[Recommendations for the treatment of premature ejaculation]. / Recommandations pour le traitement de l'éjaculation prématurée.

OBJECTIVES: The Post-University Interdisciplinary Association of Sexology (AIUS) has brought together a panel of experts to develop French recommendations for the management of premature ejaculation. METHODS: Systematic review of the literature between 01/1995 and 02/2022. Use of the clinical practice guidelines (CPR) method. RESULTS: We recommend giving all patients with PE psychosexological counseling, and whenever possible combining pharmacotherapies and sexually-focused cognitive-behavioral therapies, involving the partner in the treatment process. Other sexological approaches could be useful. We recommend the use of dapoxetine as first-line, on-demand oral therapy for primary and acquired PE. We recommend the use of lidocaine 150mg/mL/prilocaine 50mg/mL spray as local treatment for primary PE. We suggest the combination of dapoxetine and lidocaine/prilocaine in patients insufficiently improved by monotherapy. In patients who have not responded to treatments with marketing authorisation, we suggest using an off-label SSRI, preferably paroxetine, in the absence of a contraindication. We recommend treating ED before PE in patients with both symptoms. We do not recommend using α-1 blockers or tramadol in patients with PE. We do not recommend routine posthectomy or penile frenulum surgery for PE. CONCLUSION: These recommendations should contribute to improving the management of PE.

Mavacamten: A Novel Disease-Specific Treatment for Hypertrophic Cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is characterized by an abnormal thickening of the myocardium, leading to left ventricular outflow tract obstruction. Current treatments for HCM include non-disease-specific medications such as beta blockers or invasive interventions. Mavacamten has been studied for its effects on adenosine triphosphatase, myocardial-specific sarcomeric proteins, and myocardial tissue calcium sensitivity. Given these properties, mavacamten could be used as a disease-specific treatment for HCM. Clinical trials of mavacamten have shown improvements in left ventricular outflow tract obstruction among other favorable improvements in biochemical markers and the clinical symptoms of the disease. While trials to date have been relatively small, mavacamten shows promise as a future disease-specific treatment for HCM.

Successful Mobilization of Autologous Hematopoietic Peripheral Blood Stem Cells after Salvage Chemotherapy in Patients with Low CD34 Blood Cell Counts.

A major barrier for proceeding to autologous stem cell transplantation (ASCT) is an inability to mobilize and collect an adequate number of peripheral blood (PB) stem cells (PBSC) for the transplant graft. Plerixafor added to granulocyte colony stimulating factor (G-CSF) alone, without prior chemotherapy, significantly improves the mobilization of autologous PBSC in patients with non-Hodgkin lymphoma (NHL) and multiple myeloma (MM). However, the efficacy of plerixafor and the best timing to give the drug to poorly mobilizing patients with very low PB CD34+ cell counts after salvage chemotherapy and G-CSF are not well defined. We hypothesized that PBSC mobilization and collection might be improved in heavily treated patients who mobilized very poorly after salvage chemotherapy and G-CSF by alternating the days of plerixafor administration and leukapheresis. A day of rest between plerixafor doses, while continuing G-CSF, could allow time for some replenishment of the marrow stem/progenitor cell pool before the next mobilization. A retrospective review of collection results in poorly mobilizing patients at our center was undertaken. Three cohorts were identified: those who got every-other-day plerixafor and leukapheresis, those who got sequential plerixafor and leukapheresis and those who got risk adapted plerixafor. Overall, 69% of patients with NHL and MM with PB CD34+ cell counts <5/µL after salvage chemotherapy and G-CSF were ultimately able to collect adequate CD34+ cells to support ASCT using daily plerixafor and leukapheresis. On the alternating plerixafor and leukapheresis schedule, all 17 patients achieved the cumulative CD34+ cell product goals required for ASCT. This positive observation after salvage chemotherapy and G-CSF led to the incorporation at our center of an alternate-day schedule of plerixafor and leukapheresis into our real-time risk adapted strategy for poor mobilizers. © 2023 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

MEdical Database AnaLysIS of Japanese multiple myeloma patienTs with apheresis #2 (MEDALIST-2): the impact of plerixafor use on costs and healthcare resources during mobilization and stem cell transplantation.

Treatment for multiple myeloma (MM) can involve apheresis to mobilize hematopoietic stem cells for later autologous stem cell transplantation (ASCT), which can become costly over time. This retrospective claims database study examined healthcare resource use and medical costs associated with plerixafor, a selective CXCR4 inhibitor that mobilizes hematopoietic stem cells and minimizes apheresis times. Medical data were sampled from Japanese MM patients between April 2017 and September 2019, after the Japanese launch of plerixafor. The study population (190 plerixafor users and 180 non-users) was identified from the Medical Data Vision database, and further stratified into those using granulocyte-colony stimulating factor in monotherapy or in combination with cyclophosphamide to trigger apheresis. A descriptive comparison of patient characteristics, healthcare resource use, and medical costs across the mobilization and ASCT phases indicated plerixafor is associated with higher average total medical costs. However, plerixafor-treated patients received fewer concomitant medications and spent less time in apheresis than non-users. A comparison of non-users with a similar analysis conducted pre-plerixafor launch (2013-2017) showed general improvements to treatment independent of plerixafor. The results of this research can inform guidelines for the role of plerixafor in balancing cost-effectiveness and drug efficacy in MM treatment.

Prolonged Lenalidomide Induction Does Not Significantly Impair Stem Cell Collection in Multiple Myeloma Patients Mobilized With Cyclophosphamide or Plerixafor: A Report From The Covid Era.

INTRODUCTION: Induction therapy for multiple myeloma is traditionally capped at 6 cycles of lenalidomide due to concerns that longer treatment compromises the ability to collect sufficient stem cells for autologous stem cell transplantation (ASCT). However, during the COVID-19 pandemic, many of our patients received prolonged lenalidomide induction due to concerns about proceeding to ASCT. We investigated whether prolonged induction with lenalidomide affects the efficacy of stem cell collection among patients mobilized with cyclophosphamide and/or plerixafor. PATIENTS AND METHODS: This single center, retrospective study included patients who were treated with lenalidomide induction regimens, received mobilization with cyclophosphamide or plerixafor, and underwent apheresis in preparation for ASCT. 94 patients were included, 40 of whom received prolonged induction with >6 cycles of lenalidomide containing regimen. RESULTS: Patients who received prolonged induction were more likely to require >1 day of apheresis (38% vs. 15%; OR 3.45; P = .0154), and there was a significant correlation between the duration of lenalidomide treatment and the apheresis time required to collect sufficient cells for transplant (R2 = 0.06423, P = .0148). However, there was no significant difference between patients who received prolonged induction and those who did not with respect to CD34+ stem cell yields at completion of apheresis (9.99 vs. 10.46 cells/Kg, P = .5513) or on the first day of collection (8.29 vs. 9.59 cells/Kg, P = .1788). CONCLUSION: Among patients treated with >6 cycles of lenalidomide, mobilization augmented with cyclophosphamide and/or plerixafor will likely facilitate sufficient stem cell harvest to permit ASCT.

Impact of mobilization regimen on multiday collection of peripheral blood CD34+ cells by large volume leukapheresis.

BACKGROUND: The collection yield of hematopoietic progenitors cell (HPC) by leukapheresis is critical for a successful transplantation, which often requires multiday collections to achieve the collection goal. STUDY DESIGN AND METHODS: Collection procedures of 181 patients who underwent leukapheresis for more than 1 day were reviewed. Patients were separated into six groups based on the mobilization regimen: G-CSF on day 1 (D1) and day 2 (D2) (G-G); G-CSF on D1 and G-CSF and plerixafor on D2 (G-GP); G-CSF and plerixafor on day D1 and D2 (GP-GP); G-CSF and plerixafor on D1 and G-CSF on D2 (GP-G); chemotherapy and G-CSF on D1 and D2 (GC-GC); and chemotherapy, G-CSF, and plerixafor on D1 and D2 (GCP-GCP). Patient's pre-collection CD34 count (pre-CD34) on D1 and D2 were compared in the same individual and among groups. RESULTS: We found D2 pre-CD34 were significantly decreased in G-G, GP-G, and GP-GP groups and significantly increased in G-GP group (p < .001) using a repeated measures ANOVA analysis. D2 pre-CD34 remained at similar levels as D1 in GC-GC and GCP-GCP groups. A multiple regression analysis showed that the mobilization regimen was the only factor that significantly affected pre-CD34 D2/D1 ratio (p < .001). There was a significant difference in the pre-CD34 D2/D1 ratio (p < .001) among these six groups with the lowest in GP-G group (0.40 ± 0.45), and the highest in G-GP group (2.35 ± 0.36). DISCUSSION: Mobilization regimen has significant impact on pre-collection CD34 count. Apheresis facilities may change mobilizing drugs accordingly to achieve a specific HPC goal.

Is surgical myectomy challenged by emergence of novel drug therapy with mavacamten?

For 60 years, surgical myectomy has been the definitive treatment for symptomatic obstructive hypertrophic cardiomyopathy (HCM). Myectomy provides the opportunity to reverse heart failure symptoms in the vast majority of patient with low risk when performed in experienced centers and associated with extended longevity. More recently, a novel class of negative inotropic drug therapy with mavacamten has emerged offering expanded treatment options for obstructive HCM. In the recently completed phase III clinical trial, the EXPLORER-HCM about one-third of patients on mavacamten achieved the primary end-point of subjective symptomatic improvement and increased functional capacity assessed by peak VO2. Of note, outflow gradients persistent in 43% of patients on mavacamten and 50% with symptoms consistent with NYHA class II or greater. A subset of patients also experienced significant reversible systolic dysfunction. Therefore, it is timely to place into perspective the potential role of mavacamten in context of the established low risk: high benefit of surgical myectomy for treatment of heart failure.

Multiple Myeloma: Risk Adapted Use of Plerixafor for Stem Cell Mobilization Prior to Autologous Stem Cell Transplantation is Effective and Cost Efficient.

BACKGROUND: We used plerixafor in 'a risk adapted approach' for stem cell mobilization for multiple myeloma (MM) patients prior to autologous stem cell transplantation (ASCT). PATIENTS AND METHODS: Between January, 2017 and December, 2019 105 consecutive patients of MM were recruited (Study Cohort). Patients received inj G-CSF 10 µg/kg in 2 divided doses for 5 days. Day 4 peripheral blood (PB) CD34+ count was used as a guide; if count was < 20 cells/µl, patients received plerixafor. For those with ≥ 20 cells/µl apheresis was commenced on day 5. We compared their outcome with 156 MM patients transplanted between 2012 and 2016 with G-CSF mobilized PB stem cells (Control Cohort). Primary end point was to collect ≥2.0  ×  106 CD34+ cells/kg (minimal harvest). Secondary end points were: no of apheresis sessions, percentage of patients with optimal stem cell harvest (≥4.0  ×  106 CD34+ cells/kg) and cost analysis. An intent to treat analysis was done. RESULT: 96.2% of patients achieved ≥ 2.0  ×  106 CD34+ cells/kg in the study cohort vs. 87.2% in the control cohort, P < .01. Mean apheresis sessions were 1.5 vs. 1.7 respectively, P < .014 . Optimal stem cell harvest was 29.5% vs. 16%,P = .23. Days for neutrophil engraftment (P < 0.025) and for IV antibiotics (P < .0017) were favorable for the study cohort. Incremental cost effectiveness ratio was $ 15.80/- and $ 10.56/- per 1% increase to achieve a minimal and optimal harvest. CONCLUSION: Plerixafor in this risk adapted strategy resulted in successful mobilization, decreased time to engraftment and was cost effective.

Unearthing the Janus-face cholesterogenesis pathways in cancer.

Cholesterol biosynthesis, primarily associated with eukaryotes, occurs as an essential component of human metabolism with biosynthetic deregulation a factor in cancer viability. The segment that partitions between squalene and the C27-end cholesterol yields the main cholesterogenesis branch subdivided into the Bloch and Kandutsch-Russell pathways. Their importance in cell viability, in normal growth and development originates primarily from the amphipathic property and shape of the cholesterol molecule which makes it suitable as a membrane insert. Cholesterol can also convert to variant oxygenated product metabolites of distinct function producing a complex interplay between cholesterol synthesis and overall steroidogenesis. In this review, we disassociate the two sides of cholesterogenesisis affecting the type and amounts of systemic sterols-one which is beneficial to human welfare while the other dysfunctional leading to misery and disease that could result in premature death. Our focus here is first to examine the cholesterol biosynthetic genes, enzymes, and order of biosynthetic intermediates in human cholesterogenesis pathways, then compare the effect of proximal and distal inhibitors of cholesterol biosynthesis against normal and cancer cell growth and metabolism. Collectively, the inhibitor studies of druggable enzymes and specific biosynthetic steps, suggest a potential role of disrupted cholesterol biosynthesis, in coordination with imported cholesterol, as a factor in cancer development and as discussed some of these inhibitors have chemotherapeutic implications.

Successful "on-demand" plerixafor for autologous peripheral blood stem-cells transplantation for relapsed/refractory germ cell tumors.

BACKGROUND: Germ cell tumors represent, among solid cancers, a potentially curable disease even if up to 20% to 30% of patients (pts) relapse after first-line treatment especially considering intermediate and poor prognosis groups. In this scenario, patients are candidates for high-dose chemotherapy and autologous stem-cells transplantation as second-line treatment even though stem-cells mobilization potential can be affected by several cycles and regimens of chemotherapy. To date, plerixafor is authorized in poor mobilizer adult pts diagnosed with lymphoma or multiple myeloma and in pediatric solid tumors or lymphoma. Therefore, the use of plerixafor in adult pts with relapsing/refractory GCT is still off label. MATERIALS AND METHODS: In our study, we describe mobilization and collection of peripheral blood stem cells for 10 pts with germ cell tumors. Six patients underwent plerixafor administration since classified as poor mobilizers based on WBC count (>5.000/µL) and CD34+ cell count (<15/µL) the day before apheresis procedure. RESULTS: On the first day of apheresis, plerixafor administration in poor mobilizers made possible a remarkable boost of CD34+ cells in such a way to overlap that of good mobilizers' (32/µL vs 35/µL, respectively, P > .05). CONCLUSION: Therefore, in our experience, plerixafor made a good fraction of poor mobilizer patients eligible for mobilization and collection and able to undergo the predicted autologous stem-cells transplantation; thus, the lack of access to the use of plerixafor in this setting of patients risks jeopardizing an effective treatment, especially in case of poor prognosis.

Subacute AMD3100 Treatment Is Not Efficient in Neonatal Hypoxic-Ischemic Rats.

BACKGROUND AND PURPOSE: Despite the advances in treating neonatal hypoxic-ischemic encephalopathy (HIE) with induced hypothermia, the rates of severe disability are still high among survivors. Preclinical studies have indicated that cell therapies with hematopoietic stem/progenitor cells could improve neurological outcomes in HIE. In this study, we investigated whether the administration of AMD3100, a CXCR4 antagonist that mobilizes hematopoietic stem/progenitor cells into the circulation, has therapeutic effects in HIE. METHODS: P10 Wistar rats of both sexes were subjected to right common carotid artery occlusion or sham procedure, and then were exposed to hypoxia for 120 minutes. Two subcutaneous injections of AMD3100 or vehicle were given on the third and fourth day after HIE. We first assessed the interindividual variability in brain atrophy after experimental HIE and vehicle treatment in a small cohort of rats. Based on this exploratory analysis, we designed and conducted an experiment to test the efficacy of AMD3100. Brain atrophy on day 21 after HIE was defined as the primary end point. Secondary efficacy end points were cognitive (T-water maze) and motor function (rotarod) on days 17 and 18 after HIE, respectively. RESULTS: AMD3100 did not decrease the brain atrophy in animals of either sex. Cognitive impairments were not observed in the T-water maze, but male hypoxic-ischemic animals exhibited motor coordination deficits on the rotarod, which were not improved by AMD3100. A separate analysis combining data from animals of both sexes also revealed no evidence of the effectiveness of AMD3100 treatment. CONCLUSIONS: These results indicate that the subacute treatment with AMD3100 does not improve structural and functional outcomes in a rat HIE model.

Effect of Mavacamten on Echocardiographic Features in Symptomatic Patients With Obstructive Hypertrophic Cardiomyopathy.

BACKGROUND: EXPLORER-HCM (Clinical Study to Evaluate Mavacamten [MYK-461] in Adults With Symptomatic Obstructive Hypertrophic Cardiomyopathy) demonstrated that mavacamten, a cardiac myosin inhibitor, improves symptoms, exercise capacity, and left ventricular outflow tract (LVOT) obstruction in patients with obstructive hypertrophic cardiomyopathy (oHCM). OBJECTIVES: The purpose of this study was to evaluate mavacamten's effect on measures of cardiac structure and function and its association with changes in other clinical measures. METHODS: Key echocardiographic parameters from serial echocardiograms over 30 weeks from 251 symptomatic oHCM patients (mavacamten [n = 123], placebo [n = 128]) were assessed in a core laboratory. RESULTS: More patients on mavacamten (80.9%; n = 76 of 94) vs placebo (34.0%; n = 33 of 97) showed complete resolution of mitral valve systolic anterior motion after 30 weeks (difference, 46.8%; P < 0.0001). Mavacamten also improved measures of diastolic function vs placebo, including left atrial volume index (LAVI) (mean ± SD baseline: 40 ± 12 mL/m2 vs 41 ± 14 mL/m2; mean change from baseline of -7.5 mL/m2 [95% CI: -9.0 to -6.1 mL/m2] vs -0.09 mL/m2 [95% CI: -1.6 to 1.5 mL/m2]; P < 0.0001) and lateral E/e' (baseline, 15 ± 6 vs 15 ± 8; change of -3.8 [95% CI: -4.7 to -2.8] vs 0.04 [95% CI: -0.9 to 1.0]; P < 0.0001). Among mavacamten-treated patients, improvement in resting, Valsalva, and post-exercise LVOT gradients, LAVI, and lateral E/e' was associated with reduction in N-terminal pro-B-type natriuretic peptide (P ≤ 0.03 for all). Reduction in LAVI was associated with improved peak exercise oxygen consumption (P = 0.04). CONCLUSIONS: Mavacamten significantly improved measures of left ventricular diastolic function and systolic anterior motion. Improvement in LVOT obstruction, LAVI, and E/e' was associated with reduction in a biomarker of myocardial wall stress (N-terminal pro-B-type natriuretic peptide). These findings demonstrate improvement in important markers of the pathophysiology of oHCM with mavacamten. (Clinical Study to Evaluate Mavacamten [MYK-461] in Adults With Symptomatic Obstructive Hypertrophic Cardiomyopathy; NCT03470545).

Posttransplant blockade of CXCR4 improves leukemia complete remission rates and donor stem cell engraftment without aggravating GVHD.

Allogeneic hematopoietic cell transplantation (allo-HCT) is a promising therapeutic option for hematological malignancies, but relapse resulting predominantly from residual disease in the bone marrow (BM) remains the major cause of treatment failure. Using immunodeficient mice grafted with laboratory-generated human B-ALL, our previous study suggested that leukemia cells within the BM are resistant to graft-versus-leukemia (GVL) effects and that mobilization with CXCR4 antagonists may dislodge leukemia cells from the BM, enabling them to be destroyed by GVL effects. In this study, we extended this approach to patient-derived xenograft (PDX) and murine T-ALL and AML models to determine its clinical relevance and effects on GVHD and donor hematopoietic engraftment. We found that posttransplant treatment with the CXCR4 antagonist AMD3100 significantly improved the eradication of leukemia cells in the BM in PDX mice grafted with B-ALL cells from multiple patients. AMD3100 also significantly improved GVL effects in murine T-ALL and AML models and promoted donor hematopoietic engraftment in mice following nonmyeloablative allo-HCT. Furthermore, posttransplant treatment with AMD3100 had no detectable deleterious effect related to acute or chronic GVHD. These findings provide important preclinical data supporting the initiation of clinical trials exploring combination therapy with CXCR4 antagonists and allo-HCT.

Single-center results reporting improved hematopoietic stem cell mobilization success in pediatric and young adult patients with solid tumors and lymphoma.

BACKGROUND: High-dose chemotherapy with autologous hematopoietic stem cell transplantation (auto-HSCT) is an established treatment for pediatric and young adult patients with solid tumors and lymphomas. Plerixafor is a CXC chemokine receptor type 4 (CXCR4) antagonist that can be used with granulocyte colony stimulating factor (G-CSF) to amplify the mobilization of hematopoietic stem cells (HSCs). METHODS: We performed a retrospective analysis of 167 pediatric solid tumor and lymphoma patients from January 2010 to July 2020 in whom HSCs were mobilized using G-CSF alone or with plerixafor. RESULTS: Thirteen heavily pretreated patients (33.3%) required twice-daily dosing of G-CSF compared to five patients (3.9%) in the not heavily pretreated group (p = .0005). Fourteen heavily pretreated patients (35.9%) required plerixafor compared to four patients (3.1%) in the comparison cohort (p = .0002). The number of mobilization days was similar between both cohorts, with 5 days (range 3-11 days) in the heavily pretreated group and 5 days (range 3-13 days) in the not heavily pretreated group (p = .55). The number of harvest days was 2 days (range 1-5 days) in the heavily pretreated group and 1 day (range 1-4 days) in the not heavily pretreated group (p = .0025). The final cluster of differentiation (CD)34+ /kilogram (kg) count was 9.52 × 106 /kg among heavily pretreated patients compared to 34.99 × 106 /kg CD34+ cells in the comparison group (p < .0001). Three heavily pretreated patients (7.7%) failed HSC mobilization. CONCLUSIONS: Patients at the highest risk for poor HSC mobilization can be successfully treated with more frequent G-CSF dosing or G-CSF with plerixafor in a large majority of cases.

Direct detection of the myosin super-relaxed state and interacting-heads motif in solution.

The interacting-heads motif (IHM) is a structure of myosin that has been proposed to modulate cardiac output by occluding myosin molecules from undergoing the force-generating cycle. It is hypothesized to be the structural basis for the super-relaxed state (SRX), a low-ATPase kinetic state thought to be cardioprotective. The goal of the present study was to test this hypothesis by determining directly and quantitatively the fractions of myosin in the IHM and SRX under the same conditions in solution. To detect the structural IHM, we used time-resolved fluorescence resonance energy transfer to quantitate two distinct populations. One population was observed at a center distance of 2.0 nm, whereas the other was not detectable by fluorescence resonance energy transfer, implying a distance greater than 4 nm. We confirmed the IHM assignment to the 2.0-nm population by applying the same cross-linking protocol used previously to image the IHM by electron microscopy. Under the same conditions, we also measured the fraction of myosin in the SRX using stopped-flow kinetics. Our results show that the populations of SRX and IHM myosin were similar, unless treated with mavacamten, a drug that recently completed phase III clinical trials to treat hypertrophic cardiomyopathy and is proposed to act by stabilizing both the SRX and IHM. However, we found that mavacamten had a much greater effect on the SRX (55% increase) than on the IHM (4% increase). We conclude that the IHM structure is sufficient but not necessary to produce the SRX kinetic state.

Addition of plerixafor for mobilization of stem cells with bortezomib is feasible in dialysis-dependent multiple myeloma.

Plerixafor and bortezomib have recently been used in autologous stem cell collection to increase the amount of stem cells collected. However, no reports have described the combined use of plerixafor and bortezomib in cases of dialysis-dependent multiple myeloma. The dialysis-dependent multiple myeloma patient in the present study had a small amount of CD34-positive cells with plerixafor and filgrastim, and also with bortezomib and cyclophosphamide. However, by adding plerixafor to bortezomib and cyclophosphamide, collected CD34-positive cells were increased six-fold compared to the previous day. These findings suggest that the combination of plerixafor and bortezomib may be effective in those patients.

Latest update on chemokine receptors as therapeutic targets.

The chemokine system plays a fundamental role in a diverse range of physiological processes, such as homeostasis and immune responses. Dysregulation in the chemokine system has been linked to inflammatory diseases and cancer, which renders chemokine receptors to be considered as therapeutic targets. In the past two decades, around 45 drugs targeting chemokine receptors have been developed, yet only three are clinically approved. The challenging factors include the limited understanding of aberrant chemokine signalling in malignant diseases, high redundancy of the chemokine system, differences between cell types and non-specific binding of the chemokine receptor antagonists due to the broad ligand-binding pockets. In recent years, emerging studies attempt to characterise the chemokine ligand-receptor interactions and the downstream signalling protein-protein interactions, aiming to fine tuning to the promiscuous interplay of the chemokine system for the development of precision medicine. This review will outline the updates on the mechanistic insights in the chemokine system and propose some potential strategies in the future development of targeted therapy.

Role of CXCR4 in the progression and therapy of acute leukaemia.

CXCR4 is expressed on leukaemia cells and haematopoietic stem cells (HSCs), and its ligand stromal-derived factor 1 (SDF-1) is produced abundantly by stromal cells in the bone marrow (BM). The SDF-1/CXCR4 axis plays important roles in homing to and retention in the protective BM microenvironment of malignant leukaemia cells and normal HSCs. CXCR4 expression is regulated by multiple mechanisms and the level of CXCR4 expression on leukaemia cells has prognostic indications in patients with acute leukaemia. CXCR4 antagonists can mobilize leukaemia cells from BM to circulation, which render them effectively eradicated by chemotherapeutic agents, small molecular inhibitors or hypomethylating agents. Therefore, such combinational therapies have been tested in clinical trials. However, new evidence emerged that drug-resistant leukaemia cells were not affected by CXCR4 antagonists, and the migration of certain leukaemia cells to the leukaemia niche was independent of SDF-1/CXCR4 axis. In this review, we summarize the role of CXCR4 in progression and treatment of acute leukaemia, with a focus on the potential of CXCR4 as a therapeutic target for acute leukaemia. We also discuss the potential value of using CXCR4 antagonists as chemosensitizer for conditioning regimens and immunosensitizer for graft-vs-leukaemia effects of allogeneic haematopoietic stem cell transplantation.

Engraftment after autologous hematopoietic stem cell transplantation in patients mobilized with Plerixafor: A retrospective, multicenter study of a large series of patients.

Plerixafor (PLX) appears to effectively enhance hematopoietic stem-cell mobilization prior to autologous hematopoietic stem cell transplantation (auto-HCT). However, the quality of engraftment following auto-HCT has been little explored. Here, engraftment following auto-HCT was assessed in patients mobilized with PLX through a retrospective, multicenter study of 285 consecutive patients. Information on early and 100-day post-transplant engraftment was gathered from the 245 patients that underwent auto-HCT. The median number of PLX days to reach the stem cell collection goal (≥2 × 106 CD34+ cells/kg) was 1 (range 1-4) and the median PLX administration time before apheresis was 11 h (range 1-18). The median number of apheresis sessions to achieve the collection goal was 2 (range 1-5) and the mean number of CD34+ cells collected was 2.95 × 106/kg (range 0-30.5). PLX administration was safe, with only 2 mild and transient gastrointestinal adverse events reported. The median time to achieve an absolute neutrophil count (ANC) >500/µL was 11 days (range 3-31) and the median time to platelet recovery >20 × 103/µL was 13 days (range 5-69). At 100 days after auto-HCT, the platelet count was 137 × 109/L (range 7-340), the ANC was 2.3 × 109/L (range 0.1-13.0), and the hemoglobin concentration was 123 g/L (range 79-165). PLX use allowed auto-HCT to be performed in a high percentage of poorly mobilized patients, resulting in optimal medium-term engraftment in the majority of patients in whom mobilization failed, in this case mainly due to suboptimal peripheral blood CD34+ cell concentration on day +4 or low CD34+ cell yield on apheresis.

Acetylation of KLF5 maintains EMT and tumorigenicity to cause chemoresistant bone metastasis in prostate cancer.

Advanced prostate cancer (PCa) often develops bone metastasis, for which therapies are very limited and the underlying mechanisms are poorly understood. We report that bone-borne TGF-ß induces the acetylation of transcription factor KLF5 in PCa bone metastases, and acetylated KLF5 (Ac-KLF5) causes osteoclastogenesis and bone metastatic lesions by activating CXCR4, which leads to IL-11 secretion, and stimulating SHH/IL-6 paracrine signaling. While essential for maintaining the mesenchymal phenotype and tumorigenicity, Ac-KLF5 also causes resistance to docetaxel in tumors and bone metastases, which is overcome by targeting CXCR4 with FDA-approved plerixafor. Establishing a mechanism for bone metastasis and chemoresistance in PCa, these findings provide a rationale for treating chemoresistant bone metastasis of PCa with inhibitors of Ac-KLF5/CXCR4 signaling.