Glasdegib with intensive/nonintensive chemotherapy in Japanese patients with untreated acute myeloid leukemia or high-risk myelodysplastic syndromes.

Glasdegib is a potent, selective, oral inhibitor of the hedgehog signaling pathway. In this phase I study, previously untreated Japanese patients with acute myeloid leukemia (AML) or high-risk myelodysplastic syndromes were treated with glasdegib (100 mg once daily) combinations: low-dose cytarabine (20 mg twice daily; cohort 1, n = 6; expansion cohort, n = 15); daunorubicin and cytarabine (60 mg/m2 i.v.; cohort 2, n = 6); or azacitidine (100 mg/m2 i.v.; cohort 3, n = 6). Patients, except cohort 2, were ineligible for intensive chemotherapy. The primary end-point was dose-limiting toxicity in cohorts 1-3 and disease-modifying response in the expansion cohort. Disease-modifying response rate was tested with the null hypothesis of 6.8%, which was set based on the results from the phase II BRIGHT AML 1003 study (NCT01546038). No dose-limiting toxicities were observed in cohorts 1 or 3; one patient in cohort 2 experienced a dose-limiting toxicity of grade 3 erythroderma. The most common grade ≥3 treatment-related adverse events were neutropenia and thrombocytopenia (66.7% each) in cohort 1 and thrombocytopenia (60.0%) in the expansion cohort. In the expansion cohort, the disease-modifying response rate was 46.7% (90% confidence interval, 24.4-70.0; p < 0.0001), with all patients achieving either a complete response or complete response with incomplete blood count recovery. Median overall survival was 13.9 months. In this study, the primary disease-modifying response end-point with glasdegib plus low-dose cytarabine was met. The study confirms the safety and efficacy of glasdegib plus low-dose cytarabine in Japanese patients with AML ineligible for intensive chemotherapy.

Antibody response after third dose of COVID-19 mRNA vaccination in allogeneic hematopoietic stem cell transplant recipients is comparable to that in healthy counterparts.

To determine the efficacy of SARS-CoV-2 mRNA vaccination for allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients, we measured antibody titer serially in 92 allo-HSCT patients. Among the evaluable 87 patients, median age at vaccination was 53 years (range, 18-75). The average time between allo-HSCT and vaccination was 3.3 years (range, 0.5-15.7). One month after the second dose, 70 patients (80.5%) had a positive response, whereas 17 patients (19.5%) had a negative response (< 20 U/mL). Only patients older than 44 years had a negative response. Low IgM level was the only significant predictor of vaccine failure in elderly patients. When antibody response before and after the third vaccination was examined in 47 patients, antibodies increased significantly from a median of 18.3 U/mL to 312.6 U/mL (P < 0.01). The median antibody titer after the third vaccination of healthy individuals (n = 203) was 426.4 U/mL, which was comparable to that of patients (P = 0.2). The antibody titer after the third mRNA vaccination increased even in patients whose first two mRNA vaccinations failed. These findings suggest that allo-HSCT recipients should receive the mRNA vaccine regularly.

Autologous peripheral blood stem cell transplantation for Philadelphia chromosome-positive acute lymphoblastic leukemia is safe but poses challenges for long-term maintenance of molecular remission: Results of the Auto-Ph17 study.

Autologous hematopoietic stem cell transplantation (SCT) is not a standard treatment option for Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL); however, its position has been reassessed since the introduction of tyrosine kinase inhibitors (TKIs). We prospectively analyzed the efficacy and safety of autologous peripheral blood SCT (auto-PBSCT) for Ph+ALL patients aged between 55 and 70 years who had achieved complete molecular remission. Melphalan, cyclophosphamide, etoposide, and dexamethasone were used for conditioning. A total of 12 courses of maintenance therapy, including dasatinib, were performed. The required number of CD34+ cells was harvested in all five patients. No patient died within 100 days after auto-PBSCT, and no unexpected serious adverse events were observed. Although 1-year event-free survival was 100%, hematological relapse was observed in three patients at a median of 801 days (range, 389-1088 days) after auto-PBSCT. Molecular progressive disease was observed in the other two patients, although they maintained their first hematological remission at the last visit. Auto-PBSCT can be safely performed for Ph+ALL with TKIs. A limitation of auto-PBSCT was suggested, despite the increase in the intensity of a single treatment. The development of long-term therapeutic strategies by including new molecular targeted drugs is warranted to maintain long-term molecular remission.

Clinical utility of genomic profiling of AML using paraffin-embedded bone marrow clots: HM-SCREEN-Japan 01.

Next-generation sequencing of AML has identified specific genetic mutations in AML patients. Hematologic Malignancies (HM)-SCREEN-Japan 01 is a multicenter study to detect actionable mutations using paraffin-embedded bone marrow (BM) clot specimens rather than BM fluid in AML patients for whom standard treatment has not been established. The purpose of this study is to evaluate the presence of potentially therapeutic target gene mutations in patients with newly diagnosed unfit AML and relapsed/refractory AML (R/R-AML) using BM clot specimens. In this study, 188 patients were enrolled and targeted sequencing was undertaken on DNA from 437 genes and RNA from 265 genes. High-quality DNA and RNA were obtained using BM clot specimens, with genetic alterations successfully detected in 177 patients (97.3%), and fusion transcripts in 41 patients (23.2%). The median turnaround time was 13 days. In the detection of fusion genes, not only common fusion products such as RUNX1-RUX1T1 and KMT2A rearrangements, but also NUP98 rearrangements and rare fusion genes were observed. Among 177 patients (72 with unfit AML, 105 with R/R-AML), mutations in KIT and WT1 were independent factors for overall survival (hazard ratio = 12.6 and 8.88, respectively), and patients with high variant allele frequency (≥40%) of TP53 mutations had a poor prognosis. As for the detection of actionable mutations, 38% (n = 69) of patients had useful genetic mutation (FLT3-ITD/TKD, IDH1/2, and DNMT3AR822 ) for treatment selection. Comprehensive genomic profiling using paraffin-embedded BM clot specimens successfully identified leukemic-associated genes that can be used as therapeutic targets.

Mutated KIT Tyrosine Kinase as a Novel Molecular Target in Acute Myeloid Leukemia.

KIT is a type-III receptor tyrosine kinase that contributes to cell signaling in various cells. Since KIT is activated by overexpression or mutation and plays an important role in the development of some cancers, such as gastrointestinal stromal tumors and mast cell disease, molecular therapies targeting KIT mutations are being developed. In acute myeloid leukemia (AML), genome profiling via next-generation sequencing has shown that several genes that are mutated in patients with AML impact patients' prognosis. Moreover, it was suggested that precision-medicine-based treatment using genomic data will improve treatment outcomes for AML patients. This paper presents (1) previous studies regarding the role of KIT mutations in AML, (2) the data in AML with KIT mutations from the HM-SCREEN-Japan-01 study, a genome profiling study for patients newly diagnosed with AML who are unsuitable for the standard first-line treatment (unfit) or have relapsed/refractory AML, and (3) new therapies targeting KIT mutations, such as tyrosine kinase inhibitors and heat shock protein 90 inhibitors. In this era when genome profiling via next-generation sequencing is becoming more common, KIT mutations are attractive novel molecular targets in AML.

Comparison of clonal architecture between primary and immunodeficient mouse-engrafted acute myeloid leukemia cells.

Patient-derived xenografts (PDX) are widely used as human cancer models. Previous studies demonstrated clonal discordance between PDX and primary cells. However, in acute myeloid leukemia (AML)-PDX models, the significance of the clonal dynamics occurring in PDX remains unclear. By evaluating changes in the variant allele frequencies (VAF) of somatic mutations in serial samples of paired primary AML and their PDX bone marrow cells, we identify the skewing engraftment of relapsed or refractory (R/R) AML clones in 57% of PDX models generated from multiclonal AML cells at diagnosis, even if R/R clones are minor at <5% of VAF in patients. The event-free survival rate of patients whose AML cells successfully engraft in PDX models is consistently lower than that of patients with engraftment failure. We herein demonstrate that primary AML cells including potentially chemotherapy-resistant clones dominantly engraft in AML-PDX models and they enrich pre-existing treatment-resistant subclones.

Assessment of cellular response to mitogens in long-term allogeneic hematopoietic stem cell transplantation survivors.

Infection is one of the major causes of death in hematopoietic stem cell transplantation (HSCT) survivors. Precise assessments of immune function after HSCT will be critical in establishing appropriate treatment and prophylaxis, such as re-vaccination. Although several surrogate markers for prediction of clinical outcomes after HSCT have been proposed, definitive markers of immune reconstitution and data on those markers in long-term survivors are lacking. In this study, cellular response to mitogens was assessed and clinical features associated with a poor response to mitogens were investigated in long-term allogeneic HSCT survivors. Age at transplantation and age at the time of mitogen stimulation test were each identified as significant risk factors for poor response to phytohemagglutinin and concanavalin A, respectively (P < 0.001 each). However, time elapsed since transplantation was not found to be correlated with responsiveness to mitogens in this study. Prospective, in-depth studies on immune reconstitution are needed to establish appropriate prophylaxis against infections after HSCT and a schedule for re-vaccination.

Comparison of Transplantation Outcomes after Foscarnet and Ganciclovir Administration as First-Line Anti-Cytomegalovirus Preemptive Therapy.

Ganciclovir (GCV) and foscarnet (FCN) are effective anti-cytomegalovirus (CMV) preemptive therapies; however, the impact of the 2 agents on various clinical outcomes of allogeneic hematopoietic stem cell transplantation (HSCT) remains unclear. We retrospectively analyzed data on 532 patients undergoing allogeneic HSCT from unrelated donors and administered FCN (n = 86) or GCV (n = 446) as first-line anti-CMV preemptive therapy. Overall survival, relapse, and nonrelapse mortality (NRM) did not differ between the FCN and GCV groups, whereas the GCV group had a higher risk of chronic graft-versus-host disease (cGVHD) (hazard ratio [HR], 2.38; 95% confidence interval [CI], 1.28 to 4.39; P = .006) and extensive cGVHD (HR, 3.94; 95% CI, 1.43 to 10.9; P = .008). All 13 patients with cGVHD in the FCN group survived. Switching to the other agent was done mainly due to hematologic adverse events in the GCV group and mainly due to insufficient efficacy in the FCN group. The incidence of end-organ CMV disease was similar in the 2 groups. Selection of FCN or GCV as first-line preemptive anti-CMV therapy did not affect survival, relapse, or NRM. Physicians can select either of the agents, depending on the clinical situation; however, the selection may influence the cGVHD-related clinical course in HSCT recipients.

[Bacillus cereus bacteremia in patients with hematological disorders].

Bacillus cereus bacteremia is an infectious disease that may sometimes be fatal with a rapid clinical course. We performed a retrospective analysis on 12 patients with Bacillus cereus bacteremia recruited from January 2010 to March 2015. The primary diseases were acute leukemia (n=5), myelodysplastic syndromes (n=3), malignant lymphoma (n=3), and hemophagocytic syndrome (n=1). Neutrophil count at the onset of this bacteremia was less than 500 cells/µl in 9 patients. At the onset of bacteremia, we observed neurological symptoms (n=7), gastrointestinal symptoms (n=6), and findings suspected of infection at the venous catheter insertion site (n=6). Vancomycin was administered to all the patients; 10 patients showed improvement whereas 2 died early after allogeneic hematopoietic stem cell transplantation owing to bacteremia. Three patients had sequelae of central nervous system disorders. Neurological and gastrointestinal symptoms with fever may be predictors for this bacteremia, and early administration of appropriate antibacterial drugs may improve the prognosis. Future research should be aimed toward the identification of the clinical features of poor prognosis and establishment of remedies for Bacillus cereus bacteremia.

[Leukemic pulmonary infiltration diagnosed by sputum Giemsa-staining].

A 54-year-old man with acute myeloid leukemia (AML) underwent allogeneic bone marrow transplantation from a human leukocyte antigen-matched unrelated donor in nonremission status. Bone marrow aspiration performed on day 14 showed that the patient had achieved complete remission; however, he relapsed on day 28. The patient developed a wet cough, and chest computed tomography performed on day 27 revealed pneumonia. Because pneumonia developed along with the leukemic relapse, we suspected that it was due to pulmonary leukemic infiltration (PLI). Giemsa-stained sputum showed some blast cells and fluorescence in situ hybridization indicated that the patient had monosomy 7, which was also detected in bone marrow blasts. Though we prescribed hydroxycarbamide and decreased tacrolimus rapidly, AML progressed and led to the patient's death on day 45. Histopathological findings of the autopsy performed the next day showed diffuse alveolar damage in both lungs. The blast cells were packed in blood vessels of alveolar septa and were also seen in alveoli. PLI was diagnosed pathologically. In conclusion, our case demonstrates that Giemsa stain of sputum is useful in quick diagnosis of PLI without invasive examination.

Day 0 bone marrow pathology of allogeneic hematopoietic stem cell transplantation is a novel prognostic factor in myeloid malignancies.

Residual disease (RD) is one of the risk factors for relapse after hematopoietic stem cell transplantation (HSCT) in hematological malignancies. Although recent advances in the technology for detecting minimal/measurable RD, such as multiparameter flow cytometry and quantitative PCR, enable risk stratifications of disease relapse, these examinations still have limitations in routine clinical practice. In this study, we assessed RD in bone marrow (BM) specimens on day 0 of allogeneic HSCT by immunostaining of case-specific leukemic blast markers and analyzed the relationship between day 0 BM status and HSCT outcomes. We analyzed 82 adult HSCT recipients with myeloid malignancies. BM histology of day 0 revealed almost empty marrow with a small number of residual BM cells. However, residual blasts could be detected by immunostaining even for only a few cells. When patients were divided into two groups according to the existence of RD on day 0, those with positive RD showed significantly lower overall survival rate (27% vs. 73%, P<0.001) and higher cumulative incidence of relapse (46% vs. 9%, P=0.006) at one year compared to those with negative RD. Furthermore, even if they were not in remission at the point of the pre-conditioning evaluation, the patients who achieved negative RD on day 0 showed comparable prognosis with those who maintained remission before conditioning. This study shows the efficacy of day 0 BM pathology of allogeneic HSCT as a prognostic factor that can contribute to clinical decisions on post-transplant strategies.

The stability of initial tacrolimus concentration following allogeneic hematopoietic stem cell transplantation reduces the risk of acute GVHD.

BACKGROUND: Early tacrolimus (TAC) concentrations correlate with the risk of acute graft-versus-host disease (aGVHD); however, whether the variability of early TAC concentrations after allo-HSCT governs the occurrence of aGVHD remains unknown. Here, we evaluate the correlation between the intrapatient variability (IPV) of initial TAC concentrations and the development of aGVHD. METHODS: We retrospectively assessed 202 patients who underwent allo-HSCT and received standard GVHD prophylaxis by continuous intravenous (iv) infusion of TAC and iv methotrexate. IPV was calculated by using the % coefficient of variation in the initial 4 weeks. RESULTS: With median follow-up duration of 20.7 months, 24 patients were diagnosed with grades II-IV aGVHD. Overall survival (OS) and relapse at 12 months after allo-HSCT were 70.6% (95% confidence interval [CI], 63.7%-76.4%) and 18.9% (95% CI, 13.0%-24.4%), respectively. When IPV was categorized into two groups (high: ≥9.5%; low: <9.5%), the cumulative incidence of grades II-IV aGVHD was greater in the IPV-high group at week 3 (odds ratio: 4.15; 95% CI, 1.37%-12.6%, P = .01). No significant differences were observed in OS and relapse between the two groups. CONCLUSION: We concluded that adjusting early TAC concentration stable may reduce aGVHD after allo-HSCT without affecting the relapse rate.

Targeting MEF2D-fusion Oncogenic Transcriptional Circuitries in B-cell Precursor Acute Lymphoblastic Leukemia.

The cellular context that integrates gene expression, signaling, and metabolism dictates the oncogenic behavior and shapes the treatment responses in distinct cancer types. Although chimeric fusion proteins involving transcription factors (TF) are hallmarks of many types of acute lymphoblastic leukemia (ALL), therapeutically targeting the fusion proteins is a challenge. In this work, we characterize the core regulatory circuitry (CRC; interconnected autoregulatory loops of TFs) of B-ALL involving MEF2D-fusions and identify MEF2D-fusion and SREBF1 TFs as crucial CRC components. By gene silencing and pharmacologic perturbation, we reveal that the CRC integrates the pre-B-cell receptor (BCR) and lipid metabolism to maintain itself and govern malignant phenotypes. Small-molecule inhibitors of pre-BCR signaling and lipid biosynthesis disrupt the CRC and silence the MEF2D fusion in cell culture and show therapeutic efficacy in xenografted mice. Therefore, pharmacologic disruption of CRC presents a potential therapeutic strategy to target fusion protein-driven leukemia. SIGNIFICANCE: Cancer type-specific gene expression is governed by transcription factors involved in a highly interconnected autoregulatory loop called CRC. Here, we characterized fusion protein-driven CRC and identified its pharmacologic vulnerabilities, opening therapeutic avenues to indirectly target fusion-driven leukemia by disrupting its CRC.See related commentary by Sadras and Müschen, p. 18. This article is highlighted in the In This Issue feature, p. 5.

Prediction of clinical outcome by controlling nutritional status (CONUT) before allogeneic hematopoietic stem cell transplantation in myeloid malignancies.

Malnutrition before allogeneic hematopoietic cell transplantation (allo-HCT) is associated with poor clinical outcomes. Herein, we evaluated the predictive value of controlling nutritional status (CONUT) in patients undergoing allo-HCT for myeloid malignancies. We retrospectively analyzed 200 patients with myeloid malignancies who underwent allo-HCT for the first time. We evaluated CONUT before the initiation of conditioning and compared malnourished patients (poor CONUT, n = 56) with non-malnourished patients (normal CONUT, n = 144). The cumulative incidence of non-relapse mortality within 100 days (early NRM) was significantly higher in the poor CONUT group than in the normal CONUT group [21.4% (95% CI: 11.8-33.0%) vs. 9.7% (95% CI: 5.6-15.2%); P = 0.025]. In multivariate analysis, poor CONUT was an independent and significant risk factor for early NRM [HR: 2.2 (95% CI: 1.0-4.7); P = 0.048]. The overall 1-year survival rate was significantly lower in the poor CONUT group than in the normal CONUT group [53.3% (95% CI: 39.4-65.4%) vs. 71.0% (95% CI: 62.7-77.7%); P = 0.005]. These findings suggest that CONUT before allo-HCT is a useful predictor of poor outcomes in patients with myeloid malignancies.

ZNF384-fusion proteins have high affinity for the transcriptional coactivator EP300 and aberrant transcriptional activities.

Zinc-finger protein 384 (ZNF384) fusion (Z-fusion) genes have recently been identified as recurrent fusion genes in B-cell precursor acute lymphoblastic leukaemia (BCP-ALL) and have been detected in 7-17% of Philadelphia chromosome-negative BCP-ALL cases. We selected SALL4 and ID2 as potential Z-fusion-specific transcriptional targets that might lead to the differentiation disorder of Z-fusion-positive ALL. The introduction of EP300-ZNF384 and SYNRG-ZNF384 induced the expression of these genes. Z-fusion proteins exhibited stronger transcriptional activities on the promoter or enhancer region of these genes than Wild-Z. Furthermore, GST pull-down assay revealed that Z-fusion proteins associated more strongly with EP300 than Wild-Z. Coexpression of EP300 specifically enhanced the transcriptional activities of Z-fusion proteins. We propose the increased EP300 binding of Z-fusion proteins as a mechanism for their increased transcriptional activities.

Correction to: Thalidomide maintenance therapy in Japanese myeloma patients: a multicenter, phase II clinical trial (COMET study).

The authors would like to correct the errors in the publication of the original article. The correction details are given below.

Thalidomide maintenance therapy in Japanese myeloma patients: a multicenter, phase II clinical trial (COMET study).

A prospective, multicenter, phase II study was performed to assess the efficacy and safety of thalidomide maintenance therapy at different doses in Japanese multiple myeloma (MM) patients. This study included 34 patients (median age, 74 years) who were previously treated with not more than three prior therapies and whose response status was evaluated as at least stable disease. They were randomized into Group A (no maintenance; 12 patients), Group B (50 mg thalidomide maintenance; 12 patients), and Group C (100 mg thalidomide maintenance; 10 patients), respectively. Thalidomide maintenance therapy resulted in improved depth of response in three cases (13.6%) and sustained response after induction therapy in eight cases (36.4%). Two-year progression-free survival (PFS) was 25.0%, 33.3%, and 77.8% in Groups A, B, and C, respectively, and was significantly higher in Group C than in Group A (p = 0.005). There was no difference in the incidence of hematological or non-hematological adverse events between Groups B and C. The current study demonstrates that maintenance with daily thalidomide at 100 mg, but not 50 mg, improved depth of response and prolonged PFS, and that this treatment was feasible for use in Japanese MM patients.

Chromosomal translocation-mediated evasion from miRNA induces strong MEF2D fusion protein expression, causing inhibition of PAX5 transcriptional activity.

MEF2D fusion genes are newly discovered recurrent gene abnormalities that are detected in approximately 5% of acute lymphoblastic leukemia cases. We previously demonstrated that the vector-driven expression of MEF2D fusion proteins was markedly stronger than that of wild-type MEF2D; however, the underlying mechanisms and significance of this expression have yet to be clarified. We herein showed that the strong expression of MEF2D fusion proteins was caused by the loss of the target site of miRNA due to gene translocation. We identified the target region of miRNA located in the coding region and selected miR-122 as a candidate of the responsible miRNA. Mutations at a putative binding site of miR-122 increased MEF2D expression, while the transfection of its miRNA mimic reduced the expression of wild-type MEF2D, but not MEF2D fusion proteins. We also found that MEF2D fusion proteins inhibited the transcriptional activity of PAX5, a B-cell differentiation regulator in a manner that depended on fusion-specific strong expression and an association with histone deacetylase 4, which may lead to the differentiation disorders of B cells. Our results provide novel insights into the mechanisms underlying leukemia development by MEF2D fusion genes and the involvement of the deregulation of miRNA-mediated repression in cancer development.