Cutaneous nerve fiber and peripheral Nav1.7 assessment in a large cohort of patients with postherpetic neuralgia.

"Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article."

"This study and the clinical trial from which these data were obtained were funded by exclusively by Teva Pharmaceuticals. M. Fetell, T. Li, and L. Marinelli are employees of Teva. F. L. Rice, P. J. Albrecht, E. Ruggerio, G. Houk, and M. Dockum are employees of INTiDYN, which was contracted and paid to collect and analyze the skin biopsies. R. Baron, M. Sendel, and J. Vollert were not compensated for their work."

"This report is based on a retrospective analysis of a phase 2, randomized, double-blind, placebo-controlled, parallel-group study to evaluate the safety and efficacy of topically applied TV-45070 (4% and 8% wt/wt ointment) in patients with PHN. Male and female individuals aged 18 to 80 years, less than 10 years after the appearance of herpes zoster rash, with a clinical diagnosis of persistent PHN pain for >6 months, and an average daily pain score of ≥4 on the 11-point numerical rating scale (NRS), who also had intact skin over the treatment area were eligible for inclusion. Postherpetic neuralgia affecting trigeminal dermatomes was exclusionary. Verification of the initial acute herpetic infection or if the medical history could not be obtained, evidence of treatment with antivirals for an acute painful rash was required. Patients were genotyped by Q2 Solutions (a division of Quest Labs; Valencia, CA) for the rs6746030 allele, a gain of function, single-nucleotide polymorphism of the SCN9A gene, which codes for Nav1.7, that has been linked to slower Nav1.7 channel inactivation and lower pain thresholds. The polymorphism A allele contains a substitution of tryptophan for arginine at position 1150 of Nav1.7 (R1150W); G denotes the common allele. The phase 2 study (TV-45070-CNS-20013) was sponsored by Teva Pharmaceuticals, conducted in collaboration with Xenon Pharmaceuticals, and registered on clinicaltrials.gov (NCT02365636). The study was approved by a central ethics committee, performed exclusively in the United States in full accordance with ICH, GCP, and all applicable national and local laws and regulations, and subjects provided informed consent."