Hallux is a clinical-stage pharmaceutical company focused on developing a new topical dosage form and route of administration for treating onychomycosis (toenail fungus). To date, prescription treatments for toenail fungus have been either low cure rate topical products that must be applied daily for at least twelve months or oral products that are associated with systemic safety issues.

Hallux’s mission is to provide a highly effective and safe topical product for patients with chronic onychomycosis who have had to live with this disease for years.

The company’s technology delivers high concentrations of the gold standard antifungal terbinafine directly and selectively to the site of infection without introducing it systemically, where it can affect the liver and interact with other drugs that patients may be taking.

Hallux completed a phase 2 clinical study with its first subungual dosage form, HTS-519, in September 2018. The trial evaluated efficacy, safety, and tolerability in 30 moderate-to-severe patients enrolled from a single high volume podiatric clinic.



Onychomycosis is primarily a fungal infection of the nail bed. It is commonly referred to as ‘toenail fungus’ because toenail infections constitute the majority of onychomycosis cases. The infection typically begins as a small white or yellow spot beneath the nail plate causing nail discoloration and thickening and splitting of the nail. Ultimately, the nail plate may detach from the nail bed.

Yellow, Infected, and Ugly Toenails

Onychomycosis is easy to identify as toenails become yellow, thick, and unsightly in appearance. As the fungus in the nail bed proliferates, the resulting damage can result in pain, difficulty in walking and wearing shoes, and social embarrassment due to the ugly appearance of the nails. Untreated onychomycosis may lead to additional serious complications for diabetics and other immune-compromised patients and patients with poor circulation.

The primary symptoms of onychomycosis (toenail fungus) are a toenail that turns yellow, thickens, cracks, and may separate from the nail bed


It is estimated that 35 million Americans suffer from onychomycosis. Toenail fungus can be contracted from exposure to a range of environments such as gym floors or swimming pools, which make it easy for the fungus to get under the nail and into the nail bed. Socks and shoes create a dark, warm, and moist environment for the fungus to grow.



There have been many attempts to develop remedies for toenail fungus but to date the few products FDA approved are poor treatment options largely for two reasons – topical formulations deliver low cure rates because they cannot penetrate the nail plate to reach the infected nail bed in adequate concentrations to kill the fungus, or in the case of the leading oral product terbinafine the agent must be taken daily for three months and the amount of drug in the body can lead to adverse systemic events.   The three primary treatments for onychomycosis used today are:


Lamisil® (terbinafine hydrochloride) is the most common agent used to treat toenail fungus through an ‘inside-out’ approach. Patients prescribed Lamisil take a 250mg tablet every day for 12 weeks. The medicine has to travel through the body and only a fraction of the dose reaches the toenail bed through the blood stream. The package insert confirms only 38% of people taking Lamisil achieve a complete cure and there can be drug interactions and adverse effects associated with its use. Liver toxicity is a potential side effect and for that reason patients are often required to undertake periodic lab tests to ensure that their liver is functioning properly while on the product.


Jublia®, Kerydin®, and Penlac® are topical medications brushed on the top of the toenail in an ‘outside-in’ approach to try and reach the toenail fungus in the nail bed. This route requires the medicine to penetrate through three layers of hard keratinized nail plate to reach the nail bed underneath where the fungus resides and does it’s damage. As expected, penetrating the nail plate is challenging and in formal clinical trials, the complete cure rates reported for these products ranged from only one out of five patients to as few as one out of 20 patients.  While complete cure rates are significantly lower than oral terbinafine, topicals are used mainly by mild to moderately infected patients because they do not have the liver toxicity and other drug interaction risk associated with the three oral products that are now FDA approved.

Toenail debridement

This routine podiatric procedure involves trimming, thinning, and removing as much of the fungus-infected nail and debris under the nail as possible. Podiatrists perform up to six debridement procedures per year on their patients with onychomycosis. While debridement is helpful, it does not cure the infection which means patients must continue debridement for years in an attempt to minimize pain and discomfort from their chronic onychomycosis.



Hallux is focused on subungual treatment of onychomycosis with high concentration topical terbinafine forms. The aim is to provide patients with a highly effective procedure that is safe, quick and convenient, and one that minimizes the systemic risk commonly associated with oral medications.  .

Administering this proven fungicidal drug directly to the nail bed enables delivery of terbinafine to the site of infection where it is needed. Taking the same drug orally requires much higher doses and exposure as the antifungal agent must travel throughout the body’s systemic circulation before reaching the toenail bed in tiny quantities.


Hallux has developed an innovative procedure that enables targeted, subungual delivery of terbinafine achieving higher drug concentrations at the site of infection than existing oral and topical products.


At Hallux, our approach to treating onychomycosis is to safely deliver high concentrations of topical terbinafine directly to the nail bed infection site that leads to higher cure rates. We accomplish this  ‘safety first’ approach by killing the fungus without exposing the body to oral medications. In this way, we strive to offer patients a significant improvement over existing orals and topicals by eliminating:

  • Three months of daily pills or tablets
  • Twelve months or more of daily brush-on topicals
  • The potential for systemic side-effects
  • The potential for harmful drug interactions.

The Hallux Micro-Insert HTS-519  completed a phase 2  clinical study in moderate to severe onychomycosis patients in September 2018.