Blockade of CD300A enhances the ability of human NK cells to lyse hematologic malignancies

Objective: The human cluster of differentiation(CD)300A, a type-I transmembrane protein with immunoreceptor tyrosine-based inhibitory motifs, was investigated as a potential immune checkpoint for human natural killer(NK) cells targeting hematologic malignancies(HMs).Methods: We implemented a stimulation system involving the CD300A ligand, phosphatidylserine(PS), exposed to the outer surface of malignant cells. Additionally, we utilized CD300A overexpression, a CD300A blocking system, and a xenotransplantation model to evaluate the impact of CD300A on NK cell efficacy against HMs in in vitro and in vivo settings. Furthermore, we explored the association between CD300A and HM progression in patients.Results: Our findings indicated that PS hampers the function of NK cells. Increased CD300A expression inhibited HM lysis by NK cells. CD300A overexpression shortened the survival of HM-xenografted mice by impairing transplanted NK cells. Blocking PS–CD300A signals with antibodies significantly amplified the expression of lysis function-related proteins and effector cytokines in NK cells, thereby augmenting the ability to lyse HMs. Clinically, heightened CD300A expression correlated with shorter survival and an “exhausted” phenotype of intratumoral NK cells in patients with HMs or solid tumors.Conclusions: These results propose CD300A as a potential target for invigorating NK cell-based treatments against HMs.

Prevention of hepatitis B reactivation in patients with hematologic malignancies treated with novel systemic therapies:Who and Why?

The risk of reactivation in patients with chronic or past/resolved hepatitis B virus(HBV)infection receiving chemotherapy or immunosuppressive drugs is a wellknown possibility.The indication of antiviral prophylaxis with nucleo(t)side analogue is given according to the risk of HBV reactivation of the prescribed therapy.Though the advent of new drugs is occurring in all the field of medicine,in the setting of hematologic malignancies the last few years have been characterized by several drug classes and innovative cellular treatment.As novel therapies,there are few data about the rate of HBV reactivation and the decision of starting or not an antiviral prophylaxis could be challenging.Moreover,patients are often treated with a combination of different drugs,so evaluating the actual role of these new therapies in increasing the risk of HBV reactivation is difficult.First results are now available,but further studies are still needed.Patients with chronic HBV infection[hepatitis B surface antigen(HBsAg)positive]are reasonably all treated.Past/resolved HBV patients(HBsAg negative)are the actual area of uncertainty where it could be difficult choosing between prophylaxis and pre-emptive strategy.

Preclinical evaluation of cyclophosphamide and fludarabine combined with CD19 CAR-T in the treatment of B-cell hematologic malignancies in vivo

Background:Chimeric antigen receptor T(CAR-T)cell therapy has achieved marked therapeutic success in ameliorating hematological malignancies.However,there is an extant void in the clinical guidelines concerning the most effective chemotherapy regimen prior to chimeric antigen receptor T(CAR-T)cell therapy,as well as the optimal timing for CAR-T cell infusion post-chemotherapy.Materials and Methods:We employed cell-derived tumor xenograft(CDX)murine models to delineate the optimal pre-conditioning chemotherapy regimen and timing for CAR-T cell treatment.Furthermore,transcriptome sequencing was implemented to identify the therapeutic targets and elucidate the underlying mechanisms governing the treatment regimen.Results:Our preclinical in vivo evaluation determined that a combination of cyclophosphamide and fludarabine,followed by the infusion of CD19 CAR-T cells five days subsequent to the chemotherapy,exerts the most efficacious therapeutic effect in B-cell hematological malignancies.Concurrently,RNA-seq data indicated that the therapeutic efficacy predominantly perturbs tumor cell metabolism,primarily through the inhibition of key mitochondrial targets,such as C-Jun Kinase enzyme(C-JUN).Conclusion:In summary,the present study offers critical clinical guidance and serves as an authoritative reference for the deployment of CD19 CAR-T cell therapy in the treatment of B-cell hematological malignancies.

Hematological Malignancies in Sickle Cell Disease Patients: Report of Four Cases in Togo and Literature Review

Background: Hemopathies were rarely observed in major sickle cell disease patients some thirty years ago, probably due to the high mortality rate among the latter as a result of progressive complications. Thanks to advances in the management of sickle cell disease, patients' life expectancy has increased considerably, exposing them more frequently to neoplasia, including hematological malignancies. The increased risk of leukemogenesis is multifactorial and linked to the pathophysiological mechanisms of the clinical manifestations of sickle cell disease. Study Setting: The clinical haematology department of campus teaching hospital and the paediatric onco-haematology unit of Sylvanus Olympio teaching hospital in Lomé were used as study settings. Observations: Four hematologic malignancies were collected in a cohort of 5847 major sickle cell syndromes. The median age of the patients was 31.25 years (extremes: 14 and 58 years) and they were predominantly female (sex ratio M/F = 0.25). Two were on background therapy with hydroxyurea. Among the four patients, there were two cases of acute lymphocytic leukemia, including ALL3 in a 58-year-old SS woman and T-ALL2 in a 12-year-old SC. Then, a case of lymphocytic lymphoma in a 20-year-old SS man was reported and finally a case of chronic myelocytic leukemia in a 33-year-old woman of Sβ+ thalassaemia phenotype. Conclusion: To further report this coexistence, it is therefore essential to systematically consider hematological malignancies during major sickle cell syndromes even if there are similarities in the symptomatology of these two serious pathological situations.

Predictive value of co-expression patterns of immune checkpoint molecules for clinical outcomes of hematological malignancies

Co-expression of immune checkpoint(IC)molecules can exacerbate T cell exhaustion in patients with hematological malignancies(HMs)and contribute to the immune escape of tumor cells,which is related to poor clinical outcome.It is worth establishing and optimizing an ideal prediction model based on the co-expression patterns of IC molecules to evaluate the immune status of HM patients and predict their clinical outcome.In this perspective,we summarize the co-expression patterns of IC molecules and their importance as biomarkers that predict the prognosis of patients with different HMs,providing new insights for designing dual IC blockades(ICBs).

Acute myelomonocytic leukemia and T-lymphoblastic lymphoma as simultaneous bilineage hematologic malignancy treated with decitabine:A case report

BACKGROUND Simultaneous bilineage hematologic malignancies are rare;however,several cases of acute myeloid leukemia(AML)and T-lymphoblastic lymphoma(T-LBL)cooccurrence have been reported.A standard treatment for simultaneous AML and T-LBL has not yet been established,and its prognosis is very poor.Further studies to develop standard treatments are required to increase patient survival rates.CASE SUMMARY A 69-year-old man complaining of pleuritic chest pain visited the emergency room.Computed tomography revealed multiple enlarged lymph nodes(LNs)in the neck and groin and pulmonary thromboembolism with pulmonary infarction.Furthermore,a peripheral blood smear performed due to leukocytosis revealed circulating blasts.Acute myelomonocytic leukemia(AMML)was diagnosed after bone marrow examination,and T-LBL positivity for terminal deoxynucleotidyl transferase,cluster of differentiation(CD)34,and CD4 was confirmed by cervical LN biopsy.Decitabine and dexamethasone were administered because he could not receive intensive chemotherapy due to poor performance status.Complete remission of AMML and T-LBL was achieved after 4 cycles of decitabine plus dexamethasone.CONCLUSION We report the therapeutic effect of decitabine,a hypomethylating agent(HMA),in patients with concurrent bilineage hematologic malignancies and suggest that further studies are required to evaluate the therapeutic effect of HMAs on both lymphoid and bilineage hematologic malignancies.

Continuous renal replacement therapy with oXiris®in patients with hematologically malignant septic shock:A retrospective study

BACKGROUND The mortality rate from septic shock in patients with hematological malignancies(HMs)remains significantly higher than that in patients without HMs.A longer resuscitation time would definitely be harmful because of the irreversibly immunocompromised status of the patients.Shortening the resuscitation time through continuous renal replacement therapy(CRRT)with oXiris^(■)would be an attractive strategy in managing such patients.AIM To explore the effects of CRRT and oXiris^(■)in shortening the resuscitation time and modifying the host response by reducing inflammation mediator levels.METHODS Forty-five patients with HM were diagnosed with septic shock and underwent CRRT between 2018 and 2022.Patients were divided into two groups based on the hemofilter used for CRRT(oXiris^(■)group,n=26;M150 group,n=19).We compared the number of days of negative and total fluid balance after 7 d of CRRT between the groups.The heart rate,norepinephrine dose,Sequential Organ Failure Assessment(SOFA)score,and blood lactic acid levels at different time points in the two groups were also compared.Blood levels of inflammatory mediators in the 26 patients in the oXiris^(■)group were measured to further infer the possible mechanism.RESULTS The average total fluid balance after 7 d of CRRT in the oXiris^(■)group was significantly lower than that of patients in the M150 hemofilter group.The SOFA scores of patients after CRRT with oXiris^(■)therapy were significantly lower than those before treatment on day 1(d1),d3 and d7 after CRRT;these parameters were also significantly lower than those of the control group on d7.The lac level after oXiris^(■)therapy was significantly lower than that before treatment on d3 and d7 after CRRT.There were no significant differences in the above parameters between the two groups at the other time points.In the oXiris^(■)group,procalcitonin levels decreased on d7,whereas interleukin-6 and tumor necrosis factor levels decreased significantly on d3 and d7 after treatment.CONCLUSION CRRT with oXiris^(■)hemofilter may improve hemodynamics by reducing inflammatory mediators and playing a role in shortening the resuscitation period and decreasing total fluid balance in the resuscitation phases.

Recent progresson nuclear export protein XPO1 inhibitor in the treatment of hematological malignancies

Most tumor suppressor and growth-regulating proteins are transported via the plasmic nuclear transporter exportin 1(XPO1).Many malignancies have excessive XPO1 expression,which is associated with disease progression and resistance to therapy.A novel class of anticancer medication called selective inhibitor of nuclear export(SINE)can down-regulate the levels of a number of antigenic proteins in the cytoplasm,activate tumor suppressor and other growth regulating proteins,and promote the nuclear retention and apoptosis of tumor cells.This article discusses the function of XPO1 in drug resistance and tumor development as well as the advancement of XPO1 inhibitor research for the treatment of hematological cancers.

Efficacy and Safety Assessment of Antifungal Sequential Therapy from Micafungin to Liposomal Amphotericin B for Antibiotics-Refractory Febrile Neutropenia in Patients with Hematologic Malignancies

Invasive fungal infections are a major challenging problem in the management of febrile neutropenia (FN) in patients with hematologic malignancies. Liposomal amphotericin B (L-AmB) or micafungin (MCFG) has been widely used as a first-line empirical antifungal therapy for suspected fungal infection in such patients. However, there are several issues in patients receiving these agents: drug related toxicities for L-AmB and breakthrough fungal infections for MCFG. In order to make the best use of these 2 agents, we conducted a prospective study of sequential therapy from MCFG to L-AmB, and evaluated the efficacy and safety of this strategy in FN patients with hematologic malignancies. A total of 18 patients were enrolled, and 11 patients who fulfilled the protocol defined criteria were evaluated. Underlying diseases consisted of acute leukemia (n = 9), non-Hodgkin lymphoma (n = 1), and myelodysplastic syndrome (n = 1). Treatment success was achieved in 8 patients (72.7%). Drug-related adverse events occurred in 8 patients (72.7%). All of those adverse events except one case were below grade 2. Three patients required discontinuation of L-AmB. Although our empirical antifungal sequential therapy seems to be encouraging for antibiotics-refractory FN in patients with hematologic malignancies, further investigation in large-scale studies is warranted.

Navigating the complex terrain of hepatitis B virus reactivation in the era of Bruton tyrosine kinase inhibitors

In this editorial,we offer a summary of the risk associated with hepatitis B reactivation(HBVr)in the setting of both solid and hematologic malignancies treated with Bruton tyrosine kinase(BTK)inhibitors,with insights derived from current studies.Furthermore,we emphasize the critical need for a framework regarding robust risk evaluation in patients undergoing such treatments.This framework is essential for identifying those at increased risk of HBVr,enabling healthcare providers to implement proactive measures to prevent reactivation and ensure the safe administration of BTK inhibitor therapy.

CAR T Cell Therapy for Hematological Malignancies

As a rapidly progressing field in oncology,the adoptive transfer of T cells that have been genetically modified with chimeric antigen receptors(CARs)has shown striking efficacy in the management of hematological malignancies and has been reported in a number of clinical trials.of note,CAR T cell therapy has shown extraordinary potential,especially in relapsed/refractory patients.However,there are still challenges regarding the further development of this strategy,spanning from engineering and manufacturing issues,to limited applications,to accompanying toxicities.In this review,we will summarize the general knowledge of this novel method,including receptor composition,applications,adverse events and challenges.Additionally,we will propose several comprehensive recommendations.

Characteristics of escape mutations from occult hepatitis B virus infected patients with hematological malignancies in South Egypt

AIM To investigate the prevalence and virological characteristics of occult hepatitis B virus(HBV) infections in patients with hematological malignancies in South Egypt.METHODS Serum samples were collected from 165 patients with hematological malignancies to monitor titers of HBV DNA, hepatitis B surface antigen(HBs Ag), and antibodies to HBV core(anti-HBc) and surface antigens. Serum samples negative for HBs Ag and positive for anti-HBc were subjected to nucleic acid extraction and HBV DNA detection by real-time polymerase chain reaction. DNA sequences spanning the S region were analyzed in cases with occult HBV infection. In vitro comparative study of constructed 1.24-fold wild type and S protein mutant HBV genotype D clones was further performed. RESULTS HBV DNA was detected in 23(42.6%) of 54 patients with hematological malignancies who were HBsA g negative, but anti-HBc positive, suggesting the presence of occult HBV infection. The complete HBV genome was retrieved from 6 occult HBV patients, and P120 T and S143 L were detected in 3 and 2 cases, respectively. Site directed mutagenesis was done to produce 1.24-fold genotype D clones with amino acid mutations T120 and L143. The in vitro analyses revealed that a lower level of extracellular HBsA g was detected by chemiluminescence enzyme immunoassay(CLEIA) with the clone containing T120 mutation, compared with the wild type or the clone with S143 L mutation despite the similar levels of extracellular and intracellular HBs Ag detected by Western blot. Southern blot experiments showed that the levels of intracellular HBV DNA were not different between these clones. CONCLUSION Occult HBV infection is common in patients with hematological malignancies and associated with P120 T and S143 L mutations. 120 T mutation impairs the detection of HBsA g by CLEIA.

Application of super-resolution fluorescence microscopy in hematologic malignancies

Hematologic malignancies are one of the most common malignant tumors caused by the clonal proliferation and differentiation of hematopoietic and lymphoid stem cells.The examination of bone marrow cells combined with immunodeficiency typing is of great significance to the diagnostic type,treatment and prognosis of hematologic malignancies.Super-resolution fluorescence microscopy(SRM)is a special kind of optical microscopy technology,which breaks the resolution limit and was awarded the Nobel Prize in Chemistry in 2014.With the development of SRM,many related technologies have been applied to the diagnosis and treatment of clinical diseases.It was reported that a major type of SRM technique,single molecule localization microscopy(SMLM),is more sensitive than flow cytometry(FC)in detecting cell membrane antigens'expression,thus enabling better chances in detecting antigens on hematopoietic cells than traditional analytic tools.Furthermore,SRM may be applied to clinical pathology and may guide precision medicine and personalized medicine for clone hematopoietic cell diseases.In this paper,we mainly discuss the application of SRM in clone hematological malignancies.

Multiplex Reverse Transcription-Polymerase Chain Reaction for Simultaneous Screening of 29 Chromosomal Translocation in Hematologic Malignancies

Multiplex reverse transcription-polymerase chain reaction （M-RT-PCR） has been proved to possess great clinical potential for simultaneous screening of 29 chromosomal translocations in acute leukemia. To evaluate the clinical value of M-RT-PCR in hematologic malignancies, bone marrow samples from 90 patients with various hematologic malignancies, including 25 acute myelogenous leukemia （AML）, 22 acute lymphoblastic leukemia （ALL）, 27 chronic myelogenous leukemia （CML）, 4 myeloproliferative diseases （MPD）, 3 chronic lymphoblastic leukemia （CLL）, 3 non-Hodgkin＇s lymphoma （NHL）, 3 myelodysplastic syndrome （MDS）, 2 multiple myeloma （MM） and 1 malignant histocytosis （MH） were subjected to both M-RT-PCR and chromosome karyotypic analysis. Some of cases were subjected to follow-up examination of M-RT-PCR during the period of clinical complete remission （CR） for detection of minimal residual leukemia. In our hand, 12 of 29 chromosomal translocation transcripts including TEL/PDGFR, DEK/CAN, MLL/AF6, AMLI/ETO, MLL/AF9, BCR/ABL, MLL/MLL, PML/RARα, TLS/ERG, E2A/HLF, EVⅡ and HOXⅡ were detected in 57 cases （63.3 %） of the 90 samples, which were in consistence with the results of karyotypic analysis. Furthermore, M-RT-PCR had also shown good clinical relevance when used as an approach to detect minimal residual leukemia. We concluded that M-RT-PCR could be used as an efficient and fast diagnostic tool not only in the initial diagnosis of hematologic malignancies but also in subsequent monitor of minimal residual leukemia.

Concurrent renal cell carcinoma and hematologic malignancies: Nine case reports

BACKGROUND The presence of renal cell carcinoma(RCC)and hematologic malignancies(HM)in the same patient is rarely observed.Three primary findings have been described in these patients,including male gender and lymphoid malignancy predominance,and the HM are usually diagnosed before or simultaneously with the RCC.There is a lack of evidence about clinical outcomes in this setting.We report the common characteristics of 9 patients diagnosed with concurrent RCC and HM and their clinical course and response to treatment.CASE SUMMARY Four(44%)patients were diagnosed with RCC prior to the HM,the diagnosis was simultaneous in 4(44%)patients,and 1(11%)patient was diagnosed with the HM prior to the RCC.No patients were treated with cytotoxic chemotherapy or radiation between the diagnosis of RCC and HM.Several unique features were seen in our case series,such as 3 simultaneous cancers in 1(11%)patient,a splenectomy leading to remission of diffuse large B cell lymphoma without the use of chemotherapy in 1(11%)patient,chemotherapy and rituximab for lymphoma resulting in a complete response in primary RCC in 1(11%)patient,and immunotherapy providing an excellent response for primary renal leiomyosarcoma in 1(11%)patient.CONCLUSION These findings highlight the potential role of immune system dysregulation in patients with the diagnosis of RCC and HM whereby the first malignancy predisposes to the second through an immunomodulatory effect.HM have the potential of being confused with lymph node metastasis from kidney cancer.Lymph node biopsy may be necessary at the time of initial diagnosis or in cases of mixed response to therapy.Long-term medical surveillance is warranted when a patient is diagnosed with RCC or HM.Clinicians should be aware of the higher prevalence of male gender and lymphoid malignancy with concurrent RCC and HM and that either of these conditions may be diagnosed first or they may be diagnosed simultaneously.

Combination of CRISPR/Cas9 System and CAR-T Cell Therapy:A New Era for Refractory and Relapsed Hematological Malignancies

Chimeric antigen receptor T(CAR-T)cell therapy is the novel treatment strategy for hematological malignancies such as acute lymphoblastic leukemia(ALL),lymphoma and multiple myeloma.However,treatment-related toxicities such as cytokine release syndrome(CRS)and immune effector cell-associated neurotoxicity syndrome(ICANS)have become significant hurdles to CAR-T treatment.Multiple strategies were established to alter the CAR structure on the genomic level to improve efficacy and reduce toxicities.Recently,the innovative gene-editing technology-clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated nuclease9(Cas9)system,which particularly exhibits preponderance in knock-in and knockout at specific sites,is widely utilized to manufacture CAR-T products.The application of CRISPR/Cas9 to CAR-T cell therapy has shown promising clinical results with minimal toxicity.In this review,we summarized the past achievements of CRISPR/Cas9 in CAR-T therapy and focused on the potential CAR-T targets.

TMTP1, a Novel Tumor-homing Peptide, Specifically Targets Hematological Malignancies and Their Metastases

TMTP1, a 5-amino acid peptide NVVRQ, obtained by using the flagella peptide library screening in our previous studies, can be used for the labeling of malignant in situ and metastatic lesions, and even micro-metastases. In this study, TMTP1 was assessed for its ability to specifically target the malignant hematopoietic cells and metastatic lesions of hematological malignancies. FITC-TMTP1 was chemically synthesized. Immunofluorescence assay and competitive test were carried out to determine the specific binding capacity of TMTPl to hematological malignant cell lines, including HL60, k562, SHI-1, Jurkat, Raji, El-4 and umbilical cord blood mononuclear cells. Mononuclear cells were isolated from the bone marrow of healthy subjects and patients with chronic myeloid leukemia. Then the cells were co-clutured with TMTP1 or scrambled peptides and the binding and affinity of TMTP1 peptide to the primary cells of hematological malignancies were flow cytometrically analyzed. The binding speci-ficity of TMTP1 to target hematological malignancies was measured in vivo by intravenous injection of FITC-conjugated TMTP1 into El-4 lymphoma-bearing mice. The results showed that TMTP1 specifi-cally bound to the cells of a series of hematological malignancies, including HL60, k562, Jurkat, Raji , El-4 and chronic myeloid leukemia primary cells but not to bone marrow mononuclear cells from healthy subjects. By contrast, TMTP1 could bind to the metastatic foci of lymphoma originating from the EL-4 cell line while the scrambled peptide failed to do so. Moreover, the occult metastases could be identified, with high specificity, by detecting FITC-TMTP1. We are led to conclude that TMTP1, as a novel tumor-homing peptide, can serve as a marker for primary malignant and metastatic lesions for the early diagnosis of hematological malignances and a carrier of anticancer drugs for cancer treatment.

Is the traditional Chinese medicine helpful for patients with hematologic malignant diseases? A meta-analysis of randomized controlled trials

AIM:To evaluate the efficacy of traditional Chinese medicine(TCM)for the treatment of hematologic malignant diseases.METHODS:We searched the Cochrane CENTRAL,PubM ed,Embase,Web of Science,AMED,CNKI,Wanfang Platform;China Sinomed and the clinical trial registry web sites and Googlescholar electronically up to June19th,2014 and hand searched related publications.Only randomized controlled trials(RCTs)researching on whether TCM as the adjuvant treatment improved the effect for hematologic malignant diseases were included.Two reviewers extracted data and evaluated the studies independently.Pooled risk ratios(RR)were calculated as outcome measures.Our primary outcomes were the overall response(OR)rate.RESULTS:We retrieved 13143 references and included11 RCTs involved 891 participants after screening.Because the non-significant heterogeneity we used the fixed effect model to combine data and TCM had a significantly higher OR and CR(complete response)rates than the control[RR=1.17,95%CI:(1.10,1.25),P<0.00001;RR=1.24,95%CI:(1.11,1.37),P<0.0001,respectively].Only three studies included in the survival rate analysis.We combined them with random effects model and there was no significant difference between the TCM and control arms.Becauseof the low heterogeneity we used the fixed effect model to combine the non-hematologic adverse effects(AEs)data.Our results showed that TCM significantly decreased non-hematologic AEs rates we researched,the gastrointestinal reaction[RR=0.50,95%CI:(0.37,0.68),P<0.0001],liver and/or kidney injury[RR=0.37,95%CI:(0.26,0.53),P<0.00001]and heart injury[RR=0.24,95%CI:(0.09,0.68),P=0.007].Additionally,TCM had a trend to decrease the infection rate[RR=0.16,(0.02,1.12),P=0.07],but not statistically significantly.CONCLUSION:TCM increases OR and CR rates for hematologic malignances and reduces treatment associated serious non-hematologic AEs.Therefore,TCM should be included in the treatment of hematologic malignances.

A Prospective Study on HGV Infection after Transfusion in Pediatric Hematological Children

In order to delineate the infectious status of HGV in pediatric hemato-logical patients and its clinical features, 38 children were studied for HGV by reverse transcription nested polymerase chain reaction (RT-nPCR). The overall positive rate was 23. 68 %; the positive rate in 1-10 time transfusion recipients (mean 3. 26 times) was 3. 70 % while in over 10 time transfusion recipients (mean 20. 09 times) was 72. 73 %. A statistically significant difference was found between the two groups (P<0. 001). All HGV positive children showed diminished immunity and most were single HGV infection with no clinical and biochemical evidences of acute hepatitis. Our results suggest that HGV is one of the main causes of post-transfusion hepatic virus infection and the prevalence is related to transfusion times. Hematological malignancy maybe the most susceptible confluence of HGV.

Garenoxacin Prophylaxis for Febrile Neutropenia after Chemotherapy in Hematological Malignancies

Background: Febrile neutropenia is one of the most serious adverse events in patients with hematological malignancies and chemotherapy. The routine use of fluoroquinolone prophylaxis in patients with hematological malignancies is controversial. Therefore, we prospectively evaluated the efficacy and safety of prophylactic use of garenoxacin for febrile neutropenia. Patients and Methods: Consecutive adult patients with hematological malignancies who were at risk for chemotherapy-induced neutropenia lasting more than seven days were eligible for present study. They received oral garenoxacin (400 mg daily) from the neutrophil count decreased to less than 1000/μl and continued until the neutropenia had resolved. The primary endpoint was incidence of febrile neutropenia, and the secondary endpoints were the type and incidence of adverse events. Results: We enrolled 46 consecutive patients (median age, 59 years). The underlying diseases comprised acute myeloid leukemia (n = 17), acute lymphoblastic leukemia (n = 3), malignant lymphoma (n = 23), and multiple myeloma (n = 3). There were 23 febrile neutropenia episodes and 2 episodes of bacteremia. There were no grade 3 or 4 adverse events;however serum creatinine levels were significantly elevated after garenoxacin administration. The overall prophylactic efficacy of garenoxacin was 50%, and there were no infection-related deaths. Conclusions: Prophylactic use of garenoxacin is effective and safe in patients with hematological malignancies. (Clinical trial registration number: UMIN000004979).