Relapsed Acute Myelogenous Leukemia Research Articles

Platelet Factor 4 Binds to Low-Density Lipoprotein Receptor to Block Leukemic Stem Cell Expansion and Recurrence

Healthy hematopoietic stem cells (HSCs) reside in highly specialized microenvironments within the bone marrow, commonly referred to as niches. HSC activity is tightly regulated by various cellular and molecular niche constituents that ensure healthy hematopoiesis. However, through the accumulation of mutations, hematopoietic stem and progenitor cells can give rise to leukemia-initiating cells or leukemic stem cells (LSCs), which play a vital role in the onset, progression, and treatment outcome of acute myelogenous leukemia (AML). In AML, the expansion of the leukemic clone is associated with impaired healthy hematopoiesis, resulting in severe anemia, thrombocytopenia, and immunodeficiency, which can lead to severe morbidity. Current therapeutic options mainly eliminate the bulk of leukemic cells but do not efficiently target LSCs, leading to the high rates of relapse seen in AML patients. Recent studies suggest that LSCs hijack and alter the healthy bone marrow niche to better support their maintenance and proliferation. Understanding how LSCs interact with the bone marrow microenvironment is crucial for eradicating LSCs and preventing AML relapse. Our previous work showed that platelet factor 4 (PF4), a chemokine stored in platelet alpha-granules and secreted by bone marrow megakaryocytes, can induce quiescence in healthy myeloid-biased HSCs ( Nature Medicine 2014; Developmental Cell 2018). Here, we investigate the regulation of malignant LSCs by PF4 using mouse and human AML models. In an aggressive mouse AML model, MLL-AF9, our results show that recombinant PF4 blocks the proliferation of phenotypic LSCs (Lineage − IL7Rα − Sca1 − MLL-AF9-GFP + c-Kit high CD34 + FcγRII/III high) in vitro (70% reduction; P=0.0279). Strikingly, cell cycle analyses revealed that in vivo, both LSCs and bulk AML proliferation are significantly inhibited 24 hours post-PF4 (80 mg/kg) injection, resulting in a significantly lower leukemic burden. By contrast, Pf4 -/- mice exhibited rapid AML disease progression via increased LSC proliferation. Furthermore, using a genetic mouse model ( Pf4-Cre; iDTR) where PF4-secreting megakaryocyte cells can be depleted in vivo in leukemic mice, our results revealed that megakaryocyte depletion led to poor AML survival due to accelerated disease progression (Log-rank P<0.0017). These results demonstrate that megakaryocyte-derived PF4 can directly regulate the proliferation of leukemia cells. Interestingly, our results indicate that AML drives striking alterations in bone marrow megakaryocytes, including a lower frequency, reduced cell maturation, and reduced secretion of PF4 (~80% reduction, P<0.0001) compared to healthy controls. Accordingly, PF4 levels are reduced in the serum of myelodysplastic syndrome patients where hyperproliferative malignant cells are found alongside dysplastic megakaryocytes. To assess whether recombinant PF4 can alter the course of AML relapse in a preclinical experimental setting, we treated moribund leukemic mice with the chemotherapeutic drug Cytarabine followed by 3 daily I.V. injections of PF4 (80 mg/kg) or saline. Strikingly, this short treatment with PF4 preferentially reduced the frequency of LSCs in vivo during the relapse phase of AML (75% reduction; P=0.05). Furthermore, mice transplanted with MLL-AF9 AML cells that were pre-treated with Cytarabine and PF4 in vitro had prolonged overall survival (Log-rank P<0.0132) compared to Cytarabine alone. Importantly, two of six mice had no detectable AML up to 150 days post-transplantation. Finally, single-cell RNA sequencing experiments revealed that PF4 signals through Low-Density Lipoprotein Receptor (LDLR) on LSCs, whose expression is significantly upregulated upon Cytarabine treatment, during the relapse phase. Functional studies with fluorescently labeled low-density lipoprotein (LDL) confirmed that PF4 limits LSC uptake of LDL via LDLR to block LSC proliferation ( P=0.0044), suggesting an important role for PF4 in AML metabolism. Altogether, our studies reveal an unknown function for PF4 in AML and highlight PF4's potential as an effective adjuvant therapy in preventing AML relapse by inhibiting the recurrence of chemotherapeutic-resistant LSCs.

Trends in Allogeneic Stem Cell Transplantation for Good Risk Acute Myelogenous Leukemia in First Complete Remission: A Longitudinal Study of > 15 Years from the ALWP/EBMT

Background: Favorable acute myelogenous leukemia (AML) includes AML with t (8:21), inv (16), and those with NPM1 without FLT3- ITD without adverse cytogenetics (ELN 2022). The incidence of relapse (RI) in favorable-risk AML with chemotherapy is 35%-40%. Although RI is ~20% lower with allogeneic transplantation (HSCT), transplantation is usually not indicated in favorable risk AML at first complete remission (CR1) due to transplant-related mortality. However, in recent years, HSCTs have been associated with significantly lower non relapse mortality (NRM) and better outcomes. Methods:Our aim was to assess outcomes of HSCT in favorable risk AML (t (8:21), inv (16), and NPM1 mutFLT3 WT) in CR1, comparing 3 time periods: 2005-2009, 2010-2014, and 2015-2021. Statistical tests included a multivariate analysis (MVA) adjusting for potential confounding factors performed using a Cox proportional-hazards regression model for main outcomes. Results: 1850 patients (pts) were included, 526 with t (8:21), 625 with inv (16), and 699 with NPM1 mutFLT3 WT (normal karyotype). 222 pts were transplanted in 2005-2009, 392 in 2010-2014, and 1236 in 2015-2021. As the follow-up period differed, being 103.1 (IQR, 92.1-114.0), 78.3 (IQR, 69.4-86.3), and 32.0 (IQR, 29.5-34.5) months, respectively (p<0.0001), all survival events were censored at 3 y. Pts undergoing HSCT in 2015-2021 were older, with a median age of 50.9 (range 18.2-76.4) vs40.4 (range 18.3-67.7) and 42.4 (range 18.4-71) y, in those transplanted in 2005-2009 and 2010-2014, respectively (p<0.0001). More pts >50 y of age were transplanted in the latest period with 52.7% vs the 2 earlier periods 27.9% and 32.1% (p<0.0001) and figures for >60 y were 25.4% vs 8.1% and 11% (p<0.0001), respectively. In 2005-2009 the most frequent diagnosis was t (8:21) at 44.6%, while in 2015-2021, it was NPM1 mutFLT3 WT at 45.6% (p<0001). In 2005-2009, the most frequent donors were matched siblings (MSD) (63.1%), while in 2015-2021 they were unrelated (UD) (50.7%). Haploidentical (haplo) transplants increased from 5.9% to 14.5% (p<0.0001). Bone marrow grafts decreased from 24.8% to 13.2%, while peripheral blood (PB) grafts increased from 75.2% to 86.8% (p<0.0001). Conditioning was myeloablative in 69.8%, 64.8%, and 60.2% and was reduced intensity in 30.2%, 35.2%, and 39.8% in pts transplanted in 2005-2009, 2010-2014, and 2015-2021 (p=0.014). Graft-versus-host disease (GVHD) prophylaxis with in vivo T cell depletion or post-transplant cyclophosphamide (PTCy) was more frequent in 2015-2021 compared to the other two periods (p<0.0001). Day 60 engraftment (ANC >0.5 x 10 9/L) was 98.2 % vs 98.4% vs 98.5% (p=0.17). Day 180 incidence of acute (a) GVHD grade II-IV was 18.2%, 21.1%, and 21.6%; grade III-IV was 5.1% 5.7%, and 7.3% while the incidence of 3-y chronic (c) GVHD was 49.3%, 50.4% and 39.2%. On MVA the incidence of total cGVHD was reduced in HSCTs performed >2015 compared to those performed in 2005-2009, hazard ratio (HR) =0.74 (95% CI 0.56-0.99, p=0.046) and GVHD-free, relapse-free survival (GRFS) improved for pts transplanted from 2010-2014 vs those transplanted in 2005-2009, HR=0.74 (95% CI 0.56-0.98, p=0.037) (Figure 1). All other HSCT outcome parameters including NRM, RI, leukemia-free survival (LFS), and overall survival (OS) did not differ (Figure 1) with no improvement >2015 compared to 2010-2014 (Figure-1 A). LFS, OS, and GRFS were superior in pts with t (8:21) with HR=1.32 (95% CI 1.03-1.68, p=0.026), HR=1.38 (95% CI 1.04-1.83, p=0.027) and HR=01.25 (95% CI 1.02-1.53, p=0.035), respectively. Other poor prognostic factors were older pt age (by 10 y) for NRM and OS; 10/10 and 9/10 UD vs MSD for aGVHD II-IV (9/10 also for III-IV aGVHD) and haplo vs MSD for NRM, OS, aGVHD II-IV, and total cGVHD. The combination of female donor to male pt was a poor prognostic factor for NRM, OS, GRFS, and cGVHD. In vivo T cell depletion was a positive prognostic factor for GRFS and reduced incidence of aGVHD and cGVHD. PTCy was associated with a lower incidence of cGVHD and PB grafts with an increased risk of total cGVHD. Conclusions: In this retrospective analysis of HSCT in pts with favorable risk AML in CR1, transplanted over 16 years, we observed an increased number of transplants in pts >60y, from UD and haplo with PB grafts and in vivo T cell depletion or PTCy as GVHD prophylaxis. Most importantly, 3-y GRFS improved >2010 and total cGVHD reduced >2015, while other HSCT outcome parameters have not changed.

Mitotic recombinatory evolution in acute leukemia

A cohort of leukemia cases is presented with ancillary testing that includes microarray studies, karyotyping, FISH, and RNA sequencing to illustrate clonal evolution. Common evolution etiology with each case is apparent homologous mitotic recombination (HMR). The cohort includes: four cases of Pre B-cell acute lymphoblastic leukemia (B-ALL) with a single translocation derivative (19)t(1;19)(q23.3;p13.3), an acute myelogenous leukemia (AML) case with a paracentric inversion of 11q13.3q23 in both homologues confirmed as a rare KMT2A-MAML2 gene fusion, and a transplant patient in AML relapse with a t(6;11)(6q27;q23) and evolution to an additional derivative 6 chromosome. The PBX1-TCF3 fusion in the t(1;19) B-ALL subgroup has long been associated with clones that show either the balanced translocation (∼25%) or the unbalanced single derivative 19 (∼75%). Evidence from the CMAs and FISH is consistent with HMR initiating at either the PBX1 translocation breakpoint or at a more proximal long arm site that mediates the evolution to the unbalanced form. This is contrary to the previous assumptions of either nondisjunction duplication of the normal homologue with loss of the translocation derivative 1 or an original trisomy 1 that loses the translocation derivative 1. Relapse from an unrelated transplant donor created unique allele dosage ratios in the microarray of the AML patient with the t(6;11) KMT2A-AFDN fusion. An HMR-based evolution initiation site proximal to the 6q27 AFDN fusion gene is evident in the microarray of chromosome 6, the known oncogenic fusion derivative. The HMR selection driver in both AML cases is very likely associated with the DNA doubling of the oncogenic fusions in 6q and 11q, respectively. Since the oncogenic derivatives in the 1;19 cases are clearly the retained derivative 19, selection for the HMR clonal evolution in 1q is apparently based on the known proliferative advantage of extra copies of 1q in B-ALL and other malignancies. Although selection-based HMR can effectively initiate at any site proximal to a driver gene fusion, it appears that the translocation breaksite is common for many translocations. In addition, evidence from HMR evolution related distal 11q mutations, numerous unbalanced CCND1/IGH translocations, and the double MAML2/KMT2A presented in this study suggest that a recombinatorial "hot spot" exists near the CCND1 gene in many rearrangements or mutations within 11q.

Dexamethasone during Leukemia Induction Therapy to Reduce Incidence of Acute Myelogenous Leukemia Relapse

Background: Dexamethasone is an anti-inflammatory steroid used with chemotherapy to prevent nausea/vomiting. Dexamethasone reduces chemo-resistance through inhibition of cytokine production and proliferation via nuclear factor kappa B (NF-kB) dependency. NF-kB is a pro-inflammatory transcription factor. When inactivated, NF-kB complexes are sequestered by inhibitors of kappa-B (I-kB) in the cytoplasm. Upon activation, NF-kB dimers translocate to the nucleus, activating kB responsive DNA. In AML, it has been found that NF-kB is highly activated, suggesting it is an integral part of AML biology. Approximately, 40% of patients diagnosed with AML have demonstrated increased activity of NF-kB and enhanced chemoresistance. In this study, we investigate the effect of dexamethasone given as adjuvant antiemetic prophylaxis on clinical AML outcome. Methods: A single-center, retrospective, descriptive study, from May 2015 to September 2021, was conducted in AML adult cohort admitted for induction therapy at Baylor St. Luke's Medical Center. Dexamethasone exposure was defined as a dose at least 8 mg daily for a total of 5-7 days during induction therapy and consolidation. Primary endpoint was clinical efficacy including event free survival (EFS) and overall survival (OS). Secondary endpoints were complete remission (CR) in patients receiving dexamethasone vs. not. Statistical analysis using SAS software included descriptive and inferential statistics. Results: 106 patients were evaluated. 47 (44.3%) were exposed to dexamethasone. Median age was 61 years (21-88) vs 55 years (26-82), p=0.03. ELN-2017 distribution among dexamethasone exposed vs. those who were not was in favorable 32% vs 15%, intermediate 32% vs 26 % and unfavorable 37% vs 58%. EFS was 745 days (d) vs. 164 d, in patients receiving dexamethasone vs. not, p=0.0001, HR=0.31, CI=0.16-0.54 (Fig 1). Subgroup analysis by ELN-2017 classification demonstrated that superior EFS was driven by intermediate risk, p=0.0004, HR=01, CI= 0.03-0.3 (Fig 2). In de novo AML, EFS was not reached (NR) vs 162d in AML patients dexamethasone exposed vs. not exposed (p=0.0001, HR=0.12, CI=0.05-0.29). Similarly, for secondary AML, EFS was 1,322 d vs 199 d, in dexamethasone exposed vs not exposed, p=0.05, HR=0.37, CI=0.14-0.92. CR/CRi was 60 % vs 40.2% for patients dexamethasone vs. not, p=0.2. With EFS, as outcome of interest, cox regression model was constructed accounting for age, ELN-2017 classification, and dexamethasone exposure demonstrating that favorable ELN-2017 (p=0.004; HR=0.17; CI=0.05-0.58) and exposure to dexamethasone (p=0.001; HR=3.7, CI=1.6-8.2) interacted to induce superior EFS. Conclusions: Dexamethasone exposure is associated with significant lower relapse risk in adult diagnosed with AML receiving induction. Our study is "proof of concept” for dexamethasone activity against AML. Albeit activity seems restricted to intermediate ENL-2017 subgroup, mitigation of relapse risk seems wide among de novo and secondary AML. Clinical studies are needed to reconfirm our findings and to uncover the inflammatory pathways targeted by dexamethasone leading to anti-leukemia effect. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Relationship Between Pretransplantation Nutritional Status and Outcome in Adults with Acute Myelogenous Leukemia Undergoing Allogeneic Hematopoietic Cell Transplantation

Pretransplantation nutritional status may impact outcome after allogeneic hematopoietic cell transplantation (HCT). Various simple screening tools have been developed and used to identify patients at risk of malnutrition; however, how best to use these screening tools is unclear, and their accuracy for the prediction of adverse outcomes is unknown. To investigate how these different measures contribute to outcome prediction, we examined a large cohort of adults with acute myelogenous leukemia (AML) who underwent allogeneic HCT in first or second remission at our institution between April 2006 and May 2021. We assessed the prognostic role of the Nutrition Risk Index (NRI), which combines weight loss and serum albumin, in 970 adults with AML in first or second remission who had usual body weight information available at AML diagnosis or relapse and before HCT. A low NRI at the time of conditioning for HCT was associated with higher nonrelapse mortality (hazard ratio [HR], .97; 95% confidence interval [CI], .95 to .98; P < .001) and relapse risk (HR, .98; 95% CI, .96 to .99; P < .001) and decreased relapse-free survival (HR, .97; 95% CI, .96 to .98; P < .001) and overall survival (HR, .97; 95% CI, .96 to .98; P < .001), as was a low pre-HCT serum albumin level. After multivariable adjustment, NRI, but not weight loss alone, was associated with outcome. The predictive ability of NRI was overall relatively low and comparable to that of serum albumin, with a C-statistic not exceeding .59. Taken together, our data indicate that pre-HCT level of serum albumin, an acute-phase protein recognized to more accurately reflect the severity of the inflammatory response compared with poor nutritional status, but not weight loss, is independently associated with post-HCT outcome in patients with AML. © 2022 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

A CASE OF CARDIAC MYELOID SARCOMA POST-ALLOGENEIC TRANSPLANTATION

TYPE: Late Breaking Abstract TOPIC: Cardiovascular Disease INTRODUCTION: Extramedullary relapse of acute myelogenous leukemia (AML) has been reported in a small percentage of patients who received hematopoietic stem cell transplantation. Among the sites of involvement, cardiac myeloid sarcoma or cardiac chloroma is an exceedingly rare presentation. We present a case of a right atrial chloroma without medullary involvement in a patient with AML in remission. CASE PRESENTATION: A 53-year-old woman with a background of AML with myelodysplasia-related features status post-induction chemotherapy followed by an allogeneic hematopoietic stem cell transplant came to the emergency department with chest pain and shortness of breath. The patient was noted to have pericarditis and treatment was initiated. Transthoracic echocardiogram showed a right atrial mass extending into the pericardium, which was confirmed by cardiac magnetic resonance imaging (MRI). Initial right heart catheterization with tissue biopsy was indeterminate and a second one showed atypical cells with immunohistochemical stains consistent with myeloid sarcoma. Bone marrow biopsy did not show evidence of AML and treatment with Azacitidine and Venetoclax was indicated. DISCUSSION: The five-year survival rate for AML is 29.5% and the majority of patients die from infection or hemorrhage. The presence of cardio-respiratory symptoms in our patient led to an early diagnosis of cardiac myeloid sarcoma. It is a rare presentation that is usually diagnosed at autopsy with an incidence <1%. CONCLUSIONS: A high index of suspicion is a cornerstone in the early diagnosis and timely management of cardiac myeloid sarcoma. DISCLOSURE: No significant relationships. KEYWORD: chloroma

Phase 1/2, Open-Label, Dose Escalation, Dose Expansion Study of Menin Inhibitor DSP-5336 in Adult Patients (pts) with Acute Leukemia with and without Mixed-Lineage Leukemia (MLL)-Rearrangement or Nucleophosmin 1 (NPM1) Mutation

Relapsed or refractory acute leukemia (AL) in adults, including acute myelogenous leukemia (AML) and acute lymphocytic leukemia (ALL), still represents a significant unmet need. Once AML or ALL relapses after initial treatment, the prognosis is extremely limited, with median survival <6 mo for AML and <1 y for ALL. This is especially true of AML or ALL with MLL rearrangements (MLLr) or relapsed AML with NPM1 mutations. Translocations of the MLL gene, found in approximately 5% to 10% of adult patients with AL, result in an aggressive subtype of leukemia, with a median overall survival (OS) of approximately 9 months and a very high rate of relapse after standard induction therapy for AML or ALL. The NPM1 mutation (NPM1m) is seen in approximately 30-35% of adult AML cases, most commonly in de novo AML, and is associated with a more favorable prognosis in newly diagnosed AML. However, this favorable prognostic effect is lost in the presence of concomitant FLT3-internal tandem duplication (ITD) mutations, which are seen in 40% to 50% of AML with mutated NPM1.These genomic alterations have been the focus for the development of DSP-5336, a novel small-molecule oral therapy that prevents binding of the menin protein to MLL fusion proteins that drive leukemogenesis.In nonclinical studies, DSP-5336 showed selective cell growth inhibitory activity against humanAL cell lines with MLLr or NPM1m. In addition, evidence of antitumor activity and survival advantage was demonstrated in 3 AML xenograft models with MLLr and/or NPM1m. Treatment with DSP-5336 may result in the reduction of leukemic cells, offering therapeutic benefits that include achieving complete remission and prolonged survival in patients with relapsed or refractory AML with MLLr or NPM1m or pts with relapsed or refractory ALL with MLLr.An open-label, single-arm, phase 1/2 study (NCT04988555) of DSP-5336 is being started to evaluate the safety and efficacy of DSP-5336 and determine the recommended phase 2 dose (RP2D) in adults aged ≥18 y with relapsed/refractory AML or ALL after at least one line of standard therapy, including hematopoietic stem cell transplant. Key inclusion criteria are ECOG performance status 0-2 and adequate cardiac, renal, and hepatic function. Patients on the strong CYP3A4 inhibitors ketoconazole, itraconazole, or isavuconazole, are excluded unless they can be safely taken off these medications or switched to another antifungal medication at least 7 days prior to start of study treatment.Patients will be dosed twice daily for 28 days per cycle. The study design is depicted below in Figure 1. In phase 1, 21-30 pts will be enrolled into multiple ascending dose cohorts (1-6 pts per dose level), with dose escalation determined using a two-parameter Bayesian logistic regression model. Determination of the RP2D will be informed by the maximum biologic effect or maximum tolerated dose, whichever is lower. The phase 2 study will include arm A (relapsed or refractory AML with MLLr) and arm B (relapsed or refractory AML with NPM1m) (Figure 1). Patients will be treated at the RP2D to evaluate clinical activity and safety, which will be monitored using Bayesian posterior probability to optimize enrollment with Bayesian stopping rules. Bayesian monitoring of responses will be started after the first 10 enrolled patients are evaluable for efficacy. Study endpoints are summarized in Table 1. [Display omitted] DisclosuresDaver: Genentech: Consultancy, Research Funding; Gilead Sciences, Inc.: Consultancy, Research Funding; Sevier: Consultancy, Research Funding; Hanmi: Research Funding; Trillium: Consultancy, Research Funding; Trovagene: Consultancy, Research Funding; Novartis: Consultancy; ImmunoGen: Consultancy, Research Funding; FATE Therapeutics: Research Funding; Glycomimetics: Research Funding; Abbvie: Consultancy, Research Funding; Astellas: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Bristol Myers Squibb: Consultancy, Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; Novimmune: Research Funding; Jazz Pharmaceuticals: Consultancy, Other: Data Monitoring Committee member; Dava Oncology (Arog): Consultancy; Celgene: Consultancy; Syndax: Consultancy; Shattuck Labs: Consultancy; Agios: Consultancy; Kite Pharmaceuticals: Consultancy; SOBI: Consultancy; STAR Therapeutics: Consultancy; Karyopharm: Research Funding; Newave: Research Funding. Affinito: Sumitomo Dainippon Pharma Oncology, Inc: Current Employment. Cai: Sumitomo Dainippon Pharma Oncology, Inc: Current Employment. Dobrowolska: Sumitomo Dainippon Pharma Oncology, Inc: Current Employment. Dow: Sumitomo Dainippon Pharma Oncology, Inc: Current Employment. Eguchi: Sumitomo Dainippon Pharma: Current Employment. Song: Sumitomo Dainippon Pharma Oncology, Inc: Current Employment. Stoudemire: Sumitomo Dainippon Pharma Oncology, Inc: Current Employment. Watanbe: Sumitomo Dainippon Pharma Oncology, Inc: Current Employment. Komarnitsky: Sumitomo Dainippon Pharma Oncology, Inc: Current Employment.

PCN51 Annual Healthcare Resource Utilization and Costs in U.S. Patients Diagnosed with Relapsed Acute Myeloid Leukemia

This study examined annual healthcare utilization and associated healthcare costs incurred in patients diagnosed with relapse AML. A retrospective analysis was conducted in the Premier Healthcare Database. Using ICD-10-CM codes for AML in relapse, the study identified adult patients during the period of 1/1/2016 to 9/30/2018 and were followed from index to inpatient death, one year in relapse, or end of study period (9/30/19). Outcomes of interest included demographic data, comorbidities, outpatient treatment days, inpatient and ICU admissions, and associated costs. A total of 2,290 patients were identified, mean age=61.2 and 46.9% were female. Patient follow-up varied from <90 days (49.4%), at least 180 days (32.8%), to ≥360 days (16.8%). During the one-year follow-up, outpatient hospital utilization averaged 14.6 days. For inpatient hospitalizations, mean admissions per patient were 2.4 (mean LOS=13.4 days). Among hospitalizations, 554 (30.8%) included an ICU admission (LOS=4.2). Regarding costs, mean cost per day for outpatient treatment was $1,793 for an annual cost of $17,968. The mean cost of an inpatient stay was $34,209 and mean cost of an ICU admission during a hospital stay was $23,425. Total annual inpatient treatment cost averaged $77,983. Hospital treatment the year following relapse totaled $169 million, $139 million (82%) attributable to the inpatient setting. Acute myelogenous leukemia (AML), a malignant cancer of bone marrow, affects 4.3 per 100,000 individuals in the US, with a median age of 68 at diagnosis. Treatment options include intensive chemotherapy followed by post-remission therapies including stem cell transplant, less intensive chemotherapy, or supportive care. Median survival is 8-10 months. Prognosis after AML relapse is typically poor as seen in this study, and patients are commonly admitted to the hospital and ICU for treatment. This utilization comes with substantial costs, suggesting the need for therapies that may improve outcomes in AML.

Prospective KIR genotype evaluation of hematopoietic cell donors is feasible with potential to benefit patients with AML

Donor KIR and recipient HLA combinations that minimize inhibition and favor activation of the NK repertoire are associated with improved outcomes after allogeneic hematopoietic cell transplantation (HCT) in patients with myeloid neoplasia. We prospectively evaluated a weighted donor ranking algorithm designed to prioritize HLA-compatible unrelated donors (URDs) with weak inhibitory KIR3DL1/HLA-Bw4 interaction, followed by donors with nontolerized activating KIR2DS1, and finally those with KIR centromeric B haplotype. During donor evaluation, we performed KIR genotyping and ranked 2079 URDs for 527 subjects with myelodysplastic syndrome (MDS) or acute myelogenous leukemia (AML). Among all patients, 394 (75%) had at least 1 KIR-advantageous donor, and 263 (50%) underwent HCT. In patients with AML, KIR3DL1 weak inhibition provided protection from relapse. Compared with KIR3DL1-Weak Inhibiting donors, KIR3DL1-Noninteracting donors were associated with increased risk of relapse (HR, 2.97; 95% CI, 1.33-6.64; P = .008) and inferior event-free survival (EFS; HR, 2.14; 95% CI, 1.16-3.95; P = .015). KIR3DL1-Strong Inhibiting donors were associated with HR, 1.65 (95% CI, 0.66-4.08; P = .25) for AML relapse and HR, 1.6 (95% CI, 0.81-3.17; P = .1) for EFS when compared with the use of KIR3DL1-weak inhibiting donors. Donor KIR2DS1/HLA-C1 status and centromeric KIR haplotype-B content were not associated with decreased risk of AML relapse. There was no benefit to KIR-based donor selection in patients with MDS. This study demonstrates that donor KIR typing is feasible, and prioritization of donors with certain KIR3DL1 genotypes may confer a protection from relapse after HCT in patients with AML.

A Case Report of Unusual Appearance of Multifocal Nodular Fatty Liver Infiltration with Hemosiderosis in A Patient with Leukemia, the Challenge in Diagnosis

Hepatic steatosis is a frequent finding in computed tomography (CT) and magnetic resonance imaging (MRI). Chemotherapy is a predisposing factor for both fatty liver infiltration and hemosiderosis. Unusual appearance and behavior of multiple focal nodular fatty infiltration is rare to encounter and when associated with history of malignancy and/or infection presents a dilemma that a confident diagnosis might not be rendered by MRI thus a diagnostic biopsy would be needed to resolve the uncertainty in diagnosis. We present a patient with second relapse of acute myelogenous leukemia (AML) who developed fungal pulmonary infection while receiving salvage chemotherapy. Progressive target-shaped focal liver lesions which demonstrated characteristic fatty signal intensity on MRI were seen along with features of hemosiderosis of the liver parenchyma. Target and non-target liver tru-cut biopsies had to be performed to reach the final diagnosis of focal fatty infiltration and to rule out the differential diagnosis of liver abscesses and leukemia infiltration.

Early Adaptive Natural Killer Cell Expansion Is Associated with Decreased Relapse After Autologous Transplantation for Multiple Myeloma

Adaptive natural killer (NK) cells are long-lived and exhibit properties of immunologic memory against cytomegalovirus (CMV). We previously reported that expansion of adaptive NK cells after CMV reactivation in recipients of allogeneic hematopoietic cell transplantation (HCT) was associated with a lower rate of relapse of acute myelogenous leukemia. In the present study, we examined the impact of adaptive NK cell expansion in a cohort of 110 individuals who underwent autologous HCT (AHCT) for a lymphoid malignancy (lymphoma or multiple myeloma [MM]). In this cohort, higher absolute numbers of adaptive NK cells (>1.58/μL) at day 28 post-AHCT were associated with significantly decreased risk of relapse in patients with MM. No significant association was seen in patients with lymphoma. Further stratification of MM patients by CMV serostatus found a strong protective effect of adaptive NK cells only in CMV-seropositive individuals. These findings suggest that strategies to increase adaptive NK cells after AHCT may be a therapeutic option in patients with MM.

Isolated retro-orbital granulocytic sarcoma relapse of Acute Myeloid Leukemia after allogeneic hematopoietic stem cell transplantation: a case report.

Granulocytic sarcoma (GS) is rare as an isolated presentation of relapse after allogeneic hematopoietic stem-cell transplantation (allo-HSCT), particularly in adult patients with acute myelogenous leukemia (AML). We report here the case of a 37-year-old man who developed a GS of the retro-orbital as an isolated manifestation of AML relapse 27 months after allo-HSCT. A 37-year-old man was diagnosed with AML and subsequently received allo-HSCT after clinical chemical remission. The patient suddenly presented with painless exophthalmos of the left eye twenty-seven months after allo-HSCT. Orbital magnetic resonance imaging (MRI) revealed left retro-orbital masses. Histopathology revealed diffused infiltration of leukemic blasts. Further systemic investigation showed no leukemic involvement of his other organs. Isolated retro-orbital relapse of AML was diagnosed. Despite treatment using retro-orbital irradiation, the patient died 6 months after presentation. Our patient had a poor survival prognosis, even with timely diagnosis and proper treatment. Although the ophthalmologist has a secondary role in the diagnosis and treatment of leukemia, a prompt recognition of the ocular manifestations and their significance as a sign of possible extramedullary lesion is crucial.

HLA-A alleles influencing NK cell function impact AML relapse following allogeneic hematopoietic cell transplantation

AbstractHLA-B allotypes exhibiting the Bw4 epitope trigger variable inhibitory signaling of KIR3DL1 receptor types, where strong inhibitory HLA-B and KIR3DL1 allele combinations are associated with increased risk for relapse of acute myelogenous leukemia (AML) following allogeneic hematopoietic cell transplantation (HCT). Several HLA-A allotypes also exhibit the Bw4 epitope. Studies with natural killer (NK) cell clones have demonstrated NK inhibition via KIR3DL1 by HLA-A Bw4+ allotypes, but did not delineate strengths of inhibition or hierarchies of NK education. Using primary NK cells from healthy donors, we demonstrate that HLA-A*23, HLA-A*24, and HLA-A*32 proteins are expressed at different densities and exhibit different capacities to educate and inhibit KIR3DL1-expressing NK cells in vitro. Among the HLA-A Bw4+ allotypes, HLA-A*24 and HLA-A*32 demonstrate the strongest inhibitory capacity. To determine if HLA-A allotypes with strong inhibitory capacity have similar negative impact in allogeneic HCT as HLA-B Bw4+ allotypes, we performed a retrospective analysis of 1729 patients with AML who received an allogeneic HCT from a 9/10 or 10/10 HLA allele-matched unrelated donor. Examination of the donor-recipient pairs whose Bw4 epitope was exclusively contributed from HLA-A*24 and A*32 allotypes revealed that patients with HLA-A*24 who received an allograft from a KIR3DL1+ donor experienced a higher risk of disease relapse (hazard ratio, 1.65; 95% confidence interval, 1.17-2.32; P = .004) when compared with patients without a Bw4 epitope. These findings indicate that despite weak affinity interactions with KIR3DL1, common HLA-A allotypes with the Bw4 epitope can interact with KIR3DL1+ donor NK cells with clinically meaningful impact and provide additional insight to donor NK alloreactivity in HLA-matched HCT.

Paired Analyses of AML at Diagnosis and Relapse By Single-Cell RNA Sequencing Identifies Two Distinct Relapse Patterns

Introduction: Despite achievement of complete remission (CR) following chemotherapy, Acute Myelogenous Leukemia (AML) relapses in the majority of adult patients. While relapsed AML is almost always clonally related to the disease at diagnosis, the actual molecular and cellular contributors to chemotherapy resistance and to AML relapse remain incompletely understood. Some molecular determinants of relapse have been identified in genomic, epigenetic and proteomic aberrations, while cellular relapse reservoirs have been identified in leukemia stem cells as well as in more mature leukemic cell compartments. Here, we set out to determine the cellular composition, gene mutation status and gene expression of paired AML specimens procured at diagnosis and at relapse aiming at a better understanding of the AML relapse process. Methods: We employed the drop-seq 3' single cell RNA sequencing (scRNA-seq) method (Macosko 2015) with minor modifications to analyze the mRNA expression in single cells derived from 12 paired AML specimens procured at diagnosis and at relapse from prior CR. We obtained scRNA-seq data on 1000-2000 single cells per sample detecting approximately 2000-3000 unique molecular identifiers (UMIs) and 800-1500 genes per cell. Using WES or panel-based sequencing we determined mutations in known driver genes. Subsequently, we optimized novel methods for detection and mapping of mutated driver genes to individual cells using mutation specific PCR conditions and novel bioinformatics approaches. We annotated scRNA-seq expression profiles of the diagnosis and relapsed AML specimens individually using publicly available data for cell type-specific RNA markers derived from sorted normal cell populations and further compared the scRNA-seq data to scRNA-seq data of 5 pooled normal human bone marrows generated for this study. Results: Through analyses of scRNA-seq data of paired diagnosis and relapse AML specimens via principle components analyses (PCA) or t-distributed stochastic neighbor embedding (t-SNE) we detected varying degrees of separation of cell clusters in all cases analyzed indicative of substantial changes in single cell gene expression between AML diagnosis and relapse. A few of these observed cluster shifts were paralleled by gain or loss of mutated genes (e.g. FLT3-ITD) at relapse while most others lacked obvious clonal genomic markers. Through subsequent comparison of the expression similarities of single AML cells to sorted normal human bone marrow cells we detected two distinct AML relapse patterns: i) a pattern of relapse suggesting simple leukemia regrowth as evidenced by similar proportions of leukemia cells mapping onto discrete normal bone marrow cells (e.g. monocyte-like or GMPs or CMPs), and, ii) a pattern of relapse whereby the gene expression of relapsed cells (but not diagnosis cells) had similarity to normal hematopoietic cells that are conventionally placed more apical in the classical hematopoiesis differentiation cascade (HSCs, MPPs, CMPs; a phenotypic shift to immaturity). In addition, no leukemia sample mapped to just one classically defined bone marrow cell type but instead to multiple cell types, suggesting that most AML leukemia cells harbor aberrant hybrid cell gene expression patterns. Finally, we detected quantitative shifts in T cells and NK cells in some samples at relapse, which will be analyzed in greater detail. Conclusions: The comparative analysis of scRNA-seq data of paired AML specimens procured at diagnosis and relapse, identifies frequent and previously unrecognized changes in gene expression in leukemia cells at relapse. Through a comparison of gene mutation and gene expression at single cell resolution we identify two distinct AML relapse patterns in adult AML. Disclosures No relevant conflicts of interest to declare.

Extramedullary Relapse of Acute Myelogenous Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation.

The clinical significance of extramedullary relapse (EMR) of acute myelogenous leukemia (AML) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains poorly defined. Here we report the clinical outcomes of patients who underwent allo-HSCT for AML at our institution between 2000 and 2012. A total of 293 patients with AML who underwent allo-HSCT were included. The median duration of follow-up in survivors was 1840 days. Disease status at the time of allo-HSCT was complete remission in 192 patients and nonremission in 101 patients. A total of 110 patients experienced AML relapse after allo-HSCT, including 18 with EMR only, 83 with bone marrow relapse (BMR) only, and 9 with both EMR and BMR. The 5-year cumulative incidence of EMR after allo-HSCT was 9.5%, whereas that of BMR only was 28.9%. In multivariate analysis, peripheral blood stem cell transplantation was associated with an increased risk of EMR. The 2-year overall survival after post-transplantation relapse was 7.5% in patients with BMR only, 11.1% in those with both EMR and BMR, and 27.5% in those with EMR only (P < .05). Although the short-term survival was better in patients with EMR only, they rarely achieved long-term survival. Appropriate strategies for both post-transplantation EMR and BMR are needed.

Biology-Driven Approaches to Prevent and Treat Relapse of Myeloid Neoplasia after Allogeneic Hematopoietic Stem Cell Transplantation.

The curative potential of allogeneic hematopoietic cell transplantation (allo-HCT) in the treatment of acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS) relies mainly on the graft-versus-leukemia effect. Relapse after allo-HCT occurs in a considerable proportion of patients and has a dismal prognosis, with still very limited curative potential. This review provides an overview of the established and evolving approaches to preventing or treating relapse of AML and MDS after allo-HCT, in the context of novel insight into the biology of relapse. Established prophylactic measures to prevent relapse include optimized conditioning and graft-versus-host disease (GVHD) prophylaxis, as well as donor lymphocyte infusion (DLI) for high-risk patients; novel immunomodulatory interventions and maintenance approaches are still experimental. Improved diagnostics can detect persistent or recurring disease at a molecular level, enabling early preemptive interventions. Established options include hypomethylating agents and DLI. Standard treatments for hematologic relapse include chemotherapy, cessation of immunosuppressive treatment, and DLI. Experimental approaches include molecular targeted therapies, novel immunomodulatory treatments, and second allo-HCT. For all interventions, the potential risks, including occurrence of GVHD, must be weighed against the benefits individually in each patient. Concurrently, prevention and treatment of relapse after allo-HCT remain challenging and unmet medical needs.

Low-Dose Azacitidine with DNMT1 Level Monitoring to Treat Post-Transplantation Acute Myelogenous Leukemia or Myelodysplastic Syndrome Relapse.

Patients with early relapse of acute myelogenous leukemia (AML) or myelodysplastic syndrome (MDS) after hematopoietic cell transplantation (HCT) have a poor prognosis, and no standard treatment. Twenty-nine patients with early disease recurrence post-transplantation were treated with azacitidine (AZA; median dose, 40 mg/m2/day for 5 to 7 days). At a median follow-up of 6.3 months (range, 1.3 to 41.1 months), 7 patients (27%) had a response to AZA, defined as complete remission, hematologic improvement, or improved donor chimerism. Response occurred after a median of 3 cycles, and the median duration of response was 70 days (range, 26 to 464 days). Median survival was 6.8 months (95% confidence interval, 3.8 to 11.1 months). Survival was similar in the patients receiving an AZA dose ≤40 mg/m2 and those receiving an AZA dose >40 mg/m2. Six patients receiving donor lymphocyte infusion with AZA had a response or stable disease without worsening graft-versus-host-disease. We retrospectively used a flow cytometry assay to explore DNA-methyltransferase-1 in blood mononuclear cells as a potential pharmacodynamic marker to assess intracellular drug targeting in 8 patients. No correlation with AZA dose or response was observed. Low-dose AZA appears to have comparable efficacy to higher-dose AZA post-HCT. A significant proportion of this poor-risk population responded to low-dose AZA, suggesting a dose-independent, noncytotoxic mechanism for antileukemic activity.

Enasidenib for the treatment of acute myeloid leukemia

ABSTRACTIntroduction: In August 2017, the United States Federal Drug Administration (FDA) approved enasidenib (Idhifa, Celgene/Agios) for adults with relapsed and refractory acute myelogenous leukemia (AML) with an IDH2 mutation. Enasidenib targets cells with mutant copies of isocitrate dehydrogenase-2 (IDH2), inhibiting the oncometabolite 2-hydroxyglutarte (2-HG) formed by the mutant IDH2.Areas covered: We review the studies leading to enasidenib’s approval, as well as common side effects and safety issues experienced during the clinical trials. There is a focus on the diagnosis and treatment of these side effects including differentiation syndrome.Expert commentary: We are experiencing a revolution in the understanding of the mechanism of AML. A majority of the effort has been concentrated on targeting gene mutations or pathway activations with precision therapeutics. Enasidenib is beneficial in a patient population that previously had limited treatment options. However, given the fact that enasidenib is a highly specific inhibitor of an early stable mutation, it is questionable whether a strategy of targeting a single mutation or pathway in relapsed AML will allow for better than the 20% complete remission (CR) rate observed with this therapy. The proper role for single mutation targeting in AML needs to be carefully considered.

Reversal of T Cell Exhaustion by the First Donor Lymphocyte Infusion Is Associated with the Persistently Effective Antileukemic Responses in Patients with Relapsed AML after Allo-HSCT

Donor lymphocyte infusion (DLI) is an effective approach to treat acute myelogenous leukemia (AML) relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT) that significantly improves the survival of relapsed patients. However, the mechanism of an effective antileukemic response following DLI in AML relapse remains elusive. Here, we investigated the role of T cell exhaustion in AML relapse after allo-HSCT in prospective cohorts of 41 patients with the first AML relapse and 41 nonrelapsed AML control subjects after allo-HSCT and determined whether DLI exerts effective antileukemic effects by reversing T cell exhaustion in the relapsed cohorts by detecting the phenotypes and functions of T cells using flow cytometry. We found that both CD4+ and CD8+ T cells experienced exhaustion with upregulated coexpression of PD-1 and Tim-3, and functional impairments in cytokine production, proliferation, and cytotoxic potentials. The reversal of T cell exhaustion by the first DLI is associated with persistent complete remission in relapsed AML patients. In addition, the reversal of T cell–exhausted status after successful DLI in bone marrow was concurrent with the mitigated inversion of CD4/CD8 T cell ratio. In conclusion, our study shows a clinical correlation between T cell exhaustion and AML relapse after allo-HSCT, and uncovers the role of reversing T cell exhaustion in the antileukemic response by DLI and identifies possible immunological markers to evaluate and predict the graft-versus-leukemia effects induced by DLI.

Evolution of Cancer Stem Cells in Acute Myelogenous Leukemia and Targeting Via Novel Nanotechnology Approaches

The cancer stem cell model is a hierarchical representation of the asymmetric division of cancer stem cells to form transit-amplifying cells, and ultimately differentiated cancer cells. The model can be applied to Acute Myelogenous Leukemia (AML), a hematopoieticderived cancer. A single tumor population of AML is composed of a minor cancer stem cell subpopulation as well as the majority transit-amplifying cell population. Following treatment of AML with chemotherapy and radiation, the tumors repopulate, as the cancer stem cells remain to regrow the transit-amplifying cell population. This is supported by evidence of an increased number of cancer stem cell markers following relapse of AML, such as CD34, CD38, and CD45 surface markers. Cancer stem cells are therefore the focus of targeted cancer therapies, such as novel nanotechnology drug approaches, which improve speed and accuracy of drug delivery.