[Infection risks and prevention in patients with multiple myeloma].

Multiple myeloma (MM) is a hematological malignancy characterized by aberrant clonal plasma cells in the bone marrow. Despite significant advances in the treatment of MM, infection remains a main cause of death. MM patients have an increased risk of infection compared to their healthy counterparts due to several factors related to underlying disease, advanced age, comorbidities, and MM treatment. MM patients are at high risk of infection during the first 3 months after diagnosis and during relapse. Anti-myeloma drugs frequently result in severe immunosuppression and increased risk of infection. Proteasome inhibitors deplete T cells, lenalidomide and pomalidomide induce neutropenia, and CD38 antibodies reduce B cell function. To prevent infection in MM patients, we should take appropriate action by medical prophylaxis and vaccination.

EMD originates from hyaluronan-induced homophilic interactions of CD44 variant-expressing MM cells under shear stress.

Extramedullary disease (EMD) is known to be associated with chemoresistance and poor prognosis in multiple myeloma (MM); however, the mechanisms of its development are not fully understood. Elucidating the mechanism of EMD development and its therapeutic targeting would greatly contribute to further improvement of treatment outcome in patients with MM. Here, we show that bone marrow stroma cell-derived hyaluronan (HA) elicits homophilic interactions of MM cells by binding to surface CD44, especially long-stretch variants, under physiological shear stress and generates cell clusters that might develop into EMD. We recapitulated the development of EMD via administration of HA in a syngeneic murine MM model in a CD44-dependent manner. HA-induced MM cell clusters exhibited the specific resistance to proteasome inhibitors (PIs) in vitro and in murine models via γ-secretase-mediated cleavage of the intracellular domains of CD44, which in turn transactivated PI resistance-inducible genes. Treatment of HA-injected mice with anti-CD44 antibody or γ-secretase inhibitors readily suppressed the development of EMD from transplanted MM cells and significantly prolonged the survival of recipients by overcoming PI resistance. The HA-CD44 axis represents a novel pathway to trigger EMD development and could be a target of the prediction, prevention, and treatment of EMD in patients with MM.

[Autoimmune acquired coagulation factor XIII/13 deficiency caused by type Ab anti-FXIII-A autoantibody].

An 88-year-old man became unconscious and was admitted to our hospital due to severe anemia. Extensive subcutaneous hemorrhage around the chest and back and pectoralis major muscle hematoma were observed. Coagulation screening tests showed moderately reduced factor XIII/13 (FXIII) activity. During hospitalization, the patient had repeated bleeding events in the gastrointestinal tract and muscles, leading to hemorrhagic shock. We suspected the presence of FXIII inhibitors from FXIII infusion test results. The cross-mixing test for cross-linking of fibrin revealed inhibition of polymerization of α-chain and α2-plasmin inhibitor incorporation into fibrin. In addition, by detecting IgG autoantibody to thrombin-activated FXIII, we confirmed the presence of type Ab anti-FXIII-A subunit autoantibody, which represses the catalytic subunit activity of activated FXIII. Autoimmune FXIII deficiency should be considered when a patient presents with severe hemorrhagic diathesis with no other cause than moderately reduced of FXIII activity, as reported in this case.

Outcomes of poor peripheral blood stem cell mobilizers with multiple myeloma at the first mobilization: A multicenter retrospective study in Japan.

Autologous stem cell transplantation (ASCT) remains an important therapeutic strategy for multiple myeloma; however, a proportion of patients fail to mobilize a sufficient number of peripheral blood stem cells (PBSCs) to proceed to ASCT. In the present study, we aimed to clarify the characteristics and outcomes of poor mobilizers. Clinical data on poorly mobilized patients who underwent PBSC harvest for almost 10 years were retrospectively collected from 44 institutions in the Japanese Society of Myeloma (JSM). Poor mobilizers were defined as patients with less than 2 × 106/kg of CD34+ cells harvested at the first mobilization. The proportion of poor mobilization was 15.1%. A sufficient dataset including overall survival (OS) was evaluable in 258 poor mobilizers. Overall, 92 out of 258 (35.7%) poor mobilizers did not subsequently undergo ASCT, mainly due to an insufficient number of PBSCs. Median OS from apheresis was longer for poor mobilizers who underwent ASCT than for those who did not (86.0 vs. 61.9 mon., p = 0.02). OS from the diagnosis of poor mobilizers who underwent ASCT in our cohort was similar to those who underwent ASCT in the JSM database (3y OS rate, 86.8% vs. 85.9%). In this cohort, one-third of poor mobilizers who did not undergo ASCT had relatively poor survival. In contrast, the OS improved in poor mobilizers who underwent ASCT. However, the OS of extremely poor mobilizers was short irrespective of ASCT.

Autophagic degradation of NOXA underlies stromal cell-mediated resistance to proteasome inhibitors in mantle cell lymphoma.

Mantle cell lymphoma (MCL) is usually resistant to the current standard-of-care regimens and also to novel agents such as the proteasome inhibitor bortezomib. A better prognosis of leukemic variants of MCL suggests that MCL cells acquire drug resistance in nodal and/or bone marrow microenvironments via interaction with supporting cells. Bortezomib exerts cytotoxic action in MCL cells via stabilization of the pro-apoptotic BCL-2 family protein NOXA. Here we show that autophagic degradation of NOXA is a mechanism of bortezomib resistance in MCL cells in a tumor microenvironment. First, we demonstrated that interaction with bone marrow-derived or nodal stromal cells conferred bortezomib resistance to MCL cells in vitro and in a murine model. Co-culture of MCL cells with stromal cells enhanced bortezomib-induced ubiquitination and subsequent binding of NOXA to the p62 adaptor, which escorted NOXA to the lysosome for autophagic degradation. Finally, we found that not only direct contact with stromal cells but also stroma-derived humoral factors, especially interleukin-6, promoted selective autophagy and NOXA degradation in MCL cells. Targeting protective autophagy, for example, using the lysosome inhibitor chloroquine, might increase the efficacy of bortezomib-containing regimens in MCL.

AMP-activated protein kinase activation primes cytoplasmic translocation and autophagic degradation of the BCR-ABL protein in CML cells.

Chronic myeloid leukemia is driven by the BCR-ABL oncoprotein, a constitutively active protein tyrosine kinase. Although tyrosine kinase inhibitors (TKIs) have greatly improved the prognosis of CML patients, the emergence of TKI resistance is an important clinical problem, which deserves additional treatment options based on unique biological properties to CML cells. In this study, we show that metabolic homeostasis is critical for survival of CML cells, especially when the disease is in advanced stages. The BCR-ABL protein activates AMP-activated protein kinase (AMPK) for ATP production and the mTOR pathway to suppress autophagy. BCR-ABL is detected in the nuclei of advanced-stage CML cells, in which ATP is sufficiently supplied by enhanced glucose metabolism. AMP-activated protein kinase is further activated under energy-deprived conditions and triggers autophagy through ULK1 phosphorylation and mTOR inhibition. In addition, AMPK phosphorylates 14-3-3 and Beclin 1 to facilitate cytoplasmic translocation of nuclear BCR-ABL in a BCR-ABL/14-3-3τ/Beclin1/XPO1 complex. Cytoplasmic BCR-ABL protein undergoes autophagic degradation when intracellular ATP is exhausted by disruption of the energy balance or forced autophagy flux with AMP mimetics, mTOR inhibitors, or arsenic trioxide, leading to apoptotic cell death. This pathway represents a novel therapeutic vulnerability that could be useful for treating TKI-resistant CML.

Comparison of prognostic scores in transplant-ineligible patients with peripheral T-cell lymphoma not otherwise specified and angioimmunoblastic T-cell lymphoma: a retrospective study from the national hospital organization in Japan.

We retrospectively analyzed the risk factors for outcomes among patients with peripheral T-cell lymphoma not otherwise specified (PTCL-NOS, n = 100) and angioimmunoblastic T-cell lymphoma (AITL, n = 128) who did not receive hematopoietic stem cell transplantation between 2008 and 2018. We designed a comparison of prognostic scores specifically for PTCL-NOS and AITL. The international prognostic index (IPI) was useful for investigating the risk factors associated with outcomes among transplant-ineligible patients with PTCL-NOS (Harrell's c-statistic 0.715) and AITL (c-statistic 0.615). The prognostic index for T-cell lymphoma (PIT), modified PIT, and the International Peripheral T Cell Lymphoma Project for overall survival (OS) seemed to identify separate prognostic groups, based on visual assessment of Kaplan-Meier curves. However, better c-statistics (>0.7) were only found for the IPI score for OS in PTCL-NOS. Strategies that carefully select PTCL patients with higher IPI scores may help to identify individuals suitable for novel therapies.

Successful treatment with gilteritinib for isolated extramedullary relapse of acute myeloid leukemia with FLT3-ITD mutation after allogeneic stem cell transplantation.

Acute myeloid leukemia (AML) harboring Fms-like tyrosine kinase 3 (FLT3) internal tandem duplication (ITD) mutation is associated with shorter remission and higher relapse risk. Several FLT3 inhibitors have been used in clinical trials, but their efficacy in extramedullary disease remains unclear. In the present case, a 56-year-old man was diagnosed with FLT3-ITD mutated AML. Due to bone marrow relapse during consolidation therapy, he underwent salvage therapy and a myeloablative conditioning regimen, followed by peripheral blood stem cell transplantation (PBSCT) from a HLA-matched related donor. Acute graft-versus-host disease (GVHD) did not develop, and complete donor chimerism was confirmed on days 27 and 96 after PBSCT. On day 180, he experienced extensive chronic GVHD and had several subcutaneous tumors in his body, which were diagnosed as myeloid sarcoma by pathological examination. We considered this to be a case of isolated extramedullary relapse, as his bone marrow had maintained complete donor chimerism. Treatment with etoposide and ranimustine produced no effect, and tumor progression continued. We started administration of gilteritinib, a FLT3/AXL inhibitor, after identifying the FLT3-ITD mutation in the tumor. Subsequently, there has been a remarkable regression of the tumors. Gilteritinib can be effective in isolated extramedullary relapse after allogeneic stem cell transplantation.

High-dose dexamethasone therapy as the initial treatment for idiopathic thrombocytopenic purpura.

There is a controversy which short term high dose dexamethasone therapy (HDD) or standard dose prednisolone therapy as the initial treatment leads to long term efficacy in idiopathic thrombocytopenic purpura (ITP) patients. We conducted a multicenter, prospective trial to determine the efficacy and safety of short-term HDD in ITP patients aged 18-80 years with platelet counts of < 20 × 109/l, or < 50 × 109/l and bleeding symptoms. The primary endpoints are the proportion of complete response (CR) plus partial response (R) on day 180 after the completion of the 46-day HDD. Twenty-three patients were enrolled. Test for Helicobacter pylori (H. pylori) was positive for 6 patients and negative for 17 patients. In positive patients, 5 were received successful H. pylori eradication therapy. The proportion of CR + R was 60.9% (14/23) with 90% confidence interval of 41.7-77.8%. For patients with positive H. pylori and successful eradication, the proportion of CR + R was 80.0% (4/5). There was one grade 4 adverse event. Although we have enrolled relatively old, severe ITP patients with a median age of 63 years in this study, the efficacy was comparable to the reported clinical trials with HDD therapy.

Soluble SLAMF7 promotes the growth of myeloma cells via homophilic interaction with surface SLAMF7.

SLAMF7 is expressed mainly on multiple myeloma (MM) cells and considered an ideal target for immunotherapeutic approaches. Indeed, elotuzumab, an anti-SLAMF7 antibody, is used for the treatment of MM in combination with immunomodulatory drugs. SLAMF7 is cleaved via unknown mechanisms and detected as a soluble form (sSLAMF7) exclusively in the serum of MM patients; however, little is known about the role of sSLAMF7 in MM biology. In this study, we found that sSLAMF7 enhanced the growth of MM cells via homophilic interaction with surface SLAMF7 and subsequent activation of the SHP-2 and ERK signaling pathways. Elotuzumab suppressed sSLAMF7-induced MM cell growth both in vitro and in vivo. Promoter analyses identified IKZF1 (Ikaros) as a pivotal transcriptional activator of the SLAMF7 gene. Pharmacological targeting of Ikaros by lenalidomide and its analog pomalidomide downregulated SLAMF7 expression and ameliorated the response of MM cells to sSLAMF7. Elotuzumab blocked the growth-promoting function of sSLAMF7 when combined with lenalidomide in a murine xenograft model. Neutralization of sSLAMF7 is a novel antimyeloma mechanism of elotuzumab, which is enhanced by immunomodulatory drugs via downregulation of surface SLAMF7 expression on MM cells. These findings may provide important information for the optimal use of elotuzumab in MM treatment.

Evaluation of the Revised International Staging System (R-ISS) in Japanese patients with multiple myeloma.

In spite of recent development in the treatment armamentarium for multiple myeloma, overall survival (OS) still depends on risk status and sensitivity to treatment of each patient. We have evaluated the clinical relevance of the Revised International Staging System (R-ISS) by comparing it with the original ISS in 718 Japanese patients. The distribution of patients according to response was similar between the ISS and R-ISS stages. Treatment response was greatly influenced by initial treatment modalities and deeper response was observed more frequently in transplanted patients. The R-ISS discriminated the difference in OS between the stages more distinctly than the ISS (p = 9.0 × 10-15 and p = 4.0 × 10-10, respectively). Differences in OS were clarified by both R-ISS and ISS in non-transplanted patients (p = 2.4 × 10-12 and p = 1.4 × 10-8, respectively), but the ISS failed to distinguish the difference between the stages in transplanted patients (p = 0.13). In contrast, the R-ISS could at least discriminate the excellent prognosis of stage I patients whereas the distinction between stage II and III was not that clear (p = 0.033). The R-ISS stage II encompassed a large number of patients, and the prognosis was heterogeneous depending on the fulfillment of prognostic factors such as LDH and adverse cytogenetics. These results suggest that treatment factors and prognostic factors greatly affect the therapeutic response and outcome, and the R-ISS is superior to ISS in prognostication of both transplant-eligible and -ineligible patients in our current clinical practice.

Bortezomib-based strategy with autologous stem cell transplantation for newly diagnosed multiple myeloma: a phase II study by the Japan Study Group for Cell Therapy and Transplantation (JSCT-MM12).

BACKGROUND: The Japan Study Group for Cell Therapy and Transplantation (JSCT) organized a phase II study to evaluate the efficacy and safety of a treatment protocol (JSCT-MM12) for multiple myeloma (MM) patients who were previously untreated and transplantation-eligible. Since bortezomib-based therapy is known to be effective for MM, the protocol is intensified more than the previous protocol (JSCT-MM10) and comprised the subsequent treatments: bortezomib + cyclophosphamide + dexamethasone (VCD) induction; bortezomib + high-dose-melphalan (B-HDM) conditioning with autologous stem cell transplantation (ASCT); bortezomib + thalidomide + dexamethasone (VTD) consolidation; and lenalidomide (LEN) maintenance. METHODS: Sixty-four symptomatic patients aged between 20 and 65 years were enrolled for treatment and received three cycles of VCD, followed by cyclophosphamide administration for autologous stem cell harvest and B-HDM/ASCT, and subsequently two cycles of VTD, after that LEN for 1 year. RESULTS: Complete response (CR)/stringent CR (sCR) rates for induction, ASCT, consolidation, and maintenance therapies were 20, 39, 52, and 56%, respectively. The grade 3/4 toxicities (≥ 10%) with VCD treatment included neutropenia (27%), anemia (19%), and thrombocytopenia (11%). There was no treatment-related mortality. After median follow-up of 41 months, estimated 3-year progression-free survival (PFS) and overall survival (OS) rates were 64% and 88%, respectively. The high-risk group revealed lower CR/sCR, PFS, and OS than the standard-risk group. CONCLUSIONS: The study revealed that the treatment protocol consisting of VCD induction, B-HDM/ASCT followed by VTD consolidation, and LEN maintenance could produce highly beneficial responses and favorable tolerability in newly diagnosed MM. However, future study is required for improving treatment in the high-risk group.

Correction to: A phase II study of lenalidomide consolidation and maintenance therapy after autologous PBSCT in patients with multiple myeloma.

In the original publication of this article, "Conflict of interest" was published incorrectly. The corrected "Conflict of interest" is given below for your reading.

A phase II study of lenalidomide consolidation and maintenance therapy after autologous PBSCT in patients with multiple myeloma.

The efficacy and safety of lenalidomide (LEN) consolidation therapy and subsequent LEN maintenance therapy after high-dose therapy with autologous peripheral blood stem cell transplantation (auto-PBSCT) were evaluated in patients with newly diagnosed symptomatic multiple myeloma (MM). Forty-one patients were enrolled and received high-dose dexamethasone (DEX) therapy as an initial induction. The patients who did not respond to the DEX therapy were further treated with four cycles of bortezomib plus DEX (BD) induction therapy. For patients who responded to BD, PBSC harvesting was scheduled following high-dose cyclophosphamide and filgrastim administration. After PBSC harvesting, high-dose chemotherapy of melphalan with auto-PBSCT was performed. One hundred days after auto-PBSCT, patients received consolidation therapy consisting two cycles of LEN plus low-dose DEX (Ld) and LEN maintenance therapy. Only one death occurred during mobilization therapy, but the protocol developed in this study was considered generally safe to provide. Overall response rates after consolidation and maintenance therapies were 73.7% and 81.6%, respectively. Two-year progression-free survival and overall survival were 76.3% and 92.1%, respectively. These observations suggest that LEN consolidation and maintenance therapy are effective and safe, and provide favorable response rates in patients with MM.

Eradication of Central Nervous System Leukemia of T-Cell Origin with a Brain-Permeable LSD1 Inhibitor.

PURPOSE: Lysine-specific demethylase 1 (LSD1) regulates several biological processes via the bifunctional modulation of enhancer functions. Recently, we reported that LSD1 overexpression is a founder abnormality of T-cell leukemogenesis and is maintained in fully transformed T-cell acute lymphoblastic leukemia (T-ALL) cells. On the basis of this finding, we attempted to develop novel LSD1 inhibitors effective for T-ALL with central nervous system (CNS) involvement. EXPERIMENTAL DESIGN: We chemically modified the prototype LSD inhibitor tranylcypromine (TCP) and screened for cytotoxicity against TCP-resistant T-ALL cell lines. In vivo efficacy of novel LSD1 inhibitors was examined in immunodeficient mice transplanted with luciferase-expressing T-ALL cell lines, which faithfully reproduce human T-ALL with CNS involvement. RESULTS: We found robust cytotoxicity against T-ALL cells, but not normal bone marrow progenitors, for two N-alkylated TCP derivatives, S2116 and S2157. The two compounds induced apoptosis in TCP-resistant T-ALL cells in vitro and in vivo by repressing transcription of the NOTCH3 and TAL1 genes through increased H3K9 methylation and reciprocal H3K27 deacetylation at superenhancer regions. Both S2116 and S2157 significantly retarded the growth of T-ALL cells in xenotransplanted mice and prolonged the survival of recipients as monotherapy and in combination with dexamethasone. Notably, S2157 could almost completely eradicate CNS leukemia because of its ability to efficiently pass through the blood-brain barrier. CONCLUSIONS: These findings provide a molecular basis and rationale for the inclusion of a brain-permeable LSD1 inhibitor, S2157, in treatment strategies for T-ALL with CNS involvement.

Unsuppressed serum albumin levels may jeopardize the clinical relevance of the international staging system to patients with light chain myeloma.

The international staging system (ISS) is the most commonly used risk-stratification system for patients with multiple myeloma (MM) and is determined by serum albumin and ß2-microglobulin levels. In the two determinants, ß2-microglobulin levels are frequently observed to be elevated in patients with myeloma, particularly in those with renal impairment. In comparison with patients with intact immunoglobulin myeloma, patients with LC myeloma do not necessarily show decreased levels of serum albumin. The clinical impact of ISS in patients with LCMM, in particular the distinction between ISS I and II, may be complicated due to non-decreased levels of serum albumin in both stages. Accordingly, we have attempted to assess clinical relevance of the ISS in patients with LC myeloma. The clinical data of 1899 patients with MM diagnosed between January 2001 and December 2012 were collected from 38 affiliated hospitals of the Japanese Society of Myeloma. Significant difference was not found between stage I (n = 72) and stage II (n = 92) in LC myeloma patients (n = 307). The mean serum albumin concentration of patients with LC myeloma was within the reference range but higher than that of patients with IgG + IgA myeloma (n = 1501), which complicates the distinction between ISS stage I and II myeloma. Patients with LC myeloma had low frequencies of t(4; 14) and high frequency of elevated lactate dehydrogenase, and despite a relevant amount of missing data in our registry (R-ISS stage I; n = 11, stage II; n = 32, and stage III: n = 18), the information included in the R-ISS scoring system seems to be more accurate than ISS to obtain a reliable risk stratification approach in non-ISS stage III LC myeloma patients.

[Involvement of innate immunity in the expansion of multiple myeloma cells and therapeutic intervention with lenalidomide].

Multiple myeloma (MM) cells acquire dormancy and drug resistance via their interaction with bone marrow stroma cells (BMSCs) in a hypoxic microenvironment. In this study, we found a positive expression of CD180/MD-1 complex (a non-canonical toll-like receptor) on MM cells, which was markedly up-regulated under adherent and/or hypoxic conditions. Bacterial lipopolysaccharide (LPS) enhanced the growth of MM cells via the activation of MAP kinases, an effect which showed a positive correlation with the expression levels of CD180. LPS administration significantly increased CD180/CD138 double-positive cell number in a murine xenograft model after the inoculation of MM cells directly attached to BMSCs. Notably, the shRNA-mediated knockdown of CD180 terminated the LPS response in vitro and in vivo. Promoter analyses identified IKZF1 (Ikaros) as a pivotal transcriptional activator of the CD180 gene, whose transcription was activated via cell adhesion and hypoxia by increasing Ikaros expression and its binding to the promoter region. Pharmacological targeting of Ikaros with lenalidomide ameliorated the response of MM cells to LPS in a CD180-dependent manner in vitro and in vivo. CD180/MD-1 pathway may represent a novel mechanism for the regulation of the growth of MM cells in BM milieu and may serve as a therapeutic target to prevent the regrowth of dormant MM cells.

Myeloma Cells Are Activated in Bone Marrow Microenvironment by the CD180/MD-1 Complex, Which Senses Lipopolysaccharide.

Multiple myeloma (MM) cells acquire dormancy and drug resistance via interaction with bone marrow stroma cells (BMSC) in a hypoxic microenvironment. Elucidating the mechanisms underlying the regrowth of dormant clones may contribute to further improvement of the prognosis of MM patients. In this study, we find that the CD180/MD-1 complex, a noncanonical lipopolysaccharide (LPS) receptor, is expressed on MM cells but not on normal counterparts, and its abundance is markedly upregulated under adherent and hypoxic conditions. Bacterial LPS and anti-CD180 antibody, but not other Toll-like receptor ligands, enhanced the growth of MM cells via activation of MAP kinases ERK and JNK in positive correlation with expression levels of CD180. Administration of LPS significantly increased the number of CD180/CD138 double-positive cells in a murine xenograft model when MM cells were inoculated with direct attachment to BMSC. Knockdown of CD180 canceled the LPS response in vitro and in vivo Promoter analyses identified IKZF1 (Ikaros) as a pivotal transcriptional activator of the CD180 gene. Both cell adhesion and hypoxia activated transcription of the CD180 gene by increasing Ikaros expression and its binding to the promoter region. Pharmacological targeting of Ikaros by the immunomodulatory drug lenalidomide ameliorated the response of MM cells to LPS in a CD180-dependent manner in vitro and in vivo Thus, the CD180/MD-1 pathway may represent a novel mechanism of growth regulation of MM cells in a BM milieu and may be a therapeutic target of preventing the regrowth of dormant MM cells.Significance: This study describes a novel mechanism by which myeloma cells are regulated in the bone marrow, where drug resistance and dormancy can evolve after treatment, with potential therapeutic implications for treating this often untreatable blood cancer. Cancer Res; 78(7); 1766-78. ©2018 AACR.