As explained by Ionis officials in an e-mail, post-hoc means that Ionis did not predefine the analyses in the clinical trial protocol. Such analyses cannot provide conclusive proof of a drug effect. These analyses are common in early-stage clinical trials, where drug companies look for interesting signals worthy of careful evaluation in later-stage trials.
In fact, they added, the trial planners included the clinical tests primarily to monitor for unexpected worsening.
The Ionis officials described the relationship between mHTT-lowering and potential clinical benefit as "subtle."
They emphasized the need for larger and longer trials to demonstrate efficacy.
A 'hint of clinical benefits'
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For additional coverage of the Ionis news, click here and here.
For background on the development of clinical tests for HD, click here.
(This article was updated on April 27, 2018, to include additional comments on the clinical trial analyses by Ionis officials.)