Management of chronic pulmonary aspergillosis

Selection of Oral Antifungals for Initial Maintenance Therapy in Chronic Pulmonary Aspergillosis: A Longitudinal Analysis

BACKGROUND

There are limited data for direct comparisons of the efficacy of oral itraconazole (ITCZ) and oral voriconazole (VRCZ) therapy in the treatment of chronic pulmonary aspergillosis (CPA).

METHODS

We conducted a retrospective, follow-up, observational study of CPA patients enrolled in 2 previous multicenter trials.

RESULTS

Of the 273 CPA patients, 59 and 101 patients started maintenance therapy with oral ITCZ and oral VRCZ, respectively, just after the end of acute intravenous therapy in each trial. At the end of the observation period in this follow-up study (median observation period, 731 days), the percentage of patients who showed improvement was lower in the ITCZ group than in the VRCZ group (18.2% vs 40.0%). However, after including stable patients, the percentages were 50.9% and 52.6%, respectively, in the ITCZ and VRCZ groups, which were not significantly different (P = .652). Multivariable Cox regression analysis showed no significant influence of the choice of initial maintenance treatment (ITCZ or VRCZ) on overall mortality as well as CPA-associated mortality. Multivariable logistic regression showed that oral ITCZ selection for initial maintenance therapy was an independent risk factor for hospital readmission and switching to other antifungal agents (odds ratio [OR], 3.1; 95% confidence interval [CI], 1.3-7.5 and OR, 5.7; 95% CI, 2.0-15.7, respectively).

CONCLUSIONS

Oral VRCZ for initial maintenance therapy showed better effectiveness than oral ITCZ for clinical improvement in CPA patients. There was no difference in crude mortality between initial maintenance therapy with VRCZ and ITCZ, especially in elderly CPA patients.

CLINICAL TRIALS REGISTRATION

UMIN000007055.

Role of FKS Gene in the Susceptibility of Pathogenic Fungi to Echinocandins

Echinocandins are antifungal agents that specifically inhibit the biosynthesis of 1,3-β-D-glucan, a major structural component of fungal cell walls. Echinocandins are recommended as first-line or alternative/salvage therapy for candidiasis and aspergillosis in antifungal guidelines of various countries. Resistance to echinocandins has been reported in recent years. The mechanism of echinocandin resistance involves amino acid substitutions in hot spot regions of the FKS gene product, the catalytic subunit of 1,3-β-D-glucan synthase. This resistance mechanism contributes to not only acquired resistance in Candida spp., but also inherent resistance in some pathogenic fungi. An understanding of the echinocandin resistance mechanism is important to develop both effective diagnosis and treatment options for echinocandin-resistant fungal diseases.

The Current Status of Drug-resistant Aspergillus

Aspergillus spp. are important fungi because of the high mortality associated with aspergillosis. However, we have only three classes of anti-aspergillus drugs available; and only two drugs, itraconazole (ITCZ) and voriconazole (VRCZ), are available as oral agents in Japan. If azole-resistant Aspergillus causes chronic aspergillosis, we cannot treat such patients with oral azoles on an outpatient basis. As is the case with foreign countries, we found the existence of azole-resistant Aspergillus fumigatus in clinical settings in Japan. Resistance was attributed to mutations of the target protein (CYP51A). Additionally, we also found that long-term itraconazole treatment induced G54 substitution in CYP51A, causing itraconazole-resistance. Although there are few resistant Aspergillus strains existing in Japan now, we have to continue to find such resistant isolates, which are spreading worldwide.

Chronic Pulmonary Aspergillosis-Where Are We? and Where Are We Going?

Chronic pulmonary aspergillosis (CPA) is estimated to affect 3 million people worldwide making it an under recognised, but significant health problem across the globe, conferring significant morbidity and mortality. With variable disease forms, high levels of associated respiratory co-morbidity, limited therapeutic options and prolonged treatment strategies, CPA is a challenging disease for both patients and healthcare professionals. CPA can mimic smear-negative tuberculosis (TB), pulmonary histoplasmosis or coccidioidomycosis. Cultures for Aspergillus are usually negative, however, the detection of Aspergillus IgG is a simple and sensitive test widely used in diagnosis. When a fungal ball/aspergilloma is visible radiologically, the diagnosis has been made late. Sometimes weight loss and fatigue are predominant symptoms; pyrexia is rare. Despite the efforts of the mycology community, and significant strides being taken in optimising the care of these patients, much remains to be learnt about this patient population, the disease itself and the best use of available therapies, with the development of new therapies being a key priority. Here, current knowledge and practices are reviewed, and areas of research priority highlighted.

Recent advances in chronic pulmonary aspergillosis

Chronic pulmonary aspergillosis (CPA) is a slowly progressing pulmonary syndrome caused by Aspergillus spp. Specific knowledge regarding the disease entity, diagnosis method, and management is needed. This review focuses on the recent advances in our understanding of CPA. A new clinical disease entity of chronic progressive pulmonary aspergillosis consisting of chronic necrotizing pulmonary aspergillosis and chronic cavitary pulmonary aspergillosis is proposed. Although newer antifungals are not available, evidence describing the treatment of CPA is accumulating. Longer administration of azoles is required for a better prognosis, but there is a risk of inducing azole resistance. Therapeutic drug monitoring and patient education are required. Establishing a drug-susceptibility test that can be performed in the general laboratory and the referral center are also important. Although the number of publications regarding CPA is growing, there are still many unanswered questions. Additional evidence and translational research regarding diagnosis, management, and drug resistance are urgently needed to improve the outcome of CPA.

Chronic Aspergillosis of the Lungs: Unravelling the Terminology and Radiology

The propensity for Aspergillus spp. to cause lung disease has long been recognised but the satisfactory classification of these disorders is challenging. The problems caused by invasive disease in severely neutropenic patients, saprophytic infection of pre-existing fibrotic cavities and allergic reactions to Aspergillus are well documented. In contrast, a more chronic form of Aspergillus-related lung disease that has the potential to cause significant morbidity and mortality is under-reported. The symptoms of this form of Aspergillus infection may be non-specific and the radiologist may be the first to suspect a diagnosis of chronic pulmonary aspergillosis. The current review considers the classification conundrums in diseases caused by Aspergillus spp. and discusses the typical clinical and radiological profile of patients with chronic pulmonary aspergillosis.

KEY POINTS

• The classification of Aspergillus -related lung disease is mired in confusion. • The chronic form of Aspergillus infection is associated with significant morbidity and mortality. • Progressive consolidation and cavitation with intracavitary material is the radiological hallmark.

Chronic pulmonary aspergillosis

Chronic pulmonary aspergillosis (CPA) is a group of consuming diseases usually presenting with prolonged and relapsing cough, dyspnoea and weight loss. Acute symptoms such as haemoptysis and bronchial or pulmonary haemorrhage may occasionally occur. CPA affects patients with underlying pulmonary conditions, for example, chronic obstructive pulmonary disease or mycobacteriosis or common immunosuppressive conditions such as diabetes. Precise epidemiology is unknown, and while prevalence is considered low the chronic and relapsing nature of the disease challenges the treating physician. Diagnostics largely rely on serologic Aspergillus precipitins and findings on thoracic computed tomography. The latter are manifold comprising cavity formation, pleural involvement and sometimes aspergilloma. Other markers for aspergillosis are less helpful, in part due to the non- or semi-invasive nature of these forms of Aspergillus infection. Various antifungals were shown to be effective in CPA treatment. Azoles are the most frequently applied antifungals in the outpatient setting, but are now compromised by findings of Aspergillus resistance. Long-term prognosis is not fully elucidated and may be driven by the underlying morbidities. Prospective registry-type studies may be suitable to systematically broaden our CPA knowledge base. This article gives an overview of the available literature and proposes a clinical working algorithm for CPA management.