Prana Biotechnology (PRAN)

[interestingtome]

Lon Schneider comments on REACH2HD trial

I think the insight into the Trail Making Part B tests is valuable.

Lon Schneider
University of Southern California Keck School of Medicine
Posted: 21 Feb 2014

In this small Phase 2 trial of only 109 patients the sponsor's safety objectives were met, and there appears to be no regulatory barrier to going forward to Phase 3 and assessing PBT2 for efficacy. The trial wasn't intended as an efficacy trial and shouldn't be interpreted as one; indeed, none was found, nor should efficacy have been expected.

Of eight neuropsychological tests, only Trails B was reported as significant. Of three composites of some of these eight tests, only the executive-function composite, which included category fluency and Trails B, was statistically significant. There was no effect on motor function, behavior, two functional-ability scales, two global assessments, biomarkers, or imaging that favored PBT2—again, as would be expected.

So only the time for the Trails B test of about 20 possible outcomes and biomarkers was significant. The effect here was that for people on the 250 mg dose, time to complete the test didn't change, while for those on the lower dose and placebo, the time worsened by 15 seconds. That’s quite a big mean change. It would be most interesting to see the mean baseline times and standard deviations for the Trails B for each treatment group and the distribution of the change scores, as these data would help with interpreting any meaning to the p value reported.