Silent NK/T cell reactions to dasatinib during sustained deep molecular response before cessation are associated with longer treatment-free remission.

This study presents the final report of the multicenter, prospective tyrosine kinase inhibitor discontinuation study, D-STOP, after a 3-year follow-up of 54 patients with chronic CML who discontinued dasatinib after a sustained deep molecular response (DMR) for ≥2 years with dasatinib treatment. Estimated treatment-free remission (TFR) rates at 12 and 36 months were 63.0% [95% confidence interval (CI): 48.7-74.3] and 59.3% (95% CI: 45.0-71.0), respectively. CD3- CD56+ NK, CD16+ CD56+ NK, and CD57+ CD56+ NK large granular lymphocyte (NK-LGL), CD8+ CD4- cytotoxic T cell, and CD57+ CD3+ T-LGL cell numbers were relatively elevated throughout the 24-month consolidation only in failed patients who molecularly relapsed within 12 months. In successful patients, these subsets elevated transiently after 12 months, but returned to basal levels after 24-month consolidation. Therefore, smaller changes in NK/T, particularly the NK subset throughout consolidation, reflected higher TFR rates. TFR rates of those patients exhibiting elevation in CD3- CD56+ NK >376 cells/µL, CD16+ CD56+ NK > 241 cells/µL, or CD57+ CD56+ NK-LGL >242 cells/µL during consolidation compared with others were 26.7% (8.3%-49.6%) vs 78.3% (55.4%-90.3%), HR 0.032 (0.0027-0.38; P = .0064), 31.2% (11.4%-53.6%) vs 85.0% (60.4%-94.9%), HR 0.039 (0.0031-0.48; P = .011), or 36.8% (16.5%-57.5%) vs 77.3% (53.7%-89.8%), HR 0.21 (0.065-0.69; P = .010), respectively. Therefore, silent responses of T/NK subsets to dasatinib throughout consolidation were significant for longer TFR. Elevated NK/T, particularly NK lymphocytes responsive to dasatinib, may be immunologically insufficient to maintain TFR. Their decline, subsequently replaced by altered lymphocyte population with less response to dasatinib during sustained DMR, might be immunologically significant. (D-STOP, NCT01627132).

Efficacy and Safety of a Weekly Cyclophosphamide-Bortezomib-Dexamethasone Regimen as Induction Therapy Prior to Autologous Stem Cell Transplantation in Japanese Patients with Newly Diagnosed Multiple Myeloma: A Phase 2 Multicenter Trial.

We assessed the efficacy and safety of weekly cyclophosphamide-bortezomib-dexamethasone (CBD) induction prior to autologous stem cell transplantation (ASCT) in newly diagnosed Japanese patients with multiple myeloma (MM). This regimen consisted of four 28-day cycles of once-weekly oral cyclophosphamide (300 mg/m2), subcutaneous bortezomib (1.3 mg/m2), and oral dexamethasone (40 mg). Responding patients underwent stem cell collection followed by ASCT. The primary endpoint was the postinduction rate of achieving a near complete response (nCR) or better. Among the 38 enrolled patients, a complete response (CR), an nCR, a very good partial response (VGPR), and a partial response (PR) were achieved in 10.5, 2.6, 23.7, and 36.8% of cases, respectively. A grade 4 hematological adverse event (AE) was observed in 1 patient. Grade 3-4 infection, including febrile neutropenia, was observed in 4 patients (10.5%). Although 2 patients dropped out due to AE, 94.7% of the patients completed the induction phase. However, because of a poor response to induction chemotherapy (

[Aggressive B-cell lymphoma with IGH/MYC, IGH/BCL2, and IGH/CCND1 translocations].

A 70-year-old man was admitted to our hospital due to fever, lymphadenopathy, and leukocytosis. White blood cell count was 22,700/µl with 92% blastoid cells. Bone marrow examination revealed abnormal lymphoid cell expansion. Abnormal cells expressed surface CD5 (dim), CD10, CD19, CD20, CD23 (dim) antigens, and kappa immunoglobulin light chains. Cytogenetic analysis of bone marrow cells at the time of diagnosis showed t (11:14) (q13;q32), t (14;18) (q32;q21), and t (8;14;18) (q24;q32;q21). Fluorescence in situ hybridization analyses of bone marrow identified translocations of IGH/MYC, IGH/BCL2, and IGH/CCND1. The patient was diagnosed with aggressive B-cell lymphoma with IGH/MYC, IGH/BCL2, and IGH/CCND1 translocation and was treated with various chemotherapies including R-CHOP, R-ESHAP, DA-EPOCH-R, R-hyper-CVAD, and radiotherapy. However, the lymphoma recurred after every chemotherapy session. Finally, he died after 6 months after first admission. Double-hit lymphoma/triple-hit lymphoma has previously been reported to present with an aggressive clinical course. In the present case, co-existence of IGH/CCND1, IGH/MYC, and IGH/BCL2 is very rare. Further clinical and biological investigations are necessary to establish an optimal treatment strategy.

Dasatinib cessation after deep molecular response exceeding 2 years and natural killer cell transition during dasatinib consolidation.

Tyrosine kinase inhibitors (TKI) improve the prognosis of patients with chronic myelogenous leukemia (CML) by inducing substantial deep molecular responses (DMR); some patients have successfully discontinued TKI therapy after maintaining DMR for ≥1 year. In this cessation study, we investigated the optimal conditions for dasatinib discontinuation in patients who maintained DMR for ≥2 years. This study included 54 patients with CML who were enrolled in a D-STOP multicenter prospective trial, had achieved DMR, and had discontinued dasatinib after 2-year consolidation. Peripheral lymphocyte profiles were analyzed by flow cytometry. The estimated 12-month treatment-free survival (TFS) was 62.9% (95% confidence interval: 48.5%-74.2%). During dasatinib consolidation, the percentage of total lymphocytes and numbers of CD3- CD56+ natural killer (NK) cells, CD16+ CD56+ NK cells and CD56+ CD57+ NK-large granular lymphocytes (LGL) were significantly higher in patients with molecular relapse after discontinuation but remained unchanged in patients without molecular relapse for >7 months. At the end of consolidation, patients whose total lymphocytes comprised <41% CD3- CD56+ NK cells, <35% CD16+ CD56+ NK cells, or <27% CD56+ CD57+ NK-LGL cells had higher TFS relative to other patients (77% vs 18%; P < .0008; 76% vs 10%; P < .0001; 84% vs 46%; P = .0059, respectively). The increase in the number of these NK cells occurred only during dasatinib consolidation. In patients with DMR, dasatinib discontinuation after 2-year consolidation can lead to high TFS. This outcome depends significantly on a smaller increase in NK cells during dasatinib consolidation.

Dasatinib rapidly induces deep molecular response in chronic-phase chronic myeloid leukemia patients who achieved major molecular response with detectable levels of BCR-ABL1 transcripts by imatinib therapy.

BACKGROUND: With the introduction of imatinib, a first-generation tyrosine kinase inhibitor (TKI) to inhibit BCR-ABL1 kinase, the outcome of chronic-phase chronic myeloid leukemia (CP-CML) has improved dramatically. However, only a small proportion of CP-CML patients subsequently achieve a deep molecular response (DMR) with imatinib. Dasatinib, a second-generation TKI, is more potent than imatinib in the inhibition of BCR-ABL1 tyrosine kinase in vitro and more effective in CP-CML patients who do not achieve an optimal response with imatinib treatment. METHODS: In the present study, we attempted to investigate whether switching the treatment from imatinib to dasatinib can induce DMR in 16 CP-CML patients treated with imatinib for at least two years who achieved a major molecular response (MMR) with detectable levels of BCR-ABL1 transcripts. RESULTS: The rates of achievement of DMR at 1, 3, 6 and 12 months after switching to dasatinib treatment in the 16 patients were 44% (7/16), 56% (9/16), 63% (10/16) and 75% (12/16), respectively. The cumulative rate of achieving DMR at 12 months from initiation of dasatinib therapy was 93.8% (15/16). The proportion of natural killer cells and cytotoxic T cells in peripheral lymphocytes increased after switching to dasatinib. In contrast, the proportion of regulatory T cells decreased during treatment. The safety profile of dasatinib was consistent with previous studies. CONCLUSION: Switching to dasatinib would be a therapeutic option for CP-CML patients who achieved MMR but not DMR by imatinib, especially for patients who wish to discontinue TKI therapy.

[Sustained deep molecular response over eight years after discontinuation of imatinib for chronic myeloid leukemia].

A 72-year-old female was diagnosed with chronic phase chronic myeloid leukemia (CML) in 2001. After a short course of treatment with hydroxycarbamide, imatinib (IM) 400 mg was started. A major molecular response was presumably acquired 10 months later. IM was discontinued after treatment for 47 months in November 2005. At the same time, BCR-ABL transcript was undetectable by nested RT-PCR assay, which was equivalent to <0.00138% BCR-ABL according to the international scale. The patient is still under observation with no additional therapy, and BCR-ABL has remained negative for 102 months, to date. Furthermore, interferon was never used in this patient. IM has dramatically improved the prognosis of CML. Since no cure has yet been established, patients are recommended to continue treatment even after achieving deep molecular responses. There are several ongoing clinical trials challenging the discontinuation of IM, but long-term observation is still lacking. The sustained deep molecular response, exceeding eight years, experienced in this patient is potentially encouraging.

Adult paroxysmal cold hemoglobinuria following mRNA COVID-19 vaccination.

Paroxysmal cold hemoglobinuria (PCH) is an extremely rare subtype of autoimmune hemolytic anemia (AIHA) in adults. PCH is caused by the biphasic Donath-Landsteiner (DL) antibody which fixes complement to red blood cells at low temperatures and dissociates at warmer temperatures, leading to complement-mediated intravascular hemolysis. Autoimmune hematological disorders including AIHA and immune thrombocytopenia have been reported to develop following the mRNA COVID-19 vaccination. However, PCH developing subsequent to mRNA vaccination has never been reported. We report a 59-year-old male who developed PCH approximately a month after his second mRNA COVID-19 vaccination.

Development of Acute Adult T-cell Leukemia Following PD-1 Blockade Therapy for Lung Cancer.

Immune checkpoint inhibitors (ICIs) are widely used for the treatment of various cancers. However, paradoxical exacerbation of neoplasms, referred to as "hyperprogressive disease," has been reported in a proportion of patients treated with anti-programmed cell death-1 (PD-1)/PD-1 ligand (PD-L1) blockade. We herein report a case of acute adult T-cell leukemia (ATL) that developed shortly after the administration of nivolumab, a PD-1 inhibitor, to treat non-small-cell lung cancer. There were no signs of ATL before the administration of nivolumab, and seropositivity for human T-cell leukemia virus type-1 (HTLV-1) was confirmed after the development of acute ATL. We speculate that nivolumab likely contributed to the development of acute ATL.

Asymmetric division and lineage commitment at the level of hematopoietic stem cells: inference from differentiation in daughter cell and granddaughter cell pairs.

How hematopoietic stem cells (HSCs) commit to a particular lineage is unclear. A high degree of HSC purification enabled us to address this issue at the clonal level. Single-cell transplantation studies revealed that 40% of the CD34-/low, c-Kit+, Sca-1+, and lineage marker- (CD34-KSL) cells in adult mouse bone marrow were able, as individual cells, to reconstitute myeloid and B- and T-lymphoid lineages over the long-term. Single-cell culture showed that >40% of CD34-KSL cells could form neutrophil (n)/macrophage (m)/erythroblast (E)/megakaryocyte (M) (nmEM) colonies. Assuming that a substantial portion of long-term repopulating cells can be detected as nmEM cells within this population, we compared differentiation potentials between individual pairs of daughter and granddaughter cells derived in vitro from single nmEM cells. One of the two daughter or granddaughter cells remained an nmEM cell. The other showed a variety of combinations of differentiation potential. In particular, an nmEM cell directly gave rise, after one cell division, to progenitor cells committed to nm, EM, or M lineages. The probability of asymmetric division of nmEM cells depended on the cytokines used. These data strongly suggest that lineage commitment takes place asymmetrically at the level of HSCs under the influence of external factors.

Acute promyelocytic leukemia presenting as recurrent spinal myeloid sarcomas 3 years before developing leukemia: A case report with review of literature.

The de novo myeloid sarcoma (MS) type of acute promyelocytic leukemia (APL) is rare, and clinical features may differ from extramedullary diseases in advanced APL. Many cases occur as a spinal tumor, and some occur in the absence of bone-marrow diseases or coagulation abnormalities. Fluorescence in situ hybridization analysis of MS tissue is useful for accurate diagnosis, even in preserved tissue.

The Efficacy of Reduced-dose Dasatinib as a Subsequent Therapy in Patients with Chronic Myeloid Leukemia in the Chronic Phase: The LD-CML Study of the Kanto CML Study Group.

Objective The aim of this study was to prospectively investigate the efficacy and safety profiles of low-dose dasatinib therapy (50 mg once daily). Methods Patients with chronic myeloid leukemia in the chronic phase (CML-CP) who were being treated with low-dose imatinib (≤200 mg/day), but were resistant to this agent were enrolled in the current study (referred to as the LD-CML study). Results There subjects included 9 patients (4 men and 5 women); all were treated with dasatinib at a dose of 50 mg once daily. Among 8 patients who had not experienced major molecular response (MMR; BCR-ABL1 transcript ≤0.1% according to International Scale [IS]) at study enrollment, 5 attained MMR by 12 months. In particular, 3 of 9 patients demonstrated a deep molecular response (DMR; IS ≤0.0069%) by 18 months. Five patients developed lymphocytosis accompanied by cytotoxic lymphocyte predominance. There was no mortality or disease progression, and all continue to receive dasatinib therapy at 18 months with only 2 patients requiring dose reduction. Toxicities were mild-to-moderate, and pleural effusion was observed in 1 patient (grade 1). Conclusion Low-dose dasatinib can attain MMR and DMR without severe toxicity in patients with CML-CP who are unable to achieve MMR with low-dose imatinib. Switching to low-dose dasatinib should therefore be considered for patients in this setting, especially if they are otherwise considering a cessation of treatment.

Myelodysplastic hematopoiesis mimicking the bone marrow in a mediastinal myelolipoma.

Myelolipoma is one of the rare causes of posterior mediastinal tumor. Surgical excision is effective, which differs from the treatment of extramedullary disease usually concomitant with myelodysplastic syndrome. Cytogenetic analysis suggests the bone marrow cell originating myelolipoma.

A retrospective cohort study of venous thromboembolism(VTE) in 1035 Japanese myeloma patients treated with thalidomide; lower incidence without statistically significant association between specific risk factors and development of VTE and effects of thromboprophylaxis with aspirin and warfarin.

BACKGROUND: Rate of thalidomide-related VTE and risk factors in Japanese myeloma patients are not clear and effects of thromboprophylaxis remain controvertial. PATIENTS AND METHODS: We retrospectively analyzed a cohort data of registered Japanese myeloma patients treated with thalidomide-based regimens between 2009 and 2010. Primary endpoint was rate of symptomatic VTE. Secondary endpoints were associations between VTE and clinical factors including age, gender, disease characteristics and duration, history of VTE, immobilization, comorbidities, treatment regimens, and laboratory parameters of Hb, leukocyte, platelet and FDP or D-dimer level, and effects of thromboprophylaxis with aspirin or warfarin. Statistical analysis was performed by Fischer's exact test and Cochran-Mantel-Haenszel test to control for confounders, and t test for dichotomous and continuous variables, respectively. RESULTS: 1035 refractory or relapsed myeloma patients were followed up for a median of 112days(range 2-311days), and 14 (1.4%) developed VTE with a median treatment of 31days (range 9-134days) with thalidomide. Treatments with or without other agents lead to similar rates of VTE, 1.7% and 1.1%, respectively (p=0.43) and no specific clinical factors influenced development of VTE. Thromboprophylaxis with aspirin or warfarin did not reduce risk of VTE; VTE with or without aspirin: 1.4% and 1.3% (p=1.00), and warfarin: 2.4% and 1.3% (0.31), respectively. CONCLUSIONS: Rate of VTE is low in Japanese myeloma patients treated with thalidomide. Risk factors and effects of thromboprophylaxis with aspirin or warfarin are not apparent, however, controlled randomized studies of larger scale are needed for statistically valid conclusion.

Adult mouse hematopoietic stem cells: purification and single-cell assays.

Mouse hematopoietic stem cells (HSCs) are the best-studied stem cells because functional assays for mouse HSCs were established earliest and purification techniques for mouse HSCs have progressed furthest. Here we describe our current protocols for the purification of CD34-/lowc-Kit+Sca-1+lineage marker- (CD34-KSL) cells, the HSC population making up approximately 0.005% of bone marrow cells in adult C557BL/6 mice. Purified HSCs have been characterized at cellular and molecular levels. Since clonal analysis is essential for the study of self-renewal and lineage commitment in HSCs, here we present our single-cell colony assay and single-cell transplantation procedures. We also introduce our immunostaining procedures for small numbers of HSCs, which are useful for signal transduction analysis. The purification of CD34-KSL cells requires approximately 6 h. Initialization of single-cell culture requires approximately 1 h. Single-cell transplantation requires approximately 6 h. Single-cell immunostaining requires approximately 2 d.