Therapeutic Effect of Evenamide, a Glutamate Inhibitor, in Patients With Treatment-Resistant Schizophrenia (TRS): Final, 1-Year Results From a Phase 2, Open-Label, Rater-Blinded, Randomized, International Clinical Trial.

The results from a pilot, 1-year, randomized, open-label, add-on treatment study in treatment-resistant schizophrenia (TRS) with evenamide, a glutamate modulator, were not associated with any safety abnormalities at all doses (7.5-30 mg bid), with a high retention rate even at 6-month (85%), and 1-year (75%), and the absence of psychotic relapses during the 1-year treatment period. Overall, treatment with evenamide showed a gradual, sustained, and clinically important improvement up to 1 year in all efficacy measures (eg, PANSS mean change ~ -20%; CGI-S mean change ~ -1.0). In addition, compared to the results at Week 6, the responder rates generally more than doubled at 1-year (PANSS "≥20% improvement from baseline" = ~45%; CGI-S "2-category of improvement" = ~25%; CGI-C "much improved" = ~40%). These results, rarely replicated in other trials in TRS, support the use of evenamide as an add-on treatment in patients who are not benefiting from their current first- or second-generation antipsychotic medication.