In Spite of Mixed Clinical Trial Results, NMDA Receptor Enhancers May Still Prove Useful

Although a phase-2 clinical trial reported recently in JAMA Psychiatry suggested that an NMDA receptor enhancer called bitopertin might be effective against the negative symptoms of schizophrenia, two phase-3 trials concerning bitopertin to treat negative symptoms gave disappointing results, according to the drug's manufacturer, R. Hoffmann-LaRoche Ltd. in Switzerland.

Whether bitopertin eventually turns out to be an effective drug for negative symptoms, two experts on the subject remain hopeful that NMDA receptor enhancers might prove beneficial in countering schizophrenia's negative symptoms, at least for certain patients. One is Donald Goff, M.D., a professor of psychiatry at New York University and an expert in translational schizophrenia research. The other is Serdar Dursun, M.D., Ph.D., a professor of psychiatry and neuroscience at the University of Alberta in Canada.

"It's possible that a subgroup of patients might benefit from these agents, but Roche wasn't able to identify a biomarker that would predict response," Goff said in an interview. And as Dursun told Psychiatric News, "There must be improved clinical-trial methods that include identification of biomarkers so as to reduce the patient heterogeneity problem in schizophrenia."

For more about research into the use NMDA receptor enhancers to treat negative symptoms, see the Psychiatric News article "Surprising Drug Improves Schizophrenia Symptoms."

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