In the study a single patient suffering from PC was treated with TD101 siRNA, which specifically and potently targets keratin 6a (K6a) N171K mutant mRNA without affecting wild-type K6a mRNA. Randomly assigned solutions of TD101 or vehicle control were injected into symmetric plantar calluses on the patient's opposite feet.

Results published in the November 24, 2009, online edition of the journal Molecular Therapy revealed a regression of the callus on the siRNA-treated, but not on the vehicle-treated foot. No adverse events occurred during the trial or in the 3-month washout period.

The authors stated that this trial represented the first time that siRNA had been used in a clinical setting to target a mutant gene or a genetic disorder, and was the first use of siRNA in human skin.

In addition, first author Dr. Sancy Leachman, professor of dermatology at the Huntsman Cancer Institute (Salt Lake City, UT, USA), said, "The result is exceptionally promising since it suggests that siRNAs can be used safely on the skin and also possibly to treat genetic disorders that would otherwise have few therapeutic options. The patient was treated with siRNA on her right foot and with placebo on the left foot. The callus on the right foot that received the siRNA fell off at the site of injection, but this did not happen on the left foot."

Related Links:
Huntsman Cancer Institute