TransDerm, a small biotech focused on developing a treatment for pachyonychia congenita (PC), has just kicked off a phase I trial of a new drug candidate designed to treat the rare skin condition.
However, while the company had been focused on using RNAi as foundation for its products, the new trial is testing a product based on sirolimus, a macrolide immunosuppressant commonly used to prevent organ rejection in transplant patients.
TransDerm's first candidate, the siRNA-based drug TD101, proved capable of treating the lesions caused by PC in a single-patient phase I trial in 2008, but administration of the therapy — injection via a standard hypodermic needle — proved too painful to make the approach viable.
TransDerm began developing a microneedle array that could deliver TD101 without the pain and had been planning to begin testing it in another clinical study. However, it appears that the company has opted to pursue a different therapeutic modality for its next clinical candidate in sirolimus, which is topically administered.
It is unclear why TransDerm has put its TD101 efforts on hold, and company officials were unavailable for comment. However, the agent was designed to target a specific genetic mutation that is only present in a fraction of PC patients — a limit to its use that may have prompted the move to a compound with a potentially broader spectrum of activity.