SB208 - Fungal Skin Infections

Novan is developing SB208 as a broad-spectrum antifungal gel for the treatment of superficial cutaneous fungal infections of the skin and nails, such as tinea pedis and onychomycosis. Recent studies suggest that both the nail plate, interdigital space and surrounding cutaneous tissue may serve as an overlooked reservoir of dermatophytes, perpetuating reinfection and coinfection of onychomycosis and tinea pedis. Additionally, studies have demonstrated enhanced efficacy when tinea pedis and onychomycosis are treated concurrently, suggesting that an effective topical treatment, suitable for simultaneous application to the nail plate and skin, may lead to lower rates of recurrence and enhanced efficacy.

Clinical Trial Results

In a Phase 2 clinical trial enrolling 200 patients with tinea pedis, or athlete’s foot, SB208 demonstrated a statistically significant effect (p<0.05) compared to vehicle in reducing dermatophytes that cause these fungal infections.

  • In the primary efficacy analysis of patients with evaluable culture results, 80.6% (p=0.002) of patients treated with SB208 4% and 74.2% (p=0.016) of patients treated with SB208 16% achieved negative fungal culture at day 14 versus 45.5% of patients treated with vehicle.
  • The percentage of patients achieving mycological cure at the day 14 visit was 50.0% (p=0.009) of the patients treated with SB208 4% and 53.1% (p=0.010) of patients treated with SB208 16% versus 23.5% of patients treated with vehicle. Mycological cure is defined by having a negative laboratory culture and negative fungal clinical diagnosis.
    • At the end of a 4-week post treatment follow-up period, mycological cure was maintained at day 42 in both dose groups; 58.8% of patients treated with SB208 16% demonstrated a mycological cure compared to vehicle (p<0.05).

Preclinical Data

In the ChubTur® infected human nail assay, a model utilized previously in the drug development of Kerydin® (tavaborole) Topical Solution, 5%, and Jublia® (efinaconazole) Topical Solution, 10%, nitric oxide-releasing formulations including SB208 demonstrated rapid penetration of the nail and effective fungal killing of Trichophyton rubrum in 24 hours following a single treatment application.

Click here to view the poster presented at ASM Microbe 2016.

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About Onychomycosis

Onychomycosis is a chronic fungal infection of the nails that affects approximately 40 million Americans and accounts for one-third of cutaneous fungal infections. The prevalence of disease increases with age, and more than 50% of patients are 70 years or older. The infection, caused by dermatophytes such as Trichophyton rubrum, often results in painful thickening and deformation of the nail and sometimes the separation of the nail plate from the nail bed, leading to an inability of the nail to perform its natural protective function. Oral therapies used to treat the infection are associated with severe side effects, and topical therapies have modest efficacy profiles with complete cure rates of less than 20%.

About Tinea Pedis

Tinea pedis, often referred to as Athlete’s Foot, is a common fungal infection of the feet, affecting approximately 75 million Americans. Trichophyton rubrum is the most prominent dermatophyte in tinea pedis and also a causative pathogen in onychomycosis. Approximately one-third of onychomycosis patients also suffer from tinea pedis. Topical treatments are the first-line therapy for tinea pedis, while oral antifungals are prescribed when the infection is severe or the use of topical antifungals is not feasible. Currently, there is no approved single topical therapeutic agent that provides for the simultaneous treatment of the nail plate, bed, and surrounding cutaneous tissue.