding; Incyte: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding; LFB: Consultancy, Honoraria. Konopleva:Novartis: Research Funding; AbbVie: Research Funding; Stemline: Research Funding; Calithera: Research Funding; Threshold: Research Funding. DiNardo:Novartis: Research Funding.

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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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Genetic and Clinical Features of Chronic Myelmonocytic Leukemia with Fibrosis

Blood ◽

10.1182/blood-2019-128997 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 5442-5442

Author(s):

Mohammad O Hussaini ◽

Jinming Song ◽

Andrew T Kuykendall ◽

David A Sallman ◽

Eric Padron ◽

...

Keyword(s):

Bone Marrow ◽

Risk Stratification ◽

Gene Panel ◽

World Health ◽

Pathology Report ◽

Monocyte Count ◽

Bone Marrow Fibrosis ◽

Worse Prognosis ◽

Marrow Fibrosis ◽

Severe Fibrosis

Introduction Chronic myelomonocytic leukemia (CMML) is an overlap syndrome with both myeloproliferative and myelodysplastic features. Clinical outcomes can be variable and risk stratification models such as GFM and Molecular Mayo Model (MMM) are useful. These models integrate age, WBC, anemia, thrombocytopenia, mutation status, monocyte count, and blast/promonocyte count, to segregate patients1. The presence of fibrosis in MDS (MF 2-3) is often associated with high grade disease, poor cytogenetics, and worse prognosis 2. The role of moderate to severe fibrosis in CMML (CMML-F) is not well studied. We investigated mutational landscape of CMML-F and whether CMML-F is associated with more aggressive disease thus warranting incorporation into risk models. Methods Total Cancer Care (TCC) and PathNet databases at Moffitt Cancer Center were queried for patients diagnosed with CMML between 2014 and 2017 with available Next Generation Sequencing (NGS) profiling (Genoptix 5-gene panel, Genoptix 21-gene panel, FoundationOne, Custom TrueSeq Myeloid). The cases were individually reviewed by a board-certified hematopathologist to confirm the diagnosis. The degree of reticulin fibrosis was manually collated from the pathology report and graded according to the World Health Organization (WHO) grading of bone marrow fibrosis (grade 0-3). Grade 1-2 or 2-3 fibrosis in the report were designated 1.5 and 2.5, respectively. CMML-F was defined as grade 2.5 or higher or collagen fibrosis. t-test and two tailed Fisher exact tests were performed for statistical analysis. Results Of 108 CMML patients (median age of 69.7 years), bone marrow fibrosis data was available for 91 individuals. The degree of fibrosis was as follows: Grade 0= 33, Grade 1= 34, Grade 1.5= 2, Grade 2= 15, Grade 2.5= 2, Grade 3=5 (of which 2 had collagen fibrosis). The CMML patients without fibrosis (MF<2.5) showed a longer median overall survival when compared to CMML-F (24.79 months versus 20.43 months; p=0.67), but it was not statistically significant. One of the 8 CMML-F patients had AML transformation (12.5%), similar to the 9 out of 82 CMML patients without fibrosis (11%). One of 2 patients (50%) with collagen fibrosis showed leukemic transformation, higher than the transformation rate in non-collagen fibrosis patients (11%; p=0.21). The most common mutations in CMML-F were: ASXL1 (25%), SRSF2 (25%), JAK2 (16.7%), and TET2 (16.7%). The most common mutations in non-CMML-F were: TET2 (60%), ASXL1 (45%), SRSF2 (38%), and RUNX1 (19%). Of note, TET2 mutations was less likely to occur in CMML-F (p=0.008). The average marrow blast percentage in CMML-F was 4.2% while in non-CMML-f was 8.6% (p=0.25). Conclusions: In this study we demonstrate that CMML-F is less likely to harbor TET2 mutations than CMML without fibrosis. However, unlike MDS, the presence of moderate-to-severe fibrosis does not correlate with worse prognosis in CMML. Large cohorts warranted to identify novel prognostic markers that could be incorporated into risk stratification schemas. Disclosures Kuykendall: Incyte: Honoraria, Speakers Bureau; Janssen: Consultancy; Abbvie: Honoraria; Celgene: Honoraria. Sallman:Celyad: Membership on an entity's Board of Directors or advisory committees. Komrokji:JAZZ: Consultancy; Agios: Consultancy; Incyte: Consultancy; DSI: Consultancy; pfizer: Consultancy; celgene: Consultancy; Novartis: Speakers Bureau; JAZZ: Speakers Bureau.

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Trial in Progress: Phase Ib/II Study of Bcl-2/Bcl-Xl Inhibitor Pelcitoclax (APG-1252) in Patients with Myelofibrosis (MF) That Progressed after Initial Therapy

Blood ◽

10.1182/blood-2020-137260 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 15-16

Author(s):

Naveen Pemmaraju ◽

Boyd Mudenda ◽

Cunlin Wang ◽

Jiao JI ◽

Ming Lu ◽

...

Keyword(s):

Bone Marrow ◽

Clinical Benefit ◽

Research Funding ◽

Publicly Traded ◽

Bone Marrow Fibrosis ◽

Dual Inhibitor ◽

Jak2 Inhibitor ◽

Grant Support ◽

Marrow Fibrosis ◽

Jak2 Inhibitors

Background: Pelcitoclax (APG-1252), a novel dual inhibitor of Bcl-2/Bcl-xL, is active as monotherapy in patients with advanced solid tumors and well tolerated up to 240 mg twice weekly (NCT03387332). Preclinical data suggest that cells with Janus-associated kinase-2 (JAK2) mutations, including those associated with bone marrow fibrosis, are dependent on Bcl-2/Bcl-xL for survival and that addition of BH3 mimetics targeting Bcl-2/Bcl-xL induces apoptosis. Furthermore, in JAK2‒mutated cell models, apoptotic synergy is demonstrated when a JAK2 inhibitor and Bcl-2/Bcl-xL inhibitor are combined, as inhibition of Bcl-xL overcomes resistance to JAK2 inhibitors. Taken together, APG-1252 could overcome resistance to JAK2 inhibitors, and the combination could augment clinical benefit in patients with suboptimal responses to JAK2 inhibitor‒based therapy. Study Objectives: The primary objective of this open-label trial is to evaluate the safety and efficacy of APG-1252, as monotherapy and when combined with ruxolitinib, in adults with histologically or cytologically confirmed MF who require therapy and are ineligible for JAK2 inhibitors (and can receive single-agent APG-1252) or have had inadequate responses to ruxolitinib-based therapy (and can receive this treatment plus APG-1252). Secondary objectives include APG-1252 pharmacokinetics, time to response, and duration of response. Exploratory objectives include changes in cytogenetics and molecular mutations, bone marrow fibrosis, and cytokines on treatment. Study Design: The study is divided into Part 1 (APG-1252 monotherapy) and Part 2 (APG-1252 plus ruxolitinib). For Part 1, the key inclusion criterion is ineligibility for JAK2 inhibitors and for Part 2, inadequate responses to prior ruxolitinib-based therapy. A standard 3+3 dose-escalation design is being implemented to determine the maximum tolerated dose (MTD) of APG-1252 monotherapy in Part 1 and APG-1252 combined with ruxolitinib in Part 2. APG-1252 will initially be administered at 160 mg intravenously by 30-minute injection once weekly in a 28-day cycle. The dose can be escalated to a maximum of 240 mg or reduced to a minimum of 80 mg, depending on tolerability. Part 2 will begin once the MTD and recommended phase 2 dose (RP2D) of APG-1252 monotherapy have been determined. In Part 2, ruxolitinib will be administered orally twice daily per the package insert. After the MTD for APG-1252 monotherapy has been determined, no additional patients will be enrolled in Part 1; however, up to 15 to 30 additional patients can be enrolled in Part 2, to further evaluate the safety and anticancer activity of the combination at MTD or RP2D. Patients will continue treatment until disease progression or unacceptable toxicity. Clinical responses are being assessed every 12 weeks according to criteria from the International Working Group‒Myeloproliferative Neoplasms Research and Treatment and European LeukemiaNet panels, while optimal clinical benefit will be evaluated at 24 weeks. Enrollment will be from September 2020 and preliminary results estimated in October 2022. For further information, contact: [email protected]. Registration: ClinicalTrials.gov Identifier NCT04354727. Disclosures Pemmaraju: Pacylex Pharmaceuticals: Consultancy; Roche Diagnostics: Honoraria; LFB Biotechnologies: Honoraria; Stemline Therapeutics: Honoraria, Research Funding; Celgene: Honoraria; AbbVie: Honoraria, Research Funding; MustangBio: Honoraria; Affymetrix: Other: Grant Support, Research Funding; Cellectis: Research Funding; Daiichi Sankyo: Research Funding; Plexxikon: Research Funding; Samus Therapeutics: Research Funding; DAVA Oncology: Honoraria; Blueprint Medicines: Honoraria; Novartis: Honoraria, Research Funding; Incyte Corporation: Honoraria; SagerStrong Foundation: Other: Grant Support. Mudenda:Ascentage Pharma Group Inc.: Current Employment, Current equity holder in publicly-traded company. Wang:Ascentage Pharma Group Inc.: Current Employment, Current equity holder in publicly-traded company. JI:Ascentage Pharma (Suzhou) Co., Ltd.: Current Employment, Current equity holder in publicly-traded company. Lu:Ascentage Pharma Group: Current Employment, Current equity holder in publicly-traded company. Fu:Ascentage Pharma Group Inc.: Current Employment, Current equity holder in publicly-traded company. Liang:Ascentage Pharma Group Inc.: Current Employment, Current equity holder in publicly-traded company. McClain:Ascentage Pharma Group Inc.: Current Employment, Current equity holder in publicly-traded company. Sheladia:Ascentage Pharma Group Inc.: Current Employment, Current equity holder in publicly-traded company. Verstovsek:Novartis: Consultancy, Research Funding; Sierra Oncology: Consultancy, Research Funding; Blueprint Medicines Corp: Research Funding; PharmaEssentia: Research Funding; ItalPharma: Research Funding; AstraZeneca: Research Funding; Protagonist Therapeutics: Research Funding; Promedior: Research Funding; Celgene: Consultancy, Research Funding; NS Pharma: Research Funding; Genentech: Research Funding; CTI Biopharma Corp: Research Funding; Incyte Corporation: Consultancy, Research Funding; Roche: Research Funding; Gilead: Research Funding. Yang:Ascentage Pharma (SuZhou) Co., Ltd: Current Employment, Current equity holder in publicly-traded company, Other: Leadership and other ownership interests. Zhai:Ascentage Pharma (SuZhou) Co., Ltd: Current Employment, Current equity holder in publicly-traded company, Other: Leadership and other ownership interests.

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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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Eltrombopag for the Management of Thrombocytopenia Associated with Tyrosine Kinase Therapy in Patients with Chronic Myeloid Leukemia and Myelofibrosis

Blood ◽

10.1182/blood.v128.22.3062.3062 ◽

2016 ◽

Vol 128 (22) ◽

pp. 3062-3062

Author(s):

Abdallah Abou Zahr ◽

Jorge E. Cortes ◽

Srdan Verstovsek ◽

Jairo Matthews ◽

Nitin Jain ◽

...

Keyword(s):

Bone Marrow ◽

Platelet Count ◽

Myeloid Leukemia ◽

Research Funding ◽

Liver Enzymes ◽

Platelet Response ◽

Bone Marrow Fibrosis ◽

Grade 3 ◽

Dose Reductions ◽

Marrow Fibrosis

Abstract Background: Grade ≥ 3 thrombocytopenia occurs in 20-45% of patients with chronic myeloid leukemia (CML) treated with tyrosine kinase inhibitors (TKI). While most instances resolve with TKI transient interruptions and dose reductions, persistent or recurrent thrombocytopenia may adversely influence TKI efficacy. Similarly, patients with myelofibrosis (MF) treated with ruxolitinib may experience thromobocytopenia requiring dose adjustments and interruptions, also potentially affecting efficacy. Methods: We initiated a pilot study to assess the efficacy of eltrombopag for patients with CML or MF with persistent or recurrent thrombocytopenia after ≥3 months of therapy with an approved TKI or ruxolitinib, respectively. The primary objective is recovery of platelet count. Secondary objectives include safety, TKI/ruxolitinib dose intensity and response to therapy after start of therapy with eltrombopag. Patients with grade ≥ 3 thrombocytopenia (platelets <50 x 109/L) for patients with CML or platelets <100 x 109/L for patients with MF after at least 3 months of therapy with TKI or ruxolitinib, or those with prior grade 3 thrombocytopenia requiring TKI/ruxolitinib dose reductions or interruptions interfering with response, were enrolled. Starting dose for Eltrombopag is at 50 mg daily (25 mg for patients of East Asian ancestry) with dose escalation allowed every 2 weeks to a maximum of 300 mg daily according to platelet response. Safety monitoring includes liver enzymes and periodic evaluation of bone marrow fibrosis. Planned accrual is for 39 patients (29 patients with CML and 10 with MF). The target response is at least 30% of subjects to have a complete (platelet) response, which is defined as platelet count ≥50 x 109/L for CML, and ≥100 x 109/L for MF that is sustained for 3 months while continuing TKI therapy. This report is an interim analysis of futility and toxicity. Results: Nineteen patients have been enrolled (CML=14, MF=5). Median age is 58 years (range, 29-97 years); median duration of disease 2.1 years (range, 0.5-29 years) for patients with CML and 2 years (range, 0.3-3.6 years) for patients with MF. At the time of enrollment, patients with CML were treated with following TKIs: dasatinib (4), nilotinib (3), ponatinib (3), bosutinib (3), and imatinib (1). Median platelet count for patients with CML was 37 (range, 14-51), and 60 (range, 25 to 91) for those with MF. Cytogenetic response for patients with CML at baseline were: partial=3, minor=6, and none=5. After a median duration of treatment of 17 months (range, 3-48.4 months), 11 of 14 patients with CML achieved complete platelet response at eltrombopag doses of 50 - 300 mg per day. One additional patient with CML had a transient response. Median peak platelet count among responders was 224 (range, 123-424) x 109/L. In addition 7 patients with CML have had improvement in cytogenetic responses: 1 from none to complete, 3 from minor to partial, 1 minor to complete, 2 from partial to complete. None of the 5 patients with MF had a sustained increase in platelet count to ≥ 100 x 109/L. Two patients (1 each of CML and MF) had improvement in hemoglobin of over 2 gm/dL from baseline (from 8.2 g/dl to 10.6 g/dl, and from 9.4 g/dl to 11.4 g/dl, respectively), and 1 patient with CML had absolute neutrophil count recovery to >1x109/L (baseline neutrophils 0.71 x109/L). In 2 patients with CML, TKI dose could be increased and maintained while continuing eltrombopag. Grade3/4 toxicities irrespective of attribution include infection (n=5, 3 MF and 2 CML), elevated liver enzymes (n=5, all in CML), hyperglycemia (n=2), fatigue (n=2), chest pain (n=1), and myocardial infarction (n=1). One patient with MF showed increase in bone marrow fibrosis from grade 2 to grade 3. No progression of disease has been documented in any patient. One patient died on study from septic and hemorrhagic shock not related to study drug. Seven of the 19 patients enrolled are still on study. One patient discontinued therapy secondary to toxicity (persistent transaminitis with accompanying lack of response). Conclusion: Eltrombopag may alleviate thrombocytopenia in some patients with CML treated with TKI. This is frequently accompanied by a decrease in treatment interruptions, and improved response. No similar benefit has been observed in patients with MF treated with ruxolitinib. This study continues enrollment. Disclosures Cortes: ARIAD: Consultancy, Research Funding; Bristol-Myers Squib: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Teva: Research Funding. Jain:Servier: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Genentech: Research Funding; Celgene: Research Funding; BMS: Research Funding; Incyte: Research Funding; Infinity: Research Funding; Pharmacyclics: Consultancy, Honoraria, Research Funding; Novimmune: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria, Research Funding; ADC Therapeutics: Consultancy, Honoraria, Research Funding; Seattle Genetics: Research Funding; Abbvie: Research Funding. Jabbour:ARIAD: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Novartis: Research Funding; BMS: Consultancy. Kantarjian:Amgen: Research Funding; ARIAD: Research Funding; Bristol-Myers Squibb: Research Funding; Pfizer Inc: Research Funding; Delta-Fly Pharma: Research Funding; Novartis: Research Funding.

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