A multicentre, randomised, parallel-group, double-blind, vehicle-controlled and open label versus amorolfine 5% study, to evaluate the efficacy and safety of terbinafine 10% nail lacquer in the treatment of onychomycosis

Efficacy of Fractional Versus Fully Ablative CO2 Laser for Distolateral Onychomycosis: Experience With 20 Patients

INTRODUCTION

Oral antifungals are the treatment choice for onychomycosis, and topical therapies are favored in cases of limited nail involvement. Recently, carbon dioxide (CO2) laser treatment has emerged as an option to enhance the effectiveness of topical therapies.

OBJECTIVES

Our objective was to compare the efficacy of fractional ablative and fully ablative CO2 laser treatments for distolateral subungual onychomycosis affecting a single toenail and caused by dermatophytes.

METHODS

The records of 10 patients treated with a single fully ablative CO2 session were matched with those of 10 patients who underwent a single CO2 fractional treatment. All had previously failed topical antifungal lacquers and were discharged with the prescription of topical ciclopirox nail lacquer (8%) for 3 months.

RESULTS

The clinical response rates were 80% for the fully ablative group and 60% for the fractional group. Additionally, the mean reduction in Onychomycosis Severity Index from baseline to 8.6±1.6 weeks after treatment completion was 6.9±5.4 in the fully ablative group and 3.6±6.6 in the fractional group. The relapse rate among responders was 12.5% in the fully ablative and 33.3% in the fractional group after a mean follow-up time of 29.4±2.3 weeks.

CONCLUSIONS

Fractional and fully ablative CO2 laser in combination with ciclopirox lacquer could increase the response rate in onychomycosis resistant to topical antifungals when systemic therapy is contraindicated or not yet pursued. Fully ablative mode therapy is significantly more effective than fractional (P < 0.05). Further studies are needed to identify prognostic response factors and assess the long-term effectiveness of CO2 laser treatment.

Penetration Profile of Terbinafine Compared to Amorolfine in Mycotic Human Toenails Quantified by Matrix-Assisted Laser Desorption Ionization-Fourier Transform Ion Cyclotron Resonance Imaging

INTRODUCTION

Amorolfine 5% lacquer is an established topical treatment for fungal infection of the nails. The success of topical therapy for onychomycosis depends on whether the permeated drug concentration in the deep nail bed is retained above the effective antifungal minimum inhibitory concentration (MIC). We compared the penetration profile of amorolfine and a new topical formula of terbinafine in human mycotic toenails using matrix-assisted laser desorption ionization mass spectrometry imaging-Fourier transform ion cyclotron resonance (MALDI-FTICR) imaging.

METHODS

Amorolfine 5% lacquer and terbinafine 7.8% lacquer were applied to mycotic nails (n = 17); nail sections were prepared, and MALDI-FTICR analysis was performed. Based on the MICs of amorolfine and terbinafine needed to kill 90% (MIC90) of Trichophyton rubrum, the fold differences between the MIC90 and the antifungal concentrations in the nails (the multiplicity of the MIC90) were calculated overall and for the keratin-unbound fractions.

RESULTS

Both amorolfine and terbinafine penetrated the entire thickness of the nail. The mean concentration across the entire nail section 3 h following terbinafine treatment was 1414 μg/g of tissue (equivalent to 4.9 mM) compared with 780 μg/g (2.5 mM) following amorolfine treatment (not significantly different; p = 0.878). The median multiplicity of the MIC90 was significantly higher in amorolfine- than terbinafine-treated nails overall (191 vs. 48; p = 0.010) and for the keratin-unbound fractions only (7.4 vs. 0.8; p = 0.002).

CONCLUSION

In this ex vivo study, MALDI-FTICR demonstrated that, although amorolfine 5% and terbinafine 7.8% had similar distribution profiles, both penetrating from the surface to the nail bed, the concentration of amorolfine in the nail was significantly higher than that of terbinafine relative to their respective MIC90 values. Clinical studies are required to determine whether these effects translate to a clinical difference in treatment success.

Nail Society of India (NSI) Recommendations for Pharmacologic Therapy of Onychomycosis

Onychomycosis (OM) is the commonest cause of dystrophic nails, responsible for upto 50% of cases. Apart from significantly damaging the nails, quality of life, and self-image of the sufferer, it also acts as a reservoir of fungal infections carrying important implications for emerging recalcitrant dermatophytoses. Treatment of OM is based on guidelines released almost a decade back, in addition to published literature and personal preferences. Hence, an expert group of nail society of India (NSI) worked towards drafting these guidelines aimed at compiling recommendations for pharmacologic treatment of OM, based on scientific evidence, along with practical experience. The group did an extensive analysis of available English language literature on OM published during the period 2014-2022. The evidence compiled was graded and discussed to derive consensus recommendations for practice. Special focus was placed on combination therapies and adjunct therapies, including experience of members, to improve treatment outcomes.

Relevant insights into onychomycosis' pathogenesis related to the effectiveness topical treatment

Onychomycosis (OM) is a fungal infection, responsible for about 50% of nail diseases. OM has been attributed to the ability of fungi to naturally organize themselves into biofilms on nail surfaces. However, little is known about the exact role of the biofilm in the etiopathogenesis of OM, as well as its influence in the permeation of a topical treatment. The objectives of this study were to review the literature for topical OM treatments in clinical trials, assess the efficiency of these treatments, and discuss factors that could affect the success of these treatments. First, a systematic search of articles published in the MEDLINE database (PubMed) between January 2010 and December 2019 was conducted, focusing on drugs under clinical trials for the topical treatment of OM. Of the publications selected, it was clear that none of them had considered the fungi organized in biofilm. Therefore, we reflected on some important variables involved in OM, such as the nail structure and the mechanism of fungal invasion. Some methods, such as histopathologic analysis and spectroscopy techniques, were found to be effective in the detection of nail biofilm, and could be used in future drug permeation studies. This review allowed us to conclude that novel antifungals for the topical treatment of OM must consider the drug to permeate through biofilm. Natural products, such as propolis, seem strong candidates in this respect.