SchizophreniaPhase 1TQTNCT05893862

A Study To Evaluate The Effect Of A Supratherapeutic Dose Of Elpipodect (MK-8189) On The QTc Interval In Participants With Schizophrenia (MK-8189-019)

A Phase 1 study testing Elpipodect and Moxifloxacin in people with Schizophrenia, run by Merck Sharp & Dohme LLC at 4 sites in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

Search all trials

Trial summary

Who is it for?: Ages 18 to 60 years
Conditions the study is for: Schizophrenia
What is being tested?: Elpipodect and Moxifloxacin
Type of treatment: Pill or oral medicine
Could I receive a placebo?: Yes, some participants may receive a placebo
How many people: 107 participants
Where: 4 sitesUnited States
Study dates: 26 Jun 2023to 22 Feb 2024
Phase: Phase 1
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 18 to 60 years
All sexes
No healthy volunteers
Adult

Who may be able to join

Meets diagnostic criteria for schizophrenia or schizoaffective disorder according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria.
Is in the non-acute phase of their illness.
Has a history of receiving and tolerating antipsychotics medication within the usual dose range employed for schizophrenia.
Participants with hypothyroidism, diabetes, high blood pressure, chronic respiratory conditions or other medical conditions could be considered if their condition is stable.

Who cannot join

History of a primary DSM-5 axis I psychiatric diagnosis other than schizophrenia or schizoaffective disorder per the allowed DSM-5 criteria.
History of intellectual disability, borderline personality disorder, anxiety disorder, or organic brain syndrome.
History of neuroleptic malignant syndrome or moderate to severe tardive dyskinesia (TD).
History of seizure disorder beyond childhood or is receiving treatment with any anticonvulsant to prevent seizures.
History of cancer.
History or presence of sick sinus syndrome, atrioventricular (AV) block, myocardial infarction, pulmonary congestion, cardiac arrhythmia, prolonged QTc interval, or conduction abnormalities.

Show all 11Show fewer

History of risk factors for Torsades de Pointes (e.g., heart failure/cardiomyopathy or family history of long QT syndrome).
History of frequent syncope, vasovagal episodes, or epileptic seizures.
Family history of sudden cardiac death.
Has a positive test(s) for hepatitis B surface antigen (HBsAg), hepatitis C antibodies or human immunodeficiency virus (HIV).
Had major surgery, donated, or lost 1 unit of blood within 4 weeks prior to the pre-study visit.

Trial locations and contacts

4 sites in 1 country.

United States4 sites

California Clinical Trials Medical Group managed by PAREXEL-PAREXEL International ( Site 0003)
Glendale, California, 91206
Velocity Clinical Research, Hallandale Beach ( Site 0002)
Hallandale, Florida, 33009
Hassman Research Institute Marlton Site ( Site 0001)
Marlton, New Jersey, 08053
NRC Research Institute ( Site 0004)
Orange, California, 92868

Other trials in United States

About this study

Official title: A Double-Blind, Cross-Over Placebo-Controlled and Active-Controlled Trial To Evaluate The Effect Of A Supratherapeutic Dose Of MK-8189 On The QTc Interval In Participants With Schizophrenia

The primary purpose of this study to evaluate the effect of a supratherapeutic dose of 80 mg elpipodect on the QT interval corrected for heart rate (QTc interval) and to assess the safety and tolerability of multiple once-daily doses of elpipodect in participants with schizophrenia. The effects of 3 treatment sequences 1) elpipodect (48 mg [Day 1] and 80 mg [Day2]); 2) standard image placebo (Day 1) and moxifloxacin 400 mg (Day 2); and 3) elpipodect placebo (Day 1 and Day 2) were assessed with 5-day washout intervening sequence. Participants received all treatments in a counter-balanced order according to 1 of 6 possible treatment sequences.

The primary hypothesis is that the administration of an 80 mg elpipodect dose on Day 2 does not prolong the QTc interval to a clinically significant degree. Specifically, the true mean difference (elpipodect - placebo) in QTc change from baseline is less than 10 milliseconds (msec).

Conditions: Schizophrenia
Being tested: Elpipodect, Moxifloxacin, Placebo
Medical subject headings: Schizophrenia

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

ElpipodectDrug
Also called MK-8189
Oral Tablet
MoxifloxacinDrug
Oral Tablet
PlaceboDrug
Oral Tablet

Study groups in NCT05893862
Study group	Role	What they receive
Sequence 1: Elpipodect (Treatment A)→Moxifloxacin (Treatment B)→Placebo (Treatment C)	Experimental	Participants receive a sequence of Treatment A in Period 1 followed by Treatment B in Period 2 followed by Treatment C in Period 3; there will be a 5-day washout between periods. Treatment A consists of elpipodect administered orally at 48 mg on Day 1 and 80 mg on day 2. Treatment B consists of placebo administered orally on Day 1 and moxifloxacin administered orally at 400 mg on Day 2. Treatment C consists of placebo administered orally on Day 1 and Day 2. Receives: Drug: Elpipodect; Drug: Moxifloxacin; Drug: Placebo
Sequence 2: Moxifloxacin (Treatment B) →Placebo (Treatment C) →Elpipodect (Treatment A)	Experimental	Participants receive a sequence of Treatment B in Period 1 followed by Treatment C in Period 2 followed by Treatment A in Period 3; there will be a 5-day washout between periods. Treatment B consists of placebo administered orally on Day 1 and moxifloxacin administered orally at 400 mg on Day 2. Treatment C consists of placebo administered orally on Day 1 and Day 2. Treatment A consists of elpipodect administered orally at 48 mg on Day 1 and 80 mg on Day 2. Receives: Drug: Elpipodect; Drug: Moxifloxacin; Drug: Placebo
Sequence 3: Placebo (Treatment C) →Elpipodect (Treatment A) →Moxifloxacin (Treatment B)	Experimental	Participants receive a sequence of Treatment C in Period 1 followed by Treatment A in in Period 2 followed by Treatment B in Period 3; there will be a 5-day washout between periods. Treatment C consists of placebo administered orally on Day 1 and Day 2. Treatment A consists of elpipodect administered orally at 48 mg on Day 1 and 80 mg on Day 2. Treatment B consists of placebo administered orally on Day 1 and moxifloxacin administered orally at 400 mg on Day 2. Receives: Drug: Elpipodect; Drug: Moxifloxacin; Drug: Placebo
Sequence 4: Moxifloxacin (Treatment B) →Elpipodect (Treatment A) → Placebo (Treatment C)	Experimental	Participants receive a sequence of Treatment B in Period 1 followed by Treatment A in Period 2 followed by Treatment C in Period 3; there will be a 5-day washout between periods. Treatment B consists of placebo administered orally on Day 1 and moxifloxacin administered orally at 400 mg on Day 2. Treatment A consists of elpipodect administered orally at 48 mg on Day 1 and 80 mg on Day 2. Treatment C consists of placebo administered orally on Day 1 and Day 2. Receives: Drug: Elpipodect; Drug: Moxifloxacin; Drug: Placebo
Sequence 5: Elpipodect (Treatment A) →Placebo (Treatment C) →Moxifloxacin (Treatment B)	Experimental	Participants receive a sequence of Treatment A in Period 1 followed by Treatment C in Period 2 followed by Treatment B in Period 3; there will be a 5-day washout between periods. Treatment A consists of elpipodect administered orally at 48 mg on Day 1 and 80 mg on Day 2. Treatment C consists of placebo administered orally on Day 1 and Day 2. Treatment B consists of placebo administered orally on Day 1 and moxifloxacin administered orally at 400 mg on Day 2. Receives: Drug: Elpipodect; Drug: Moxifloxacin; Drug: Placebo
Sequence 6: Placebo (Treatment C) →Moxifloxacin (Treatment B) → Elpipodect (Treatment A)	Experimental	Participants receive a sequence of Treatment C in Period 1 followed by Treatment B in Period 2 followed by Treatment A in Period 3; there will be a 5-day washout between periods. Treatment C consists of placebo administered orally on Day 1 and Day 2. Treatment B consists of placebo administered orally on Day 1 and moxifloxacin administered orally at 400 mg on Day 2. Treatment A consists of elpipodect administered orally at 48 mg on Day 1 and 80 mg on Day 2. Receives: Drug: Elpipodect; Drug: Moxifloxacin; Drug: Placebo

What is being measured

The primary outcome is the main question the study is designed to answer.

Change From Baseline in QT Interval Corrected for Heart Rate (QTc) Following MK-8189 Treatment
Electrocardiogram data was obtained using a digital Holter device and the Fridericia correction of the QT interval (QTcF) was determined. The change from baseline in QTcF (ΔQTcF [msec]) was calculated by subtracting the QTcF value at the timepoint from the QTcF baseline value. Negative values represent a decrease from baseline and vice versa. An average of up to 9 predose ECGs on Day 1 served as baseline to compare postdose effects. Per protocol, the primary endpoint compares MK-8189 to placebo.
Measured: Day 1 (MK-8189 48 mg and placebo) and Day 2 (MK-8189 80 mg and placebo)
Number of Participants With Adverse Events (AEs)
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
Measured: Up to ~30 days after each dose
Number of Participants Discontinuing Study Therapy Due to AE
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
Measured: Up to ~30 days after each dose

Secondary outcomes (7)

Change From Baseline in QT Interval Corrected for Heart Rate (QTc) Following Moxifloxacin Treatment
Electrocardiogram data was obtained using a digital Holter device and the Fridericia correction of the QT interval (QTcF) was determined. The change from baseline in QTcF (ΔQTcF [msec]) was calculated by subtracting the QTcF value at the timepoint from the QTcF baseline value. Negative values represent a decrease from baseline and vice versa. An average of up to 9 predose ECGs on Day 1 served as baseline to compare postdose effects. Per protocol, the secondary endpoint compares moxifloxacin to placebo on Day 2. Moxifloxacin was tested for statistical significance 1 to 4 hours postdose (ie, around moxifloxacin Cmax) to ensure assay sensitivity. Hochberg's step-up method was applied to preserve the overall α level at .05 for the hypothesis testing.
Measured: Day 2
Area Under the Plasma Concentration-Time Curve From Time 0 to 24 Hours (AUC0-24) of MK-8189
AUC0-24 is defined as the area under concentration-time curve from 0 to 24 hours postdose. Blood samples taken at pre-dose and up to 24 hours post-dose will be used to determine the AUC0-24 of MK-8189.
Measured: Day 1: predose and 0.5, 1, 2, 3, 4, 6, 8, 12, 14, 24 hours postdose; Day 2: 0.5, 1, 2, 3, 4, 8, 11, 14, 16, 24 hours postdose
Area Under the Plasma Concentration-Time Curve From Time 0 to Last Measurable Concentration (AUC0-last) of MK-8189
AUC0-last is defined as the area under concentration-time curve from 0 to 24 hours. Blood samples taken at pre-dose and up to 72 hours post-dose will be used to extrapolate the AUC0-last of MK-8189.
Measured: Day 1: Pre-dose, 0.5, 1, 2, 3, 4, 6, 8, 12, 14, 24 hours postdose; Day 2: 0.5, 1, 2, 3, 4, 8, 11, 14, 16, 24, 36, 48, and 72 hours postdose
Maximum Concentration (Cmax) of MK-8189
Cmax is the maximum plasma concentration of MK-8189.
Measured: Day 1: predose and 0.5, 1, 2, 3, 4, 6, 8, 12, 14, 24 hours postdose; Day 2: 0.5, 1, 2, 3, 4, 8, 11, 14, 16, 24, 36, 48, 72 hours postdose
Concentration of MK-8189 at 24 Hours (C24) Post-dose
C24 is the plasma concentration 24 hours postdose.
Measured: Day 1 and Day 2: 24 hours postdose
Apparent Terminal Half-life (t½) of MK-8189
t½ is the time required for the Cmax plasma concentration to reduce by 50%. Per protocol, t½ was determined only for MK-8189 80 mg.
Measured: Day 2: 0.5, 1, 2, 3, 4, 8, 11, 14, 16, 24, 36, 48, 72 hours postdose
Time to Maximum Concentration (Tmax) of MK-8189
Tmax is defined as the time to reach Cmax.
Measured: Day 1: Pre-dose, 0.5, 1, 2, 3, 4, 6, 8, 12, 14, and 24 hours postdose; Day 2: 0.5, 1, 2, 3, 4, 8, 11, 14, 16, 24, 36, 48, and 72 hours postdose

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

26 Jun 202322 Feb 2024

First posted8 Jun 2023
Study start26 Jun 2023
Primary completion22 Feb 2024
Study completion22 Feb 2024

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Other trials for SchizophreniaStudies of the same condition, open and under way.
More trials run by Merck Sharp & Dohme LLCThe sponsor's other registered studies.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase 1
Primary purpose: Treatment
Allocation: Randomised
Intervention model: Crossover
Masking: Double blind
Who is masked: Participant, Investigator
Enrolment: 107 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT05893862
Sponsor's protocol ID: 8189-019
Other IDs: MK-8189-019
Acronym: TQT
Status last verified: Apr 2026
First submitted: 30 May 2023
Last updated: 29 Apr 2026
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: No
FDA-regulated drug: Yes
FDA-regulated device: No
Individual data sharing: Yes: https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

RecruitingPhase 2
Study to Evaluate the Safety and Efficacy of Ublituximab in Participants With Schizophrenia
Schizophrenia
RecruitingPhase 3
Relapse Prevention Trial Evaluating KarXT Treatment in Schizophrenia
Schizophrenia
Recruiting
Magnetic Seizure Therapy for Schizophrenia - Trial
Treatment Resistant Schizophrenia, Schizophrenia
Recruiting
Developing Biomarker-Supported Schizophrenia Spectrum Disorder (SSD) Prevention
Schizophrenia Spectrum Disorders (SSD)
RecruitingObservational study
Sensory Profile and Early Clinical Signs of Calm Room Users
Psychotic Disorders, Personality Disorders

All Schizophrenia trials

Study at a glance

From the registry record, last updated by the sponsor on 29 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: A Double-Blind, Cross-Over Placebo-Controlled and Active-Controlled Trial To Evaluate The Effect Of A Supratherapeutic Dose Of MK-8189 On The QTc Interval In Participants With Schizophrenia
ClinicalTrials.gov ID: NCT05893862
Acronym / sponsor ID: TQT / 8189-019
Conditions: Schizophrenia
Phase: Phase 1
Study type: Interventional
Recruitment status: Completed
Enrolment: 107 participants (actual)
Lead sponsor: Merck Sharp & Dohme LLCIndustry (pharma, biotech, devices)
Study start: 26 Jun 2023 (actual)
Primary completion: 22 Feb 2024 (actual)
Study completion: 22 Feb 2024 (actual)
First posted: 8 Jun 2023 (actual)
Results: Posted 22 Apr 2025

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Study design

Primary purpose: Treatment
Allocation: Randomised
Intervention model: Crossover
Masking: Double blind (participant, investigator)
Number of arms: 6

Arm	Type	Receives
Sequence 1: Elpipodect (Treatment A)→Moxifloxacin (Treatment B)→Placebo (Treatment C)	Experimental	Drug: Elpipodect, Drug: Moxifloxacin, Drug: PlaceboParticipants receive a sequence of Treatment A in Period 1 followed by Treatment B in Period 2 followed by Treatment C in Period 3; there will be a 5-day washout between periods. Treatment A consists of elpipodect administered orally at 48 mg on Day 1 and 80 mg on day 2. Treatment B consists of placebo administered orally on Day 1 and moxifloxacin administered orally at 400 mg on Day 2. Treatment C consists of placebo administered orally on Day 1 and Day 2.
Sequence 2: Moxifloxacin (Treatment B) →Placebo (Treatment C) →Elpipodect (Treatment A)	Experimental	Drug: Elpipodect, Drug: Moxifloxacin, Drug: PlaceboParticipants receive a sequence of Treatment B in Period 1 followed by Treatment C in Period 2 followed by Treatment A in Period 3; there will be a 5-day washout between periods. Treatment B consists of placebo administered orally on Day 1 and moxifloxacin administered orally at 400 mg on Day 2. Treatment C consists of placebo administered orally on Day 1 and Day 2. Treatment A consists of elpipodect administered orally at 48 mg on Day 1 and 80 mg on Day 2.
Sequence 3: Placebo (Treatment C) →Elpipodect (Treatment A) →Moxifloxacin (Treatment B)	Experimental	Drug: Elpipodect, Drug: Moxifloxacin, Drug: PlaceboParticipants receive a sequence of Treatment C in Period 1 followed by Treatment A in in Period 2 followed by Treatment B in Period 3; there will be a 5-day washout between periods. Treatment C consists of placebo administered orally on Day 1 and Day 2. Treatment A consists of elpipodect administered orally at 48 mg on Day 1 and 80 mg on Day 2. Treatment B consists of placebo administered orally on Day 1 and moxifloxacin administered orally at 400 mg on Day 2.
Sequence 4: Moxifloxacin (Treatment B) →Elpipodect (Treatment A) → Placebo (Treatment C)	Experimental	Drug: Elpipodect, Drug: Moxifloxacin, Drug: PlaceboParticipants receive a sequence of Treatment B in Period 1 followed by Treatment A in Period 2 followed by Treatment C in Period 3; there will be a 5-day washout between periods. Treatment B consists of placebo administered orally on Day 1 and moxifloxacin administered orally at 400 mg on Day 2. Treatment A consists of elpipodect administered orally at 48 mg on Day 1 and 80 mg on Day 2. Treatment C consists of placebo administered orally on Day 1 and Day 2.
Sequence 5: Elpipodect (Treatment A) →Placebo (Treatment C) →Moxifloxacin (Treatment B)	Experimental	Drug: Elpipodect, Drug: Moxifloxacin, Drug: PlaceboParticipants receive a sequence of Treatment A in Period 1 followed by Treatment C in Period 2 followed by Treatment B in Period 3; there will be a 5-day washout between periods. Treatment A consists of elpipodect administered orally at 48 mg on Day 1 and 80 mg on Day 2. Treatment C consists of placebo administered orally on Day 1 and Day 2. Treatment B consists of placebo administered orally on Day 1 and moxifloxacin administered orally at 400 mg on Day 2.
Sequence 6: Placebo (Treatment C) →Moxifloxacin (Treatment B) → Elpipodect (Treatment A)	Experimental	Drug: Elpipodect, Drug: Moxifloxacin, Drug: PlaceboParticipants receive a sequence of Treatment C in Period 1 followed by Treatment B in Period 2 followed by Treatment A in Period 3; there will be a 5-day washout between periods. Treatment C consists of placebo administered orally on Day 1 and Day 2. Treatment B consists of placebo administered orally on Day 1 and moxifloxacin administered orally at 400 mg on Day 2. Treatment A consists of elpipodect administered orally at 48 mg on Day 1 and 80 mg on Day 2.

Who may qualify

Ages: 18 to 60 years
Sex: All
Healthy volunteers: Not accepted
Age groups: Adult

Key inclusion criteria (4 listed)

Meets diagnostic criteria for schizophrenia or schizoaffective disorder according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria.
Is in the non-acute phase of their illness.
Has a history of receiving and tolerating antipsychotics medication within the usual dose range employed for schizophrenia.
Participants with hypothyroidism, diabetes, high blood pressure, chronic respiratory conditions or other medical conditions could be considered if their condition is stable.

Key exclusion criteria (11 listed)

History of a primary DSM-5 axis I psychiatric diagnosis other than schizophrenia or schizoaffective disorder per the allowed DSM-5 criteria.
History of intellectual disability, borderline personality disorder, anxiety disorder, or organic brain syndrome.
History of neuroleptic malignant syndrome or moderate to severe tardive dyskinesia (TD).
History of seizure disorder beyond childhood or is receiving treatment with any anticonvulsant to prevent seizures.
History of cancer.

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
ElpipodectAlso: MK-8189Oral Tablet	Drug	Sequence 1: Elpipodect (Treatment A)→Moxifloxacin (Treatment B)→Placebo (Treatment C), Sequence 2: Moxifloxacin (Treatment B) →Placebo (Treatment C) →Elpipodect (Treatment A), Sequence 3: Placebo (Treatment C) →Elpipodect (Treatment A) →Moxifloxacin (Treatment B), Sequence 4: Moxifloxacin (Treatment B) →Elpipodect (Treatment A) → Placebo (Treatment C), Sequence 5: Elpipodect (Treatment A) →Placebo (Treatment C) →Moxifloxacin (Treatment B), Sequence 6: Placebo (Treatment C) →Moxifloxacin (Treatment B) → Elpipodect (Treatment A)
MoxifloxacinOral Tablet	Drug	Sequence 1: Elpipodect (Treatment A)→Moxifloxacin (Treatment B)→Placebo (Treatment C), Sequence 2: Moxifloxacin (Treatment B) →Placebo (Treatment C) →Elpipodect (Treatment A), Sequence 3: Placebo (Treatment C) →Elpipodect (Treatment A) →Moxifloxacin (Treatment B), Sequence 4: Moxifloxacin (Treatment B) →Elpipodect (Treatment A) → Placebo (Treatment C), Sequence 5: Elpipodect (Treatment A) →Placebo (Treatment C) →Moxifloxacin (Treatment B), Sequence 6: Placebo (Treatment C) →Moxifloxacin (Treatment B) → Elpipodect (Treatment A)
PlaceboOral Tablet	Drug	Sequence 1: Elpipodect (Treatment A)→Moxifloxacin (Treatment B)→Placebo (Treatment C), Sequence 2: Moxifloxacin (Treatment B) →Placebo (Treatment C) →Elpipodect (Treatment A), Sequence 3: Placebo (Treatment C) →Elpipodect (Treatment A) →Moxifloxacin (Treatment B), Sequence 4: Moxifloxacin (Treatment B) →Elpipodect (Treatment A) → Placebo (Treatment C), Sequence 5: Elpipodect (Treatment A) →Placebo (Treatment C) →Moxifloxacin (Treatment B), Sequence 6: Placebo (Treatment C) →Moxifloxacin (Treatment B) → Elpipodect (Treatment A)

Primary outcome

Change From Baseline in QT Interval Corrected for Heart Rate (QTc) Following MK-8189 Treatment
Time frame: Day 1 (MK-8189 48 mg and placebo) and Day 2 (MK-8189 80 mg and placebo)
Electrocardiogram data was obtained using a digital Holter device and the Fridericia correction of the QT interval (QTcF) was determined. The change from baseline in QTcF (ΔQTcF [msec]) was calculated by subtracting the QTcF value at the timepoint from the QTcF baseline value. Negative values represent a decrease from baseline and vice versa. An average of up to 9 predose ECGs on Day 1 served as baseline to compare postdose effects. Per protocol, the primary endpoint compares MK-8189 to placebo.
Number of Participants With Adverse Events (AEs)
Time frame: Up to ~30 days after each dose
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
Number of Participants Discontinuing Study Therapy Due to AE
Time frame: Up to ~30 days after each dose
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.

7 secondary outcomes

Change From Baseline in QT Interval Corrected for Heart Rate (QTc) Following Moxifloxacin Treatment
Time frame: Day 2
Area Under the Plasma Concentration-Time Curve From Time 0 to 24 Hours (AUC0-24) of MK-8189
Time frame: Day 1: predose and 0.5, 1, 2, 3, 4, 6, 8, 12, 14, 24 hours postdose; Day 2: 0.5, 1, 2, 3, 4, 8, 11, 14, 16, 24 hours postdose
Area Under the Plasma Concentration-Time Curve From Time 0 to Last Measurable Concentration (AUC0-last) of MK-8189
Time frame: Day 1: Pre-dose, 0.5, 1, 2, 3, 4, 6, 8, 12, 14, 24 hours postdose; Day 2: 0.5, 1, 2, 3, 4, 8, 11, 14, 16, 24, 36, 48, and 72 hours postdose
Maximum Concentration (Cmax) of MK-8189
Time frame: Day 1: predose and 0.5, 1, 2, 3, 4, 6, 8, 12, 14, 24 hours postdose; Day 2: 0.5, 1, 2, 3, 4, 8, 11, 14, 16, 24, 36, 48, 72 hours postdose
Concentration of MK-8189 at 24 Hours (C24) Post-dose
Time frame: Day 1 and Day 2: 24 hours postdose
Apparent Terminal Half-life (t½) of MK-8189
Time frame: Day 2: 0.5, 1, 2, 3, 4, 8, 11, 14, 16, 24, 36, 48, 72 hours postdose
Time to Maximum Concentration (Tmax) of MK-8189
Time frame: Day 1: Pre-dose, 0.5, 1, 2, 3, 4, 6, 8, 12, 14, and 24 hours postdose; Day 2: 0.5, 1, 2, 3, 4, 8, 11, 14, 16, 24, 36, 48, and 72 hours postdose

Results and safety

Results posted to the registry on 22 Apr 2025, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Sequence A/B/C	15	13
Sequence A/C/B	25	13
Sequence B/A/C	15	12
Sequence B/C/A	18	13
Sequence C/A/B	20	15
Sequence C/B/A	14	12

Primary outcome: Change From Baseline in QT Interval Corrected for Heart Rate (QTc) Following MK-8189 Treatment

Time frame: Day 1 (MK-8189 48 mg and placebo) and Day 2 (MK-8189 80 mg and placebo). Mean (95% Confidence Interval). Unit: ΔQTcF (msec)

Measure	MK-8189 48 mg Day 1 n = 95	Placebo Day 1 n = 87	MK-8189 80 mg Day 2 n = 91	Placebo Day 2 n = 84	Standard Image Placebo Day 1 n = 0	Moxifloxacin 400 mg Day 2 n = 0
Predose (Day 2 only)	–	–	4.31 (2.45 to 6.16)	-1.38 (-3.24 to 0.49)	–	–
0.5 Hr	-0.61 (-1.87 to 0.66)	-1.13 (-2.84 to 0.57)	–	–	–	–
1 hr	0.29 (-1.50 to 2.08)	0.48 (-1.25 to 2.20)	3.60 (1.33 to 5.87)	-0.76 (-2.95 to 1.43)	–	–
2 hr	2.68 (0.21 to 5.16)	1.06 (-1.35 to 3.46)	5.14 (2.40 to 7.87)	0.92 (-1.74 to 3.58)	–	–
3 hr	2.18 (-0.61 to 4.97)	-1.35 (-4.03 to 1.34)	3.31 (0.50 to 6.11)	-2.22 (-5.17 to 0.72)	–	–
4 hr	2.80 (0.07 to 5.53)	-3.19 (-5.73 to -0.64)	2.64 (0.11 to 5.16)	-2.67 (-5.40 to 0.05)	–	–
6 hr (Day 1 only)	7.38 (4.75 to 10.00)	0.25 (-2.51 to 3.02)	–	-3.10 (-5.82 to -0.39)	–	–
8 hr	8.75 (6.51 to 10.98)	-0.97 (-3.57 to 1.64)	2.82 (0.25 to 5.40)	-1.93 (-4.83 to 0.98)	–	–

MK-8189 48 mg Day 1 vs Placebo Day 1: LS Mean Difference: 0.52 (90% CI -1.11 to 2.14)
MK-8189 48 mg Day 1 vs Placebo Day 1: LS Mean Difference: 0.36 (90% CI -1.26 to 1.98)
MK-8189 48 mg Day 1 vs Placebo Day 1: LS Mean Difference: 1.31 (90% CI -1.04 to 3.66)

Population analysed: All participants who received ≥1 dose of MK-8189, and who complied with the protocol sufficiently to ensure that generated data will likely exhibit the effects of treatment (according to the underlying scientific model), are included.

Primary outcome: Number of Participants With Adverse Events (AEs)

Time frame: Up to ~30 days after each dose. Count of participants. Unit: Participants

Measure	MK-8189 48 mg Day 1 n = 98	Placebo Days 1 and 2 n = 90	MK-8189 80 mg Day 2 n = 92	Standard Image Placebo Day 1 n = 89	Moxifloxacin 400 mg Day 2 n = 89
Value	25	16	21	7	11

Population analysed: All treated participants are included.

Primary outcome: Number of Participants Discontinuing Study Therapy Due to AE

Time frame: Up to ~30 days after each dose. Count of participants. Unit: Participants

Measure	MK-8189 48 mg Day 1 n = 98	Placebo Days 1 and 2 n = 90	MK-8189 80 mg Day 2 n = 92	Standard Image Placebo Day 1 n = 89	Moxifloxacin 400 mg Day 2 n = 89
Value	3	1	4	0	2

Population analysed: All treated participants are included.

7 secondary outcomes are reported in the full results.

Adverse events

Time frame: Up to ~30 days after each dose. Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
MK-8189 48 mg	1 of 98 (1%)	24 of 98 (24.5%)	0 of 98
MK-8189 80 mg	0 of 92 (0%)	21 of 92 (22.8%)	0 of 92
MK-8189 Placebo	1 of 90 (1.1%)	15 of 90 (16.7%)	0 of 90
Standard Image Placebo Day 1	0 of 89 (0%)	7 of 89 (7.9%)	0 of 89
Moxifloxacin 400 mg Day 2	0 of 89 (0%)	11 of 89 (12.4%)	0 of 89

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 29 Apr 2026.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Merck Clinical Trials InformationLink provided by the sponsor.
Individual participant dataSharing planned: Yes. https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf

Related trials for Schizophrenia

RecruitingPhase 2
Study to Evaluate the Safety and Efficacy of Ublituximab in Participants With Schizophrenia
Schizophrenia
RecruitingPhase 3
Relapse Prevention Trial Evaluating KarXT Treatment in Schizophrenia
Schizophrenia
Recruiting
Magnetic Seizure Therapy for Schizophrenia - Trial
Treatment Resistant Schizophrenia, Schizophrenia
Recruiting
Developing Biomarker-Supported Schizophrenia Spectrum Disorder (SSD) Prevention
Schizophrenia Spectrum Disorders (SSD)
RecruitingObservational study
Sensory Profile and Early Clinical Signs of Calm Room Users
Psychotic Disorders, Personality Disorders

Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Medical Director study director

Merck Sharp & Dohme LLC

4 sites in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

A Phase 1 study testing Elpipodect and Moxifloxacin in people with Schizophrenia, run by Merck Sharp & Dohme LLC at 4 sites in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 11 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 29 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 4 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 22 Apr 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change From Baseline in QT Interval Corrected for Heart Rate (QTc) Following MK-8189 Treatment (time frame: Day 1 (MK-8189 48 mg and placebo) and Day 2 (MK-8189 80 mg and placebo)). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05893862.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 29 Apr 2026.