卡泊芬净治疗中国成年人侵袭性念珠菌病和食管念珠菌病的安全性、耐受性及疗效的非对照、多中心、开放性研究

目的评价卡泊芬净注射剂治疗中国成年人侵袭性念珠菌病和食管念珠菌病的疗效及安全性。方法本研究为非对照、多中心、开放性临床研究,入选对象为年龄≥18岁,确诊为侵袭性念珠菌病或食管念珠菌病需要进行抗真菌治疗的中国成人患者。采用卡泊芬净静脉给药,每日50 mg,首日采用70 mg负荷剂量。在最后一次血液或其他正常无菌部位培养阳性后继续治疗至少14 d。食管念珠菌病患者每日50 mg,疗程至少7 d,症状缓解后继续治疗72 h。结果共入选63例患者,包括侵袭性念珠菌病60例,食管念珠菌病3例,其中安全性分析集（SS）63例,全分析集（FAS）63例,符合方案集（PPS）50例。SS 63例患者中,14例发生19例次严重不良事件,均与研究药物无关;发生与药物有关的非严重不良事件31例73例次,其中4例同时发生临床不良事件和实验室指标异常;8例发生12例次临床不良事件,主要为皮疹等,其中91.7%（11/12）属轻、中度。27例发生实验室指标异常,主要为ALT等肝酶升高、血钾降低等。与研究药物相关的不良事件总发生率为49.2%（31/63）,其中临床不良事件发生率为12.7%（8/63）,实验室指标异常发生率为42.9%（27/63）。1例因不良事件终止治疗,占1.6%（1/63）。FAS和PPS中的总有效率分别为58.1%（36/62）和70.0%（35/50）。FAS中,侵袭性念珠菌病的有效率为57.6%（34/59）,食管念珠菌病为2/3。PPS中,侵袭性念珠菌病的有效率为68.8%（33/48）,食管念珠菌病为3/3。结论卡泊芬净治疗中国成年人侵袭性念珠菌病和食管念珠菌病临床不良反应大多为轻、中度,患者可耐受。卡泊芬净可有效治疗中国成年人侵袭性念珠菌病和食管念珠菌病。     

Caspofungin treatment in severely ill, immunocompromised patients: a case-documentation study of 118 patients

BACKGROUND: Caspofungin has shown efficacy in empirical antifungal therapy in neutropenic patients, refractory invasive Aspergillus infections and invasive candidiasis. Here we report the currently largest series of patients treated with caspofungin outside clinical trials. METHODS: Centres in Germany that were known to treat patients with invasive fungal infections were asked to fill out detailed questionnaires for all patients treated with caspofungin. No effort was made to influence the decision to use caspofungin. RESULTS: A total of 118 patients were evaluable (median age 48 years, interquartile range 38-58), out of which 41 (35%) suffered from acute leukaemia, 31 (26%) had allogeneic stem cell transplants, 16 (14%) lymphoma or myeloma, 8 (7%) autologous stem cell transplants and 22 (19%) other causes for immunosuppression. One hundred and six patients were evaluable for efficacy out of which 68 (64%) patients achieved a complete or partial remission. A total of 81 out of 115 (70%) patients were alive 30 days after the end of caspofungin therapy. Response rates were similar in proven (20/32, 63%) and probable (27/46, 59%) infections, in neutropenic patients (41/55, 75%) and in patients who were (44/70, 63%) or were not (24/36, 67%) refractory to antifungal pre-treatment. The response rate in mechanically ventilated patients was 29% (7/24). Caspofungin was well tolerated, even in 14 patients, who were concomitantly treated with ciclosporin A, no drug-related elevations of bilirubin, alanine aminotransferase or creatinine were found. CONCLUSIONS: This open case study of severely ill patients with invasive fungal infections demonstrates both excellent efficacy and very low toxicity of caspofungin.     

Second-line therapy with caspofungin for mucosal or invasive candidiasis: results from the caspofungin compassionate-use study

OBJECTIVES: To prospectively assess the efficacy and safety of caspofungin as second-line therapy for mucosal or invasive candidiasis in patients enrolled in the caspofungin compassionate-use study. MATERIALS AND METHODS: Thirty-seven patients with mucosal or invasive candida infections (17 oesophageal, four oropharyngeal and 16 invasive candidiasis) were enrolled in the caspofungin compassionate-use study. All patients were refractory to or intolerant of intravenous amphotericin B or lipid amphotericin formulation(s). Efficacy was assessed at the end of intravenous caspofungin therapy based on clinical (and, where appropriate, microbiological) response. RESULTS: HIV was the most common (91%) risk factor in patients with mucosal candidiasis; patients with invasive candidiasis commonly had acute leukaemia/lymphoma (50%) or diabetes mellitus (31%). Most patients with mucosal candidiasis (91%) and invasive candidiasis (94%) were refractory to >/=1 antifungal agent(s). A favourable response was noted in 82% (14/17) with oesophageal candidiasis, 100% (4/4) with oropharyngeal candidiasis and 87% (13/15) with invasive candidiasis. Caspofungin was generally well tolerated; one serious drug-related adverse event was reported. CONCLUSION: In this study, caspofungin was an effective alternative for patients with refractory candida infections.     

Caspofungin for prevention of intra-abdominal candidiasis in high-risk surgical patients

Purpose  Thirty to forty percent of patients with recurrent gastrointestinal perforation/anastomotic leakage or acute necrotizing pancreatitis develop intra-abdominal invasive candidiasis (IC). A corrected Candida colonization index (CCI) ≥0.4 is a powerful predictor of IC. Fluconazole prevents intra-abdominal IC in this setting, but azole-resistant Candida species are emerging. The aim of this study was to explore the efficacy and safety of caspofungin for prevention of intra-abdominal IC in high-risk surgical patients. Methods  Prospective non-comparative single-center study in consecutive adult surgical patients with recurrent gastrointestinal perforation/anastomotic leakage or acute necrotizing pancreatitis. Preventive caspofungin therapy (70 mg, then 50 mg/day) was given until resolution of the surgical condition. Candida colonization index and CCI, occurrence of intra-abdominal IC and adverse events were monitored. Results  Nineteen patients were studied: 16 (84%) had recurrent gastrointestinal perforation/anastomotic leakage and 3 (16%) acute necrotizing pancreatitis. The median duration of preventive caspofungin therapy was 16 days (range 4–46). The colonization index decreased significantly during study therapy, and the CCI remained <0.4 in all patients. Caspofungin was successful for prevention of intra-abdominal IC in 18/19 patients (95%, 1 breakthrough IC 5 days after inclusion). No drug-related adverse event requiring caspofungin discontinuation occurred. Conclusion  Caspofungin may be efficacious and safe for prevention of intra-abdominal candidiasis in high-risk surgical patients. This needs to be further investigated in randomized trials. This study has been partially presented as poster # M-1163 at the 47th ICAAC (Interscience Conference on Antimicrobial Agents and Chemotherapy), Chicago, 17–20 September 2007.     

Pharmacokinetics, safety, and tolerability of caspofungin in children and adolescents

Caspofungin is a parenteral antifungal that inhibits beta-1,3-D-glucan synthesis. Although licensed for adult use, the appropriate caspofungin dosing regimen in pediatric patients is not yet known. We therefore investigated the pharmacokinetics and safety of caspofungin in pediatric patients. Thirty-nine children (ages 2 to 11 years) and adolescents (ages 12 to 17 years) with neutropenia were administered caspofungin using either a weight-based regimen (1 mg/kg of body weight/day) or a body surface area regimen (50 mg/m2/day or 70 mg/m2/day). Plasma samples for caspofungin profiles were collected on days 1 and 4. These results were compared to those from adults treated with either 50 or 70 mg/day for mucosal candidiasis. In children receiving 1 mg/kg/day (maximum, 50 mg/day), the area under the concentration-time curve over 24 h (AUC(0-24)) was significantly smaller (46% after multiple doses) than that observed in adults receiving 50 mg/day (P < 0.001). In children and adolescents receiving 50 mg/m2/day (maximum, 70 mg/day), the AUC(0-24) following multiple doses was similar to that for the exposure in adults receiving 50 mg/day. The AUC(0-24) and concentration trough (at 24 h) in pediatric patients receiving the 50-mg/m2 daily regimen were consistent across the range of ages. Caspofungin was generally well tolerated in this study. None of the patients developed a serious drug-related adverse event or were discontinued for toxicity. These results demonstrate that caspofungin at 1 mg/kg/day in pediatric patients is suboptimal. Caspofungin administration at 50 mg/m2/day provides a comparable exposure to that of adult patients treated with 50 mg/day.     

Randomized, double-blind, multicenter study of caspofungin versus amphotericin B for treatment of oropharyngeal and esophageal candidiases.

Caspofungin is an antifungal agent of the novel echinocandin class. We investigated its efficacy, safety, and tolerability as therapy for oropharyngeal and/or esophageal candidiasis in a phase II dose-ranging study. Patients were randomized in a double-blind manner to receive either caspofungin acetate (35, 50, or 70 mg) or amphotericin B (0.5 mg/kg of body weight) intravenously once daily for 7 to 14 days. A favorable response required both complete resolution of symptoms and quantifiable improvement of mucosal lesions 3 to 4 days after discontinuation of study drug. Efficacy was assessed using a modified intent-to-treat analysis. No hypothesis testing of efficacy was planned or performed. Of 140 enrolled patients, 63% had esophageal involvement and 98% were infected with the human immunodeficiency virus (HIV) (median CD4 count, 30/mm(3)). A modestly higher proportion of patients in each of the caspofungin groups (74 to 91%) achieved favorable responses compared to amphotericin B recipients (63%), but there was considerable overlap in the 95% confidence intervals surrounding these point estimates. Similar trends were found in the subgroups with esophageal involvement, a history of fluconazole failure, and CD4 counts of < or =50/mm(3). A smaller proportion of patients receiving any dose of caspofungin experienced drug-related adverse events compared to patients given standard doses of conventional amphotericin B (P < 0.01). Caspofungin provided a generally well-tolerated parenteral therapeutic option for HIV-infected patients with oropharyngeal and/or esophageal candidiasis in this study.     

Effect of nikkomycin Z and 50% human serum on the killing activity of high-concentration caspofungin against Candida species using time-kill methodology

Caspofungin and nikkomycin Z (NIK) efficacy alone and in combination were tested against seven Candida species showing or not showing paradoxical growth (PG) against caspofungin in time-kill test in RPMI-1640. Selected isolates against caspofungin and NIK were also tested in 50% serum. PG was always eliminated by NIK as well as by serum. In the serum, 1 and 16 μg/ml caspofungin yielded 0.14-4.0 and 0.34-4.0 log CFU decreases from the starting inocula for C. albicans, C. glabrata, C. tropicalis, and C. dubliniensis, respectively. CFU decrease (0.10-2.08 log) at 16 μg/ml, but not at lower caspofungin concentration was noted against C. parapsilosis, C. orthopsilosis, and C. metapsilosis. One C. parapsilosis isolate was not inhibited even by 16 μg/ml caspofungin. Caspofungin against C. albicans, C. glabrata, C. tropicalis, and C. dubliniensis maintained its activity in serum at even 1 μg/ml concentration. PG seems to an in vitro phenomenon, without clinical relevance.     

Caspofungin for the treatment of less common forms of invasive candidiasis

OBJECTIVES: Caspofungin has demonstrated efficacy in invasive candidiasis. However, in a comparative study, most patients (>83%) had candidaemia. Therefore, we performed a study in patients with non-fungaemic invasive candidiasis. PATIENTS AND METHODS: Adults with proven non-fungaemic invasive candidiasis or probable chronic disseminated candidiasis (CDC) received caspofungin primary or salvage monotherapy. Most patients received 50 mg daily following a 70 mg loading dose. Patients with endocarditis, osteomyelitis or septic arthritis received caspofungin at 100 mg daily and were allowed dose escalation up to 150 mg. Primary efficacy endpoint was the overall response at end of caspofungin therapy. A favourable overall response required complete resolution of symptoms and either eradication of Candida or radiographic resolution. RESULTS: All 48 patients enrolled had confirmed infection and received>or=1 dose of caspofungin. At study entry, 8% were neutropenic. The mean APACHE II score was 14.3. Most infections were due to Candida albicans (60%) or Candida glabrata (14%). The overall success at end of caspofungin therapy was 81%. Success by site of infection was as follows: peritonitis 77% (10/13), abdominal abscess 89% (8/9), CDC 88% (7/8), osteomyelitis/septic arthritis 100% (4/4), endocarditis 33% (1/3) and multiple sites 75% (6/8). Outcomes were similar across Candida spp. None of the patients had a serious drug-related adverse event or discontinued caspofungin due to toxicity. Overall mortality until 12 week follow-up was 23%. CONCLUSIONS: In deep-seated invasive candidiasis, including peritonitis, abdominal abscesses, CDC and arthritis, caspofungin was effective and safe at regular doses and up to 100 mg daily.     

Caspofungin: an echinocandin antifungal agent

BACKGROUND: The mainstays of treatment for nosocomial fungal infections have been amphotericin B and azole derivatives. Caspofungin acetate is a new echinocandin antifungal agent with a mechanism of action that targets a structural component of the fungal cell wall. OBJECTIVE: This article describes the pharmacologic properties and potential clinical usefulness of caspofungin. METHODS: Relevant information was identified through searches of MEDLINE (1966-September 2001). Iowa Drug Information Service (1966-September 2001), and International Pharmaceutical Abstracts (1970-September 2001), as well as meeting abstracts of the Infectious Diseases Society of America and the Interscience Conference on Antimicrobial Agents and Chemotherapy (1996-2001), using the terms caspofungin, MK-0991, pneumocandin, echinocandin, candin, and beta-(1,3)-glucan inhibitor. RESULTS: In vitro, caspofungin exhibits antifungal activity against an array of clinically important yeasts and molds, including Candida and Aspergillus spp. The proposed susceptibility breakpoint for caspofungin against Candida spp, the most common cause of nosocomial fungal infections, is a minimum inhibitory concentration of < or =1 microg/mL. In humans, caspofungin has a volume of distribution of 9.67 L, is extensively bound to albumin (97%), has a plasma elimination half-life of 9 to 11 hours, and is metabolized to inactive metabolites in the liver. Dose adjustment based on age, sex, race, or renal function does not appear to be necessary, although patients with moderate hepatic insufficiency (Child-Pugh score 7-9) should receive a lower maintenance dose. The results of clinical trials, although somewhat preliminary, suggest that caspofungin is effective in the treatment of esophageal and oropharyngeal candidiasis and invasive aspergillosis. When combined with other antifungal agents, caspofungin produces a synergistic or additive effect against a variety of clinically important fungi. The most commonly reported adverse events with caspofungin have included fever, infusion-related reactions, headache, nausea, elevations in liver transaminase levels, and histamine-type reactions. The recommended dosage in adults is 70 mg IV on day 1 followed by 50 mg/d, with the duration of treatment depending on the severity of the patient's underlying condition and the clinical response. CONCLUSION: Although additional studies are needed, caspofungin appears to be a promising agent for the treatment of patients with difficult-to-treat or life-threatening fungal infections.     

Factors influencing caspofungin plasma concentrations in patients of a surgical intensive care unit

BACKGROUND: Co-morbidity, medical and surgical interventions often cause alterations to drug plasma concentrations and pharmacokinetic parameters in critically ill patients. In the present study, we investigated parameters influencing plasma caspofungin concentrations in patients of a surgical intensive care unit (SICU). METHODS: In a monocentre open study, caspofungin trough concentrations (C(24)) were determined for a group of SICU patients. A linear-mixed model was then used to assess factors influencing caspofungin plasma concentrations. RESULTS: A total of 40 SICU patients were enrolled. Age and body weight ranged from 22 to 76 years and 47 to 108 kg, respectively. All participants received a caspofungin loading dose of 70 mg and a maintenance dose of 50 mg/day. The median duration of therapy was 10 days. Caspofungin C(24) in SICU patients varied more than those determined for healthy subjects reported in previous studies (0.52-4.08 microg/mL versus 1.12-1.78 microg/mL). According to our model, caspofungin C(24) were predicted to be significantly higher in patients with body weight <75 kg (P=0.019) and patients with albumin concentration >23.6 g/L (P=0.030). CONCLUSIONS: Our results show that body weight and albumin concentration influence caspofungin C(24) in SICU patients and should therefore be considered prognostic factors.     

Caspofungin: the first representative of a new antifungal class

Caspofungin (MK-0991; L-743,872) belongs to the echinocandin family, a new class of antifungal agents that act on the fungal cell wall by inhibiting glucan synthesis. Data in vitro, and experimental studies, have demonstrated that caspofungin has antifungal activity against yeasts of the genus Candida (including isolates resistant to azoles and amphotericin B), several species of filamentous fungi, including Aspergillus, and certain dimorphic fungi, such as Histoplasma, Blastomyces and Coccidioides. In vitro and in animals, caspofungin shows additive or synergic antifungal activity with amphotericin B and triazoles. It also possesses activity against Pneumocystis carinii. Clinical trials have shown caspofungin to be well tolerated and effective in invasive aspergillosis in patients refractory or intolerant to standard treatment (45% favourable responses), in oropharyngeal and oesophageal candidiasis (67-93% favourable responses with an efficacy similar to those of amphotericin B and fluconazole), and in invasive candidiasis with efficacy equivalent to that of amphotericin B, and better tolerability. The results of these first clinical trials were promising, and led to the approval of caspofungin for invasive aspergillosis after failure of, or intolerance to, standard therapy. Further studies are required to define the exact role of caspofungin in the antifungal armamentarium.     

Population pharmacokinetics and pharmacodynamics of caspofungin in pediatric patients

We describe the pharmacokinetics (PKs) of caspofungin, an echinocandin antifungal, administered once daily as a 1-hour intravenous infusion in children and adolescents (ages, 3 months to 17 years), based on pooled data from four prospective pediatric studies. Caspofungin dosing was body-surface-area (BSA) based (50 mg/m2 daily after 70 mg/m2 on day 1). The area under the concentration-time curve from time zero to 24 h (AUC0-24), the concentration at the end of infusion (1 h after the start of infusion; C1), and the trough concentration (24 h after the start of infusion; C24) were obtained for 32 pediatric patients with invasive candidiasis, 10 with invasive aspergillosis, and 82 in the setting of empirical therapy with fever and neutropenia. Exposures were modestly higher (93 to 134% for C1, 45 to 78% for C24, ～40% for AUC0-24) in pediatric patients than in adults receiving the standard 50-mg daily dose. The potential for covariates (age, gender, weight, race, renal status, serum albumin level, and disease state) to alter PKs was evaluated with a multiple-linear-regression model. Weight and disease state had statistically significant (P<0.05) yet small effects on caspofungin PKs in pediatric patients. Concomitant use of dexamethasone (a cytochrome p450 inducer) was associated with a statistically significant reduction (44%) in C24 in a limited number of patients (n=4). Odds ratios were estimated for the association between log-transformed PKs and treatment outcome or adverse events. No PK parameter or hybrid parameter (AUC/MIC, C1/MIC, and C24/MIC) was significantly correlated with treatment outcome or adverse events in the setting of similar response levels as adults, which suggests that the concentrations examined fall within the therapeutic window for caspofungin in pediatric patients. These results support a 50-mg/m2 daily dosing regimen (after a 70-mg/m2 loading dose) in children ages 3 months to 17 years.     

Adverse events to antiretrovirals in the Swiss HIV Cohort Study: effect on mortality and treatment modification

BACKGROUND: Antiretroviral therapy (ART) decreases morbidity and mortality in HIV-infected patients but is associated with considerable adverse events (AEs). METHODS: We examined the effect of AEs to ART on mortality, treatment modifications and drop-out in the Swiss HIV Cohort Study. A cross-sectional evaluation of prevalence of 13 clinical and 11 laboratory parameters was performed in 1999 in 1,078 patients on ART. AEs were defined as abnormalities probably or certainly related to ART. A score including the number and severity of AEs was defined. The subsequent progression to death, drop-out and treatment modification due to intolerance were evaluated according to the baseline AE score and characteristics of individual AEs. RESULTS: Of the 1,078 patients, laboratory AEs were reported in 23% and clinical AEs in 45%. During a median follow up of 5.9 years, laboratory AEs were associated with higher mortality with an adjusted hazard ratio (HR) of 1.3 (95% confidence interval [CI] 1.2-1.5; P < 0.001) per score point. For clinical AEs no significant association with increased mortality was found. In contrast, an increasing score for clinical AEs (HR 1.11,95% CI 1.04-1.18; P = 0.002), but not for laboratory AEs (HR 1.07, 95% CI 0.97-1.17; P = 0.17), was associated with antiretroviral treatment modification. AEs were not associated with a higher drop-out rate. CONCLUSIONS: The burden of laboratory AEs to antiretroviral drugs is associated with a higher mortality. Physicians seem to change treatments to relieve clinical symptoms, while accepting laboratory AEs. Minimizing laboratory drug toxicity seems warranted and its influence on survival should be further evaluated.     

Influence of human sera on the in vitro activity of the echinocandin caspofungin (MK-0991) against Aspergillus fumigatus

There have been several reports that the activity of echinocandin antifungal agents is not affected or decreased in the presence of human sera. It is known that these drugs are bound >80% in animal and human sera. The activity of the echinocandin caspofungin (MK-0991), a 1,3-beta-D-glucan synthase inhibitor, against Aspergillus fumigatus with and without human sera was studied. Conidia of A. fumigatus in microtest plate wells formed germlings after overnight culture in RPMI 1640. Caspofungin was then added with or without serum, and the germlings were incubated at 37 degrees C for 24 h. Human serum (5%) in RPMI 1640 alone did not significantly inhibit the growth of A. fumigatus in vitro. Caspofungin in RPMI 1640 exhibited dose-dependent inhibition, with concentrations of 0.1 and 0.05 microg/ml inhibiting 24.9% +/- 10.4% and 11.7% +/- 3.6%, respectively (n = 10; P < 0.01). The addition of 5% human serum to caspofungin at 0.1 or 0.05 microg/ml increased the inhibition to 78.6% +/- 5.8% or 58.3% +/- 19.2%, respectively (n = 10; P < 0.01 versus controls and versus the drug without serum). Lower concentrations of serum also potentiated drug activity. The effect of human sera was further seen when using caspofungin that had lost activity (e.g., by storage) against A. fumigatus at 0.1 microg/ml. Inactive caspofungin alone demonstrated no significant inhibition of hyphal growth, whereas the addition of 5% human serum to the inactive drug showed 83% +/- 16.5% inhibition (n = 5; P < 0. 01). The restoration of activity of caspofungin was seen at concentrations as low as 0.05% human serum. In contrast to prior reports, this study suggests that human serum acts synergistically with caspofungin to enhance its inhibitory activity in vitro against A. fumigatus.     

Efficacy of the echinocandin caspofungin against disseminated aspergillosis and candidiasis in cyclophosphamide-induced immunosuppressed mice

The in vivo efficacy of the echinocandin antifungal caspofungin acetate (caspofungin; MK-0991) was evaluated in models of disseminated aspergillosis and candidiasis in mice with cyclophosphamide (CY)-induced immunosuppression. Caspofungin is a 1, 3-beta-D-glucan synthesis inhibitor efficacious against a number of clinically relevant fungi including Aspergillus and Candida species. Models of CY-induced transient or chronic leukopenia were used with once daily administration of therapy initiated 24 h after microbial challenge. Caspofungin was effective in treating disseminated aspergillosis in mice that were transiently leukopenic (significant prolongation of survival at doses of > or =0.125 mg/kg of body weight and a 50% protective dose [PD(50)] of 0.245 mg/kg/day at 28 days after challenge) or chronically leukopenic (50 to 100% survival at doses of > or =0.5 mg/kg and PD(50)s ranging from 0.173 to 0.400 mg/kg/day). Caspofungin was effective in the treatment and sterilization of Candida infections in mice with transient leukopenia with a 99% effective dose based on reduction in log(10) CFU of Candida albicans/gram of kidneys of 0.119 mg/kg and 80 to 100% of the caspofungin-treated mice having sterile kidneys at caspofungin doses from 0.25 to 2.0 mg/kg. In Candida-infected mice with chronic leukopenia, caspofungin was effective at all dose levels tested (0.25 to 1.0 mg/kg), with the log(10) CFU of C. albicans/gram of kidneys of caspofungin-treated mice being significantly lower (>99% reduction) than that of sham-treated mice from day 4 to day 28 after challenge. Also, 70 to 100% of the caspofungin-treated, chronic leukopenic mice had sterile kidneys at caspofungin doses of 0.5 to 1.0 mg/kg from day 8 to 28 after challenge. Sterilization of Candida infections by caspofungin in the absence of host leukocytes provides compelling in vivo evidence for fungicidal activity against C. albicans. Further human clinical trials with caspofungin against serious fungal infections are in progress.     

Caspofungin: antifungal activity in vitro, pharmacokinetics, and effects on fungal load and animal survival in neutropenic rats with invasive pulmonary aspergillosis

OBJECTIVES: Evaluation of the potential of caspofungin, in relation to pharmacokinetics, in order to optimize its use in the treatment of filamentous fungal infections. METHODS: The in vitro antifungal activity, pharmacokinetics and therapeutic efficacy of caspofungin versus amphotericin B was investigated in vitro as well as in a model of aerogenic Aspergillus fumigatus infection in neutropenic rats, using rat survival and decrease in fungal burden as parameters for therapeutic efficacy. RESULTS: In contrast to amphotericin B, caspofungin shows a concentration-dependent gradual decrease in fungal growth in vitro, which makes it difficult to perform visual readings of antifungal activity (CLSI guidelines). The quantitative XTT [2,3-bis(2-methoxy-4-nitro-5-[(sulphenylamino) carbonyl]-2H-tetrazolium-hydroxide] assay measuring a decrease in fungal metabolic activity seems more appropriate for caspofungin susceptibility testing. Using this assay, in vitro caspofungin was 4-fold less active than amphotericin B. In the infection model, therapy was started 16 h after fungal inoculation, and continued once daily for 10 days. Caspofungin was administered intraperitoneally at 1, 2, 3 or 4 mg/kg/day (CAS 1, 2, 3 or 4), amphotericin B at 1 mg/kg/day (AMB 1). Treatment with CAS 1 or AMB 1 provided modest prolongation of animal survival. The combination of caspofungin and amphotericin B did not show additive effects. Increasing the dosage of caspofungin to 2, 3 or 4 mg/kg/day resulted in a dose-dependent significant increase in efficacy. There was 100% survival among rats in the CAS 4 group, which was correlated with a significant decrease in fungal burden, based on the concentration of A. fumigatus galactomannan in serum and lung tissue and quantification of A. fumigatus DNA in lung tissue. Pharmacokinetic analysis suggested that the CAS 4 dose in rats produced drug exposure comparable to the human situation, visualized by similar 24 h AUC and trough concentrations. CONCLUSIONS: The therapeutic efficacy of caspofungin is superior to amphotericin B, which seemed to be discrepant with their in vitro antifungal activity.     

Pharmacokinetics of Caspofungin in Critically Ill Patients on Continuous Renal Replacement Therapy

Caspofungin pharmacokinetics was assessed in 27 critically ill patients, including 7 on continuous venovenous hemofiltration (CVVH), 8 on continuous venovenous hemodialysis (CVVHD), and 13 not requiring continuous renal replacement therapy (CRRT). Caspofungin exposure during CRRT was very similar to that of the control group and comparable to that in healthy volunteers. Caspofungin clearance by CRRT was very low. Therefore, the standard dosage of caspofungin is probably adequate for critically ill patients undergoing CVVH or CVVHD.     

Phase II dose escalation study of caspofungin for invasive Aspergillosis

Our objective was to evaluate the maximum tolerated dose of caspofungin for invasive aspergillosis (IA). The safety and pharmacokinetics of escalating dosages of caspofungin were investigated in IA. Eight patients each received caspofungin 70, 100, 150, or 200 mg once a day (QD). Dose-limiting toxicity (DLT) was defined as the same non-hematological treatment-related adverse event of grade ≥ 4 in 2 of 8 patients or ≥ 3 in 4 of 8 patients in a cohort. A total of 46 patients (median age, 61 years; 21 female; 89% with hematological malignancies) received caspofungin (9, 8, 9, and 20 patients in the 70-, 100-, 150-, and 200-mg cohorts) for a median of 24.5 days. Plasma pharmacokinetics were linear across the investigated dosages and followed a two-compartment model, with weight as the covariate on clearance and sex as the covariate on central volume of distribution. Simulated peak plasma concentrations at steady state ranged from 14.2 to 40.6 mg/liter (28%), trough concentrations from 4.1 to 11.8 mg/liter (58%), and area under the concentration-time curve from 175 to 500 mg/liter/h (32%) (geometric mean, geometric coefficient of variation). Treatment was well tolerated without dose-limiting toxicity. The rate of complete or partial responses was 54.3%, and the overall mortality at 12-week follow-up was 28.3%. In first-line treatment of invasive aspergillosis, daily doses of up to 200 mg caspofungin were well tolerated and the maximum tolerated dose was not reached. Pharmacokinetics was linear. Response rates were similar to those previously reported for voriconazole and liposomal amphotericin.     

Five-minute exposure to caspofungin results in prolonged postantifungal effects and eliminates the paradoxical growth of Candida albicans

We studied the impact of brief caspofungin exposures on postantifungal effects (PAFEs) and paradoxical effects for five Candida albicans isolates. In time-kill studies, caspofungin at 4× and 16× the MIC resulted in significant killing of all isolates. Caspofungin at 8 μg/ml resulted in lower levels of killing, and paradoxical effects were evident with 4 isolates. Caspofungin exposures of 5 to 60 min caused prolonged, concentration-dependent killing that approached or exceeded the results seen with time-kill experiments and eliminated paradoxical growth.     

Overexpression of Sbe2p,a Golgi protein,results in resistance to caspofungin in Saccharomyces cerevisiae

Caspofungin inhibits the synthesis of 1, 3-beta-D-glucan, an essential cell wall target in fungi. Genetic studies in the model yeast Saccharomyces cerevisiae have shown that mutations in FKS1 and FKS2 genes result in caspofungin resistance. However, direct demonstration of the role of gene overexpression in caspofungin resistance has been lacking. We transformed wild-type S. cerevisiae with an S. cerevisiae URA3-based GAL1 cDNA library and selected transformants in glucose synthetic complete plates lacking uracil (glucose SC minus uracil plates). We then moved the transformants to galactose SC minus uracil plates containing caspofungin (1 microg/ml) and looked for caspofungin-resistant colonies. We retested the candidates (true positives were sensitive on glucose caspofungin and resistant on galactose caspofungin media, respectively). We identified 16 caspofungin-resistant candidates. Restriction analysis and hybridization confirmed that 15 of the 16 clones were identical. We sequenced one of the cDNA clones and found that it contained the cDNA for SBE2. SBE2 has been described in S. cerevisiae to encode a Golgi protein involved in the transport of cell wall components (B. Santos and M. Snyder, Mol. Biol. Cell, 11:435-452, 2000). The SBE2 cDNA plasmid conferred again galactose-dependent caspofungin resistance when transformed back into the wild-type S. cerevisiae. Finally, the SBE2 deletion mutant was hypersensitive to caspofungin. In conclusion, overexpression of Sbe2p under the regulated control of the GAL1 promoter results in caspofungin resistance in S. cerevisiae. This transport pathway may provide insight into the tolerance or lack of sensitivity to caspofungin of some pathogenic fungi.