MK-5720 + MK-8189 for Schizophrenia

No longer recruiting at 4 trial locations
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Age: 18 - 65
Sex: Any
Trial Phase: Phase 1
Sponsor: Merck Sharp & Dohme LLC
Must be taking: Antipsychotics
No Placebo GroupAll trial participants will receive the active study treatment (no placebo)

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial examines the safety and behavior of two new treatments, MK-5720 and MK-8189, in individuals with schizophrenia. Participants will receive these medicines either as an oral pill or an injection to assess tolerance. The trial seeks individuals who have had schizophrenia or schizoaffective disorder for at least two years and are currently on antipsychotic medication. As a Phase 1 trial, this research aims to understand how the treatment works in people, offering participants the opportunity to be among the first to receive these new treatments.

Will I have to stop taking my current medications?

Yes, you will need to stop taking all antipsychotic medications at least 5 days or 3 half-lives (whichever is longer) before starting the treatment and during the study.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

A previous study showed that MK-8189 was quite safe, with no deaths or serious side effects reported among participants. Researchers tested different doses, including 8 mg, 16 mg, and 24 mg, and found it well-tolerated.

For MK-5720, less information is available. The current trial, in its early stages, primarily focuses on safety, so researchers are still learning how well participants handle it.

Both treatments are closely monitored for side effects in current studies, a standard practice in early research to ensure participant safety.12345

Why are researchers excited about this trial's treatments?

MK-5720 and MK-8189 are unique because they represent a novel approach to treating schizophrenia by combining oral and intramuscular delivery methods. Unlike typical antipsychotics that primarily target dopamine receptors, these treatments potentially offer an alternative mechanism of action, which might address symptoms in patients who don't respond well to existing medications like risperidone or olanzapine. Researchers are excited about the possibility of these treatments offering more rapid symptom relief, as they involve a brief oral treatment followed by a single injection, potentially reducing the time needed to see improvements compared to standard therapies.

What evidence suggests that this trial's treatments could be effective for schizophrenia?

Early research suggests that MK-8189, one of the treatments studied in this trial, might alleviate symptoms of schizophrenia. Studies have shown that patients taking MK-8189 tend to improve more than those on a placebo, with better scores on tests measuring schizophrenia symptoms. MK-8189 works by blocking an enzyme called PDE10A, which might help reduce symptoms like hallucinations and delusions.

For MK-5720, another treatment option in this trial, little information exists on its effectiveness for schizophrenia. Currently, researchers are primarily examining its safety and how the body processes it. Both treatments are under study in this trial, but MK-8189 appears more promising based on early results.12678

Who Is on the Research Team?

MD

Medical Director

Principal Investigator

Merck Sharp & Dohme LLC

Are You a Good Fit for This Trial?

This trial is for individuals with schizophrenia or schizoaffective disorder, diagnosed at least 2 years ago. Participants must have a history of tolerating antipsychotic medications and can stop their current medication for the study duration. They cannot join if they have severe allergies, metal implants preventing MRI scans, certain infections like HIV or hepatitis, are at risk of self-harm, or have specific psychiatric exclusions.

Inclusion Criteria

I have been diagnosed with schizophrenia or schizoaffective disorder for over 2 years and need antipsychotic medication.
I have taken and tolerated antipsychotic medication for schizophrenia before.
I can stop taking my antipsychotic medication before and during the study.

Exclusion Criteria

Has a substance-induced psychotic disorder or behavioral disturbance thought to be due to substance abuse
I have been treated with clozapine.
Is at imminent risk of self-harm, based on clinical interview and responses on the Columbia-Suicide Severity Rating Scale (C-SSRS), or of harm to others in the opinion of the investigator
See 10 more

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Period 1: Oral Treatment

Participants receive once-daily oral doses of MK-8189 or placebo for 7 days

1 week
Daily visits (in-person or virtual)

Washout

A 72-hour washout period following the oral treatment phase

3 days

Period 2: Intramuscular Injection

Participants receive a single intramuscular dose of MK-5720 or placebo

1 day
1 visit (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

Up to approximately 72 days
Multiple visits (in-person or virtual) for blood sample collection

What Are the Treatments Tested in This Trial?

Interventions

  • MK-5720
  • MK-8189
Trial Overview The study tests MK-5720 given as single intramuscular doses and MK-8189 taken orally once daily against placebos to assess safety and how the body processes these drugs in people with schizophrenia. The hypothesis suggests that MK-5720 will be safe and well-tolerated.
How Is the Trial Designed?
6Treatment groups
Experimental Treatment
Group I: Panel FExperimental Treatment4 Interventions
Group II: Panel EExperimental Treatment4 Interventions
Group III: Panel DExperimental Treatment4 Interventions
Group IV: Panel CExperimental Treatment4 Interventions
Group V: Panel BExperimental Treatment4 Interventions
Group VI: Panel AExperimental Treatment4 Interventions

Find a Clinic Near You

Who Is Running the Clinical Trial?

Merck Sharp & Dohme LLC

Lead Sponsor

Trials
4,096
Recruited
5,232,000+
Chirfi Guindo profile image

Chirfi Guindo

Merck Sharp & Dohme LLC

Chief Marketing Officer since 2022

Degree in Engineering from Ecole Centrale de Paris, MBA from New York University Stern School of Business

Robert M. Davis profile image

Robert M. Davis

Merck Sharp & Dohme LLC

Chief Executive Officer since 2021

JD from Northwestern University Pritzker School of Law, MBA from Northwestern University Kellogg Graduate School of Management, Bachelor's in Finance from Miami University

Citations

A Study of MK-5720 in Participants With Schizophrenia ...The purpose of this study is to evaluate the safety, tolerability, and pharmacokinetics (PK) of single ascending intramuscular doses of MK-5720, ...
Neurosciences - Merck Clinical TrialsA Study of MK-5720 in Participants With Schizophrenia. Age. 18 - 60. Number of Locations. 0. Nearest Location. N/A. Sexes Studied. Male/Female. Condition.
MK-5720 by Merck for Schizophrenia: Likelihood of ApprovalAccording to GlobalData, Phase I drugs for Schizophrenia have a 66% phase transition success rate (PTSR) indication benchmark for progressing into Phase II.
Schizophrenia Pipeline Outlook 2025: Clinical Trial Studies ...On 22 August 2025, Merck Sharp & Dohme LLC organized a study was to evaluate the efficacy and safety of MK-8189 at a range of doses (8 mg, 16 mg ...
A Study of MK-5720 in Participants With SchizophreniaThe purpose of this study is to evaluate the safety, tolerability, and pharmacokinetics (PK) of single ascending intramuscular doses of MK-5720, ...
A Study of MK-5720 in Participants With Schizophrenia ...This study aims to assess the safety and tolerability of MK-5720 in individuals diagnosed with schizophrenia. The focus is on evaluating how ...
MK-5720 - Drug Targets, Indications, PatentsA single ascending dose study to evaluate the safety, tolerability, and pharmacokinetics of the long-acting injectable of MK-5720 in participants with ...
Clinical Trial - WebHealth NetworkThe primary study hypothesis is that the administration of MK-5720 is safe and well tolerated. Read More. WebHealth AI Chat.
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