Efficacy and safety of linezolid in immunocompromised children with cancer

Safety and clinical efficacy of linezolid in children: a systematic review and meta-analysis

BACKGROUND

We aimed to evaluate the tolerability and efficacy of linezolid in children for treating suspected and diagnosed Gram-positive bacterial infections.

METHODS

A systematic literature search was conducted up to April 23, 2021, using linezolid and its synonyms as search terms. Two reviewers independently identified and extracted relevant randomized controlled trials and prospective cohort studies. The extracted studies were included in a single-rate meta-analysis of adverse events and clinical outcomes using random-effects models.

RESULTS

A total of 1082 articles were identified, and nine studies involving 758 children were included in the meta-analysis. The overall proportion of adverse events was 8.91% [95% confidence interval (CI) = 1.64%-36.52%], with diarrhea (2.24%), vomiting (2.05%), and rash (1.72%) being the most common. The incidences of thrombocytopenia and anemia were 0.68% and 0.16%, respectively. Some specific adverse events, including rash and gastrointestinal events, were more frequent in the oral administration subgroup. In terms of efficacy, the overall proportion of clinical improvement was 88.80% (95% CI = 81.31%-93.52%). Children with a history of specific bacteriological diagnosis or concomitant antibiotic therapy had a 1.13-fold higher clinical improvement than children without such histories. The proportion of microbial eradication was 92.68% (95% CI = 84.66%-96.68%). The proportion of all-cause mortality was 0.16% (95% CI = 0.00%-7.75%).

CONCLUSIONS

Linezolid was well-tolerated in pediatric patients and was associated with a low frequency of adverse events, such as anemia, thrombocytopenia, and neutropenia. Moreover, linezolid was effective in children with diagnosed and suspected Gram-positive infections.

Therapeutic Options and Outcomes for the Treatment of Children with Gram-Positive Bacteria with Resistances of Concern: A Systematic Review

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant coagulase-negative Staphylococci (MR-CoNS), and vancomycin-resistant Enterococci (VRE) are increasing worldwide and represent a threat for the limited treatment options in pediatric patients and neonates compared to adults. Recommendations in pediatrics are mainly extrapolated from adults' studies.

METHODS

A literature search for the treatment of these pathogens in children (<18 years old) was conducted in Embase, MEDLINE, and Cochrane Library. Studies reporting data on single-patient-level outcomes related to a specific antibiotic treatment for multidrug resistant (MDR) Gram-positive bacterial infection in children were included. Studies reporting data from adults and children were included if single-pediatric-level information could be identified (PROSPERO registration: CRD42022383867).

RESULTS

The search identified 11,740 studies (since January 2000), of which 48 fulfilled both the inclusion and the exclusion criteria and were included in the analysis: 29 for MRSA, 20 for VRE, and seven for MR-CoNS. Most studies were retrospective studies. Vancomycin was mainly used as a comparator, while linezolid and daptomycin were the most studied antimicrobials showing good efficacy.

CONCLUSIONS

Linezolid showed a safety and efficacy profile in a neonatal setting; daptomycin is increasingly used for MRSA, but the evidence is scarce for VRE.

A systematic review and meta-analysis of myelosuppression in pediatric patients treated with linezolid for Gram-positive bacterial infections

BACKGROUND

The incidence of linezolid-induced myelosuppression in pediatric patients was reported at large difference among prospective studies, with a range of 0-24%. Additionally, there is little study which evaluated the impact of linezolid administration period on myelosuppression in pediatric patients, while it is one of the most frequent reason that linezolid therapy has to be discontinued in adult patients. Here, we performed a systematic review and meta-analysis to reveal the incidence of linezolid-induced thrombocytopenia and anemia, and impact of the administration period of linezolid on myelosuppression based on individual data analysis of pediatric patients.

METHODS

We systematically searched the Scopus, EMBASE, Cochrane Central Register of Controlled Trials, PubMed, and CINAHL until April 2020. We investigated the incidence of linezolid-induced thrombocytopenia and anemia using pooled analysis, and evaluated the impact of linezolid administration period on myelosuppression using meta-analysis.

RESULTS

Thirteen studies with 969 pediatric patients were identified. The pooled incidences of thrombocytopenia and anemia were 9% (95% confidence interval (CI), 3-18%) and 4% (95% CI, 0-12%), respectively. Our meta-analysis showed the extension of linezolid administration period (more than 14 days) resulted in higher incidence of thrombocytopenia (OR 4.86, 95% CI 1.10-21.55) and anemia (OR 4.57, 95% CI 0.13-160.49).

CONCLUSIONS

The incidence of linezolid-induced myelosuppression in pediatric patients was less than 10%. However, our meta-analysis revealed linezolid administration period for more than 14 days was one of risk factors associated with linezolid-induced myelosuppression. Therefore, especially for pediatric patients treated with linezolid for more than 14 days, careful monitoring of myelosuppression is required.

Managing the oncologic patient with suspected pneumonia in the intensive care unit

INTRODUCTION

Solid cancer patients are frequently admitted in intensive care units for critical events. Improving survival rates in this setting is considered an achievable goal today. Respiratory failure is the main reason for admission, representing a primary target for research.

AREAS COVERED

This review presents a diagnostic and therapeutic algorithm for pneumonia and other severe respiratory events in the solid cancer population. It aims to increase awareness of the risk factors and the different etiologies in this changing scenario in which neutropenia no longer seems to be a decisive factor in poor outcome. Bacterial pneumonia is the leading cause, but opportunistic diseases and non-infectious etiologies, especially unexpected adverse effects of radiation, biological drugs and monoclonal antibodies, are becoming increasingly frequent. Options for respiratory support and diagnostics are discussed and indications for antibiotics in the management of pneumonia are detailed. Expert commentary: Prompt initiation of critical care to facilitate optimal decision-making in the management of respiratory failure, early etiological assessment and appropriate antibiotic therapy are cornerstones in management of severe pneumonia in oncologic patients.

The immune response and antibacterial therapy

The host's immune defence mechanisms are indispensable factors in surviving bacterial infections. However, in many circumstances, the immune system alone is inadequate. Since the 1940s, the use of antibacterial therapy has saved millions of lives, improving the span and quality of life of individuals. Unfortunately, we are now facing an era where antibacterial agents are threatened by resistance. In addition to targeting bacteria, some antibacterial agents affect various aspects of the immune response to infection. Since many antibacterial drugs are failing in efficacy due to resistance, it has been strongly suggested that any synergy between these drugs and the immune response be exploited in the treatment of bacterial infections. This review explores the influence of antibacterial therapy on the immune response and new approaches that could exploit this interaction for the treatment of bacterial infections.

Staphylococcus aureus - antimicrobial resistance and the immunocompromised child

Children with immunocompromising conditions represent a unique group for the acquisition of antimicrobial resistant infections due to their frequent encounters with the health care system, need for empiric antimicrobials, and immune dysfunction. These infections are further complicated in that there is a relative paucity of literature on the clinical features and management of Staphylococcus aureus infections in immunocompromised children. The available literature on the clinical features, antimicrobial susceptibility, and management of S. aureus infections in immunocompromised children is reviewed. S. aureus infections in children with human immunodeficiency virus (HIV) are associated with higher HIV viral loads and a greater degree of CD4 T-cell suppression. In addition, staphylococcal infections in children with HIV often exhibit a multidrug resistant phenotype. Children with cancer have a high rate of S. aureus bacteremia and associated complications. Increased tolerance to antiseptics among staphylococcal isolates from pediatric oncology patients is an emerging area of research. The incidence of S. aureus infections among pediatric solid organ transplant recipients varies considerably by the organ transplanted; in general however, staphylococci figure prominently among infections in the early posttransplant period. Staphylococcal infections are also prominent pathogens among children with a number of immunodeficiencies, notably chronic granulomatous disease. Significant gaps in knowledge exist regarding the epidemiology and management of S. aureus infection in these vulnerable children.

Successful port-a-cath salvage using linezolid in children with acute leukemia

Central venous catheter (CVC) removal is indicated when persistent catheter-related bloodstream infection (CRBSI) occurs. This is a retrospective study to analyze the use of linezolid as a salvage therapy for CRBSIs due to coagulase-negative Staphylococci in children diagnosed with acute leukemia. Seven treatment courses of linezolid were administrated to six patients with port-type-CRBSI after non-effective intravenous vancomycin or teicoplanin treatment. Simultaneous lock and systemic therapy with linezolid avoided the removal of port-type-CVC in all cases. Treatment with linezolid was an alternative to catheter removal in these patients. Prospective studies are needed to confirm linezolid effectiveness as a salvage treatment in CRBSI.

Characteristics and outcomes of methicillin-resistant staphylococcus aureus bloodstream infections in patients with cancer treated with vancomycin: 9-year experience at a comprehensive cancer center

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections (BSIs) can cause significant morbidity and mortality in patients with cancer. However, data on outcomes of patients treated with vancomycin are lacking.

METHODS

We identified 223 patients with cancer who developed MRSA BSIs between January 2001 and June 2009 and were treated with vancomycin. Treatment failure was defined as death within 60 days of infection, persistent bacteremia ≥5 days, fever ≥4 days, recurrence or relapse, and secondary MRSA infection.

RESULTS

The treatment failure rate was 52% (116 of 223 patients). These patients were more likely to have been hospitalized, been treated with steroids within the previous 3 months, developed acute respiratory distress syndrome, required mechanical ventilation, required intensive care unit care, and community-onset infections (all p < .05). Risk factors for MRSA-associated mortality (27 of 223 patients; 12%) included hematologic malignancy and hematopoietic stem cell transplantation, community-onset infection, secondary BSI, MRSA with minimum inhibitory concentration (MIC) ≥2.0 μg/mL, mechanical ventilation, and a late switch to an alternative therapy (≥4 days after treatment failure; all p < .05). On multivariate analysis, mechanical ventilation and recent hospitalization were identified as independent predictors of vancomycin failure, and community-onset infection, secondary BSIs, and MIC ≥2 μg/mL were identified as significant predictors of MRSA-associated mortality.

CONCLUSIONS

We found a high treatment failure rate for vancomycin in patients with cancer and MRSA BSIs, as well as a higher mortality. A vancomycin MIC ≥2 μg/mL was an independent predictor of MRSA-associated mortality. An early switch to an alternative therapy at the earliest sign of failure may improve outcome.

Scaling adult doses of antifungal and antibacterial agents to children

My general pharmacokinetic scaling theory is discussed for the important matter of determining pediatric dosing for existing and new therapeutic drugs when optimal, or near-optimal, dosing for adults is known. The basis for the scaling is the requirement of a time-scaled likeness of the free-drug concentration time histories of children and adults. Broad categories of single and periodic dosing are considered. The former involves the scaling of dosage, and the latter involves both the dosage and schedule. The validity of the scaling relations is demonstrated by using measurements from previously reported clinical trials with adults and children (with ages generally 1 year or older) for the relatively new antifungal agent caspofungin and for the relatively new antibacterial agent linezolid. Standard pharmacodynamic effectiveness criteria are shown to be satisfied for the scaled dosage and schedule for children to the same extent that they are for the referenced adult. Consideration of scaling from adults to children is discussed for the case of new agents where no pediatric data are available and needed parameters are determined from in vitro measurements and preclinical animal data. A connection is also made between the allometric representation of clearance data and the dosing formulas. Limitations of the scaling results for infants because of growth and maturational matters are discussed. The general conclusion from this work is that the scaling theory does indeed have application to pediatric dosing for children, for both confirmation and refinement of present practice and guidance in pediatric treatment with new therapeutic agents.

Clinical experience with linezolid in infants and children

The worldwide spread of multidrug-resistant organisms has required the development of new antimicrobials. Linezolid, the first oxazolidinone, has a broad spectrum of activity against Gram-positive bacteria, including resistant strains. Although approved by the Food and Drug Administration in 2002, the clinical experience with linezolid in the paediatric population is still limited, also given the fact that in most European countries the paediatric use of linezolid is off-label. In this paper we summarize the actual evidence on both licensed and off-label clinical uses of linezolid in children, including efficacy, safety and tolerability issues. Taking into account the potential bias in comparing heterogeneous clinical trials and reports, the available literature data suggest that linezolid is a safe and effective agent for the treatment of serious Gram-positive bacterial infections in neonates and children. At present, linezolid is reserved for those children who are intolerant to or fail conventional agents. A linezolid-containing regimen can be a valuable option for treating multidrug-resistant and extensively drug-resistant tuberculosis in children as well as disseminated non-tuberculous mycobacterial infections. Given the rare occurrence of serious side effects, careful monitoring of haematological parameters, possible drug interactions and neurological manifestations is recommended in linezolid-treated children, especially in case of prolonged treatments. Appropriate linezolid dosage and hospital infection control measures are essential to avoid the spread of linezolid resistance. Further studies are needed to establish novel paediatric indications for linezolid use and to assess the tolerability of long-term treatments.