High-dose caspofungin as a component of combination antifungal therapy in 91 patients with neoplastic diseases and hematopoietic stem cell transplantation: a critical review of short-term and long-term adverse events

The Impact of Corticosteroids on the Outcome of Fungal Disease: a Systematic Review and Meta-analysis

Purpose of Review

Corticosteroids have a complex relationship with fungal disease - risk for many, benefit for others. This systematic review aims to address the effect of corticosteroids on mortality and visual outcome in different fungal diseases.

Recent Findings

Corticosteroids are a risk factor of aspergillosis for patients who have COVID-19, and they also led to a worse outcome. Similarity, corticosteroids are a risk factor for candidemia and mucormycosis. Some researchers reported that using topical corticosteroid in keratitis was associated with worse visual outcome if fungal keratitis. Some studies showed that corticosteroids are linked to a negative outcome for non-HIV patients with Pneumocystis jirovecii pneumonia (PCP), in contrast to those with HIV and PCP.

Summary

In 59 references, we found that corticosteroid therapy showed a worse clinical outcome in invasive aspergillosis (IA) (HR: 2.50, 95%CI: 1.89-3.31, p < 0.001) and chronic pulmonary aspergillosis (CPA) (HR: 2.74, 95%CI: 1.48-5.06, p = 0.001), PCP without HIV infection (OR: 1.29, 95%CI: 1.09-1.53, p = 0.003), invasive candidiasis and candidaemia (OR: 2.13, 95%CI: 1.85-2.46, p < 0.001), mucormycosis (OR: 4.19, 95%CI: 1.74-10.05, p = 0.001) and early in the course of fungal keratitis (OR: 2.99, 95%CI: 1.14-7.84, p = 0.026). There was equivocal outcome in cryptococcal meningoencephalitis in AIDS and primary coccidioidomycosis, while corticosteroid therapy showed a better outcome in PCP in HIV-infected patients (RR: 0.62, 95%CI: 0.46-0.83, p=0.001) and fungal keratitis patients after keratoplasty surgery (OR: 0.01, 95%CI: 0.00-0.41, p = 0.041) and probably in cryptococcal meningoencephalitis in non-immunocompromised patients. A sub-analysis in invasive aspergillosis and CPA showed that use of more than 2 mg/kg/day of prednisolone equivalents per day is a significant factor in increasing mortality (HR: 2.94, 95%CI: 2.13-4.05, p < 0.001). Corticosteroid therapy during invasive fungal disease was usually associated with a slightly or greatly increased mortality or worse visual outcome (in fungal keratitis), with two disease exceptions. Avoiding the addition of corticosteroids, or minimising dose and duration in those who require them, is likely to improve the outcome of most life- and vision-threatening fungal diseases. This review provides a cornerstone for further research in exploring the accuracy of suitable dose and duration of corticosteroids treatment in fungal diseases.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12281-023-00456-2.

Rezafungin versus Caspofungin in a Phase 2, Randomized, Double-Blind Study for the Treatment of Candidemia and Invasive Candidiasis- The STRIVE Trial

Background

Rezafungin (RZF) is a novel echinocandin exhibiting distinctive pharmacokinetics/pharmacodynamics. STRIVE was a phase 2, double-blind, randomized trial designed to compare the safety and efficacy of RZF once weekly (QWk) to caspofungin (CAS) once daily for treatment of candidemia and/or invasive candidiasis (IC).

Methods

Adults with systemic signs and mycological confirmation of candidemia and/or IC were randomized to RZF 400 mg QWk (400 mg), RZF 400 mg on week 1 then 200 mg QWk (400/200 mg), or CAS 70 mg as a loading dose followed by 50 mg daily for ≤4 weeks. Efficacy assessments included overall cure (resolution of signs of candidemia/IC + mycological eradication) at day 14 (primary endpoint), investigator-assessed clinical response at day 14, and 30-day all-cause mortality (ACM) (secondary endpoints), and time to negative blood culture. Safety was evaluated by adverse events and ACM through follow-up.

Results

Of 207 patients enrolled, 183 were in the microbiological intent-to-treat population (~21% IC). Overall cure rates were 60.5% (46/76) for RZF 400 mg, 76.1% (35/46) for RZF 400/200 mg, and 67.2% (41/61) for CAS; investigator-assessed clinical cure rates were 69.7% (53/76), 80.4% (37/46), and 70.5% (43/61), respectively. In total, 30-day ACM was 15.8% for RZF 400 mg, 4.4% for RZF 400/200 mg, and 13.1% for CAS. Candidemia was cleared in 19.5 and 22.8 hours in RZF and CAS patients, respectively. No concerning safety trends were observed; ACM through follow-up was 15.2% (21/138) for RZF and 18.8% (13/69) for CAS.

Conclusions

RZF was safe and efficacious in the treatment of candidemia and/or IC.

Clinical Trials Registration

NCT02734862

Extrapolating Antifungal Animal Data to Humans - Is it reliable?

PURPOSE OF REVIEW

This article aimed to review animal models of antifungals and identifies human literature to assess if the extrapolation of results is reliable.

RECENT FINDINGS

Animal studies have helped identify AUC/MIC targets for new drugs and formulations such as isavuconazole and delayed release posaconazole that have translated to successful outcomes in humans. Models have also been influential in the identification of possible combination therapies for the treatment of aspergillosis, such as voriconazole and echinocandins. However, challenges are endured with animal models when it comes to replicating the pharmacokinetics of humans which has been exemplified with the newest itraconazole formulation. Additionally, animal models have displayed a survival benefit with the use of iron chelators and amphotericin for mucormycosis which was not demonstrated in humans.

SUMMARY

Animal models have been a staple in the development and optimization of antifungal agents. They afford the ability to investigate uncommon diseases, such as invasive fungal infections, that would otherwise take years and many resources to complete. Although there are many benefits of animal models there are also shortcomings. This is why the reliability of extrapolating data from animal models to humans is often scrutinized.

Recent Insights into the Paradoxical Effect of Echinocandins

Echinocandin antifungals represent one of the most important drug classes for the treatment of invasive fungal infections. The mode of action of the echinocandins relies on inhibition of the β-1,3-glucan synthase, an enzyme essentially required for the synthesis of the major fungal cell wall carbohydrate β-1,3-glucan. Depending on the species, echinocandins may exert fungicidal or fungistatic activity. Apparently independent of this differential activity, a surprising in vitro phenomenon called the “paradoxical effect” can be observed. The paradoxical effect is characterized by the ability of certain fungal isolates to reconstitute growth in the presence of higher echinocandin concentrations, while being fully susceptible at lower concentrations. The nature of the paradoxical effect is not fully understood and has been the focus of multiple studies in the last two decades. Here we concisely review the current literature and propose an updated model for the paradoxical effect, taking into account recent advances in the field.

The Gastrointestinal Tract Is a Major Source of Echinocandin Drug Resistance in a Murine Model of Candida glabrata Colonization and Systemic Dissemination

Candida species are a part of the human microbiome and can cause systemic infection upon immune suppression. Candida glabrata infections are increasing and have greater rates of antifungal resistance than other species. Here, we present a C. glabrata gastrointestinal (GI) colonization model to explore whether colonized yeast exposed to caspofungin, an echinocandin antifungal, develop characteristic resistance mutations and, upon immunosuppression, breakthrough causing systemic infection. Daily therapeutic dosing (5 mg/kg of body weight) of caspofungin resulted in no reduction in fecal burdens, organ breakthrough rates similar to control groups, and resistance rates (0 to 10%) similar to those reported clinically. Treatment with 20 mg/kg caspofungin initially reduced burdens, but a rebound following 5 to 9 days of treatment was accompanied by high levels of resistance (FKS1/FKS2 mutants). Although breakthrough rates decreased in this group, the same FKS mutants were recovered from organs. In an attempt to negate drug tolerance that is critical for resistance development, we cotreated mice with daily caspofungin and the chitin synthase inhibitor nikkomycin Z. The largest reduction (3 log) in GI burdens was obtained within 3 to 5 days of 20 mg/kg caspofungin plus nikkomycin treatment. Yet, echinocandin resistance, characterized by a novel Fks1-L630R substitution, was identified following 5 to 7 days of treatment. Therapeutic caspofungin plus nikkomycin treatment left GI burdens unchanged but significantly reduced organ breakthrough rates (20%; P < 0.05). Single-dose pharmacokinetics demonstrated low levels of drug penetration into the GI lumen posttreatment with caspofungin. Overall, we show that C. glabrata echinocandin resistance can arise within the GI tract and that resistant mutants can readily disseminate upon immunosuppression.

Combination therapy for the treatment of pulmonary mold infections

INTRODUCTION

Pulmonary mold infections are caused by ubiquitous organisms found in soil, water, and decaying vegetation, including Aspergillus spp., the Mucormycetes, hyaline molds, and dematiaceous (black) molds. Areas covered: These infections are often a challenge to diagnose and even more difficult to treat. Recently, antifungal combination therapy has emerged as a promising strategy to treat some forms of invasive mycoses, including pulmonary mold infections. Historically, this approach has been limited due to non-uniform interpretation criteria, variations in pharmacodynamic/pharmacokinetic properties of antifungals used in combination, and an inability to predict clinical success based on in vitro data and animal models. However, recent advances have helped mitigate some of these challenges. Expert commentary: In this paper, we explore what is known about the antifungal combination therapy in the treatment of pulmonary mold infections and explore how it may impact clinical practice. We pay particular attention to novel combinations and the challenges associated with the development of new antifungal agents.

An update on the safety and interactions of antifungal drugs in stem cell transplant recipients

INTRODUCTION

Invasive fungal diseases (IFDs) are a major cause of morbidity and mortality in patients undergoing allogeneic hematopoietic stem cell transplant (HSCT). Improvement in the management of IFDs have been achieved with the availability of new effective and safe antifungal drugs, however, many of these newer treatments have some limitations in their variable toxicity and unique predisposition for pharmacokinetic drug-drug interactions. Areas covered: This article is an update of a previous review published in this journal evaluating the safety profile of the antifungal drugs. Interesting new features include the availability of the new drug isavuconazole and the new tablet and intravenous formulations of posaconazole. Different dosages and new ways of administration of liposomal Amphotericin B (L-AmB) and echinocandins may be considered in the HSCT practice. Expert opinion: Nephrotoxicity continues to be a clinically relevant and frequent side effect of L-AmB which may cause a reduced clearance of other renally eliminated drugs frequently used in HSCT patients. Echinocandins are favorable therapeutic options in view of their low toxicity and uncommon drug-drug interactions. Important limitations of triazoles are represented by hepatic toxicity and certain side effects particularly after prolonged treatments. The new triazole isavuconazole and the new tablet formulation of posaconazole will be probably increasingly used in the HSCT setting not only due to their efficacy but in particular for their interesting toxicity profile and pharmacokinetic characteristics. The knowledge of these pharmacological findings is crucial in the daily care of allogeneic HSCT patients.

Potential Microbiological Effects of Higher Dosing of Echinocandins

The antifungal "paradoxical effect" has been described as the reversal of growth inhibition at high doses of echinocandins, most usually caspofungin. This microbiological effect appears to be a cellular compensatory response to cell wall damage, resulting in alteration of cell wall content and structure as well as fungal morphology and growth. In vitro studies demonstrate this reproducible effect in a certain percentage of fungal isolates, but animal model and clinical studies are less consistent. The calcineurin and Hsp90 cell signaling pathways appear to play a major role in regulating these cellular and structural changes. Regardless of the clinical relevance of this paradoxical growth effect, understanding the specific actions of echinocandins is paramount to optimizing their use at either standard or higher dosing schemes, as well as developing future improvements in our antifungal arsenal.

[Echinocandins: Applied pharmacology]

The echinocandins share pharmacodynamic properties, although there are some interesting differences in their pharmacokinetic behaviour in the clinical practice. They are not absorbed by the oral route. They have a somewhat special distribution in the organism, as some of them can reach high intracellular concentrations while, with some others, the concentration is reduced. They are highly bound to plasma proteins, thus it is recommended to administer a loading dose for anidulafungin and caspofungin, although this procedure is not yet clear with micafungin. Echinocandins are excreted via a non-microsomal metabolism, so the urinary concentration is very low. Some carrier proteins that take part in the biliary clearance process are probably involved in the interactions described with caspofungin and micafungin. These two drugs must be used with caution in patients with severely impaired hepatic function, while all of them can be used without special precautions when there is renal impairment or the patient requires renal replacement therapy.