In Vitro pH Activity of Ibrexafungerp against Fluconazole-Susceptible and -Resistant Candida Isolates from Women with Vulvovaginal Candidiasis

Identification and antifungal susceptibility patterns of reference yeast strains to novel and conventional agents: a comparative study using CLSI, EUCAST and Sensititre YeastOne methods

Objectives

The aim of this study was to identify and determine the MICs of 13 antifungal drugs, including the novel agents ibrexafungerp, manogepix and rezafungin, against 22 laboratory reference strains from 14 different Candida spp. and allied yeast genera using the EUCAST, CLSI and Sensititre™ YeastOne™ (SYO) methods.

Results

Complete agreement between molecular and proteomics methods was observed for identification. The compounds with the greatest in vitro activity, as indicated by the lowest geometric mean MIC (GM), were manogepix (GM: 0.01), isavuconazole (GM: 0.05) and rezafungin (GM: 0.03-0.07). The overall essential agreement (EA) (within ±0 to ±2 2-fold dilutions) between the reference methods, EUCAST and CLSI, was 95%, with results ranging from 82% (ibrexafungerp) to 100% (amphotericin B, anidulafungin, fluconazole, 5-flucytosine and micafungin). Regarding EA for EUCAST and CLSI compared with SYO, values were 91% and 89%, respectively. Nevertheless, when the MIC values were transformed into log2, significant differences were observed (e.g. fluconazole, ibrexafungerp and 5-flucytosine). At the species level, Candidozyma auris and Candida duobushaemulonii exhibited the highest number of cases with significant differences when comparing the three techniques for each antifungal.

Conclusions

The high EA observed reinforces the reliability of EUCAST, CLSI and SYO in guiding antifungal therapy. However, the differences in EA, particularly for ibrexafungerp and 5-flucytosine, highlight the importance of continued evaluation of these methodologies to ensure consistency. Given that antifungal susceptibility testing plays a critical role in treatment decisions, understanding these variations is essential to prevent potential misclassification of susceptibility profiles, which could impact clinical outcomes.

Antifungal Testing of Vaginal Candida Isolates in Pregnant Women: A Retrospective, Single-Center Study in Adana, Türkiye

Clinical and mycological data are essential for the optimal management of patients with Candida vaginitis (CV), particularly in cases of (i) azole-resistant C. albicans vaginitis, (ii) recurrent CV, and (iii) CV in pregnant women. The present retrospective single-center study investigated the antifungal activity of six commonly used antifungals against randomly selected vaginal isolates recovered from 68 pregnant women in Adana, Türkiye, including C. albicans, petite C. glabrata, non-petite C. glabrata, and C. krusei, using the disk diffusion method at pH 4 and 7. Furthermore, the antifungal activities of fluconazole and itraconazole were also assessed using the broth microdilution method. For all isolates, the mean inhibition zone diameters were narrower for itraconazole and ketoconazole and larger for miconazole at pH 4 than pH 7 (p < 0.05). For nystatin, zone diameters were wider in C. albicans and petite C. glabrata at pH 4 (p < 0.001 and p < 0.001). Remarkably, clotrimazole was more active at pH 4 than at pH 7, except against non-petite C. glabrata isolates. Based on the broth microdilution results, the resistance rate was higher at pH 4 than at pH 7 in all isolates. Candida glabrata petite isolates exhibited MIC values 2 to 5 times higher than those of the non-petite isolates for both fluconazole and itraconazole. This study highlights the potent activity of topical antifungals (miconazole, nystatin, and clotrimazole) for the treatment of CV in pregnant women and highlights the need to identify petite and non-petite mutants of vaginal C. glabrata isolates to obtain more reliable data and for antifungal susceptibility testing prior to decision-making. The results of the two antifungal susceptibility methods were compared for C. albicans and C. glabrata isolates, and the reliability of the disk diffusion test was discussed.

New Ground in Antifungal Discovery and Therapy for Invasive Fungal Infections: Innovations, Challenges, and Future Directions

This review explores current advancements and challenges in antifungal therapies amid rising fungal infections, particularly in immunocompromised patients. We detail the limitations of existing antifungal classes-azoles, echinocandins, polyenes, and flucytosine-in managing systemic infections and the urgent need for alternative solutions. With the increasing incidence of resistance pathogens, such as Candida auris and Aspergillus fumigatus, we assess emerging antifungal agents, including Ibrexafungerp, T-2307, and N'-Phenylhydrazides, which target diverse fungal cell mechanisms. Innovations, such as nanoparticles, drug repurposing, and natural products, are also evaluated for their potential to improve efficacy and reduce resistance. We emphasize the importance of novel approaches to address the growing threat posed by fungal infections, particularly for patients with limited treatment options. Finally, we briefly examine the potential use of artificial intelligence (AI) in the development of new antifungal treatments, diagnoses, and resistance prediction, which provides powerful tools in the fight against fungal pathogens. Overall, we highlight the pressing need for continued research to advance antifungal treatments and improve outcomes for high-risk populations.

A review of the fernane-type triterpenoids as anti-fungal drugs

Human fungal pathogens could cause a broad plethora of infections in both the immunocompetent and immunocompromised host. Fungal infections have become important causes of morbidity and mortality in recent years, the current arsenal of anti-fungal therapies was restricted. Ibrexafungerp was a novel, highly bioavailable glucan synthase inhibitor formulated for both intravenous and oral administration being developed by Scynexis; it was also the first novel anti-fungal drug class approved in more than 20 years. Ibrexafungerp was one semi-synthetic derivative of enfumafungin, a natural product isolated from fungi. This review reported the discovery of enfumafungin and ibrexafungerp, their anti-fungal mechanism, summed up 63 fernane-type triterpenoids from natural products, including 49 from plants, 9 from fungi and 5 from lichen. In addition, the review summarized the progress of enzymes responsible for the biosynthesis of type II fernane triterpenoid (enfumafungin skeleton) and type I fernane triterpenoid (polytolypin skeleton). The good example kept our confidence up for searching for new leading compounds and discovering drugs from fungi.

Fluconazole-Resistant Candida albicans Vaginal Infections at a Referral Center and Treated With Boric Acid

OBJECTIVE

The authors investigate the incidence of clinical and mycological resistance of Candida albicans vulvovaginitis (VVC) at the Jefferson Vulvovaginal Health Center. They also review their experience with boric acid in the treatment of fluconazole-resistant VVC.

METHODS

The authors conducted a retrospective chart review of all patients with C. albicans VVC diagnosed at the Jefferson Vulvovaginal Health Center between November 2019 and December 2021. Patients with clinically defined fluconazole resistance were identified. Information about demographics, in vitro susceptibility testing, and treatment outcomes with boric acid was obtained.

RESULTS

Of 970 patients with vaginal C. albicans isolates, 71 (7.3%) with clinically defined fluconazole-resistant C. albicans infections were identified. Relevant demographics included 45.1% African American, 43.7% aged younger than 30 years, and 43.7% with body mass index less than 25. Of the 71 patients, 58 (81.7%) received vaginal boric acid treatment. The mycological and clinical cure rates were 85.7% and 73.7%, respectively. After successful boric acid treatment and negative yeast cultures, 14.3% of patients had a mycological recurrence within 3 months. Of 31 isolates with antifungal susceptibility testing, 83.9% (26/31) were found to have minimal inhibitory concentration results consistent with fluconazole resistance.

CONCLUSIONS

In a tertiary care vulvovaginal health center, fluconazole-resistant Candida albicans VVC is by no means uncommon and usually responds in the short term to treatment with boric acid. However, in the absence of maintenance boric acid, recurrence of culture-positive VVC is likely.

Oteseconazole: a long-awaited diversification of the antifungal arsenal to manage recurrent vulvovaginal candidiasis (RVVC)

INTRODUCTION

Recurrent vulvovaginal candidiasis (RVVC) affects women worldwide and has far-reaching implications for a patient's quality of life. For decades, maintenance treatment using the azole antifungal fluconazole was the preferred treatment. Although efficient in controlling the symptoms, the development of azole resistance and high rates of recurrence after therapy cessation have emerged as significant limitations. Nevertheless, persistent efforts have delivered novel treatment options. Oteseconazole (VT-1161), marketed as VIVJOA, is an oral, tetrazole antifungal with unprecedented specificity toward the fungal lanosterol 14α-demethylase.

AREAS COVERED

We reviewed literature data on oteseconazole with a focus on the management of RVVC.

EXPERT OPINION

Therapeutic options for RVVC are limited, and novel, innovative approaches are needed to treat this debilitating condition. These therapies need to be well-tolerated and prevent RVVC recurrence. The available clinical data show excellent safety and efficacy, with an unprecedentedly low recurrence rate. However, we believe health-care providers should be mindful to monitor for the development of resistance, as this may result in treatment failure. Further, the availability and cost may, like for most novel drugs, affect the widespread clinical implementation of VIVJOA. Altogether, we are convinced that VIVJOA is a significant advance in RVVC management.

New Antifungals for Vulvovaginal Candidiasis: What Is Their Role?

New antifungals, ibrexafungerp and oteseconazole, are now available for treatment of vulvovaginal candidiasis. Both have novel antimicrobial and pharmacokinetic properties and advantages over fluconazole, although comparative trials have involved only placebo. In the absence of allergy, intolerance, and resistance, it is unclear whether these antifungals will replace fluconazole.

Oral Ibrexafungerp for Vulvovaginal Candidiasis Treatment: An Analysis of VANISH 303 and VANISH 306

Background: Ibrexafungerp is a novel antifungal treatment for acute vulvovaginal candidiasis (VVC). Using pooled data from two phase three studies (VANISH 303 and 306) in the treatment of acute VVC, this analysis sought to determine the effectiveness of ibrexafungerp in various patient subgroups that may impact outcomes. Materials and Methods: Data from VANISH 303 (NCT03734991) and VANISH 306 (NCT03987620) evaluating ibrexafungerp 300 mg twice daily (BID) for 1 day versus placebo, were pooled and analyzed to determine clinical cure rate, clinical improvement, and mycological cure at the test-of-cure visit (day 11 ± 3) and symptom resolution at the follow-up visit (day 25 ± 4) in the overall population. Patient subgroups analyzed included race, body mass index (BMI), baseline vulvovaginal signs and symptoms (VSS) score, and Candida species. Results: At the test-of-cure visit, patients receiving ibrexafungerp, compared with those who received placebo, had significantly higher rates of clinical cure (56.9% [214/376 patients] vs. 35.7% [65/182 patients]), clinical improvement (68.4% [257/376 patients] vs. 45.1% [82/182 patients]), and mycological cure (54.0% [203/376 patients] vs. 24.2% [44/182 patients]; all p < 0.0001). At the follow-up visit, patients receiving ibrexafungerp had sustained responses with higher symptom resolution rates (66.8% [251/376 patients]) versus placebo (48.4% [88/182 patients]; p < 0.0001). Race, BMI, baseline VSS score (including VSS severity score 13-18), and Candida species infection did not adversely affect clinical cure rates. Safety analysis results were consistent with the individual studies. Conclusions: Ibrexafungerp provides a safe and well-tolerated first-in-class fungicidal, 1-day oral treatment for patients with acute VVC, the first new therapy in >20 years. Clinical Trial Registration Number: NCT03734991.

Pathogenesis and virulence of Candida albicans

Candida albicans is a commensal yeast fungus of the human oral, gastrointestinal, and genital mucosal surfaces, and skin. Antibiotic-induced dysbiosis, iatrogenic immunosuppression, and/or medical interventions that impair the integrity of the mucocutaneous barrier and/or perturb protective host defense mechanisms enable C. albicans to become an opportunistic pathogen and cause debilitating mucocutaneous disease and/or life-threatening systemic infections. In this review, we synthesize our current knowledge of the tissue-specific determinants of C. albicans pathogenicity and host immune defense mechanisms.

Ibrexafungerp: A new triterpenoid antifungal

DISCLAIMER

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

The pharmacology, microbiology, pharmacokinetics, pharmacodynamics, efficacy, safety, and role of ibrexafungerp in the treatment of fungal infections are reviewed.

SUMMARY

Ibrexafungerp is the first triterpenoid antifungal. Similarly to echinocandins, it inhibits the synthesis of 1,3-β-d-glucan. However, it binds to a different site on the enzyme than echinocandins, resulting in limited cross-resistance. Ibrexafungerp exerts concentration-dependent fungicidal activity against Candida species and retains in vitro activity against most fluconazole-resistant strains. It is also active against Aspergillus species. Ibrexafungerp has been shown to be safe and effective in the treatment of vulvovaginal candidiasis caused by Candida albicans in phase 2 and phase 3 clinical trials. It is approved for vulvovaginal candidiasis in adult and postmenarchal pediatric females and is given as two 150-mg tablets orally, administered 12 hours apart. Ibrexafungerp is contraindicated in pregnancy. The most commonly reported adverse reactions were diarrhea, nausea, abdominal pain, dizziness, and vomiting. Ibrexafungerp should be avoided with strong or moderate CYP3A inducers, and the dose should be reduced with strong CYP3A inhibitors. Ibrexafungerp may be useful for patients who are not able to receive fluconazole or prefer oral therapy for the treatment of vulvovaginal candidiasis. However, it is more expensive than the 150-mg tablet of generic fluconazole, which is the current standard of care for vulvovaginal candidiasis. Clinical trials are ongoing for recurrent and complicated vulvovaginal candidiasis as well as invasive candidiasis and pulmonary aspergillosis.

CONCLUSION

Ibrexafungerp is an alternative to fluconazole for the treatment of vulvovaginal candidiasis in nonpregnant females. It has the potential to be useful for recurrent and complicated vulvovaginal candidiasis as well as certain invasive fungal infections.

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.

Antifungal Susceptibility Testing: A Primer for Clinicians

Clinicians treating patients with fungal infections may turn to susceptibility testing to obtain information regarding the activity of different antifungals against a specific fungus that has been cultured. These results may then be used to make decisions regarding a patient's therapy. However, for many fungal species that are capable of causing invasive infections, clinical breakpoints have not been established. Thus, interpretations of susceptible or resistant cannot be provided by clinical laboratories, and this is especially true for many molds capable of causing severe mycoses. The purpose of this review is to provide an overview of susceptibility testing for clinicians, including the methods used to perform these assays, their limitations, how clinical breakpoints are established, and how the results may be put into context in the absence of interpretive criteria. Examples of when susceptibility testing is not warranted are also provided.

Efficacy and safety of oral ibrexafungerp for the treatment of acute vulvovaginal candidiasis: a global phase 3, randomised, placebo-controlled superiority study (VANISH 306)

Objective

To evaluate the efficacy and safety of ibrexafungerp versus placebo for acute vulvovaginal candidiasis (VVC) treatment.

Design

Global phase 3, randomised, placebo‐controlled superiority study.

Setting

Study sites in the USA (n = 19) and Bulgaria (n = 18).

Population

Female patients aged ≥12 years with acute VVC and a vulvovaginal signs and symptoms (VSS) score ≥4 at baseline.

Methods

Patients were randomly assigned 2:1 to ibrexafungerp (300 mg twice for 1 day) or placebo.

Main outcome measures

The primary endpoint was the percentage of patients with a clinical cure (VSS = 0) at the test‐of‐cure visit (day 11 ± 3). Secondary endpoints included percentages of patients with mycological eradication, clinical cure and mycological eradication (overall success), clinical improvement (VSS ≤1) at test‐of‐cure visit, and complete resolution of symptoms at follow‐up visit (day 25 ± 4).

Results

At the test‐of‐cure visit, patients receiving ibrexafungerp had significantly higher rates of clinical cure (63.3% [119/188] versus 44.0% [37/84]; P = 0.007), mycological eradication (58.5% [110/188] versus 29.8% [25/84]; P < 0.001), overall success (46.1% [82/188] versus 28.4% [23/84]; P = 0.022) and clinical improvement (72.3% [136/188] versus 54.8% [46/84]; P = 0.01) versus those receiving placebo. Symptom resolution was sustained and further increased with ibrexafungerp (73.9%) versus placebo (52.4%) at follow‐up (P = 0.001). Ibrexafungerp was generally well tolerated. Adverse events were primarily gastrointestinal and were mild to moderate in severity.

Conclusions

Ibrexafungerp demonstrated statistical superiority over placebo for the primary and secondary endpoints. Ibrexafungerp is a promising novel, well‐tolerated and effective oral 1‐day treatment for acute VVC.

Tweetable abstract

Ibrexafungerp is statistically superior to placebo for the treatment of vulvovaginal candidiasis.

Ibrexafungerp is statistically superior to placebo for the treatment of vulvovaginal candidiasis.

Linked article This article is commented on by KSJ Olah, p. 421–422 in this issue. To view this mini commentary visit https://doi.org/10.1111/1471-0528.17000.

Ibrexafungerp versus placebo for vulvovaginal candidiasis treatment: a phase 3, randomized, controlled superiority trial (VANISH 303)

Background

Current treatment of vulvovaginal candidiasis (VVC) is largely limited to azole therapy. Ibrexafungerp is a first-in-class triterpenoid antifungal with broad-spectrum anti-Candida fungicidal activity. The objective of this study was to evaluate the efficacy and safety of ibrexafungerp compared with placebo in patients with acute VVC.

Methods

Patients were randomly assigned 2:1 to receive ibrexafungerp (300 mg twice for 1 day) or placebo. The primary endpoint was the percentage of patients with a clinical cure (complete resolution of vulvovaginal signs and symptoms [VSS] = 0) at test-of-cure (day 11 ± 3). Secondary endpoints included the percentage of patients with mycological eradication, overall success (clinical cure and mycological eradication), clinical improvement (VSS ≤ 1) at test-of-cure, and symptom resolution at follow-up (day 25 ± 4).

Results

Patients receiving ibrexafungerp had significantly higher rates of clinical cure (50.5% [95/188] vs 28.6% [28/98]; P = .001), mycological eradication (49.5% [93/188] vs 19.4% [19/98]; P < .001), and overall success (36.0% [64/178] vs 12.6% [12/95]; P < .001) compared with placebo. Symptom resolution was sustained and further increased with ibrexafungerp compared with placebo (59.6% [112/188] vs 44.9% [44/98]; P = .009) at follow-up. Post hoc analysis showed similar rates of clinical cure and clinical improvement at test-of-cure for Black patients (54.8% [40/73] and 63.4% [47/73], respectively) and patients with a body mass index >35 (54.5% [24/44] and 68.2% [30/44], respectively) compared with overall rates. Ibrexafungerp was well tolerated. Adverse events were primarily gastrointestinal and mild in severity.

Conclusions

Ibrexafungerp provides a promising safe and efficacious oral treatment that mechanistically differs from current azole treatment options for acute VVC.

Ibrexafungerp: First Approval

Ibrexafungerp (BREXAFEMME®) is an orally active triterpenoid antifungal drug being developed by SCYNEXIS, Inc. for the treatment of fungal infections. The inhibition of β-1,3-D glucan synthetase by ibrexafungerp compromises the integrity of fungal cell walls. Ibrexafungerp has been recently approved for the treatment of vulvovaginal candidiasis (VVC), and it is the first novel antifungal drug class to be approved in more than 20 years. Development for the treatment of recurrent VVC and invasive fungal infections is ongoing. This article summarizes the milestones in the development of ibrexafungerp leading to this first approval for the treatment of VVC in adult and postmenarchal paediatric females.