An evaluation of ibrexafungerp for the treatment of invasive candidiasis: the evidence to date

Synthesis and evaluation of the antifungal activity of 5-hydroxy-3-phenyl-1H-pyrazole-1-carbothioamide for use in the oral environment

Background and aim

Candida albicans and Candida tropicalis, can cause superficial infections of the oral mucosa as well as disseminated bloodstream and deep-tissue infections. The most frequently employed class of antifungals used for Candida infection treatment are the azole antifungals. Their low price, low toxic qualities, and availability for oral use make fluconazole and similar azole antifungals the preferred treatment for various infections caused by Candida. Nevertheless, developed and intrinsic resistance to antifungals of the azole family has been widely documented in association with various species of Candida. Candida infection management requires synthesizing new compounds to improve azole class antifungals, as Candida isolates resistant to azole are increasingly encountered in the clinical setting. This study aimed to synthesize a new azole compound and investigate its antifungal activity.

Methods

In this experimental study, 5-hydroxy-3-phenyl-1H-pyrazole-1-carbothioamide was synthesized by the reaction between thiosemecarbazide and ethylbezoylacetate. The structure of the synthesized compound was characterized by different techniques such as Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectra and its antifungal activity against Candida albicans and Candida tropicalis was investigated by the Spread Plat method to determine its minimum fungicidal concentration (MFC) and minimum inhibitory concentration (MIC).

Results and discussion

The Spread Plat test demonstrated that with the increase in 5-hydroxy-3-phenyl-1H-pyrazole-1-carbothioamide concentration, colonies of fungi were increasingly eliminated at a significant level(p < 0.001). At a concentration of 1000 ppm, all Candida albicans and Candida tropicalis colonies were destroyed.

Conclusions

The results indicate that the synthesized compound showed a promising antifungal effect. On the other hand, it had a suitable spectrum of effect, because it showed antifungal effects on both Candida albicans and Candida tropicalis strains.

Candida auris, a singular emergent pathogenic yeast: its resistance and new therapeutic alternatives

Nowadays, fungal infections affect millions of people across the world. Candida auris, a new emergent yeast, is a worrisome pathogen because it associates with a high rate of incidence and prevalence, including in the nosocomial environment. The hard identification, the phenotypic plasticity, and the easy adaptation to stressful conditions are some of the C. auris traits that render this latest yeast singular challenging. C. auris infections have already been reported from more than 30 countries and are associated with high mortality rates. This is the result from rapid transmission and the difficulty of prevention, control, and eradication. There are several factors related to the high virulence of C. auris, such as the multidrug resistance, biofilm development, and the ability to escape the response of the innate immune system. So, C. auris infections are a serious and alarming problem, not only because of the high pathogenicity of the fungal agent but also because of the low effectiveness of the treatments available. Although new formulations have been developed against C. auris strains, a better understanding is essential to efficiently treat, prevent, and control C. auris infections.

Investigational Antifungal Agents for Invasive Mycoses: A Clinical Perspective

Treatment of invasive fungal infections (IFIs) remains challenging, because of the limitations of the current antifungal agents (ie, mode of administration, toxicity, and drug-drug interactions) and the emergence of resistant fungal pathogens. Therefore, there is an urgent need to expand our antifungal armamentarium. Several compounds are reaching the stage of phase II or III clinical assessment. These include new drugs within the existing antifungal classes or displaying similar mechanism of activity with improved pharmacologic properties (rezafungin and ibrexafungerp) or first-in-class drugs with novel mechanisms of action (olorofim and fosmanogepix). Although critical information regarding the performance of these agents in heavily immunosuppressed patients is pending, they may provide useful additions to current therapies in some clinical scenarios, including IFIs caused by azole-resistant Aspergillus or multiresistant fungal pathogens (eg, Candida auris, Lomentospora prolificans). However, their limited activity against Mucorales and some other opportunistic molds (eg, some Fusarium spp.) persists as a major unmet need.

Pharmacokinetics and Pharmacodynamics of Ibrexafungerp

On 2 June, 2021, the US Food and Drug Administration approved ibrexafungerp (formerly MK-3118 and SCY-078) for the treatment of vulvovaginal candidiasis, also known as vaginal yeast infection. Ibrexafungerp is the first drug approved in a novel antifungal class in more than two decades, and the Food and Drug Administration’s decision was based on positive results from two pivotal phase III studies in which oral ibrexafungerp proved both safe and effective in patients with vulvovaginal candidiasis. The decision was also based on substantial preclinical and clinical work in both the pharmacokinetics and pharmacodynamics of ibrexafungerp. This paper reviews that research and looks ahead to explore how this novel antifungal agent may be used in the future to address the expanding problem of drug-resistant mycotic infections.