Cost-Effectiveness of Reclassifying Triptans in Australia: Application of an Economic Evaluation Approach to Regulatory Decisions

BACKGROUND

Migraine is a common, chronic, disabling headache disorder. Triptans, used as an acute treatment for migraine, are available via prescription in Australia. An Australian Therapeutic Goods Administration (TGA) committee rejected reclassifying sumatriptan and zolmitriptan from prescription medicine to pharmacist-only between 2005 and 2009, largely on the basis of concerns about patient risk. Nevertheless, pharmacist-only triptans may reduce migraine duration and free up healthcare resources.

OBJECTIVES

To estimate the cost-effectiveness of reclassifying triptans from prescription-only to pharmacist-only in Australia.

METHODS

The study design included decision-analytic modeling combining data from various sources. Behavior before and after reclassification was estimated using medical practitioner and patient surveys and also administrative data. Health outcomes included migraine frequency and duration as well as adverse events (AEs) discussed by the TGA committee. Efficacy and AEs were estimated using randomized controlled trials and observational studies.

RESULTS

Reclassifying triptans will reduce migraine duration but increase AEs. This will result in 337 quality-adjusted life-years gained at an increased cost of A$5.9 million over 10 years for all Australian adults older than 15 years (19.6 million). The incremental cost-effectiveness ratio was estimated to be A$17 412/quality-adjusted life-year gained.

CONCLUSIONS

The incremental cost-effectiveness ratio is likely to be considered cost-effective by Australian decision makers. Serotonin syndrome, a key concern of the TGA committee, had little impact on the results. Further research is needed regarding pharmacist-only triptan use by migraineurs currently using over-the-counter medicines and by nonmigraineurs, the efficacy of triptans, and the risk of cardiovascular and cerebrovascular AEs and chronic headaches with triptans.

LInezolid for the Treatment of Nocardia spp. Infections

Objective:

To review the available evidence regarding the use of linezolid for the treatment of Nocardia spp. infections.

Data Sources:

Data were identified through a search of MEDLINE (1966-May 2007), American Search Premier (1975-May 2007), International Pharmaceutical Abstracts (1960-2007), Science Citation Index Expanded (1996-2007), and Cochrane Databases (publications archived until May 2007) using the terms linezolid and Nocardia.

Study Selection and Data Extraction:

Prospective and retrospective studies, case reports, case series, and in vitro studies were eligible for inclusion if they used linezolid for nocardiosis regardless of site of infection and outcome.

Data Synthesis:

We identified 11 published cases of linezolid use for Nocardia spp. infections. The predominant species isolated were N. asteroides (n=4; 36%) and N. farcinica (n= 3; 27%). Nocardiosis with central nervous system involvement (n= 7; 64%) or disseminated disease (n= 4; 36%) were most common. The main reason for discontinuation of previous antimicrobials was most often related to adverse effects (n= 5; 45%), followed by clinical failure (n = 3; 27%). Linezolid was associated with cure or improvement in all cases (n =11; 100%). However, the majority of patients developed serious complications that may have led to premature discontinuation of therapy with linezolid, including myelosuppression (n = 5; 45%) or possible/confirmed peripheral neuropathy (n = 2; 18%).

Conclusions:

The limited published data suggest that linezolid appears to be an effective alternative to trimethoprim/sulfamethoxazole for the treatment of nocardiosis. Unfortunately, the high cost and potentially serious long-term toxicities of linezolid appear to limit its use and relegate it to salvage therapy alone or in combination with other antimicrobials.

Modeling economic implications of alternative treatment strategies for acute bacterial skin and skin structure infections

OBJECTIVE

The economic implications from the US Medicare perspective of adopting alternative treatment strategies for acute bacterial skin and skin structure infections (ABSSSIs) are substantial. The objective of this study is to describe a modeling framework that explores the impact of decisions related to both the location of care and switching to different antibiotics at discharge.

METHODS

A discrete event simulation (DES) was developed to model the treatment pathway of each patient through various locations (emergency department [ED], inpatient, and outpatient) and the treatments prescribed (empiric antibiotic, switching to a different antibiotic at discharge, or a second antibiotic). Costs are reported in 2012 USD.

RESULTS

The mean number of days on antibiotic in a cohort assigned to a full course of vancomycin was 11.2 days, with 64% of the treatment course being administered in the outpatient setting. Mean total costs per patient were $8671, with inpatient care accounting for 58% of the costs accrued. The majority of outpatient costs were associated with parenteral administration rather than drug acquisition or monitoring. Scenarios modifying the treatment pathway to increase the proportion of patients receiving the first dose in the ED, and then managing them in the outpatient setting or prescribing an oral antibiotic at discharge to avoid the cost associated with administering parenteral therapy, therefore have a major impact and lower the typical cost per patient by 11-20%. Since vancomycin is commonly used as empiric therapy in clinical practice, based on these analyses, a shift in treatment practice could result in substantial savings from the Medicare perspective.

CONCLUSIONS

The choice of antibiotic and location of care influence the costs and resource use associated with the management of ABSSSIs. The DES framework presented here can provide insight into the potential economic implications of decisions that modify the treatment pathway.

Zolmitriptan (Zomig®)

New triptans are being released in rapid succession with each addition demonstrating some specific pharmacokinetic properties, which may be translated into clinical advantages. Zolmitriptan (Zomig) offers a range of alternatives to migraine sufferers. The conventional tablet is consistently effective across a wide range of migraine subtypes. The orally disintegrating tablet offers an effective option for those migraineurs who are nauseated or need to take their medication earlier in the course of their migraine. Since it can be taken without fluid, the orally disintegrating tablet may be consistently used early in the migraine attack when the pain is still mild. The nasal spray aggregates all the benefits of the oral formulations and has a faster onset of action. The 5-mg dose of all three forms of zolmitriptan offers additional benefits over the 2.5-mg dose at early time points. The physician can now choose the optimum route of delivery of zolmitriptan to stop the headache, increase the likelihood of reducing disability and restore the patient to complete functionality.

Role of linezolid in the treatment of complicated skin and soft tissue infections

Staphylococcus aureus is the most common cause of complicated skin and soft tissue infections (cSSTIs). Antibiotic choices for these infections continue to evolve. History has seen penicillin progress to antistaphylococcal penicillins and cephalosporins, but these drugs are now giving way to drugs that are effective against methicillin-resistant S. aureus (MRSA). While vancomycin has been the gold standard to treat MRSA infections, newer therapeutic options have been developed over the last 5 years. These include quinupristin-dalfopristin, daptomycin, tigecycline and linezolid, which is the focus for this review. Linezolid is efficacious in the treatment of cSSTIs (including diabetic foot infections) caused by Gram-positive organisms (including MRSA), with a well-defined safety profile and straightforward dosing. It is also approved for nosocomial pneumonia, community-acquired pneumonia and uncomplicated skin and skin structure infections. Linezolid has an oral and parenteral formulation, which are equivalent. The oral formulation has the potential to offer economic benefits as compared with other therapies. Currently, there are only a few new antibiotics in development with MRSA activity. The proper use of all antibiotics, including these newer agents, is increasingly important if we are to slow the evolution of microbial resistance.

A practical guide to community-acquired MRSA

As the number of CA-MRSA skin and soft tissue infections continues to grow, it's important to know which patients are at greatest risk and which evidence-based treatment protocols to turn to when needed.

Out-of-pocket costs and prescription reversals with oral linezolid

OBJECTIVE

To determine the relationship between benefit design, out-of-pocket costs, and prescription reversals, and the impact of reversals on rehospitalizations and total healthcare costs among Medicare members prescribed oral linezolid.

STUDY DESIGN

Medicare members from a national health plan prescribed oral linezolid posthospitalization for skin and soft tissue infection (SSTI) or pneumonia were followed retrospectively.

METHODS

Members were identified by an oral linezolid prescription between June 1, 2007, and April 30, 2011, where the index event was a prescription fill or reversal less than 2 days before or 10 days after discharge. Associations between out-of-pocket costs and reversal, and between reversal and rehospitalization 30 days postindex, were compared for prescription fills versus reversals. A generalized linear model calculated adjusted total healthcare costs per member controlling for age, sex, geographic region, and clinical characteristics.

RESULTS

Reversal rates rose progressively from 2% for members with out-of-pocket costs of $0 to 27% for members with out-of-pocket costs higher than $100 (P < .0001). Infection-related rehospitalizations were 23% versus 9% for members with a prescription reversal versus a fill (P < .0001). While postdischarge prescription drug costs were $1228.78 lower (P <.0001), adjusted mean medical costs were $2061.69 higher (P = .0033) and total healthcare costs were $1280.93 higher (P = .0349) for reversal versus fill members.

CONCLUSIONS

Higher out-of-pocket costs were associated with higher rates of reversal, and reversals were associated with higher rates of rehospitalization and adjusted total healthcare costs among Medicare members prescribed oral linezolid posthospitalization for SSTI or pneumonia.

Cost-Effectiveness Analysis of the Treatment of Ventilator-Associated Pneumonia with Linezolid or Vancomycin in Spain

The aim of this study was to assess the cost-effectiveness of linezolid (LIN) versus vancomycin (VAN) for the treatment of ventilator-associated pneumonia (VAP) using a decision model analysis from the National Health System perspective. Patients and participants comprising four subgroups were analyzed: all, Gram-positive (GP), Staphylococcus aureus (SA), methicillin-resistant SA (MRSA). The treatments were LIN 600 mg i.v., every 12 hours, 10 days and VAN 1,000 mg i.v., every 12 hours 10 days. The primary outcome was the incremental cost-effectiveness of LIN in terms of cost per added quality-adjusted life year (QALY) gained. The secondary outcome was the marginal cost per year of life saved (LYS) generated by using LIN. Clinical cure and survival rates estimates were derived from a retrospective analysis of two trials comparing LIN with VAN. QALY was based on time-trade off study. Resource use and unit costs (Euros 2003) were obtained from Spanish VAP treatment and health cost databases. The additional QALY and LYS per LIN patients were 0.392; 0.688; 0.606; 1.805 and 0.471; 0.829; 0.729; 2.175 respectively, compared with those of VAN in the patients with VAP (all, GP, SA, and MRSA, respectively). The additional costs for LYS with LIN, as compared to VAN were 1,501.31; 827.63; 955.13 and 289.51 Euros, respectively. The additional cost per QALY with LIN was 1,803.87; 997.25; 1,149.00 and 348.85 Euros, respectively.

CONCLUSIONS

LIN was more cost-effective than VAN in the treatment of VAP in Spain, with an additional cost per QALY/LYS gained below the acceptable threshold in Spain of Euros 30,000 for new therapies.

[Pharmacoeconomic assessment of daptomycin as first-line therapy for bacteraemia and complicated skin and skin structure infections caused by gram-positive pathogens in Spain]

OBJECTIVE

To assess the efficiency of daptomycin as firstline therapy (D) versus daptomycin as salvage therapy after vancomycin (V→D ) or linezolid (L→D) failure in gram-positive bacteraemia and complicated skin and skin-structure infections (cSSTIs).

METHODS

Cost-effectiveness analysis of 161 bacteraemia and 84 cSSTIs patients comparing the above mentioned therapeutic alternatives was performed using the data from 27 Spanish hospitals involved in the EUCORE study. Direct medical costs were considered. Patients were observed from the first antibiotic dose for infection until either the end of daptomycin therapy or exitus. A multivariate Monte Carlo probabilistic sensitivity analysis was applied for costs (lognormal distribution) and effectiveness (normal distribution).

RESULTS

In terms of effectiveness there were no statistical differences between groups but referring total costs per patient, there were significant differences. Sensitivity analysis confirmed that D dominates over L→D between 44.2%-62.1% of simulations in bacteraemia and between 48.2%-67.5% in cSSTIs. In comparison to V→D, D dominance was detected in 29.2%-33.2% of simulations in bacteraemia and between 48.2%-59.3% in cSSTIs.

CONCLUSIONS

Daptomycin as first-line therapy dominates over daptomycin as salvage therapy after linezolid failure both in bacteraemia and cSSTIs. Comparing daptomycin as first-line therapy with its use after vancomycin failure, in cSSTIs the former is dominant. In bacteremia daptomycin as first line therapy is as effective as daptomycin as salvage therapy after vancomycin failure and implies lower costs.

Cost-effectiveness analysis of linezolid, daptomycin, and vancomycin in methicillin-resistant Staphylococcus aureus: complicated skin and skin structure infection using Bayesian methods for evidence synthesis

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) complicated skin and skin structure infection (cSSSI) is a prominent infection encountered in hospital and outpatient settings that is associated with high resource use for the health-care system.

OBJECTIVE

A decision analytic (DA) model was developed to evaluate the cost-effectiveness analysis (CEA) of linezolid, daptomycin, and vancomycin in MRSA cSSSI.

METHODS

Bayesian methods for evidence synthesis were used to generate efficacy and safety parameters for a DA model using published clinical trials. CEA was done from the US health-care perspective. Efficacy was defined as a successfully treated patient at the test of cure without any adverse reaction. Primary outcome was the incremental cost-effectiveness ratio between linezolid and vancomycin, daptomycin and vancomycin, and linezolid and daptomycin in MRSA cSSSI. Univariate and probabilistic sensitivity analyses were performed to test the robustness of the model.

RESULTS

The total direct costs of linezolid, daptomycin, and vancomycin were $18,057, $20,698, and $23,671, respectively. The cost-effectiveness ratios for linezolid, daptomycin, and vancomycin were $37,604, $44,086, and $52,663 per successfully treated patient, respectively. Linezolid and daptomycin were dominant strategies compared to vancomycin. However, linezolid was dominant when compared to daptomycin. The model was sensitive to the duration of daptomycin and linezolid treatment.

CONCLUSION

Linezolid and daptomycin are potentially cost-effective based on the assumptions of the DA model; however, linezolid appears to be more cost-effective compared to daptomycin and vancomycin for MRSA cSSSIs.

Cost-effectiveness analysis of linezolid vs. vancomycin in treating methicillin-resistant Staphylococcus aureus complicated skin and soft tissue infections using a decision analytic model

PURPOSE

To evaluate the cost-effectiveness of vancomycin vs. linezolid in complicated skin and soft tissue infections (cSSTIs) with methicillin-resistant Staphylococcus aureus (MRSA) using a decision analytic (DA) model.

METHODS

A DA model was created to evaluate the cost-effectiveness of four treatment strategies in the treatment of MRSA cSSTIs: linezolid intravenous (i.v.) to oral (LIN), vancomycin i.v. inpatient treatment (VAN-1), vancomycin i.v. switch to oral linezolid (VAN-2) and vancomycin i.v. switch to outpatient vancomycin i.v. (VAN-3). Probabilities were determined from published clinical trials. Incremental cost-effectiveness ratios for the various strategies were the primary outcome. Univariate (one-way) sensitivity analysis and second-order Monte Carlo simulation (using 10,000 trials) were conducted for all parameters used in the model.

RESULTS

The DA model predicted that VAN-3 was the most cost-effective strategy from the base-case analysis. Average cost-effectiveness ratio for this strategy was $26,831.42/cure. Univariate sensitivity analysis revealed that the model was sensitive to linezolid duration of inpatient stay and duration of i.v. vancomycin before switching to an oral agent or discharged with outpatient i.v. administration with vancomycin. Probabilistic sensitivity analysis showed that VAN-1 was dominated by LIN, but LIN was only 30% cost-effective compared with VAN-3. Acceptability curve showed that the probability of choosing LIN as a cost-effective strategy compared with VAN-1, VAN-2 and VAN-3 increased as the willingness-to-pay (WTP) increased.

CONCLUSION

Alternative vancomycin strategies (VAN-2 and VAN-3) that take advantage of early discharge opportunities were cost-effective compared with LIN. However, LIN's higher efficacy would make it cost-effective for payers with a high WTP threshold.

Cost-effectiveness of linezolid versus vancomycin for hospitalised patients with complicated skin and soft-tissue infections in Germany

This study used a decision analytic model approach to evaluate the cost-effectiveness of linezolid versus vancomycin in the empirical treatment of complicated skin and soft-tissue infection (cSSTI) due to suspected methicillin-resistant Staphylococcus aureus (MRSA) from the German hospital and health care system perspective. Clinical probabilities were obtained from trial data, resource utilisation and MRSA prevalence rates were obtained through German physician interviews, and costs from published sources were applied to resource units. Outcomes included total cost/patient and cure. The estimated first-line cure rate for linezolid-treated patients was 90.1% versus 85.5% for vancomycin; total cure rates after two lines of treatment were 98.4% and 98.1%, respectively. Average total cost/episode was 8,232 euro for linezolid versus 9,206 euro for vancomycin. The model outcomes were sensitive to changes in length of stay (LOS), isolation days, rate of confirmed MRSA and price of linezolid. Linezolid was expected to result in a shorter intravenous treatment duration and shorter LOS that offset its higher acquisition cost versus vancomycin in cSSTI in Germany.

Economic evaluation of linezolid versus teicoplanin for the treatment of infections caused by gram-positive microorganisms in Spain

The aim of this study was to perform a comparative cost-effectiveness analysis of linezolid vs teicoplanin (i.v., switching to oral/i.m. respectively) in Spain. A decision tree model was used with the results of a randomized, comparative, controlled clinical trial with linezolid vs teicoplanin in the treatment of infections caused by Gram-positive microorganisms, with a timeline of 31 days. The efficacy endpoint was the percentage of patients with clinical healing or improvement in their infection. Direct medical costs were included using Spanish 2005 prices. Average cost per patient, average cost-effectiveness ratio and several sensitivity analyses were carried out. In the intent-to-treat (ITT) analysis linezolid obtained a higher percentage of therapeutic success than teicoplanin (95.5% vs 87.6% respectively, p = 0.005), both with similar tolerability. The average cost per treated patient was euro 8,064.76 for linezolid vs euro 8,727.36 for teicoplanin, with an incremental cost of euro 622.59 (-7,6%). Linezolid yielded a lower average cost-effectiveness ratio, euro 8,444.78 (8,195.90 - 8,709.25) than teicoplanin, euro 9,962.74 (9,465.68 - 10,502.23), with a slight reduction in average cost per successfully treated patient of 15.2% ( euro 1,517.96). The results were robust to the sensitivity analysis. In conclusion, linezolid is a more cost-effective option than teicoplanin in the treatment of infections caused by Gram-positive microorganisms, since it offers superior clinical benefits with a lower use of associated resources.

A comparison of costs and hospital length of stay associated with intravenous/oral linezolid or intravenous vancomycin treatment of complicated skin and soft-tissue infections caused by suspected or confirmed methicillin-resistant Staphylococcus aureus in elderly US patients

OBJECTIVES

This study compared the costs and hospital length of stay (LOS) and duration of intravenous therapy associated with intravenous/oral linezolid or intravenous vancomycin treatment of complicated skin and soft-tissue infections (cSSTIs) caused by suspected or confirmed methicillin-resistant Staphylococcus aureus (MRSA) in elderly US patients.

METHODS

Data were obtained from elderly (>or=65 years) US patients participating in a multinational randomized trial of hospitalized cSSTI patients treated with linezolid or vancomycin. Costs (hospital and total) from the provider perspective were estimated for intent-to-treat (ITT) patients (ie, all those receiving >or=1 dose) using national 2003 costs (ward, medication, intravenous administration). LOS for inpatient care, duration of intravenous linezolid and vancomycin therapy (ITT and MRSA groups), and cure rates were evaluated.

RESULTS

Of 717 enrolled subjects, 163 (23%) were elderly (87 linezolid, 76 vancomycin), with no significant differences in demographic characteristics between the linezolid and vancomycin groups. Mean hospitalization and total costs were lower with linezolid compared with vancomycin (hospitalization: US $4510 vs US $6478, P<0.001; total: US $6009 vs US $7329, P=0.03). Linezolid was associated with a 3.5-day reduction in LOS and a 9.5-day reduction in the duration of intravenous therapy compared with vancomycin in the ITT group (both, P<0.001). Cure rates were comparable between linezolid and vancomycin in both the ITT group (88.7% vs 81.4%, respectively) and the MRSA group (80.0% vs 71.4%). In multivariate analyses of the ITT group, linezolid patients were 57% less likely than vancomycin patients to have a LOS >7 days (odds ratio = 0.43; 95% CI, 0.21-0.87). Chronic renal failure, malnutrition, and a diagnosis of infected ulcer predicted an LOS >7 days.

CONCLUSIONS

In this analysis of data from elderly patients with cSSTI caused by suspected or confirmed MRSA, linezolid treatment was associated with reductions in the costs of care, LOS, and duration of intravenous treatment without affecting the clinical outcomes. Although the use of a subset of patients from a larger trial that did not focus on the elderly can be seen as a study limitation, the elderly represent an important population when evaluating health care resource use and costs.

Linezolid versus Vancomycin for Prosthetic Joint Infections: a Cost Analysis

BACKGROUND

Prosthetic joint infections (PJIs) caused by methicillin-resistant gram-positive bacteria are primarily treated by intravenous vancomycin. Linezolid, active against methicillin-resistant strains and available in oral and intravenous dosage forms, is a potential alternative to vancomycin for the treatment of PJIs.

OBJECTIVE

To analyze the cost of linezolid therapy (outpatient setting) and vancomycin therapy (inpatient and outpatient settings) for PJIs caused by methicillin-resistant gram-positive bacteria.

METHODS

A decision tree was designed to simulate the clinical outcome and healthcare resource utilization of linezolid, vancomycin by outpatient and home parenteral antimicrobial therapies (OHPAT) and vancomycin administered in inpatient setting (rehabilitation facility) for patients with PJIs caused by methicillin-resistant strains. Clinical inputs were estimated from literature and the cost analysis was conducted from the perspective of the public healthcare provider in Hong Kong.

RESULTS

The base-case analysis showed that the vancomycin (OHPAT) group (USD14,470 per patient) was the least costly alternative, followed by the linezolid group (USD17,877 per patient) and the vancomycin (rehabilitation) group (USD19,980 per patient) (1USD = 7.8HKD). The clinical treatment success rates of vancomycin and linezolid were influential factors. Monte Carlo 10,000 simulations showed that the vancomycin (OHPAT) group was less costly than the arms of linezolid and vancomycin (rehabilitation) 64% and 100% of the time, respectively. The linezolid group was less costly than the vancomycin (rehabilitation) group in 65%of the times.

CONCLUSION

Home-infusion of vancomycin therapy appears to be the least costly treatment approach for PJIs caused by methicillin-resistant gram-positive bacteria from the perspective of a Hong Kong public health organization.

Role of linezolid in the treatment of orthopedic infections

Gram-positive organisms, particularly staphylococci and streptococci, are responsible for the majority of bone and joint infections. The rising incidence of antimicrobial resistance among Staphylococcus aureus, coagulase-negative staphylococci and enterococci means that novel antibiotics with unique mechanisms of antimicrobial activity are needed, especially in orthopedic infections. Linezolid is the first of the oxazolidinones, a new class of antibacterial agents particularly effective against Gram-positive infections including methicillin- and vancomycin-resistant strains. With an excellent oral bioavailability and acceptable safety profile, linezolid offers a valuable alternative to more traditional therapies, such as glycopeptides. No large randomized trials have been published on its use in patients with orthopedic infections, but early results are encouraging. Reported adverse events, especially bone marrow suppression and optic neuropathy seen with prolonged administration, mean that treatment of such patients must be undertaken with careful follow-up of laboratory tests. Until now, little resistance has been reported.