This study evaluates the safety, biomarkers, and efficacy trends of different dose levels of investigational drug tominersen in people aged 25 to 50 with prodromal (very early subtle signs of HD) or early manifest HD. Tominersen is an investigational drug that has been studied in several clinical trials since 2015, including in a Phase III study called GENERATION HD1 that tested two different dose regimens of tominersen in adults with manifest HD.

The new Phase II of the GENERATION HD2 trial is a ‘placebo-controlled’ clinical trial, which means that one of the groups will be given a substance with no active ingredients (also known as a ‘placebo’); it looks like the drug being tested but does not contain any real medicine. Comparing results from the different groups helps the researchers know whether any changes seen result from the drug or occur by chance.

This is a double-blinded trial, which means that neither the participant nor the clinical trial doctor can choose or know the group the participant is in until the trial is over. This approach helps to prevent bias. However, the participant’s clinical trial doctor can find out which group the participant is in, if their safety is at risk.