Ubiquitin-Derived Fragment as a Peptide Linker for the Efficient Cleavage of a Target Protein from a Degron

The chemogenetic control of cellular protein stability using degron tags is a powerful experimental strategy in biomedical research. However, this technique requires permanent fusion of the degron to a target protein, which may interfere with the proper function of the protein. Here, we report a peptide fragment from the carboxyl terminus of ubiquitin as a cleavable linker that exhibits the slow but efficient cleavage of a degron tag via cellular deubiquitinating enzymes (DUBs). We designed a fusion protein consisting of a cleavable linker and a destabilizing domain (DD), which conditionally controls the expression and release of a target protein in a ligand-induced state, allowing the free unmodified protein to perform its function. Insertion of an AGIA epitope at the carboxyl terminus of the linker made space for the DUBs to access the site to assist the cleavage reaction when the amino terminus of the target protein caused steric hindrance. The developed system, termed a cleavable degron using ubiquitin-derived linkers (c-DUB), provides robust and tunable regulation of target proteins in their native forms. The c-DUB system is a useful tool for the regulation of proteins that have terminal sites that are essential for the proper localization and function. In addition, a mechanistic investigation using proximity labeling showed that DUBs associate with the refolded DD to reverse ubiquitination, suggesting a cellular surveillance system for distinguishing the refolded DD from misfolded proteins. The c-DUB method may benefit from this machinery so that DUBs subsequently cleave the neighboring linker.

A strategy for orthogonal deubiquitination using a bump-and-hole approach

We have successfully applied a bump-and-hole approach to establish orthogonal deubiquitination in which a ubiquitin substrate variant is specifically targeted by an engineered deubiquitinating enzyme (DUB). This makes it possibe to selectively observe and measure a single type of DUB activity in living cells.

Entomopathogenic fungus Beauveria bassiana-based bioinsecticide suppresses severity of powdery mildews of vegetables by inducing the plant defense responses

The entomopathogenic fungus Beauveria bassiana is used commercially as a microbial insecticides against a wide range of agricultural insect pests. Some strains of B. bassiana protect the plants from pathogens, but the underlying mechanisms are largely unknown. Here, we found that prophylactic sprays of commercial bioinsecticide Botanigard on cucumber, tomato, and strawberry plants suppressed the severity of economically damaging powdery mildews. On leaf surfaces, hyphal elongation and spore germination of cucumber powdery mildew, Podosphaera xanthii, were inhibited, but B. bassiana strain GHA, the active ingredient isolated from Botanigard, only inhibited hyphal elongation but had no effect on spore germination of P. xanthii. In addition, strain GHA suppressed powdery mildew symptoms locally, not systemically. Treatment with Botanigard and strain GHA induced a hypersensitive response (HR)-like cell death in epidermal cells of the cucumber leaves in a concentration-dependent manner and inhibited penetration by P. xanthii. Transcriptome analysis and mass spectrometry revealed that GHA induced expression of salicylic acid (SA)-related genes, and treatment with Botanigard and GHA increased the SA level in the cucumber leaves. In NahG-transgenic tomato plants, which do not accumulate SA, the biocontrol effect of tomato powdery mildew by GHA was significantly reduced. These results suggested that B. bassiana GHA induces SA accumulation, leading to the induction of HR-like cell death against powdery mildew and subsequent suppression of fungal penetration. Thus, Botanigard has the potential to control both insect pests and plant diseases.

Lenalidomide derivatives and proteolysis-targeting chimeras for controlling neosubstrate degradation

Lenalidomide, an immunomodulatory drug (IMiD), is commonly used as a first-line therapy in many haematological cancers, such as multiple myeloma (MM) and 5q myelodysplastic syndromes (5q MDS), and it functions as a molecular glue for the protein degradation of neosubstrates by CRL4CRBN. Proteolysis-targeting chimeras (PROTACs) using IMiDs with a target protein binder also induce the degradation of target proteins. The targeted protein degradation (TPD) of neosubstrates is crucial for IMiD therapy. However, current IMiDs and IMiD-based PROTACs also break down neosubstrates involved in embryonic development and disease progression. Here, we show that 6-position modifications of lenalidomide are essential for controlling neosubstrate selectivity; 6-fluoro lenalidomide induced the selective degradation of IKZF1, IKZF3, and CK1α, which are involved in anti-haematological cancer activity, and showed stronger anti-proliferative effects on MM and 5q MDS cell lines than lenalidomide. PROTACs using these lenalidomide derivatives for BET proteins induce the selective degradation of BET proteins with the same neosubstrate selectivity. PROTACs also exert anti-proliferative effects in all examined cell lines. Thus, 6-position-modified lenalidomide is a key molecule for selective TPD using thalidomide derivatives and PROTACs.

Safety and efficacy of high-dose cytarabine MEAM therapy and other treatments for auto-peripheral blood stem cell transplantation: A retrospective comparative study

AIM

The MEAM regimen consisting of ranimustine (MCNU), etoposide (ETP), cytarabine (Ara-C), and melphalan (MEL) is widely used before auto-peripheral blood stem cell transplantation (auto-PBSCT) for malignant lymphoma in Japan. The MEAM regimen generally consists of 200-400 mg/m² for 4 days, but we decided to increase the dosage of Ara-C from the standard to 2 g/m² for 2 days with the aim of increasing drug transferability to the central nervous system. We evaluate the safety and therapeutic efficacy of high-dose Ara-C MEAM therapy.

METHODS

The high-dose Ara-C MEAM protocol consisted of MCNU 300 mg/m² on day -7, ETP 200 mg/m² on days -6, -5, -4, -3 and Ara-C 2 g/m² on day -4 -3, and MEL 140 mg/m² on day -2. We retrospectively analyzed 37 cases of malignant lymphoma at our institution between May 2014 and July 2020.

RESULTS

All patients got engraftment and there were no cases of treatment-related mortality. In all cases, the 3-year overall survival (OS) and progression-free survival (PFS) after transplantation were 80.6% and 65.7%, respectively. Twenty-one cases of diffuse large B-cell lymphoma recurrence, for which there is proven usefulness of auto-PBSCT, showed good results after transplantation, with the 3-year OS and PFS after transplantation being 100% and 74.3%, respectively.

CONCLUSION

The safety and efficacy of high-dose Ara-C MEAM therapy were demonstrated, but the expected therapeutic effect on central nervous system lesions could not be fully evaluated owing to the small number of cases.

A proximity biotinylation-based approach to identify protein-E3 ligase interactions induced by PROTACs and molecular glues

Proteolysis-targeting chimaeras (PROTACs) as well as molecular glues such as immunomodulatory drugs (IMiDs) and indisulam are drugs that induce interactions between substrate proteins and an E3 ubiquitin ligases for targeted protein degradation. Here, we develop a workflow based on proximity-dependent biotinylation by AirID to identify drug-induced neo-substrates of the E3 ligase cereblon (CRBN). Using AirID-CRBN, we detect IMiD-dependent biotinylation of CRBN neo-substrates in vitro and identify biotinylated peptides of well-known neo-substrates by mass spectrometry with high specificity and selectivity. Additional analyses reveal ZMYM2 and ZMYM2-FGFR1 fusion protein-responsible for the 8p11 syndrome involved in acute myeloid leukaemia-as CRBN neo-substrates. Furthermore, AirID-DCAF15 and AirID-CRBN biotinylate neo-substrates targeted by indisulam and PROTACs, respectively, suggesting that this approach has the potential to serve as a general strategy for characterizing drug-inducible protein-protein interactions in cells.

Phylogenetic placements and cultural characteristics of Tuber species isolated from ectomycorrhizas

Pure cultures of Tuber were isolated from ectomycorrhizal root tips in Abies sachalinensis plantations in Hokkaido, Japan. Their phylogenetic relationships as well as vegetative hyphal characteristics on culture media were reported. Phylogenetic analysis based on the internal transcribed spacer within ribosomal DNA settled well-supported eight lineages within Puberulum, Latisporum, and Maculatum clades in Tuber. Three and one lineages were grouped with undescribed species of Puberulum clade in Japan and that of the Latisporum group in China, respectively. Two lineages were closely associated to but distinct from an undescribed species of Puberulum clade in Japan. One lineage did not group with any sequences in the International Nucleotide Sequence Database (INSD), proposing a new taxon in the Latisporum group. One lineage was grouped with T. foetidum in Maculatum clade. All strains in each lineage displayed yellowish white, thin, filamentous colonies on Melin-Norkrans agar medium. Various differences in morphological characteristics of hyphae on pure cultures of various strains were noted, but they were frequently uncommon among strains of the same taxa. Isolation from ectomycorrhizal root tips can be among the effective ways to acquire pure cultures of Tuber strains.

Presence of Promyelocytes in Peripheral Blood as a Novel Predictor of Optimal Timing for Single-Step Peripheral Blood Stem Cell Collection

BACKGROUND

Because peripheral blood stem cell (PBSC) collection places a burden on the patient and should ideally be completed in a single procedure, a convenient clinical predictive factor is needed.

METHODS

This retrospective study included 72 patients who underwent autologous PBSC collection. A median volume of 3.9 × 10⁶ CD34-positive cells/kg (range: 0.3-47.4 × 10⁶ cells/kg) was collected on the first day. We defined failure as inability to collect 2.0 × 10⁶ cells/kg on the first day. PBSC collection was classified as failed (n = 25, 34.7%) and successful (n = 47, 65.3%), and patient clinical characteristics were analyzed.

RESULTS

The success group had significantly more cases in which a differential white blood cell count in peripheral blood on the day of PBSC collection detected promyelocytes (n = 34 [72.3%] vs. n = 11 [44.0%] in the failure group; P = 0.008). Sixty-two patients underwent autologous PBSC transplantation (median number of transplanted cells, 5.6 × 10⁶/μL; range: 1.60-47.4 × 10⁶ cells/μL). Among transplanted patients, the success and failure groups did not significantly differ in relation to the interval until neutrophil, platelet, or red blood cell engraftment.

CONCLUSION

The presence of promyelocytes in peripheral blood may be a useful indicator of the optimal timing for single-step PBSC collection.

Thalidomide and its metabolite 5-hydroxythalidomide induce teratogenicity via the cereblon neosubstrate PLZF

Thalidomide causes teratogenic effects by inducing protein degradation via cereblon (CRBN)‐containing ubiquitin ligase and modification of its substrate specificity. Human P450 cytochromes convert thalidomide into two monohydroxylated metabolites that are considered to contribute to thalidomide effects, through mechanisms that remain unclear. Here, we report that promyelocytic leukaemia zinc finger (PLZF)/ZBTB16 is a CRBN target protein whose degradation is involved in thalidomide‐ and 5‐hydroxythalidomide‐induced teratogenicity. Using a human transcription factor protein array produced in a wheat cell‐free protein synthesis system, PLZF was identified as a thalidomide‐dependent CRBN substrate. PLZF is degraded by the ubiquitin ligase CRL4^CRBN in complex with thalidomide, its derivatives or 5‐hydroxythalidomide in a manner dependent on the conserved first and third zinc finger domains of PLZF. Surprisingly, thalidomide and 5‐hydroxythalidomide confer distinctly different substrate specificities to mouse and chicken CRBN, and both compounds cause teratogenic phenotypes in chicken embryos. Consistently, knockdown of Plzf induces short bone formation in chicken limbs. Most importantly, degradation of PLZF protein, but not of the known thalidomide‐dependent CRBN substrate SALL4, was induced by thalidomide or 5‐hydroxythalidomide treatment in chicken embryos. Furthermore, PLZF overexpression partially rescued the thalidomide‐induced phenotypes. Our findings implicate PLZF as an important thalidomide‐induced CRBN neosubstrate involved in thalidomide teratogenicity.

Electronic and spin structures of CaMn4Ox clusters in the S0 state of the oxygen evolving complex of photosystem II. Domain-based local pair natural orbital (DLPNO) coupled-cluster (CC) calculations using optimized geometries and natural orbitals (UNO) by hybrid density functional theory (HDFT) calculations

Domain-based local pair natural orbital (DLPNO) coupled cluster single and double (CCSD) with triple perturbation (T) correction methods were performed to elucidate the relative stabilities of ten different intermediate structures of the CaMn4Ox cluster in the S0 state of the oxygen evolving complex (OEC) of photosystem II (PSII). Full geometry optimizations of all the S0 intermediates were performed by the UB3LYP-D3/Def2-TZVP methods, providing the assumed geometrical structures and starting natural orbitals (UNO) for DLPNO-CCSD(T)/Def2TZVP calculations. The effective exchange integrals (J) for the spin Hamiltonian models for the ten intermediates were obtained by the UB3LYP/Def2-TZVP calculations followed by the general spin projections. DLPNO-CCSD(T) calculations followed by the CBS extrapolation procedure elucidated that the (II, III, IV, IV) and (III, III, III, IV) valence states in the CaMn4O5 cluster of the OEC of the PS II were nearly degenerated in energy in the S0 state, indicating an important role of dynamical electron correlation effects for the valence and spin fluctuations in strongly correlated electron systems (SCESs) consisting of 3d transition metals.

Central Nervous System-related Graft-versus-host Disease after Allogeneic Hematopoietic Stem Cell Transplantation

Allogeneic hemopoietic stem cell transplantation (allo-HSCT) is the only curative therapy for refractory hematological malignancies. However, there are many treatment-related complications, including organ disorders, graft-versus-host disease (GVHD), and infectious diseases. Furthermore, there are many unclear points regarding central nervous system (CNS) complications, and the prognosis in patients with CNS complications is extremely poor. We herein report a 49-year-old woman who developed CNS-GVHD after a second transplantation for therapy-related myelodysplastic syndrome. CNS-GVHD in this case was refractory to all treatments, including steroids, and progressed. We also present a review of the literature about the symptoms, diagnosis, and treatment of CNS-GVHD.

Association of Education and Depressive Symptoms with Tooth Loss

Previous evidence suggests the association of lower educational attainment and depressive symptoms with tooth loss. The hypothesis of this study was that these factors may exacerbate the effect on tooth loss beyond the sum of their individual effects. We aimed to clarify the independent and interactive effects of educational attainment and depressive symptoms on the number of missing teeth among community residents. Cross-sectional data of 9,647 individuals were collected from the general Japanese population. Dental examination was conducted by dentists. Educational attainment was categorized into 3 levels based on the number of educational years: ≤9, >9 to ≤12, and >12 y. The Center for Epidemiologic Studies Depression Scale (CES-D) was used to assess depressive symptoms; a total score of ≥16 and/or the use of medications for depression indicate the presence of depressive symptoms. In the multivariate analysis with adjustment for conventional risk factors, educational attainment was identified as a determinant of the number of missing teeth (>9 to ≤12 y of education: coefficient = 0.199, 95% confidence interval [CI], 0.135 to 0.263, P < 0.001; ≤9 y of education: coefficient = 0.318, 95% CI, 0.231 to 0.405, P < 0.001: reference, >12 y of education). An analysis that included interaction terms revealed that the relationship between "≤9 y of education" and the number of missing teeth differed depending on the depressive symptoms, indicating a positive interactive association (coefficient for interaction = 0.198; 95% CI, 0.033 to 0.364, P for interaction = 0.019: reference, >12 y of education). Our study suggests the presence of a significant association between educational attainment and tooth loss, as well as a partial interactive association between "≤9 y of education" and "depressive symptoms" in the general Japanese population.

Long-term outcomes of Japan-specific dosage of rivaroxaban in high-risk patients with non-valvular atrial fibrillation: analysis from the XAPASS

Background

XAPASS is a real-world, prospective, single-arm, observational study conducted as a post-marketing surveillance mandated by the health authority in Japan. Nowadays, direct oral anticoagulant therapy using factor Xa or thrombin inhibitor has been the standard of care for patients with non-valvular atrial fibrillation (NVAF) to prevent ischemic stroke. However, the clinical impact of reduced dosage (approved dose of 15 or 10 mg once daily in Japan is relatively reduced compared to global dosage) factor Xa inhibitor rivaroxaban in high-risk patients remains unclear.

Purpose

The present sub-analysis of XAPASS was carried out to assess long-term safety and effectiveness of reduced-dose rivaroxaban in high-risk NVAF patients for bleeding and thromboembolism.

Methods

All patients with NVAF who were newly started on rivaroxaban were eligible for surveillance. The principal safety outcome was a composite of major and non-major bleeding events, and the primary effectiveness outcome was a composite of ischaemic stroke, haemorrhagic stroke, non-central nervous system systemic embolism (non-CNS SE), and myocardial infarction (MI). In this present sub-analysis, high-risk patients were defined as those who had two of the following three risk factors: elderly (≥75 years old), low body weight (≤50 kg), and renal impairment (CrCl &lt;50 mL/min).

Results

In total, 11,308 patients were enrolled between April 2012 and June 2014 from 1,419 hospitals, and overall data were analysed from 10,664 patients from whom data were collected. Among them, 3,694 patients matched the criteria for the high-risk patients defined in this sub-analysis, and 6,970 patients did not match the criteria (non-high-risk patients). The mean treatment duration was 791±673 days in the high-risk patients and 944±709 days in the non-high-risk patients. Mean patient age was 80.9±5.5 years and 69.0±9.0 years at baseline, respectively. Mean CHADS2 score was 2.8 and 1.8, and CHA2DS2-VASc score was 4.4 and 2.9, respectively. The rates of CHADS2 component comorbidities were lower in the non-high-risk patients except for diabetes mellitus. The incidence rates of any bleeding, major bleeding, and the primary effectiveness outcomes were 4.8, 1.6, and 2.1%/patient-year in the high-risk patients. The incidence rates of these clinical events in the non-high-risk patients were 3.3, 0.9, and 1.0%/patient-year, respectively.

Conclusions

Incidence rates of long-term bleeding and thromboembolism were higher in the high-risk patients than in the non-high-risk patients. However, the rates of these outcomes using the Japan-specific reduced dose were not so high. Furthermore, the balance between safety and effectiveness outcomes was within an acceptable range. The present study provides useful information for physicians to stratify high-risk patients using the reduced dose in daily clinical practice.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Bayer Yakuhin Ltd.

Structural bases of IMiD selectivity that emerges by 5-hydroxythalidomide

Thalidomide and its derivatives exert not only therapeutic effects as immunomodulatory drugs (IMiDs) but also adverse effects such as teratogenicity, which are due in part to different C2H2 zinc-finger (ZF) transcription factors, IKZF1 (or IKZF3) and SALL4, respectively. Here, we report the structural bases for the SALL4-specific proteasomal degradation induced by 5-hydroxythalidomide, a primary thalidomide metabolite generated by the enzymatic activity of cytochrome P450 isozymes, through the interaction with cereblon (CRBN). The crystal structure of the metabolite-mediated human SALL4-CRBN complex and mutagenesis studies elucidate the complex formation enhanced by the interaction between CRBN and an additional hydroxy group of (S)-5-hydroxythalidomide and the variation in the second residue of β-hairpin structure that underlies the C2H2 ZF-type neo-morphic substrate (neosubstrate) selectivity of 5-hydroxythalidomide. These findings deepen our understanding of the pharmaceutical action of IMiDs and provide structural evidence that the glue-type E3 ligase modulators cause altered neosubstrate specificities through their metabolism.

Outcomes of Patients with Early Hyperbilirubinemia after Allogeneic Hematopoietic Stem Cell Transplantation

BACKGROUND

Because the cause of liver dysfunction after allogeneic hematopoietic stem cell transplantation (HSCT) is difficult to identify in the early stages, treatment may be delayed. Therefore, early factors associated with unfavorable outcomes of liver dysfunction must be identified. The objective of this study was to identify unfavorable prognostic factors for liver dysfunction during the early period after transplantation.

METHODS

We defined liver dysfunction as elevated liver or biliary enzyme levels (corresponding to Grade 2 in the Common Terminology Criteria for Adverse Events version 4.0) within 30 days of transplantation and retrospectively investigated data from 82 patients who had undergone allogeneic HSCT at our center.

RESULTS

Elevated liver or biliary enzyme levels were observed in almost half of the patients studied (n=40, 48.7%). Elevated total bilirubin (T-Bil) level was the most frequently observed unfavorable prognostic factor and had the greatest effect on overall survival (OS), progression-free survival (PFS), and non-relapse mortality (NRM) (probability of unfavorable outcome in patients without and with elevated T-Bil level: OS, 58.9% vs. 15.4%, p < 0.001; PFS, 46.4% vs. 15.4%, p < 0.001; NRM, 10.7% vs. 53.8%, p < 0.001). Moreover, the probability of an unfavorable outcome increased in relation to the degree of T-Bil elevation and absence of improvement over time in T-Bil level.

CONCLUSION

Elevated T-Bil level was an important marker of outcomes for liver dysfunction after allogeneic HSCT.

AirID, a novel proximity biotinylation enzyme, for analysis of protein-protein interactions

Proximity biotinylation based on Escherichia coli BirA enzymes such as BioID (BirA*) and TurboID is a key technology for identifying proteins that interact with a target protein in a cell or organism. However, there have been some improvements in the enzymes that are used for that purpose. Here, we demonstrate a novel BirA enzyme, AirID (ancestral BirA for proximity-dependent biotin identification), which was designed de novo using an ancestral enzyme reconstruction algorithm and metagenome data. AirID-fusion proteins such as AirID-p53 or AirID-IκBα indicated biotinylation of MDM2 or RelA, respectively, in vitro and in cells, respectively. AirID-CRBN showed the pomalidomide-dependent biotinylation of IKZF1 and SALL4 in vitro. AirID-CRBN biotinylated the endogenous CUL4 and RBX1 in the CRL4^CRBN complex based on the streptavidin pull-down assay. LC-MS/MS analysis of cells that were stably expressing AirID-IκBα showed top-level biotinylation of RelA proteins. These results indicate that AirID is a novel enzyme for analyzing protein–protein interactions.

Proteins in a cell need to interact with each other to perform the many tasks required for organisms to thrive. A technique called proximity biotinylation helps scientists to pinpoint the identity of the proteins that partner together. It relies on attaching an enzyme (either BioID or TurboID) to a protein of interest; when a partner protein comes in close contact with this construct, the enzyme can attach a chemical tag called biotin to it. The tagged proteins can then be identified, revealing which molecules interact with the protein of interest.

Although BioID and TurboID are useful tools, they have some limitations. Experiments using BioID take more than 16 hours to complete and require high levels of biotin to be added to the cells. TurboID is more active than BioID and is able to label proteins within ten minutes. However, under certain conditions, it is also more likely to be toxic for the cell, or to make mistakes and tag proteins that do not interact with the protein of interest.

To address these issues, Kido et al. developed AirID, a new enzyme for proximity biotinylation. Experiments were then conducted to test how well AirID would perform, using proteins of interest whose partners were already known. These confirm that AirID was able to label partner proteins in human cells; compared with TurboID, it was also less likely to mistakenly tag non-partners or to kill the cells, even over long periods.

The results by Kido et al. demonstrate that AirID is suitable for proximity biotinylation experiments in cells. Unlike BioID and TurboID, the enzyme may also have the potential to be used for long-lasting experiments in living organisms, since it is less toxic for cells over time.

Impact of body mass index on real-world outcomes of rivaroxaban treatment in Japanese patients with non-valvular atrial fibrillation

This sub-analysis of the XAPASS, a prospective, single-arm, observational study, aimed to evaluate relationships between body mass index (BMI) and safety (major bleeding and all-cause mortality) and effectiveness [stroke/non-central nervous system (non-CNS) systemic embolism (SE)/myocardial infarction (MI)] outcomes in Japanese patients with non-valvular atrial fibrillation (NVAF) receiving rivaroxaban. Patients were categorized according to BMI (kg/m²) as underweight (< 18.5), normal weight (18.5 to < 25), overweight (25 to < 30), or obese (≥ 30). In total, 9578 patients with NVAF completed the 1-year follow-up and were evaluated; of these, 7618 patients had baseline BMI data. Overall, 542 (5.7%), 4410 (46.0%), 2167 (22.6%), and 499 (5.2%) patients were underweight, normal weight, overweight, and obese, respectively. Multivariable Cox regression analysis demonstrated that none of the BMI categories were independent predictors of major bleeding whereas being underweight was independently associated with increased all-cause mortality [hazard ratio (HR) 3.56, 95% confidence interval (CI) 2.40–5.26, p < 0.001]. The incidence of stroke/non-CNS SE/MI was higher in patients who were underweight than in those of normal weight (HR 2.11, 95% CI 1.20–3.70, p = 0.009). However, in multivariable analyses, being underweight was not identified as an independent predictor of stroke/non-CNS SE/MI (HR 1.64, 95% CI 0.90–2.99, p = 0.104). In conclusion, the high incidence of thromboembolic events and all-cause mortality in patients who were underweight highlights that thorough evaluation of disease status and comorbidities may be required in this population.

Outcomes associated with under-dosing of rivaroxaban for management of non-valvular atrial fibrillation in real-world Japanese clinical settings

The approved dose of oral anticoagulant rivaroxaban for patients with non-valvular atrial fibrillation (NVAF) in Japan is 15 mg once daily (od) in patients whose creatinine clearance is ≥ 50 mL/min, but recent real-world studies have demonstrated that these patients often received less than the recommended dose due to bleeding concerns. The effect of under-dosing on safety and effectiveness outcomes remains unclear. We used 1-year follow-up data from the XAPASS, a real-world Japanese prospective, single-arm, observational study. Of the 11,308 patients, 6521 patients who completed a 1-year follow-up and had a creatinine clearance ≥ 50 mL/min were included in this sub-analysis. Primary endpoints were any bleeding and a composite of stroke/non-central nervous system systemic embolism (non-CNS SE)/myocardial infarction (MI). Among the 6521 patients, 4185 (64.2%; mean CHADS₂ score: 1.8) received the 15 mg od (recommended dose), whereas 2336 (35.8%; mean CHADS₂ score: 2.3) received 10 mg od (under-dose). After adjusting for patient characteristics by propensity scoring and inverse probability of treatment weighting, incidence rates of major bleeding were comparable between under-dosed patients and patients who received the recommended dose (1.34 vs. 1.63 events/100 patient-years, p = 0.197), although the incidence rates of stroke/non-CNS SE/MI were higher in under-dosed patients than in those who received the recommended dose (2.15 vs. 1.48 events/100 patient-years, p = 0.009). In Japanese clinical practice, some NVAF patients receive rivaroxaban doses inconsistent with the recommendation. Considering the total clinical benefit, the recommended dose may be preferable in terms of balance of safety and effectiveness.Clinicaltrials.gov NCT01582737.

Real-world outcomes of rivaroxaban treatment in elderly Japanese patients with nonvalvular atrial fibrillation

Direct oral anticoagulants (DOACs), such as rivaroxaban, reduce the risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation (NVAF). However, it is still unclear whether the stroke reduction benefit outweighs the bleeding risk in elderly Japanese patients with NVAF. The Xarelto Post-Authorization Safety and Effectiveness Study in Japanese Patients with Atrial Fibrillation (XAPASS) was a real-world, prospective observational, post-marketing surveillance study on the safety and effectiveness of rivaroxaban in Japanese clinical practice. This sub-analysis evaluated the clinical outcomes of elderly patients aged ≥ 75 years. At the 1-year follow-up, there were 4,685 (48.91%) and 4,893 (51.09%) patients aged ≥ 75 and < 75 years, respectively. Safety and effectiveness outcomes were compared between patients aged ≥ 75 years and those aged < 75 years, and among 3 elderly sub-populations (age ranges: 75-79, 80-84, and ≥ 85 years). Patients aged ≥ 75 years had higher rates of major bleeding [2.22 vs. 1.35 events per 100 patient-years, hazard ratio (HR) 1.63, 95% confidence interval (CI) 1.17-2.28] and composite of stroke (ischemic or hemorrhagic)/non-central nervous system (non-CNS) systemic embolism (SE)/myocardial infarction (MI) (2.41 vs. 1.21 events per 100 patient-years, HR 1.97, 95% CI 1.40-2.77) compared to patients aged < 75 years. Intracranial hemorrhage rates were < 1 event per 100 patient-years in both groups (0.85 vs. 0.59 events per 100 patient-years, HR 1.43, 95% CI 0.85-2.40). Kaplan-Meier curves of major bleeding and stroke/non-CNS SE/MI showed that no significant differences of cumulative event rates were identified among the 3 elderly sub-populations. Stepwise Cox regression analyses revealed that creatinine clearance (CrCl) (<50 mL/min), hepatic impairment, and hypertension were specific predictors for major bleeding and no specific predictors were found for stroke/non-CNS SE/MI in patients aged ≥ 75 years. In conclusion, safety and effectiveness event rates were higher in patients aged ≥ 75 years compared with those aged < 75 years, yet, no distinct differences were observed among the 3 elderly sub-populations.

Risk Factors for Acute Kidney Injury and Chronic Kidney Disease following Allogeneic Hematopoietic Stem Cell Transplantation for Hematopoietic Malignancies

BACKGROUND

Acute kidney injury (AKI) and chronic kidney disease (CKD) are considered common complications after allogeneic hematopoietic stem cell transplantation (allo-HSCT).

OBJECTIVES AND METHOD

In this study, 114 patients who had undergone allo-HSCT were retrospectively analyzed to investigate the risk factors for onset of posttransplant AKI and CKD as defined by the new Kidney Disease Improving Global Outcomes criteria.

RESULTS

Seventy-four patients (64.9%) developed AKI and 25 (21.9%) developed CKD. The multivariate analysis showed that the risk factors for developing stage 1 or higher AKI were age ≥46 years at the time of transplant (p = 0.001) and use of ≥3 nephrotoxic drugs (p = 0.036). For CKD, the associated risk factors were disease status other than complete remission at the time of transplantation (p = 0.018) and onset of AKI after transplant (p = 0.035). The 5-year overall survival (OS) was significantly reduced by development of AKI (p < 0.001), but not CKD. Posttransplant AKI significantly increased the 5-year nonrelapse mortality (p < 0.001), whereas posttransplant CKD showed an increasing tendency, but the difference was not significant.

CONCLUSIONS

Posttransplant AKI impacts OS, significantly increases the risk of CKD, and is significantly associated with disseminated intravascular coagulation and use of ˃3 nephrotoxic drugs.

Real-World Outcomes of Rivaroxaban Treatment in Patients with Both Nonvalvular Atrial Fibrillation and a History of Ischemic Stroke/Transient Ischemic Attack

Introduction: Prior stroke is a risk factor for stroke and bleeding during anticoagulation in patients with atrial fibrillation (AF). Although rivaroxaban is widely prescribed to reduce their risk of stroke in patients with nonvalvular AF (NVAF), the real-world evidence on rivaroxaban treatment is limited. We aimed to examine the outcomes of rivaroxaban treatment in NVAF patients with prior ischemic stroke/transient ischemic attack (TIA) by using the data of the Xarelto Post-Authorization Safety and Effectiveness Study in Japanese ­Patients with AF, a prospective, single-arm, observational study. Methods: The clinical outcomes of 9,578 patients who completed the 1-year follow-up were evaluated. Safety and effectiveness outcomes were compared between patients with and without prior ischemic stroke/TIA. Results: Among the patients, 2,153 (22.5%) had prior ischemic stroke/TIA. They were significantly older and had lower body weight, lower creatinine clearance, higher CHADS2, CHA2DS2-VASc, and modified HAS-BLED scores as compared to those without prior ischemic stroke/TIA. Any bleeding (9.1 vs. 7.2 events per 100 patient-years), major bleeding (2.3 vs. 1.6 events per 100 patient-years), and stroke/non-central nervous system systemic embolism/myocardial infarction (3.4 vs. 1.3 events per 100 patient-years) were more frequent in patients with prior ischemic stroke/TIA. Stepwise regression analysis suggested that body weight of ≤50 kg and diabetes mellitus were predictive of major bleeding in patients with prior ischemic stroke/TIA. Conclusions: Safety and effectiveness event rates were higher in patients with prior ischemic stroke/TIA than those without. This might be explained by differences in several risk profiles including age, body weight, renal function, and risk scores such as CHADS2 between the groups. Clinicaltrials.gov: NCT01582737.

P6337Prognostic impacts of serum uric acid levels in patients with chronic heart failure: insights from the CHART-2 Study

Background

Prognostic impact of serum uric acid (UA) levels in patients with heart failure (HF) remains to be fully elucidated, as previous studies were inconclusive with small study sample sizes. Furthermore, although the J-curve relationship between serum UA levels and cardiovascular events has been suggested in patients with hypertension and those with diabetes, it is still unclear whether this is also the case for patients with HF.

Purpose

We examined the prognostic impacts of serum UA levels in HF patients, using the database of our Chronic Heart Failure Registry and Analysis in the Tohoku district (CHART)-2 Study, the largest multicenter, prospective, observational cohort study for cardiovascular patients with HF or those at risk of HF in Japan (N=10,219).

Methods

First, we determined the cut-off value of serum UA levels at baseline by the Classification and Regression Tree (CART). Then, we divided 4,652 consecutive HF patients in the CHART-2 Study into 4 groups; G1 (<3.8 mg/dL, N=313), G2 (3.8–7.1 mg/dL, N=3,070), G3 (7.2–9.2 mg/dL, N=1,018), and G4 (≥9.3 mg/dL, N=251). Among the 4 groups, we compared clinical characteristics and incidence of all-cause death, HF hospitalization, and a composite of all-cause death and HF hospitalization.

Results

Mean age in G1, G2, G3, and G4 was 71±12, 69±12, 68±13, and 69±15 years, respectively (P<0.001). G1 was characterized by a significantly high prevalence of women as compared with G2, G3 and G4 (59, 32, 24 and 23%, respectively). Serum creatinine levels (0.8±0.4, 0.9±0.4, 1.2±0.6 and 1.4±0.8 mg/dL, respectively), prevalence of atrial fibrillation (34, 39, 45 and 50%, respectively), and diuretics use (36, 45, 67, 89%, respectively) increased from G1, G2, G3 to G4 (all P<0.001), while left ventricular ejection fraction decreased from G1, G2, G3 to G4 (59±15, 58±15, 54±15, and 52±17%, respectively, P<0.001). Median BNP levels were comparably low in G1 and G2 and then increased to G3 and G4 (94.4, 91.5, 130 and 192.5 pg/mL, respectively, P<0.001). As a HF etiology, prevalence of ischemic heart disease was highest in G2 and lowest in G4 (48, 52, 48, 38%, respectively, P<0.001), while that of dilated cardiomyopathy increased from G1, G2, G3 to G4 (11, 12, 16 and 20%, respectively, P<0.001). During the median follow-up period of 6.3 years, in G1, G2, G3 and G4, 111 (35%), 905 (29%), 370 (36%) and 139 (55%) patients died and 79 (25%), 729 (24%), 300 (29%) and 115 (46%) experienced HF hospitalization, respectively (both P<0.001). Cox proportional hazard models adjusted for clinical backgrounds showed that, as compared with G2, both G1 and G4 had increased risk for all-cause death, HF hospitalization and a composite of all-cause death, and HF hospitalization, indicating the J-curve relationship between serum UA levels and prognosis (Figure).

Prognostic impacts of serum UA levels

Conclusions

Both decreased and increased UA levels were associated with increased incidence of death and HF hospitalization in HF patients.

Importance of prognostic stratification via gene mutation analysis in elderly patients with acute myelogenous leukemia

INTRODUCTION

Acute myelogenous leukemia (AML) in elderly patients is associated with an increased incidence of complications and treatment-related toxicity because of the frequency of comorbid disease and age-related deterioration in organ function. Despite advances in AML treatment in recent years, elderly patients have experienced limited benefit, and their outcomes remain poor. This study aimed to perform a comprehensive gene mutation analysis in elderly AML patients and identify gene mutations that could serve as prognostic factors.

METHODS

An analysis of gene mutations was performed for 281 AML patients, including 98 elderly patients aged 65 years or above.

RESULTS

Compared to younger AML patients, elderly patients showed a higher frequency of the following gene mutations: TP53 (P = 0.026), PTPN11 (P = 0.006), RUNX1 (P = 0.024), TET2 (P = 0.002), and ASXL1 (P = 0.023). The complete remission rate was significantly lower in DNMT3A mutation-positive cases (4.26%, P = 0.011) and TP53 mutation-positive cases (2.13%, P = 0.031) than in negative cases. The overall survival rate was significantly poorer in cases with FLT3-ITD (P = 0.003), DNMT3A (P = 0.033), or TP53 mutation (P < 0.001). Conversely, cases with PTPN11 mutation (P = 0.014) had a significantly more favorable prognosis. In multivariate analysis, FLT3-ITD (P = 0.011) and TP53 mutation positivity (P = 0.002) were independent poor prognostic factors, as were a performance status of 3 or above (P < 0.001) and poor cytogenetic prognosis (P = 0.001). In contrast, PTPN11 mutation positivity (P = 0.023) was an independent favorable prognosis factor.

CONCLUSION

Analysis of gene mutations in elderly AML patients is very important, not only for establishing prognosis, but also for introducing appropriate molecular-targeted treatments.

Abstract WP524: Outcomes With Rivaroxaban in Patients With Nonvalvular Atrial Fibrillation and Worsening Renal Function

Introduction: Direct oral anticoagulants are widely used in patients with nonvalvular atrial fibrillation (AF) to reduce the risk of stroke and systemic embolism, however, there is not enough real-world data of their effectiveness and safety in patients with worsening renal function (WRF). Xarelto post-authorization safety and effectiveness study in Japanese patients with atrial fibrillation (XAPASS) is a prospective observational post-marketing surveillance study mandated by the Japanese authority. It aims to examine safety and effectiveness of rivaroxaban in everyday clinical practice. This analysis investigated one year outcomes among patients with WRF and stable renal function (SRF) in XAPASS.

Methods: One year follow-up data of 9578 patients enrolled in XAPASS were analyzed to evaluate baseline characteristics and safety/effectiveness profile among patients with WRF and SRF. WRF was defined as a decrease of more than 20% from enrollment creatinine clearance measurement at any time point during the study. SRF was defined as the absence of WRF at any time.

Results: We identified 1229 patients (12.8%) with WRF and 6280 patients (65.6%) with SRF among 9578 patients. WRF patients were significantly older, and had significantly higher mean CHA 2 DS 2 -VASc score and modified HAS-BLED score compared to SRF patients. Prevalence of hypertension, congestive heart failure, ischemic stroke/transient ischemic attack, and myocardial infarction was higher in WRF patients. There was no difference in rates of major bleeding (hazard ratio (HR) 1.20; 95% confidence interval (CI) 0.75-1.90; p=0.45) or the composite endpoint of stroke, systemic embolism or myocardial infarction (HR 1.06; 95% CI 0.65-1.71; p=0.82) between patients with WRF and SRF. WRF patients experienced a higher incidence of transfusion of 2 units or more (0.46 versus 0.14 events per 100 patient-years; HR 3.19; 95% CI 1.04-9.74; p=0.03) versus SRF patients. Rates of other major bleeding subgroups defined according to ISTH criteria were similar between patients with WRF and SRF.

Conclusions: WRF during rivaroxaban treatment did not significantly increase the rates of major bleeding or thromboembolic events, although it was associated with a higher incidence of transfusion of 2 units or more.

Abstract WP528: Safety and Effectiveness of Rivaroxaban Among Japanese Elderly Patients With Nonvalvular Atrial Fibrillation in Everyday Clinical Practice

Introduction: Nonvalvular atrial fibrillation (AF) is common in elderly patients, who face increased risk of thromboembolism and bleeding during antithrombotic therapy. Xarelto post-authorization safety & effectiveness study in Japanese patients with atrial fibrillation (XAPASS) is a prospective observational post-marketing surveillance study mandated by the Japanese authority. It aims to examine safety and effectiveness of rivaroxaban in everyday clinical practice. This analysis evaluated one-year outcomes and patient characteristics associated with major bleeding or thromboembolic events among elderly patients enrolled in XAPASS.

Methods: A total of 11,308 patients with AF newly starting rivaroxaban were enrolled between April 2012 and June 2014. As of September 2017, one year follow-up data were collected from 9578 patients, and 4685 patients (48.9%) were aged ≥75 years.

Results: Patients aged ≥75 years had higher rates of major bleeding (2.22 versus 1.35 events per 100 patient-years; p=0.004), and the composite endpoint of stroke, systemic embolism or myocardial infarction (2.41 versus 1.21 events per 100 patient-years; p<0.0001) compared with those aged <75 years. Rates of intracranial hemorrhage were less than 1% in both patient groups aged ≥75 years and <75 years (0.85 versus 0.59 events per 100 patient-years). There was no significant difference in major bleeding or thromboembolism among patients in age groups of 75-79, 80-84, and ≥85 years. Multivariate analysis identified hepatic impairment and concomitant use of acetylsalicylic acid as risk factors of major bleeding events in patients aged ≥75 years (p=0.041 and p<0.0001, respectively). History of stroke was identified as a risk factor of thromboembolic events in the same patient group (p<0.0001).

Conclusions: Although elderly patients had higher rates of bleeding and thromboembolic events than younger patients, no significant difference was found in the outcomes between age groups of 75-79, 80-84, and ≥85 years. Benefit and risk of antithrombotic therapy should be thoroughly assessed in elderly patients. Additionally, elderly patients with risk factors of bleeding or thromboembolic events should be carefully monitored while taking anticoagulants.

Design and baseline characteristics of the Xarelto Post-Authorization Safety & Effectiveness Study in Japanese Patients with Atrial Fibrillation (XAPASS)

Background

The phase III Japanese Rivaroxaban Once‐Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (J‐ROCKET AF) showed that the rivaroxaban group had a lower event rate of intracranial bleeding than the warfarin group and that rivaroxaban was noninferior to warfarin for the principal safety outcome. However, safety and effectiveness data from unselected patients with AF in everyday clinical practice in Japan are lacking.

Methods

The Xarelto Post‐Authorization Safety & Effectiveness Study in Japanese Patients with Atrial Fibrillation (XAPASS) is a real‐world, prospective, single‐arm, observational study mandated by the Japanese authority as postmarketing surveillance. XAPASS involves patients with nonvalvular AF prescribed rivaroxaban. The principal safety outcome is a composite of major and nonmajor bleeding events, and the primary effectiveness outcome is the incidence of ischemic stroke, hemorrhagic stroke, noncentral nervous system systemic embolism, and myocardial infarction.

Results

In total, 11 308 patients were enrolled from April 2012 to June 2014. Their age was 73.1 ± 9.9 years, and their CHADS₂ score was 2.2 ± 1.3. Female patients, patients aged ≥75 years, patients with a body weight of ≤50 kg, and patients with a creatinine clearance of <50 mL/min constituted 38.1%, 48.7%, 19.5%, and 23.9% of all patients, respectively. Almost half (53.2%) of patients were prescribed other anticoagulants before starting rivaroxaban.

Conclusions

Data from this study will supplement those from the J‐ROCKET AF and provide practical information for the optimal use of rivaroxaban for stroke prevention in Japanese patients with AF (Clinicaltrials.gov: NCT01582737).

Ascorbic acid promotes cardiomyogenesis through SMAD1 signaling in differentiating mouse embryonic stem cells

Numerous groups have documented that Ascorbic Acid (AA) promotes cardiomyocyte differentiation from both mouse and human ESCs and iPSCs. AA is now considered indispensable for the routine production of hPSC-cardiomyocytes (CMs) using defined media; however, the mechanisms involved with the inductive process are poorly understood. Using a genetically modified mouse embryonic stem cell (mESC) line containing a dsRED transgene driven by the cardiac-restricted portion of the ncx1 promoter, we show that AA promoted differentiation of mESCs to CMs in a dose- and time-dependent manner. Treatment of mPSCs with AA did not modulate total SMAD content; however, the phosphorylated/active forms of SMAD2 and SMAD1/5/8 were significantly elevated. Co-administration of the SMAD2/3 activator Activin A with AA had no significant effect, but the addition of the nodal co-receptor TDGF1 (Cripto) antagonized AA’s cardiomyogenic-promoting ability. AA could also reverse some of the inhibitory effects on cardiomyogenesis of ALK/SMAD2 inhibition by SB431542, a TGFβ pathway inhibitor. Treatment with BMP2 and AA strongly amplified the positive cardiomyogenic effects of SMAD1/5/8 in a dose-dependent manner. AA could not, however, rescue dorsomorphin-mediated inhibition of ALK/SMAD1 activity. Using an inducible model system, we found that SMAD1, but not SMAD2, was essential for AA to promote the formation of TNNT2⁺-CMs. These data firmly demonstrate that BMP receptor-activated SMADs, preferential to TGFβ receptor-activated SMADs, are necessary to promote AA stimulated cardiomyogenesis. AA-enhanced cardiomyogenesis thus relies on the ability of AA to modulate the ratio of SMAD signaling among the TGFβ-superfamily receptor signaling pathways.

Generation of interspecies limited chimeric nephrons using a conditional nephron progenitor cell replacement system

Animal fetuses and embryos may have applications in the generation of human organs. Progenitor cells may be an appropriate cell source for regenerative organs because of their safety and availability. However, regenerative organs derived from exogenous lineage progenitors in developing animal fetuses have not yet been obtained. Here, we established a combination system through which donor cells could be precisely injected into the nephrogenic zone and native nephron progenitor cells (NPCs) could be eliminated in a time- and tissue-specific manner. We successfully achieved removal of Six2+ NPCs within the nephrogenic niche and complete replacement of transplanted NPCs with donor cells. These NPCs developed into mature glomeruli and renal tubules, and blood flow was observed following transplantation in vivo. Furthermore, this artificial nephron could be obtained using NPCs from different species. Thus, this technique enables in vivo differentiation from progenitor cells into nephrons, providing insights into nephrogenesis and organ regeneration.

The transplantation of tissue-specific progenitor cells may be an approach in organ regeneration. Here the authors show that the nephron progenitor population of a developing mouse kidney, when ablated, can be replaced by exogenously supplied rat nephron progenitors, generating interspecies nephrons.

Adult T-cell leukemia-lymphoma complicated by Takotsubo cardiomyopathy and HTLV-1-associated myelopathy after treatment with the anti-CCR4 antibody mogamulizumab

Adult T-cell leukemia-lymphoma (ATL) caused by human T-lymphotropic virus type 1 (HTLV-1) is generally associated with poor prognosis. The anti-CCR4 antibody mogamulizumab is one of the options for refractory or relapsed ATL. Mogamulizumab is intravenously administered as a single agent at a dose of 1.0 mg/kg once a week for 8 weeks. The overall response rate is reported to be 50%. Reported common adverse events after administration of mogamulizumab are leukocytopenia, infusion reaction, and skin rash. Although rare, mogamulizumab-associated cardiomyopathy has also been reported. HTLV-1 is also associated with a number of diseases, such as HTLV-1-associated myelopathy (HAM). Approximately 0.25% of infected individuals are estimated to develop HAM. HAM is an inflammatory disease of the central nervous system, which is characterized by slowly progressive spastic paresis of bilateral lower limbs and bladder-rectal disorder. Coexistence of ATL and HAM has rarely been reported. Here we present the case of a patient with ATL in whom Takotsubo cardiomyopathy and HAM developed after mogamulizumab administration.

Circulatory CNP Rescues Craniofacial Hypoplasia in Achondroplasia

Achondroplasia is the most common genetic form of human dwarfism, characterized by midfacial hypoplasia resulting in occlusal abnormality and foramen magnum stenosis, leading to serious neurologic complications and hydrocephalus. Currently, surgery is the only way to manage jaw deformity, neurologic complications, and hydrocephalus in patients with achondroplasia. We previously showed that C-type natriuretic peptide (CNP) is a potent stimulator of endochondral bone growth of long bones and vertebrae and is also a potent stimulator in the craniofacial region, which is crucial for midfacial skeletogenesis. In this study, we analyzed craniofacial morphology in a mouse model of achondroplasia, in which fibroblast growth factor receptor 3 (FGFR3) is specifically activated in cartilage ( Fgfr3^ach mice), and investigated the mechanisms of jaw deformities caused by this mutation. Furthermore, we analyzed the effect of CNP on the maxillofacial area in these animals. Fgfr3^ach mice exhibited midfacial hypoplasia, especially in the sagittal direction, caused by impaired endochondral ossification in craniofacial cartilage and by premature closure of the spheno-occipital synchondrosis, an important growth center in craniomaxillofacial skeletogenesis. We crossed Fgfr3^ach mice with transgenic mice in which CNP is expressed in the liver under the control of the human serum amyloid-P component promoter, resulting in elevated levels of circulatory CNP ( Fgfr3^ach/SAP-Nppc-Tg mice). In the progeny, midfacial hypoplasia in the sagittal direction observed in Fgfr3^ach mice was improved significantly by restoring the thickness of synchondrosis and promoting proliferation of chondrocytes in the craniofacial cartilage. In addition, the foramen magnum stenosis observed in Fgfr3^ach mice was significantly ameliorated in Fgfr3^ach/SAP-Nppc-Tg mice due to enhanced endochondral bone growth of the anterior intraoccipital synchondrosis. These results clearly demonstrate the therapeutic potential of CNP for treatment of midfacial hypoplasia and foramen magnum stenosis in achondroplasia.

The Therapeutic Outcomes of Mechanical Ventilation in Hematological Malignancy Patients with Respiratory Failure

Objective In hematological malignancy patients, the complication of acute respiratory failure often reaches a degree of severity that necessitates mechanical ventilation. The objective of the present study was to investigate the therapeutic outcomes of mechanical ventilation in hematological malignancy patients with respiratory failure and to analyze the factors that are associated with successful treatment in order to identify the issues that should be addressed in the future. Methods The present study was a retrospective analysis of 71 hematological malignancy patients with non-cardiogenic acute respiratory failure who were treated with mechanical ventilation at Nippon Medical School Hospital between 2003 and 2014. Results Twenty-six patients (36.6%) were treated with mechanical ventilation in an intensive care unit (ICU). Non-invasive positive pressure ventilation (NPPV) was applied in 29 cases (40.8%). The rate of successful mechanical ventilation treatment with NPPV alone was 13.8%. The rate of endotracheal extubation was 17.7%. A univariate analysis revealed that the following factors were associated with the successful extubation of patients who received invasive mechanical ventilation: respiratory management in an ICU (p=0.012); remission of the hematological disease (p=0.011); female gender (p=0.048); low levels of accompanying non-respiratory organ failure (p=0.041); and the non-use of extracorporeal circulation (p=0.005). A subsequent multivariate analysis revealed that respiratory management in an ICU was the only variable associated with successful extubation (p=0.030). Conclusion The outcomes of hematological malignancy patients who receive mechanical ventilation treatment for respiratory failure are very poor. Respiratory management in an ICU environment may be useful in improving the therapeutic outcomes of such patients.