Treatment of invasive pulmonary aspergillosis in severely neutropenic children with malignant disorders using liposomal amphotericin B (AmBisome), granulocyte colony-stimulating factor, and surgery: report of five cases

Safety, Tolerability, and Pharmacokinetics of Liposomal Amphotericin B in Immunocompromised Pediatric Patients

The safety, tolerability, and pharmacokinetics of the liposomal formulation of amphotericin B (L-AMB) were evaluated in 40 immunocompromised children and adolescents. The protocol was an open-label, sequential-dose-escalation, multidose pharmacokinetic study with 10 to 13 patients in each of the four dosage cohorts. Each cohort received daily dosages of 2.5, 5.0, 7.5, or 10 mg of amphotericin B in the form of L-AMB per kg of body weight. Neutropenic patients between the ages of 1 and 17 years were enrolled to receive empirical antifungal therapy or treatment of documented invasive fungal infections. The pharmacokinetic parameters of L-AMB were measured as those of amphotericin B by high-performance liquid chromatography and calculated by noncompartmental methods. There were nine adverse-event-related discontinuations, four of which were related to infusions. Infusion-related side effects occurred for 63 (11%) of 565 infusions, with 5 patients experiencing acute infusion-related reactions (7.5- and 10-mg/kg dosage levels). Serum creatinine levels increased from 0.45 ± 0.04 mg/dl to 0.63 ± 0.06 mg/dl in the overall population (P = 0.003), with significant increases in dosage cohorts receiving 5.0 and 10 mg/kg/day. At the higher dosage level of 10 mg/kg, there was a trend toward greater hypokalemia and vomiting. The area under the concentration-time curve from 0 to 24 h (AUC_0-24) values for L-AMB on day 1 increased from 54.7 ± 32.9 to 430 ± 566 μg · h/ml in patients receiving 2.5 and 10.0 mg/kg/day, respectively. These findings demonstrate that L-AMB can be administered to pediatric patients at dosages similar to those for adults and that azotemia may develop, especially in those receiving ≥5.0 mg/kg/day.

The role of surgery in the treatment of invasive fungal infection in paediatric haematology patients: a retrospective single-centre survey

Surgery may improve the control of fungal disease and patient survival. The aim of this study was to report a single-centre experience in using surgery for the treatment of paediatric invasive fungal infection (IFI). From 2001 to 2009, 18 paediatric onco-haematology patients underwent 24 surgical procedures as treatment of IFI. At surgery, severe thrombocytopenia and neutropenia were present in four and one episodes respectively. Complications were one pleural effusion, one pleural effusion and surgical wound infection, one pneumothorax with wound dehiscence and one wound dehiscence. None of them required repeat surgery. The median duration of hospitalisation for four complicated procedures was 11 days, range 3-16, and 7 days, range 2-13, for the 20 uncomplicated procedures. No surgery-related deaths occurred. Fourteen patients resumed chemotherapy after a median of 26 days, range 9-77, whereas nine patients underwent hematopoietic stem cell transplantation after a median of 42 days, range 27-110. At 3 months from IFI, 17 patients were alive (94%) and one patient (6%) died from mycosis; the 3-month overall survival (OS) being 94.4%, CI 66.6-99.2. After a median follow-up of 7.1 years (CI 2.8-7.5), the OS was 54.5%, CI 29.2-74.2. Surgery is a feasible and valuable option in paediatric patients because it is associated with a low incidence of complications and an acceptable delay in resuming the chemotherapeutic plan.

Immunotherapies in infectious diseases

The development of an infection involves interplay between the host's immune system and the virulence of the infecting microorganism. The traditional treatment of an infection involves antimicrobial chemotherapy to kill the organism. The use of immunotherapies in infections includes treatment options that modulate the immune response and can lead to control of infections. These therapies are expected to become more important therapeutic options with the increase in infections due to multidrug-resistant organisms and the increasing number of immunocompromised patients.

[Place of surgery in pulmonary aspergillosis and other pulmonary mycotic infections]

Surgery is part of the therapeutic strategy of aspergillosis and mucormycosis. The aspergilloma is defined as a rounded mass, developing in a cavity by the proliferation of spores of Aspergillus. The most common complication was haemoptysis reported in 50-95% of cases. The pleuropulmonary lesions predisposing are: tuberculosis, residual pleural space, emphysema and lung destroyed by fibrosis or radiotherapy or bronchiectasis. The indications for surgery depend on symptoms, respiratory function, the parenchyma and the type of aspergilloma (simple or complex). In a patient with an intrapulmonary aspergilloma, lung resection preceded by embolization is recommended based on respiratory function. For intrapleural aspergilloma, thoracoplasty is recommended according to the patient's general condition. The invasive pulmonary aspergillosis (IPA) is characterized by an invasion of lung tissue and blood vessels by hyphae in immunocompromised patients. The death rate of patients who have an API after treatment for leukemia or lymphoma was 30 to 40%, after bone marrow transplantation 60%, after solid organ transplantation from 50 to 60% and after any other cause of immunocompromising from 70 to 85%. The main cause of these deaths is massive hemoptysis. Surgery (lobectomy) is indicated for the prevention of hemoptysis when the mass is in contact with the pulmonary artery or one of its branches, and if it increases in size with the disappearance of border security between the mass and the vessel wall. The patient will be operated in an emergency before the white blood cells do not exceed the threshold of 1000 cells/μl. A persistent residual mass after antifungal treatment may justify a lung resection (lobectomy or wedge) before a new aggressive therapy. Mucormycosis affects patients following immunocompromising states--haematologic malignancy, diabetes mellitus, transplantation, burns and malnutrition. The treatment of pulmonary mucormycosis combines surgical and medical approach.

Results of a multicenter retrospective study of a combined medical and surgical approach to pulmonary aspergillosis in pediatric neutropenic patients

BACKGROUND

Invasive aspergillosis (IA) is a serious problem in patients suffering from hematological malignancies. Surgical resection has been reported to improve disease control and patient survival. There are few reports describing the role of surgery in children with pulmonary IA.

PROCEDURE

From October 1998 to September 2005, 21 patients fulfilled the inclusion criteria. Demographic and clinical data, as well as type and duration of antifungal therapy; surgery and related complications; time elapsing from surgery to resumption of chemotherapy were collected retrospectively through a specially designed form filled in by each investigator.

RESULTS

Eleven males and 10 females, aged between 2 and 17 years underwent one or more surgical lung resections for diagnostic and therapeutic purposes. Surgical complications were reported in three patients. Two patients, who underwent a wedge resection and a lobectomy, respectively, had no fungal lesions detected at surgery. Seventeen of 20 patients with malignancy resumed chemotherapy after a median of 19 days from surgery, range 7-81, and 11 of them underwent hematopoietic stem cell transplantation after a median time of 60 days from surgery, range 19-110. After a median follow-up of 1.7 years, 12 patients are alive while 9 patients have died from progression of their underlying disease.

CONCLUSIONS

This study suggests that the combination of medical antifungal therapy and early surgical excision is a feasible and an effective strategy in pediatric patients with IA. In order to avoid unnecessary surgical procedures, we advise checking the response to antifungal therapy by chest-computed tomography immediately before the date of surgery.

Interferon-gamma and colony-stimulating factors as adjuvant therapy for refractory fungal infections in children

A human immunodeficiency virus-infected boy with Scedosporium apiospermum otomastoiditis and a girl with diabetes mellitus and Mucor sinusitis and orbital cellulitis had life-threatening disease progression despite antifungal treatment. Interferon-gamma and granulocyte-macrophage or granulocyte colony-stimulating factor were added, with good functional outcome in both children. Adjunctive therapy with interferon-gamma, granulocyte-macrophage colony-stimulating factor and granulocyte colony-stimulating factor can be considered for refractory invasive fungal infections.

Combinatorial immunotherapies for infectious diseases

Combating pathogenic organisms by combinatorial approaches involving appropriate immune response molecules and antimicrobial drugs represents a progessively more apparent and successful therapeutic paradigm for the treatment of acute and chronic persistent infectious diseases. This review explores areas of current innovation and provides an update of the present state of knowledge concerning combination of chemotherapy with several immune-based interventions in infections. In the future, a better understanding of microbial immune modulation and evasion may continue to open new avenues of inquiry and carefully targeted application of adjunctive immunotherapies.

Immunomodulation of invasive fungal infections

Genetic and acquired (disease- or therapy- related) host immune factors increase the risk for IFIs. In addition to antifungal drug therapy, modulation of host defenses by the use of HGFs and IFN-gamma has been supported by extensive in vitro and in vivo preclinical data. Clinical studies on the prevention or the adjunctive therapy of IFIs in combination with antifungal agents are limited, however, and do not allow specific recommendations for their cost-effective use in most of the immunodeficient settings. There is an urgent need to push forward with well-structured, randomized clinical trials to determine optimal dose, duration, and timing for different combinations of immunotherapy and antifungal agents in high-risk patients.

Antifungal drug resistance to azoles and polyenes

There is an increased awareness of the morbidity and mortality associated with fungal infections caused by resistant fungi in various groups of patients. Epidemiological studies have identified risk factors associated with antifungal drug resistance. Selection pressure due to the continuous exposure to azoles seems to have an essential role in developing resistance to fluconazole in Candida species. Haematological malignancies, especially acute leukaemia with severe and prolonged neutropenia, seem to be the main risk factors for acquiring deep-seated mycosis caused by resistant filamentous fungi, such us Fusarium species, Scedosporium prolificans, and Aspergillus terreus. The still unacceptably high mortality rate associated with some resistant mycosis indicates that alternatives to existing therapeutic options are needed. Potential measures to overcome antifungal resistance ranges from the development of new drugs with better antifungal activity to improving current therapeutic strategies with the present antifungal agents. Among the new antifungal drugs, inhibitors of beta glucan synthesis and second-generation azole and triazole derivatives have characteristics that render them potentially suitable agents against some resistant fungi. Other strategies including the use of high doses of lipid formulations of amphotericin B, combination therapy, and adjunctive immune therapy with cytokines are under investigation. In addition, antifungal control programmes to prevent extensive and inappropriate use of antifungals may be needed.

Linking hematopoiesis to endochondral skeletogenesis through analysis of mice transgenic for collagen X

Each skeletal element where marrow develops is first defined by a hypertrophic cartilage blueprint. Through programmed tissue substitution, the cartilaginous skeletal model is replaced by trabecular bone and marrow, with accompanying longitudinal tissue growth. During this process of endochondral ossification, hypertrophic cartilage expresses a unique matrix molecule, collagen X. Previously we reported that transgenic mice with dominant interference collagen X mutations develop variable skeleto-hematopoietic abnormalities, manifested as growth plate compressions, diminished trabecular bone, and reduced lymphatic organs (Nature 1993, 365:56). Here, histology and flow cytometry reveal marrow hypoplasia and impaired hematopoiesis in all collagen X transgenic mice. A subset of mice with perinatal lethality manifested the most severe skeletal defects and a reduction of marrow hematopoiesis, highlighted by a lymphocyte decrease. Thymic reduction is accompanied by a paucity of cortical immature T cells, consistent with the marrow's inability to replenish maturing cortical lymphocytes. Diminished spleens exhibit indistinct lymphatic nodules and red pulp depletion; the latter correlates with erythrocyte-filled vascular sinusoids in marrows. All mice display reduced B cells in marrows and spleens, and elevated splenic T cells. These hematopoietic defects underscore an unforeseen link between hypertrophic cartilage, endochondral ossification, and establishment of the marrow microenvironment required for blood cell differentiation.

Granulocyte colony-stimulating factor and other cytokines in antifungal therapy

Invasive fungal infections (IFIs) have emerged as a serious threat in immunocompromised patients during the last two decades. Host defenses including appropriate cytokine responses and intact phagocytic function are necessary to combat IFIs. Several cytokines have been investigated and developed for preventive and therapeutic use. Among them, granulocyte colony-stimulating factor (G-CSF) has been mostly studied and used for various purposes, the most important being the faster recovery from neutropenia. Other cytokines with potential clinical significance in relation to IFI are granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon-gamma (IFN-gamma) and macrophage colony-stimulating factor. Supported by a large number of preclinical studies but limited clinical results their potential utility against IFI has been suggested. In this review, certain questions related to this issue are discussed based on data already available and an attempt to consider future research is made.

Adjunctive immune therapy for fungal infections

Fungal infections in immunocompromised patients can pose difficult problems in clinical management, because the available antifungal chemotherapy is often unable to eradicate the infection in these people. Hence, the use of immune modulating therapy to augment impaired host immune responses--and thus enhance the efficacy of antifungal drugs--is a reasonable approach to improve the prognosis of fungal infections. Advances in biotechnology have produced a variety of biological response modifiers with the potential to serve as adjunctive immune therapy for the treatment of fungal infections, including cytokines, monoclonal antibodies, and cell growth factors. In recent years, immune-modulating therapies have been studied in an effort to define their potential use for the treatment of fungal infections. Much of the available information on the use of this approach is encouraging and invites further investigation--with the caveats that the information is mostly anecdotal and that immune-modulating therapy occasionally has produced adverse effects.

Five-year-survey of invasive aspergillosis in a paediatric cancer centre. Epidemiology, management and long-term survival

The epidemiology, management, and long-term survival of invasive aspergillosis was assessed in a prospective, 5-year observational study in 346 unselected paediatric cancer patients receiving dose-intensive chemotherapy for newly diagnosed or recurrent malignancies. Invasive aspergillosis occurred exclusively in the context of haematological malignancies, where it accounted for an incidence of 6.8% (n = 13 of 189). The lung was the primary site in 12 cases, and dissemination was present in three of those. Prior to diagnosis, the overwhelming majority of patients had been profoundly neutropenic for at least 14 days (n = 11 of 13) and were receiving systemic antifungal agents (n = 10 of 13). Clinical signs and symptoms were nonspecific but always included fever. All 11 patients who were diagnosed and treated during lifetime for a minimum of 10 days responded to either medical or combined medical and surgical treatment, and seven were cured (64%). Nevertheless, the overall long-term survival was merely 31% after a median follow-up of 5.68 years after diagnosis. Apart from refractory or recurrent cancer, the main obstacles to successful outcome were failure to diagnose IA during lifetime and bleeding complications in patients with established diagnosis. The frequency of invasive aspergillosis of greater than 15% in paediatric patients with acute myeloblastic leukaemia and recurrent leukaemias warrants the systematic investigation of preventive strategies in these highly vulnerable subgroups.

Treatment of fungal infections in neutropenic children

Fungal infections have emerged as one of the most significant complications of antineoplastic therapy and marrow transplantation in children. Morbidity and mortality associated with fungal infections are high. Recent trends indicate that the incidence and spectrum of fungal infections are increasing, partly because of the increase in the number of children receiving intensive chemotherapy and marrow transplantation, but also because of the successful management of bacterial and viral infections. Though many factors may contribute to risk for developing a fungal infection, prolonged neutropenia is the most important. Until recently, options for antifungal therapy were limited. Advances include less toxic formulations of amphotericin B and an expanding armamentarium of azoles as well as new antifungal compounds. This review addresses the therapeutic options available for treatment of fungal infections in immunocompromised children.

Invasive sinus aspergillosis in apparently immunocompetent hosts

OBJECTIVES

to describe the clinical, microbiological and pathological features of invasive sinus aspergillosis affecting immunocompetent hosts, and to identify the risk factors for mortality.

METHODS

we report three apparently immunocompetent patients with invasive sinus aspergillosis, and review all cases reported in the English literature since 1987, the year in which the triazole antifungal agents were introduced.

RESULTS

twenty-nine patients (including three of our own) were identified. The presenting symptoms were non-specific and indistinguishable from viral, bacterial or allergic causes of sinusitis. The findings on computed tomography scan were also non-specific, and histopathology and culture of sinus tissue biopsy had low yield. These factors, along with the mistaken impression that Aspergillus can only affect immunocompromised hosts, frequently delayed the diagnosis. Fifty-nine percent of patients either failed therapy or died. The following factors were associated with a poor prognosis: delayed diagnosis, intracranial extension of infection, and histopathology demonstrating hyphal invasion of blood vessel or tissue. Complete surgical extirpation was the key element of successful therapy; antifungal agents played an adjunctive role.

CONCLUSIONS

invasive sinus aspergillosis carries high morbidity and mortality, even in immunocompetent hosts. To improve outcome, the diagnosis must be recognized early, before the organism can invade the central nervous system or vascular structures. Aggressive surgical resection of the infected areas is of utmost importance in the management of this infection.

Granulocyte colony-stimulating factor and azole antifungal therapy in murine aspergillosis: role of immune suppression

Outbred ICR mice were immune suppressed either with hydrocortisone or with 5-fluorouracil and were infected intranasally with Aspergillus fumigatus. Beginning 3 days before infection some groups of mice were given recombinant human granulocyte colony-stimulating factor (G-CSF), SCH56592 (an antifungal triazole), or both. Corticosteroid-pretreated mice responded to SCH56592 and had reduced counts in lung tissue and prolonged survival. In these mice, G-CSF strongly antagonized the antifungal activity of SCH56592. Animals treated with both agents developed large lung abscesses with polymorphonuclear leukocytes and large amounts of Aspergillus. In contrast, mice made neutropenic with 5-fluorouracil and then infected with A. fumigatus conidia benefited from either G-CSF or triazoles, and the effect of the combination was additive rather than antagonistic. Host predisposing factors contribute in different ways to the outcome of growth factor therapy in aspergillosis.

Development of liposomal amphotericin B formulation

A considerable effort has been spent in the past three decades to investigate various aspects of liposomes as novel drug delivery systems. In 1990, the first amphotericin B (AmB) liposomal preparation (L-AmB) under the brand name AmBisome was introduced into the market by Vestar. The successful marketing of the product moved liposomes out of the stage of experimental obscurity to the realistic stage of clinical utility. The launch of AmBisome sparked off the introduction of other lipid-based AmB products marketed by Liposome Technology (Amphocil) and The Liposome Co. (Abelcet). The drive behind the development of a modified formulation of AmB was to improve the therapeutic index of this drug with respect to its major drawback associated with both acute and chronic toxic effects. In a 30-year-long experience with AmB, several reports were recorded in the literature of acute adverse effects, such as fever, rigors, vomiting, cardiotoxicity and hypotension occurring during infusion; while long-term therapy was reported to be associated with hypokalemia, renal dysfunction and hematological abnormalities. Another serious problem encountered with the drug had been the poor response obtained in immunocompromised patients like those with AIDS, neutropenia and cancer patients on chemotherapy. The encapsulation of amphotericin B in liposomal vesicles was hence targeted not only to obtain an improvement in the therapeutic index but also to see if it was useful in eradicating deep-seated fungal infections in immunocompromised patients. The liposomal AmB was found to have a better therapeutic index and lower toxicity than the commercial AmB preparations. The LD50 of AmBisome in mouse was 175 mg/kg compared with 3.7 mg/kg for Fungizone, the commercial preparation of AmB. Additionally, L-AmB has prolonged circulation time, and extravasates into the site of infection and delivers the drug directly to the site, with no nephrotoxicity and neurotoxicity as experienced with AmB. This review traces the course of development of L-AmB and discusses the rationale behind the development of its liposomal preparation. The results in in vitro, in vivo and clinical studies, mechanism of action, biodistribution, and formulation considerations of L-AmB are described. The clinical experience with the marketed preparation is reviewed.