Cost analysis of switching from IV vancomycin to PO linezolid for the management of methicillin-resistant Staphylococcus species

Core Elements for Implementing Antimicrobial Stewardship Programs in Korean General Hospitals

Currently, antimicrobial resistance (AMR) is a major threat to global public health. The antimicrobial stewardship program (ASP) has been proposed as an important approach to overcome this crisis. ASP supports the optimal use of antimicrobials, including appropriate dosing decisions, administration duration, and administration routes. In Korea, efforts are being made to overcome AMR using ASPs as a national policy. The current study aimed to develop core elements of ASP that could be introduced in domestic medical facilities. A Delphi survey was conducted twice to select the core elements through expert consensus. The core elements for implementing the ASP included (1) leadership commitment, (2) operating system, (3) action, (4) tracking, (5) reporting, and (6) education. To ensure these core elements are present at medical facilities, multiple departments must collaborate as teams for ASP operations. Establishing a reimbursement system and a workforce for ASPs are prerequisites for implementing ASPs. To ensure that ASP core elements are actively implemented in medical facilities, it is necessary to provide financial support for ASPs in medical facilities, nurture the healthcare workforce in performing ASPs, apply the core elements to healthcare accreditation, and provide incentives to medical facilities by quality evaluation criteria.

When to switch to an oral treatment and/or to discharge a patient with skin and soft tissue infections

PURPOSE OF REVIEW

Skin and soft tissue infections prevalence is increasing and represent a frequent cause of hospital admission. New guidelines have become available in order to better define these infections and their response to antimicrobial treatment. Gram-positive bacteria, in particular Staphylococcus aureus, remain the most frequently isolated pathogens in skin and soft tissue infections. To treat complicated forms and infections caused by drug-resistant bacteria, hospital admission and administration of intravenous antibiotics are often required, impacting on healthcare costs and patients' morbidity.

RECENT FINDINGS

New therapeutic options offer efficacy against drug-resistant Gram-positive bacteria as well as potential to favor early patients' discharge, including the possibility for intravenous to oral switch and infrequent drug administration because of prolonged drug half-life. Although data from real-world studies on new antimicrobials is awaited, clinicians need clear direction on how to optimize the treatment of skin and soft tissue infections in order to avoid prolonged hospitalizations and extra costs. Early assessment of patient's clinical conditions and response to treatment appear useful in order to facilitate patients' discharge.

SUMMARY

We have reported the evidence for early intravenous to oral switch and early hospital discharge for patients with skin and soft tissue infections. New therapeutic options that represent promising tools in promoting an optimized management of these infections have also been reviewed.

Effectiveness of sequential intravenous-to-oral antibiotic switch therapy in hospitalized patients with gram-positive infection: the SEQUENCE cohort study

Switching from intravenous to oral antibiotic therapy may improve inpatient management and reduce hospital stays and the complications of intravenous treatment. We aimed to assess the effectiveness of intravenous-to-oral antibiotic switch therapy and an early discharge algorithm in hospitalized patients with gram-positive infection. We performed a prospective cohort study with a retrospective comparison cohort, recruited from eight tertiary, acute-care Spanish referral hospitals. All patients included had culture-confirmed methicillin-resistant gram-positive infection, or methicillin-susceptible gram-positive infection and beta-lactam allergy and had received intravenous treatment with glycopeptides, lipopeptides, or linezolid. The study comprised two cohorts: the prospective cohort to assess the effectiveness of a sequential intravenous-to-oral antibiotic switch algorithm and early discharge, and a retrospective cohort in which the algorithm had not been applied, used as the comparator. A total of 247 evaluable patients were included; 115 in the prospective and 132 in the retrospective cohort. Forty-five retrospective patients (34 %) were not changed to oral antibiotics, and 87 (66 %) were changed to oral antibiotics without following the proposed algorithm. The duration of hospitalization was significantly shorter in the prospective cohort compared to the retrospective group that did not switch to oral drugs (16.7 ± 18.7 vs 23 ± 13.4 days, P  < 0.001). No differences were observed regarding the incidence of catheter-related bacteraemia (4.4 % vs 2.6 %, P = 0.621). Our results suggest that an intravenous-to-oral antibiotic switch strategy is effective for reducing the length of hospital stay in selected hospitalized patients with gram-positive infection.

Cost-Effectiveness of Linezolid versus Vancomycin among Patients with Methicillin-Resistant Staphylococcus aureus Confirmed Nosocomial Pneumonia in China

OBJECTIVE

To estimate the cost-effectiveness of intravenous linezolid as a first-line agent against intravenous vancomycin in treating methicillin-resistant Staphylococcus aureus-confirmed nosocomial pneumonia in four Chinese cities.

METHODS

A decision-analytic model of 4-week time horizon was used to conduct cost-effectiveness analyses from the payer's perspective. Clinical outcomes and resource use data were derived from a head-to-head trial, supplemented with local cost estimates based on hospital data via an expert panel. A series of scenario analyses were conducted to evaluate the impact of uncertainty around model inputs. All results were reported in 2012 Chinese Renminbi.

RESULTS

The predicted probability of overall treatment success was 0.629 and 0.602 for linezolid and vancomycin, respectively. Total inpatient costs varied across the four cities, ranging from ¥58,835 to ¥86,894 for linezolid and ¥58,390 to ¥87,033 for vancomycin, respectively. Linezolid was demonstrated to be a dominant treatment strategy in Guangzhou. In Beijing, Nanjing, and Xi'an, incremental cost-effectiveness ratios in terms of additional successfully treated patient were ¥1,861, ¥163, and ¥16,509, respectively. Dominance by linezolid was observed in some scenario analyses with parameters such as treatment duration, inclusion of cost of managing adverse events, and drug acquisition costs being the main drivers of cost-effectiveness results.

CONCLUSIONS

Despite linezolid's higher drug acquisition cost, its superior clinical efficacy renders it a likely cost-effective alternative for the treatment of methicillin-resistant Staphylococcus aureus-confirmed nosocomial pneumonia as compared with branded vancomycin from the payer perspectives of Beijing, Guangzhou, Nanjing, and Xi'an.

Treatment of infections due to resistant Staphylococcus aureus

This chapter reviews data on the treatment of infections caused by drug-resistant Staphylococcus aureus, particularly methicillin-resistant S. aureus (MRSA). This review covers findings reported in the English language medical literature up to January of 2013. Despite the emergence of resistant and multidrug-resistant S. aureus, we have seven effective drugs in clinical use for which little resistance has been observed: vancomycin, quinupristin-dalfopristin, linezolid, tigecycline, telavancin, ceftaroline, and daptomycin. However, vancomycin is less effective for infections with MRSA isolates that have a higher MIC within the susceptible range. Linezolid is probably the drug of choice for the treatment of complicated MRSA skin and soft tissue infections (SSTIs); whether it is drug of choice in pneumonia remains debatable. Daptomycin has shown to be non-inferior to either vancomycin or β-lactams in the treatment of staphylococcal SSTIs, bacteremia, and right-sided endocarditis. Tigecycline was also non-inferior to comparator drugs in the treatment of SSTIs, but there is controversy about whether it is less effective than other therapeutic options in the treatment of more serious infections. Telavancin has been shown to be non-inferior to vancomycin in the treatment of SSTIs and pneumonia, but has greater nephrotoxicity. Ceftaroline is a broad-spectrum cephalosporin with activity against MRSA; it is non-inferior to vancomycin in the treatment of SSTIs. Clindamycin, trimethoprim-sulfamethoxazole, doxycycline, rifampin, moxifloxacin, and minocycline are oral anti-staphylococcal agents that may have utility in the treatment of SSTIs and osteomyelitis, but the clinical data for their efficacy is limited. There are also several drugs with broad-spectrum activity against Gm-positive organisms that have reached the phase II and III stages of clinical testing that will hopefully be approved for clinical use in the upcoming years: oritavancin, dalbavancin, omadacycline, tedizolid, delafloxacin, and JNJ-Q2. Thus, there are currently many effective drugs to treat resistant S. aureus infections and many promising agents in the pipeline. Nevertheless, S. aureus remains a formidable adversary, and despite our deep bullpen of potential therapies, there are still frequent treatment failures and unfortunate clinical outcomes. The following discussion summarizes the clinical challenges presented by MRSA, the clinical experience with our current anti-MRSA antibiotics, and the gaps in our knowledge on how to use these agents to most effectively combat MRSA infections.

General principles of antimicrobial therapy

Antimicrobial agents are some of the most widely, and often injudiciously, used therapeutic drugs worldwide. Important considerations when prescribing antimicrobial therapy include obtaining an accurate diagnosis of infection; understanding the difference between empiric and definitive therapy; identifying opportunities to switch to narrow-spectrum, cost-effective oral agents for the shortest duration necessary; understanding drug characteristics that are peculiar to antimicrobial agents (such as pharmacodynamics and efficacy at the site of infection); accounting for host characteristics that influence antimicrobial activity; and in turn, recognizing the adverse effects of antimicrobial agents on the host. It is also important to understand the importance of antimicrobial stewardship, to know when to consult infectious disease specialists for guidance, and to be able to identify situations when antimicrobial therapy is not needed. By following these general principles, all practicing physicians should be able to use antimicrobial agents in a responsible manner that benefits both the individual patient and the community.

Multiresistant bacteria and current therapy - the economical side of the story

Severe infections with multiresistant bacteria (MRB) are a medical challenge and a financial burden for hospitals. The adequate antibiotic therapy is a key issue in multiresistant bacteria management. Several major cost drivers have been identified. Remarkably drug acquisition costs are not necessarily included. Most significant are the length of stay in hospital, the hours of mechanical ventilation and the time treated on an intensive care unit.

In a systematic review of the literature the following aspects were investigated:

- Do generic treatment strategies contribute in cost savings?

- Are there specific results for recent antibiotics?

Early adequate and effective antimicrobial treatment, switch from i.v. to oral therapy, adjusted duration of therapy and adherence to guidelines have been found to be successful strategies.

Looking at specific antibiotics, the best evidence for cost-effectiveness is found for Linezolid in treatment of cSSTI as well as in HAP. Daptomycin shows good economic results in bloodstream infections, so possibly being a cost-effective alternative to vancomycin. Looking at tigecycline the published data show neither higher costs nor savings compared to imipeneme. Doripenem as one of the newest therapy options has proven to be highly cost-saving in HAP when compared with imipenem. However, most analyses are based on pharmacoeconomic modelling rather than on directly analysing trial data or real life clinical populations.

Health economic issues in the treatment of drug-resistant serious Gram-positive infections

Escalating health care costs have stimulated a paradigm change in the way health care is delivered, reimbursed, and evaluated. Reducing the length of hospital stay and controlling the cost of new technologies and therapies are major factors driving health care decisions. Economic evaluations have had variable success in the decision-making process, partly due to the overall quality, interpretation, and reporting of published analyses. Compared with other Gram-positive pathogens, the economic impact of methicillin-resistant Staphylococcus aureus (MRSA) infections remains the most studied. MRSA infections clearly represent a significant clinical and fiscal burden and future studies analyzing cost-effective strategies that encompass their prevention and optimal management would be beneficial. These studies would need to be carefully designed with clear objectives and explicit perspectives at the onset. Use of an appropriate reference group is key in the design process to measure the true impact of MRSA infections. Health-economic outcome data of the impact of linezolid compared with glycopeptides remain the most robust data available in this therapeutic area.

Linezolid for the treatment of drug-resistant infections

Multidrug-resistant pathogens have become increasingly common in contemporary healthcare. Specific to Gram-positive pathogens, methicillin-resistant Staphylococcus aureus (MRSA) is of particular concern, as it has been associated with increased hospital length of stay, higher healthcare expenditures and poorer outcomes. To date, linezolid is the first and only oxazolidinone approved by the US FDA for the treatment of infections caused by Gram-positive pathogens, including MRSA. This article will serve as a comprehensive review of linezolid, including an overview of the current market and its in vitro activity, with an in-depth review of its pharmacokinetic and pharmacodynamic profile. Emphasis will be placed on clinical data for the drug, both on- and off-label. The article will conclude with a brief overview of linezolid's pharmacoeconomic implications and safety profile, followed by a commentary and 5-year prospective analysis remarking on the future of the antimicrobial field as it relates to MRSA.

Pharmacoeconomics of linezolid

BACKGROUND

New antibiotics efficacious in infections caused by resistant Gram-positive microorganisms and with acceptable costs for national health systems per unit of effectiveness are needed.

OBJECTIVE

This paper aimed to summarize all available evidence regarding the pharmacoeconomics of linezolid.

METHODS

A systematic review of pharmacoeconomic analyses through a non-restricted literature search was conducted.

RESULTS/CONCLUSIONS

Linezolid, as compared to vancomycin and teicoplanin, results in a reduction of the necessary resources for the treatment of infections caused by Gram-positive microorganisms. These benefits are attributable to clinical outcomes and to savings associated with the ease of switching from intravenous to oral administration, the shorter duration of intravenous therapy and earlier hospital discharge. Likewise, linezolid, compared to vancomycin and teicoplanin, is a cost-effective treatment.

Treatment of infections caused by resistant Staphylococcus aureus

We review data on the treatment of infections caused by drug-resistant Staphylococcus aureus, particularly methicillin-resistant S. aureus (MRSA). In this review, we cover findings reported in the English language medical literature up to February 2006. Despite the emergence of resistant and multidrug resistant S. aureus, five effective drugs for which little resistance has been observed are in clinical use: vancomycin, quinupristin-dalfopristin, linezolid, tigecycline, and daptomycin. However, vancomycin is less effective for infections with MRSA isolates that have a high minimum inhibitory concentration in the susceptible range. Linezolid looks promising in the treatment of MRSA pneumonia and skin and soft-tissue infections (SSTIs). Daptomycin displays rapid bactericidal activity in vitro, and it has been shown to be noninferior to comparator agents in the treatment of SSTIs and bacteremia. Tigecycline was also noninferior to comparator drugs in the treatment of SSTIs. Clindamycin, trimethoprim-sulfamethoxazole, doxycycline, and minocycline are oral antistaphylococcal agents that may have utility in the treatment of SSTIs and osteomyelitis, but the clinical data for their efficacy is limited. There are four drugs with broad-spectrum activity against Gram-positive organisms at an advanced stage of clinical testing: ceptobiprole and three new glycopeptides with potent bactericidal activity, oritavancin, dalbavancin, and telavancin. Thus, there are currently many effective drugs to treat resistant S. aureus infections and many promising agents in the pipeline. Nevertheless, S. aureus remains a formidable adversary against which there are frequent treatment failures. The next goals are to determine the most appropriate indications and cost-effectiveness of each of these drugs in the treatment strategy against S. aureus.

Impact of linezolid on economic outcomes and determinants of cost in a clinical trial evaluating patients with MRSA complicated skin and soft-tissue infections

BACKGROUND

In clinical trials, linezolid has demonstrated higher clinical cure rates and shorter hospital duration for patients than has vancomycin for the treatment of complicated skin and soft-tissue infections (cSSTIs).

OBJECTIVE

To assess economic outcomes of linezolid versus vancomycin and evaluate determinants of treatment costs for cSSTIs.

METHODS

Economic data were obtained from US subjects enrolled in a multinational, open-label, clinical trial of cSSTIs caused by suspected or proven methicillin-resistant Staphylococcus aureus (MRSA). Subjects were randomized to receive intravenous or oral linezolid or intravenous vancomycin for 7-21 days. Costs for each patient were evaluated by applying nationally representative per diem hospital costs by hospital ward. Intravenous administration costs were applied to the duration of intravenous treatment. Factors contributing to the cost of therapy were evaluated using multivariate regression analysis.

RESULTS

Seven hundred seventeen US patients were included in the study. Demographics were similar between treatment groups. Length of stay and duration of intravenous therapy were shorter for linezolid-treated patients. Mean +/- SD cost for intent-to-treat population patients treated with linezolid versus vancomycin was 4865 US dollars +/- 4367 versus 5738 US dollars +/- 5190, respectively (p = 0.017), and in the MRSA population was 4881 US dollars +/- 3987 versus 6006 US dollars +/- 5039, respectively (p = 0.041). Factors significantly associated with increased cost included vancomycin therapy, age, and comorbidities, including diabetes. After adjusting for all other factors, treatment with linezolid was associated with significantly lower treatment costs compared with vancomycin.

CONCLUSIONS

Linezolid therapy was associated with improved clinical outcomes and significantly lower treatment costs than was vancomycin. The largest cost advantage was demonstrated in patients with documented MRSA cSSTIs.

Pharmacoeconomics of treatment with the newer anti-Gram-positive agents

The unmet medical need of emerging resistance among Gram-positive pathogens, such as methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci and penicillin-resistant Streptococcus pneumoniae, has driven industry towards the identification and development of novel anti-Gram-positive agents. Among the newer agents are improved quinolones, a lipopeptide, an oxazolidinone and novel glycopeptides. Scientific distinctions between these drugs, which impact on the placement, usage and, ultimately, the pharmacoeconomics of several of these new agents, may lead to further consideration despite poor initial observations of minimal improvement. Key differences in the characteristics of these drugs (i.e., spectrum, activity, resistance emergence, efficacy, target, safety) provide a basis for an emerging pharmacoeconomic-based distinction between these newer anti-Gram-positive agents.

Linezolid reduces length of stay and duration of intravenous treatment compared with vancomycin for complicated skin and soft tissue infections due to suspected or proven methicillin-resistant Staphylococcus aureus (MRSA)

We compared the health outcomes in patients treated with linezolid or vancomycin for complicated skin and soft tissue infections (cSSTIs). This analysis is part of a randomised, open-label, multinational trial involving 1200 adult patients hospitalised with cSSTIs due to suspected or proven methicillin-resistant Staphylococcus aureus (MRSA). Subjects received linezolid 600 mg intravenous (i.v.) or oral, or vancomycin 1g i.v. every 12 h. A test-of-cure was assessed at 7 days post therapy. Compared with vancomycin, linezolid treatment was associated with significantly shorter length of stay (all P < 0.01), decreased i.v. antibiotic treatment duration (all P < 0.0001) and higher discharge rates (all P < 0.05). Thus, linezolid has the potential to reduce medical resource use for the treatment of cSSTIs.