How often does oral treatment of toenail onychomycosis produce a disease-free nail? An analysis of published data

Onychomycosis: Old and New

Onychomycosis is a common chronic fungal infection of the nail that causes discoloration and/or thickening of the nail plate. Oral agents are generally preferred, except in the case of mild toenail infection limited to the distal nail plate. Terbinafine and itraconazole are the only approved oral therapies, and fluconazole is commonly utilized off-label. Cure rates with these therapies are limited, and resistance to terbinafine is starting to develop worldwide. In this review, we aim to review current oral treatment options for onychomycosis, as well as novel oral drugs that may have promising results in the treatment of onychomycosis.

Excellent Response of Dermatophytoma and Nail Splitting to Nail Plate Debridement Plus Topical Ciclopirox Olamine 1% Solution

Onychomycosis often presents as thickened, discolored nails. Usually, one or both great toenails are affected. Eventually, the nail plate becomes friable and may split and break up, often due to trauma or invasion of the plate by dermatophytes that have keratolytic properties. Dermatophytoma is a unique feature of onychomycosis that occurred by abundant fungal filaments and spores forming a fungal ball under the nail plate. It is often refractory to traditional therapy. Based on the clinical and mycological examination, a case of onychomycosis in a 45-year-old woman presented as dermatophytoma with longitudinal nail splitting caused by Trichophyton rubrum is presented. The case was successfully treated with nail plate debridement plus topical ciclopirox olamine 1% solution. Nail debridement was performed using a 15-scalpel blade to remove the affected nail portion with the underlying subungual debris to enhance the effect of topical ciclopirox 1% solution which was then applied 3 times daily to the debrided area. Follow-up visits with nail photography were planned every 2 weeks after the procedure to check treatment progress. A complete clinical resolution was achieved after 5 months. This treatment option can be advocated for similar nail conditions avoiding unnecessary and expensive lines of treatment.

A Practical Guide to Curing Onychomycosis: How to Maximize Cure at the Patient, Organism, Treatment, and Environmental Level

Onychomycosis is a fungal nail infection caused by dermatophytes, non-dermatophyte molds, and yeasts. Treatment of this infection can be difficult, with relapse likely to occur within 2.5 years of cure. The objective of this article is to review factors that can impact cure and to suggest practical techniques that physicians can use to maximize cure rates. Co-morbidities, as well as disease severity and duration, are among the many patient factors that could influence the efficacy of antifungal therapies. Furthermore, organism, treatment, and environmental factors that may hinder cure include point mutations, biofilms, affinity for non-target enzymes, and exposure to fungal reservoirs. To address patient-related factors, physicians are encouraged to conduct confirmatory testing and treat co-morbidities such as tinea pedis early and completely. To combat organism-focused factors, it is recommended that disruption of biofilms is considered, and drugs with multiple routes of delivery and unique mechanisms of action are prescribed when traditional agents are not effective. Extending follow-up periods, using combination treatments, and considering pulse regimens may also be of benefit. Through these practical techniques, physicians can maximize cure and limit the risk of relapse and re-infection.

A practical application of onychomycosis cure - combining patient, physician and regulatory body perspectives

Due to the high relapse rates and the rise of predisposing factors, the need for curing onychomycosis is paramount. To effectively address onychomycosis, the definition of cure used in a clinical setting should be agreed upon and applied homogeneously across therapies (e.g. oral, topical and laser treatments). In order to determine what is or what should be used to define cure in a clinical setting, a literature search was conducted to identify methods used to evaluate treatment success. The limitations, strengths, prevalence and utility of each outcome measure were investigated. Seven ways to measure treatment success were identified; mycological cure, patient/investigator assessments, complete cure, quality of life instruments, severity indexes, clinical cure and temporary clearance. Despite its shortcomings, mycological cure is the most objective and consistent outcome measure used across onychomycosis studies. It is suggested that diagnostic goals of onychomycosis should be used to define cure in a clinical setting. Modifications to outcome measures such as incorporating molecular-based techniques could be a future avenue to explore.

Efinaconazole 10% solution in the treatment of onychomycosis of the toenails

BACKGROUND

Efinaconazole 10% solution is a new triazole antifungal agent developed for the topical treatment of onychomycosis. This article reviews the pooled results of the two pivotal clinical trials of this drug that have been performed in the United States, Canada, and Japan.

METHODS

The two studies of 1,655 patients were both double-blind, vehicle-controlled, parallel-group, randomized, multicenter studies designed to determine the efficacy and safety of efinaconazole 10% solution in the treatment of mild-to-moderate onychomycosis of the toenails caused by dermatophytes. Treatment was provided once daily for 48 weeks, and the primary end point was at week 52.

RESULTS

The combined results show a 56% mycologic cure rate compared with 17% for vehicle at week 52. Clinical treatment success was achieved in 43% of patients treated with efinaconazole 10% solution at follow-up (week 52). Clinical treatment success was achieved in 47% of patients. As expected for a topical agent, the use of efinaconazole 10% solution was found to be safe, with mild, transient irritation at the site of application reported as the most common adverse event.

CONCLUSIONS

The efficacy and safety profile of efinaconazole 10% solution suggests that it may represent an important advance in the topical treatment of onychomycosis. Further studies will help us better understand the role of this agent for the treatment of this widespread podiatric medical condition.

Novel investigational therapies for onychomycosis: an update

INTRODUCTION

Onychomycosis is an infection of the nail plate that is prevalent among the ageing population. Onychomycosis is difficult to treat with low initial cure rates, high rates of relapse, and reinfection. Present treatment options include oral and topical therapies, with oral therapies yielding better results. However, there has been a greater emphasis on the development of topical antifungal therapies as they have fewer side effects and drug interactions.

AREAS COVERED

This review summarizes new and reformulated drugs. Results from in vitro studies to Phase III clinical trials are discussed. Novel drugs include: the oral azole VT-1161, the topical azole efinaconazole, the benzoxaborole tavaborole, reformulations of terbinafine P-3058 and LI-P, novel inhibitor of succinate dehydrogenase ME1111, and off-label use of tazarotene. Enhanced permeation of the morpholine amorolfine through the nail plate is also discussed using ultraviolet (UV) curable gels, and a fractional CO2 laser.

EXPERT OPINION

Novel topical antifungals and the reformulation of current antifungals have demonstrated marked improvement in nail penetration. Current research has an emphasis on topical therapies due to their minimized risk for adverse effects and higher patient demand. Nevertheless, few topical agents have surfaced in the past few years and the investigation of efficacious combination therapies may become more important.

Tazarotene as alternative topical treatment for onychomycosis

Background

Distal and lateral onychomycoses are the most frequent forms of onychomycosis, causing subungual hyperkeratosis that usually limits local penetration of antimycotic drugs. Tazarotene exerts anti-inflammatory and immune-modulating activities toward both infective agents and damaged keratinocytes. Given the well-documented efficacy of tazarotene on hyperkeratotic nail psoriasis, we investigated its therapeutic use in onychomycosis.

Patients and methods

We designed a preliminary open clinical trial in patients affected by distal and lateral subungual onychomycosis of the toenails and verified the fungistatic activity of tazarotene in vitro. Fifteen patients were treated with topical tazarotene 0.1% gel once per day for 12 weeks. Mycological cultures and potassium hydroxide stains of nail samples were performed at the beginning and at the end of the study. Treatment was considered effective when clinical healing and negative mycological culture were obtained. Onycholysis, nail bed discoloration, and subungual hyperkeratosis were measured using standardized methodologies and analyzed by means of Mann–Whitney test and analysis of variance. Fungistatic activity of tazarotene was evaluated by disk diffusion assay.

Results

Six patients (40%) reached a mycological cure on target nail samples already after 4 weeks of treatment. Complete clinical healing and negative cultures were reached in all patients at week 12, with a significant improvement of all clinical parameters of the infected nails. Disk diffusion assay after 48 hours of incubation with tazarotene solution showed a central area of inhibition in all examined fungal cultures.

Conclusion

Our results documented a good clinical outcome using topical tazarotene 0.1% gel in distal and lateral subungual onychomycosis and its fungistatic activity of tazarotene in vitro. The majority of patients appeared cured at a 6-month follow-up. The efficacy and safety of tazarotene must be confirmed on a larger number of patients, although already documented in nail psoriasis patients often affected by onychomycosis.

VT-1161 dosed once daily or once weekly exhibits potent efficacy in treatment of dermatophytosis in a guinea pig model

Current therapies used to treat dermatophytoses such as onychomycosis are effective but display room for improvement in efficacy, safety, and convenience of dosing. We report here that the investigational agent VT-1161 displays potent in vitro antifungal activity against dermatophytes, with MIC values in the range of ≤0.016 to 0.5 μg/ml. In pharmacokinetic studies supporting testing in a guinea pig model of dermatophytosis, VT-1161 plasma concentrations following single oral doses were dose proportional and persisted at or above the MIC values for at least 48 h, indicating potential in vivo efficacy with once-daily and possibly once-weekly dosing. Subsequently, in a guinea pig dermatophytosis model utilizing Trichophyton mentagrophytes and at oral doses of 5, 10, or 25 mg/kg of body weight once daily or 70 mg/kg once weekly, VT-1161 was statistically superior to untreated controls in fungal burden reduction (P < 0.001) and improvement in clinical scores (P < 0.001). The efficacy profile of VT-1161 was equivalent to those for doses and regimens of itraconazole and terbinafine except that VT-1161 was superior to itraconazole when each drug was dosed once weekly (P < 0.05). VT-1161 was distributed into skin and hair, with plasma and tissue concentrations in all treatment and regimen groups ranging from 0.8 to 40 μg/ml (or μg/g), at or above the MIC against the isolate used in the model (0.5 μg/ml). These data strongly support the clinical development of VT-1161 for the oral treatment of onychomycosis using either once-daily or once-weekly dosing regimens.

Cutaneous fungal infections in the elderly

This article summarizes the common, superficial, cutaneous, fungal infections that are found in older adults. The epidemiology, classic appearance, and current treatments of these fungal infections are discussed. These common skin pathogens occur in many older adults.

Comparison of diagnostic methods in the evaluation of onychomycosis

Onychomycosis is a common nail problem, accounting for up to half of all nail diseases. Several nail disorders may mimic the onychomycosis clinically. Therefore, a sensitive, quick, and inexpensive test is essential for screening nail specimens for the administration of the proper drug. The aim of this study was to compare 4 different diagnostic methods in the evaluation of onychomycosis and to determine their sensitivity, specificity, positive predictive value, and negative predictive value. In a cross-sectional study, nail specimens were collected from 101 patients suspected to have onychomycosis during a 14-month period. The nail specimens were examined using potassium hydroxide (KOH) 20 %, KOH-treated nail clipping stained with periodic acid-Schiff (KONCPA), and calcofluor white (CFW) stain, and grew a fungal culture. The culture was chosen as the gold standard for statistical analysis using the McNemar and chi-square tests. Out of 101 patients, 100 (99 %) patients had at least 1 of the 4 diagnostic methods positive for the presence of organisms. The positive rates for the fungal culture, KOH preparation, CFW, and KONCPA were 74.2, 85.1, 91.09, and 99.01 %, respectively. The sensitivity and negative predictive value of KONCPA was 100 %. KONCPA was the most sensitive among the tests and was also superior to other methods in its negative predictive value. KONCPA was easy to perform, rapid, and gave significantly higher rates of detection of onychomycosis compared to the standard methods of KOH preparation and fungal culture. Therefore, KONCPA should be the single method of choice for the evaluation of onychomycosis.

Confocal laser scanning microscopy as a new valuable tool in the diagnosis of onychomycosis - comparison of six diagnostic methods

Onychomycosis is common and can mimic several different nail disorders. Accurate diagnosis is essential to choose the optimum antifungal therapy. The aim of this study was to evaluate the use of confocal laser scanning microscopy (CLSM) and optical coherence tomography (OCT) as new non-invasive diagnostic tools in onychomycosis and to compare them with the established techniques. In a prospective trial, 50 patients with suspected onychomycosis and 10 controls were examined by CLSM and OCT. Parallel KOH preparation, culture, PAS-staining and PCR were performed. PCR showed the highest sensitivity, followed by CLSM, PAS and KOH preparation. OCT offered the second best sensitivity but displayed the lowest specificity. CLSM and KOH preparation showed a high specificity and CLSM offered the best positive predictive value, similar to KOH preparation and OCT. Fungal culture showed the lowest sensitivity and the worst negative predictive value, yet culture and PCR are the only techniques able to identify genus and species. In summary, CLSM was comparable to PAS staining and superior to KOH preparation. Due to the low specificity we assess OCT not as appropriate. In the differentiation of species PCR outplays the fungal culture in terms of time and sensitivity.

Efficacy, safety and tolerability of topical terbinafine nail solution in patients with mild-to-moderate toenail onychomycosis: results from three randomized studies using double-blind vehicle-controlled and open-label active-controlled designs

BACKGROUND

Terbinafine nail solution (TNS) was developed for the treatment of onychomycosis.

OBJECTIVE

To assess the efficacy of TNS vs. vehicle and amorolfine 5% nail lacquer.

METHODS

Subjects with mild-to-moderate toe onychomycosis (25% to ≤75% nail-involvement, matrix uninvolved) were randomized to receive either TNS or vehicle in two double-blind studies, and to TNS or amorolfine in an active-controlled, open-label study. Primary endpoint was complete cure (no residual clinical involvement and negative mycology) at week 52. Secondary endpoints were mycological cure (negative mycology defined as negative KOH microscopy and negative culture) and clinical effectiveness (≤10% residual-involvement and negative mycology) at week 52.

RESULTS

Complete cure was not different between TNS vs. vehicle and amorolfine. Mycological cure was higher with TNS vs. vehicle, as was clinical effectiveness with TNS vs. vehicle, and TNS and amorolfine were not different for secondary efficacy endpoints. Patients achieving mycological cure had a better clinical outcome, and efficacy was improved in subjects with milder disease. Post hoc analysis suggests that nail thickness is an important prognostic factor. Moreover, mycological cure may require 6 months of treatment regimen while complete cure and clinical effectiveness may be achievable only after 10 months. A simulation study suggests that longer treatment duration would have resulted in higher complete cure with TNS vs. vehicle. Study treatments were well-tolerated.

CONCLUSION

Primary efficacy objectives were not met in the studies reported herein. Possible reasons for failure to achieve significant outcomes include insufficient length of treatment; stringency of primary endpoint and severity of nail involvement of study population.

Diagnosis of Trichophyton rubrum from onychomycotic nail samples using polymerase chain reaction and calcofluor white microscopy

BACKGROUND

A high rate of false-negative dermatophyte detection is observed when the most common laboratory methods are used. These methods include microscopic observation of potassium hydroxide-digested nail clippings and culture methods using agar-based media supplemented with cycloheximide, chloramphenicol, and gentamicin to isolate dermatophytes. Microscopic detection methods that use calcofluor white staining or periodic acid-Schiff staining may also be substituted for and have previously been reported to be more sensitive than potassium hydroxide-digested nail clippings.

METHODS

Trichophyton rubrum infections were detected directly from nails in a double-round polymerase chain reaction assay that uses actin gene-based primers. This method was compared with detection of fungal hyphae by using calcofluor white fluorescence microscopy of nail samples collected from 83 patients with onychomycosis who were undergoing antifungal drug therapy.

RESULTS

Twenty-six of 83 samples (31.3%) were found to be positive by calcofluor white fluorescence microscopy, and 21 of 83 samples (25.3%) yielded positive results for T rubrum when actin gene-based primers in a double-round polymerase chain reaction assay were used. When calcofluor white fluorescence microscopy and polymerase chain reaction assay were used, the combined detection was 46.9% compared with 31.3% when calcofluor microscopy and culture of nail samples on Sabouraud's dextrose agar supplemented with cycloheximide, chloramphenicol, and gentamicin were used.

CONCLUSIONS

These results suggest that the use of a direct DNA protocol is an alternative method for detecting Trichophyton infections. When this protocol is used, the presence of T rubrum DNA is directly detected. However, the viability of the dermatophyte is not addressed, and further methods need to be developed for the detection of viable T rubrum directly from nail samples.

The significance of itraconazole for treatment of fungal infections of skin, nails and mucous membranes

Itraconazole is an antifungal drug from the triazole group with distinct in vitro activity against dermatophytes, yeasts and some molds. Itraconazole has a primarily fungistatic activity. Itraconazole accumulates in the stratum corneum and in nail material due to its high affinity to keratin, as well as in sebum and vaginal mucosa. Together with terbinafine and fluconazole, itraconazole belongs to the modern highly effective systemic antifungal drugs with a favorable risk-benefit ratio and for this reason is a preferred therapy option for fungal infections of skin, nails and mucous membranes. Compared to terbinafine in the treatment of fingernail and toenail fungal infections, itraconazole offers the advantage of a broad antifungal spectrum and better effectiveness against onychomycosis caused by yeasts yet appears inferior with regard to the more common dermatophyte infections. Itraconazole constitutes an important therapy option, along with fluconazole, terbinafine, ketoconazole and griseofulvin, for the treatment of dermatophyte infections of glabrous skin (tinea pedis, tinea manuum, tinea corporis and tinea cruris) in adults following unsuccessful topical therapy. In the oral therapy of tinea capitis, itraconazole plays an especially important role, in particular for disease caused by Microsporum canis (for children, however, only off-label use is feasible currently). In the treatment of oropharyngeal candidiasis, candidiasis of the skin and vulvovaginal candidiasis, itraconazole and fluconazole are the preferred treatment options in cases in which topical therapy has proven unsuccessful.

The safety of oral antifungal treatments for superficial dermatophytosis and onychomycosis: a meta-analysis

PURPOSE

We estimated the absolute risks of treatment termination and incidence of adverse liver outcomes among all commonly used oral antifungal treatments for superficial dermatophytosis and onychomycosis.

METHODS

MEDLINE, EMBASE, and Cochrane Library were searched to identify randomized and nonrandomized controlled trials, case series, and cohort studies published before December 31, 2005. Two reviewers independently applied selection criteria, performed quality assessment, and extracted data. Treatment arms with the same regimen in terms of drug, type (continuous or intermittent), and dosage were combined to estimate the risk of an outcome of interest.

RESULTS

We identified 122 studies with approximately 20,000 enrolled patients for planned comparison. The pooled risks (95% confidence intervals) of treatment discontinuation resulting from adverse reactions for continuous therapy were 3.44% (95% confidence interval [CI], 2.28%-4.61%) for terbinafine 250 mg/day; 1.96% (95% CI, 0.35%-3.57%) for itraconazole 100 mg/day; 4.21% (95% CI, 2.33%-6.09%) for itraconazole 200 mg/day; and 1.51% (95% CI, 0%-4.01%) for fluconazole 50 mg/day. For intermittent therapy, the pooled risks were as follows: pulse terbinafine: 2.09% (95% CI, 0%-4.42%); pulse itraconazole: 2.58% (95% CI, 1.15%-4.01%); intermittent fluconazole 150 mg/week: 1.98% (95% CI, 0.05%-3.92%); and intermittent fluconazole 300 to 450 mg/week: 5.76% (95% CI, 2.42%-9.10%). The risk of liver injury requiring termination of treatment ranged from 0.11% (continuous itraconazole 100 mg/day) to 1.22% (continuous fluconazole 50 mg/day). The risk of having asymptomatic elevation of serum transaminase but not requiring treatment discontinuation was less than 2.0% for all treatment regimens evaluated.

CONCLUSION

Oral antifungal therapy against superficial dermatophytosis and onychomycosis, including intermittent and continuous terbinafine, itraconazole, and fluconazole, was associated with a low incidence of adverse events in an immunocompetent population.

Topical application of acidified nitrite to the nail renders it antifungal and causes nitrosation of cysteine groups in the nail plate

BACKGROUND

Topical treatment of nail diseases is hampered by the nail plate barrier, consisting of dense cross-linked keratin fibres held together by cysteine-rich proteins and disulphide bonds, which prevents penetration of antifungal agents to the focus of fungal infection. Acidified nitrite is an effective treatment for tinea pedis. It releases nitric oxide (NO) and other NO-related species. NO can react with thiol (-SH) groups to form nitrosothiols (-SNO).

OBJECTIVES

To determine whether acidified nitrite can penetrate the nail barrier and cure onychomycosis, and to determine whether nitrosospecies can bind to the nail plate.

METHODS

Nails were treated with a mixture of citric acid and sodium nitrite in a molar ratio of 0.54 at either low dose (0.75%/0.5%) or high dose (13.5%/9%). Immunohistochemistry, ultraviolet-visible absorbance spectroscopy and serial chemical reduction of nitrosospecies followed by chemiluminescent detection of NO were used to measure nitrosospecies. Acidified nitrite-treated nails and the nitrosothiols S-nitrosopenicillamine (SNAP) and S-nitrosoglutathione (GSNO) were added to Trichophyton rubrum and T. mentagrophytes cultures in liquid Sabouraud medium and growth measured 3 days later. Thirteen patients with positive mycological cultures for Trichophyton or Fusarium species were treated with topical acidified nitrite for 16 weeks. Repeat mycological examination was performed during this treatment time.

RESULTS

S-nitrothiols were formed in the nail following a single treatment of low- or high-dose sodium nitrite and citric acid. Repeated exposure to high-dose acidified nitrite led to additional formation of N-nitrosated species. S-nitrosothiol formation caused the nail to become antifungal to T. rubrum and T. mentagrophytes. Antifungal activity was Cu(2+) sensitive. The nitrosothiols SNAP and GSNO were also found to be antifungal. Topical acidified nitrite treatment of patients with onychomycosis resulted in > 90% becoming culture negative for T. rubrum.

CONCLUSIONS

Acidified nitrite cream results in the formation of S-nitrosocysteine throughout the treated nail. Acidified nitrite treatment makes a nail antifungal. S-nitrosothiols, formed by nitrosation of nail sulphur residues, are the active component. Acidified nitrite exploits the nature of the nail barrier and utilizes it as a means of delivery of NO/nitrosothiol-mediated antifungal activity. Thus the principal obstacle to therapy in the nail becomes an effective delivery mechanism.

A multicentre, randomized, controlled study of the efficacy, safety and cost-effectiveness of a combination therapy with amorolfine nail lacquer and oral terbinafine compared with oral terbinafine alone for the treatment of onychomycosis with matrix involvement

BACKGROUND

Onychomycosis is common, accounting for up to 50% of all nail disorders. Toenail onychomycosis can cause nail deformity, embarrassment, pain and walking difficulties. Some populations, such as individuals with diabetes, are at higher risk for developing secondary complications such as infections. Treatment takes many months and therapeutic choices can increase clinical effectiveness, lower toxicity and minimize healthcare costs.

OBJECTIVES

Based on the results of a previous pilot study, the objective of the present study was to show, in a larger population, the enhanced efficacy of a combination of amorolfine nail lacquer and oral terbinafine in the treatment of onychomycosis with matrix involvement. In addition, a cost-effectiveness analysis was performed.

METHODS

In this multicentre, randomized, open-label, parallel group study, patients were randomized to receive either a combination of amorolfine hydrochloride 5% nail lacquer once weekly for 12 months plus terbinafine 250 mg once daily for 3 months (AT group) or terbinafine alone once daily for 3 months (T group). The study duration was 18 months including a 6-month treatment-free phase following the 12-month active treatment phase for the AT group and a 15-month treatment-free phase following the 3-month active treatment phase for the T group. The primary efficacy criterion was overall response, dichotomized into success or failure, success being the combination of clinical cure and negative mycology at month 18. This criterion was used as the effectiveness measure in the pharmacoeconomic analysis, conducted from a payer perspective.

RESULTS

In total, 249 patients were included into the study: 120 in the AT group and 129 in the T group. A significantly higher success rate was observed for patients in the AT group relative to those in the T group at 18 months (59.2% vs. 45.0%; P = 0.03). Both treatment regimens were safe and well tolerated. Treatment cost per cured patient was lower for the combination than for terbinafine alone in all countries.

CONCLUSIONS

Study results confirmed that, in the treatment of dermatophytic toenail onychomycosis with matrix involvement, amorolfine nail lacquer in combination with oral terbinafine enhances clinical efficacy and is more cost-effective than terbinafine alone.

Onychomycosis

The guideline on onychomycosis, as passed by the responsible German medical societies, is presented in the present study.

Comparison of direct smear, culture and histology for the diagnosis of onychomycosis

A sensitive and efficient diagnostic strategy is needed to confirm the clinical suspicion of onychomycosis. The purpose of this study was to compare the sensitivity of three most commonly used diagnostic methods for onychomycosis. Nail specimens of 96 patients with clinically suspected onychomycosis were evaluated using potassium hydroxide smear, culture and histology. A positive result of any of these tests was considered confirmatory for fungal infection and the sensitivity of each test as well as various combinations of them was calculated. The diagnosis of onychomycosis was confirmed in 47 patients (48.9%). Histology was the most sensitive single test for the diagnosis of onychomycosis, although its sensitivity (80.8%) was not statistically different from smear (76.5%). Both histology and smear were significantly more sensitive than culture (53.2%). The most sensitive combination of tests, smear plus histology, was 97.8% sensitive with 98% negative predictive value. In conclusion, direct smear combined with histological examination is the most sensitive diagnostic approach for onychomycosis.

Onychomycosis: diagnosis and definition of cure

Until now, there has been no agreement on criteria defining resolution of onychomycosis. Most published reports use clinical and mycological cure, which comprises a completely normal-appearing nail plate, and negative nail culture and microscopy results, as the end point for defining success of therapeutic intervention. Reported here is the definition of onychomycosis, which delineates both primary and secondary criteria for diagnosis of onychomycosis and identifies clinical and laboratory parameters to define a resolved fungal nail infection. Onychomycosis cure is defined by the absence of clinical signs or the presence of negative nail culture and/or microscopy results with one or more of the following minor clinical signs: (1) minimal distal subungual hyperkeratosis; and (2) nail-plate thickening. Clinical signs indicative of persistent onychomycosis at the end of the observation period include (1) white/yellow or orange/brown streaks or patches in or beneath the nail plate; and (2) lateral onycholysis with subungual debris. Although nail appearance will usually continue to improve after cessation of therapy, the nails may have a persistent abnormal appearance even in cases where treatment has been effective.

Onychomycosis Therapies: Strategies to Improve Efficacy

The combination of relatively high treatment failure rates and infection relapse rates warrants consideration of ways in which antifungal therapy can be delivered so that efficacy rates can be improved. These involve the combination of available therapies and/or a modification of treatment regimens.

Pulse versus continuous terbinafine for onychomycosis: A randomized, double-blind, controlled trial

BACKGROUND

Effective treatments for onychomycosis are expensive. Previous studies suggest that less costly, pulsed doses of antifungal medications may be as effective as standard, continuous doses. Terbinafine is the current treatment of choice for toenail onychomycosis.

OBJECTIVE

Our purpose was to determine whether pulse-dose terbinafine is as effective as standard continuous-dose terbinafine for treatment of toenail onychomycosis.

METHODS

We conducted a double-blind, randomized, noninferiority, clinical intervention trial in the Minneapolis Veterans Affairs Medical Center. The main inclusion criteria for participants were a positive dermatophyte culture and at least 25% distal subungual clinical involvement. Six hundred eighteen volunteers were screened; 306 were randomized. Terbinafine, 250 mg daily for 3 months (continuous) or terbinafine, 500 mg daily for 1 week per month for 3 months (pulse) was administered. The primary outcome measure was mycological cure of the target toenail at 18 months. Secondary outcome measures included clinical cure and complete (clinical plus mycological) cure of the target toenail and complete cure of all 10 toenails.

RESULTS

Results of an intent-to-treat analysis did not meet the prespecified criterion for noninferiority but did demonstrate the superiority of continuous-dose terbinafine for: mycological cure of the target toenail (70.9% [105/148] vs 58.7% [84/143]; P =.03, relative risk [RR] of 1.21 [95% confidence interval (CI), 1.02-1.43]); clinical cure of the target toenail (44.6% [66/148] vs 29.3% [42/143]; P =.007, RR =1.52 [95% CI, 1.11-2.07); complete cure of the target toenail (40.5% [60/148] vs 28.0% [40/143]; P =.02, RR=1.45 [95% CI, 1.04-2.01); and complete cure of all 10 toenails (25.2% [36/143] vs 14.7% [21/143]; P =.03, RR =1.71 [95% CI, 1.05-2.79). Tolerability of the regimens did not differ significantly between the groups (chi2 =1.63; P =.65).

LIMITATIONS

The study population primarily consisted of older men with severe onychomycosis.

CONCLUSIONS

This study demonstrated the superiority of continuous- over pulse-dose terbinafine. We also found this expensive therapy to be much less effective than previously believed, particularly for achieving complete cure of all 10 toenails.

Treatment options - development of consensus guidelines

BACKGROUND

There are currently three main treatment strategies for onychomycosis: topical, oral and combination. Amorolfine nail lacquer appears to be the most effective form of topical monotherapy. However, the best mycological and clinical cure rates are obtained with combination therapy. Combination therapy increases antifungal spectrum, fungicidal activity and safety. New antifungals (triazoles and echinocandins) were recently developed, enabling new protocols.

OBJECTIVES

To review available therapies. To design an algorithm for the management of onychomycoses in daily practice.

RESULTS

Therapeutic choice should be based on numerous factors including patient's age and health, aetiology, extent of involvement and clinical form. The consensus was that topical monotherapy is recommended when < 50% of the nail is affected without matrix area involvement. Oral monotherapy or combination therapy is indicated when > 50% of the nail, including the matrix area, is involved. Topical treatments should not be used alone when topical drug transport is suboptimal (i.e. when dermatophytoma, onycholysis or spikes are present). Chemical or mechanical removal should also be considered whenever applicable (interruption of drug transport).

CONCLUSION

In conclusion, treatment decision-making tools (e.g. an illustrated booklet or CD-ROM presenting each type of onychomycosis and criteria to be considered before selecting treatment regimen) would be valuable supports for the successful treatment of onychomycoses.

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.

Terbinafine is more effective than itraconazole in treating toenail onychomycosis: results from a meta-analysis of randomized controlled trials

BACKGROUND

Toenail onychomycosis is a challenge for clinicians to treat, and this challenge is compounded by conflicting information in the medical literature concerning the efficacy of the two principal agents used in its treatment: terbinafine and itraconazole.

OBJECTIVE

The purpose of this meta-analysis is to compare the efficacy of terbinafinewith that of itraconazole in the treatment of toenail onychomycosis caused by dermatophytes.

METHODS

A Medline search was performed for all English language publications from 1966 to June 1999 on the use of terbinafine and itraconazole in the treatment of toenail onychomycosis. Included were randomized studies in which subjects received no less than 3 months (or cycles) and no more than 4 months (or cycles) of either terbinafine or itraconazole. Data were abstracted and statistical analyses (random effects model, fixed effects model, and Peto's method) were applied.

RESULTS

Thirteen studies were included from the original literature review of 1636 total referenced reports; four studies did not fulfill our inclusion or exclusion criteria. The primary analysis of six studies directly comparing terbinafine to itraconazole resulted in an odds ratio ranging from 1.8 (95% CI = 1.8, 2.8) to 2.9 (1.9, 4.1). The secondary analysis of three studies comparing either itraconazole or terbinafine to placebo estimated an odds ratio of 1.1-1.7. The former shows that terbinafine is 80%-190% more likely to result in mycologic cure than is itraconazole; the latter demonstrates a 10%-70% greater likelihood. The difference between the relative efficacies of terbinafine and itraconazole was highly statistically significant (p < 0.0001).

CONCLUSION

Meta-analysis of the published worldwide literature finds that terbinafine is significantly more effective than itraconazole at achieving mycologic cure of toenail onychomycosis.

Action mechanisms of modern antifungal agents and resulting problems in the management of onychomycosis

Successful treatment of onychomycosis in the infection site depends not only on achieving the minimal inhibitory concentration (MIC) of the antifungal agent, usually determined on fresh, proliferating fungal strains, but also on the effectivity against fungal spores dormant in nail keratin. Ciclopiroxolamine and terbinafine were investigated for their fungicidal properties against proliferating and dormant dermatophyte strains. While ciclopiroxolamine was 100% effective against Trichophyton mentagrophytes (50 microg ml(-1)) and Microsporum canis (5 microg ml(-1)) both in the proliferative and dormant phase after 5 days of incubation, the same result was achieved under identical test conditions with 0.002 microg ml(-1) terbinafine using T. mentagrophytes as test organism in the proliferative and 2.0 microg ml-1 in the dormant phase. The terbinafine concentrations of 0.52 microg g(-1) measured in the nail are well below 2.0. This explains the high treatment failure and relapse rates observed under monotherapy of toenail onychomycosis even with modern antifungals. Consequently, combined therapy is recommended, beginning with atraumatic removal of the affected toenails and continuing with an antifungal nail lacquer combined with a systemic antifungal.

Prediction of outcome in the treatment of onychomycosis

Patients with toenail onychomycosis remain a therapeutic challenge despite the introduction of new systemic therapies. Around 20% of patients remain uncured even with optimal oral therapy, but the reasons for treatment failure are unclear. Thus far there are no data to suggest that treatment failures can be identified on the basis of their presenting features or progress during treatment. In a series of patients, we have attempted to identify clinical parameters that determine the patient response to 12 weeks of oral terbinafine for confirmed dermatophyte onychomycosis. As part of a dose-defining randomized multicentre study, 35 patients were followed for 48 weeks. The unaffected nail length, growth rate, hyperkeratosis, onycholysis and presence of a dermatophytoma were assessed prospectively. To confirm our findings, at the end of the study period we analysed retrospectively photographs that had been taken regularly throughout the trial. The average degree of hyperkeratosis was less severe in the group achieving a disease-free nail, meaning clinical and mycological cure. For mycological cure alone, no predictive factors could be identified.

A randomized trial of amorolfine 5% solution nail lacquer in association with itraconazole pulse therapy compared with itraconazole alone in the treatment of Candida fingernail onychomycosis

BACKGROUND

Treatment failures and relapses are not uncommon in onychomycosis. Therefore, it is worthwhile to consider the combination of systemic and topical antifungals to improve the cure rates further and to reduce the duration of systemic treatment.

OBJECTIVES

To evaluate and compare itraconazole pulse therapy combined with amorolfine with itraconazole alone in the treatment of Candida fingernail onychomycosis.

METHODS

Ninety patients with moderate to severe Candida fingernail onychomycosis were randomized into two treatment groups of 45 subjects each. Group 1 received itraconazole pulse therapy for 2 months and applied amorolfine 5% solution nail lacquer for 6 months, while group 2 received monotherapy with three pulses of itraconazole. The primary efficacy criterion was the result of mycological examination at 3 months. The secondary criterion was the combined mycological and clinical response at 9 months. A pharmacoeconomic analysis was also performed to compare the cost-effectiveness of combined therapy vs. monotherapy.

RESULTS

Eighty-five patients were analysed (73 women and 12 men, mean +/- SD age 44.2 +/- 12.9 years). Patients had a mean +/- SD of 3.64 +/- 2.0 nails involved and 228.6 +/- 148.0 mm2 of their nail surface diseased. The mean duration of onychomycosis was 11 months. Paronychial involvement was evident in 71 patients. C. albicans was isolated in 85 cases, C. parapsilosis in three and other Candida species in two cases. Side-effects were uncommon and in only one case led to withdrawal. At the 3-month visit, mycological cure was seen in 32 (74%) of 43 patients in group 1 and in 25 (60%) of 42 patients in group 2. At the 9-month visit, a global cure was seen in 40 patients (93%) in group 1 and in 34 patients (81%) in group 2. Statistical analysis showed no statistically significant difference (P > 0.1) between the two treatment groups. The cost per cure ratio was 1.63 and 1.70euro for groups 1 and 2, respectively.

CONCLUSIONS

The combination of amorolfine and oral itraconazole, which interfere with different steps of ergosterol synthesis, exhibited substantial synergy. Compared with oral itraconazole alone, the combination achieved greater mycological cure and increased total cure rate. However, no statistically significant difference was documented for this number of observations. Combination treatment with amorolfine and two pulses of itraconazole is at least as safe and effective as three pulses of itraconazole, with a lower cost per patient. In our opinion, the addition of amorolfine to oral itraconazole pulse therapy is of value in the treatment of moderate to severe Candida fingernail onychomycosis.

Nail abrasion

Certain diseases of the nail complex cause hyperkeratosis or alterations of the shape of the nail plate. These conditions may be painful, may decrease the penetration of topical medicaments and may be ugly. The nail plate abrasion, performed with dermabrader device or sandpaper, has application in patients suffering from onychomycosis, psoriasis, subnail infections and haematomas. The technique facilitates the collection of scales for mycological examination, decreases treatment time (of topical monotherapy) for onychomycosis and provides greater comfort for the patient by reducing nail plate thickness. It can also be useful for the partial removal of the nail plate in cases of haematomas and subnail infections. Nail abrasion is an effective and inexpensive method, easily applied in either nail pathologies with hyperkeratosis of the nail plate or in those requiring partial removal of the plate.

Terbinafine: a review of its use in onychomycosis in adults

Terbinafine, an orally and topically active antimycotic agent, inhibits the biosynthesis of the principal sterol in fungi, ergosterol, at the level of squalene epoxidase. Squalene epoxidase inhibition results in ergosterol-depleted fungal cell membranes (fungistatic effect) and the toxic accumulation of intracellular squalene (fungicidal effect). Terbinafine has demonstrated excellent fungicidal activity against the dermatophytes and variable activity against yeasts and non-dermatophyte molds in vitro. Following oral administration, terbinafine is rapidly absorbed and widely distributed to body tissues including the poorly perfused nail matrix. Nail terbinafine concentrations are detected within 1 week after starting therapy and persist for at least 30 weeks after the completion of treatment. Randomized, double-blind trials showed oral terbinafine 250 mg/day for 12 or 16 weeks was more efficacious than itraconazole, fluconazole and griseofulvin in dermatophyte onychomycosis of the toenails. In particular, at 72 weeks' follow-up, the multicenter, multinational, L.I.ON. (Lamisil vs Itraconazole in ONychomycosis) study found that mycologic cure rates (76 vs 38% of patients after 12 weeks' treatment; 81 vs 49% of recipients after 16 weeks' therapy) and complete cure rates were approximately twice as high after terbinafine treatment than after itraconazole (3 or 4 cycles of 400 mg/day for 1 week repeated every 4 weeks) in patients with toenail mycosis. Furthermore, the L.I.ON. Icelandic Extension study demonstrated that terbinafine was more clinically effective than intermittent itraconazole to a statistically significant extent at 5-year follow-up. Terbinafine produced a superior complete cure rate (35 vs 14%), mycologic cure rate (46 vs 13%) and clinical cure rate (42 vs 18%) to that of itraconazole. The mycologic and clinical relapse rates were 23% and 21% in the terbinafine group, respectively, compared with 53% and 48% in the itraconazole group. In comparative clinical trials, oral terbinafine had a better tolerability profile than griseofulvin and a comparable profile to that of itraconazole or fluconazole. Post marketing surveillance confirmed terbinafine's good tolerability profile. Adverse events were experienced by 10.5% of terbinafine recipients, with gastrointestinal complaints being the most common. Unlike the azoles, terbinafine has a low potential for drug-drug interactions. Most pharmacoeconomic evaluations have shown that the greater clinical effectiveness of oral terbinafine in dermatophyte onychomycosis translates into a cost-effectiveness ratio superior to that of itraconazole, fluconazole and griseofulvin.

CONCLUSION

Oral terbinafine has demonstrated greater effectiveness than itraconazole, fluconazole and griseofulvin in randomized trials involving patients with onychomycosis caused by dermatophytes. The drug is generally well tolerated and has a low potential for drug interactions. Therefore, terbinafine is the treatment of choice for dermatophyte onychomycosis.

Prognostic factors of mycological cure following treatment of onychomycosis with oral antifungal agents

BACKGROUND

There is considerable literature on the efficacy and safety of various drugs used in treating onychomycosis; however, little information is available regarding prognostic factors which may be associated with non-response to conventional treatment.

OBJECTIVES

To identify parameters influencing mycological cure at 72 weeks following treatment of toenail onychomycosis with oral antifungal agents.

METHODS

Univariate and multivariate logistic regression analysis from a randomized double-blind controlled trial including 496 patients with toenail onychomycosis caused by dermatophytes.

RESULTS

Baseline parameters including patient's age, gender, weight, number of toenails involved, percentage of nail involvement, duration of infection, history of previous treatment were not associated with mycological cure. In the multivariate prognostic factor analysis based on factors assessed at week 12, positive mycological culture at 12 weeks [odds ratio (OR): 0.583; 95% confidence interval (CI): 0.370-0.918] was negatively associated with mycological cure at 72 weeks. Similarly, in the multivariate prognostic factor analysis based on factors assessed at week 24, positive direct microscopy at 24 weeks (OR: 0.373; 95% CI: 0.211-0.659) and mycological culture at 24 weeks (OR: 0.293; 95% CI: 0.168-0.513) were negatively associated with mycological cure at 72 weeks.

CONCLUSIONS

Mycological culture at 12 and 24 weeks and direct microscopic examination at 24 weeks can help in early identification of patients failing to respond to conventional oral antifungal treatment.