scholarly journals Inhibition of De Novo Pyrimidine Nucleotide Synthesis By the Novel DHODH Inhibitor PTC299 Induces Differentiation and/or Death of AML Cells

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 5152-5152
Author(s):  
Marla Weetall ◽  
Kensuke Kojima ◽  
Sujan Piya ◽  
Christopher Trotta ◽  
John Baird ◽  
...  
Keyword(s):  
Board Of Directors ◽  
Research Funding ◽  
De Novo ◽  
Salvage Pathway ◽  
De Novo Synthesis ◽  
Dna Breaks ◽  
Advisory Committees ◽  
Pyrimidine Nucleotides ◽  
Nucleotide Synthesis ◽  
Pyrimidine Nucleotide

Background: Pyrimidine nucleotides are generated either by de novo synthesis or the salvage pathway in which pyrimidine nucleotides are obtained from the diet. Resting cells typically acquire adequate pyrimidine nucleotides from the salvage pathway. Rapidly proliferating cells, however, are dependent on the de novo synthesis of pyrimidine nucleotides. PTC299 is an inhibitor of dihydroorotate dehydrogenase (DHODH), a rate limiting enzyme for de novo pyrimidine nucleotide synthesis that had previously been in clinical trials for treatment of solid tumors. Results: Using 15N-labelled glutamine, we show that PTC299 reduces de novo pyrimidine nucleotide synthesis in PTC299-sensitive AML cell lines resulting in a depletion of total pyrimidine nucleotides. In parallel to reduction in pyrimidine nucleotides, PTC 299 leads to accumulation of DHO, the substrate of DHODH and unexpectedly, an accumulation of N-carbamoyl aspartate the metabolite above DHO in the de novo pyrimidine nucleotide synthesis pathway. PTC299 was broadly active against leukemia and lymphoma lines, with 80% of the AML lines tested showing sensitivity. Treatment of AML cell lines with PTC299 induced differentiation as shown by increased CD14 and/or reduced proliferation. Using isogenic AML lines, we show that PTC299 reduces the proliferation of both p53 wildtype and p53 deficient leukemia calls with similar potency as measured by the concentration of PTC299 required to reduce cell number by 50% (CC50). In cells expressing wildtype p53, PTC299 increases p53 activation. However, p53- wildtype cells undergo increased apoptosis whereas p53-deficience cells undergo necrosis. PTC299 induced a G1/S cell cycle arrest, also independent of p53 status. PTC299 increased H2A.X (a marker of double stranded DNA breaks) in both p53 wildtype and p53 deficient cells. These data suggest that the depletion of nucleotides results in stalling at the replication fork, and subsequent DNA-breaks. Conclusion: De novo pyrimidine nucleotide synthesis is critical for AML survival and proliferation. Depletion of nucleotides results in reduced proliferation, triggering either differentiation and/or cell death. Disclosures Weetall: PTC Therapeutics: Employment. Trotta:PTC Therapeutics: Employment. Baird:PTC Therapeutics: Employment. O'Keefe:PTC Therapeutics: Employment. Furia:PTC Therapeutics: Employment. Borthakur:PTC Therapeutics: Consultancy; Janssen: Research Funding; AbbVie: Research Funding; Argenx: Membership on an entity's Board of Directors or advisory committees; NKarta: Consultancy; AstraZeneca: Research Funding; Xbiotech USA: Research Funding; Incyte: Research Funding; GSK: Research Funding; Oncoceutics, Inc.: Research Funding; Novartis: Research Funding; Agensys: Research Funding; BMS: Research Funding; Oncoceutics: Research Funding; Cantargia AB: Research Funding; Bayer Healthcare AG: Research Funding; Eisai: Research Funding; FTC Therapeutics: Membership on an entity's Board of Directors or advisory committees; BioTheryX: Membership on an entity's Board of Directors or advisory committees; Polaris: Research Funding; Merck: Research Funding; Cyclacel: Research Funding; Eli Lilly and Co.: Research Funding; BioLine Rx: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Arvinas: Research Funding; Tetralogic Pharmaceuticals: Research Funding; Strategia Therapeutics: Research Funding. Spiegel:PTC Therapeutics: Consultancy.

scholarly journals Inhibition of De Novo Pyrimidine Synthesis Depletes Acute Myleogenous Leukemia Stem Cells (LSCs) Burden and Triggers Apoptosis and Differentiation Associated with Oxidative Stress

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2249-2249
Author(s):  
Sujan Piya ◽  
Huaxian Ma ◽  
Priyanka Sharma ◽  
Kensuke Kojima ◽  
Vivian Ruvolo ◽  
...  
Keyword(s):  
Stem Cells ◽  
Acute Myeloid Leukemia ◽  
Board Of Directors ◽  
Myeloid Leukemia ◽  
Research Funding ◽  
De Novo ◽  
Leukemia Stem Cells ◽  
Advisory Committees ◽  
Nucleotide Synthesis ◽  
Acute Myeloid

Abstract Background: De novo nucleotide synthesis is necessary to meet the enormous demand for nucleotides, other macromolecules associated with acute myeloid leukemia (AML) progression 1, 2, 3 4. Hence, we hypothesized that targeting de novo nucleotide synthesis would lead to the depletion of the nucleotide pool, pyrimidine starvation and increase oxidative stress preferentially in leukemic cells compared to their non-malignant counterparts, impacting proliferative and differentiation pathways. Emvododstat (PTC299) is an inhibitor of dihydroorotate dehydrogenase (DHODH), a rate-limiting enzyme for de novo pyrimidine nucleotide synthesis that is currently in a clinical trial for the treatment of AML. Objectives: The goals of these studies were to understand the emvododstat-mediated effects on leukemia growth, differentiation and impact on Leukemia Stem Cells(LSCs). Comprehensive analyses of mitochondrial function, metabolic signaling in PI3K/AKT pathways, apoptotic signatures, and DNA damage responses were carried out. The rationale for clinical testing emvododstat was confirmed in an AML-PDX model. Results: Emvododstat treatment in cytarabine-resistant AML cells and primary AML blasts induced apoptosis, differentiation, and reduced proliferation, with corresponding decreased in cell number and increases in annexin V- and CD14-positive cells. Indeed, the inhibition of de novo nucleotide synthesis compromises the dynamic metabolic landscape and mitochondrial function, as indicated by alterations in the oxygen consumption rate (OCR) and mitochondrial ROS/membrane potential and corresponding differentiation, apoptosis, and/or inhibition of proliferation of LSCs. These effects can be reversed by the addition of exogenous uridine and orotate. Further immunoblotting and mass cytometry (CyTOF) analyses demonstrated changes in apoptotic and cell signaling proteins (cleaved PARP, cleaved caspase-3) and DNA damage responses (TP53, γH2AX) and PI3/AKT pathway downregulation in response to emvododstat. Importantly, emvododstat treatment reduced leukemic cell burden in a mouse model of AML PDX ( Complex karyotype ,mutation in ASXL1, IDH2, NRAS), decreased levels of leukemia stem cells frequency (1 in 522,460 Vs 1 in 3,623,599 in vehicle vs emvododstat treated mice), and improved survival. The median survival 40 days vs. 30 days, P=0.0002 in primary transplantation and 36 days vs 53.5 days, P=0.005 in secondary transpantation in a PDX mouse model of human AML. This corresponded with a reduction in the bone marrow burden of leukemia and increased expression of differentiation markers in mice treated with emvododstat (Fig. 1). These data demonstrate effect of emvododstat on mitochondrial functions . Conclusion: Inhibition of de novo pyrimidine synthesis triggers differentiation, apoptosis, and depletes LSCs in AML models. Emvododstat is a novel dihydroorotate dehydrogenase inhibitor being tested in a clinical trial for the treatment of myeloid malignancies and COVID-19. Keywords: AML, emvododstat, DHODH, apoptosis, differentiation References: 1 Thomas, D. & Majeti, R. Biology and relevance of human acute myeloid leukemia stem cells. Blood 129, 1577-1585, doi:10.1182/blood-2016-10-696054 (2017). 2 Quek, L. et al. Genetically distinct leukemic stem cells in human CD34- acute myeloid leukemia are arrested at a hemopoietic precursor-like stage. The Journal of experimental medicine 213, 1513-1535, doi:10.1084/jem.20151775 (2016). 3 Villa, E., Ali, E. S., Sahu, U. & Ben-Sahra, I. Cancer Cells Tune the Signaling Pathways to Empower de Novo Synthesis of Nucleotides. Cancers (Basel) 11, doi:10.3390/cancers11050688 (2019). 4 DeBerardinis, R. J. & Chandel, N. S. Fundamentals of cancer metabolism. Sci Adv 2, e1600200, doi:10.1126/sciadv.1600200 (2016). Figure 1 Figure 1. Disclosures Weetall: PTC therapeutics: Current Employment. Sheedy: PTC therapeutics: Current Employment. Ray: PTC therapeutics: Current Employment. Andreeff: Karyopharm: Research Funding; AstraZeneca: Research Funding; Oxford Biomedica UK: Research Funding; Aptose: Consultancy; Daiichi-Sankyo: Consultancy, Research Funding; Syndax: Consultancy; Breast Cancer Research Foundation: Research Funding; Reata, Aptose, Eutropics, SentiBio; Chimerix, Oncolyze: Current holder of individual stocks in a privately-held company; Novartis, Cancer UK; Leukemia & Lymphoma Society (LLS), German Research Council; NCI-RDCRN (Rare Disease Clin Network), CLL Foundation; Novartis: Membership on an entity's Board of Directors or advisory committees; Senti-Bio: Consultancy; Medicxi: Consultancy; ONO Pharmaceuticals: Research Funding; Amgen: Research Funding; Glycomimetics: Consultancy. Borthakur: ArgenX: Membership on an entity's Board of Directors or advisory committees; Protagonist: Consultancy; Astex: Research Funding; University of Texas MD Anderson Cancer Center: Current Employment; Ryvu: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy.

scholarly journals Long-Term Experience with Large Granular Lymphocytic Leukemia Evolving after Solid Organ and Hematopoietic Stem Cell Transplantation

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1226-1226
Author(s):  
Hassan Awada ◽  
Reda Z. Mahfouz ◽  
Jibran Durrani ◽  
Ashwin Kishtagari ◽  
Deepa Jagadeesh ◽  
...  
Keyword(s):  
Board Of Directors ◽  
Research Funding ◽  
Viral Infections ◽  
De Novo ◽  
Post Transplantation ◽  
Advisory Committees ◽  
Hematopoietic Stem ◽  
Post Transplant ◽  
Stat3 Mutations

T-cell large granular lymphocyte leukemia (T-LGLL) is a clonal proliferation of cytotoxic T lymphocytes (CTL). T-LGLL mainly manifest in elderly and is associated with autoimmune diseases including rheumatoid arthritis (RA), B cell dyscrasias, non-hematologic cancers and immunodeficiency (e.g., hypogammaglobulinemia). LGL manifestations often resemble reactive immune processes leading to the dilemmas that LGLs act like CTL expansion during viral infections (for example EBV associated infectious mononucleosis). While studying a cohort of 246 adult patients with T-LGLL seen at Cleveland Clinic over the past 10 years, we encountered 15 cases of overt T-LGLL following transplantation of solid organs (SOT; n=8) and hematopoietic stem cell transplantation (HSCT; n=7). Although early studies reported on the occurrence of LGL post-transplant, these studies focused on the analysis of oligoclonality skewed reactive CTL responses rather than frank T-LGLL. We aimed to characterize post-transplantation T-LGLL in SOT and HSCT simultaneously and compare them to a control group of 231 de novo T-LGLL (cases with no history of SOT or HSCT). To characterize an unambiguous "WHO-defined T-LGLL" we applied stringent and uniform criteria. All cases were diagnosed if 3 out of 4 criteria were fulfilled, including: 1) LGL count >500/µL in blood for more than 6 months; 2) abnormal CTLs expressing CD3, CD8 and CD57 by flow cytometry; 3) preferential usage of a TCR Vβ family by flow cytometry; 4) TCR gene rearrangement by PCR. In addition, targeted deep sequencing for STAT3 mutations was performed and charts of bone marrow biopsies were reviewed to exclude other possible conditions. Diagnosis was made 0.2-27 yrs post-transplantation (median: 4 yrs). At the time of T-LGLL diagnosis, relative lymphocytosis (15-91%), T lymphocytosis (49-99%) and elevated absolute LGL counts (>500 /µL; 93%) were also seen. Post-transplantation T-LGLL were significantly younger than de novo T-LGLL, (median age: 48 vs. 61 yr; P<.0001). Sixty% of post-transplantation T-LGLL patients were males. Fifteen% of patients had more cytogenetic abnormalities compared to de novo T-LGLL, had a lower absolute LGL count (median: 4.5 vs. 8.5 k/µL) and had less frequent neutropenia, thrombocytopenia and anemia (27 vs. 43%, 33 vs. 35% and 20% vs. 55%; P=.01). TCR Vb analysis identified clonal expansion of ≥1 of the Vb proteins in 60% (n=9) of the patients; the remaining 40% (n=6) of the cases had either a clonal process involving a Vb protein not tested in the panel (20%; n=3) or no clear expansion (20%; n=3). Signs of rejection were observed in 20% (n=3/15) and GvHD in 13% (n=2/15) of the patients. Post-transplantation, 27% of cases presented with neutropenia (absolute neutrophil count <1.5 x109/L; n=4), 33% with thrombocytopenia (platelet count <150 x109/L; n=5) and 25% with anemia (hemoglobin <10 g/dL; n=3). T-LGLL evolved in 10 patients (67%; 10/15) despite IST including cyclosporine (n=5), tacrolimus (n=4), mycophenolate mofetil (n=5), cyclophosphamide (n=1), anti-thymocyte globulin (n=1), and corticosteroids (n=6). Lymphadenopathy and splenomegaly were seen in 13% (n=2) and 33% (n=5) of the patients. Other conditions observed were MGUS (20%; n=3) and RA (7%; n=1). Conventional cytogenetic showed normal karyotype in 89% (n=11, tested individuals 13/15). Somatic STAT3 mutations were identified in 2 patients. Sixty% of cases (n=9) were seropositive for EBV when tested at different time points after transplant. Similarly, 53% (n=8) were seropositive for CMV, of which, 5 were positive post-transplantation and 3 pre-/post-transplantation. The complexity of T-LGLL expansion post-transplantation might be due to several mechanisms including active viral infections, latent oncogenic viral reactivation and graft allo-antigenic stimulation. However, in our cohort graft rejection or GvHD was encountered in a few patients (2 allo-HSCT recipients). Autoimmune conditions were present in 50% of SOT recipients (n=4/ 8, including RA, ulcerative colitis, systemic lupus erythematosus). Some of our patients also had low immunoglobulin levels. Overt EBV (post-transplant lymphoproliferative disorder) and CMV reactivation was diagnosed in only 27% (4/15) of the patients. In sum we report the long term follow up of a cohort of T-LGLL and emphasize the expansion of T-LGLL post-transplant highlighting the difficulty in assigning one unique origin of LGLL. Disclosures Hill: Genentech: Consultancy, Research Funding; Takeda: Research Funding; Celegene: Consultancy, Honoraria, Research Funding; Kite: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Seattle Genetics: Consultancy, Honoraria; Amgen: Research Funding; Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; TG therapeutics: Research Funding; AstraZeneca: Consultancy, Honoraria. Majhail:Atara Bio: Consultancy; Mallinckrodt: Honoraria; Nkarta: Consultancy; Anthem, Inc.: Consultancy; Incyte: Consultancy. Sekeres:Syros: Membership on an entity's Board of Directors or advisory committees; Millenium: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Maciejewski:Alexion: Consultancy; Novartis: Consultancy.

Impact Of The Early Intensification Of Induction Chemotherapy On Complete Remission and Survival Rates For De Novo Adult Acute Myeloid Leukemia

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3402-3402
Author(s):  
Seung-Ah Yahng ◽  
Jae-Ho Yoon ◽  
Sung-Eun Lee ◽  
Seung-Hwan Shin ◽  
Byung-Sik Cho ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Board Of Directors ◽  
Induction Chemotherapy ◽  
Myeloid Leukemia ◽  
Research Funding ◽  
De Novo ◽  
Remission Induction ◽  
Advisory Committees ◽  
Induction Regimen ◽  
Acute Myeloid

Abstract Background The successful induction chemotherapy of acute myeloid leukemia (AML) depends on the ability to achieve complete remission (CR) and to maintain remission status as long as possible. Approach to improve the rate of CR includes the intensification of induction chemotherapy for AML. The primary goal of this study was to evaluate and compare the long-term outcomes between remission induction therapy with and without early intensification added to the standard 3+7 remission induction regimen. Methods A retrospective analysis was performed on de novo AML patients diagnosed and treated at Catholic Blood and Marrow Transplantation Center between January 2001 and December 2010. Six hundred forty-one adults of ages between 16 and 60 were included, all of whom received induction chemotherapy starting with 3 days of idarubicin and 7 days of cytarabine or behenoyl cytarabine (BHAC). Cases with t(9;22) and t(15;17) were excluded. Bone marrow (BM) aspiration study was assessed on day 7 of induction in all patients. Factors which were considered for early intensification of induction were the presence of ≥ 5% BM blasts, patient performance, and other high risk clinical characteristics, such as karyotype. Groups according to early intensification on days 8 to 10 of induction were as followings: no intensification (3+7), n=156; cytarabine or BHAC for 3 days (3+10), n=233; addition of idarubicin for 2 days to 3+10 regimen (5+10), n=252. After a median duration of 5.5 months (3.3-19.0) from diagnosis, 479 patients underwent stem cell transplantation (autologous [auto-SCT], n=144; allogeneic [allo-SCT], n=335). Conditioning regimen for auto-SCT consisted of fractionated total body irradiation (TBI), melphalan, and cytarabine, whereas 83% (n=278) of patients with allo-SCT received myeloablative conditioning, of which was mostly TBI-based regimen (92%). Donors were matched sibling (n=213), matched unrelated (n=63), mismatched unrelated (n=39), and haploidentical related (n=20). Results The median age at diagnosis was 39 years (16-60). Mean values of BM blast % on day 7 of induction was 3.5 in 3+7 group, 7.9 in 3+10, and 33.6 in 5+10 (p=<0.0001), while no significant difference in the proportion of adverse karyotype was shown (11.7% vs. 12.8%, p=0.804). After first induction (3+7, n=165; 3+10/5+10, n=465), the CR/CRi rate was significantly higher in 3+10/5+10 versus 3+7 (78.1% vs. 69.2%, p=0.023), while the rate for death in aplasia was lower (4.3% vs. 9.6%, p=0.013). After re-induction with various regimens, the CR/CRi rate was still significantly higher in intensified group (p=0.012). The relapse rates between the groups in 536 patients achieving CR (83.6%), however, was not significantly different (8.9% vs. 9.9%, p=0.737). SCT was performed at CR1 (n=459), CR2 (n=10), or relapsed/refractory status (n=10). Patients with auto-SCT mostly had better/intermediate cytogenetic risk (96%) at diagnosis, while 12% of allo-SCT had poor karyotype. After the median follow-up duration of 60.2 months (2.2-143.5), the median overall survival (OS) in all patients (n=641) was 65.6 months. The 5-year disease-free survival (DFS) of patients with auto- and allo-SCT was 58.4±4.2 and 64.9±2.7, respectively. Of 334 patients receiving allo-SCT, the 5-year DFS was significantly higher in patients achieving CR1 (n=299) after first induction therapy (p<0.0001), in whom 75% of them had early intensification. Other factors with significant impact on DFS after allo-SCT (n=334) were karyotype at diagnosis (p=0.032) and donor type (HLA-matched vs. HLA-mismatched sibling or unrelated, 58.1%±3.8 vs. 45.1±8.0, p=0.016). The significances were confirmed in multivariate analysis, which demonstrated that achieving CR1 after first induction regimen and its maintenance until SCT was the most powerful predictor for DFS after allo-SCT (67.1±2.9 vs. 34.6±7.8, p=<0.0001). When all patients were analyzed, according to induction intensification, a statistically significant benefit in 10-year OS was observed in 5+10 intensified group (44.8% vs. 52.9%, p=0.032). Conclusion Our results suggest possible benefit of examining day 7 BM aspiration for the strategy of early intensification of induction chemotherapy for adult AML patients and our intensification doses can be safely added with high efficacy in the achievement of CR1 compared to 3+7 standard regimen, and may have affected for better DFS after allo-SCT. Disclosures: Kim: BMS: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Pfizer: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding.

Efficacy of Single-Agent Decitabine in Relapsed and Primary Refractory (rel/ref) Acute Myeloid Leukemia (AML)

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2518-2518
Author(s):  
Andrew Hantel ◽  
Niloufer Khan ◽  
Richard A. Larson ◽  
Lucy A. Godley ◽  
Michael J. Thirman ◽  
...  
Keyword(s):  
Board Of Directors ◽  
Genetic Risk ◽  
Research Funding ◽  
De Novo ◽  
Median Number ◽  
Advisory Committees ◽  
Secondary Aml ◽  
Induction Regimen ◽  
De Novo Aml ◽  
Wbc Count

Abstract Introduction Improving therapy for rel/ref AML remains a challenge. Decitabine, a DNA methyl-transferase inhibitor, initially showed promise in AML as a 5-day, first-line induction regimen and more recently as a 10-day regimen in older and unfit patients (1). However, little is known about the activity of decitabine in the rel/ref patient population despite increased use. Therefore, we sought to analyze the outcomes of these pts treated at our institution. Methods To obtain data regarding decitabine efficacy in rel/ref AML, we performed a retrospective analysis of outcomes following decitabine treatment in 34 adult pts treated at The University of Chicago from January 2009 to June 2014. Permission to access patient charts was granted by the medical centerÕs Institutional Review Board. AML was defined by WHO criteria, genetic risk grouping and complete remission (CR) was according to ELN classification; PR was defined as >50% decrease in bone marrow blasts and normalization of blood counts. Rel/ref AML was defined as either having had a prior CR with recurrence of disease or having received a prior induction regimen (1-2 cycles) without CR. Results Median pt age was 62 yrs (range, 18-81) and 60% were male. Median Charlson comorbidity index (CCI) was 5 (range, 0-8); 29% had ECOG performance status 0-1 and 71% had >2. 21 pts (62%) had de novo AML (7 with myelodysplasia-related changes), 3 (9%) had therapy-related myeloid neoplasm (t-MN), and 10 (29%) had secondary AML after myelodysplastic syndrome. 6% were in the ELN favorable genetic group, 3% intermediate-I, 18% intermediate-II, and 67% adverse; 2 cases were unevaluable. The median number of prior treatment regimens was three. 9% had received prior azacitidine, 85% had received prior HiDAC, and 38% had a prior allogeneic stem cell transplant (SCT). 34 pts received a total of 71 cycles of decitabine, 20 mg/m2 daily, in 5 or 10-day cycles every 28 days. All patients received 10-day courses, 91% had an initial 10-day course, and 74% had only 10-day courses. The median number of cycles per pt was 2; 59% received >1 cycle. 7 (21%) achieved CR and 4 (12%) had a partial response (PR), for an overall response rate (OR) of 33%. Responses occurred in 24% of pts with de novo AML, 66% with t-MN, and 50% with secondary AML. Intermediate and adverse group pts had OR of 14% and 39%, respectively. All pts achieving CR did so after 1 cycle; PR required a median of 3 cycles. Pts who achieved CR or PR had a significantly lower pretreatment WBC count (median, 9.5 vs 49.5 x 103/µL in non-responders; p=0.015) and blast percentage (44 vs 59.4; p=0.035) than those who did not. Pts with secondary AML or t-MN had a higher probability of OR compared to those with de novo AML (54 vs 23%; p=0.042). Median overall survival (OS) of all pts was 256 days; prior SCT was associated with reduced OS (p=0.017). When comparing de novo to secondary AML & t-MN, 1-year OS was not significantly different (Figure 1). Responders had a significantly longer OS (median, 622 days vs 278 days for non-responders; p=0.012). Age, race, CCI, ECOG PS, genetic risk group, prior HiDAC, dysplasia, azacitidine, and number of prior treatments did not impact OR or OS. 16 (47%) pts proceeded to SCT. During treatment, 70% had a grade 3-4 non-hematologic toxicity (based on NCI CTACE v4.0); the most common was fatigue. The median number of hospitalizations for complications per patient was 2 (range, 0-7). Causes of hospitalization were febrile neutropenia (40%), infection (22%), cytopenias (18%), rash (6%), acute kidney injury (6%), and 8% were for other causes. Conclusion Decitabine treatment of 34 adults with rel/ref AML resulted in an OR of 33% (21% CR) and allowed nearly one-half of these pts to proceed to SCT. All pts achieving CR did so after 1 cycle. Responding pts had improved OS over those without response (p=0.012). Interestingly, secondary AML or t-MN were 7.8 times more likely to achieve a response compared to de novo AML (p=0.046); lower WBC count and marrow blast percentage also correlated with higher OR. Further delineation of molecular subsets associated with response to decitabine should be evaluated in a larger prospective trial in this high-risk AML population. Citation 1. Blum KA, et al. Phase I trial of low dose decitabine targeting DNA hypermethylation in patients with chronic lymphocytic leukaemia and non-Hodgkin lymphoma: dose-limiting myelosuppression without evidence of DNA hypomethylation. Br J of Haem. Jul 2010;150(2):189-195. Figure 1. Figure 1. Disclosures Off Label Use: Decitabine is indicated for treatment of MDS but is often used to treat newly diagnosed or relapsed/refractory AML. In this study we analyzed results of patients with AML who were treated with decitabine in the relapsed/refractory setting.. Thirman:AbbVie: Research Funding; Pharmacyclics LLC, an AbbVie Company: Research Funding; Gilead: Research Funding; Merck: Research Funding; AbbVie: Research Funding; Gilead: Research Funding; Merck: Research Funding. Odenike:Sunesis: Membership on an entity's Board of Directors or advisory committees, Research Funding. Liu:Astra Zeneca/Medimmune: Consultancy; Pfizer: Consultancy; Astra Zeneca/Medimmune: Consultancy; Pfizer: Consultancy. Stock:Gilead: Membership on an entity's Board of Directors or advisory committees.

scholarly journals Determinants of "Fitness" for Intensive Therapy Among Acute Myeloid Leukemia (AML) Patients

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3836-3836
Author(s):  
Abby Statler ◽  
Brian P. Hobbs ◽  
Tomas Radivoyevitch ◽  
Caitlin Siebenaller ◽  
Sudipto Mukherjee ◽  
...  
Keyword(s):  
Board Of Directors ◽  
Research Funding ◽  
De Novo ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Advisory Committees ◽  
Cart Analysis ◽  
Cardiac Abnormalities ◽  
Oncology Research ◽  
Baseline Characteristics

Background: Determining which AML patients (pts) are "fit" for intensive chemotherapy (IC), both in real-world scenarios and for clinical trial eligibility (particularly as it relates to regulatory indications) is challenging. While age, AML etiology, and cardiac function have been invoked, these oversimplify the clinical assessment and recommendation for IC vs. Non-IC (NIC). We compared baseline characteristics among pts receiving IC and NIC, and evaluated associations between treatment receipt and pt characteristics. Adjusting for treatment received, pts' attributes were further evaluated for association with overall survival (OS). Methods: Adult (≥18 years) AML pts who received IC or NIC at Cleveland Clinic from 2003 to 2019 were included. The following characteristics were analyzed: age, sex, self-reported race, insurance, etiology of AML, comorbidities, hepatic and renal function tests, left ventricular ejection fraction (LVEF), and corrected QT interval (QTc). AML risk was categorized according to the 2017 European LeukemiaNet (ELN) risk stratification. Fisher's exact and Welch's t-tests were performed to compare baseline characteristics. Multivariate logistic and Cox regression were used to identify significant prognostic factors for treatment receipt and OS, respectively. The Kaplan-Meier method estimated distributions of OS, which were compared among pt cohorts using the log-rank test. Classification and regression tree (CART) analysis was performed to characterize the best decision process used to select pts for NIC. Results: Of 1,082 AML pts analyzed, 901 (83.2%) were treated with intensive, cytarabine-based chemotherapy, and 181 (16.8%) with non-intensive (low-dose cytarabine or hypomethylating agents) regimens. As expected, baseline characteristics were significantly imbalanced between groups; pts receiving NIC were more likely to be older (P<.001), have ≥3 comorbidities (P<.001), another cancer (P=.02), myocardial (P<.001), renal (P=.006) conditions, abnormal renal (creatinine (P=.004), creatinine clearance by Cockcroft-Gault (CrCl, P<.001)), and abnormal liver function (bilirubin (P=.03)). And less likely to have de novo disease (P<.001), favorable ELN risk (P=.008), private insurance (P<.001), and mild cardiac abnormalities (QTc 450-480ms (P<.001), LVEF 50-40% (P<.001)) (Tables 1 & 2). Multivariable stepwise regression revealed independent associations with the following attributes (favoring NIC over IC): older age (OR=1.10, P<.001), etiology (prior MDS vs. de novo; OR=2.52 , P<.001), liver (bilirubin >1.5xULN vs. normal; OR=3.04, P=.02), renal (CrCl <60 ml/min vs. normal; OR=3.17, P=.002), myocardial conditions (atrial fibrillation/congestive heart failure/coronary artery disease vs. normal); OR=2.33, P=.001) and mild cardiac abnormalities (QTc 450-480ms vs. normal: OR=0.46, P=.01; LVEF 50-40% vs. normal: OR=0.33, P=.03). Clinically, in making decisions about NIC, the first step is age, followed by comorbidity. CART analyses revealed that when a comorbidity is identified, age is then re-assessed; depending upon the type of comorbidity present, various age thresholds determined NIC vs. IC. With a median follow-up of 12.9 (IQR: 4.67-43.13) months, the median OS for the cohort was 15.1 months (range 0.03-189.25). OS was significantly different between groups (median OS, NIC vs. IC: 4.9 vs. 20.4 months, P<.001). In multivariate analyses controlling for treatment (IC vs. NIC), age, sex, insurance, number of comorbidities, AML etiology, and ELN risk, having another cancer (HR= 0.97, P=.78), renal (HR=1.10, P=.56) or myocardial comorbidity (HR= 0.94, P=.60) were not significantly associated with OS. Liver (bilirubin >1.5xULN: HR=1.70, P=.01), renal (creatinine >1.5xULN: HR=1.55, P=.001; CrCl<60ml/min: HR=1.37, P=.01), and cardiac dysfunction (QTc >480-500ms: HR=1.36, P=.04; LVEF 50-40%: HR=1.38, P=.04) were, however, associated with worse survival. Conclusions: Age, comorbidities, and organ dysfunction are associated with AML treatment determination. Pts who presented with cancer/renal/myocardial comorbidities and renal/liver dysfunction were more likely to receive NIC, despite the comorbid conditions not having an impact on OS. Further research needs to elucidate the extent to which NIC is the optimal treatment decision for pts exhibiting varying severities of cancer/renal/myocardial comorbidities. Disclosures Hobbs: SimulStat Inc.: Consultancy; Amgen: Research Funding. Mukherjee:McGraw Hill Hematology Oncology Board Review: Other: Editor; Partnership for Health Analytic Research, LLC (PHAR, LLC): Consultancy; Celgene Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Projects in Knowledge: Honoraria; Bristol-Myers Squibb: Speakers Bureau; Takeda: Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria. Advani:Glycomimetics: Consultancy, Research Funding; Amgen: Research Funding; Kite Pharmaceuticals: Consultancy; Macrogenics: Research Funding; Abbvie: Research Funding; Pfizer: Honoraria, Research Funding. Gerds:Sierra Oncology: Research Funding; Celgene Corporation: Consultancy, Research Funding; Pfizer: Consultancy; Incyte: Consultancy, Research Funding; CTI Biopharma: Consultancy, Research Funding; Imago Biosciences: Research Funding; Roche: Research Funding. Nazha:Daiichi Sankyo: Consultancy; Tolero, Karyopharma: Honoraria; MEI: Other: Data monitoring Committee; Novartis: Speakers Bureau; Jazz Pharmacutical: Research Funding; Incyte: Speakers Bureau; Abbvie: Consultancy. Sekeres:Millenium: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Syros: Membership on an entity's Board of Directors or advisory committees.

scholarly journals Exome Array Analyses Identify Low-Frequency Germline Variants Associated with Increased Risk of AML in a HLA-Matched Unrelated Donor Blood and Marrow Transplant Population

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 42-42
Author(s):  
Alyssa I. Clay ◽  
Theresa Hahn ◽  
Qianqian Zhu ◽  
Li Yan ◽  
Leah Preus ◽  
...  
Keyword(s):  
Board Of Directors ◽  
Research Funding ◽  
De Novo ◽  
Association Studies ◽  
Low Frequency ◽  
Hematologic Malignancies ◽  
Unrelated Donor ◽  
Advisory Committees ◽  
De Novo Aml ◽  
Normal Cytogenetics

Abstract Both genome wide association studies (GWAS) of common variation and exome wide association studies (EXWAS) of rare variation have successfully identified disease susceptibility variants for a variety of diseases. One GWAS of inherited susceptibility to Acute Myeloid Leukemia (AML) has been conducted, but no EXWAS have been performed to measure risk of AML attributable to low-frequency constitutional genetic variation. We performed the first EXWAS of risk of AML as a nested case-control study in the DISCOVeRY-BMT (Determining the Influence of Susceptibility Conveying Variants Related to one-Year mortality after BMT) cohorts. The DISCOVeRY-BMT parent study examined transplant-related mortality in leukemia patients undergoing unrelated donor allogeneic BMT. To identify low frequency variants and genes contributing to increased susceptibility to AML we used genotype data from the Illumina HumanExome BeadChip typed in the DISCOVeRY-BMT cohorts; the HumanExome BeadChip contains 242,901 variants, which are mainly protein-coding variants. The optimal sequence kernel association test (SKAT-O) was used to analyze gene-level associations with risk of AML. These gene-based tests evaluate the cumulative effects of multiple single gene variants on risk of AML. Analyses were performed in all European American AML cases and two subtypes: 1) de novo AML, 2) de novo AML with normal cytogenetics. Models were adjusted for age at transplant and principal components to control for population stratification. For gene-based tests at least 2 variants with minor allele frequency (MAF) ≤ 5%, were required to be present in the gene. This yielded a total of 13,687 genes tested, and a Bonferroni corrected significance level of P<3.65 x 10-6. Association tests were performed in 1,189 AML cases reported to CIBMTR 2000-08 (Cohort 1) and 327 AML cases reported to CIBMTR from 2009-11 (Cohort 2). Controls in Cohorts 1 (n=1,986) and 2 (n= 515) were 10/10 HLA-matched unrelated donors who passed a comprehensive medical exam and deemed healthy. We used metaSKAT to combine Cohorts 1 and 2 and obtain p-values of association with AML. We present the results of gene-level tests significant in both cohorts. The likely pathogenicity of these variants was determined in silico using SIFT, PolyPhen and MutationTaster. Patient characteristics are in Table 1. DNMT3A, on chromosome 2, was associated in the gene-based test with risk of AML (Pmeta=1.70x10-9, Table 2). Three missense variants at MAF <1% comprise both overall AML and de novo AML gene-based association: exm177559 (Asn->Ser), exm177507 (Arg->His), and exm177543 (Arg->Trp). Normal cytogenetics de novo AML gene-based assocations consisted of only 2 of these variants: exm177559 and exm177507 (Table 2). While prevalence of exm177507 is <1% for all AML cases, in de novo AML with normal cytogenetics the MAF was higher at 3%. The other 2 variants had a MAF<1% irrespective of subtype. Somatically, DNMT3A is most frequently mutated in hematologic malignancies, with >30% of de novo AML cases with a normal karyotype and >10% of MDS patients having DNMT3A mutations. Although these are germline gene associations all three of the variants found have been reported somatically in hematologic malignancies. In 200 AML cases from The Cancer Genome Atlas (TCGA) p.R882H (represented as exm177507 on the exome chip) was a frequent somatic mutation (25%). Exm177543 (p.R635W) and exm177559 (p.N501S) are reported in the Catalogue of Somatic Mutations in Cancer (COSMIC) as somatic mutations involved in hematopoietic and lymphoid tissue in both cell lines and humans. Exm177507 and exm177543 show evidence of pathogenicity in all three in silico tools, while exm177559 was reported as deleterious and disease causing by Sift and MutationTaster, respectively. Our results show that multiple potentially pathogenic missense germline variants in DNMT3A comprise the gene-based association with AML, specifically de novo AML with normal cytogenetics. Given the functional nature of these variants it is possible germline risk stratification could be informative in determining AML risk, and subsequently development of AML harboring DNMT3A mutations. Confirmation of these findings in additional cohorts could have implications for individualized risk screening, prediction and prognosis. Additional cytogenetic subgroup analyses, including treatment-related AML, are underway. Disclosures Hahn: Novartis: Equity Ownership; NIH: Research Funding. McCarthy:Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Onyx: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; The Binding Site: Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gamida Cell: Honoraria, Membership on an entity's Board of Directors or advisory committees. Sucheston-Campbell:NIH/NCI: Research Funding.

scholarly journals Ponatinib and Chemotherapy in Young Adults with De Novo Philadelphia Chromosome-Positive Acute Lymphoblstic Leukemia. Preliminary Results of Ponalfil Clinical Trial

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3874-3874
Author(s):  
Josep-Maria Ribera ◽  
Olga García ◽  
Pilar Martinez ◽  
Pau Montesinos Fernandez ◽  
Blanca Boluda ◽  
...  
Keyword(s):  
Board Of Directors ◽  
Research Funding ◽  
Kinase Inhibitors ◽  
De Novo ◽  
Philadelphia Chromosome ◽  
Molecular Response ◽  
Advisory Committees ◽  
Allogeneic Hsct ◽  
Preliminary Results ◽  
Central Artery

Background and objective. The combination of tyrosine kinase inhibitors (TKI) and chemotherapy (intensive, attenuated or minimal) has improved the prognosis of patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL). The combination of HyperCVAD and ponatinib has improved the molecular response and survival compared with other combinations of chemotherapy and first or second generation tyrosine kinase inhibitors (TKI) (Jabbour, et al, Lancet Haematol. 2018; 5:e618-e627). The Spanish PETHEMA group conducts the phase 2 PONALFIL trial, that incorporates ponatinib to the same induction and consolidation schedule of the ALL Ph08 trial (Ribera JM et al. Cancer 2019. doi:10.1002/cncr.32156). The preliminary results of this trial are herein reported. Patients and method. The PONALFIL trial (NCT02776605) combines ponatinib (30 mg/d) and induction chemotherapy (vincristine, daunorubicin and prednisone) followed by consolidation (high-dose methotrexate, ARA-C, mercaptopurine, etoposide) and allogeneic HSCT in de novo Ph+ ALL patients aged 18-60 years. Regular molecular follow-up was performed after alloHSCT. No TKI after HSCT was planned unless persistence or reappearance of molecular disease. On July 2019, 21 out of the 30 patients had been recruited. Molecular studies were centrally carried out according to the Euro-MRD consortium on standardization (Pfeifer et al, Leukemia, 2019; PMID: 30858550). The response to therapy (complete morphological [CR], molecular [complete, CMR or major, MMR] after induction and before allogeneic HSCT), CR duration, overall survival [OS]) and toxicity in the first 21 cases is herein analyzed. Results. Median age was 49 (19-59) years and 12 patients were female. One patient showed CNS involvement at diagnosis. Median WBC count was 12.4 (0.6-79.5) x109/L, Hb 87 (71-140) g/L, platelets 39 (15-180) x109/L. The immunologic phenotype was common in 13 cases, with molecular isoform p190 in 14 patients (67%), p210(b2a2) in 6 (21%) and p210(b3a2) in the remaining patient. CR was attained in 19/19 patients (2 are still on induction therapy), with CMR in 9/18 cases (50%), MMR in 4/18 (22%) and no molecular response in 5/18 (28%) (molecular response analysis pending in 1 patient). Six patients are receiving consolidation, 5 are waiting for allogeneic HSCT and 6 patients have been transplanted (4 in CMR, 1 in MMR, 1 with no data). At the time of the study one patient showed molecular relapse after allogeneic HSCT and is receiving ponatinib, whereas the remaining patients are alive and in CR1 (median follow-up of 3.7 months, range 0.3-18.2) Sixty-nine adverse events (AE) have been registered in 9 patients, 8 of whom were severe (SAE) and occurred in 6 patients, prompting to withdrawn of the trial in 2 (thrombosis of the retinal central artery and severe bowel infection, one case each). The most frequent AE were hematologic (25%), gastrointestinal (14%), infections (7%), and cutaneous (7%). Cardiovascular events occurred in 2 patients (angor pectoris and thrombosis of central artery of the retina, one case each). Conclusions. The preliminary results of the PONALFIL trial show a high short-term antileukemic efficacy with acceptable toxicity profile. Disclosures Fernandez: Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Teva: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Esteve:Pfizer: Consultancy; Novartis: Consultancy, Research Funding, Speakers Bureau; Celgene: Consultancy, Speakers Bureau; Amgen: Consultancy; Daiichi Sankyo: Consultancy; Jazz Pharmaceuticals: Consultancy; Roche: Consultancy; Astellas: Consultancy, Speakers Bureau. Bermúdez:Fresenius: Consultancy, Membership on an entity's Board of Directors or advisory committees; MSD: Consultancy, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees.

High Dose Imatinib Induction Therapy (800 mg/day, 6 Months) In Pre-Treated Chronic Phase CML Patients Improves Cytogenetic and Molecular Responses but Does Not Improve Overall and Progression Free Survival – Final Results of the CELSG Phase III CML11 “ISTAHIT” Trial

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2271-2271
Author(s):  
Andreas L Petzer ◽  
Dominic Fong ◽  
Thomas Lion ◽  
Irina Dyagil ◽  
Zvenyslava Masliak ◽  
...  
Keyword(s):  
Board Of Directors ◽  
Induction Therapy ◽  
Research Funding ◽  
De Novo ◽  
Chronic Phase ◽  
Phase Iii ◽  
High Dose ◽  
Molecular Response ◽  
Advisory Committees ◽  
Grade 3

Abstract Abstract 2271 Introduction: Imatinib 400 mg/day represents the current standard treatment for de novo as well as pre-treated CML patients in chronic phase (CP). Recent randomized phase III trials revealed conflicting results concerning the potential higher efficacy of dose-increased imatinib in de novo treated CP-CML. Methods: We here present the final analyses including response data, OS, EFS and PFS of the multicenter, randomised, 2-arm phase III CELSG “ISTAHIT” trial evaluating imatinib high dose (HD) induction (800 mg/day, 6 months) followed by 400 mg/day as maintenance (experimental arm B) compared to continuous imatinib standard dose (400mg/day; arm A) in pre-treated CP CML patients. ClinicalTrials.gov Identifier: NCT0032726. Results: From a total of 243 patients screened for inclusion, 16 patients were not eligible (mainly due to non sufficient numbers of metaphases obtainable from the bone marrow before the start of the study). Of the remaining 227 patients, 113 patients were randomized into arm A and 114 patients into the experimental arm B. Subsequent data are presented as per protocol. No significant differences between treatment groups were observed regarding sex (55.5% female, 44.5% male), age (median: 46.3 years, range 18 –76), Sokal scores at diagnosis (30% low, 41% intermediate, 16% Sokal high risk, 13% unknown) and different pre-treatments, which included hydroxyurea (96%), interferon (72%), busulfan (17%) and “others” (26%; mainly Ara-C). The median observation time was 673 days. Cytogenetic responses were generally higher in the experimental arm B and revealed statistically significant differences in major cytogenetic responses (MCyR) at 3 and 6 months (month 3: 25.8% arm A, 48.3% arm B, p=0.002; month 6: 41.9% arm A, 58.8% arm B, p=0.029) as well as in complete cytogenetic responses (CCyR) not only during imatinib HD therapy (month 3: 7.5% arm A, 29.9% arm B, p<0.001; month 6: 20.4% arm A, 47.4% arm B, p<0.001) but also thereafter (month 12: 31.8% arm A, 52.9% arm B, p=0.006). The primary endpoint of the study, the achievement of an improved MCyR at 12 month was, however, not significantly different (56.8% arm A, 64.4% arm B). In line with improved cytogenetic responses, major molecular response (MMRIS) rates were also significantly better at 3, 6 and even at 24 months in the HD arm B (month 3: 3.7% arm A, 15.9% arm B, p=0.003; month 6: 9.4% arm A, 34.6% arm B, p<0.001; month 24: 26.5% arm A, 42.5% arm B, p=0.034). Surprisingly, however, this impressing improvement in cytogenetic and molecular remissions in patients achieving high dose imatinib as induction therapy did not translate into a better OS and PFS, both of which were comparable in the two treatment arms (OS: p=0.25; EFS: p=0.37). Moreover, the EFS was even significantly worsened in the experimental arm B (p=0.014). Grade 3/4 non-haematological toxicities during the first 6 months of therapy were comparable, whereas grade 3/4 haematological toxicities were significantly more common in the imatinib HD arm B. Conclusions: Although high dose imatinib induction induces more rapid and higher cytogenetic and molecular remission rates in pre-treated CP CML patients, OS as well as PFS were not improved and EFS was even worsened in the high dose induction arm B. Therefore we conclude that imatinib 400mg/day remains the standard of care for pre-treated CP-CML patients. Disclosures: Petzer: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Off Label Use: Imatinib 800mg is not licensed as the initial therapy of chronic phase CML. Lion: Novartis: Honoraria, Research Funding. Bogdanovic: Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Griskevicius: Novartis: Research Funding. Kwakkelstein: Celgene: Employment. Rancati: Novartis: Consultancy, Employment, Equity Ownership, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Gastl: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Wolf: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees.

The Effect of Eltrombopag on Platelet Resistance to Apoptosis: The Role of the Bcl-Xl Pathway

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1158-1158
Author(s):  
W. Beau Mitchell ◽  
Michele N Edison ◽  
Mariana P Pinheiro ◽  
Nayla Boulad ◽  
Bethan Psaila ◽  
...  
Keyword(s):  
Platelet Count ◽  
Board Of Directors ◽  
Research Funding ◽  
De Novo ◽  
Apoptosis Resistance ◽  
Advisory Committees ◽  
Apoptotic Pathway ◽  
Akt Activation ◽  
Platelet Counts ◽  
Equity Ownership

Abstract Abstract 1158 INTRODUCTION: Immune thrombocytopenia (ITP) is typically characterized by increased platelet destruction and reduced platelet production. Eltrombopag and Romiplostim are thrombopoietin receptor (TPO-R) agonists that are known to increase platelet counts in patients with ITP by stimulating thrombopoiesis. Platelets also express TPO-R on their surface, but it is unknown whether the thrombopoietin mimetics (TPO-M) have a direct effect on the circulating platelets. Although controversial, in a very small number of ITP patients, TPO-M agents may increase platelet counts in 2–5 days, earlier than would be expected from de novo megakaryocytopoiesis. Platelet survival is hypothesized to be mediated by two molecular intermediates in an apoptotic pathway, Bcl-xL and Bak. Bcl-xL/Bak protein expression in megakaryocytes is regulated in part by TPO-mediated activation of Akt pathways through Jak2 and Stat5. We hypothesized that an increase in platelet count in the first week of treatment might be mediated by TPO-R signaling, resulting in decreased platelet apoptosis. This study explored whether Eltrombopag or Romiplostim treatment has anti-apoptotic effects on platelets of patients with ITP. METHODS: Following a treatment wash out period, 75 mg of Eltrombopag once daily or 10 mcg/kg weekly of Romiplostim was initiated for 2 weeks. Blood counts were measured on days 1, 3, 5, 8, 10, 12, and 15. Platelet function and survival was assessed on days 1, 8, and 15 by: immature platelet fraction (IPF), glycocalicin index, Bcl-xL inhibitor (ABT-737) assay, measurement of Bcl-xL by western blot, measurement of several members of the Bcl-xL Akt mediated, apoptotic pathway by flow cytometry (FACS), bleeding score, measurement of thrombin-anti-thrombin complexes (TATs), and quantification of microparticles. RESULTS: Eight of 10 patients responded to treatment with Eltrombopag with a platelet count ≥ 50,000/μL, and 6 of the 8 responders at least doubled their counts during the 2 weeks of treatment. All 3 patients treated with Romiplostim responded with platelet count ≥ 50,000/μL. In both treatment groups there was a significant increase in median platelet count (p<0.001), median large platelet count (p<0.01), and median absolute IPF (A-IPF, p<0.01), while there was no significant change in median % IPF. The dose of ABT-737 required to kill half of the platelets in the sample (IC50) in the Eltrombopag group was lower in patients at day 1 than in non-ITP controls, and there was an increase in resistance to apoptosis between days 1 and 8, but these changes did not reach statistical significance. Between days 8 and 15 the IC50 declined to pre-treatment levels. In the Romiplostim group there was no significant difference in IC50 between the control and the patients over the 2 weeks of study. There was no significant correlation between the platelet counts and the IC50 values. FACS analysis of members of the AKT signal transduction pathway revealed increased activation of each of the markers between days 1 and 8, followed by a decrease between days 8 and 15. The levels of Bcl-xL and phosphor-AKT(308) decreased from day 1 to day 15. The other lab tests are pending. DISCUSSION: Because the A-IPF increased by less than the platelet increase and because the lifespan of the A-IPF is not known, it is unclear if the platelet count increase is solely a result of increased platelet production. Platelet lifespan may be enhanced by Eltrombopag treatment as there was a parallel albeit transient increase in AKT activation markers and platelet apoptosis resistance in the Eltrombopag group. Treatment with Romiplostim did not appear to affect apoptosis resistance although it did result in transient AKT activation. Our data suggest that platelets are more resistant to apoptosis when the levels of anti-apoptotic factors (eg. PTEN, Phospho-GSK3β) involved in the AKT/Bcl-xL pathway are greatest despite a concomitant increase in pro-apoptotic factors (eg. Bak, Bax). Since both the increased AKT activation and apoptotic resistance returned to baseline at day 15, megakaryocytes and platelets already present at the start of treatment may respond differently than those generated de novo in the presence of TPO mimetics. 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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