Efficacy and safety of caspofungin therapy in children with invasive fungal infections

Caspofungin as antifungal prophylaxis in pediatric patients undergoing allogeneic hematopoietic stem cell transplantation: a retrospective analysis

Background

Pediatric patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT) often receive intravenous liposomal amphotericin B (L-AmB) as antifungal prophylaxis. There are no guidelines for antifungal prophylaxis in children in this situation. Caspofungin (CAS), a broad-spectrum echinocandin, could be an effective alternative with lower nephrotoxicity than L-AmB.

Methods

We retrospectively analyzed the safety, feasibility, and efficacy of CAS in our center, and compared the results with L-AmB as antifungal monoprophylaxis in pediatric patients undergoing HSCT. 60 pediatric patients received L-AmB (1 or 3 mg/kg bw/day) and another 60 patients received CAS (50 mg/m²/day) as antifungal monoprophylaxis starting on day one after HSCT. The median ages of patients receiving L-AmB and CAS were 7.5 years and 9.5 years, respectively.

Results

No proven breakthrough fungal infection occurred in either group during the median treatment period of 23 days in the L-AmB group and 24 days in the CAS group. One patient receiving CAS developed probable invasive aspergillosis. During L-AmB treatment, potassium levels significantly decreased below normal values. Patients treated with L-AmB had more drug-related side effects and an increased need for oral supplementation with potassium, sodium bicarbonate and calcium upon discharge as compared with the CAS group. CAS was well-tolerated and safe in this cohort of immunocompromised pediatric patients, who underwent high-dose chemotherapy and HSCT.

Conclusion

Prophylactic CAS and L-AmB showed similar efficacy in this biggest cohort of pediatric patients after allogeneic HSCT reported, so far. A prospective randomized trial in children is warranted to allow for standardized guidelines.

The use of antifungal therapy in neonatal intensive care

Invasive fungal infections remain a significant cause of infection-related mortality and morbidity in preterm infants. Central nervous system involvement is the hallmark of neonatal candidiasis, differentiating the disease's impact on young infants from that among all other patient populations. Over the past decade, the number of antifungal agents in development has grown, but most are not labeled for use in newborns. We summarize the findings of several antifungal studies that have been completed to date, emphasizing those including infant populations. We conclude that more studies are required for antifungals to be used safely and effectively in infants.

Epidemiology, risk factors and therapy of candidemia in pediatric hematological patients

Invasive fungal infections (IFI) are an important cause of morbidity, increased hospitalization and healthcare costs in critically ill or immunocompromised children. The mortality is comprised between 5 and 20%. In the last 2 decades, the epidemiology of candidemia has changed with an increase of episodes caused by non-Candida albicans species. Central venous catheter, diagnosis of malignancy, and receipt of either vancomycin or antimicrobials with activity against anaerobic organisms for >3 days have been associated with the development of candidemia in the pediatric intensive care unit (PICU). Additional risk factors found in hematological patients were the diagnosis of aplastic anemia, performing an unrelated bone marrow or cord blood transplant, the occurrence of a graft versus host disease and the use of steroids. Early antifungal treatment is recommended to reduce mortality. In neutropenic patients, liposomal amphotericin B, an echinocandin (caspofungin, micafungin), and voriconazole are considered the best option especially for C. glabrata and C. krusei. Fluconazole remains a valid option for infection by Candida albicans in patients not exposed to fluconazole prophylaxis. Amphotericn B deoxy-cholate is generally not recommended because of its nephrotoxicity.

Caspofungin therapy in immunocompromised children and neonates

The prevalence of invasive fungal infections is increasing and the infections are becoming a major problem in immunocompromised children and neonates. Fortunately, there has been a recent surge in the development of new antifungal agents. Caspofungin, the first licensed echinocandin, is a novel class of antifungal and is approved for use in children 3 months of age or older for the treatment of invasive candidiasis, salvage therapy for invasive aspergillosis and as empirical therapy for febrile neutropenia. This article reviews the published data on the use of caspofungin in immunocompromised children and neonates with invasive fungal infections.

[Echinocandins in children]

Echinocandins are a new class of antifungal agents with a specific mechanism of action. These drugs inhibit the enzyme 1,3β-D-glucan synthetase which is responsible for the formation of 1,3β-D-glucan, an essential fungal cell wall component. They have a good activity against Candida species and Aspergillus. Three agents are available at the present time or under development : caspofungin, micafungin and anidulafungin. These drugs require intravenous administration. Efficacy, safety, rare drugs interactions and specificity of action are advantages for therapy of invasive fungal infections. In France, micafungin and caspofungin are approved for a pediatric use.

[Guidelines for the treatment of Invasive Candidiasis and other yeasts. Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC). 2010 Update]

These guidelines are an update of the recommendations of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) that were issued in 2004 (Enferm Infecc Microbiol Clin. 2004, 22:32-9) on the treatment of Invasive Candidiasis and infections produced by other yeasts. This 2010 update includes a comprehensive review of the new drugs that have appeared in recent years, as well as the levels of evidence for recommending them. These guidelines have been developed following the rules of the SEIMC by a working group composed of specialists in infectious diseases, clinical microbiology, critical care medicine, paediatrics and oncology-haematology. It provides a series of general recommendations regarding the management of invasive candidiasis and other yeast infections, as well as specific guidelines for prophylaxis and treatment, which have been divided into four sections: oncology-haematology, solid organ transplantation recipients, critical patients, and paediatric patients.

Invasive respiratory aspergillosis is a treatable disease with early diagnosis and aggressive therapy

This study aimed to document outcome of invasive respiratory aspergillosis (IRA) in pediatric malignancy patients. Patients with febrile neutropenia episodes followed between January 2003 and May 2007 were enrolled. Antifungal therapy was added to those who were still febrile on the 5th day of febrile neutropenia treatment. Patients were screened with computerized tomographies. IRA was identified in 22 of 98 patients. There were 13 males and the mean age was 97 months. Proven infection was established in 3, probable in 7, and possible in 12 patients. Liposomal amphotericin B was administered to all patients and was successful in 10 patients. Modifications with caspofungin or voriconazole were done in liposomal amphotericin B failures. The median duration of antifungal therapy was 5.5 months. The median follow-up time was 29 months. There was no evidence of IRA in 12 patients after completion of cancer chemotherapy. Six patients died due to underlying disease, whereas IRA was either in remission or stable disease. Four patients were lost due to IRA. The remission rate for IRA was 82%. Survival at 37 months was 55% (95% confidence interval 25-47 months). The amount of time that absolute neutrophil count after initiation of treatment for IRA remained at zero was found to be an independent prognostic factor on survival (P = .01). These results suggest that early diagnosis and aggressive treatment may increase the successful outcome of IRA.

Pediatric antifungal agents

PURPOSE OF REVIEW

In immunocompromised hosts, invasive fungal infections are common and fatal. In the past decade, the antifungal armamentarium against invasive mycoses has expanded greatly. The purpose of the present report is to review the most recent literature addressing the use of antifungal agents in children.

RECENT FINDINGS

Most studies evaluating the safety and efficacy of antifungal agents are limited to adults. However, important progress has been made in describing the pharmacokinetics and safety of newer antifungal agents in children, including the echinocandins.

SUMMARY

Dosage guidelines for newer antifungal agents are currently based on adult and limited pediatric data. Because important developmental pharmacology changes occur throughout childhood impacting the pharmacokinetics of these agents, antifungal studies specifically designed for children are necessary.

A Clinical Review of Echinocandins in Pediatric Patients

OBJECTIVE

To identify and evaluate available data on pediatric echinocandin use.

DATA SOURCES

A PubMed search, limited to English-language articles, was conducted (1990-August 2009) using the search terms echinocandin, pediatric, child, pharmacokinetics, caspofungin, micafungin, and anidulafungin. Additional articles were retrieved from citations of selected references.

STUDY SELECTION AND DATA EXTRACTION

Relevant information on the pharmacology, pharmacokinetics, efficacy, and safety of echinocandins in children was selected. Clinical trials, retrospective reviews, and case series were identified and evaluated. Data from these sources were included in this review.

DATA SYNTHESIS

Caspofungin is the only echinocandin approved by the Food and Drug Administration for use in children. Pediatric pharmacokinetics has been evaluated with all 3 echinocandins but is limited with anidulafungin. Micafungin is the most well-studied agent in prospective clinical trials for antifungal prophylaxis in stem cell transplantation and treatment of invasive fungal infections. Caspofungin has been studied prospectively for febrile neutropenia and treatment of invasive fungal infections, but most published data are from retrospective reviews or case reports. One case report of anidulafungin for neonatal candidiasis has been published. The role of echinocandins in the management of invasive pediatric fungal infections has expanded. Micafungin and caspofungin are recommended as primary or alternative treatment of candidemia and esophageal or invasive candidiasis, and as salvage therapy for invasive aspergillosis. Micafungin is recommended for neutropenic prophylaxis in stem cell transplantation, while caspofungin may be used in febrile neutropenia as an alternative to azoles. Dosing has been well established for caspofungin only in children 3 months of age and above. Anidulafungin should be avoided in children until more pharmacokinetic and clinical data become available.

CONCLUSIONS

Further comparative trials are needed to more clearly define the role of echinocandins, either as monotherapy or in combination for difficult-to-treat infections, in the pediatric population.

Invasive candidiasis in pediatric intensive care units

Candidemia and disseminated candidiasis are major causes of morbidity and mortality in hospitalized patients especially in the intensive care units (ICU). The incidence of invasive candidasis is on a steady rise because of increasing use of multiple antibiotics and invasive procedures carried out in the ICUs. Worldwide there is a shifting trend from C. albicans towards non albicans species, with an associated increase in mortality and antifungal resistance. In the ICU a predisposed host in one who is on broad spectrum antibiotics, parenteral nutrition, and central venous catheters. There are no pathognomonic signs or symptoms. The clinical clues are: unexplained fever or signs of severe sepsis or septic shock while on antibiotics, multiple, non-tender, nodular erythematous cutaneous lesions. The spectrum of infection with candida species range from superficial candidiasis of the skin and mucosa to more serious life threatening infections. Treatment of candidiasis involves removal of the most likely source of infection and drug therapy to speed up the clearance of infection. Amphotericin B remains the initial drug of first choice in hemodynamically unstable critically ill children in the wake of increasing resistance to azoles. Evaluation of newer antifungal agents and precise role of prophylactic therapy in ICU patients is needed.

Invasive mold infections in iatrogenically immunocompromised children: an eight-yr review

IMI are emerging as an important cause of mortality and morbidity among the growing number of immunocompromised children. A retrospective chart review was performed in all patients with a proven diagnosis of IMI over an eight-yr period (1997-2004) at The Hospital for Sick Children, Toronto, Canada to document the incidence, clinical spectrum, microbiology, treatment, and outcome of pediatric IMI. Twenty-eight patients developed IMI over the study period (10 cancer, 12 HCT, and six SOT patients). IMI occurred in 0.51%, 2.2% and 3.2% after a median time of 118, 60 and 71 days, among cancer, HCT and SOT recipients, respectively. Aspergillus spp. infection was diagnosed most commonly (23 patients) and the most common site of infection was the lung (21 patients). Patients at increased risk included those with acute myelogenous leukemia, allogeneic unrelated HCT recipients, graft-versus-host disease, and lung transplant recipients. The mortality after one yr was 60% among cancer patients, 58% among HCT patients, and 16% among SOT patients.

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.

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.

Galactomannan antigenemia in pediatric oncology patients with invasive aspergillosis

BACKGROUND

Diagnosing invasive aspergillosis is difficult but might be improved by detection of circulating galactomannan. Although galactomannan antigenemia has been well studied in the detection of invasive aspergillosis in adult patients, little is known about the expression of circulating galactomannan in immunocompromised children with invasive aspergillosis.

METHODS

We studied the expression of galactomannan antigen by enzyme immunoassay (EIA) in 990 serum samples from 56 pediatric oncology patients (ages 3 months to 18 years) of whom 17 had proven or probable invasive aspergillosis defined by the European Organization for Research and Treatment of Cancer-Mycoses Study Group criteria. Any sample with a galactomannan EIA Galactomannan index value of > or = 0.5 was considered positive.

RESULTS

At least 1 serum sample was positive for 11 of 17 pediatric oncology patients (65.7% sensitivity, 95% confidence interval: 38.3-85.7) with invasive aspergillosis. Galactomannan EIA was positive in 99 of 304 samples from patients with proven or probable invasive aspergillosis, and 7 of 686 (1.0%) samples from 39 control subjects resulted in a positive galactomannan EIA result. At least 1 sample tested positive in 5 of the 39 controls (12.8%, 95% confidence interval: 4.3-27.4). No significant association between accuracy and patient age was observed. Among the 7 evaluable galactomannan-positive patients with IA, the galactomannan EIA produced a positive result before clinical or radiographic evidence of infection in 6 cases, with a lead-time to diagnosis ranging from 1 day to 34 days (median: 10 days). In the remaining case, a positive galactomannan was observed on the same day as diagnosis by non-EIA methods.

CONCLUSIONS

The presence of circulating galactomannan is predictive of invasive aspergillosis in most pediatric oncology patients. Galactomannan antigenemia may precede clinical, microbiologic, or radiographic evidence of invasive aspergillosis.

Early clinical experience with anidulafungin at a large tertiary care medical center

STUDY OBJECTIVE

To evaluate early clinical experience with anidulafungin.

DESIGN

Retrospective cohort study.

SETTING

Large, university-affiliated, tertiary care medical center.

PATIENTS

All patients receiving anidulafungin between July 15, 2006, and January 15, 2007.

MEASUREMENTS AND MAIN RESULTS

Thirty-five patients received at least one dose of anidulafungin. Safety and tolerability were evaluated in all patients; efficacy outcomes were assessed in 13 patients who had a documented fungal infection and received anidulafungin for a minimum of 5 days. Common conditions at baseline were hepatic dysfunction (25 patients [71%]), severe sepsis (17 patients [49%]), and solid organ or hematopoietic stem cell transplantation (10 patients [29%]). Eight patients (23%) were receiving drugs with the potential to interact with echinocandins other than anidulafungin. Seventeen (49%) of the 35 patients received anidulafungin as empiric antifungal therapy. Anidulafungin was used to treat invasive candidiasis in seven patients (20%) and candidemia in 10 patients (29%); Candida albicans or Candida glabrata was isolated most frequently in these two infections combined (7 isolates each [41%]/17 infections). A favorable efficacy outcome was noted in 10 (77%) of 13 evaluable patients. One patient developed breakthrough Candida parapsilosis fungemia while receiving anidulafungin. Overall, anidulafungin was well tolerated, with only one patient having an infusion- related reaction. Anidulafungin was also well tolerated among patients receiving concomitant metronidazole.

CONCLUSION

Anidulafungin was well tolerated and produced favorable outcomes in the majority of the patients evaluated. The availability of anidulafungin makes it a feasible option for antifungal therapy, particularly in patients who have hepatic dysfunction and in those who are receiving drugs than can interact with other echinocandins.