US-based Viamet Pharmaceuticals has started a Phase IIb clinical trial (RENOVATE) of VT-1161, a novel, orally-available, highly potent and selective inhibitor of fungal CYP51, to treat toenail onychomycosis.

In an earlier Phase IIa proof-of-concept trial, VT-1161 showed robust antifungal activity and a very favourable safety profile in the treatment of tinea pedis.

Around 250 patients with toenail onychomycosis at about 25 clinical sites throughout the US will be enrolled in the randomised, double-blind, placebo-controlled RENOVATE trial.

The trial is designed to assess two dose levels of VT-1161 administered once weekly for either ten or 22 weeks following an initial two-week loading dose period.

Viamet CEO Robert Schotzinger said: "We are pleased to initiate the RENOVATE clinical trial and to report the positive nail and skin penetration data from our Phase IIa tinea pedis study.

"The high degree of penetration of VT-1161 into the skin and nail observed in the Phase IIa study significantly increases our confidence that the RENOVATE study in onychomycosis will be successful.

"We look forward to advancing VT-1161 in this indication, for which current oral agents are suboptimal with respect to safety and current topical agents are suboptimal with respect to efficacy."

The trial’s primary endpoint will be the percentage of patients achieving complete cure of the target nail at week 48, which extends either 24 or 36 weeks beyond the conclusion of dosing with VT-1161 depending on the dose group.

In the US, about 32 million individuals are affected by onychomycosis, a chronic fungal infection that can cause deformation, discoloration, thickening and splitting of the nail, as well as separation of the nail from the nail bed.

The company said that in in-vitro and in-vivo studies, VT-1161 has showed broad spectrum activity against both Candida species and dermatophytes, including those species that cause recurrent vulvovaginal candidiasis (RVVC) and onychomycosis.

Image: A toenail affected by onychomycosis. Photo: courtesy of Medguy.