Mardepodect (developmental code name PF-2545920) is a drug which was developed by

Pfizer Pfizer Inc. ( ) is an American multinational pharmaceutical and biotechnology corporation headquartered on 42nd Street in Manhattan, New York City. The company was established in 1849 in New York by two German entrepreneurs, Charles Pfizer ...

for the treatment of

schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social wit ...

. It acts as a

phosphodiesterase inhibitor A phosphodiesterase inhibitor is a drug that blocks one or more of the five subtypes of the enzyme phosphodiesterase (PDE), thereby preventing the inactivation of the intracellular second messengers, cyclic adenosine monophosphate (cAMP) and cyc ...

selective for the PDE_10A subtype. The PDE_10A enzyme is expressed primarily in the brain, mostly in the striatum,

nucleus accumbens The nucleus accumbens (NAc or NAcc; also known as the accumbens nucleus, or formerly as the ''nucleus accumbens septi'', Latin for " nucleus adjacent to the septum") is a region in the basal forebrain rostral to the preoptic area of the hypot ...

and

olfactory tubercle The olfactory tubercle (OT), also known as the tuberculum olfactorium, is a multi-sensory processing center that is contained within the olfactory cortex and ventral striatum and plays a role in reward cognition. The OT has also been shown to ...

, and is thought to be particularly important in regulating the activity of dopamine-sensitive medium spiny neurons in the striatum which are known to be targets of conventional

antipsychotic Antipsychotics, also known as neuroleptics, are a class of psychotropic medication primarily used to manage psychosis (including delusions, hallucinations, paranoia or disordered thought), principally in schizophrenia but also in a range of ...

drugs. Older PDE_10A inhibitors such as

papaverine Papaverine (Latin '' papaver'', "poppy") is an opium alkaloid antispasmodic drug, used primarily in the treatment of visceral spasms and vasospasms (especially those involving the intestines, heart, or brain), occasionally in the treatment of e ...

have been shown to produce antipsychotic effects in animal models, and more potent and selective PDE_10A inhibitors are a current area of research for novel antipsychotic drugs which act through a different pathway to conventional dopamine or 5-HT_2A antagonist drugs and may have a more favourable side effects profile. Mardepodect is currently one of the furthest advanced PDE_10A inhibitors in development and has progressed through to Phase II clinical trials in humans. In 2017, development of mardepodect for the treatment of schizophrenia and

Huntington's disease Huntington's disease (HD), also known as Huntington's chorea, is a neurodegenerative disease that is mostly inherited. The earliest symptoms are often subtle problems with mood or mental abilities. A general lack of coordination and an uns ...

was discontinued.

References

{{Phosphodiesterase inhibitors Abandoned drugs Pfizer brands Phenol ethers Phosphodiesterase inhibitors Pyrazoles 4-Pyridyl compounds Quinolines