Canada-based developer of RNA interference (RNAi) therapeutics, Tekmira Pharmaceuticals, has received notice from the US Food and Drug Administration (FDA) that the TKM-Ebola Phase I healthy volunteer clinical trial has been placed on clinical hold.
The company said that FDA notice applies only to this randomised, single-blind, placebo-controlled TKM-Ebola Phase I trial.
The TKM-Ebola Phase I trial involves single ascending doses and multiple ascending doses of TKM-Ebola.
The trial is designed to evaluate safety, tolerability and pharmacokinetics of administering TKM-Ebola to healthy adult volunteers without administering any steroid pre-medications.
Tekmira Pharmaceuticals president and CEO Mark Murray said: "The FDA has requested additional data related to the mechanism of cytokine release, observed at higher doses, which we believe is well understood, and a protocol modification designed to ensure the safety of healthy volunteer subjects, before we proceed with the multiple ascending dose portion of our TKM-Ebola Phase I trial.
"We will continue our dialogue with the FDA, provided for under our fast track status, in order to advance the development of this important therapeutic agent."
TKM-Ebola is an anti-Ebola virus RNAi therapeutic and is currently being developed under a $140 contract with the US Department of Defense's Medical Countermeasure Systems BioDefense Therapeutics (MCS-BDTX) Joint Product Management Office.
Earlier preclinical studies have shown that when siRNA targeting the Ebola virus and delivered by Tekmira's LNP technology were used to treat previously infected non-human primates, the result was 100% protection from an otherwise lethal dose of Zaire Ebola virus.
Tekmira received the FDA fast track status in March 2014 for the development of TKM-Ebola.