Emerging drugs for the treatment of onychomycosis

ABSTRACT

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.

KEYWORDS:

• Antifungal
• dermatophyte
• fungus
• itraconazole
• onychomycosis
• terbinafine
• tinea unguium

Article highlights

• Onychomycosis is a chronic, difficult-to-treat fungal infection of the nail that predominantly affects the elderly and immunocompromised: populations that are on the rise globally.

• Oral treatments (terbinafine, itraconazole, and fluconazole) are most effective, but can induce drug-drug interactions and impair liver function.

• Due to the side effects of oral treatments, topical treatments are often preferred (efinaconazole, tavaborole, and their predecessors, ciclopirox and amorolfine); however, they are not as effective due to the nearly impenetrable barrier of the nail.

• Current research is focused on finding alternative treatments that have fewer drug interactions and are less hepatotoxic, as well as treatments that affect different fungal mechanisms to combat antifungal resistance.

• There is competitive, ongoing research on novel systemic and topical treatments, as well as penetration enhancers; that being said, development issues arise due to a lack of interest in researching fungal biology and a perception of triviality of the disease.

• Onychomycosis can be treated with short term oral therapies (~3 months) or long term topical treatments (>1 year) with patient compliance, and recurrence can be prevented through prophylaxis, disinfection of socks and shoes, and wearing footwear in public places.

This box summarizes key points contained in the article.

Declaration of interest

AK Gupta is a clinical trials investigator for Moberg Pharma and Bausch Health Canada and a speaker for Bausch Health Canada. N Stec is an employee of Mediprobe Research Inc., which conducts clinical trials under the supervision of AK Gupta. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.