Caspofungin versus liposomal amphotericin B for empirical antifungal therapy in patients with persistent fever and neutropenia

The effects of caspofungin and voriconazole in an experimental fungal infection of the ear due to Aspergillus

The purpose of the study was to evaluate the effectiveness of caspofungin and voriconazole in the treatment of experimental Aspergillus otitis media in an experimental rabbit model. A total of 30 New Zealand white rabbits were divided into four treatment groups and one control group. The rabbits were immunosuppressed by cyclophosphamide and triamcinolone acetonide. The right ear of each rabbit was infected by an injection of the inoculum of 0.1 ml (8.6 x 103 CFU/0.1 ml) of Aspergillus fumigatus into the middle ear cavity. At 72 h after the inoculation, amphotericin B 1 mg/kg per day (n = 6), itraconazole 10 mg/kg per day (n = 6), voriconazole 10 mg/kg per day (n = 6) and caspofungin 5 mg/kg per day (n = 6) were injected to each treatment group. No antifungal drug was administered to the control group (n = 6). Clinical and histopathological examination scores and microbiological analysis of middle ear mucosa were compared.There was statistically significant difference in the clinical scores, histopathological scores, and mean CFU/g between the treatment and control groups (P < 0.05). There was no statistically significant difference among the treatment groups in the clinical and histopathological scores, whereas there was statistically significant difference in the mean CFU/g (P < 0.05). The mean CFU/g of amphotericin B and caspofungin groups were similar and both were lower than the itraconazole and voriconazole groups. Also, the mean CFU/g of voriconazole group was lower than the itraconazole group (P < 0.05). Caspofungin and voriconazole were demonstrated at least as effective as amphotericin B and itraconazole. We suggest that caspofungin and voriconazole may be considered for the treatment of fungal infection of the ear.

Detection of Aspergillus DNA by a nested PCR assay is able to improve the diagnosis of invasive aspergillosis in paediatric patients

Fungal infections are a leading cause of morbidity and mortality in severely immunocompromised patients and have been increasing in incidence in recent years. Invasive aspergillosis (IA) is the most common filamentous fungal infection and is, in adults as well as in children, difficult to diagnose. Several PCR assays to detect Aspergillus DNA have been established, but so far, studies on molecular tools for the diagnosis of IA in children are few. We evaluated the results of a nested PCR assay to detect Aspergillus DNA in clinical samples from paediatric and adolescent patients with suspected IA. Blood and non-blood samples from immunocompromised paediatric and adolescent patients with suspected invasive fungal infection were sent for processing Aspergillus PCR to our laboratory. PCR results from consecutive patients from three university children's hospitals investigated between November 2000 and January 2007 were evaluated. Fungal infections were classified according to the EORTC classification on the grounds of clinical findings, microbiology and radio-imaging results. Two hundred and ninety-one samples from 71 patients were investigated for the presence of Aspergillus DNA by our previously described nested PCR assay. Two, 3 and 34 patients had proven, probable and possible IA, respectively. Sensitivity (calculated from proven and probable patients, n=5) and specificity (calculated from patients without IA, n=32) rates of the PCR assay were 80 and 81 %, respectively. Our nested PCR assay was able to detect Aspergillus DNA in blood, cerebrospinal fluid and bronchoalveolar lavage samples from paediatric and adolescent patients with IA with high sensitivity and specificity rates.

Breakthrough rhinocerebral mucormycosis in a liver transplant patient receiving caspofungin

Zygomycetes are among the most frequent causes of non-Aspergillus mycelial fungal infections in transplant recipients. We have described a single case of breakthrough zygomycosis. A young Japanese woman presented because of idiopathic fulminant hepatitis and renal failure. On the third day of admission, she underwent orthotopic liver transplantation. A considerable amount of red blood cells and fresh frozen plasma were transfused during surgery. On posttransplant day 2, Candida albicans was isolated from respiratory secretions; prophylactic caspofungin was prescribed. During the next 6 days, C albicans was isolated from tracheal secretions, surgical wound, and exudates and stools. Ventilator-associated pneumonia was diagnosed day 4. Her renal function did not improve during the postoperative period; the patient continued on hemodialysis. On day 28, a dark blue eschar due to zygomycosis was detected on the skin of the nose. Tracheal and nasal exudates yielded Rhizopus sp. The patient died 12 hours later due to multiorgan failure with hypothermia. The fatal evolution in this case may be related to a presumed brain infarction after progressive vessel fungal invasion. The presented case had 2 risk factors related to zygomycosis. A high index of suspicion is required in transplant recipients with risk factors for zygomycosis. Early diagnosis and surgery with appropriate systemic fungal drugs (amphotericin B) are mandatory to improve the prognosis.

Invasive candidiasis and candidemia: from current opinions to future perspectives

Candida spp. are the fourth most common cause of nosocomial bloodstream infections in the United States, as well as the single most important cause of opportunistic fungal infections worldwide. A delayed diagnosis of invasive candidiasis and/or inadequate treatment choice is associated with high mortality rates and prolonged hospital stays. Even though the antifungal armamentarium has been broadened significantly over the last years, the best options for diagnosing and treating invasive candidiasis still remain a matter of discussion. In this article we present and analyze current evidence on the epidemiology, diagnostic methods and treatment options of invasive candidiasis, with a focus on results from randomized clinical trials. Finally, the reader is provided with a brief overview on promising clinical trial designs and antifungals that might shape the treatment of invasive candidiasis in the years to come.

Antifungal treatment strategies in high risk patients

We discuss different strategies for the treatment of invasive fungal infections (IFI) in high risk patients with a focus on patients experiencing profound and prolonged neutropenia, comprising those with acute myelogenous leukaemia (AML) or myelodysplastic syndrome (MDS) during remission induction chemotherapy and on patients undergoing allogeneic haematopoietic stem cell transplantation (SCT). Among these patients, invasive aspergillosis (IA) is the most frequently observed form of IFI, as opposed to high risk intensive care unit (ICU) patients in whom an increased incidence of invasive candidiasis (IC) can be observed. In both groups, initiation of early treatment has a profound impact on mortality rates, but adequate diagnostic tools are lacking. These circumstances have led to the parallel use of different treatment strategies, e.g. prophylaxis, empiric, pre-emptive and targeted treatment of IFI. The optimum treatment strategies for these severe infections are a matter of extensive research and discussion. A review of major clinical trials on the issue reveals that comparisons between different treatment strategies cannot be made. Considering the complexity of the issue, we advocate an eclectic treatment approach that reduces morbidity and mortality from IFI without compromising tolerability. In allogeneic HSCT recipients, patients receiving induction chemotherapy for AML or MDS and those under immunosuppressive medication for graft vs. host disease after allogeneic HSCT, we recommend prophylaxis with posaconazole. For empiric treatment of persistently febrile neutropenic patients, we opt for caspofungin as first and liposomal amphotericin B deoxycholate (L-AmB) as second line choice. If the diagnosis of IA can be established, voriconazole should be favoured over the alternative, liposomal amphotericin B (L-AmB). While high risk ICU patients benefit from fluconazole prophylaxis for IC, the choice of an optimal agent for targeted therapy depends largely on the neutrophil count. In non-neutropenic patients, we recommend an echinocandin as the first line treatment option. Patients with susceptible Candida spp. may be switched to fluconazole. Caspofungin or micafungin might be preferred to anidulafungin in the neutropenic patient. L-AmB is a valuable second line treatment option for both groups of patients.

Echinocandins: The Newest Class of Antifungals

Objective:

To review the mechanism of action, antifungal spectrum of activity, pharmacodynamics, pharmacokinetics, clinical efficacy, and safety of the echinocandins.

Data Sources:

A MEDLINE search (1982–May 2009) was conducted for articles published in the English language using the key words caspofungin, micafungin, anidulafungin, and echinocandins.

Study Selection and Data Extraction:

Medicinal chemistry, in vitro, and animal studies, as well as human trials were reviewed for information on the pharmacodynamics, pharmacokinetics, efficacy, and safety of each echinocandin. Clinical trials were reviewed and included to compare and contrast the available echinocandins.

Data Synthesis:

Three echinocandin antifungal agents are currently approved for use in the US: caspofungin, micafungin, and anidulafungin. The echinocandins have a unique mechanism of action, inhibiting β-(1,3)-d-glucan synthase, an enzyme that is necessary for the synthesis of an essential component of the cell wall of several fungi. The echinocandins display fungistatic activity against Aspergillus spp. and fungicidal activity against most Candida spp., including strains that are fluconazole-resistant. The echinocandins have been shown to be efficacious for the treatment of esophageal candidiasis, candidemia, and invasive candidiasis. In addition, caspofungin has demonstrated efficacy as empiric treatment of febrile neutropenia and salvage therapy for the treatment of invasive aspergillosis, and it is the only echinocandin approved for use in pediatric patients. Micafungin is the only echinocandin approved for use as prophylaxis against Candida infections in patients undergoing hematopoietic stem cell transplantation. Overall, resistance to echinocandins is still rare, and all agents are well tolerated, with similar adverse effect profiles and few drug–drug interactions.

Conclusions:

Echinocandins, the newest addition to the arsenal of antifungals, offer potential advantages over other classes of agents. Clinicians should assess their distinguishing characteristics, including route of metabolism, drug interaction profile, and approved indications for use, when determining which agent to include on a formulary.

Increasing incidence of invasive aspergillosis in pediatric hematology oncology patients over the last decade: a retrospective single centre study

There is scanty information about invasive aspergillosis (IA) in the pediatric population. A review of IA at Hospital Infantil Universitario Niño Jesús between 1996 and 2006 was undertaken to analyze incidence, risk factors, and treatment response. Twenty patients were diagnosed with probable or proven IA during the study period, with a cumulative incidence of 1.96%. Incidence was higher in hematopoietic stem cell transplantation (HSCT) recipients: 2.26% (3.5% in allogeneic HSCT and 1.2% in autologous HSCT). A significative increase in IA incidence was observed along the study period (P=0.013), although this increase did not reach signification if only proven cases were compared (P=0.058). Most patients presented multiple risk factors for IA (87% more than 1, and 47% more than 3). The most frequently described risk factor was chemotherapy (90%), after by long-term neutropenia (90%), and corticotherapy (75%). Main locations of the infection were pulmonary (8 patients), cutaneous (3 patients) and intestinal (3 patients). Six patients presented disseminated IA. Initial response to treatment was 55%, although 3 of these cases had a subsequent episode. Global antifungal response, at the end of the follow-up, was 45%. IA-related mortality was 55%. Global mortality was 90%. Only 2 patients (isolated cutaneous IA cases) survived. Seven patients died due to their underlying malignant disease without active fungal disease. Incidence of IA in oncology children is increasing, and in adults. In our experience, IA is a marker of poor outcome even for patients who initially respond to antifungal treatment.

Economic evaluation of voriconazole versus caspofungin for the treatment of invasive aspergillosis in Belgium

OBJECTIVE

To perform an economic evaluation of voriconazole versus caspofungin in first line treatment of invasive aspergillosis (IA). These 2 antifungal drugs have a more favorable toxicity profile than the conventional amphotericin B and have a lower cost than the expensive liposomal/lipid formulation of amphotericin B. No head-to-head comparative study was conducted with voriconazole and caspofungin in IA. Based on the clinical trials of both antifungals, a conservative approach of similar efficacy has been considered.

METHODS

The analysis is based on a simplified cost-minimization model with results from the National Health system RIZIV/INAMI perspective (year 2008). Only limited direct costs were considered, namely the drug cost over the episode of treatment.Treatment duration and patients' weight were key parameters. Their values were obtained from the Belgian observational VORIBEL study (Pfizer data on file) for voriconazole treatment. Treatment duration for caspofungin was derived from the EORTC study where almost 50% of the patients were recruited in Belgian centres. Mean cost and incremental cost were calculated. Univariate sensitivity analyses were carried out on weight, treatment duration as well as on route of administration.

RESULTS

In invasive aspergillosis, the weighted cost per episode of fungal infection was 11.996 pound with voriconazole treatment (voriconazole IV followed by oral voriconazole) and 13.657 pound with caspofungin treatment (intravenous caspofungin only). The incremental saving with voriconazole treatment was 1.661 pound per patient.The cost-saving results of voriconazole were confirmed with varying treatment duration within realistic range. 41% of the patients in the VORIBEL study were fully treated with oral formulation. For these patients a saving of 6.375 pound was achieved with the use of oral voriconazole.

CONCLUSION

Voriconazole is a cost-saving option compared with caspofungin in the treatment of invasive aspergillosis.

Recent advances in antifungal prevention and treatment

Invasive fungal infections are important causes of morbidity and mortality in patients with bone marrow failure syndromes and hematological malignancies, or who are undergoing allogeneic hematopoietic stem cell transplantation (HSCT). Current epidemiological trends indicate a shift toward infections by Aspergillus spp., non-albicans Candida spp., and previously uncommon fungal pathogens that have decreased susceptibility to the available antifungal agents. The last two decades have seen substantial improvements in the clinical, laboratory, and radiological diagnosis of these infections and the development of new antifungal compounds. Progress has been made in establishing disease definitions and paradigms for antifungal intervention and in the design and conduct of interventional clinical trials. Collectively, these advances have led to major but ongoing changes in the management of patients at risk of or being affected by invasive fungal infections. This article reviews current approaches to prevention and treatment of opportunistic fungal infections in immunocompromised patients with hematological disorders and discusses novel approaches to antifungal chemotherapy and adjunctive treatments.

Neutropenic fever syndromes in patients undergoing cytotoxic therapy for acute leukemia and myelodysplastic syndromes

Fever represents the major surrogate of infection in neutropenic cancer patients. A number of neutropenic fever syndromes have been recognized, the causes and significance of which will vary depending upon the clinical context. First neutropenic fever syndromes are typically of bacterial origin, the character of which may be influenced by whether antibacterial chemoprophylaxis has been administered. Persistent neutropenic fevers are documented during the empirical systemic antibacterial therapy for the first neutropenic fever, the cause of which is likely outside the spectrum of activity of the initial therapy. Recrudescent neutropenic fevers, defined by the appearance of a new fever after defervescence of the first fever, are often a function of invasive fungal infection or gram-positive infections outside the spectrum of the initial empirical antibacterial regimen. The myeloid reconstitution syndrome occurs in parallel with neutrophil recovery from aplasia and may not necessarily represent new infection. Recognition of these patterns can help the clinician make better clinical judgments and management plans.

Prevention and treatment of invasive fungal diseases in neutropenic patients

PURPOSE OF REVIEW

Despite advances in the diagnosis and management, invasive fungal diseases contribute substantially to the morbidity and mortality of patients with prolonged neutropenia.

RECENT FINDINGS

Major advances in the prevention, diagnosis, and treatment of invasive fungal diseases have occurred with the introduction of fungal markers and new antifungal agents over the past decade. The newer broad-spectrum azoles and echinocandins, due to their acceptable safety profiles and efficacy, have emerged as valuable options as antifungal prophylaxis and therapy. Empirical antifungal therapy, a strategy in which persistent neutropenic fever triggers the addition of an antifungal agent, remains a common practice. However, the development of fungal diagnostic markers (e.g. galactomannan and beta-glucan assays) combined with radiologic imaging has given potential to more targeted preemptive antifungal strategies.

SUMMARY

With the validation of preemptive strategies in clinical trials, we will likely have evidence-based targeted use of antifungals. PCR-based techniques are also promising tools for preemptive strategies and are undergoing evaluation. Knowledge of host genetic factors may be important in stratifying the risk for fungal disease during periods of high risk.

Pharmacotherapy of Candida Infections with Echinocandins

The classic recommended antifungal agents for the treatment of invasive Candida infections were amphotericin B, a lipid formulation of amphotericin B and fluconazole in both neutropenic or nonneutropenic patients as either primary or alternative therapies. Voriconazole has been recommended when additional coverage for filamentous fungi is needed (e.g. neutropenic patients). More recently and based on well designed comparative clinical trials, the three echinocandins, caspofungin, anidulafungin and micafungin have been added as primary or alternative therapies especially for critically ill or neutropenic patients. In general, the echinocandins are most useful when patients have previously been exposed to an azole or are unstable.

Cost-effectiveness analysis of micafungin versus caspofungin for treatment of systemic Candida infections in the UK

OBJECTIVE

To evaluate the cost-effectiveness of micafungin compared to caspofungin in the treatment of systemic Candida infections (SCIs) in the UK, including invasive candidiasis and candidaemia.

RESEARCH DESIGN AND METHODS

Cost-effectiveness of both echinocandin antifungal drugs was estimated using decision analysis. Response to treatment, resource utilisation, and costs in the model were derived from a phase 3, head-to-head comparative trial. The model includes only data directly related to the treatment of the systemic Candida infection over the study duration (a maximum period of 14 weeks). Transition probabilities were calculated based on the efficacy results from the clinical trial.

MAIN OUTCOME MEASURES

The model's effectiveness outcome is surviving patients who are successfully treated, based on the absence of signs and symptoms, radiographic abnormalities, and culture/histologic evidence associated with the fungal infection. In addition, subgroup analyses were performed to identify cost-effectiveness in several specific patient groups.

RESULTS

The total medical treatment costs for the micafungin group were pound 29,095, which is similar to the total costs for the caspofungin group (pound 29,953). In the micafungin arm 60% of the patients and in the caspofungin arm 58% of the patients were successfully treated and alive. Cost-effectiveness ratio of micafungin was pound 48,771, and of caspofungin pound 52,066 per successfully treated patient. Because the costs are lower and the effectiveness is higher for micafungin in comparison with caspofungin, micafungin is more cost-effective than caspofungin. However, probabilistic sensitivity and subgroup analysis show that the differences cannot be considered significant due to a large variance although micafungin remained the most cost-effective option throughout all but one of the sensitivity analyses.

CONCLUSIONS

Costs and effects of micafungin compare to those of caspofungin in the treatment of systemic Candida infections in the UK. The results indicate that micafungin is cost-effective compared to caspofungin, although the difference was not found to be significant.

Critical care management of cancer patients: cause for optimism and need for objectivity

PURPOSE OF REVIEW

In the 1990s, cancer patients were described as poor candidates for ICU admission on the basis of high mortality rates and management costs. Over the last decade, however, advances in the management of malignancies and organ failures have led to substantial increases in survival. This review discusses current outcomes of critically ill cancer patients and recent insights into prognostic factors. Persistent areas of uncertainty are emphasized.

RECENT FINDINGS

New drugs, diagnostic tools, and management strategies are available for malignancies and organ failures. Survival after ICU admission has increased in patients with solid tumors, hematological malignancies, or autologous hematopoietic cell transplantation. A few patient subgroups remain poor candidates for ICU management (i.e., allogeneic hematopoietic cell transplantation recipients and patients with advanced lung cancer). Careful evaluation of potential benefits from ICU admission is crucial to limit inappropriate ICU admission, nonbeneficial care, and suboptimal resource utilization.

SUMMARY

ICU admission of selected cancer patients leads to meaningful survival. The optimal time of ICU admission needs to be determined, and patient selection criteria by both hemato-oncologists and intensivists should be improved. Long-term studies of overall survival, disease-free survival, and quality of life are needed.

Approaches to the Management of Invasive Fungal Infections in Hematologic Malignancy and Hematopoietic Cell Transplantation

Patients with hematologic malignancy and hematopoietic cell transplant (HCT) recipients are at increased risk for invasive fungal infection (IFI) as a result of immunosuppression or organ damage stemming from their underlying disease, its treatment, or both. Such IFIs can cause significant morbidity and mortality, and the diagnosis and treatment of infected patients frequently are clinically challenging. This article discusses the epidemiology and risk factors for IFI in patients with hematologic malignancy and HCT recipients. The pros and cons of available antifungal agents are discussed, and evolving treatment strategies and recent prophylaxis guidelines from various professional organizations are reviewed. Finally, recommendations are offered for antifungal prophylaxis according to risk group.

A safety and feasibility study comparing an intermittent high dose with a daily standard dose of liposomal amphotericin B for persistent neutropenic fever

A high intermittent dose regimen (group A: 10 mg kg(-1) on day 1, 5 mg kg(-1) on days 3 and 6) was compared with standard dosing (group B: 3 mg kg(-1) per day for 14 days) of liposomal amphotericin B (LAB) for empirical treatment of persistent febrile neutropenia. A total cumulative dose of 1275 mg (group A) and 2800 mg (group B) was administered. Infusion-related adverse drug events, mainly rigors/chills, occurred more frequently with group A (11/45, 24 % infusions) than with group B (12/201, 6 % infusions) (P=0.002), which extended the mean infusion time by 20 min (P=0.001). Creatinine levels were similar in the two regimens: the A : B ratio of the area under the curve for creatinine (AUC(CREATININE)) for days 2-7 was 1.09 (P=0.27) and for days 2-14 was 1.05 (P=0.51). Rises in creatinine were mild (clinical toxicity criteria 1) in all patients with elevations. Hypokalaemia tended to be less severe in group A with a lower proportion of hypokalaemic days [57/143 (39 %) vs 80/137 (58 %), P=0.21], a higher AUC(POTASSIUM) (A : B ratio of 1.06, P=0.12), a lower proportion of patients with hypokalaemia at the end of study (10 vs 61 %, P=0.01) and fewer potassium-supplemented days [12/210 (6 %) vs 41/210 (19.5 %), P<0.1]. There were mildly elevated median levels of serum bilirubin, alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase, which were similar for the two regimens and were usually associated with other co-existing co-morbid conditions. The AUC for these enzymes was also similar in the two groups. No patient had discontinuation of the study drug due to toxicity. Composite success was identical for each regimen (11/15 patients, 73 %). Three of the fifteen patients in group B and none in group A developed invasive fungal infections (IFIs). Beta-D-Glucan levels were similar in both groups for patients without an IFI [AUC(GLUCAN) of 362 and 683 (P=0.36) for groups A and B, respectively]. The rate of defervescence was similar for each regimen (P=0.75). This feasibility study suggests that a short intermittent high-dose course of 10/5/5 mg LAB kg(-1) on days 1, 3 and 6 may be as safe and effective as a standard 14 day course of 3 mg kg(-1) per day, with drug-acquisition cost savings and reduced drug exposure. A larger study is indicated for confirmation of this.

Overview of the changing epidemiology of candidemia

Candida spp. are currently the fourth most common cause of bloodstream infections in US hospitals, and the third most common cause of bloodstream infections in the intensive care unit. Over the last 2 decades there has been a shift towards a greater involvement of non-Candida albicans spp. as the cause of candidemia. Several of these non-albicans spp. (e.g., C. glabrata and C. krusei ) exhibit resistance to traditional triazole antifungals like fluconazole, and cross-resistance with newer triazoles, focusing attention on the first-line use of antifungals such as the echinocandins, which possess improved activity against fluconazole-resistant strains. Recent treatment guidelines from the Infectious Diseases Society of America (IDSA) recommend an echinocandin as primary therapy for nonneutropenic or neutropenic patients with moderately severe to severe candidiasis and for patients at risk for infection with a triazole-resistant strain. However, further improvement in candidemia-associated mortality will only be attainable with the development and validation of new diagnostic tools that will allow earlier detection, discrimination, and treatment of invasive candidiasis. Clinicians should remain vigilant to wider emergence of Candida spp. with echinocandin resistance.

Invasive fungal sinusitis: An effective combined treatment in five haematological patients

Invasive fungal rhinosinusitis (IFR) is a life-threatening infection. Its onset is subtle and a late diagnosis leads to severe complications. Death may occur within a few weeks notwithstanding treatment. We describe a comprehensive pre- and post-operative approach to care for haematological patients with IFR. Five haematological patients with IFR were treated with systemic antifungal therapy and endoscopic surgical debridement of infected tissues, followed by amphotericin-B directly instilled in the sinuses by a new type of ethmoidal drainage. The IFR remitted in all cases; after 32 months of follow-up, three patients are still alive, and two have died of other causes. Two of the patients who experienced IFR progression to the brain at the IFR onset are still alive. The pharmacological and surgical approach with the post-operative local therapy by a new ethmoidal drainage system could support radical antifungal sinus treatment, thus improving the overall survival.

Liposomal amphotericin B: a review of its use as empirical therapy in febrile neutropenia and in the treatment of invasive fungal infections

Liposomal amphotericin B (AmBisome) is a lipid-associated formulation of the broad-spectrum polyene antifungal agent amphotericin B. It is active against clinically relevant yeasts and moulds, including Candida spp., Aspergillus spp. and filamentous moulds such as Zygomycetes, and is approved for the treatment of invasive fungal infections in many countries worldwide. It was developed to improve the tolerability profile of amphotericin B deoxycholate, which was for many decades considered the gold standard of antifungal treatment, despite being associated with infusion-related events and nephrotoxicity. In well controlled trials, liposomal amphotericin B had similar efficacy to amphotericin B deoxycholate and amphotericin B lipid complex as empirical therapy in adult and paediatric patients with febrile neutropenia. In addition, caspofungin was noninferior to liposomal amphotericin B as empirical therapy in adult patients with febrile neutropenia. For the treatment of confirmed invasive fungal infections, liposomal amphotericin B was more effective than amphotericin B deoxycholate treatment in patients with disseminated histoplasmosis and AIDS, and was noninferior to amphotericin B deoxycholate in patients with acute cryptococcal meningitis and AIDS. In adults, micafungin was shown to be noninferior to liposomal amphotericin B for the treatment of candidaemia and invasive candidiasis. Data from animal studies suggested that higher dosages of liposomal amphotericin B might improve efficacy; however, in the AmBiLoad trial in patients with invasive mould infection, there was no statistical difference in efficacy between the standard dosage of liposomal amphotericin B 3 mg/kg/day and a higher 10 mg/kg/day dosage, although the standard dosage was better tolerated. Despite being associated with fewer infusion-related adverse events and less nephrotoxicity than amphotericin B deoxycholate and amphotericin B lipid complex, liposomal amphotericin B use is still limited to some extent by these adverse events. Both echinocandins were better tolerated than liposomal amphotericin B. The cost of liposomal amphotericin B therapy may also restrict its use, but further pharmacoeconomic studies are required to fully define its cost effectiveness compared with other antifungal agents. Based on comparative data from well controlled trials, extensive clinical experience and its broad spectrum of activity, liposomal amphotericin B remains a first-line option for empirical therapy in patients with febrile neutropenia and in those with disseminated histoplasmosis, and is an option for the treatment of AIDS-associated cryptococcal meningitis, and for invasive Candida spp. or Aspergillus spp. infections. Amphotericin B, a macrocyclic, polyene antifungal agent, is thought to act by binding to ergosterol, the principal sterol in fungal cell membranes and Leishmania cells. This results in a change in membrane permeability, causing metabolic disturbance, leakage of small molecules and, as a consequence, cell death. In vitro and in vivo studies have shown that liposomal amphotericin B remains closely associated with the liposomes in the circulation, thereby reducing the potential for nephrotoxicity and infusion-related toxicity associated with conventional amphotericin B. Amphotericin B shows very good in vitro activity against a broad spectrum of clinically relevant fungal isolates, including most strains of Candida spp. and Aspergillus spp., and other filamentous fungi such as Zygomycetes. Liposomal amphotericin B has proven effective in various animal models of fungal infections, including those for candidiasis, aspergillosis, fusariosis and zygomycosis. Liposomal amphotericin B also shows immunomodulatory effects, although the mechanisms involved are not fully understood, and differ from those of amphotericin B deoxycholate and amphotericin B colloidal dispersion. In adult patients with febrile neutropenia, intravenous liposomal amphotericin B has nonlinear pharmacokinetics, with higher than dose-proportional increases in exposure being consistent with reticuloendothelial saturation and redistribution of amphotericin B in the plasma compartment. Liposomal amphotericin B is rapidly and extensively distributed after single and multiple doses, with steady-state concentrations of amphotericin B attained within 4 days and no clinically relevant accumulation of the drug following multiple doses of 1-7.5 mg/kg/day. In autopsy tissue, the highest concentrations of the drug were found in the liver and spleen, followed by the kidney, lung, myocardium and brain tissue. Elimination of liposomal amphotericin B, like that of amphotericin B deoxycholate, is poorly understood; its route of metabolism is not known and its excretion has not been studied. The terminal elimination half-life is about 7 hours. No dosage adjustment is required based on age or renal impairment. In several randomized, double-blind trials (n = 73-1095) in adult and/or paediatric patients, liposomal amphotericin B was effective as empirical therapy or as treatment for confirmed invasive fungal infections, including invasive candidiasis, candidaemia, invasive mould infection (mainly aspergillosis), histoplasmosis and cryptococcal meningitis. All agents were administered as an intravenous infusion; the typical dosage for liposomal amphotericin B was 3 mg/kg/day. Treatment was generally given for 1-2 weeks. Participants in trials evaluating empirical therapy had neutropenia and a persistent fever despite antibacterial treatment and had received chemotherapy or undergone haematopoietic stem cell transplantation. As empirical therapy in adult and paediatric patients, liposomal amphotericin B appeared to be as effective as amphotericin B deoxycholate (approximately 50% of patients in each group achieved treatment success) or amphotericin B lipid complex (approximately 40% of liposomal amphotericin B recipients experienced treatment success). Of note, in the first trial, results of the statistical test to determine equivalence between treatments were not reported. In the second trial, efficacy was assessed as an 'other' endpoint. In another trial, caspofungin was shown to be noninferior to liposomal amphotericin B, with approximately one-third of patients in each group experiencing treatment success. Liposomal amphotericin B was significantly more effective than amphotericin B deoxycholate for the treatment of moderate to severe disseminated histoplasmosis in patients with AIDS, with 88% and 64% of patients, respectively, having a successful response. Liposomal amphotericin B was noninferior to amphotericin B deoxycholate for the treatment of cryptococcal meningitis in terms of mycological success. Micafungin therapy was shown to be noninferior to liposomal amphotericin B for the treatment of adult patients with candidaemia or invasive candidiasis. In a substudy in paediatric patients, which was not powered to determine noninferiority, liposomal amphotericin B was as effective as micafungin for the treatment of candidaemia or invasive candidiasis. In this patient population, within each trial, 90% of adult patients and approximately three-quarters of paediatric patients in both treatment groups experienced a successful response. In patients with invasive mould infection (mainly aspergillosis), there was no difference in efficacy between a higher dosage of liposomal amphotericin B (10 mg/kg/day) and the standard dosage (3 mg/kg/day), with 46% and 50% of patients experiencing a favourable overall response. In well designed clinical trials, liposomal amphotericin B was generally at least as well tolerated as other lipid-associated formulations of amphotericin B and better tolerated than amphotericin B deoxycholate in adult and paediatric patients. Compared with other amphotericin B formulations, liposomal amphotericin B treatment was associated with a lower incidence of infusion-related adverse events and nephrotoxicity. A higher than recommended dosage of liposomal amphotericin B (10 mg/kg/day) was associated with an increased incidence of nephrotoxicity compared with the standard dosage (3 mg/kg/day), although the incidence of infusion-related reactions did not differ between treatment groups. In general, liposomal amphotericin B treatment was not as well tolerated as echinocandin therapy in well designed clinical trials. As empirical therapy or for the treatment of confirmed invasive fungal infections in adult patients, liposomal amphotericin B recipients experienced more infusion-related events and nephrotoxicity than caspofungin or micafungin recipients. There was no difference in the incidence of these adverse events between the liposomal amphotericin B and micafungin groups in a study in paediatric patients.

[Future role of micafungin in the treatment of invasive mycoses caused by filamentous fungi]

BACKGROUND

Micafungin is a echinocandin. It inhibits beta-1,3-D-glucan synthesis, thus achieving fungicidal activity against virtually all Candida spp., including those resistant to fluconazole, and fungistatic activity against Aspergillus spp., as well as several but not all pathogenic molds. Results from in vitro studies, animal models, small clinical trials, hint at possible future indications such as invasive aspergillosis and empirical viantifungal therapy, although currently there is little information published.

AIMS

To describe published data of micafungin as treatment against invasive mold infections, specially analysing its role in the inmunodepressed host and critical care setting.

METHODS

A systematic review of literature using the principal medical search engines was performed. Terms such as micafungin, aspergillosis, zygomycosis, invasive fungal infections, emerging fungal infections, antifungal treatment or therapy, antifungal prophylaxis, empiric or pre-emptive therapy were crossed. Febrile neutropenia patients were excluded.

RESULTS

Several studies in these setting were identified and were described in this review. Although there were no blinded randomized clinical trials published, treatment or prophylaxis of invasive aspergillosis and other invasive mould infections with micafungin described in open clinical studies were analyzed.

CONCLUSIONS

Micafungin could play a future important role as a primary or rescue therapy, alone or in combination, in the treatment or prophylaxis of invasive fungal infections caused by moulds. New randomized clinical trials are needed to confirm their efficacy.

Economic impact of caspofungin as compared with liposomal amphotericin B for empirical therapy in febrile neutropenia in Australia

BACKGROUND

In a major clinical trial, caspofungin was as efficacious as liposomal amphotericin B (LAmB) for empirical therapy in febrile neutropenia. The current study sought to evaluate the economic impact of caspofungin as compared with LAmB for febrile neutropenia in Australia.

METHODS

A decision analytic model was developed to capture the downstream consequences of the empirical antifungal therapy. The main outcomes were success, breakthrough infection, persistent baseline infection, persistent fever, premature discontinuation and death. Underlying transition probabilities and treatment patterns were derived directly from trial data. Resource use was estimated using an expert panel. Cost inputs were obtained from the latest Australian representative sources. The perspective adopted was that of the Australian hospital system. Uncertainty and sensitivity analyses were undertaken via Monte Carlo simulation.

RESULTS

Caspofungin was associated with a net cost saving of AU$7245 (12.6%) per patient over LAmB (AU$50 267 versus AU$57 512). A similar trend was observed with cost per success and death prevented (AU$24 169 and AU$7270, respectively). Caspofungin dominated LAmB as it resulted in higher efficacy and lower costs when compared with LAmB. Persistent fever was the main contributing clinical outcome to the therapeutic costs of both antifungals. The results were most sensitive to therapy duration. Monte Carlo simulation suggested a 99.8% chance for LAmB to cost more than caspofungin.

CONCLUSIONS

This is the first economic study to evaluate the place of caspofungin as empirical therapy in Australia. Caspofungin is more cost-beneficial than LAmB, which contradicts the current Australian guidelines of recommending LAmB as the first choice for empirical therapy.

Impact of PCR-based diagnosis of invasive pulmonary aspergillosis on clinical outcome

The mortality rate of 60-90% in invasive pulmonary aspergillosis (IPA) is partly explained by diagnostic delay due to the limitation of current diagnostic tests. We assessed the influence of Aspergillus species (ASP) DNA detection by PCR from bronchoalveolar lavage (BAL) fluid, a new tool for diagnosing IPA, on the outcome of this disease in immune-compromised patients. The study population comprised 107 consecutive patients with hematological malignancies from a single medical center with IPA diagnosed between 1998 and 2005. Clinical variables and mortality rates were compared between two groups diagnosed according to traditional criteria without and with PCR-based ASP DNA detection in BAL fluid. The overall mortality rate during the study period was 38.3%. The addition of PCR to the diagnostic criteria shifted 31 patients from possible to probable IPA. Patients diagnosed with probable IPA according to traditional microbiological methods had significantly higher mortality rates compared to their counterparts who had in addition a PCR-based diagnosis (80 vs 35.6%, P=0.003). This study demonstrates that PCR-based ASP DNA detection for a diagnosis of IPA from BAL fluid has a significant effect on the outcome of patients with IPA, probably related to earlier diagnosis.

Antifungal activities of natural and synthetic iron chelators alone and in combination with azole and polyene antibiotics against Aspergillus fumigatus

Antifungal effects of iron chelators (lactoferrin, deferoxamine, deferiprone, and ciclopirox) were tested alone and in combination with antifungal drugs against Aspergillus fumigatus B5233 conidia. Lactoferrin, ciclopirox, and deferiprone inhibited whereas deferoxamine enhanced fungal growth. Antifungal synergy against conidia was observed for combinations of ketoconazole with ciclopirox or deferiprone, lactoferrin with amphotericin B, and fluconazole with deferiprone. Iron chelation alone or combined with antifungal drugs may be useful for prevention and treatment of mycosis.

Clinical practice guidelines for the management of candidiasis: 2009 update by the Infectious Diseases Society of America

Guidelines for the management of patients with invasive candidiasis and mucosal candidiasis were prepared by an Expert Panel of the Infectious Diseases Society of America. These updated guidelines replace the previous guidelines published in the 15 January 2004 issue of Clinical Infectious Diseases and are intended for use by health care providers who care for patients who either have or are at risk of these infections. Since 2004, several new antifungal agents have become available, and several new studies have been published relating to the treatment of candidemia, other forms of invasive candidiasis, and mucosal disease, including oropharyngeal and esophageal candidiasis. There are also recent prospective data on the prevention of invasive candidiasis in high-risk neonates and adults and on the empiric treatment of suspected invasive candidiasis in adults. This new information is incorporated into this revised document.

A prospective, multicenter study of caspofungin for the treatment of documented Candida or Aspergillus infections in pediatric patients

OBJECTIVE

We evaluated the safety, tolerability, and efficacy of caspofungin in pediatric patients with invasive aspergillosis, invasive candidiasis, or esophageal candidiasis.

METHODS

This was a multicenter, prospective, open-label study in children 3 months to 17 years of age with proven or probable invasive aspergillosis, proven invasive candidiasis, or proven esophageal candidiasis. All of the patients received caspofungin 70 mg/m(2) on day 1, followed by 50 mg/m(2) per day (maximum: 70 mg/day), as primary or salvage monotherapy. Favorable response was defined as complete resolution of clinical findings and microbiologic (or radiographic/endoscopic) eradication (complete response) or significant improvement in these parameters (partial response). Efficacy was assessed at the end of caspofungin therapy in patients with a confirmed diagnosis who received >/=1 dose of caspofungin. The primary safety evaluation was the proportion of patients with clinical or laboratory drug-related adverse events.

RESULTS

Of the 49 patients enrolled, 3 were <2 years of age, 30 were 2 to 11 years of age, and 16 were 12 to 17 years of age. Forty-eight patients had confirmed disease: invasive aspergillosis (10), invasive candidiasis (37), and esophageal candidiasis (1). Eight of 10 patients with invasive aspergillosis had pulmonary involvement; 34 of 37 patients with invasive candidiasis had candidemia. Caspofungin was given for 2 to 87 days. Success at end of therapy was achieved in 5 of 10 patients with invasive aspergillosis, 30 of 37 with invasive candidiasis, and 1 of 1 with esophageal candidiasis. One patient (invasive candidiasis) relapsed during the 28-day follow-up period. Drug-related clinical or laboratory adverse events occurred in 27% and 35% of patients, respectively. There were no serious drug-related adverse events or discontinuations of caspofungin because of toxicity.

CONCLUSIONS

Caspofungin was generally well tolerated in pediatric patients aged 6 months through 17 years. Efficacy outcomes in patients with invasive aspergillosis or invasive candidiasis were consistent with previous adult studies in these indications.

Therapeutic strategies for invasive fungal infections in neonatal and pediatric patients

Invasive Candida and Aspergillus infections are the most commonly encountered fungal infections. They appear to be life threatening in the setting of profound immunosuppression, whereas cases that are resistant to antifungal therapy are occasionally encountered. Novel antifungal triazole and echinocandin agents appear to exhibit good activity as first-line or salvage therapy, whereas the use of amphotericin B formulations is particularly valuable in neonates. Significant differences in toxicity have been demonstrated among various antifungal agents with in vitro activity from available comparative data on fungal infections in children: however, no clear difference in treatment efficacy has been demonstrated. However, very little data are available about neonates. Host factors and responsible fungal species most frequently guide the choice of therapy.

Comparative cost-effectiveness of posaconazole versus fluconazole or itraconazole prophylaxis in patients with prolonged neutropenia

PURPOSE

A cost-effectiveness analysis was performed to investigate the financial impact of using posaconazole versus fluconazole or itraconazole prophylaxis in patients with prolonged neutropenia.

METHODS

A decision-analytic model was developed from a hospital perspective based on the use of posaconazole versus fluconazole or itraconazole prophylaxis in patients with prolonged neutropenia (i.e., longer than 7-10 days). Data reported in a multicenter study, medication-cost information, and reports of costs to treat invasive fungal infections were used to accurately populate the model. Sensitivity analyses enhanced the robustness of the model through variation of all probabilities and costs.

RESULTS

In the base case, patients initiated on posaconazole displayed a 45% reduction in overall cost as compared with patients initiated on fluconazole or itraconazole ($3051 versus $5529, respectively). Sensitivity analyses determined that univariate changes in all model variables, including medication cost, duration of therapy, and cost of treating invasive fungal infections, did not impact overall results. A Monte Carlo simulation analysis found that use of posaconazole remains the best overall prophylactic strategy when taking into consideration the potential variance in all model assumptions. Posaconazole dominated the use of fluconazole or itraconazole because of previously demonstrated lower incidence of breakthrough fungal infections and lower overall treatment cost.

CONCLUSION

The decision model indicated that use of posaconazole as prophylaxis in patients with prolonged neutropenia should result in lower overall treatment costs relative to the cost of fluconazole or itraconazole.

Clinical indications for newer antifungal agents

Recent years have seen the release of multiple new systemic antifungal agents, significantly increasing options for the treatment of most serious fungal infections. Newly available drugs include those in the echinocandin class, including caspofungin, micafungin, and anidulafungin, as well as the newer generation triazoles, voriconazole and posaconazole. Ordering of these agents is variably restricted, depending on a given institution's policies, and all are costly. In this review we examine the available evidence and outline the role of newer antifungal medications in several common and/or important situations, including invasive and mucocutaneous Candida infection, febrile neutropenia, invasive aspergillosis, zygomycosis, and endemic mycoses.

Antibiotic management of sepsis: current concepts

BACKGROUND

The development of guidelines for sepsis management has improved disease survival and reduced treatment costs. Adequate antibiotic therapy is the cornerstone of sepsis treatment. Specific rules should be established in every institution according to its profiles.

OBJECTIVES

To review the current knowledge about the best drugs to be used as empiric treatment for sepsis based on their clinical efficacy and costs.

METHODS

Medline 1950 - 2008 was searched using the following terms: sepsis, organ failure, system failure, SIRS, septic shock, antibiotic, pneumonia, urinary tract infection, urosepsis, catheter-related infection, bloodstream, abdominal infection, and surgical wound.

RESULTS/CONCLUSION

For most septic shock patients, monotherapy is adequate and treatment should be initiated in the first hour after first sepsis-induced organ dysfunction. The drug of choice varies in different situations and choosing the right antibiotic enables better survival, fewer complications and shorter stays in intensive care.

Pharmacokinetics and safety of caspofungin in older infants and toddlers

Although information about the efficacy and safety experience with caspofungin at 50 mg/m(2) daily is available for children and adolescents, the dosing regimen in infants and toddlers 3 to 24 months of age has yet to be established. We studied the pharmacokinetics and safety of caspofungin at 50 mg/m(2) once daily in nine patients 10 to 22 months (median, 13 months) of age with fever and neutropenia who received caspofungin once daily for 2 to 21 (mean, 9.3) days. Plasma caspofungin concentrations were measured by high-performance liquid chromatography assay on days 1 and 4. On day 4, the area under the curve from 0 to 24 h (AUC(0-24)) was 130.3 microg-h/ml, the peak concentration (C(1)) was 17.2 microg/ml, and the trough concentration (C(24)) was 1.6 microg/ml. The day 4 geometric mean ratios (GMRs) and 90% confidence interval (CI) for these parameters in infants/toddlers relative to adults were 1.26 (1.06, 1.50), 1.83 (1.57, 2.14), and 0.81 (0.64, 1.04), respectively. Relative to children (2 to 11 years of age), the day 4 GMRs (and 90% CI) were 1.13 (0.89, 1.44), 1.10 (0.85, 1.42), and 1.12 (0.72, 1.76), respectively. The harmonic mean elimination phase t(1/2) in infants/toddlers (8.8 h) was reduced approximately 33% relative to adults (13.0 h) but was similar to that in children (8.2 h). Clinical adverse events occurred in seven patients (78%); none were considered drug related. Laboratory adverse events occurred in five patients (56%) and were considered drug related in three (33%). There were no infusion-related events or discontinuations due to toxicity. Caspofungin at 50 mg/m(2) daily was well tolerated in infants and toddlers; the AUC and caspofungin C(24) were generally comparable to those in adults receiving caspofungin at 50 mg daily.

Newer antifungal agents for invasive fungal infections in patients with haematological malignancy

Since 2001 five new systemically administered antifungal agents have been approved for clinical use. This represents a major advance for antifungal therapy in haematological malignancy patients undergoing chemotherapy or haematopoietic stem cell transplant (HSCT). The echinocandins are a new class of antifungals with a novel mode of action. Capsofungin has already established itself as a valuable therapy for candidaemia and salvage therapy of invasive aspergillosis. Although both anidulafungin and micafungin are approved for treatment of candidiasis, their role in invasive aspergillosis requires more clinical trial evaluation. Of the two newer triazoles, voriconazole has been recommended in international guidelines as primary therapy for acute invasive aspergillosis. Posaconazole has a broad spectrum of activity in vitro and a potentially key role in antifungal prophylaxis in high-risk HSCT recipients and during prolonged neutropenia. Although some of these drugs have important interactions with other medications, and potential toxicities, they are safer to use and more efficacious than amphotericin B deoxycholate. Their arrival gives more choices to treat rarer mycoses and will facilitate clinical trial assessment of combination therapy of aspergillosis where single agent therapy gives less than 50% success rates.

Current antimicrobial usage for the management of neutropenic fever in Korea: a nationwide survey

A nationwide questionnaire-based survey was performed to evaluate the current clinical practices for the management of neutropenic fever in hematology units and hematopoietic stem cell transplantation (HSCT) centers throughout Korea. A 86.9% response rate was obtained from a total of 46 doctors and practical policies of the 33 sites were analysed. Approximately 42.4% and 84.8% of the sites responded that they used oral fluoroquinolone as prophylaxis for neutropenic patients receiving chemotherapy and HSCT, respectively. Additionally, 42.4% of the sites responded that they used antifungal prophylaxis in the chemotherapy groups whereas 90.9% of the sites responded that they used antifungal prophylaxis in HSCT recipients. Approximately half of the responding sites prescribed combination regimen with 3rd or 4th cephalosporin plus aminoglycoside as a first-line therapy. Most of the sites considered persistent fever for 2-4 days or aggravated clinical symptoms for 1-2 days as failure of the first-line regimen, and they changed antibiotics to second-line regimens that varied widely among the sites. Twenty-seven sites (84.4%) responded that they considered adding an antifungal agent when fever persisted for 5-7 days despite antibacterial therapy. Amphotericin B deoxycholate was preferred as a first-line antifungal, which was probably due to the limitations of the national health insurance system. The role of oral antibiotics in the management of neutropenic fever still accounted for a small portion. To the best of our knowledge, this survey is the first report to examine the practical policies currently in place for the management of neutropenic fever in Korea and the results of this survey may help to establish a Korean guideline in the future.

Febrile neutropenia

This review summarizes the current status and diagnostic-therapeutic challenges in febrile neutropenia. Patients with neutropenia-associated infections have a poor prognosis. A large meta-analysis of trials assessing prophylactic antibiotics has shown significant survival benefits; clinical significance of resistance is unclear. Administering broad-spectrum antibiotics to established febrile neutropenic patients has become selective, vancomycin is withheld unless absolutely necessary, and low-risk patients are identified with biological markers. Such patients are now managed with oral antibiotics at home or even without antibiotics. Protracted prolonged neutropenia is the setting par excellence for invasive fungal infections. Conventional amphotericin B administered to such risk patients reduces the incidence of fungal infections. New antifungal drugs have heightened efficacy and lowered toxicity. Novel antifungal diagnostic tests include imaging, particularly the CT "halo" sign (aspergillosis), and serology (glucan, galactomannan), and provide earlier diagnosis and treatment and better outcomes. Negative tests may indicate withholding antifungal therapy. High intermittent dosing of liposomal amphotericin B seems as safe and as effective as standard dosing regimens, but at half the drug acquisition cost. The use of nonantibiotic agents has offered alternative management strategies. Recombinant interleukin-11 reduces bacteremia, through a cytoprotective mechanism on the gut. rhIL-11 releases C-reactive protein and causes shedding of soluble TNF receptor-1, modulating the immunological milieu and the systemic inflammatory response. Other candidate molecules include RANTES and long-pentraxin 3. Recombinant growth factors reduce febrile episodes, permitting completion of chemotherapy, increase overall survival, and minimize infection mortality.

Double-blind active-control trials: beware the comparator you keep

The indirect impact of the known comparator drug in double-blind comparative clinical trials of novel agents is underappreciated, despite its potentially pernicious effects. This hypothesis-generating analysis illustrates potential spillover effects of a comparator (amphotericin) in the evaluation of the first member (caspofungin) of a novel class (echinocandins) of antifungal drugs. Reported rates of drug-related fever in the first 3 studies of caspofungin for the treatment of mucosal candidiasis in patients with advanced human immunodeficiency virus infection were retrospectively analyzed. We compared patients who received 50 mg of caspofungin per day in a double-blind trial that used fluconazole as the comparator with patients who received the corresponding dosage in 2 similar earlier studies that used amphotericin as the comparator. With respect to the incidence of drug-related fever, the difference between the concurrent caspofungin and fluconazole groups was less than the difference between caspofungin groups from studies that used different comparators. In phase II/III blinded, active-control trials, the reporting of adverse experiences attributed to a first-in-class drug might be confounded to a variable degree by expectations regarding a well-known comparator.