NCT04624243

Efficacy and Safety of MK-8189 in Participants With an Acute Episode of Schizophrenia (MK-8189-008)

A Phase 2B Randomized, Double-Blind, Placebo- and Active-Controlled Trial of the Efficacy and Safety of MK-8189 in Participants Experiencing an Acute Episode of Schizophrenia

• Status: Completed
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 499 (actual)
• Sponsor: Merck Sharp & Dohme LLC · Industry
• Sex: All
• Age: 18 Years – 55 Years
• Healthy volunteers: Not accepted

Summary

The purpose of this study was to evaluate the efficacy and safety of MK-8189 at a range of doses (8 mg, 16 mg, and 24 mg once daily \[QD\]) in adult participants who have an acute episode of schizophrenia according to Diagnostic and Statistical Manual of Mental Disorders 5th Edition (DSM-5) criteria. The primary hypotheses were the following: (1) that MK-8189 24 mg is superior to placebo in reducing the Week 6 mean change from baseline in Positive and Negative Syndrome Scale (PANSS) total score, and (2) that MK-8189 16 mg is superior to placebo in reducing the Week 6 mean change from baseline in PANSS total score. With Amendment 4, enrollment was changed to approximately 500 participants with removal of the MK-8189 8 mg treatment arm. Participants enrolled before Amendment 4 who were assigned to MK-8189 8 mg QD remained on that dose regimen per protocol.

Conditions

• Schizophrenia

Interventions

Type	Name	Description
DRUG	MK-8189	MK-8189 administered QD at a dose of 8 mg, 16 mg, or 24 mg via oral tablet.
DRUG	Risperidone	Risperidone administered QD at a dose of 6 mg via oral capsule.
DRUG	Placebo to MK-8189	MK-8189-matching placebo administered QD via oral tablet.
DRUG	Placebo to risperidone	Risperidone-matching placebo administered QD via oral capsule.

Timeline

• Start date: 2020-12-15
• Primary completion: 2024-06-21
• Completion: 2024-06-21
• First posted: 2020-11-10
• Last updated: 2026-02-05
• Results posted: 2025-08-22

Locations

121 sites across 12 countries: United States, Bulgaria, Croatia, Japan, Latvia, Poland, Romania, Russia, Serbia, South Korea, Taiwan, Ukraine

Regulatory

• FDA-regulated drug study