Aplindore is a drug which acts as a partial agonist

Partial agonist

Partial agonists bind and activate a given receptor, but have only partial efficacy at the receptor relative to a full agonist...

 selective for the dopamine receptor D2

Dopamine receptor D2

Dopamine receptor D2, also known as D2R, is a protein that, in humans, is encoded by the DRD2 gene.- Function :This gene encodes the D2 subtype of the dopamine receptor. This G protein-coupled receptor inhibits adenylyl cyclase activity...

. It is being developed by the pharmaceutical company Neurogen as a treatment for Parkinson's disease

Parkinson's disease

Parkinson's disease is a degenerative disorder of the central nervous system...

 and restless legs syndrome

Restless legs syndrome

Restless legs syndrome or Willis-Ekbom disease is a neurological disorder characterized by an irresistible urge to move one's body to stop uncomfortable or odd sensations. It most commonly affects the legs, but can affect the arms, torso, and even phantom limbs...

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On December 23rd Neurogen was acquired by Ligand Pharmaceuticals. Rights to Aplindore were given to Ligand around time of merger. As of 2008, Phase II was completed and Ligand is currently seeking a third party to bring this development of the drug into Phase III development.