Background: Mibampator, an amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor potentiator, was evaluated for treatment of agitation and aggression (A/A) in Alzheimer's disease (AD).

Methods: Outpatients (n = 132) with probable AD and A/A randomized to 12 weeks of double-blind treatment with 3-mg po mibampator or placebo were assessed using the 4-domain A/A subscale of the Neuropsychiatric Inventory (NPI-4-A/A) derived from the Neuropsychiatric Inventory. Secondary measures included the Cohen-Mansfield Agitation Inventory, Cornell Scale for Depression in Dementia, Frontal Systems Behavior Inventory (FrSBe), and Alzheimer's Disease Assessment Scale-Cognitive. Efficacy was analyzed using mixed-effects model repeated measures from baseline to endpoint. Adverse events (AEs), labs, vital signs, and electrocardiograms were monitored.

Results: Baseline characteristics were comparable between groups. Both groups improved on the NPI-4-A/A, but without group differences. Among secondaries, mibampator was significantly better (p = 0.007) than placebo only on the FrSBe. AEs were similar between groups. One death occurred in the placebo group.

Conclusion: Possible explanations for no significant group differences include caregiver, drug target engagement, and design issues.

This trial is registered on ClinicalTrials.gov; ID: NCT00843518.