Fifth toenail clinical response to systemic antifungal therapy is not a marker of successful therapy for other toenails with onychomycosis

Antifungal Nail Lacquer for Enhanced Transungual Delivery of Econazole Nitrate

The fungal disease of the nail, onychomycosis, which is also the most prevalent nail disturbance, demands effective topical treatment options considering the possible adverse effects of systemic antifungal therapy. The current work is focused on development of an adhesive and resistant, drug-delivering and permeation-enhancing polymeric film containing econazole nitrate (ECN) for topical antifungal treatment. The development of the lacquer formulation was guided by the Quality by Design approach to achieve the critical quality attributes needed to obtain the product of desired quality. Eudragit RSPO at 10% w/w was found to be the ideal adhesive polymer for the application and an optimal permeation-enhancing lacquer formulation was achieved by the optimization of other formulation excipients, such as plasticizer and the solvent system. Additionally, novel experimental enhancements introduced to the research included refined D₅₀ drying time and drying rate tests for lacquer characterization as well as a multi-mechanism permeation-enhancing pre-treatment. Moreover, a practical implication was provided by a handwashing simulation designed to test the performance of the lacquer during actual use. In vitro drug release testing and ex vivo nail permeation testing demonstrated that the optimized nail lacquer performed better than control lacquer lacking the permeation enhancer by achieving a faster and sustained delivery of ECN. It can be concluded that this is a promising drug delivery system for topical antifungal treatment of onychomycotic nails, and the novel characterization techniques may be adapted for similar formulations in the future.

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.

Clinical significance of Candida isolation from dystrophic fingernails

BACKGROUND

Candida onychomycosis mostly involves fingernails. Yet, in contrast to dermatophytes, Candida isolation from dystrophic fingernails does not prove casualty, as sample contamination and non-pathogenic Candida growth occur. Characterising treatment outcome of Candida-positive dystrophic nails is crucial to avoid unnecessary treatment.

OBJECTIVE

To investigate predicators associated with treatment outcome among Candida-positive dystrophic fingernails.

PATIENTS AND METHODS

A retrospective cohort study was carried out among 108 adults with Candida-positive dystrophic fingernails not cured with adequate systemic anti-fungal course. Diagnosis was based on a single mycological culture. Patients with treatment failure (n = 85; 78.7% of the cases) were compared to patients with partial response (mild to almost cure; n = 23; 21.3% of the cases) at 9 to 12 months following treatment initiation.

RESULTS

Treatment failure was significantly associated with primary onycholysis (odds ratio [OR] 2.8; 95% confidence interval [CI] 1.1-7.4) and prolonged dystrophy (12.8 vs. 3.7 years in average), compared to partial treatment response. Non-responders had lower odds to present with distal lateral subungual onychomycosis, compared to partial responders (OR 0.3; 95% CI 0.1-0.7). Demographic and mycological characteristics, as well as number of nails affected, co-presence of paronychia, and treatment regime were not found to be associated with treatment response.

CONCLUSION

Candida-positive primary onycholysis was shown to be non-responsive to systemic anti-fungal treatment, suggesting that anti-fungal treatment is not indicated. For other clinical scenarios, high proportions of treatment non-response suggest that determining causality of Candida should not be based on a single positive mycological culture.

Liquid chromatography-tandem mass spectrometry is effective for analysis of ergosterol in fungal-infected nails

BACKGROUND

Identification of onychomycosis is mainly based on clinical diagnosis with auxiliary diagnostic methods such as potassium hydroxide (KOH) microscopy, periodic acid-Schiff staining or fungal culture. However, each method is limited by its sensitivity and specificity.

AIM

To develop a new test method using the common fungal end product, ergosterol, and investigate if it can be used as a new diagnostic tool.

METHODS

We collected consecutive data from 20 participants with nail problems. Following clinical diagnosis, samples were taken for KOH microscopy and for mass spectrometry (MS) to check for the presence of ergosterol.

RESULTS

Of the 20 cases collected, 7 were positive for fungal infection by MS. Four of these were already suspected to have onychomycosis, whereas one of the remaining three subjects was presumed to have dry nail and the other two to have onycholysis. The MS test seemed to be better at detecting combinations of nail conditions. Conversely, of the five patients clinically diagnosed as having onychomycosis, four had a positive MS result, whereas the fifth had negative results on both KOH and MS. Two other participants had a positive KOH test and were also found to have positive MS results.

CONCLUSION

Detection of the presence of ergosterol by MS seems to be a useful tool for confirming onychomycosis. However, further studies are needed to verify the sensitivity and specificity of this MS method.

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.

Variability in Systemic Treatment Efficacy for Onychomycosis: Information That Clinical Studies Do Not Impart to the Office Dermatologist

Wide differences in the cure rates of onychomycosis in various clinical studies can be avoided if we bear in mind some insights that will help us make study results more consistent. We suggest less rigid criteria in defining the cure rate, the inclusion of all toenails in studies, and the exclusion of nails with a history of trauma. Rather than address patients as a homogenous group, regardless of age, we suggest dividing them into age groups. Researchers should not forget inflammatory diseases that can imply changes on the nails and should take into account the duration of onychomycosis, nail changes caused by asymmetry, and the possibility of dermatophytoma.