Pridopidine works by binding and activating an intracellular protein called the Sigma-1 receptor (S1R) located at the mitochondria-associated membrane (MAM) of the endoplasmic reticulum (ER).

Following onset, motor, cognitive and functional outcomes steadily decline over 15 to 20 years, ultimately leading to a state of profound incapacity and death.

[16][17] A meta-analysis of four randomized controlled trials (RCTs) involving 1,130 patients (816 in the pridopidine group and 314 in the placebo group) found that pridopidine led to a slight, though not statistically significant, improvement in overall motor symptoms, as measured by the Unified Huntington's Disease Rating Scale Total Motor Score, compared to placebo.

The findings suggest that pridopidine has potential for treating motor symptoms in HD, with a favorable safety profile, warranting further clinical trials to confirm its benefits.

Over time this progressive loss of motor function leads to losing the ability to speak, eat, move and eventually breathe.