Posaconazole pharmacokinetics in a 2-year-old boy with rhino-cerebral-orbital zygomycosis

Lack of surgical resection is associated with increased early mortality in hematological patients complicated with rhino-orbital-cerebral mucormycosis

Rhino-orbital-cerebral mucormycosis (ROCM), which is an acute fatal infectious disease with a high mortality rate, is increasingly being diagnosed in patients with hematological diseases worldwide. We aimed to investigate the clinical characteristics, treatment, and prognosis of hematological diseases complicated by ROCM. Our sample comprised a total of 60 ROCM patients with hematological diseases. The most common primary disease was acute lymphoblastic leukemia (ALL) (n=27, 45.0%), while 36 patients (60.0%) were diagnosed with a clear type of pathogen, all belonging to the Mucorales, most commonly Rhizopus (41.7%). Of the 32 patients (53.3%) who died, 19 (59.3%) died of mucormycosis, and 84.2% (n=16) of those died within 1 month. Forty-eight cases (80.0%) received antifungal treatment combined with surgical therapy, 12 of whom (25.0%) died of mucormycosis, amounting to a mortality rate that was significantly lower than in patients who received antifungal therapy alone (n=7, 58.3%) (P=0.012). The median neutrophil value of patients who underwent surgery was 0.58 (0.11-2.80) 103/μL, the median platelet value was 58.00 (17.00-93.00) 103/μL, and no surgery-related deaths were reported. Multivariate analysis showed that patient's advanced age (P=0.012, OR=1.035 (1.008-1.064)) and lack of surgical treatment (P=0.030, OR=4.971 (1.173-21.074)) were independent prognostic factors.In this study, hematological diseases associated with ROCM have a high mortality rate. Lack of surgical treatment is an independent prognostic factor for death from mucormycosis. Surgery may therefore be considered in patients with hematological disease even if their neutrophil and platelet values are lower than normal.

Rhino-Orbital-Cerebral Mycosis and Extranodal Natural Killer or/and T-Cell Lymphoma, Nasal Type

Background

Extranodal natural killer/T-cell lymphoma, nasal type is a syndrome of middle face destruction with an association to Epstein-Barr virus. Fungi have been recovered from the diseased tissue now and then but were often seen as a lymphoma-associated secondary infection. However, there are ENKTL-NT cases with the recoveries of fungi and complete recovery with antifungal therapy, which are quite similar to rhino-orbital-cerebral mycosis (ROCM) that often confuses the physicians.

Methods

We searched Medline for English-language manuscripts limited to “human” and “case reports,” “letters,” “reviews,” and “clinical conferences” from 1966 to 2022. We used MeSH terms “lymphoma, extranodal nk-t-cell” [MeSH Terms] or “lethal midline granuloma” [MeSH Terms], in combination with MeSH terms “microbiology” [subheading] or “microbiology” [all fields] or “fungi” [all fields] or “fungi” [MeSH Terms] for ENKTL-NT with infections. We used MeSH terms “Mycoses” in combination with “Nose” [Mesh] OR “Orbital Diseases” [Mesh] for rhino-orbital-cerebral fungal infections.

Results

We appraised 149 included articles and extracted references related to ENKTL-NT and/or ROCM. Themes and subcategories were subsequently derived. Our findings revealed that ROCM and ENKTL-NT are characterized by progressive and destructive ulcers in the midline face or rhino-orbital structures. ROCM is mainly caused by fungi in the order of Mucorales, and ENKTL-NT is usually associated with Epstein-Barr virus and sometimes fungi. Radiologically, both are characterized by non-specific features of sinusitis, soft tissue infection, and necrosis. Pathologically, ROCM and ENKTL-NT share the same characteristics of inflammation, necrosis, and granuloma. ROCM is characterized by the detection of fungi in tissue, while ENKTL-NT is typically positive for NK/T-cell markers and cytotoxic granule-associated proteins, proliferation, and vascular damage of angioinvasion, which could be incited by Mucor irregularis and Rhizopus arrhizus in patients and mice.

Conclusion

ENKTL-NT and ROCM share many similarities in clinical presentations, radiology, and histopathology, and might have the same etiology. This may explain why the two diseases are tangled together in the reported cases, and suggests the role that the fungi may play in the development of these ENKTL-NT/ROCM diseases. The reason why ENKTL-NT and ROCM are sometimes confused is that the main pathogens of ROCM, Mucor irregularis and Rhizopus arrhizus, are the fungal causative agents of ENKTL-NT.

Case Report: Rhizopus arrhizus Rhino-Orbital-Cerebral Mycosis and Lethal Midline Granuloma: Another Fungal Etiological Agent

Objective: Both rhino-orbital-cerebral mycosis and lethal midline granuloma (LMG) may result in midline destruction. LMG has now been generally considered as a natural killer/T cell lymphoma, nasal type (ENKTL-NT) with an association of EBV. Fungi have been detected from the diseased tissues now and then but are often considered as lymphoma-associated infections. We previously reported an ENKTL-NT case with Mucor irregularis, which played a causal role in the disease and was involved in the overexpression of Ki67 and CD56 in the mouse experiment. The present study describes a chronic Rhizopus arrhizus infection with immunological parameters that are closely similar to LMG. We aim to explore the relationship of another Mucorales fungus, R. arrhizus, and LMG in a patient and in mice. Methods: Case study and mouse infection modules were designed for our observation. A 35-year-old man with midline face ulcers which was clinically suspected as LMG was selected. Biopsy specimens were sent for lymphoma diagnosis and microbiological detection. The isolated fungus was tested in an ICR mouse model for mycological and histological analyses. Results: Five tissue samples yielded Rhizopus arrhizus. In the pathology, characteristic inflammation, necrosis, and granulation with thin-walled hyphae are observed. Immunohistochemistry showed NK/T cell infiltration (CD3+, CD8+, TIA1+, GZMB+, PRF+, individual CD56+) with hyperplasia (Ki67+) and angioinvasion. The patient recovered completely with amphotericin B. In the murine experiment, R. arrhizus caused angioinvasion with NK/T cell infiltration (CD3+, CD56+, TIA1+, GZMB +, PRF+) with proliferation (Ki67+) and was re-isolated from the infected host. Conclusions: We here describe a mid-face destruction patient, which was diagnosed by the top pathologists in China according to the current criteria of NK/T cell lymphoma, with a negative result for EBV and positive result for R. arrhizus. With a then developed mouse experiment, the R. arrhizus in the diseased lesions was responsible for the NK/T cell infiltration (CD3+, CD8+, CD56+, TIA1+, GZMB+, PRF+), proliferation (Ki67+), and angioinvasion, suggesting another fungal etiological agent for LMG, which could be eradicated with amphotericin B. Limitations: The sample size is not sufficient for statistical analysis. However, our findings are suggestive for the role fungus plays in LMG.

Successful posaconazole salvage therapy for rhinocerebral mucormycosis in a child with leukemia. Review of the literature

BACKGROUND

Mucormycosis is a fungal infection caused by species of the Mucorales order. These microorganisms are angioinvasive, with rapid disease progression and potentially lethal in its rhinocerebral form.

CASE REPORT

We present the case of a 12-year-old female with trisomy 21, acute lymphoblastic leukemia and diabetes, with fever and neutropenia who developed rhinocerebral mucormicosis. After treatment with amphotericin B lipid complex and extensive surgery, disease progressed and posaconazole was added as salvage treatment with full remission of the infection. Four years after diagnosis the patient continues without relapse of mucormycosis or leukemia.

CONCLUSIONS

This case highlights the use of posaconazole as either monotherapy or combined therapy. Although it is still debated, it can be considered an option for salvage treatment in children with non-responding mucormycosis, despite lack of standard dosage in pediatric patients.

Therapeutic drug monitoring of posaconazole oral suspension in paediatric patients younger than 13 years of age: a retrospective analysis and literature review

WHAT IS KNOWN AND OBJECTIVE

Posaconazole is an extended-spectrum triazole antifungal with activity against a variety of clinically significant yeasts and moulds. Posaconazole is not currently approved by the U.S. Food and Drug Administration for use in children younger than 13 years of age. Our primary objective was to describe the dosing and observed trough concentrations with posaconazole oral suspension in paediatric patients at the National Institutes of Health Clinical Center (Bethesda, MD).

METHODS

This retrospective single-centre study reviewed paediatric patients younger than 13 years of age initiated on posaconazole oral suspension. Patients were included if they were initiated on posaconazole for prophylaxis or treatment for fungal infections from September 2006 through March 2013 with at least one trough concentration collected after at least 7 days of therapy.

RESULTS AND DISCUSSION

A total of 20 male patients were included, of whom 15 (75%) had chronic granulomatous disease. The median age of patients was 6·5 years (range: 2·8-10·7). A total of 79 posaconazole trough concentrations were measured in patients receiving posaconazole as prophylaxis (n = 8) or treatment (n = 12). Posaconazole dose referenced to total body weight ranged from 10·0 to 49·2 mg/kg/day. Posaconazole trough concentrations ranged from undetectable (<50 ng/mL) up to 3620 ng/mL and were ≥500, ≥700 and ≥1250 ng/mL in 95%, 60% and 25% of patients, respectively.

WHAT IS NEW AND CONCLUSIONS

Patients younger than 13 years of age had highly variable trough concentrations, and recommendations for the appropriate dosing of posaconazole oral suspension remain challenging. Until studies are conducted to determine the appropriate dosing of posaconazole in this patient population, therapeutic drug monitoring should be considered to ensure adequate posaconazole exposure.

Trypanosoma brucei CYP51: Essentiality and Targeting Therapy in an Experimental Model

Trypanosoma brucei gambiense is the main causative agent of Human African Trypanosomiasis (HAT), also known as sleeping sickness. Because of limited alternatives and treatment toxicities, new therapeutic options are urgently needed for patients with HAT. Sterol 14alpha-demethylase (CYP51) is a potential drug target but its essentiality has not been determined in T. brucei. We used a tetracycline-inducible RNAi system to assess the essentiality of CYP51 in T. brucei bloodstream form (BSF) cells and we evaluated the effect of posaconazole, a well-tolerated triazole drug, within a panel of virulent strains in vitro and in a murine model. Expression of CYP51 in several T. brucei cell lines was demonstrated by western blot and its essentiality was demonstrated by RNA interference (CYP51RNAi) in vitro. Following reduction of TbCYP51 expression by RNAi, cell growth was reduced and eventually stopped compared to WT or non-induced cells, showing the requirement of CYP51 in T. brucei. These phenotypes were rescued by addition of ergosterol. Additionally, CYP51RNAi induction caused morphological defects with multiflagellated cells (p<0.05), suggesting cytokinesis dysfunction. The survival of CYP51RNAi Doxycycline-treated mice (p = 0.053) and of CYP51RNAi 5-day pre-induced Doxycycline-treated mice (p = 0.008) were improved compared to WT showing a CYP51 RNAi effect on trypanosomal virulence in mice. The posaconazole concentrations that inhibited parasite growth by 50% (IC50) were 8.5, 2.7, 1.6 and 0.12 μM for T. b. brucei 427 90-13, T. b. brucei Antat 1.1, T. b. gambiense Feo (Feo/ITMAP/1893) and T. b. gambiense Biyamina (MHOM/SD/82), respectively. During infection with these last three virulent strains, posaconazole-eflornithine and nifurtimox-eflornithine combinations showed similar improvement in mice survival (p≤0.001). Our results provide support for a CYP51 targeting based treatment in HAT. Thus posaconazole used in combination may represent a therapeutic alternative for trypanosomiasis.

Posaconazole: promising but problematic in practice in pediatric patients

Posaconazole is a broad-spectrum antifungal agent used for the prevention and treatment of invasive fungal infections. It is currently only licensed for use in children greater than 12 years of age. Absorption of the oral formulation is unpredictable and affected by mucositis and concomitant medications. We reviewed studies of posaconazole use in children younger than 12 years in relation to attainment of target serum concentrations.

Mucormycosis in children: a study of 22 cases in a Mexican hospital

We present a single-centre, retrospective study (1985-2012) of 22 cases of mucormycosis in children. A total of 158 mucormycosis cases were identified, of which 22 (13.96%) were children. The mean age of the children was 10.3 years (range: 6 months-18 years), and 59% of the infections occurred in males. The rhinocerebral form was the main clinical presentation (77.27%), followed by the primary cutaneous and pulmonary patterns. The major underlying predisposing factors were diabetes mellitus in 68.18% of the patients and haematologic diseases in 27.7% of the patients. The cases were diagnosed by mycological tests, with positive cultures in 95.4% of the patients. Rhizopus arrhizus was the foremost aetiologic agent in 13/22 cases (59.1%). In 21 cultures, the aetiologic agents were identified morphologically and by molecular identification. In 10 cultures, the internal transcribed spacer region of the ribosomal DNA was sequenced. Clinical cure and mycological cure were achieved in 27.3% cases, which were managed with amphotericin B deoxycholate and by treatment of the underlying conditions.

Mind the gap: Management of an emergent and threatening invasive fungal infection-a case report of rhino-orbital-cerebral and pulmonary mucormycosis

Mucormycosis is an emergent and threatening invasive fungal invasion underdiagnosed by clinicians due to lack of awareness and aspecific clinical picture. The authors describe a clinical case of a diabetic and cirrhotic patient who developed rhino-orbital-cerebral and pulmonary mucormycosis, non-responsive to treatment. Typical gaps in the management of this deadly disease are addressed. There is a strong need for novel therapies and an expectation that sponsors will recognize the critical need for randomized clinical trials.