Efficacy and safety of bifonazole urea in the two-phase treatment of onychomycosis

Race reporting and representation in onychomycosis clinical trials: A systematic review

BACKGROUND

Onychomycosis is the most common nail disease seen in clinical practice. Inclusion of diverse groups in onychomycosis clinical trials subjects is necessary to generalise efficacy data.

OBJECTIVES

We aimed to systematically review race and ethnicity reporting and representation, as well as, treatment outcomes in onychomycosis clinical trials.

METHODS

A PubMed search for onychomycosis clinical trials was performed in August 2020. Primary clinical trial data were included and post hoc analyses were excluded. Categorical variables were compared using chi-squared and Fisher's exact tests. Statistical significance was set at p < .05. Photos in articles were categorised by Fitzpatrick skin type.

RESULTS

Only 32/182 (17.5%) trials reported on race and/or ethnicity and only one trial compared treatment efficacy in different subgroups. Darker skin colours were infrequently depicted in articles. Topical treatment, location with ≥1 US-based site, industry funding type and publication date after 2000 were significantly associated with reporting of racial/ethnic data (p < .05 for all comparisons).

LIMITATIONS

Demographics on excluded subjects and methods of recruitment were not available. Assigning Fitzpatrick skin type is inherently subjective.

CONCLUSIONS

This study highlights a need for consistent reporting of races and ethnicities of onychomycosis clinical trial participants with subgroup analyses of treatment efficacies.

The use of urea for the treatment of onychomycosis: a systematic review

Background

Onychomycosis, a fungal infection affecting the nail plate, is a common condition often requiring prolonged treatment regimens, with low success rates. Urea is one treatment option, which is thought to improve the efficacy of topical and oral antifungal agents. Despite a theoretical basis for the use of urea for the treatment of onychomycosis, the evidence-base for this treatment has not been systematically reviewed.

Aim

The purpose of this study was to conduct a systematic literature review to determine the efficacy and safety of urea as a monotherapy and as adjunct therapy, compared to other treatment regimens for onychomycosis.

Method

A systematic literature search of ten electronic databases was conducted. Only studies that used microscopy and culture or other validated laboratory-based testing method to confirm the presence of a fungal infection before treatment were included. The outcome measures assessed were efficacy (defined in terms of mycological, clinical and complete cure) and safety (defined as self-reported adverse events).

Results

The systematic search yielded 560 unique studies for review. Of these, only six were eligible for inclusion. All studies were observed to have methodological concerns, most studies consisted of small sample sizes and were difficult to compare given heterogeneity in outcome measures and follow-up time. Despite this, a trend was observed to suggest that urea, when added to topical or oral antifungal treatment regimens, improved efficacy of the treatment.

Conclusion

This review suggests that topical urea, as an adjunct to topical and oral antifungal treatment regimens, may improve the efficacy of treatment. However, further research is needed.

Electronic supplementary material

The online version of this article (10.1186/s13047-019-0332-3) contains supplementary material, which is available to authorized users.

An update on treatment of onychomycosis

Onychomycosis (OM) is a fungal infection of the nail plate or nail bed which is highly prevalent in the general population and also responsible for significant morbidity. The condition needs to be treated in view of the physical and emotional handicap it produces. The peculiarities of the nail apparatus in health and disease lead to difficulties in being able to successfully treat this condition. Hence, the very same antifungals which produce high cure rates in skin infections are rendered less efficacious in nail disease. Low cure rates and high relapse rates even with highly efficacious antifungals have lead to an increasing interest in exploring newer treatment options which can ensure drug penetration, drug persistence, mycological cure and effective prevention of relapse. The current review aims to summarize our current status of knowledge about the treatment options for OM. It also summarizes the newer areas of research especially with respect to devices related therapies; physical measures to enhance penetration through nail; and development and evaluation of synergistic combinations.

Toenail onychomycosis: current and future treatment options

Onychomycosis is a common disease affecting as much as 8% of the general population. Treatment of onychomycosis is challenging, complicated by low cure rates and relatively high relapse rates. This paper reviews the efficacy of current oral, topical, and surgical treatment options. Currently, the treatment of choice for toenail onychomycosis is oral terbinafine because of its high efficacy, low relapse rates, and cost-effectiveness. Oral itraconazole or fluconazole could be considered for infections caused by Candida. Topical therapies may be a useful adjunct to these systemic therapies, but are less effective when used alone. More research is needed to determine the best measures for preventing reinfection.

Topical antifungal drugs for the treatment of onychomycosis: an overview of current strategies for monotherapy and combination therapy

BACKGROUND

Onychomycosis is a relatively common disease accounting for up to 50% of all nail disorders and its prevalence rises with age. As onychomycosis is an important medical disorder affecting both patient's health and quality of life, it requires prompt and effective treatment.

OBJECTIVE

Topical antifungal nail lacquers have been formulated to provide efficient delivery to the nail unit. As both amorolfine and ciclopirox have proved useful as monotherapy for onychomycosis that does not involve the nail matrix area, the purpose of this article is to check if, when combined with oral agents, the effectiveness and scope of treatment can be improved further.

METHODS

Combining data for mycological cure with clinical success (nail morphology) provides a more exacting efficacy measure.

RESULTS

Clinical investigations have shown that the combination of oral therapies with antifungal nail lacquer can confer considerable advantage over monotherapy with either drug type.

CONCLUSION

The improved effectiveness and economic advantages of combined topical/oral therapies benefit both patients and health providers; these treatment regimens therefore have an important role to play in the modern management of onychomycosis.

Management of onychomycosis with topicals

Of all superficial fungal infections, onychomycosis is the most difficult to manage. Practitioners of all disciplines realize its chronic nature, difficulty in eradication, and propensity to recur. Topical treatment of onychomycosis, as opposed to oral therapies, offers a distinct advantage by allowing the patient to apply medication directly to the affected area, thus decreasing the potential for serious adverse events, such as drug toxicity and drug interactions. In the past, a multitude of topical antifungal agents were used in the treatment of onychomycosis; however, an acceptable level of scientific evidence regarding their effectiveness was lacking and this was evident by poor success rates. The development of a comparatively effective topical agent, the only one so far to gain FDA approval, has renewed interest in this form of therapy. Improved versions are being developed that may overcome the shortcomings of the first approved topical agent.

The use of topical therapies to treat onychomycosis

The management of onychomycosis using topical agents has improved with the introduction of ciclopirox and amorolfine nail lacquers; other topical agents may be less effective. The combination of a nail lacquer with an oral antifungal agent may further improve efficacy rates in certain clinical presentations (eg, among those individuals with severe onychomycosis). Topical agents have a favorable adverse events profile. Further studies are required on the treatment of onychomycosis with nail lacquers.

Pharmacokinetics of antifungal agents in onychomycoses

Onychomycosis is caused by infection by fungi, mainly dermatophytes and nondermatophyte yeasts or moulds; it affects the fingernails and, more frequently, the toenails. Dermatophytes are responsible for about 90 to 95% of fungal infections. Trichophyton rubrum is the most common dermatophyte; Candida albicans is the major nondermatophyte yeast. Although topical therapy of onchomycosis does not lead to systemic adverse effects or interactions with concomitantly taken drugs, it does not provide high cure rates and requires complete compliance from the patient. At present there are 3 oral antifungal medications that are generally used for the short term treatment of onychomycosis: itraconazole, terbinafine and fluconazole. The persistence of these active drugs in nails allows weekly administration, reduced treatment or a pulse regimen. Good clinical and mycological efficacies are obtained with itraconazole 100 to 200 mg daily, terbinafine 250mg daily for 3 months, or fluconazole 150 mg weekly for at least 6 months. Itraconazole is a synthetic triazole with a broad spectrum of action. It is well absorbed when administered orally and can be detected in nails 1 to 2 weeks after the start of therapy. The nail : plasma ratio stabilises at around 1 by week 18 of treatment. Itraconazole is still detectable in nails 27 weeks after stopping administration. Nail concentrations are higher than the minimum inhibitory concentration (MIC) for most dermatophytes and Candida species from the first month of treatment. The elimination half-life of itraconazole from nails is long, ranging from 32 to 147 days. Terbinafine is a synthetic allylamine that is effective against dermatophytes. Terbinafine is well absorbed from the gastrointestinal tract, and the time to reach effective concentrations in nail is 1 to 2 weeks. The half-life is from 24 to 156 days, explaining the observed persistence of terbinafine in nails for longer than 252 days. Fluconazole is a bis-triazole broad spectrum antifungal with high oral bioavailability. The uptake of fluconazole by nail increases with the length of treatment, and nail : plasma ratios are generally 1.5 to 2 at steady state. Fluconazole concentrations exceed the MIC for Candida species soon after the start of treatment. Fluconazole concentrations fall slowly after the drug is stopped, with a half-life of 50 to 87 days, and fluconazole is still detectable in nails 5 months after the end of treatment. All these drugs are potent inhibitors of cytochrome P450 (CYP) enzymes and may increase the plasma concentrations of concomitantly used drugs. Itraconazole inhibits CYP3A4. Fluconazole inhibits CYP3A4, but to a lesser degree than itraconazole, CYP2C9 and CYP2C19. Terbinafine inhibits CYP2D6.

Onychomycosis in children: treatment with bifonazole-urea

We assessed the safety and efficacy of a two-phase topical treatment with bifonazole-urea ointment in children with onychomycosis. Twenty-five children younger than 16 years old with proved onychomycosis were included in the study. Bifonazole-urea ointment was administered under occlusion until the nontraumatic removal of the nail was achieved. Bifonazole cream was then applied for 4 weeks and a follow-up visit 4 weeks after cessation of medication was scheduled. During the study, periodic clinical and mycologic evaluations were carried out. Of the 25 patients included, 17 were cured (68%), 6 improved, and 2 failed treatment. The main etiologic agent isolated was Trichophyton rubrum (92%). Two patients had minor side effects, both during the occlusive phase, one each with mild pain and a probable dermatitis from the adhesive strips. Treatment was not discontinued in both of these cases. We concluded that a two-phase treatment with bifonazole-urea is effective and safe, and represents a new therapeutic choice for onychomycosis in children.