NEW YORK (GenomeWeb) – Tekmira Pharmaceuticals this week announced that it has completed the single ascending dose portion of a Phase I trial of its RNAi-based Ebola treatment TKM-Ebola, with treatment proving to be well tolerated up to .3 mg/kg.
Based on the results, Tekmira said it will initiate the multiple ascending dose portion of the trial next month.
TKM-Ebola is being developed under a contract from the US Department of Defense that could be worth up to $140 million and fund the drug's development through to commercialization. Tekmira had previously tested an earlier version in phase I, but cut that trial short in order to incorporate improvements to its lipid nanoparticle delivery vehicles.
Late last year, the company was cleared to start testing the next-generation version of the drug in healthy volunteers in the two-part Phase I study. According to Tekmira, a total of 19 individuals were enrolled in the single ascending dose arm of that trial, which tested doses ranging from .075 mg/kg to .5 mg/kg.
Adverse events were observed at all dose levels, including a dose-limiting toxicity in those receiving the highest dose of TKM-Ebola. Most of these were consistent with a transient inflammatory response that typically begins shortly after treatment and ends 24 hours after dosing.
Notably, no study subjects received pre-medication to address immune responses associated with siRNAs, something that Tekmira has done in other clinical studies and indicated it would not include in the upcoming multiple ascending dose portion of the TKM-Ebola Phase I trial.
An analysis of drug exposure in the single-dose arm of the study indicated that a dose of .24 mg/kg/day will meet the exposure targets derived from the highest dose level used in non-human primate efficacy testing, which showed complete protection from Ebola at .5 mg/kg, Tekmira said.
The company added that it plans to treat subjects in the multiple ascending dose arm of the Phase I trial at the maximum tolerated dose of .3 mg/kg. Specifically, that part of the study will enroll up to 12 healthy individuals who will receive daily doses of TKM-Ebola of either .6 mg/kg, .12 mg/kg, or .24 mg/kg.