Hallux is a clinical-stage pharmaceutical company focused on developing a new dosage form and route of administration for treating onychomycosis (toenail fungus) patients. To date, treatments for toenail fungus have been either topical products that have difficulty reaching the site of infection, or oral products that have systemic safety issues.

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

The company’s flagship product, the HTS-519 Micro-Insert, is biodegradable and delivers high concentrations of terbinafine hydrochloride 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 is currently in phase 2 clinical trials with this breakthrough product for toenail fungus.



Onychomycosis is a fungal infection of the nail bed and plate that primarily involves the toenails. It is commonly referred to as ‘toenail fungus’ as toenail infections constitute about 80% 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 toenail bed takes over, the damage to the nails 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 approaches to treating toenail fungus but all have been only marginally successful for two reasons – they cannot penetrate the nail plate and reach the site of infection in the nail bed at the concentrations needed to kill the fungus effectively, or the amount of drug in the body can lead to adverse events.   The three primary treatments for onychomycosis used today are:


Lamisil® (terbinafine) is a common drug used to treat toenail fungus through an ‘inside-out’ approach. Patients prescribed Lamisil take a pill once per day for 12 weeks. The drug releases through the body and only a fraction of the drug reaches the targeted nail bed via the bloodstream. Published data reports that only 38% of patients on Lamisil achieve a complete cure and there are rare cases of liver toxicity and other systemic side effects associated with its use when taken orally.


Jublia®, Kerydin®, and Penlac® are topical medications that are applied on top of the toenail in an ‘outside-in’ approach in an attempt to reach the fungus in the nail bed. This means that the applied medication has to travel through the hard nail plate to get to the nail bed underneath and treat the fungus. As expected, penetrating the nail plate is difficult 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.  Complete cure rates are lower than oral medication but do not have the liver toxicity and other drug interactions associated with taking a pill once-per-day for 12 weeks.

Toenail debridement

This 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 is not a cure.



Hallux is focused on localized treatment of onychomycosis with its novel, biodegradeable Micro-Insert, HTS-519.

This direct-to-the nail bed approach is designed to be highly effective without exposing patients to the systemic risks of orals or the compliance burden of once-daily self-application of topical products for twelve months.

The in-office procedure involves a physician administering HTS-519 subungually (‘under the nail’) of the infected Great Toe resulting in direct delivery of fungus-killing terbinafine to the site of infection.


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.


Our subungual treatment approach aims to safely deliver high concentrations of the market leading anti-fungal drug directly to the nail bed. We accomplish our ‘safety first’ approach by killing the fungus without exposing the body to orally administered drugs. In this way, we strive to offer patients an alternative to existing therapies thus eliminating:

  • Three months of daily pill or tablet therapy
  • The need for monthly liver function tests
  • The potential for systemic side effects
  • The low cure rates and year-long treatment regimens associated with topicals

The Hallux Micro-Insert is in clinical studies and not FDA approved in the United States.