Phase 2 Results Indicate Evenamide, A Selective Modulator of Glutamate Release, Is Associated With Clinically Important Long-Term Efficacy When Added to an Antipsychotic in Patients With Treatment-Resistant Schizophrenia.

Results from a pilot, 6-week, randomized, open-label, rater-blinded study, with 46-week extension, indicate very good tolerability with exceptional, clinically important, increasing efficacy of evenamide (7.5, 15, and 30 mg bid), a glutamate modulator, as add-on treatment to antipsychotics in 161 treatment-resistant, schizophrenia patients. Ninety-five percent of patients completed 6 weeks (1 discontinued for adverse event), and 89% continued in the extension. Results from the first 100 patients enrolled showed very low attrition over 1 year (77 completers); data pooled from all dose groups showed the Positive and Negative Syndrome Scale total score improved significantly (P < .001; paired t test; last observation carried forward [LOCF]) from baseline at 6 weeks (-9.4), 6 months (-12.7), and 1 year (-14.7); similarly, the proportion of responders (≥20% improvement) increased over time from 6 weeks (16.5%) to 6 months (39%) to 1 year (47.4%). Noteworthy improvement was also observed at each timepoint on the Clinical Global Impression - Severity scale and Clinical Global Impression of Change, indicating progressively increasing efficacy of evenamide up to 1 year.