US-based ContraVir Pharmaceuticals has started a pharmacokinetic (PK) trial of its clinical-stage, fast acting, low dose, once-daily oral antiviral agent FV-100 to treat herpes zoster or shingles, an infection caused by the reactivation of varicella zoster virus.

Scheduled to be conducted at Duke University in early 2015, the PK trial is designed to further understand the effect of a potent inhibitor of Cytochrome P450 3A4 on the pharmacokinetics of FV-100.

The trial will allow the company to better understand the potential for clinically important drug-drug interactions as well as further optimise treatment for Phase III development.

“We look forward to reporting the results of this study in 2015, and to accelerating our plans to begin dosing shingles patients in the next clinical efficacy trial.”

In addition to direct antiviral activity, FV-100 has showed the potential to reduce the incidence of debilitating shingles-associated pain, known as post-herpetic neuralgia (PHN).

ContraVir chief executive officer James Sapirstein said: “Initiation of this PK study strongly aligns with our goal of optimising the treatment regimen for FV-100.

“We look forward to reporting the results of this study in 2015, and to accelerating our plans to begin dosing shingles patients in the next clinical efficacy trial.”

Apart from the current PK trial, the company has completed planning a larger clinical study of FV-100 to confirm the previous favourable efficacy and safety results.

The new trial is designed to measure the efficacy of FV-100 for treating shingles and associated PHN, as measured by the incidence of clinically meaningful pain at the end of the follow-up period, as well as determine the best dose and regimen of treatment.

According to the preclinical studies, FV-100 is more potent against VZV than acyclovir, famcyclovir, and valacyclovir, the FDA approved drug for treating shingles.

Additionally, FV-100 has been shown to have a more rapid onset of antiviral activity in preclinical models.