Concert Pharmaceuticals has launched a Phase I clinical trial to assess CTP-692 as an adjunctive therapy for schizophrenia.

CTP-692 is a deuterium-modified form of endogenous D-serine that is believed to work by restoring NMDA receptor activity in some parts of the brain.

The therapeutic is intended to be used as an adjunctive therapy to standard antipsychotic drugs for addressing positive and negative symptoms, and also cognitive function in schizophrenic patients.

During the Phase I trial, the safety, tolerability and pharmacokinetic profile of multiple ascending doses of CTP-692 will be evaluated over seven days in healthy volunteers.

The double-blind, placebo-controlled trial is part of the company’s Phase I programme to investigate the drug candidate in a total of 80 participants.

“The Phase I studies evaluating the dosing and safety of CTP-692 are expected to support advancement into an efficacy study.”

Apart from the newly launched trial, the programme comprises a crossover study to compare CTP-692 with D-serine and a single-ascending dose trial to monitor the effects of food on pharmacokinetics.

In the crossover study, CTP-692 was observed to have improved plasma exposure compared to D-serine. It was also well-tolerated, with no serious adverse events recorded.

Top-line results from the trials are expected to be available in the second quarter of this year.

Concert Pharmaceuticals president and CEO Roger Tung said: “The Phase I studies evaluating the dosing and safety of CTP-692 are expected to support advancement into an efficacy study in patients with schizophrenia later this year.

“CTP-692 represents the fastest moving programme in our pipeline to date, demonstrating our team’s ability to rapidly identify and pursue compelling new therapeutic opportunities based on Concert’s deuterium chemistry platform.”

In preclinical studies, CTP-692 demonstrated the potential to improve upon the safety profile of D-serine, which was linked to nephrotoxicity in other published preclinical findings.

The company’s studies have revealed that selective modification of deuterium led to enhanced CTP-692 exposure relative to a similar D-serine dose.

Furthermore, CTP-692 was not associated with changes in serum creatinine and blood urea nitrogen when administered at doses where D-serine resulted in significant nephrotoxicity as assessed by these markers of kidney function.