SV156

SV156 is a small molecule, selective D2 dopamine receptor antagonist that was investigated for the treatment of L-dopa-induced dyskinesia (LID) in Parkinson's Disease. It belongs to a series of substituted phenylpiperazine compounds and demonstrates approximately 40-fold binding selectivity for the D2 receptor subtype over the D3 receptor. Pharmacologically, SV156 acts as a neutral antagonist with no detectable intrinsic activity (agonist or partial agonist) at the D2 receptor. In preclinical studies using 6-hydroxydopamine (6-OHDA) unilaterally lesioned rat models, SV156 showed only marginal efficacy in reducing abnormal involuntary movements (AIMs) and was associated with neuroleptic-like side effects, such as reduced mobility and flat posture, at higher doses. Consequently, development for this indication was not prioritized in favor of D3-selective candidates.