Onychomycosis is a fungal infection of the nail caused by dermatophytes, nondermatophyte moulds (NDMs), or yeast. It is the most common nail disorder observed in clinical practice, with a worldwide prevalence of 5.5% and prevalence in the US estimated to be 2–14%. It has also been estimated that more than 60–70% of onychomycosis infections are caused by dermatophytes, most commonly Trichophyton rubrum.
The dermatophytic onychomycosis (DO) market can be broadly split into oral and topical treatments, the former consisting of terbinafine, itraconazole and fluconazole, while the latter consists of ciclopirox, Bausch Health’s Jublia (efinaconazole) and Sandoz’s Kerydin (tavaborole).
Historically, oral drugs have been the mainstay of DO treatment since 1975 when griseofulvin was launched, due to their greater efficacy and have been genericised for some time, but patient demand for effective topical options led to the launch of Jublia and Kerydin in 2014. Despite the high price of these branded topicals, their efficacy has been found lacking and recent developments have led to research on novel topical therapies. As a result, the US DO market is expected to experience significant growth due to these new pipeline drugs reaching the market, as well as generic versions of Jublia and Kerydin launching, over the next ten years.
Figure: Dermatophytic Onychomycosis Agents in Clinical Development in the US. Credit: GlobalData.
As the DO oral therapies are all genericised, drug developers have focused exclusively on the development of more effective topicals. In late-stage development, Moberg Pharma’s terbinafine-based MOB-015 has recently finished phase three trials and has demonstrated a remarkable 70% mycologic cure rate, matching oral terbinafine in its ability to stamp out the infection. However, it produced a complete cure rate of only 4.5%, which is much lower than that offered by Jublia and Kerydin, due to giving the nail a clouded appearance, thus lowering its prospective patient share over the forecast period.
In phase two of development is Blueberry Therapeutics’ BB2603-om, a spray-on form of terbinafine in nanoparticle form to penetrate the nail and treat the nail in three months, rather than the usual eleven months for most topical therapies. Also in phase two development is Hallux Inc.’s HTS-519, a biodegradable terbinafine micro-insert that is left under the nail for the duration of the eleven months of treatment. Due to all being applied topically, these drugs in development obviate any concerns about potential side effects, unlike systemic treatment, which has been implicated in several drug-drug interactions and hepatic complications.
The DO market will be further bolstered by the genericisation of Jublia and Kerydin in 2021 and 2027, respectively, as sales of these drugs have been massively hampered due to their high cost and the fact that US pharmacies have cut their spending on dermatology. Cheaper generic versions of these drugs will attract a greater number of patients than had access to the branded versions due to patient preference for safer topicals, leading to high sales for generic efinaconazole and tavaborole.
However, key opinion leaders (KOLs) interviewed by GlobalData generally agreed that, despite not resulting in a guaranteed cure, the treatment of DO is fairly straightforward but the lack of patient understanding limits the efficacy of treatment due to patient preference for the topicals and the inability to prevent reinfection is an aspect that pharmaceutical companies need to examine more closely. Overall, the moderate growth of the US DO market over the next decade can be attributed to new drugs, both branded and generic, reaching the market, but is likely to be hampered by the high cost of branded topical therapies.