Acute Myeloid Leukemia Myelodysplastic Syndrome Research Articles

Immune Checkpoint Inhibitor Therapy for Acute Myeloid Leukemia and Higher-Risk Myelodysplastic Syndromes: A Single-Center Experience

Immune Checkpoint Inhibitor Therapy for Acute Myeloid Leukemia and Higher-Risk Myelodysplastic Syndromes: A Single-Center Experience

Impact of Somatic Mutations and Pretransplant Strategies on the Outcome of Patients Allografted for MDS or Secondary AML

Introduction: In addition to other disease-, patient- and procedure-related factors, recent studies revealed a strong impact of somatic mutations on the outcome after allogeneic transplantation (allo-SCT) in patients with myelodysplastic syndromes (MDS) and secondary acute myeloid leukemia (AML). The choice of pre-transplant strategy (upfront transplantation [Tx] vs. induction chemotherapy [CTX] vs. hypomethylating agent [HMA]) is a matter of debate among experts but may also influence post-transplant outcome. The issue whether there is an interplay between mutational profile and pre-transplant therapies and how this may modulate outcome after allo-SCT has not been investigated so far and was therefore the scope of this analysis. Methods: For this purpose we performed amplicon-based sequencing (TruSight Myeloid 54-gene panel, Illumina®) of pre-transplant samples from 128 patients with MDS (85%) or sAML (15%) who had received an allo-SCT at our institution between 2001 and 2015 from related (46%) or unrelated (54%) donors following standard-dose (39%) or reduced-intensity (61%) conditioning. Seventy-three patients (57%) were directly transplanted (upfront group), while 55 patients (43%) had received pre-transplant cytoreductive therapy (CTX or HMA). Molecular data, pre-transplant therapy and clinical variables were entered into uni- and multivariate analyses to estimate their impact on outcome after allo-SCT and response to salvage therapy in patients relapsing after allo-SCT. Results: Estimated 5-year overall (OS) and relapse-free survival (RFS) of the entire cohort was 56% and 42%, respectively. Corresponding to the presence of at least one mutation in 87% of patients (median 2 mutations per patient, range 0-6) a total of 285 mutations were detected, with RUNX1 (18%), ASXL1 (17%), SRSF2 (15%), DNMT3A (13%), TET2 (13%), TP53 (12%) and SF3B1 (10%) being the most frequently affected genes. Multivariate modeling revealed independent negative prognostic impact of TP53 and SF3B1 mutations on OS, RFS and cumulative incidence of relapse (CIR); NRAS and DNMT3A mutations on OS; as well as NRAS and SF3B1 mutations on non-relapse mortality. Similar to the non-transplant setting, these 4 "poor risk" mutations refined the prognostication of patients with complex karyotype, since those carrying at least one of the "poor-risk" mutations had an even worse prognosis. In addition, pre-transplant cytoreductive therapy negatively influenced not only OS, RFS and CIR after allo-SCT in multivariate analysis, but also interacted with mutations status. Indeed, patients receiving upfront Tx had the best outcome in terms of OS and RFS in the absence of "poor risk" mutations. In the presence of any of these 4 mutations, prognosis of patients receiving upfront TX was worse, but still significantly better compared to patients carrying a "poor risk" mutation who had undergone pre-transplant cytoreduction (Figure 1). The negative impact of these mutations detected prior to transplant was abrogated after transplant in 41 relapsed patients treated with HMA+/-DLI. Pre-transplant strategy also significantly influenced outcome after HMA-based salvage therapy, as patients in the upfront group had a higher likelihood of response and survival. Conclusion: These results confirm and expand previous data on the prognostic impact of mutations in TP53, SF3B1, DNMT3A and NRAS on outcome after allo-SCT. There seems be a prognostic interaction between mutational status and pre-transplant strategy, suggesting that it may be possible to adapt pre-transplant therapy according to the molecular profile of each patient. Figure 1 Disclosures Rautenberg: Jazz Pharmaceuticals: Other: Travel Support; Celgene: Honoraria, Other: Travel Support. Germing:Novartis: Honoraria, Research Funding; Jazz Pharmaceuticals: Honoraria; Celgene: Honoraria, Research Funding; Amgen: Honoraria. Gattermann:Alexion: Research Funding; Novartis: Honoraria; Takeda: Research Funding. Kobbe:Celgene: Honoraria, Other: Travel support, Research Funding; Jazz: Honoraria, Other: Travel support; Medac: Honoraria, Other: Travel support; Roche: Honoraria, Other: Travel support; Amgen: Honoraria, Other: Travel support, Research Funding; Biotest: Honoraria, Other: Travel support; Novartis: Honoraria, Other: Travel support; Neovii: Honoraria, Other: Travel support; MSD: Honoraria, Other: Travel support; Pfizer: Honoraria, Other: Travel support; Takeda: Honoraria, Other: Travel support; Abbvie: Honoraria, Other: Travel support. Schroeder:Celgene Corporation: Consultancy, Honoraria, Research Funding.

Immunomodulation with Azacytidine and Donor Lymphocyte Infusion Following Sequential Conditioning Allogenic Stem Cell Transplantation Improves Outcome of Unfavorable AML

Background : Patients with acute myeloid leukemia in relapse or refractory to induction therapy have dismal prognosis. Response rates to common salvage regimens are low and allogenic hematopoietic stem cell transplantation is the only curative option. Several studies have demonstrated that salvage chemotherapy with sequential conditioning could reduce leukemia relapse risk with an acceptable toxicity profile for unfavorable acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). [1] Therefore, we decided to assess this procedure in our center at Amiens University Hospital. Methods We conducted a monocentric retrospective study, including 53 patients aged over 18 years undergoing a hematopoietic stem cell transplant (HSCT) with sequential conditioning between January 2012 and December 2018, for relapse/refractory AML or high risk MDS. 44 (83%) patients received sequential conditioning containing clofarabine (SET-RIC) or Amsacrine (FLAMSA) and 9 (17%) thiotepa based (TEC-RIC) with post-transplant cyclophosphamide for mismatched donors. Patients who were GVHD free after immunosuppressors withdrawal received immunomodulation as relapse prevention with azacytidine 37.5mg/m²/day 5 days every 4 weeks for 12 cycles with 3 donor lymphocyte infusions (DLI) alterned between azacytidine cycles. Results The median age was 52 years (range 18-70). Before conditioning, 48 patients had unfavorable AML with ELN intermediate score refractory to at least one course of induction therapy or in relapse, or unfavorable ELN score; 5 patients had high risk MDS with complex karyotype. 32 patients (60,5%) had active disease and 21 (39,5%) were in complete remission (CR) including 12 with positive MRD. 13 (24,5%) patients had HLA-identical sibling donors, 27 (51%) match unrelated donors (MUD), 4 (7,5%) mismatch unrelated donors (MMD) and 9 (17%) haploidentical donors. Majority of patients (90,5%) received peripheral blood stem cell (PBSC) PBSC with median CD34+ count of 7,94.106/kg (1,84-8,44). Acute GvHD prophylaxis with Ciclosporin A, in combination with Mycophenolate mofetil for MUD/MMR/Haplo, was withdrawal with a median time of 90 days. With a median follow-up of 40 months, overall survival (OS) at 1 and 2 years was 68% and 52%. Median OS was 18,7 months (0-72,4 months) and median disease free survival (DFS) was 14,9 months (0-72,4 months). 17 patients (32%) experienced relapse after HSCT with a median time from HSCT to relapse of 6 months (1-35 months). 22 (41,5%) of patients presented with grade I-II acute graft versus host disease (GVHD) and 6 (11,3%) with grade III IV aGVHD . GVHD free relapse free survival (GRFS) at 1 and 2 years was 53% and 34,2%. One-year cumulative incidence of disease related death and non-relapse mortality was 12,6% and 17% respectively. 19 patients received immunomodulation with 5 Azacitidine and DLI if no GVHD occurred within day 120. OS was 79 % in the 19 patients receiving DLI. In univariate analysis immunomodulation post HSCT (Figure 1) was significantly associated with overall survival and leukemia free survival (p=0,0164 and p=0,0359 respectively) but not the disease status before HSCT (p=0,7). Immunomodulation administration with azacytidine and DLI was not significantly associated with cGVHD occurrence (p=0.31). Benefit of immunomodulation OS persisted in multivariate analysis (p=0.0284). Conclusion: Sequential conditioning regimen on refractory AML with secondary immunomodulation with azacytidine and DLI shows very good results with an acceptable toxicity profile in unfavorable AML. We achieve very good OS and DFS whatever disease status before HSCT. GRFS is also encouraging comparing to previously report datas [1]. Reference: [1] Similar outcome of allogeneic stem cell transplantation after myeloablative and sequential conditioning regimen in patients with refractory or relapsed acute myeloid leukemia: A study from the Société Francophone de Greffe de Moelle et de Thérapie Cellulaire. Decroocq et al. Am J Hematol 2018 ;93 :416-423. Figure 1 Disclosures No relevant conflicts of interest to declare.

Dose Escalation Study of BET Inhibitor PLX2853 in Patients with Relapsed or Refractory Acute Myeloid Leukemia or High Risk Myelodysplastic Syndrome

Background: PLX2853 is an orally available, non-benzodiazepine BET (bromodomain and extraterminal domain) inhibitor that exhibits low nanomolar potency and a modest preference for binding to the second bromodomain (BD2) of the BET proteins. By regulating genes (e.g. MYC and BCL2) critical to leukemic cell growth and survival, PLX2853 demonstrated broad anti-leukemic activity both as a single agent and in combination with other therapeutic agents in preclinical models. The pharmacokinetic (PK) profile in solid tumor patients revealed a short half-life (< 3 hour) enabling high peak plasma concentrations and nearly complete elimination from the plasma 9 hour post dose. Since strong and prolonged suppression of BET proteins have often untoward effects in normal tissues, the PLX2853 PK profile is hypothesized to be associated with improved tolerability by allowing transient target engagement followed by time for recovery after daily dosing. Methods: We are conducting an open-label, Phase 1b (Ph1b) study of PLX2853 as a single oral agent administered daily in adult patients with relapsed or refractory acute myeloid leukemia (AML) or high risk myelodysplastic syndrome (MDS) using a modified continuous reassessment model (mCRM) with escalation with overdose control (EWOC) to determine the recommended phase 2 dose (RP2D). Up to 36 patients are expected to enroll. The dosing cycle and dose limiting toxicity window (DLT) is 21 days. Primary objectives include safety and PK. Secondary objectives include measures of preliminary efficacy, and exploratory objectives include pharmacodynamics (PD) biomarker assessments in various tissues. Enrollment through Cohort 2 (40 mg QD) is ongoing as of July 2019. Results: Five subjects with relapsed or refractory AML (median age 65 years) have received PLX2853 in escalating doses from 20 to 40 mg QD. Among these first 5 patients treated, the most common treatment emergent adverse events (AEs) regardless of causality in > 1 patient: decreased appetite (n=3), nausea (n=2), diarrhea (n=2), peripheral edema (n=2), cough (n=2), oropharyngeal pain (n=2), blood bilirubin increase (n=2), anemia (n=2), febrile neutropenia (n=2), fatigue (n=2), bacteremia (n=2), headache (n=2), dyspnea (n=2), and hypertension (n=2). Most were grade (G) 1-2. Treatment emergent AEs > G2 in > 1 patient included: anemia (n=2), febrile neutropenia (n=2) and hypertension (n=2). No treatment-related serious AEs or DLTs have been observed. Following a 20 mg daily dose of PLX2853, median time to reach maximal plasma concentrations (Tmax) is 1 hour and the absorption half-life (T1/2) is < 3 hours. Conclusions: In an ongoing Ph1b study, PLX2853 has now completed its first dosing cohort for patients with relapsed or refractory AML or high risk MDS, and no DLT has been observed yet. As dose escalation continues, PK, PD, preliminary safety and efficacy data will be assessed further to determine the clinical significance of target engagement. This clinical trial is registered at clinicaltrials.gov: NCT03787498. Disclosures Pemmaraju: mustangbio: Consultancy, Research Funding; abbvie: Consultancy, Honoraria, Research Funding; samus: Research Funding; celgene: Consultancy, Honoraria; cellectis: Research Funding; Stemline Therapeutics: Consultancy, Honoraria, Research Funding; novartis: Consultancy, Research Funding; plexxikon: Research Funding; Daiichi-Sankyo: Research Funding; sagerstrong: Research Funding; affymetrix: Research Funding; incyte: Consultancy, Research Funding. Borate:Novartis: Consultancy; Takeda: Consultancy; Pfizer: Consultancy; Daiichi Sankyo: Consultancy; AbbVie: Consultancy. Solh:ADC Therapeutics: Research Funding; Amgen: Speakers Bureau; Celgene: Speakers Bureau. Borthakur:Polaris: Research Funding; Arvinas: Research Funding; Agensys: Research Funding; Tetralogic Pharmaceuticals: Research Funding; Cantargia AB: Research Funding; Argenx: Membership on an entity's Board of Directors or advisory committees; BioLine Rx: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncoceutics, Inc.: Research Funding; Eli Lilly and Co.: Research Funding; BMS: Research Funding; AstraZeneca: Research Funding; Bayer Healthcare AG: Research Funding; Novartis: Research Funding; FTC Therapeutics: Membership on an entity's Board of Directors or advisory committees; AbbVie: Research Funding; Strategia Therapeutics: Research Funding; Cyclacel: Research Funding; Xbiotech USA: Research Funding; Eisai: Research Funding; Merck: Research Funding; BioTheryX: Membership on an entity's Board of Directors or advisory committees; Oncoceutics: Research Funding; NKarta: Consultancy; Incyte: Research Funding; Janssen: Research Funding; GSK: Research Funding; PTC Therapeutics: Consultancy. DeZern:Astex Pharmaceuticals, Inc.: Consultancy; Celgene: Consultancy. Zhang:Plexxikon Inc.: Employment. Powell:Plexxikon Inc.: Employment. Severson:Plexxikon Inc.: Employment. Inokuchi:Plexxikon Inc.: Employment. Matusow:Plexxikon Inc.: Employment. Halladay:Plexxikon Inc.: Employment. Hsu:Daiichi Sankyo, Inc.: Employment. Watkins:Plexxikon Inc.: Employment. Walling:Myovant Sciences: Consultancy; Nurix: Consultancy; Aduro Biotech: Consultancy; Plexxikon: Consultancy; CytomyX: Consultancy; Flag Therapeutics: Consultancy; Aminex: Consultancy; Immunext: Consultancy; SensenBio: Consultancy; Harpoon Therapeutics: Consultancy. Tsiatis:Plexxikon Inc.: Employment. Mims:PTC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Astellas Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Agios Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees.

Efficacy and Safety of a FLAG-Sequential Regimen Followed By Hematopoietic Stem Cell Transplantation for Myelodysplasia or Acute Leukemia in Fanconi Anemia: A Franco-Brazilian Report

Background: Fanconi anemia (FA) is the most frequent genetic cause of bone marrow failure (BMF) due to a DNA repair mechanism defect. The natural history of FA is marked by progressive BMF during early childhood. Throughout life, the hematopoietic situation may change by clonal evolution toward myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML). Hematopoietic stem cell transplantation (HSCT) is the only curative treatment for bone marrow failure in FA patients. The role of HSCT for FA patients with AML or advanced MDS is less defined. Currently, HSCT first line result offers 50% Overall Survival (OS) for patients with cytogenetic abnormalities only and 30% OS for patients with advanced MDS or AML in FA (Ayas et al., JCO 2013; Mitchell et al., BJH 2014). We previously reported a FLAG-sequential approach in 6 patients with FA (5 AML and 1 advanced MDS), all alive at a median follow-up of 28 months (Talbot et al., Hematologica 2014). We update here those patients and report 12 more patients treated by FLAG-sequential since then. Materials & Methods: This retrospective study (2006-2019) was conducted in 7 centers in France and Brazil on behalf of the French Reference Center for Aplastic Anemia to evaluate FLAG-sequential in FA patients with morphological clonal evolution (no patients with cytogenetic abnormalities only). The study was conducted in accordance with the Declaration of Helsinki. Anonymous data collection was declared to the appropriate authorities. The FLAG-sequential treatment consisted of FLAG, Fludarabine 30 mg/m²/d for five days and Cytarabine 1 g/m²x2/d with G-CSF for five days, which was followed three weeks later by Cyclophosphamide 10 mg/kg/d for four days, Fludarabine 30 mg/m²/d for four days and TBI 2 Gy (Fig 1A). In a haploidentical setting, Cyclophosphamide at 30 mg/kg/d was performed only in post-transplantation, at Days +4 and +5 (Fig 1B). Results: Eighteen patients were included with 14 AML, 1 acute lymphoblastic leukemia (ALL), and 3 RAEB-2 (Table 1). The median age at the time of HSCT was 22 years (4-37 years). Fifteen patients (83%) were older than 10 years at the time of HSCT. The median follow-up was 31 months (3- 153 months). Eight patients (44%) had complex karyotype. None of the included patients had a history of solid malignancies before HSCT. All patients engrafted. The cumulative incidence of neutrophil engraftment at Day 60 was 94% (95% CI 63-100%) with a median of 18 days (12-343 days). The cumulative incidence of platelet engraftment at Day 60 was 83% (95% CI 50%-96%) with a median of 25 days (17-245 days). The donor chimerism was complete at Day +100 for 15 patients. The three patients without full donor chimerism at Day +100 either had a relapse (n=1) and 2 early deaths before Day+100 from steroid-refractory aGVHD (n=1) or septic shock (n=1). None of the patients received a second HSCT. Non-relapse mortality (NRM) at 3 years was 32% (95% CI 6-58%) (Fig 2). Cumulative incidence of grades II to IV aGVHD was 56% (35% grades III to IV). Cumulative incidence of extensive cGVHD was 16%. Infectious complications during HSCT include the following: CMV (n=8), EBV (n=2), adenovirus (n=4), BK virus (n=7), respiratory syncytial virus (n=1), candidaemias (n=2) and invasive aspergillosis (n=3). Progression free survival (PFS) and OS at 3 years were 53% (95%CI 32-89%) and 53% (95%CI 32-89%), respectively (Fig 2). Cumulative incidence of relapse at 3 years was 13% (95%CI 0-31%) (Fig 2). Seven patients died during the study. Causes of death were relapse (n=2), aGVHD (n=2), cGVHD (n=1), septic shock (n=1), and respiratory syncytial virus associated with invasive aspergillosis (n=1). GVHD-relapse free survival (GRFS) at 3 years was 48% (95%CI 29-78%). One patient had anal epidermoid carcinoma at 4 years after HSCT, which required multiple surgical ablations. Conclusion: With almost 3 years follow-up, which is long enough for our results to be considered robust, we report an OS and PFS of 53%, which compares favorably to historical controls since all of our 18 patients were treated with florid disease at time of HSCT (and not with cytogenetic abnormality only, known to be associated with a better prognosis). Toxicity is still a concern in this particular population of FA patients with notably a high rate of infectious complications. Future well designed prospective clinical trials will refine this sequential strategy, which appears promising in this particular difficult clinical situation. Disclosures Socie: Alexion: Consultancy. Peffault de Latour:Alexion: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Amgen: Research Funding.

Preliminary Results from a Phase II Study of the Combination of Pevonedistat and Azacitidine in the Treatment of MDS and MDS/MPN after Failure of DNA Methyltransferase Inhibition

Preliminary Results from a Phase II Study of the Combination of Pevonedistat and Azacitidine in the Treatment of MDS and MDS/MPN after Failure of DNA Methyltransferase Inhibition

PF773 LOWER SERUM LEVELS OF ZINC AND MAGNESIUM ARE ASSOCIATED WITH WORSE ORAL CGVHD AND DYSGEUSIA IN CGVHD PATIENTS

Background: Acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) are hematological malignancies predominantly occurring in elderly patients. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the curative therapy for refractory AML or high risk MDS, but old age had been a limitation to access the eligibility for allo-HSCT. Seldom studies investigate the outcomes associated pre-transplant risk evaluations for elderly patients undergoing allo-HSCT. Aims: We conducted a retrospective study to research the practical pre-transplant risk stratification and identify the prognostic factors predicting outcomes of elderly patients with allo-HSCT for acute leukemia and MDS. Methods: By reviewing Taiwan Bone Marrow Transplantation registry data, we collected the clinical features of patients diagnosed with AML or MDS, who underwent allo-HSCT at age older than 50 years old from April 2011 to January 2018. Clinical characteristics including age, gender, type of allogeneic transplant, underlying disease, conditioning regimens, Charlson comorbidity index (CCI), donors’ age and presence of acute graft-versus-host disease (aGVHD) or chronic GVHD (cGVHD) were collected and analyzed. Cox proportional hazard model was adopted to explore the independent prognostic factors for overall survival (OS), and non-relapse mortality (NRM). Results: A total of 255 elderly patients were included during study period and the median age at allo-HSCT was 57 years old. There were 203 (80%) patients receiving allo-HSCT for AML, and 143 (56%) recipients’ stem cell source were unrelated donors. 175 (69%) patients underwent non-myeloablative conditioning regimens and CCI ≥ 3 was noted in 97 (38%) patients. 40 (16%) cases developed grade III-IV aGVHD, while 44 (17%) had moderate to severe cGVHD. The significant prognostic factors associated with worse OS were CCI ≥ 3 (hazard ratio [HR] 1.77, 95% confidence interval [CI] 1.25–2.52; P = 0.001), and grade III-IV aGVHD (HR 3.23, 95% CI 2.16–4.83; P < 0.001). Similar finding in NRM analysis: CCI ≥ 3 (HR 1.78, 95% CI 1.09–2.90; P = 0.02), and grade III-IV aGVHD (HR 4.93, 95% CI 2.96–8.12; P < 0.001) were associated with higher NRM. To investigate the cGVHD effects on outcomes, we performed the OS analysis for elderly patients with survival after allo-HSCT > 100 days. The CCI ≥ 3 (HR 1.88, 95% CI 1.22–2.90; P = 0.004) and grade III-IV aGVHD (HR 2.73, 95% CI 1.62–4.62; P < 0.001) remained poor prognostic factors for OS, while mild cGVHD (HR 0.43, 95% CI 0.24–0.76; P = 0.004) was associated with better OS. Kaplan-Meier curve of OS according to CCI ≥ 3 were illustrated in Figure 1.Summary/Conclusion: We identify CCI ≥ 3 and grade III-IV aGVHD as poor prognostic factors for OS and NRM in elderly patients underwent allo-HSCT. Development of mild cGVHD may allow elderly patients to have better OS. Graft-versus-leukemia may have important influences on survival and disease control for elderly patients experiencing allo-HSCT. Carefully to evaluate elderly patients’ comorbidities before allo-HSCT is necessary and this cohort study suggests that CCI ≥ 3 predicts poor outcomes, mainly resulted from higher risk for NRM. Indicated patients determined by CCI before transplantation and careful management of GVHD after transplantation may help elderly patients with AML or MDS get better survival after allo-HSCT.

PF772 THE CHARLSON COMORBIDITY INDEX PREDICTS OUTCOMES FOR ELDERLY PATIENTS UNDERGOING ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR ACUTE MYELOID LEUKEMIA AND MYELODYSPLASTIC SYNDROME

Background:Acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) are hematological malignancies predominantly occurring in elderly patients. Allogeneic hematopoietic stem cell transplantation (allo‐HSCT) remains the curative therapy for refractory AML or high risk MDS, but old age had been a limitation to access the eligibility for allo‐HSCT. Seldom studies investigate the outcomes associated pre‐transplant risk evaluations for elderly patients undergoing allo‐HSCT.Aims:We conducted a retrospective study to research the practical pre‐transplant risk stratification and identify the prognostic factors predicting outcomes of elderly patients with allo‐HSCT for acute leukemia and MDS.Methods:By reviewing Taiwan Bone Marrow Transplantation registry data, we collected the clinical features of patients diagnosed with AML or MDS, who underwent allo‐HSCT at age older than 50 years old from April 2011 to January 2018. Clinical characteristics including age, gender, type of allogeneic transplant, underlying disease, conditioning regimens, Charlson comorbidity index (CCI), donors’ age and presence of acute graft‐versus‐host disease (aGVHD) or chronic GVHD (cGVHD) were collected and analyzed. Cox proportional hazard model was adopted to explore the independent prognostic factors for overall survival (OS), and non‐relapse mortality (NRM).Results:A total of 255 elderly patients were included during study period and the median age at allo‐HSCT was 57 years old. There were 203 (80%) patients receiving allo‐HSCT for AML, and 143 (56%) recipients’ stem cell source were unrelated donors. 175 (69%) patients underwent non‐myeloablative conditioning regimens and CCI ≥ 3 was noted in 97 (38%) patients. 40 (16%) cases developed grade III‐IV aGVHD, while 44 (17%) had moderate to severe cGVHD. The significant prognostic factors associated with worse OS were CCI ≥ 3 (hazard ratio [HR] 1.77, 95% confidence interval [CI] 1.25–2.52; P = 0.001), and grade III‐IV aGVHD (HR 3.23, 95% CI 2.16–4.83; P &lt; 0.001). Similar finding in NRM analysis: CCI ≥ 3 (HR 1.78, 95% CI 1.09–2.90; P = 0.02), and grade III‐IV aGVHD (HR 4.93, 95% CI 2.96–8.12; P &lt; 0.001) were associated with higher NRM. To investigate the cGVHD effects on outcomes, we performed the OS analysis for elderly patients with survival after allo‐HSCT &gt; 100 days. The CCI ≥ 3 (HR 1.88, 95% CI 1.22–2.90; P = 0.004) and grade III‐IV aGVHD (HR 2.73, 95% CI 1.62–4.62; P &lt; 0.001) remained poor prognostic factors for OS, while mild cGVHD (HR 0.43, 95% CI 0.24–0.76; P = 0.004) was associated with better OS. Kaplan‐Meier curve of OS according to CCI ≥ 3 were illustrated in Figure 1.Summary/Conclusion:We identify CCI ≥ 3 and grade III‐IV aGVHD as poor prognostic factors for OS and NRM in elderly patients underwent allo‐HSCT. Development of mild cGVHD may allow elderly patients to have better OS. Graft‐versus‐leukemia may have important influences on survival and disease control for elderly patients experiencing allo‐HSCT. Carefully to evaluate elderly patients’ comorbidities before allo‐HSCT is necessary and this cohort study suggests that CCI ≥ 3 predicts poor outcomes, mainly resulted from higher risk for NRM. Indicated patients determined by CCI before transplantation and careful management of GVHD after transplantation may help elderly patients with AML or MDS get better survival after allo‐HSCT.image

Inherited thrombocytopenia and platelet disorders with germline predisposition to myeloid neoplasia.

Advances in molecular genetic sequencing techniques have contributed to the elucidation of previously unknown germline mutations responsible for inherited thrombocytopenia (IT). Regardless of age of presentation and severity of symptoms related to thrombocytopenia and/or platelet dysfunction, a subset of patients with IT are at increased risk of developing myeloid neoplasms during their life time, particularly those with germline autosomal dominant mutations in RUNX1, ANKRD26, and ETV6. Patients may present with isolated thrombocytopenia and megakaryocytic dysmorphia or atypia on baseline bone marrow evaluation, without constituting myelodysplasia (MDS). Bone marrow features may overlap with idiopathic thrombocytopenic purpura (ITP) or sporadic MDS leading to misdiagnosis. Progression to myelodysplastic syndrome/ acute myeloid leukemia (MDS/AML) may be accompanied by progressive bi- or pancytopenia, multilineage dysplasia, increased blasts, cytogenetic abnormalities, acquisition of bi-allelic mutations in the underlying gene with germline mutation, or additional somatic mutations in genes associated with myeloid malignancy. A subset of patients may present with MDS/AML at a young age, underscoring the growing concern for evaluating young patients with MDS/AML for germline mutations predisposing to myeloid neoplasm. Early recognition of germline mutation and predisposition to myeloid malignancy permits appropriate treatment, adequate monitoring for disease progression, proper donor selection for hematopoietic stem cell transplantation, as well as genetic counseling of the affected patients and their family members. Herein, we describe the clinical and diagnostic features of IT with germline mutations predisposing to myeloid neoplasms focusing on mutations involving RUNX1, ANKRD26, and ETV6.

Shwachman-Diamond syndrome with clonal interstitial deletion of the long arm of chromosome 20 in bone marrow: haematological features, prognosis and genomic instability.

In Shwachman-Diamond syndrome (SDS), deletion of the long arm of chromosome 20, del(20)(q), often acquired in bone marrow (BM), may imply a lower risk of developing myelodysplastic syndrome/acute myeloid leukaemia (MDS/AML), due to the loss of the EIF6 gene. The genes L3MBTL1 and SGK2, also on chromosome 20, are in a cluster of imprinted genes, and their loss implies dysregulation of BM function. We report here the results of array comparative genomic hybridization (a-CGH) performed on BM DNA of six patients which confirmed the consistent loss of EIF6 gene. Interestingly, array single nucleotide polymorphisms (SNPs) showed copy neutral loss of heterozygosity for EIF6 region in cases without del(20)(q). No preferential parental origin of the deleted chromosome 20 was detected by microsatellite analysis in six SDS patients. Our patients showed a very mild haematological condition, and none evolved into BM aplasia or MDS/AML. We extend the benign prognostic significance of del(20)(q) and loss of EIF6 to the haematological features of these patients, consistently characterized by mild hypoplastic BM, no or mild neutropenia, anaemia and thrombocytopenia. Some odd results obtained in microsatellite and SNP-array analysis demonstrate a peculiar genomic instability, in an attempt to improve BM function through the acquisition of the del(20)(q).

MDS-associated mutations in germline GATA2 mutated patients with hematologic manifestations

Germline mutation in GATA2 can lead to GATA2 deficiency characterized by a complex multi-system disorder that can present with many manifestations including variable cytopenias, bone marrow failure, myelodysplastic syndrome/acute myeloid leukemia (MDS/AML), and severe immunodeficiency. Penetrance and expressivity within families is often variable. There is a spectrum of bone marrow disease in symptomatic cytopenic patients ranging from hypocellular marrows without overt dysplasia to those with definitive MDS, AML, or chronic myelomonocytic leukemia. Relatives of probands with the same mutations may demonstrate minimal disease manifestations and normal marrows. A comprehensive clinical, hematological and genetic assessment of 25 patients with germline GATA2 mutation was performed. MDS-associated mutations were identified in symptomatic GATA2 patients both with overt MDS and in those with hypocellular/aplastic bone marrows without definitive dysplasia. Healthy relatives of probands harboring the same germline GATA2 mutations had essentially normal marrows that were overall devoid of MDS-associated mutations. The findings suggest that abnormal clonal hematopoiesis is a common event in symptomatic germline mutated GATA2 patients with MDS and also in those with hypocellular marrows without overt morphologic evidence of dysplasia, possibly indicating a pre-MDS stage warranting close monitoring for disease progression.

Efficacy of Low-Dose Decitabine in the Early Relapse of AML/MDS after Allogeneic Hematopoietic Stem Cell Transplantation

Objectives: Retrospective analysis of the efficacy and adverse effects of low-dose Decitabine(DAC) in patients with early relapse of acute myeloid leukemia/myelodysplastic syndrome(AML/MDS) after allogeneic hematopoietic stem cell transplantation (allo-HSCT).Methods:Fifteen patients with AML/MDS, which were early recurrence after transplantation, received low-dose DAC treatment. The evidence of early recurrence included engraftment index(FISH detection of sex chromosomes, or STR) <95%, MRD (+), fusion gene positive or positive bone marrow blast cells (between 5%~10%). DAC was given (5-10) mg·m2-1·d-1×5 days, every 6∼8 weeks, a maximum for 8 cycles. The treatment outcome, adverse reaction and graft-versus-host disease (GVHD) were analyzed. Fifteen patients included 13 with AML,1 with MDS-RAEB-2, and 1 with chronic myelogenous leukemia (CMML).Results: The total complete remission (CR) rate was 66.67%(10/15), the Objective response rate (ORR) was 86.67% (13/15); 5 cases of relapse in the effective patients, in which 3 cases with PR was relapse eventually, and 2 CR patients has extramedullary recurrence and bone marrow relapse, respectively, the recurrence rate was 38.46%(5/13). Grade 3 and 4 hepatic dysfunction was 26.67%, Grade 3 and 4 hematological toxicities was 60%.Conclusion:low-dose of DAC was effective and safe in controlling early recurrence, reducing GVHD symptoms, reducing recurrence rate and prolonging patient survival time. DisclosuresNo relevant conflicts of interest to declare.

Clonal Suppression of TP53 Mutant MDS and Oligoblastic AML with Hypomethylating Agent Therapy Improves Overall Survival

Background Hypomethylating agent (HMA) therapy represents the standard of care for patients with higher risk myelodysplastic syndromes (MDS) although only 50% of patients respond to treatment. Recent evidence from molecular profiling through next-generation sequencing (NGS) in myeloid diseases has been conflicting as to the value of somatic mutations as a biomarker for response to HMA. In particular, there have been conflicting data on response rates and outcomes in TP53 mutant (MT) MDS and acute myeloid leukemia (AML) based on azacitidine versus decitabine (Welch et al., NEJM 2016; Garcia-Manero et al., NEJM 2017). However, the TP53 mutant cohorts in these studies were small (median 23 patients, range 13-39) and heterogeneous based on treatment status (treatment naïve versus relapse/refractory). Therefore, our goal was to characterize outcomes of TP53 mutant MDS patients who received frontline HMA therapy.Patients and MethodsTP53 MT MDS and oligoblastic AML (20-30% blasts) cases were retrospectively identified from the Moffitt Cancer Center MDS database. All patients had NGS of TP53 and up to 53 additional genes performed prior to the initiation of HMA. The lower limit of VAF detection was set at 5% and the minimum depth of coverage at each position was 500X. Clinical variables and outcomes of MDS patients were characterized at the time of sample procurement. Fisher's exact tests were used for comparative analyses. Kaplan-Meier curves were used to estimate overall survival (OS) and analyzed from the date of HMA initiation. Response rates and outcomes of TP53 MT patients were compared to a cohort of wildtype (WT) patients (n=63).Results From May 2013 to May 2018, a total of 71 patients with TP53 mutant MDS were identified with a median age of 68 years (39-82) and male predominance (66%). Fourteen patients (20%) had multiple mutations in TP53. Of the cohort, 82% of patients (n=58) were treated with azacitidine (88% (n=51) with AZA monotherapy; 12% (n=7) with AZA in combination (2 pts with lenalidomide and 5 pts with investigational agents)) with 18% (n=13) receiving decitabine. The median # of HMA cycles was 4 (range 1-33). Thirteen pts (18%) proceeded to allogeneic hematopoietic stem cell transplant (HSCT). Of the cohort, 18% (n=13) obtained complete remission (CR) with 39% (n=28) overall response rate (ORR). There was no difference in CR or ORR in pts treated with AZA vs DAC (P=0.24 and P=0.2, respectively). At a median follow up 20 months, the median OS of the entire cohort was 9.7 months. There was no difference in median OS between AZA vs AZA combo vs DAC (7.6 vs 15.2 vs 12.5 months; P = 0.44; Figure 1A). TP53 variant allele frequency (VAF > 20% vs ≤ 20%) was not predictive of outcomes to HMA (7.8 vs 10.4 months, P = 0.36).However, TP53 MT patients who had clonal response to HMA (i.e. VAF < 5%; n=19 (27%)) had improved OS (14.5 vs 7.5 months; HR 0.33, 95% CI 0.18 to 0.59; P = 0.001; Figure 1B). In multivariable analysis incorporating age, revised international prognostic scoring system (IPSS-R) category, HSCT status, or type of HMA, TP53 clonal clearance remained an independent covariate for improved OS (HR 0.34, 95% CI 0.16 to 0.72; P = 0.005). Pts who underwent HSCT (n=13) had a trend for improved OS (14.5 months vs 7.9 months; P = 0.09). Notably in transplanted pts who had serial TP53 NGS (n=7), pts who achieved a VAF < 5% had significant improved OS (16.3 months vs 8.9 months; P=0.03). Compared to higher risk MDS/AML TP53 WT patients treated with HMA, there was no difference in CR (18% vs 14% (P = 0.64) or ORR rates (39% vs 40%). In contrast, TP53 MT patients had significantly inferior OS with HMA therapy (9.7 vs 15.4 months; HR 2.14, 95% CI 1.32. to 3.27; P = 0.001; Figure 1C).Conclusion In this large cohort of higher risk MDS and oligoblastic AML pts who received frontline HMA therapy, TP53 MT patients have significantly inferior OS with no significant differences in response rates or outcomes by HMA. TP53 MT patients who achieve maximum clonal suppression with HMA treatment (i.e. VAF < 5%) have improved OS as well as improved outcome with HSCT. Novel therapy targeting TP53 mutation is needed to improve outcomes. [Display omitted] DisclosuresSallman:Celgene: Research Funding, Speakers Bureau. Sweet:Agios: Consultancy; Jazz: Speakers Bureau; Astellas: Consultancy; Phizer: Consultancy; Phizer: Consultancy; Astellas: Consultancy; Jazz: Speakers Bureau; Celgene: Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau; Agios: Consultancy; BMS: Honoraria; Celgene: Honoraria, Speakers Bureau; BMS: Honoraria. List:Celgene: Research Funding. Komrokji:Novartis: Honoraria, Speakers Bureau; Celgene: Honoraria, Research Funding; Novartis: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Celgene: Honoraria, Research Funding; Novartis: Honoraria, Speakers Bureau.

Results of a Phase 2, Open-Label Study of Idarubicin (I), Cytarabine (A) and Nivolumab (Nivo) in Patients with Newly Diagnosed Acute Myeloid Leukemia (AML) and High-Risk Myelodysplastic Syndrome (MDS)

Results of a Phase 2, Open-Label Study of Idarubicin (I), Cytarabine (A) and Nivolumab (Nivo) in Patients with Newly Diagnosed Acute Myeloid Leukemia (AML) and High-Risk Myelodysplastic Syndrome (MDS)

Diverse Landscape of TET2 Variants in MDS and AML

INTRODUCTION The TET2 (Ten‐Eleven Translocation 2) gene, located at chromosome 4q24.1, belongs to TET family of proteins that possesses the capacity of catalyzing the conversion of 5‐methylcytosine into 5‐hydroxymethylcytosine. It is considered to be a putative tumor suppressor gene during cancer initiation and development. TET2 mutations are extensively studied and reported in a variety of human hematological malignancies including acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), suggesting a crucial role of TET2 in the pathogenesis of blood cancers. The landscape of rare TET2 variants which may be of potential clinical relevance is not fully described. The landscape of TET2 variants from a large cohort of MDS and AML patients was explored. METHODS We analyzed data from bone marrow samples of 2634 patients with AML or MDS who presented at MD Anderson between the years 2012-2016. Seven hundred seventy seven patients were found to have TET2 variants that were not classifiable as known mutations. Two hundred sixty-three patients were diagnosed with MDS, 144 with secondary AML transformed from MDS, and 370 with AML without prior history of MDS. The coding regions of TET2 gene was analyzed by next-generation sequencing in the molecular diagnostics laboratory. Non-mutation variants were classified into 2 groups: 1) those reported as germline polymorphisms (GP) in population studies, literature or matched tumor-normal analysis on patients at MDACC; and 2) variants for which a germline versus somatic origin could not be determined unequivocally (variants of uncertain origin, VUO). Very common GP variants (defined as those with a population frequency of over 20% in laboratory sample cohort) were not evaluated. Variants9 predicted frequency in the population according to gnomAD Exomes 2.0.2, and classification according to American College of Medical Genetics and Genomics (ACMG) guidelines for interpretation of sequence variants, were assessed using the VarSome platform by Saphetor. RESULTS Two-hundred and twenty-eight unique variants were identified. The amino acid substitutions from missense variants were widely distributed throughout TET2. Fifty-four unique variants were classified as GP and several of these recurrent variants were found to be present in our population at a significantly higher frequency (p CONCLUSIONS The landscape of rare TET2 variants in a large group of MDS and AML patients was frequent, diverse, and included both GP and VUO. GP variants were more likely benign by ACMG classification and found in both MDS and AML patients. A large number of singleton VUO were found among MDS patients, and many were predicted to be pathogenic or had uncertain significance. VUO9s also contained many fs and nonsense variants. These result support the idea that rare pathogenic variants in TET2 are currently underrecognized as contributory, although they are likely to help drive leukemogenesis. Greater understanding of the importance of individual TET2 variants and additional classification metrics are needed. Disclosures DiNardo:Karyopharm: Honoraria; Abbvie: Honoraria; Agios: Consultancy; Medimmune: Honoraria; Celgene: Honoraria; Bayer: Honoraria. Daver:Karyopharm: Research Funding; Incyte: Consultancy; Novartis: Consultancy; ImmunoGen: Consultancy; Sunesis: Consultancy; Pfizer: Consultancy; Daiichi-Sankyo: Research Funding; Kiromic: Research Funding; Alexion: Consultancy; Otsuka: Consultancy; Sunesis: Research Funding; Incyte: Research Funding; ARIAD: Research Funding; BMS: Research Funding; Karyopharm: Consultancy; Novartis: Research Funding; Pfizer: Research Funding. Kadia:Celgene: Research Funding; Takeda: Consultancy; BMS: Research Funding; Abbvie: Consultancy; Novartis: Consultancy; Novartis: Consultancy; Amgen: Consultancy, Research Funding; Jazz: Consultancy, Research Funding; Abbvie: Consultancy; Pfizer: Consultancy, Research Funding; Takeda: Consultancy; Amgen: Consultancy, Research Funding; BMS: Research Funding; Pfizer: Consultancy, Research Funding; Jazz: Consultancy, Research Funding; Celgene: Research Funding. Konopleva:Stemline Therapeutics: Research Funding; abbvie: Research Funding; cellectis: Research Funding; Immunogen: Research Funding. Andreeff:Amgen: Consultancy, Research Funding; Astra Zeneca: Research Funding; Jazz Pharma: Consultancy; Oncolyze: Equity Ownership; Aptose: Equity Ownership, Membership on an entity9s Board of Directors or advisory committees; Oncoceutics: Equity Ownership, Membership on an entity9s Board of Directors or advisory committees; SentiBio: Equity Ownership; United Therapeutics: Patents & Royalties: GD2 inhibition in breast cancer ; Reata: Equity Ownership; Celgene: Consultancy; Eutropics: Equity Ownership, Membership on an entity9s Board of Directors or advisory committees; Daiichi-Sankyo: Consultancy, Patents & Royalties: MDM2 inhibitor activity patent, Research Funding.

Results of a Phase 1, Dose-Escalation Study of FF-10501-01 in Patients with Relapsed/Refractory Acute Myeloid Leukemia (AML) or Hypomethylating Agent (HMA)-Resistant Myelodysplastic Syndrome (MDS)

IntroductionFF-10501-01 is an orally bioavailable potent inhibitor of inosine-5-monophosphate dehydrogenase (IMPDH). In vitro, FF-10501-01 reduced the proliferation of multiple human-derived myeloid leukemia parent and hypomethylating agent (HMA)-resistant cell lines in a concentration dependent manner. Incubation of cells with FF-01501-01 also reduced intracellular pools of GMP, GDP and GTP, and this effect was reversed by addition of guanosine, demonstrating that the effect was due to inhibition of IMPDH. FF-10501-01 was evaluated in a Phase 1 clinical trial in patients with relapsed/refractory AML and HMA-resistant MDS and results are presented below.MethodsThis was an open-label, single-institution, Phase 1, dose escalation study in patients with refractory AML and MDS, or in patients with AML > 60 years of age not eligible for other treatment. The study was conducted as a “3+3” design. The objectives of the study were to describe the adverse event profile, pharmacokinetics, pharmacodynamics, recommended Phase 2 dose (RP2D) and preliminary efficacy of FF-10501-01. Oral FF-10501-01 was administered in escalating doses ranging from 50 - 500 mg/m2 twice daily (BID) for periods of 14, 21 or 28 days in a 28-day treatment cycle and dose escalation to the next dose cohort was governed by the decision of a safety review committee. The pharmacokinetics of FF-10501-01 and its primary active metabolite were determined by measuring blood levels at various times after administration; pharmacodynamics were based on measurements of xanthine monophosphate (XMP) at various time points. The institutional review board of the participating institution approved the protocol and all protocol amendments, and all patients provided written informed consent.ResultsThirty-seven patients were treated with FF-10501-01. Most (78%) of patients had AML; the median age of all patients was 78 (range: 58 - 88). All patients had received prior therapy (median number 3, range: 1 - 6) and 3 patients had undergone stem-cell transplantation. FF-10501-01 was well tolerated; the most frequently observed treatment-emergent related adverse events were fatigue (22%), diarrhea (11%), nausea (11%) and oral mucositis (8%). Of all adverse events reported, only 3 were Grade 3 in severity (one episode each of neutropenia, thrombocytopenia and oral mucositis); all others were Grade 1 or 2. The RP2D was determine to be 400 mg/m2 given for 21 days every 28 days. In the MDS cohort, 1 of 8 evaluable patients demonstrated a complete bone marrow response that persisted for 19 months and 3 of 24 evaluable patients with AML demonstrated partial responses; in 1 of these patients, the response persisted for 31 months. One additional patient with AML continued treatment with FF-10501-01 for 14 months without evidence of progression. FF-10501-01 displayed dose proportional pharmacokinetics with no evidence of drug accumulation; mean steady-state observed half-lives ranged from 3 - 9 hours. Blood concentrations of XMP were variable between subjects as a function of dose and time. Following a single administration of FF-10501-01, on average, there appeared to be a reduction in XMP from baseline and maximum inhibition of pre-dose blood concentrations of XMP were consistently near or above 50% following the first administration of FF-10501-01.ConclusionFF-10501-01, was well tolerated and demonstrated evidence of efficacy in a heavily pre-treated population of patients with AML and MDS. FF-10501-01 had predictable pharmacokinetics and pharmacodynamic testing verified its mechanism of action as an IMPDH inhibitor. FF-10501-01 in combination with other agents, is currently undergoing additional clinical testing. DisclosuresKurman:Fujifilm Pharmaceuticals USA, Inc.: Consultancy. DiNardo:Abbvie: Honoraria; Bayer: Honoraria; Medimmune: Honoraria; Agios: Consultancy; Karyopharm: Honoraria; Celgene: Honoraria. Pemmaraju:Affymetrix: Research Funding; SagerStrong Foundation: Research Funding; plexxikon: Research Funding; daiichi sankyo: Research Funding; samus: Research Funding; celgene: Consultancy, Honoraria; abbvie: Research Funding; cellectis: Research Funding; stemline: Consultancy, Honoraria, Research Funding; novartis: Research Funding. Ravandi:Macrogenix: Honoraria, Research Funding; Sunesis: Honoraria; Xencor: Research Funding; Orsenix: Honoraria; Seattle Genetics: Research Funding; Sunesis: Honoraria; Astellas Pharmaceuticals: Consultancy, Honoraria; Xencor: Research Funding; Macrogenix: Honoraria, Research Funding; Bristol-Myers Squibb: Research Funding; Abbvie: Research Funding; Abbvie: Research Funding; Jazz: Honoraria; Amgen: Honoraria, Research Funding, Speakers Bureau; Jazz: Honoraria; Amgen: Honoraria, Research Funding, Speakers Bureau; Seattle Genetics: Research Funding; Astellas Pharmaceuticals: Consultancy, Honoraria; Bristol-Myers Squibb: Research Funding; Orsenix: Honoraria. Madden:Fujifilm Pharmaceuticals USA, Inc.: Consultancy. Maier:Fujifilm Pharmaceuticals USA, Inc.: Consultancy. Iwamura:Fujifilm Corporation: Employment.

Mesenchymal stromal cells from myelodysplastic and acute myeloid leukemia patients display in vitro reduced proliferative potential and similar capacity to support leukemia cell survival

BackgroundMesenchymal stromal cells (MSCs) are an essential element of the bone marrow (BM) microenvironment, playing a crucial function in regulating hematopoietic stem cell proliferation and differentiation. Recent findings have outlined a putative role for MSCs in hematological malignancy development. So far, conflicting results have been collected concerning MSC abnormalities in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). In particular, a considerable amount of evidence has been accumulated strongly supporting a permissive role of MSCs in malignancy evolution to MDS, while a potentially causative or promoting function performed by MSCs in AML has not yet been fully clarified. Here, we compared MSCs isolated from healthy, MDS, and AML subjects to investigate MSC alterations and to emphasize putative common and/or diverse features.MethodsWe isolated and expanded MSCs from AML patients (AML-MSCs) and MDS patients (MDS-MSCs), and we analyzed and compared their phenotypic and functional properties with respect to each other and versus healthy donor-derived MSCs (HD-MSCs).ResultsWe found that stable MSC cultures could be easily established from HD and MDS mononuclear BM-derived cells, while a substantial fraction (25%) of AML patients failed to yield MSCs. Nevertheless, isolated MDS-MSCs and AML-MSCs, as well as HD-MSCs, contained the basic features of MSCs. Indeed, they displayed similar surface marker expression and efficient capacity to differentiate versus osteogenic and adipogenic lineage in vitro. We also proved that MDS-MSCs and AML-MSCs, analyzed by fluorescence in-situ hybridization, did not harbor leukemic cell cytogenetic abnormalities. Moreover, MDS-MSCs and AML-MSCs were similar in terms of ability to sustain AML cell viability and immune-regulatory capacity. However, we were also able to detect some differences between AML-MSCs and MDS-MSCs. Indeed, we found that the frequency of rescued MSCs was lower in the AML group than in the HD and MDS groups, suggesting that a reduced number of MSC precursors could inhabit AML BM. Instead, MDS-MSCs showed the lowest proliferative capacity, reflecting some intrinsic and particular defect.ConclusionsOverall, our results elucidated that MDS-MSCs and AML-MSCs did not show macroscopic and/or tumor-related defects, but both displayed functional features potentially contributing to favor a leukemia-protective milieu.

Chronic Myeloid Leukemia Following Treatment for Primary Neoplasms or Other Medical Conditions.

Therapy-related chronic myeloid leukemia (CML) has been reported, but its clinical presentation and pathologic features have not yet been well characterized. Twenty-one cases of CML following treatment for primary diseases were collected and retrospectively analyzed. The clinical presentation, pathologic features, and cytogenetic profile were similar to de novo CML. In particular, those with an isolated Philadelphia chromosome constituted 88.9% of our cases, and additional aberrations characteristic of therapy-related acute myeloid leukemia/myelodysplastic syndrome (AML/MDS) were not identified in this study. The patients responded to imatinib/derivatives and survived with limited follow-up. Therapy-related CML has a clinical presentation, pathologic features, and cytogenetic profile akin to de novo CML. Absence of additional significant aberrations seems to suggest a pathogenesis different from therapy-related AML/MDS. Therapy-related CML exhibits a robust therapeutic response to imatinib/derivatives and favorable clinical outcomes similar to de novo CML.

Abstract LB-215: Analysis of mutations associated with response to glasdegib in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS)

Abstract Background: The Hedgehog (Hh) signaling pathway is key to development, differentiation, and stem cell maintenance. In cancer, dysregulation of Hh signaling is associated with solid tumors and hematological malignancies. Hh signaling in AML and MDS is thought to promote the renewal and maintenance of leukemic stem cells, which may lead to chemotherapy resistance and recurrence. Glasdegib is a potent and selective oral inhibitor of Smoothened, a transmembrane protein that stimulates Hh signaling. Here we report the results of an exploratory analysis to profile mutations in 118 bone marrow samples and 77 peripheral blood samples of patients with previously untreated AML or high-risk MDS treated with chemotherapy with or without glasdegib in phase I/II clinical trials. Materials and Methods: We used targeted resequencing to survey 109 genes, and a polymerase chain reaction assay to detect FLT3 internal tandem duplications. Resequencing and response data were obtained from two arms, 1) an intensive group (n=61) treated with a combination of cytarabine/daunorubicin plus glasdegib, and 2) a non-intensive group (n=73) treated with low-dose cytarabine (LDAC) plus glasdegib (n=44) or LDAC alone (n=19). We assessed significantly mutated genes by Fisher's Exact Test at p ≤ 0.05. Results: In the combined dataset we found that mutations in NF1 (P=0.006), KRAS (P=0.028), or a combination of KRAS, NRAS, and NF1 (P=0.013) were associated with a negative response. Mutations in NPM1 (P=0.006), MPL (P=0.041), RB1 (P=0.041), or SF3B1 (P=0.041) were associated with a positive response. When split by arm, in the intensive group mutations in TP53 (P=0.001), NF1 (P=0.035), or CREBBP (P=0.041) were associated with negative response, whereas mutation in NPM1 was associated with positive response (P=0.046). In the non-intensive group, mutations in RSPH10B2 (P=0.036) or a combination of KRAS, NRAS, and NF1 (P=0.031) were associated with negative response, whereas mutation in CREBBP (P=0.007) was associated with positive response. We discuss the implications of these mutations in the context of Smoothened inhibition and the leukemic stem cell hypothesis. Conclusions: Mutational profiling of patients with AML or high-risk MDS treated with glasdegib highlights alterations in genes associated with response and the potential role of Hh signaling in these malignancies. Citation Format: Keith A. Ching, Donghui Huang, Kai Wang, Mark Ozeck, Paul Lira, Jingjin Gao, Jadwiga Bienkowska, Paul Rejto, James Hardwick, Thomas O'Brien, Geoffrey Chan. Analysis of mutations associated with response to glasdegib in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-215.

Familial aggregation myelodysplastic syndromes/acute myeloid leukemia: report of one pedigree and review of literature

Objective To investigate the diagnosis, clinical characteristics, gene mutation and treatment of familial aggregation myelodysplastic syndromes/acute myeloid leukemia(MDS/AML). Methods Bone marrow morphocytology, immunophenotype, cytogenetics, gene mutation, therapeutic effects and prognosis of the brothers in the line of MDS/AML patients were analyzed, and the related literature was reviewed. Results The prover developed AML after the diagnosis of MDS-refractory anemia with excess blasts-Ⅰ (MDS-RAEB Ⅰ) for 4 months. With elder brother developed MDS RAEB-Ⅱ after the diagnosis of MDS-refractory cytopenia with multilineage dysplasia for 3 months. The survival period was 5 and 8 months. Conclusion Familial aggregation MDS/AML is rare with poor prognosis, and its diagnosis needs to be combined with family history, cytogenetics and molecular biology. Key words: Myelodysplastic syndromes; Leukemia, myeloid, acute; Germline mutation