Bitopertin (developmental code names RG1678; RO-4917838) is a

glycine reuptake inhibitor A glycine reuptake inhibitor (GRI) is a type of drug which inhibits the reuptake of the neurotransmitter glycine by blocking one or more of the glycine transporters (GlyTs). Examples of GRIs include bitopertin (RG1678), Org 24598, Org 25935, AL ...

which was under development by

Roche F. Hoffmann-La Roche AG, commonly known as Roche, is a Swiss multinational healthcare company that operates worldwide under two divisions: Pharmaceuticals and Diagnostics. Its holding company, Roche Holding AG, has shares listed on the SIX S ...

as an adjunct to

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

s for the treatment of persistent

negative symptoms Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showin ...

or suboptimally controlled

positive symptoms Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showin ...

associated with

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 withdra ...

. Research into this indication has been largely halted as a result of disappointing trial results. Bitopertin is a

glycine transporter 1 Sodium- and chloride-dependent glycine transporter 1, also known as glycine transporter 1, is a protein that in humans is encoded by the ''SLC6A9'' gene. Selective inhibitors Elevation of extracellular synaptic glycine concentration by blockade of ...

(GlyT1) inhibitor that increases levels of the

neurotransmitter A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a synapse. The cell receiving the signal, any main body part or target cell, may be another neuron, but could also be a gland or muscle cell. Neuro ...

glycine Glycine (symbol Gly or G; ) is an amino acid that has a single hydrogen atom as its side chain. It is the simplest stable amino acid (carbamic acid is unstable), with the chemical formula NH2‐ CH2‐ COOH. Glycine is one of the proteinogeni ...

by inhibiting its

reuptake Reuptake is the reabsorption of a neurotransmitter by a neurotransmitter transporter located along the plasma membrane of an axon terminal (i.e., the pre-synaptic neuron at a synapse) or glial cell after it has performed its function of transm ...

from the

synaptic cleft Chemical synapses are biological junctions through which neurons' signals can be sent to each other and to non-neuronal cells such as those in muscles or glands. Chemical synapses allow neurons to form circuits within the central nervous syste ...

. Glycine acts as a required

co-agonist An agonist is a chemical that activates a receptor to produce a biological response. Receptors are cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an antagonist blocks the action of the agoni ...

along with

glutamate Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can syn ...

at ''N''-methyl-D-aspartate (NMDA)

receptors Receptor may refer to: *Sensory receptor, in physiology, any structure which, on receiving environmental stimuli, produces an informative nerve impulse *Receptor (biochemistry), in biochemistry, a protein molecule that receives and responds to a n ...

. Dysfunction of NMDA receptors may play a key role in the pathogenesis of schizophrenia and modulation of

glutamatergic Glutamatergic means "related to glutamate". A glutamatergic agent (or drug) is a chemical that directly modulates the excitatory amino acid (glutamate/ aspartate) system in the body or brain. Examples include excitatory amino acid receptor agonist ...

signalling via increased concentrations of glycine in the synaptic cleft may help potentiate NMDA receptor function and improve the symptoms of schizophrenia."Bitopertin for schizophrenia"
, "EuroScan", 14 August 2012 In a phase II proof-of-concept study, patients on bitopertin experienced a significant improvement in the change of the Negative Symptom Factor Score from baseline within 8 weeks (from −4.86 in the placebo group to −6.65 in the treatment group, p<0.05, per-protocol population). In addition, 83% of patients on bitopertin described an improvement of negative symptoms on the CGI-I1 versus 66% on placebo (p<0.05, per-protocol population).Glycine Transporter Type 1 (GLYT1) Inhibitor RG1678: Positive Results of the Proof-of-Concept Study for the Treatment of Negative Symptoms in Schizophrenia, Umbricht D. et al., ACNP 2010 In January 2014, Roche reported that bitopertin failed to meet its endpoints in two phase III trials assessing its efficacy in reducing negative symptoms of schizophrenia. Subsequently, in April 2014, Roche announced that it was discontinuing all except one of its phase III trials of bitopertin for schizophrenia.

References

{{Glycine receptor modulators Experimental drugs Glycine reuptake inhibitors N-benzoylpiperazines Trifluoromethyl compounds Benzosulfones Organofluorides

See also

References