Australia-based Prana Biotechnology has reported that its Reach2HD Phase II clinical trial investigating PBT2 as a treatment for Huntington disease succeeded in meeting the primary endpoint of the study.
The trial met its primary safety endpoint and achieved statistically significant improvement in a measure of executive function (cognition), which comprised part of the trial's main efficacy outcome.
The Huntington Study Group carried out the double-blind, placebo-controlled trial at research sites in the US and Australia.
A total of 109 individuals with Huntington disease were enrolled in the trial who were randomly assigned to receive daily doses of either PBT2 250mg, PBT2 100mg, or placebo for 26 weeks.
Of the participants, 95% (104 of 109) completed the trial on their assigned dose and there were no substantial differences in adverse events across the two PBT2 dose groups and the placebo group.
Prana chief scientific advisor and Harvard Medical School neurology professor Rudy Tanzi said: "In my opinion, these findings significantly elevate the potential for PBT2 as an effective therapy for both Huntington's disease and Alzheimer's disease."
The company said that only one of the ten reported serious adverse events was deemed by the clinical site investigator to be related to drug treatment.
The effects of PBT2 were tested on cognition, motor performance, behaviour and functional capacity, of which cognition was pre-specified as the main efficacy outcome.
There was a statistically significant improvement in performance on the Trail Making Test Part B in the PBT2 250mg group compared with placebo at both 12 and 26 weeks.
Since data from an earlier trial showed PBT2 improved executive function in Alzheimer's disease patients, the Reach2HD trial included a plan to evaluate the effects of PBT2 on an Executive Function Composite z-score that included the Trail Making Test Part B.
The company said that there was a significant improvement in the z-score in a pre-specified analysis of Reach2HD participants with early stage Huntington disease, as measured by their Total Functioning Capacity score.
It plans to advance PBT2 into a confirmatory Phase III clinical study that could allow PBT2 to be approved for the treatment of Huntington's disease.