Efinaconazole in the treatment of onychomycosis

Efinaconazole 10% solution: a comprehensive review of its use in the treatment of onychomycosis

INTRODUCTION

Onychomycosis is an infection of the nail bed and the nail plate. While oral antifungals are first-line for moderate-to-severe onychomycosis, topical efinaconazole 10% solution (JUBLIA®; Clenafin®) is effective and safe for mild-to-moderate severity onychomycosis. It is FDA-approved for patients aged 6 years and above.

AREAS COVERED

This literature review includes pharmacokinetics, microbiology, efficacy, safety, and post-marketing surveillance. It demonstrates consistent safety and efficacy across diverse patient demographics and comorbidities, including pediatric, diabetic and the elderly populations, without systemic side effects or drug interactions.

EXPERT OPINION

Efinaconazole 10% solution is an important addition to the armamentarium of therapies available to treat onychomycosis. Certain subgroups respond particularly well: females versus males, children versus adults, early onset onychomycosis (<1-year disease), those with mild onychomycosis (≤25% nail involvement), absence of tinea pedis, and thin nail plates at baseline (<1 mm thickness). Efinaconazole 10% solution is effective in diabetics and has demonstrated efficacy against dermatophytomas. Efinaconazole may be a consideration when terbinafine resistance is a concern, due to its different target of action.

Impact of new antifungal medications on onychomycosis prescriptions and costs in Japan: A nationwide claims database study

Onychomycosis, a fungal nail infection, is a common dermatological condition in Japan, with a prevalence of approximately 5%-10%. Despite the introduction of new antifungal medications and updated treatment guidelines published in 2019, data on real-world prescription trends and the associated medical costs are limited. This study aimed to investigate the prescription patterns and medical costs of topical and oral antifungal medications for onychomycosis in Japan from fiscal years 2014 to 2021 using the National Database of Health Insurance Claims and Specific Health Checkups of Japan Open Data. We analyzed the annual prescription volumes and medical costs of four antifungal medications: efinaconazole, luliconazole, fosravuconazole, and terbinafine. The prescription volume of efinaconazole, a topical medication launched in 2014, rapidly increased and dominated the market share. Fosravuconazole, an oral medication introduced in 2018, showed an increasing trend, coinciding with a decline in efinaconazole prescriptions. Terbinafine, a well-established oral medication, experienced a substantial decrease in prescription volume. The sex- and age-adjusted prescription volume per 100 000 population was higher among older adults, particularly for efinaconazole. The total medical costs for onychomycosis treatment more than doubled in fiscal year 2015 compared with that for 2014, mainly driven by efinaconazole prescriptions, and exceeded 30 billion Japanese yen in fiscal years 2019-2021. The costs slightly decreased in fiscal years 2020 and 2021, possibly due to the introduction of fosravuconazole. The predominance of topical prescriptions, especially in older adults, raises concerns regarding adherence to the Japanese guidelines that recommend oral antifungals as the first-line treatment for onychomycosis. The substantial increase in medical costs also highlights the economic burden of onychomycosis and the need for cost-effective treatment strategies. This study provides valuable insights into the real-world prescription trends and medical costs of onychomycosis treatment in Japan, suggesting an opportunity to assess potential gaps between guideline recommendations and clinical practice.

Antifungal Selection for the Treatment of Onychomycosis: Patient Considerations and Outcomes

Onychomycosis, a common fungal nail infection, affects >20% of adults over age 60 and >50% of people over age 70. Onychomycosis may cause pain, psychosocial problems, and secondary infections, therefore meriting treatment. This review describes the range of treatment modalities, including FDA-approved systemic drugs and topical therapies. Additionally, new and emerging oral and topical therapies are discussed. We emphasize the importance of tailoring onychomycosis therapy to individual patient characteristics, comorbidities, preferences, extent of nail involvement, and fungal species, such that physicians may optimize treatment outcomes, patient satisfaction, and safety.

A Chemo-Enzymatic Approach for Preparing Efinaconazole with High Optical Yield

Herein, we present a novel and ecofriendly biocatalytic approach for synthesizing efinaconazole (7), a clinically used antifungal agent. This method involves utilizing benzaldehyde lyase (BAL) to catalyze the crucial benzoin condensation step in the ketone precursor. Treating 2,4-difluorobenzaldehyde with BAL in the presence of thiamin-diphosphate (ThDP) and Mg2+ resulted in the formation of α-hydroxy ketone which then underwent the preparation of 7. This innovative approach not only provides a greener alternative but also offers significant advantages over the traditional chemical process. Through our efforts and development work, we have established efficient and scalable procedures that enable the production of 7 in a moderate 38% yield.

Formulation-by-Design of Efinaconazole Spanlastic Nanovesicles for Transungual Delivery Using Statistical Risk Management and Multivariate Analytical Techniques

As regulatory and technical landscapes for pharmaceutical formulation development are rapidly evolving, a risk-management approach using multivariate analysis is highly essential for designing a product with requisite critical quality attributes (CQA). Efinaconazole, a newly approved poorly water-soluble antifungal triazole drug has poor permeability. Spanlastics, new-generation surfactant nanovesicles, being fluidic, help improve the permeability of drugs. Therefore, we optimized efinaconazole spanlastics using the concepts of Formulation-by-Design (FbD) and explored the feasibility of transungual delivery for the management of onychomycosis. Using the Ishikawa fishbone diagram, the risk factors that may have an impact on the CQA of efinaconazole spanlastic vesicles were identified. Application of the Plackett–Burman experimental design facilitated the screening of eight different formulation and process parameters influencing particle size, transmittance, relative deformability, zeta potential, entrapment efficiency, and dissolution efficiency. With the help of Pareto charts, the three most significant factors were identified, viz., vesicle builder (Span), edge activator (Tween), and mixing time. The levels of these three critical variables were optimized by FbD to reduce the particle size and maximize the transparency, relative deformability, encapsulation efficiency, and dissolution efficiency of efinaconazole spanlastic nanovesicles. Bayesian and Lenth’s analysis and mathematical modeling of the experimental data helped to quantify the critical formulation attributes required for getting the formulation with optimum quality features. The optimized efinaconazole-loaded spanlastic vesicles had a particle size of 197 nm, transparency of 91%, relative deformability of 12.5 min, and dissolution efficiency of 81.23%. The spanlastic formulation was incorporated into a gel and explored ex vivo for transungual delivery. This explorative study provides an example of the application of principles of risk management, statistical multivariate analysis, and the FbD approach in developing efinaconazole spanlastic nanovesicles.

Efinaconazole topical solution (10%) for the treatment of onychomycosis in adult and pediatric patients

Introduction: Onychomycosis, a common nail disorder caused by fungal infection, can be managed pharmaceutically with oral or topical treatments. While oral treatments are often used first-line to treat nail infections, these systemic antifungals are not appropriate for all patients, and no oral treatments are approved for use in children in the USA. Given this need, topical antifungals were developed, which can be used as monotherapy or in combination with oral drugs.Areas Covered: Efinaconazole 10% solution is an azole antifungal indicated for topical treatment of toenail onychomycosis in pediatric and adult patients. This qualitative literature review summarizes available chemical, pharmacological, efficacy, safety, and post-marketing surveillance data of efinaconazole 10% topical solution. Efinaconazole 10% has been shown to be safe and efficacious regardless of disease severity/duration at baseline; patient gender, ethnicity, or age (including pediatrics); or comorbidities such as diabetes or tinea pedis. Overall, efinaconazole is a safe and effective clinical option for the treatment and management of onychomycosis.Expert Opinion: Efinaconazole is the first new antifungal approved for onychomycosis in 10 years in the USA. It has comparable efficacy to systemic antifungal agents such as itraconazole, and a favorable adverse events profile with minimal systemic exposure and no drug-drug interactions.

Chemistry and Pharmacology of Luliconazole (Imidazole Derivative): A Novel Bioactive Compound to Treat Fungal Infection-A Mini Review

Background:

Currently, ringworm treatment drugs include two major categories: first, propylene amine drugs, such as terbinafine, butenafine and naftifine, which exert their bactericidal effects through inhibiting squalene cyclase, causing the lack of ergosterol and accumulation of squalene. The second category of imidazole drugs includes miconazole, econazole, clotrimazole, ketoconazole and bifonazole.

Mechanism:

These synthetic antifungal agents exhibits their action by inhibiting the lanosterol 14α- demethylation activity of fungal cell, leading to the prevention of the ergosterol synthesis of cell membrane, changing the cell membrane permeability, and resulting in the loss of important intracellular fungal material and causing fungal death.

Applications:

At present, Imidazole antifungal agents are commonly used drugs in clinical treatment of ringworm with extensive clinical applications.

Conclusion:

The present review covers the chemistry and detailed pharmacology aspects of luliconazole.

Preparation and in vivo evaluation of a highly skin- and nail-permeable efinaconazole topical formulation for enhanced treatment of onychomycosis

Onychomycosis is a progressive fungal infection of the nails that involves the deeper nail layer and nail bed. It is important to maintain sufficient drug concentration in the diseased tissues after topical application. In this study, a stable topical delivery system for efinaconazole (EFN) was designed to enhance absorption potential through the skin and nail plate by incorporating ethanol, diethylene glycol monoethyl ether (Transcutol P) and isopropyl myristate, and cyclomethicone into the topical solution as a delivery vehicle, permeation enhancers, and a wetting agent, respectively. In addition, the stability of EFN in the formulation was significantly improved by adding butylated hydroxytoluene, diethylenetriamine pentaacetic acid, and citric acid as an antioxidant, chelating agent, and pH-adjusting agent, respectively, without discoloration. The optimum EFN formulation (EFN-K) showed 1.46-fold greater human skin permeation than that of the reference control (commercial 10% EFN topical solution). Furthermore, after a 24-hour incubation, the amount of infiltrated EFN from EFN-K in the human nail plate was 4.11-fold greater than that of the reference control, resulting in an 89.7% increase in nail flux at 7 days after treatment. EFN-K significantly accelerated structural recovery of the keratin layer in a Trichophyton mentagrophytes-infected guinea pig onychomycosis model, decreasing the mean viable fungal cell count by 54.3% compared to the vehicle-treated group after once-daily treatment for 4 weeks. Thus, the accelerated skin and nail penetration effect of EFN-K is expected to achieve good patient compliance, and improve the complete cure rate of onychomycosis.

Emerging drugs for the treatment of onychomycosis

Introduction: Onychomycosis is a widespread nail disease, often occurring on the feet. It is a chronic and often recurring disease, which makes it difficult to eradicate. The infection may be caused by dermatophytes, non-dermatophyte molds, and yeasts. Traditionally, systemic antifungal medications have been used to treat this infection, but in recent years topical formulations have been the focus of research.Areas covered: This review outlines the current antifungal market and novel treatments currently in development or in experimental phases. It highlights a shift from systemic treatments to topical options as well as penetration enhancers. There are also several novel systemic options in development.Expert opinion: Although there have been significant developments in treatment options for onychomycosis, it remains a challenging chronic condition with less than desirable cure rates. This may be attributed to the formation of fungal biofilms and limited understanding of the fungal lifecycle. However, when patients adhere to treatment protocols and employ preventative measures, outcomes are generally favorable.

ONYCHOMYCOSIS: A Review of New and Emerging Topical and Device-based Treatments

Onychomycosis is a challenging nail condition to treat. The gold standard treatment relies on long-term systemic therapy, which carries risks of potential side effects and drug interactions. Topical alternatives exist; however, treatment outcomes remain disappointing. In this article, we review newer topical formulations that are approved by the United States Food and Drug Administration, as well as other topical drugs that are still undergoing clinical trials. Lasers and energy-based devices have also been used for the treatment of onychomycosis; however, standardized parameters and clear treatment endpoints have yet to be specified. Currently, device-based therapies are considered as options for improving the cosmetic appearance of nails. The use of lasers to improve the penetration of topical antifungal treatments as possible combination treatments is also reviewed.

Low In Vitro Antifungal Activity of Tavaborole against Yeasts and Molds from Onychomycosis

The in vitro activity of tavaborole, an FDA-approved antifungal drug, was compared to that of four antifungal agents against 170 clinical fungal isolates originating from patients with onychomycosis. Tavaborole had low activity against all isolates compared to itraconazole, terbinafine, and fluconazole, the principal choices for treatment of onychomycosis. Thus, it appears that tavaborole is not a candidate for the treatment of onychomycosis due to Candida species, Aspergillus species, and dermatophytes.

Blad-containing oligomer: a novel fungicide used in crop protection as an alternative treatment for tinea pedis and tinea versicolor

PURPOSE

The lack of novel antifungal drugs and the increasing incidence and severity of fungal infections are major concerns worldwide. Herein, we tested the activity of the Blad-containing oligomer (BCO), a new antifungal molecule already in use for agriculture, on Malassezia spp. and dermatophytes, the causal agents of human tinea versicolor and tinea pedis. Given the lack of a standard method for Malassezia susceptibility testing and the plethora of published methods, we also developed an improved method for this genus.

METHODOLOGY

The efficacy of BCO was assessed in vitro and compared to that of the drugs currently utilized in the treatment of tinea versicolor (fluconazole and itraconazole) and tinea pedis (itraconazole and terbinafine). For dermatophytes, the standard microdilution broth-based method was used, with small adjustments, and several broth formulations and inocula sizes were tested to develop an improved susceptibility method for Malassezia spp.

RESULTS

We successfully developed a microdilution broth-based method with considerable advantages over other available methods, and used it for all in vitro susceptibility tests of Malassezia spp. isolates. We report that, on a molar basis, BCO was more effective than fluconazole or itraconazole on most strains of Malassezia spp. isolated from clinical samples (n=29). By contrast, BCO was less effective than itraconazole or terbinafine on the common dermatophytes Trichophyton rubrum and Trichophyton interdigitale.

CONCLUSION

These data place BCO as a promising drug for the treatment of Malassezia-associated skin diseases. Further in vivo studies are now required to ascertain its applicability in the clinical setting.

An invertebrate infection model for evaluating anti-fungal agents against dermatophytosis

Animal models of pathogenic infection are needed to evaluate candidate compounds for the development of anti-infectious drugs. Dermatophytes are pathogenic fungi that cause several infectious diseases. We established a silkworm dermatophyte infection model to evaluate anti-fungal drugs. Injection of conidia of the dermatophyte Arthroderma vanbreuseghemii into silkworms was lethal. A. vanbreuseghemii conidia germinated in liquid culture were more potent against silkworms than non-germinated conidia. Germinated conidia of other dermatophytes, Arthroderma benhamiae, Trichophyton rubrum, and Microsporum canis, also killed silkworms. Injection of heat-treated germinated A. vanbreuseghemii conidia did not kill silkworms, suggesting that only viable fungi are virulent. Injecting terbinafine or itraconazole, oral drugs used clinically to treat dermatophytosis, into the silkworm midgut had therapeutic effects against infection with germinated A. vanbreuseghemii conidia. When silkworms were injected with A. vanbreuseghemii expressing enhanced green fluorescent protein (eGFP), mycelial growth of the fungus was observed in the fat body and midgut. Injection of terbinafine into the silkworm midgut, which corresponds to oral administration in humans, inhibited the growth of A. vanbreuseghemii expressing eGFP in the fat body. These findings suggest that the silkworm infection model with eGFP-expressing dermatophytes is useful for evaluating the therapeutic activity of orally administered anti-fungal agents against dermatophytes.

An Assessment of In Vitro Antifungal Activities of Efinaconazole and Itraconazole against Common Non-Dermatophyte Fungi Causing Onychomycosis

Onychomycosis is a fungal nail infection which is relatively common and difficult to treat. Treatment modalities include nail avulsion, surgical debridement and combination therapy with oral and topical antifungal drugs. In spite of a host of available drugs, clinical cure rates remain discouraging. Drug toxicities, prolonged regimens, lack of patient compliance, and high keratin affinity of drugs are all contributive factors. Efinaconazole is a novel topical triazole antifungal agent that has shown excellent in vitro activity against both dermatophyte and non-dermatophyte fungi causing onychomycosis. This study presents the in vitro susceptibility profiles of 44 common non-dermatophyte fungi against efinaconazole and itraconazole, another azole drug used in the treatment of onychomycosis.

Efficacy Coefficients Determined Using Nail Permeability and Antifungal Activity in Keratin-Containing Media Are Useful for Predicting Clinical Efficacies of Topical Drugs for Onychomycosis

Onychomycosis is difficult to treat topically due to the deep location of the infection under the densely keratinized nail plate. In order to obtain an in vitro index that is relevant to the clinical efficacy of topical anti-onychomycosis drugs, we profiled five topical drugs: amorolfine, ciclopirox, efinaconazole, luliconazole, and terbinafine, for their nail permeabilities, keratin affinities, and anti-dermatophytic activities in the presence of keratin. Efinaconazole and ciclopirox permeated full-thickness human nails more deeply than luliconazole. Amorolfine and terbinafine did not show any detectable permeation. The free-drug concentration of efinaconazole in a 5% human nail keratin suspension was 24.9%, which was significantly higher than those of the other drugs (1.1-3.9%). Additionally, efinaconazole was released from human nail keratin at a greater proportion than the other drugs. The MICs of the five drugs for Trichophyton rubrum were determined at various concentrations of keratin (0-20%) in RPMI 1640 medium. The MICs of ciclopirox were not affected by keratin, whereas those of efinaconazole were slightly increased and those of luliconazole and terbinafine were markedly increased in the presence of 20% keratin. Efficacy coefficients were calculated using the nail permeation flux and MIC in media without or with keratin. Efinaconazole showed the highest efficacy coefficient, which was determined using MIC in media with keratin. The order of efficacy coefficients determined using MIC in keratin-containing media rather than keratin-free media was consistent with that of complete cure rates in previously reported clinical trials. The present study revealed that efficacy coefficients determined using MIC in keratin-containing media are useful for predicting the clinical efficacies of topical drugs. In order to be more effective, topical drugs have to possess higher efficacy coefficients.

Successful Treatment of Paecilomyces lilacinus Onychomycosis with Efinaconazole and Tavaborole

Paecilomyces lilacinus, also known as Purpureocillium lilacinum, is a non-dermatophyte mold found in the soil and used as nematocide for crops. P. lilacinus can cause rare opportunistic infections in humans ranging from endocarditis, keratitis, to onychomycosis with significant resistance to conventional antifungals. There are only two cases of onychomycosis caused by P. lilacinus reported in the literature and none that were successfully treated. Here we present a case of successfully treated onychomycosis caused by P. lilacinus with efinaconazole and tavaborole in a patient who had failed treatment with oral fluconazole, itraconazole, terbinafine, and topical ciclopirox and naftifine.