Impact of BK polyomavirus viremia on the outcomes of allogeneic hematopoietic stem cell transplantation.

Although it is known that BK polyomavirus (BKPyV) causes hemorrhagic cystitis (HC) after allogeneic hematopoietic stem cell transplantation (HSCT), the clinical significance of BKPyV viremia has not been fully evaluated. We retrospectively analyzed the results of quantitative polymerase chain reaction (PCR) evaluations for detecting BKPyV in the whole blood samples of patients undergoing allogeneic HSCT during the period from January 2010 to June 2020 at a single institute, Tokyo Medical and Dental University. BKPyV was detected in the blood of 28 of the 107 evaluated patients, and the cumulative incidence of was 27.9% (95%CI: 20.2-37.9%). HC due to BKPyV developed in four of the 28 patients with BKPyV viremia (14.3%) and in two of the 79 patients without it (2.5%; P < 0.05). BKPyV viremia itself did not affect the patients' post-transplant estimated glomerular filtration rate (eGFR), but BKPyV viremia with a high viral load was significantly associated with decreased eGFR values (P < 0.05). BKPyV viremia was also associated with significantly lower progression-free survival at 3 years (35.1% [95%CI: 17.8-53.1%] vs. 60.4% [95%CI: 48.4-70.5], P < 0.05). Our findings demonstrated that BKPyV viremia was associated with onset of HC, an early decline of renal function, and poorer survival after allogeneic HSCT. Further studies are needed to test these results and elucidate the mechanisms of renal dysfunction associated with BKPyV viremia.

Clinical factors for central nervous system progression and survival in primary vitreoretinal lymphoma.

Primary vitreoretinal lymphoma (PVRL) is a rare subtype of malignant lymphoma with a poor prognosis because of high frequency of central nervous system (CNS) progression. Identification of factors associated with CNS progression is essential to improve the prognosis of patients with PVRL. We conducted a retrospective study of 54 patients diagnosed with PVRL and treated at our hospital to identify factors associated with CNS progression and prognosis. All patients were treated with intravitreal methotrexate (MTX) injections in the affected eyes until lesion resolution. Twenty-four patients were treated with systemic administration of high-dose MTX (systemic HD-MTX) every other week for a total of five cycles following intravitreal MTX injection. Of 24 patients, 20 completed five cycles of systemic HD-MTX. The 5-year cumulative incidence of CNS progression and overall survival (OS) rate were 78.0% and 69.0% respectively. By univariate and multivariate analyses, bilateral disease and the detection of B-cell clonality confirmed by flow cytometric analysis were risk factors associated with CNS progression. Moreover, systemic HD-MTX completion reduced the risk of CNS progression and was identified as a factor affecting OS. In this study, factors for CNS progression identified may potentially contribute to the optimized therapeutic stratification to improve the survival of patients with PVRL.

[Acute promyelocytic leukemia with asymptomatic cerebral hemorrhage].

A 43-year-old man presenting with oral bleeding was diagnosed with acute promyelocytic leukemia (APL). Induction chemotherapy consisting of all-trans retinoic acid and idarubicin was initiated, and disseminated intravascular coagulation (DIC) was treated with fresh frozen plasma and recombinant thrombomodulin infusions. The patient was free from neurological symptoms throughout the clinical course. However, cerebral hemorrhagic lesions were detected incidentally on magnetic resonance imaging performed to screen for leukemic central nervous system invasion at 2 weeks after treatment initiation. Imaging findings suggested subacute or later-phase cerebral hemorrhage. Platelet transfusions and other supportive care was provided. Serial imaging evaluations confirmed reduction of the hemorrhagic lesions. Hematological remission was achieved after induction chemotherapy, and no symptoms due to cerebral hemorrhage developed during the subsequent consolidation therapy. As patients with APL characteristically experience hemorrhagic events due to bleeding tendency caused by DIC, physicians should be aware of the possibility of asymptomatic cerebral hemorrhage in these patients.

[Manufacturing results of tisagenlecleucel for acute lymphoblastic leukemia: a survey by the CAR-T cell therapy taskforce of the Japan Society of Transfusion Medicine and Cell Therapy].

The frequency of the manufacturing failure of chimeric antigen receptor (CAR)-T cell therapy in clinical practice is unknown. To clarify the current state of how likely CAR-T cell production is to succeed or fail for B-cell acute lymphoblastic leukemia (B-ALL), we analyzed cases in which the production of tisagenlecleucel was performed for patients with B-ALL at 15 facilities in Japan from October 2019 to March 2022. Total 81 patients (47 males and 34 females) were analyzed. The median age at apheresis was 13 years (1-25) with a median number of prior treatments of 4 (1-9). The numbers of patients with histories of allogeneic transplantation, inotuzumab ozogamicin, or blinatumomab treatments were 51 (63.0%), 26 (32.1%), and 37 (45.7%), respectively. The median blast percentage and CD3+ cell counts in peripheral blood were 0% (0-91.5), and 611/µl (35-4,210) at apheresis, and the median number of CD3+ cells shipped was 2.2×109 (0.5-8.3). While cases with a history of heavy prior treatment before apheresis were included, no manufacturing failures were observed. Continuing to monitor the status of manufacturing failures is necessary as the number of B-ALL cases treated with CAR-T cell therapy increases.

Lymphoproliferative disorder risk after methotrexate treatment for rheumatoid arthritis.

Methotrexate (MTX)-associated lymphoproliferative disorder (MTX-LPD) is a troublesome problem in patients receiving MTX for rheumatoid arthritis (RA). However, its incidence, prognosis, and risk factors remain unclear. In this retrospective study, we evaluated the actual incidence, prognostic impact, and risk factors of MTX-LPD. Of the 986 patients with RA treated with MTX, 90 patients experienced 95 new malignancies (NMs), with LPD as the most frequent in 26 patients. The cumulative LPD incidences were 1.3% and 4.7% at 5 and 10 years after MTX initiation, respectively. Among the 24 patients who discontinued MTX after developing LPD, 15 showed sustained regression, without difference in overall survival between patients with LPD and without NM. Inflammatory markers and absolute lymphocyte counts were not useful for early LPD development detection, but most of the patients with LPD had persistently elevated erythrocyte sedimentation ratios. Regarding concomitant drugs, tacrolimus increased the risk only if patients were not receiving biological disease-modifying antirheumatic drugs (bDMARDs). bDMARDs did not increase the risk for any of the drugs or the number of classes used. The number of LPD cases was lower in patients with IL-6A even after a long period after MTX, although with no statistically significant difference. Thus, approximately 1 in 20 patients with RA developed MTX-LPD over the 10 years of MTX treatment, but it did not affect the survival of patients with RA. Tacrolimus increased the risk of developing LPD for certain patients and should be used with caution.

Successful treatment of DOCK8 deficiency by allogeneic hematopoietic cell transplantation from alternative donors.

Dedicator of cytokinesis 8 (DOCK8) deficiency is a rare autosomal recessive inborn error of immunity (IEI) characterized by eczematous dermatitis, elevated serum IgE, and recurrent infections, comprising a seemingly hyper-IgE syndrome (HIES). DOCK8 deficiency is only curable with allogeneic hematopoietic cell transplantation (HCT), but the outcome of HCT from alternative donors is not fully understood. Here, we describe the cases of two Japanese patients with DOCK8 deficiency who were successfully treated by allogeneic HCT from alternative donors. Patient 1 underwent cord blood transplantation at the age of 16 years, and Patient 2 underwent haploidentical peripheral blood stem cell transplantation with post-transplant cyclophosphamide at the age of 22 years. Each patient received a fludarabine-based conditioning regimen. Their clinical manifestations, including refractory molluscum contagiosum, promptly improved post-HCT. They achieved successful engraftment and immune reconstitution without serious complications. Alternative donor sources such as cord blood and haploidentical donors can be options for allogeneic HCT for DOCK8 deficiency.

Risk factors for CAR-T cell manufacturing failure among DLBCL patients: A nationwide survey in Japan.

For successful chimeric antigen receptor T (CAR-T) cell therapy, CAR-T cells must be manufactured without failure caused by suboptimal expansion. In order to determine risk factors for CAR-T cell manufacturing failure, we performed a nationwide cohort study in Japan and analysed patients with diffuse large B-cell lymphoma (DLBCL) who underwent tisagenlecleucel production. We compared clinical factors between 30 cases that failed (7.4%) with those that succeeded (n = 378). Among the failures, the proportion of patients previously treated with bendamustine (43.3% vs. 14.8%; p < 0.001) was significantly higher, and their platelet counts (12.0 vs. 17.0 × 104 /µL; p = 0.01) and CD4/CD8 T-cell ratio (0.30 vs. 0.56; p < 0.01) in peripheral blood at apheresis were significantly lower than in the successful group. Multivariate analysis revealed that repeated bendamustine use with short washout periods prior to apheresis (odds ratio [OR], 5.52; p = 0.013 for ≥6 cycles with washout period of 3-24 months; OR, 57.09; p = 0.005 for ≥3 cycles with washout period of <3 months), low platelet counts (OR, 0.495 per 105 /µL; p = 0.022) or low CD4/CD8 ratios (

Dose optimization of tyrosine kinase inhibitor therapy in chronic myeloid leukemia.

The therapeutic outcomes of chronic myeloid leukemia (CML) have improved dramatically since tyrosine kinase inhibitors (TKIs) became available in clinical practice. Life expectancy of patients with CML is now close to that of the general population. Patients with CML who achieve sustained deep molecular response may discontinue TKI therapy. However, most patients still require TKI therapy for long periods without sustained deep molecular response. Given the awareness of increased incidence of arterial occlusive events in patients on TKI therapy, the optimal TKI selection should be based on age, comorbidities, risk classification, and goals of treatment. Dose optimization of TKI therapy reduces the incidence of adverse events while maintaining efficacy in CML.

[Perioperative management of laparoscopic cholecystectomy in a patient with paroxysmal nocturnal haemoglobinuria undergoing ravulizumab treatment].

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by hemolysis, thrombosis, and bone marrow failure. Infection, pregnancy, and surgical operation have the potential to evoke severe episodes of hemolysis and thrombosis. Therefore, the use of an antibody agent against complement component 5 (C5), eculizumab, one day before the operation is recommended. Ravulizumab is a newly approved long-acting antibody agent against C5. Thus, little is known about perioperative management with ravulizumab. We experienced a 43-year-old female patient who safely underwent laparoscopic cholecystectomy under ravulizumab treatment for PNH. Ravulizumab was administered one day before the operation. Laparoscopic cholecystectomy for cholelithiasis was performed under intravenous anesthesia, intermittent air compression of the lower extremities, and low pneumoperitoneum pressure. Additionally, heparin was administered, and the patient left the sickbed early without significant postoperative complications. Like eculizumab, complement inhibition by ravulizumab is also considered effective in the perioperative management of patients with PNH. However, close cooperation with surgeons and anesthesiologists and careful management based on clinical symptoms and laboratory data such as LDH, CH50, and D-dimer are essential.

A Rare Case of Radiation-Induced Liver Disease in Treated Abdominal Lymphoma Showing High [18F]FDG Avidity and Low EOB Uptake Proportional to the Irradiation Dose.

A 44-year-old woman presented with high [18F]FDG uptake liver lesion after six courses of R-CHOP and radiotherapy for abdominal DLBCL, which was misdiagnosed as a hepatic invasion. EOB-MRI showed slight T2 hyperintensity, low-intensity DWI, and decreased EOB uptake in the hepatocellular phase. Compared with the pretreatment planning CT, the liver lesion coincided with the area of >40.5 Gy, resulting in the diagnosis of RILD. At the follow-up [18F]FDG PET/CT 7 months after irradiation, the abnormal liver uptake disappeared. Comparing [18F]FDG PET/CT, EOB-MRI, and planning CT can lead to the correct diagnosis of RILD and avoid unnecessary biopsies and treatment changes.

A novel chimeric antigen receptor (CAR) system using an exogenous protease, in which activation of T cells is controlled by expression patterns of cell­surface proteins on target cells.

Anti­CD19 chimeric antigen receptor (CAR)­T cell therapy against refractory B­cell malignancies shows excellent therapeutic effects. However, there are some obstacles to be overcome in this treatment. Since current CAR­T cells target a single cell­surface protein on tumor cells, the CAR­T cells also attack normal cells expressing the protein. This is one of the major adverse effects of this therapy. To improve target­cell­specificity of this therapy, we established a novel CAR system, in which T­cell activation was controlled by expression patterns of proteins on target cells. Our novel CAR­T cells had two distinct CARs consisting of a 'Signal­CAR', recognizing a protein on tumor cells, and a 'Scissors­CAR', recognizing another protein on normal cells. The signal­CAR had a peptide sequence which was cleaved by the Scissors­CAR, and functional domains for cellular activation. The Scissors­CAR had a protease domain that cleaved its recognition peptide sequence in the Signal­CAR. When tumor cells expressed only the protein recognized by the Signal­CAR, the tumor cells were attacked. By contrast, normal cells expressing both the proteins induced inactivation of the Signal­CAR through cleavage of the recognition site when getting in contact with the CAR­T cells. To establish this system, we invented a Scissors­CAR that was dominantly localized on cell membranes and was activated only when the CAR­T cells were in contact with the normal cells. Using a T­cell line, Jurkat, and two proteins, CD19 and HER2, as target proteins, we showed that the anti­CD19­Signal­CAR was cleaved by the anti­HER2­Scissors­CAR when the CAR­T cells were co­cultivated with cells expressing both the proteins, CD19 and HER2. Furthermore, we demonstrated that primary CAR­T cells expressing both the CARs showed attenuated cytotoxicity againsT cells with both the target proteins. Our novel system would improve safety of the CAR­T cell therapy, leading to expansion of treatable diseases by this immunotherapy.

Successful treatment with bortezomib for refractory fever associated with myelodysplastic syndrome with underlying lymphoplasmacytic lymphoma.

We report a case of fever of unknown origin in a patient with MDS associated with IgM-MGUS. The patient was positive for MYD88 mutation, and chemotherapy for LPL/WM improved the fever. Analysis of MYD88 and the effect of chemotherapy on LPL/WM finally revealed the latent LPL/WM in this case.

Severe Motor Weakness Due to Disturbance in Peripheral Nerves Following Tisagenlecleucel Treatment.

BACKGROUND: Neurotoxicity is one of the dangerous complications of chimeric antigen receptor (CAR) T-cell therapy, while its pathophysiology remains to be fully understood. Motor weakness not associated with central nervous system (CNS) toxicity has rarely been reported after CAR T-cell therapy. CASE REPORT: A 42-year-old female with a refractory diffuse large B-cell lymphoma received tisagenlecleucel (tisa-cel) and developed cytokine release syndrome (CRS) on day 3. She was treated with tocilizumab and methylprednisolone, which resolved CRS promptly. On day 7, motor weakness in lower extremities appeared, and she gradually became unable to walk without showing any other symptoms attributed to CNS disturbances. Whereas dexamethasone and tocilizumab were ineffective, neuropathy improved after high dose chemotherapy followed by autologous stem cell transplantation. Nerve conduction study (NCS) in lower extremities showed a decline in compound muscle action potential amplitude along with worsening of motor weakness, which was restored after improvement of symptoms. Based on symptoms and NCS, her motor weakness was thought to be due to disturbance in peripheral nerves. CONCLUSION: This study reports a patient who developed severe motor weakness due to disturbance in peripheral nerves after tisa-cel therapy. Neurotoxicity of non-CNS origin should also be noted in CAR T-cell therapy.

[Marginal zone lymphoma-like primary bone marrow lymphoma with long-term pancytopenia preceding diagnosis].

A 45-year-old man initially diagnosed with aplastic anemia had been receiving treatment for >4 years when he visited our hospital for a detailed examination. On admission, bone marrow (BM) aspiration showed erythroid dysplasia and chromosomal abnormalities, including trisomy 3 in 1/20 cells. After 3 months of observation, BM aspiration showed the involvement of 5% abnormal lymphocytes, and flow cytometry revealed a monoclonal B-cell phenotype. After a further 5 months of observation, his blood test showed a sudden elevation in white blood cell (WBC) count and the presence of villous lymphocytes. Fluorodeoxyglucose-positron emission tomography (FDG-PET) only revealed strong uptake by systemic BM, and BM aspiration showed the involvement of 76.4% abnormal lymphocytes, which were positive for CD19 and dim CD11c; negative for CD25, CD103, cyclin D1, and BRAF-V600E; and exhibited light chain restriction. The patient was diagnosed with marginal zone lymphoma-like primary bone marrow (BM) lymphoma. Treatment with R-CHOP and R-cladribine failed. He then underwent an allogeneic peripheral blood stem cell transplantation from a human leucocyte antigen (HLA)-identical sibling, and he has since remained in good health and without relapse for 9 years. Further clinical and biological analyses are necessary to establish an optimal treatment strategy for this disease.

Inhibition of USP9X Downregulates JAK2-V617F and Induces Apoptosis Synergistically with BH3 Mimetics Preferentially in Ruxolitinib-Persistent JAK2-V617F-Positive Leukemic Cells.

JAK2-V617F plays a key role in the pathogenesis of myeloproliferative neoplasm. However, its inhibitor ruxolitinib has shown limited clinical efficacies because of the ruxolitinib-persistent proliferation of JAK2-V617F-positive cells. We here demonstrate that the USP9X inhibitor WP1130 or EOAI3402143 (G9) inhibited proliferation and induced apoptosis more efficiently in cells dependent on JAK2-V617F than on cytokine-activated JAK2. WP1130 preferentially downregulated activated and autophosphorylated JAK2-V617F by enhancing its K63-linked polyubiquitination and inducing its aggresomal translocation to block downstream signaling. Furthermore, JAK2-V617F associated physically with USP9X in leukemic HEL cells. Induction of apoptosis by inhibition of USP9X was mediated through the intrinsic mitochondria-mediated pathway, synergistically enhanced by BH3 mimetics, prevented by overexpression of Bcl-xL, and required oxidative stress to activate stress-related MAP kinases p38 and JNK as well as DNA damage responses in HEL cells. Although autophosphorylated JAK2-V617F was resistant to WP1130 in the ruxolitinib-persistent HEL-R cells, these cells expressed Bcl-2 and Bcl-xL at lower levels and showed an increased sensitivity to WP1130 as well as BH3 mimetics as compared with ruxolitinib-naive HEL cells. Thus, USP9X represents a promising target along with anti-apoptotic Bcl-2 family members for novel therapeutic strategies against JAK2-V617F-positive myeloproliferative neoplasms, particularly under the ruxolitinib persistence conditions.

FLT3-ITD Activates RSK1 to Enhance Proliferation and Survival of AML Cells by Activating mTORC1 and eIF4B Cooperatively with PIM or PI3K and by Inhibiting Bad and BIM.

FLT3-ITD is the most frequent tyrosine kinase mutation in acute myeloid leukemia (AML) associated with poor prognosis. We previously found that FLT3-ITD activates the mTORC1/S6K/4EBP1 pathway cooperatively through the STAT5/PIM and PI3K/AKT pathways to promote proliferation and survival by enhancing the eIF4F complex formation required for cap-dependent translation. Here, we show that, in contrast to BCR/ABL causing Ph-positive leukemias, FLT3-ITD distinctively activates the serine/threonine kinases RSK1/2 through activation of the MEK/ERK pathway and PDK1 to transduce signals required for FLT3-ITD-dependent, but not BCR/ABL-dependent, proliferation and survival of various cells, including MV4-11. Activation of the MEK/ERK pathway by FLT3-ITD and its negative feedback regulation by RSK were mediated by Gab2/SHP2 interaction. RSK1 phosphorylated S6RP on S235/S236, TSC2 on S1798, and eIF4B on S422 and, in cooperation with PIM, on S406, thus activating the mTORC1/S6K/4EBP1 pathway and eIF4B cooperatively with PIM. RSK1 also phosphorylated Bad on S75 and downregulated BIM-EL in cooperation with ERK. Furthermore, inhibition of RSK1 increased sensitivities to BH3 mimetics inhibiting Mcl-1 or Bcl-2 and induced activation of Bax, leading to apoptosis, as well as inhibition of proliferation synergistically with inhibition of PIM or PI3K. Thus, RSK1 represents a promising target, particularly in combination with PIM or PI3K, as well as anti-apoptotic Bcl-2 family members, for novel therapeutic strategies against therapy-resistant FLT3-ITD-positive AML.

Soluble Interleukin-2 Receptor Level at Diagnosis Predicts Prognosis of Patients With Follicular Lymphoma Irrespective of Initial Management Strategy.

BACKGROUND/AIM: Although various prognostic indices for follicular lymphoma (FL) have been proposed, they are designed specifically for patients requiring immediate therapy. We aimed to develop a new simple prognostic tool applicable for all patients with FL at diagnosis. MATERIALS AND METHODS: We retrospectively analyzed various clinical, pathological, and laboratory data, including soluble interleukin-2 receptor (sIL2R), from 140 patients with FL from two centers for their impact on prognosis. This study analyzed the impact of soluble interleukin-2 receptor (sIL2R) in order to develop a new simple prognostic tool applicable for all patients with FL at diagnosis. RESULTS: The initial management of these patients was watchful waiting (n=48) or immediate treatment (n=92). Event-free survival at 24 months predicted overall survival. When categorized into three groups according to the sIL2R levels at diagnosis, a very high sIL2R level identified about 20% of patients with a distinctively worse survival compared to the others. CONCLUSION: sIL2R is a very effective biomarker that can be easily applied in routine practice to predict survival for all patients with FL at diagnosis irrespective of initial management approach.

Methotrexate-associated Classical Hodgkin Lymphoma Shows Distinct Clinicopathological Features but Comparable Clinical Outcomes With Sporadic Cases.

BACKGROUND/AIM: Methotrexate (MTX)-associated classical Hodgkin lymphoma (CHL) is a rare disease, and its prognosis remains unclear. MATERIALS AND METHODS: Our study retrospectively compared clinicopathological features and clinical outcomes of patients with MTX-CHL (n=6) and sporadic CHL (n=40). RESULTS: MTX-CHL was more frequently the mixed cellularity subtype and positive for Epstein-Barr virus, but less frequently positive for CD20 than sporadic CHL. Clinically, MTX-CHL was more frequent in advanced stage than sporadic CHL and often associated with extranodal disease. After the cessation of MTX, transient spontaneous regression was observed in two MTX-CHL cases. Eventually, all patients with MTX-CHL required chemotherapy, which gave similar complete remission rates at 2 years compared to sporadic CHL. Patients with MTX-CHL tended to have a higher incidence of grade 3 or more neutropenia. CONCLUSION: The present study revealed differences in clinicopathological features but similarities in clinical outcomes of MTX-CHL and sporadic CHL.

[Novel therapies for acute myeloid leukemia based on genomic aberrations].

Standard treatment for acute myeloid leukemia (AML) comprises (1) induction therapy with both cytarabine and anthracycline and (2) consolidation therapy that is modified according to patients' conditions, including prognostic factors. However, this strategy is not satisfactory, especially for elderly patients. Novel technologies have revealed several driver mutations of numerous critical genes in AML, which can be targeted by novel drugs; the discovery of such targetable genes and the development of novel drugs have evolved the treatment strategy for AML. We should always monitor these advances in hematology. In the United States, the FDA has already approved several new drugs for AML, including FLT3 inhibitors and IDH neoenzyme inhibitors. In Japan, gilteritinib, an FLT3 inhibitor, was also approved at the end of 2018. These promising drugs will facilitate performing "precision medicine" on patients with AML soon.

Inhibition of USP9X induces apoptosis in FLT3-ITD-positive AML cells cooperatively by inhibiting the mutant kinase through aggresomal translocation and inducing oxidative stress.

FLT3-ITD and FLT3-TKD are the most frequent mutations in acute myeloid leukemia (AML) with the former associated with a poor prognosis. Here we show that inhibition of the deubiquitinase USP9X by its inhibitor WP1130 or EOAI3402143 (G9) induces apoptosis preferentially in cells transformed by these mutant kinases, including FLT3-ITD-positive AML cell line MV4-11 and primary AML cells. Mechanistically, WP1130 induced aggresomal translocation of the mutant kinases, particularly FLT3-ITD in its activated and autophosphorylated conformation, to block the downstream signaling events, which was aggravated by knock down of USP9X. Moreover, USP9X physically associated with FLT3-ITD to inhibit its K63-linked polyubiquitination, while FLT3-ITD induced tyrosine phosphorylation and degradation of USP9X through the ubiquitin/proteasome pathway. WP1130 or G9 also induced oxidative stress to stimulate stress-related MAP kinase pathways and DNA damage responses to activate in cooperation with inhibition of FLT3-ITD signaling the intrinsic mitochondria-mediated apoptotic pathway, which was synergistically enhanced by BH3 mimetics and prevented by overexpression of Bcl-xL or Mcl-1. Thus, USP9X represents a promising target for novel therapies against therapy-resistant FLT3-ITD-positive AML.