Xenon Pharmaceuticals has initiated a Phase II clinical trial of its topical XEN402 therapy, a potential treatment for post-herpetic neuralgia.

XEN402’s Phase I study showed that the product was well-tolerated by patients and achieved good concentrations in the skin.

The treatment targets the sodium channel sub-type Nav1.7, which is highly expressed in sensory nerve endings, to treat the pain involved in post-herpetic neuralgia.

Xenon President and CEO Dr. Simon Pimstone said that XEN402 was built on the company’s genetic studies, which showed Nav1.7 deficient humans are completely unable to feel pain.

“Our pre-clinical data show excellent efficacy with topical XEN402 in multiple inflammatory and neuropathic pain models when compared to other topical agents and oral pain treatments,” Pimstone said.

Xenon plans to conclude the Phase II trial in the first quarter of 2011, with top-line data available in the following quarter.