Schizophrenia, Acute EpisodePhase 2NCT03055338
An Active-Controlled Early Phase Study of Elpipodect (MK-8189) in Adults With Schizophrenia (MK-8189-005)
A Phase 2 study testing Elpipodect and Risperidone in people with Schizophrenia, Acute Episode, run by Merck Sharp & Dohme LLC at 28 sites in United States.
Trial summary
This will be a randomized, placebo-controlled, parallel-group, multi-site, double-blind trial of elpipodect compared with placebo, using Risperidone as an active control. The participants will be adult subjects experiencing an acute episode of schizophrenia, according to the criteria specified in the Diagnostic and… Read more about this study
- Who is it for?
- Ages 18 to 50 years
- Conditions the study is for
- Schizophrenia, Acute Episode
- What is being tested?
- Elpipodect and Risperidone
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 224 participants
- Where
- 28 sitesUnited States
- Study dates
- 8 Mar 2017to 9 Jan 2018
- Phase
- Phase 2
- 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 50 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- 18 to 50 years of age at Screening
- Male
- Female not of reproductive potential (e.g., postmenopausal or has had a hysterectomy), or agrees to practice abstinence or use acceptable contraception
- Meets the diagnostic criteria for schizophrenia according to the DSM-5 criteria, or has a past diagnosis of schizophrenia with the onset of the first episode being >=1 year prior to study entry, and has illness duration of <=20 years
- Is confirmed to be experiencing an acute episode of schizophrenia
- Minimum PANSS score >= 80 at Screening
Show all 11Show fewer
- Has a score of >=4 in 3 or more of the following items (delusions, conceptual disorganization, hallucinatory behavior, grandiosity, suspiciousness/persecution) in the positive subscale of the PANSS at Screening
- Has a CGI-S score >= 4 at Screening
- Is able to taper off psychotropic medications without significant destabilization or increased suicidality
- Has responded positively to an antipsychotic medication other than clozapine in a prior psychotic episode
- Has an identified responsible external contact person who has regular contact (no less than once per week) with the participant
Who cannot join
- Is currently under involuntary commitment because he/she is considered a danger to himself/herself or others
- Is unwilling to remain hospitalized for the duration of trial treatment
- Is currently participating in or has participated in an interventional clinical research study <=6 months prior to Screening, or has participated in more than one interventional clinical trial research study within 12 months prior to Screening
- Is unwilling to allow audio/video taping of the Mini International Neuropsychiatric Interview for Schizophrenia and Psychotic Disorders (MINI) and/or PANSS interview at Screening and Baseline
- Is currently being treated with and benefiting from medications with a moderate or strong inhibiting or inducing effect on Cytochrome P450 (CYP) 3A and/or CYP2C9 and/or sensitive substrates of CYP2B6
- Has a history of malignancy <= 5 years except for adequately treated basal cell or squamous cell skin cancer or in situ cervical cancer
Show all 17Show fewer
- Has a body mass index <18.5 or >40 kg/m˄2
- Has a history of treatment-resistant schizophrenia
- Has a prolactin laboratory value of >= 5 times the upper limit of normal at Screening
- Has a known history or clinical evidence of clinically significant hepatic, cardiovascular, or renal disease, or of untreated narrow-angle glaucoma- Has ever been diagnosed with epilepsy or had any seizure disorder beyond one childhood febrile seizure
- Has known serological evidence of human immunodeficiency virus (HIV) antibody
- Has a history of neuroleptic malignant syndrome
- Has a current diagnosis other than schizophrenia, or a comorbid diagnosis primarily responsible for current symptoms and functional impairment
- Has a known history of borderline personality disorder, antisocial personality disorder, or bipolar disorder
- Has a known history of traumatic brain injury, or Alzheimer's disease or another form of dementia
- Currently meets DSM-5 criteria for substance abuse or alcohol use disorder
- Is at imminent risk of self-harm or harm to others
Trial locations and contacts
28 sites in 1 country.
28 sites in 1 country
United States28 sites
Radiant Research - Atlanta ( Site 0008)
Atlanta, Georgia, 30328
Atlanta Center For Medical Research ( Site 0056)
Atlanta, Georgia, 30331
CITRIALS ( Site 0013)
Bellflower, California, 90706
Comprehensive Clinical Development ( Site 0049)
Cerritos, California, 90703
Midwest Clinical Research Unit ( Site 0041)
Dayton, Ohio, 45417
InSite Clinical Research ( Site 0033)
DeSoto, Texas, 75115
Precise Research Centers ( Site 0018)
Flowood, Mississippi, 39232
CBH Health, LLC ( Site 0022)
Gaithersburg, Maryland, 20877
Collaborative Neuroscience Network, LLC ( Site 0057)
Garden Grove, California, 92845
Behavioral Research Specialists, LLC ( Site 0006)
Glendale, California, 91206
Alexian Center for Psychiatric Research ( Site 0015)
Hoffman Estates, Illinois, 60169
Larkin Community Hospital Behavioral Health Services ( Site 0020)
Hollywood, Florida, 33021
Lake Charles Clinical Trials, LLC ( Site 0040)
Lake Charles, Louisiana, 70629
Altea Research Institute ( Site 0017)
Las Vegas, Nevada, 89102
Synergy East ( Site 0003)
Lemon Grove, California, 91945
Woodland International Research Group, LLC ( Site 0001)
Little Rock, Arkansas, 72211
Radiant Research -CliniLabs ( Site 0037)
New York, New York, 10019
Clinical Research Centers of America, LLC ( Site 0038)
Oakland Park, Florida, 33334
NRC Research Institute ( Site 0043)
Orange, California, 92868
Aspire Health Partners ( Site 0016)
Orlando, Florida, 32810
CNRI - Los Angeles, LLC ( Site 0026)
Pico Rivera, California, 90660
Pillar Clinical Research, LLC ( Site 0004)
Richardson, Texas, 75080
Woodland Research Northwest, LLC ( Site 0014)
Rogers, Arkansas, 72758
Artemis Institute for Clinical Research ( Site 0027)
San Diego, California, 92103
Schuster Medical Research Institute ( Site 0032)
Sherman Oaks, California, 91403
Psych Care Consultants Research ( Site 0025)
St Louis, Missouri, 63128
St. Louis Clinical Trials, LLC ( Site 0012)
St Louis, Missouri, 63141
Collaborative Neuroscience Network, LLC ( Site 0046)
Torrance, California, 90502
About this study
Official title: A Phase IIa, Randomized, Double-Blind, Placebo-Controlled Clinical Trial of the Efficacy and Safety of MK-8189 Using Risperidone as an Active Control in Subjects Experiencing an Acute Episode of Schizophrenia
This will be a randomized, placebo-controlled, parallel-group, multi-site, double-blind trial of elpipodect compared with placebo, using Risperidone as an active control. The participants will be adult subjects experiencing an acute episode of schizophrenia, according to the criteria specified in the Diagnostic and Statistical Manual of Mental Disorders, 5th ed. (DSM-5). This study will be up to 7 weeks in duration, with up to 7 site visits for each participant. The study will consist of a Screening/tapering period (up to one week long), a 4-week treatment period, and a 14-day follow-up period. The primary objective will be to assess symptoms of schizophrenia at 4 weeks, and to assess safety and tolerability during treatment and post-treatment follow-up. The secondary objective will be to assess the severity of schizophrenia at 4 weeks. The primary hypothesis is that elpipodect is superior to placebo in reducing the overall symptoms of schizophrenia as assessed by the mean change from baseline in the Positive and Negative Syndrome Scale (PANSS) total score after 4 weeks of treatment.
- Conditions
- Schizophrenia, Acute Episode
- Being tested
- Elpipodect, Risperidone, Placebo matching MK-8189, Placebo matching risperidone
- Keywords
- Schizophrenia, acute episode, Schizophrenia Spectrum and Other Psychotic Disorders, Mental Disorders
- Medical subject headings
- Schizophrenia, Schizophrenia Spectrum and Other Psychotic Disorders, Mental Disorders
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 CR tablets (4 mg) administered QD at the following dose strengths: 4 mg (1 tablet); 8 mg (2 tablets); 12 mg (3 tablets)
RisperidoneDrug
Oral capsules (2 mg) administered QD at the following dose strengths: 2 mg (1 capsule); 4 mg (2 capsules); 6 mg (3 capsules)
Placebo matching MK-8189Drug
Oral placebo tablet(s) matching the MK-8189 tablet, administered QD.
Placebo matching risperidoneDrug
Oral placebo capsule(s) matching the risperidone capsule, administered QD.
| Study group | Role | What they receive |
|---|---|---|
| Elpipodect | Experimental | Participants receive elpipodect (4 mg controlled release [CR] oral tablet[s]) in combination with placebo matching risperidone (oral capsule[s]) once daily (QD) for 4 weeks. Over the initial 7 treatment days, elpipodect is titrated from 4 mg to 12 mg as follows: 4 mg (1 tablet; Day 1); 8 mg (2 tablets; Day 4); and 12 mg (3 tablets; Day 7). Placebo matching risperidone is also titrated as follows: 1 capsule (Day 1), 2 capsules (Day 4), and 3 capsules (Day 7). After Day 7, elpipodect is maintained at 12 mg (3 tablets) in combination with placebo matching risperidone (3 capsules), QD for 3 weeks. Receives: Drug: Elpipodect; Drug: Placebo matching risperidone |
| Risperidone | Active comparator | Participants receive risperidone (2 mg oral capsule[s]) in combination with placebo matching elpipodect (oral tablet[s]), QD for 4 weeks. Over the initial 7 treatment days, risperidone is titrated from 2 mg to 6 mg as follows: 2 mg (1 capsule; Day 1); 4 mg (2 capsules; Day 4); and 6 mg (3 capsules; Day 7). Placebo matching elpipodect is also titrated as follows: 1 tablet (Day 1), 2 tablets (Day 4), and 3 tablets (Day 7). After Day 7, risperidone is maintained at 6 mg (3 capsules) in combination with placebo matching elpipodect (3 tablets), QD for 3 weeks. Receives: Drug: Risperidone; Drug: Placebo matching MK-8189 |
| Placebo | Placebo comparator | Participants receive both placebo matching elpipodect (oral tablet[s]) as well as placebo matching Risperidone (oral capsule[s]), QD for 4 weeks. Over the initial 7 treatment days, placebo matching both elpipodect and risperidone are respectively titrated as follows: 1 tablet/1 capsule (Day 1); 2 tablets/2 capsules (Day 4); and 3 tablets/3 capsules (Day 7). After Day 7, placebo matching both elpipodect and risperidone are respectively maintained at 3 tablets/3 capsules, QD for 3 weeks. Receives: Drug: Placebo matching MK-8189; Drug: Placebo matching risperidone |
What is being measured
The primary outcome is the main question the study is designed to answer.
Least Squares Mean (LSM) Change From Baseline in the Positive and Negative Syndrome Scale (PANSS) Total Score at Week 4
The LSM change from baseline at week 4 was assessed for PANSS total score. The PANSS assesses the severity of schizophrenia symptoms through a clinician-rated inventory of 30 items organized in 3 subscales: 1) positive subscale (7 items); 2) negative subscale (7 items); and 3) general psychopathology subscale (16 items). For each item, symptoms are scored from 1 (absent) to 7 (extreme) and sum to a total PANSS score (range: 30-210). Higher scores reflect more severe symptoms of schizophrenia. Further, reduced symptom severity over time is reflected by decreases in score.
Measured: Baseline and Week 4
Percentage of Participants Experiencing an Adverse Event (AE)
The percentage of participants experiencing an AE was assessed. An AE is defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening of a preexisting condition that is temporally associated with the use of the Sponsor's product, is also an AE.
Measured: Up to 6 weeks
Percentage of Participants Discontinuing Study Treatment Due to an Adverse Event
The percentage of participants discontinuing study treatment due to an AE was assessed. An AE is defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening of a preexisting condition that is temporally associated with the use of the Sponsor's product, is also an AE.
Measured: Up to 4 weeks
Secondary outcomes (1)
Least Squares Mean (LSM) Change From Baseline in the Clinical Global Impression-Severity of Illness (CGI-S) Score at Week 4
The LSM change from baseline at week 4 was assessed for CGI-S score. The CGI-S is a 7-point clinician-rated scale for assessing the global severity of the participant's illness. Possible CGI-S scores range from 1 (participant normal, not ill) to 7 (participant extremely ill). Further, a decrease in CGI-S score indicates reduced severity of the participant's illness.
Measured: Baseline and Week 4
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Feb 2017
- Study start8 Mar 2017
- Primary completion9 Jan 2018
- Study completion9 Jan 2018
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.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Schizophrenia, Acute EpisodeStudies 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 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Participants will be randomly assigned to one of three groups in parallel for the duration of the study.
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 224 participants (actual)
Sponsor and investigators
- Lead sponsor
- Merck Sharp & Dohme LLC
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Medical Director, Study director, Merck Sharp & Dohme LLC
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03055338
- Sponsor's protocol ID
- 8189-005
- Other IDs
- MK-8189-005
- Status last verified
- Apr 2026
- First submitted
- 14 Feb 2017
- 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
- No
Publications
Mukai Y, Lupinacci R, Marder S, Snow-Adami L, Voss T, Smith SM, Egan MF. Effects of PDE10A inhibitor MK-8189 in people with an acute episode of schizophrenia: A randomized proof-of-concept clinical trial. Schizophr Res. 2024 Aug;270:37-43. doi: 10.1016/j.schres.2024.05.019. Epub 2024 Jun 8.
PubMed 38851166
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 Phase IIa, Randomized, Double-Blind, Placebo-Controlled Clinical Trial of the Efficacy and Safety of MK-8189 Using Risperidone as an Active Control in Subjects Experiencing an Acute Episode of Schizophrenia
- ClinicalTrials.gov ID
- NCT03055338
- Acronym / sponsor ID
- 8189-005
- Conditions
- Schizophrenia, Acute Episode
- Keywords
- Schizophrenia, acute episode, Schizophrenia Spectrum and Other Psychotic Disorders, Mental Disorders
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 224 participants (actual)
- Lead sponsor
- Merck Sharp & Dohme LLCIndustry (pharma, biotech, devices)
- Study start
- 8 Mar 2017 (actual)
- Primary completion
- 9 Jan 2018 (actual)
- Study completion
- 9 Jan 2018 (actual)
- First posted
- 16 Feb 2017 (actual)
- Results
- Posted 26 Dec 2018
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This will be a randomized, placebo-controlled, parallel-group, multi-site, double-blind trial of elpipodect compared with placebo, using Risperidone as an active control. The participants will be adult subjects experiencing an acute episode of schizophrenia, according to the criteria specified in the Diagnostic and Statistical Manual of Mental Disorders, 5th ed. (DSM-5). This study will be up to 7 weeks in duration, with up to 7 site visits for each participant. The study will consist of a Screening/tapering period (up to one week long), a 4-week treatment period, and a 14-day follow-up period. The primary objective will be to assess symptoms of schizophrenia at 4 weeks, and to assess safety and tolerability during treatment and post-treatment follow-up. The secondary objective will be to assess the severity of schizophrenia at 4 weeks. The primary hypothesis is that elpipodect is superior to placebo in reducing the overall symptoms of schizophrenia as assessed by the mean change from baseline in the Positive and Negative Syndrome Scale (PANSS) total score after 4 weeks of treatment.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 3
- Model description
- Participants will be randomly assigned to one of three groups in parallel for the duration of the study.
| Arm | Type | Receives |
|---|---|---|
| Elpipodect | Experimental | Drug: Elpipodect, Drug: Placebo matching risperidoneParticipants receive elpipodect (4 mg controlled release [CR] oral tablet[s]) in combination with placebo matching risperidone (oral capsule[s]) once daily (QD) for 4 weeks. Over the initial 7 treatment days, elpipodect is titrated from 4 mg to 12 mg as follows: 4 mg (1 tablet; Day 1); 8 mg (2 tablets; Day 4); and 12 mg (3 tablets; Day 7). Placebo matching risperidone is also titrated as follows: 1 capsule (Day 1), 2 capsules (Day 4), and 3 capsules (Day 7). After Day 7, elpipodect is maintained at 12 mg (3 tablets) in combination with placebo matching risperidone (3 capsules), QD for 3 weeks. |
| Risperidone | Active comparator | Drug: Risperidone, Drug: Placebo matching MK-8189Participants receive risperidone (2 mg oral capsule[s]) in combination with placebo matching elpipodect (oral tablet[s]), QD for 4 weeks. Over the initial 7 treatment days, risperidone is titrated from 2 mg to 6 mg as follows: 2 mg (1 capsule; Day 1); 4 mg (2 capsules; Day 4); and 6 mg (3 capsules; Day 7). Placebo matching elpipodect is also titrated as follows: 1 tablet (Day 1), 2 tablets (Day 4), and 3 tablets (Day 7). After Day 7, risperidone is maintained at 6 mg (3 capsules) in combination with placebo matching elpipodect (3 tablets), QD for 3 weeks. |
| Placebo | Placebo comparator | Drug: Placebo matching MK-8189, Drug: Placebo matching risperidoneParticipants receive both placebo matching elpipodect (oral tablet[s]) as well as placebo matching Risperidone (oral capsule[s]), QD for 4 weeks. Over the initial 7 treatment days, placebo matching both elpipodect and risperidone are respectively titrated as follows: 1 tablet/1 capsule (Day 1); 2 tablets/2 capsules (Day 4); and 3 tablets/3 capsules (Day 7). After Day 7, placebo matching both elpipodect and risperidone are respectively maintained at 3 tablets/3 capsules, QD for 3 weeks. |
Who may qualify
- Ages
- 18 to 50 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (11 listed)
- 18 to 50 years of age at Screening
- Male
- Female not of reproductive potential (e.g., postmenopausal or has had a hysterectomy), or agrees to practice abstinence or use acceptable contraception
- Meets the diagnostic criteria for schizophrenia according to the DSM-5 criteria, or has a past diagnosis of schizophrenia with the onset of the first episode being >=1 year prior to study entry, and has illness duration of <=20 years
- Is confirmed to be experiencing an acute episode of schizophrenia
Key exclusion criteria (17 listed)
- Is currently under involuntary commitment because he/she is considered a danger to himself/herself or others
- Is unwilling to remain hospitalized for the duration of trial treatment
- Is currently participating in or has participated in an interventional clinical research study <=6 months prior to Screening, or has participated in more than one interventional clinical trial research study within 12 months prior to Screening
- Is unwilling to allow audio/video taping of the Mini International Neuropsychiatric Interview for Schizophrenia and Psychotic Disorders (MINI) and/or PANSS interview at Screening and Baseline
- Is currently being treated with and benefiting from medications with a moderate or strong inhibiting or inducing effect on Cytochrome P450 (CYP) 3A and/or CYP2C9 and/or sensitive substrates of CYP2B6
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 CR tablets (4 mg) administered QD at the following dose strengths: 4 mg (1 tablet); 8 mg (2 tablets); 12 mg (3 tablets) | Drug | Elpipodect |
| RisperidoneOral capsules (2 mg) administered QD at the following dose strengths: 2 mg (1 capsule); 4 mg (2 capsules); 6 mg (3 capsules) | Drug | Risperidone |
| Placebo matching MK-8189Oral placebo tablet(s) matching the MK-8189 tablet, administered QD. | Drug | Placebo, Risperidone |
| Placebo matching risperidoneOral placebo capsule(s) matching the risperidone capsule, administered QD. | Drug | Elpipodect, Placebo |
Primary outcome
Least Squares Mean (LSM) Change From Baseline in the Positive and Negative Syndrome Scale (PANSS) Total Score at Week 4
Time frame: Baseline and Week 4
The LSM change from baseline at week 4 was assessed for PANSS total score. The PANSS assesses the severity of schizophrenia symptoms through a clinician-rated inventory of 30 items organized in 3 subscales: 1) positive subscale (7 items); 2) negative subscale (7 items); and 3) general psychopathology subscale (16 items). For each item, symptoms are scored from 1 (absent) to 7 (extreme) and sum to a total PANSS score (range: 30-210). Higher scores reflect more severe symptoms of schizophrenia. Further, reduced symptom severity over time is reflected by decreases in score.
Percentage of Participants Experiencing an Adverse Event (AE)
Time frame: Up to 6 weeks
The percentage of participants experiencing an AE was assessed. An AE is defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening of a preexisting condition that is temporally associated with the use of the Sponsor's product, is also an AE.
Percentage of Participants Discontinuing Study Treatment Due to an Adverse Event
Time frame: Up to 4 weeks
The percentage of participants discontinuing study treatment due to an AE was assessed. An AE is defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening of a preexisting condition that is temporally associated with the use of the Sponsor's product, is also an AE.
1 secondary outcome
Least Squares Mean (LSM) Change From Baseline in the Clinical Global Impression-Severity of Illness (CGI-S) Score at Week 4
Time frame: Baseline and Week 4
Results and safety
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.
- Results publication: PubMed 38851166Mukai Y, Lupinacci R, Marder S, Snow-Adami L, Voss T, Smith SM, Egan MF. Effects of PDE10A inhibitor MK-8189 in people with an acute episode of schizophrenia: A randomized proof-of-concept clinical trial. Schizophr Res. 2024 Aug;270:37-43. doi: 10.1016/j.schres.2024.05.019. Epub 2024 Jun 8.
- Individual participant dataSharing planned: No
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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
28 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Elpipodect and Risperidone in people with Schizophrenia, Acute Episode, run by Merck Sharp & Dohme LLC at 28 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 11 inclusion and 17 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 28 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. Some participants in this study may receive a placebo. 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 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
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 26 Dec 2018). 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?
Least Squares Mean (LSM) Change From Baseline in the Positive and Negative Syndrome Scale (PANSS) Total Score at Week 4 (time frame: Baseline and Week 4). 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 NCT03055338, which also lists 1 linked publication.
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.