Safety and Efficacy of Prophylactic Levofloxacin in Pediatric and Adult Hematopoietic Stem Cell Transplantation Patients

Antibiotic Prophylaxis During Allogeneic Stem Cell transplantation-A Comprehensive Single Center Retrospective Analysis

BACKGROUND

Prophylactic antibiotics are still controversial during allogeneic hematopoietic stem cell transplantation (allo-HSCT). In our transplant center, we suspended antibiotic prophylaxis during allo-HSCT in 2017.

OBJECTIVE

The main objective of this study was the detailed analysis of the potentially beneficial impact of omittance of standard antibiotic prophylaxis during allo-HSCT in survival and Graft-versus-Host disease (GvHD) development, especially with consideration of confounding factors and competing events. Secondary objectives were the evaluation of the risk of severe infections and transplant-related mortality without antibiotic prophylaxis, the detailed assessment of bacterial and viral infections including multiresistant pathogens as well as occurrence of relapse in both groups. This study aims to support the development of future antibiotic strategies in allo-HSCT.

STUDY DESIGN

We retrospectively analyzed patient outcome in the time periods before (between December 2012 and February 2017) and after suspension (between March 2017 and June 2020) of antibiotic prophylaxis during allo-HSCT. Relevant clinical outcome parameters of the patients (n = 221) were collected by chart-review in the two groups (with antibiotic prophylaxis n = 101 versus without antibiotic prophylaxis n = 120). All patients were 18 years or older. Propensity score methods were used to adjust for potentially confounding patient characteristics. To address competing events, transitions between moderate/severe acute and chronic GvHD, relapse and death were analyzed using an inverse-propensity score weighted multistate modeling approach.

RESULTS

While we observed a trend towards an improved outcome in the cohort without antibiotic prophylaxis, the inverse-propensity-score-weighted analyses did not show significant differences between the two groups in overall survival (OS) (P = .811) or development of acute GvHD (aGvHD) grade 3/4 (P = .158) and chronic moderate/severe GvHD (cGvHD) (P = .686). Multistate analysis respecting competing events revealed comparable estimated probabilities without antibiotic prophylaxis versus with antibiotic prophylaxis in OS (35.0% [95% CI: 28.2%-42.7%] versus 35.3% [95% CI: 27.8%-41.1%]) as well as development of aGvHD grade 3/4 (7.7% [95% CI: 5.9%-12.2%] vs. 10.6% [95% CI: 7.7%-15.7%]) and moderate/severe cGvHD (21.0% [95% CI: 17.7%-30.0%] vs. 23.8% [95% CI: 19.6%-31.4%]). Similar analyses showed also no significant differences in relapse rate, transplant-related mortality, relapse-related mortality, or GvHD-free/relapse-free survival between the two groups. An observed increase in severe infections without antibiotic prophylaxis did not lead to a significantly higher mortality rate. Viral reactivation and detection of multiresistant bacteria were comparable, yet a higher incidence of Clostridioides difficile infections was observed in patients receiving antibiotic prophylaxis.

CONCLUSION

Our study supports previous reports of noninferiority of allo-HSCT without use of antibiotic prophylaxis with close monitoring and rapid intervention, if infection is suspected. The trend towards improved outcomes without antibiotic prophylaxis, however, might not only be due to the absence of antibiotic prophylaxis but also due to additional progresses in the field over the recent years. While the present study is too small to draw definite conclusions, these results strongly warrant further multicenter studies addressing the potential benefit of omitting antibiotic prophylaxis during allo-HSCT.

Fluoroquinolone Prophylaxis in Children With Cancer: A Pro/Con Discussion

There are conflicting recommendations on whether to use or not to use fluoroquinolone prophylaxis in pediatric oncology patients. An international pediatric clinical practice guideline (CPG) recommends administering levofloxacin prophylaxis in patients with acute myeloblastic leukemia and relapsed acute lymphoblastic leukemia receiving intensive chemotherapy as this practice has been found to reduce episodes of fever and bacteremia. A separate European CPG does not recommend levofloxacin prophylaxis because of concerns for adverse effects, including potentiation of fluoroquinolone resistance and possible increased resistance to other classes of antibiotics. The nuance of the decision to give or not give prophylaxis is discussed in the context of published evidence defining the risks and benefits of levofloxacin prophylaxis for pediatric leukemia patients at high risk for bacterial infection. Knowledge gaps are also identified to guide further investigations to optimize the use of fluoroquinolone prophylaxis in pediatric patients receiving chemotherapy for cancer or undergoing a hematopoietic cell transplantation.

Levofloxacin prophylaxis in pediatric oncology and hematopoietic stem cell transplantation: a literature review

Bloodstream infections (BSI) are one of the leading causes of morbidity and mortality in children and young adults receiving chemotherapy for malignancy or undergoing hematopoietic stem cell transplantation (HSCT). Antibiotic prophylaxis is commonly used to decrease the risk of BSI; however, antibiotics carry an inherent risk of complications. The aim of this manuscript is to review levofloxacin prophylaxis in pediatric oncology patients and HSCT recipients. We reviewed published literature on levofloxacin prophylaxis to prevent BSI in pediatric oncology patients and HSCT recipients. Nine manuscripts were identified. The use of levofloxacin is indicated in neutropenic children and young adults receiving intensive chemotherapy for leukemia or undergoing HSCT. These results support the efficacy of levofloxacin in pediatric patients with leukemia receiving intensive chemotherapy and should be considered in pediatric patients undergoing HSCT prior to engraftment.

Stopping antibacterial prophylaxis in pediatric allogeneic hematopoietic cell transplantation: An internal audit

BACKGROUND

Antibacterial prophylaxis in children and adolescents undergoing allogeneic hematopoietic cell transplantation (HCT) is controversial and not recommended by international guidelines. We analyzed relevant posttransplant outcomes following discontinuation of antibacterial prophylaxis at a major European pediatric transplant center.

METHODS

The single-center retrospective audit included all pediatric allogeneic HCT patients (pts) transplanted between 2011 and 2020 before (≤2014) and after (≥2015) stopping routine antibacterial prophylaxis with penicillin, metronidazole, and ciprofloxacin upon start of the conditioning regimen. The primary endpoint was overall survival until the first hospital discharge. Secondary endpoints included the occurrence of fever; bacterial infections; and cumulative days with antibacterial agents until discharge.

RESULTS

A total of 257 HCT procedures were performed in 249 pts (median age: 10 years, range, 0.2-22.5) for leukemia/lymphoma (n = 150) and nonmalignant disorders (n = 107). Of these, 104 procedures were performed before (cohort 1) and 153 after (cohort 2) stopping prophylaxis. Overall survival until discharge was 90.4% in cohort 1 and 96.1% in cohort 2 (p = .06). No differences were observed in the occurrence of fever (92.3 vs. 94.1%; p = .57) and bacterial infections (34.6 vs. 25.5%; p = .11). The median number of days on antibacterial agents was significantly lower in cohort 2 (39 vs. 34; p = .002). Detection rates of resistant organisms were overall low.

CONCLUSION

In this single-center audit, the stop of routine antibacterial prophylaxis had no effect on the occurrence of fever, bacterial infections, resistant organisms, and GVHD. Overall antibiotic use was significantly reduced, and survival was noninferior to the historical control cohort.

Dual-Activity Fluoroquinolone-Transportan 10 Conjugates Offer Alternative Leukemia Therapy during Hematopoietic Cell Transplantation

Hematopoietic cell transplantation (HCT) is often considered a last resort leukemia treatment, fraught with limited success due to microbial infections, a leading cause of mortality in leukemia patients. To address this critical issue, we explored a novel approach by synthesizing antileukemic agents containing antibacterial substances. This innovative strategy involves conjugating fluoroquinolone antibiotics, such as ciprofloxacin (CIP) or levofloxacin (LVX), with the cell-penetrating peptide transportan 10 (TP10). Here, we demonstrate that the resultant compounds display promising biologic activities in preclinical studies. These novel conjugates not only exhibit potent antimicrobial effects but are also selective against leukemia cells. The cytotoxic mechanism involves rapid disruption of cell membrane asymmetry leading to membrane damage. Importantly, these conjugates penetrated mammalian cells, accumulating within the nuclear membrane without significant effect on cellular architecture or mitochondrial function. Molecular simulations elucidated the aggregation tendencies of TP10 conjugates within lipid bilayers, resulting in membrane disruption and permeabilization. Moreover, mass spectrometry analysis confirmed efficient reduction of disulfide bonds within TP10 conjugates, facilitating release and activation of the fluoroquinolone derivatives. Intriguingly, these compounds inhibited human topoisomerases, setting them apart from traditional fluoroquinolones. Remarkably, TP10 conjugates generated lower intracellular levels of reactive oxygen species compared with CIP and LVX. The combination of antibacterial and antileukemic properties, coupled with selective cytostatic effects and minimal toxicity toward healthy cells, positions TP10 derivatives as promising candidates for innovative therapeutic approaches in the context of antileukemic HCT. This study highlights their potential in search of more effective leukemia treatments. SIGNIFICANCE STATEMENT: Fluoroquinolones are commonly used antibiotics, while transportan 10 (TP10) is a cell-penetrating peptide (CPP) with anticancer properties. In HCT, microbial infections are the primary cause of illness and death. Combining TP10 with fluoroquinolones enhanced their effects on different cell types. The dual pharmacological action of these conjugates offers a promising proof-of-concept solution for leukemic patients undergoing HCT. Strategically designed therapeutics, incorporating CPPs with antibacterial properties, have the potential to reduce microbial infections in the treatment of malignancies.

Adverse effects of antibiotics in children with cancer: are short-course antibiotics for febrile neutropenia part of the solution?

INTRODUCTION

Febrile neutropenia is a common complication experienced by children with cancer or those undergoing hematopoietic stem cell transplantation. Repeated episodes of febrile neutropenia result in cumulative exposure to broad-spectrum antibiotics with potential for a range of serious adverse effects. Short-course antibiotics, even in patients with high-risk febrile neutropenia, may offer a solution.

AREAS COVERED

This review addresses the known broad effects of antibiotics, highlights developments in understanding the relationship between cancer, antibiotics, and the gut microbiome, and discusses emerging evidence regarding long-term adverse antibiotic effects. The authors consider available evidence to guide the duration of empiric antibiotics in pediatric febrile neutropenia and directions for future research.

EXPERT OPINION

Broad-spectrum antibiotics are associated with antimicrobial resistance, Clostridioides difficile infection, invasive candidiasis, significant disturbance of the gut microbiome and may seriously impact outcomes in children with cancer or undergoing allogenic hematopoietic stem cell transplant. Short-course empiric antibiotics are likely safe in most children with febrile neutropenia and present a valuable opportunity to reduce the risks of antibiotic exposure.

Levofloxacin prophylaxis and parenteral nutrition have a detrimental effect on intestinal microbial networks in pediatric patients undergoing HSCT

The gut microbiome (GM) has shown to influence hematopoietic stem cell transplantation (HSCT) outcome. Evidence on levofloxacin (LVX) prophylaxis usefulness before HSCT in pediatric patients is controversial and its impact on GM is poorly characterized. Post-HSCT parenteral nutrition (PN) is oftentimes the first-line nutritional support in the neutropenic phase, despite the emerging benefits of enteral nutrition (EN). In this exploratory work, we used a global-to-local networking approach to obtain a high-resolution longitudinal characterization of the GM in 30 pediatric HSCT patients receiving PN combined with LVX prophylaxis or PN alone or EN alone. By evaluating the network topology, we found that PN, especially preceded by LVX prophylaxis, resulted in a detrimental effect over the GM, with low modularity, poor cohesion, a shift in keystone species and the emergence of modules comprising several pathobionts, such as Klebsiella spp., [Ruminococcus] gnavus, Flavonifractor plautii and Enterococcus faecium. Our pilot findings on LVX prophylaxis and PN-related disruption of GM networks should be considered in patient management, to possibly facilitate prompt recovery/maintenance of a healthy and well-wired GM. However, the impact of LVX prophylaxis and nutritional support on short- to long-term post-HSCT clinical outcomes has yet to be elucidated.

Role of Gut Microbiota and Oxidative Stress in the Progression of Transplant-Related Complications following Hematopoietic Stem Cell Transplantation

Hematopoietic stem cell transplantation (HSCT), also known as bone marrow transplantation, has curative potential for various hematologic malignancies but is associated with risks such as graft-versus-host disease (GvHD), severe bloodstream infection, viral pneumonia, idiopathic pneumonia syndrome (IPS), lung fibrosis, and sinusoidal obstruction syndrome (SOS), which severely deteriorate clinical outcomes and limit the wide application of HSCT. Recent research has provided important insights into the effects of gut microbiota and oxidative stress (OS) on HSCT complications. Therefore, based on recent studies, we describe intestinal dysbiosis and OS in patients with HSCT and review recent molecular findings underlying the causal relationships of gut microbiota, OS, and transplant-related complications, focusing particularly on the involvement of gut microbiota-mediated OS in postengraftment complications. Also, we discuss the use of antioxidative and anti-inflammatory probiotics to manipulate gut microbiota and OS, which have been associated with promising effects in improving HSCT outcomes.

Effectiveness of Quinolone Prophylaxis in Pediatric Acute Leukemia and Hematopoietic Stem Cell Transplantation: A Systematic Review and Meta-analysis

The effectiveness of quinolone prophylaxis in high-risk hematological pediatric patients is controversial. A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, including studies that involved children and young adults undergoing chemotherapy for acute leukemia or hematopoietic stem cell transplantation (HSCT) who received quinolone prophylaxis compared with no prophylaxis. A meta-analysis was performed on bloodstream infections and neutropenic fever. Data regarding the impact of prophylaxis on overall survival, antibiotic exposure, antibiotic-related adverse effects, antibiotic resistance, Clostridium difficile infections, fungal infections, length of hospitalization, and costs were reviewed in the descriptive analysis. Sixteen studies were included in the qualitative analysis, and 10 of them met the criteria for quantitative analysis. Quinolone prophylaxis was effective in reducing the rate of bloodstream infections and neutropenic fever in pediatric acute leukemia compared with no prophylaxis, but it had no significant effect in HSCT recipients. Prophylaxis was associated with a higher rate of bacterial resistance to fluoroquinolones and higher antibiotic exposure.