Preladenant (SCH 420814) was a drug that was developed by

Schering-Plough Schering-Plough Corporation was an American pharmaceutical company. It was originally the U.S. subsidiary of the German company Schering AG, which was founded in 1851 by Ernst Christian Friedrich Schering. As a result of nationalization, it becam ...

which acted as a potent and selective

antagonist An antagonist is a character in a story who is presented as the chief foe of the protagonist. Etymology The English word antagonist comes from the Greek ἀνταγωνιστής – ''antagonistēs'', "opponent, competitor, villain, enemy, riv ...

at the

adenosine Adenosine ( symbol A) is an organic compound that occurs widely in nature in the form of diverse derivatives. The molecule consists of an adenine attached to a ribose via a β-N9-glycosidic bond. Adenosine is one of the four nucleoside building ...

A_2A receptor. It was being researched as a potential treatment for

Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...

. Positive results were reported in Phase II

clinical trials Clinical trials are prospective biomedical or behavioral research studies on human participants designed to answer specific questions about biomedical or behavioral interventions, including new treatments (such as novel vaccines, drugs, dietar ...

in humans, but it did not prove itself to be more effective than a placebo during Phase III trials, and so was discontinued in May 2013.

References

2-Furyl compounds Para-Methoxyphenylpiperazines Phenol ethers Adenosine receptor antagonists {{nervous-system-drug-stub