Adults 30 to 85, any sex, with Parkinson Disease or Idiopathic Parkinson Disease. Patients with the condition only — healthy volunteers not accepted.
Results — posted to ClinicalTrials.gov
Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.
Change From Baseline in Average "Off" Time (Hours Per Day) at Week 12Primary· Baseline and Week 12
The "on" state is defined as the period of time during which a patient's symptoms of PD improve or disappear following treatment with L-dopa or dopamine agonists. The "off" state is defined as the period of time characterized by the return of symptoms (i..e. tremor, slowness, and rigidity) following treatment with L-dopa or dopamine agonists. Study participants reported their symptoms at half-hour intervals as "off", "on", or "asleep" on their daily diary for 3 days before randomization (baseline) and for the 3 days immediately before their Week 12 visit. The mean change from baseline in "off"
Group
Value
95% CI
Preladenant 2 mg
-1.0
± 0.20
Preladenant 5 mg
-1.1
± 0.20
Placebo
-0.8
± 0.19
Percentage of Participants With >30% Change (Reduction) From Baseline at Week 12 in Mean "Off" TimeSecondary· Baseline and Week 12
A participant with at least a 30% reduction in mean "off" time from Baseline to End of Treatment (Week 12) is considered as "responder". The "on" state is defined as the period of time during which a patient's symptoms of PD improve or disappear following treatment with L-dopa or dopamine agonists. The "off" state is defined as the period of time characterized by the return of symptoms (i..e. tremor, slowness, and rigidity) following treatment with L-dopa or dopamine agonists. Study participants reported their symptoms at half-hour intervals as "off", "on", or "asleep" on their daily diary for
Group
Value
95% CI
Preladenant 2 mg
37.1
Preladenant 5 mg
36.9
Placebo
30.5
Change From Baseline in Average "On" Time (Hours Per Day) Without Troublesome Dyskinesia at Week 12Secondary· Baseline and Week 12
"On" time is when a PD participant's symptoms are improved. Mean "on" time without troublesome dyskinesias is derived from the available diary data collected for 3 days immediately prior to a clinic visit. "On" time without troublesome dyskinesia is the sum of "on" time without dyskinesia plus "on" time with non-troublesome dyskinesia as recorded in the diary. The mean change from baseline in "on" time was based on a cLDA with treatment, time, and treatment-by-time interaction as fixed effects and subject as random effect.
Group
Value
95% CI
Preladenant 2 mg
0.6
± 0.21
Preladenant 5 mg
0.7
± 0.21
Placebo
0.5
± 0.20
Number of Participants With Systolic Blood Pressure (SBP) ≥180 mmHg and 20 mmHg IncreasePrimary· Up to Week 14
The number of participants with Systolic Blood Pressure (SBP) ≥180 mmHg and 20 mmHg increase was reported. Participants lie supine at rest for 5 minutes, then have a single BP measurement taken (ie, 1 reading). Participants then stand for 3 minutes at rest, followed by a single BP measurement (1 reading) in the standing position.
Supine
Group
Value
95% CI
Preladenant 2 mg
0
Preladenant 5 mg
1
Placebo
0
Standing
Group
Value
95% CI
Preladenant 2 mg
1
Preladenant 5 mg
0
Placebo
0
Number of Participants With Diastolic Blood Pressure (DBP) ≥105 mmHg and 15 mmHg IncreasePrimary· Up to Week 14
The number of participants with Diastolic Blood Pressure (DBP) ≥105 mmHg and 15 mmHg increase was reported. Participants lie supine at rest for 5 minutes, then have a single BP measurement taken (ie, 1 reading). Participants then stand for 3 minutes at rest, followed by a single BP measurement (1 reading) in the standing position.
Supine
Group
Value
95% CI
Preladenant 2 mg
1
Preladenant 5 mg
2
Placebo
3
Standing
Group
Value
95% CI
Preladenant 2 mg
7
Preladenant 5 mg
3
Placebo
6
Percentage of Participants With SuicidalityPrimary· Up to Week 12
The percentage of participants with suicidality using the Columbia - Suicide Severity Rating Scale (C-SSRS) was reported. The C-SSR was used in this study only for the purpose of safety monitoring by measuring the incidence of different types of suicidality categories during treatment. The assessment was done by the nature of the responses, not by a numbered scale. Participants who reported at least one occurrence of suicidal behavior or suicidal ideation were counted as having experienced suicidality. Suicidal behavior included suicide attempt, aborted attempt, interrupted attempt, or prepara
Group
Value
95% CI
Preladenant 2 mg
3
Preladenant 5 mg
4
Placebo
1
Change From Baseline in Total Epworth Sleepiness Scale (ESS) at Week 12Primary· Baseline and Week 12
The ESS is a self-administered questionnaire providing a measure of a person's general level of daytime sleepiness, or their average sleep propensity in daily life. The scale consists of 8 situations in which the participant rates their tendency to become sleepy on a scale of 0=no chance of dozing to 3=high chance of dozing. The overall score is the sum of the scores for the 8 situations for a minimum of 0 and a maximum of 24 with a higher score indicating greater sleepiness. The mean change from baseline in total EES was based on a cLDA with treatment, time, and treatment-by-time interaction
Group
Value
95% CI
Preladenant 2 mg
-0.4
± 0.28
Preladenant 5 mg
-0.0
± 0.29
Placebo
-0.2
± 0.28
Adverse events — posted to ClinicalTrials.gov
Time frame: Up to 14 weeks (including 14 days of follow-up).
Reporting threshold: 5%.
Adverse-event reports describe events observed during the trial — not all are caused by the drug.
This is a study of the efficacy and safety of preladenant in adult participants with moderate to severe Parkinson's Disease (PD). While on this study, participants will continue to take their usual, prescribed, stable regimen of levodopa (L-dopa) or L-dopa plus adjunct PD medications and will be randomized to receive 2 mg preladenant, 5 mg preladenant, or placebo, twice daily, for 12 weeks. After that, participants may choose to receive additional treatment with preladenant. The primary hypothesis is that at least the 5 mg twice daily dose of preladenant is superior to placebo as measured by the change from Baseline to Week 12 in the mean "off" time.
Publications & conference data
8 peer-reviewed publications reference this trial (live from Europe PMC):
NCT01465412 — A Study to Assess Pharmacokinetics of Preladenant in Participants With Chronic Hepatic Impairment (P06513)
· Phase 1
· completed
NCT01323855 — A Study to Assess Pharmacokinetics (PK) of Preladenant in Participants With Chronic Renal Impairment (CRI) (P06512)
· Phase 1
· completed
NCT01294800 — A Dose Finding Study of Preladenant (SCH 420814) for the Treatment of Parkinson's Disease (PD) in Japanese Patients (P06
· Phase 2
· completed
NCT01215227 — An Active-Controlled Extension Study to NCT01155466 [P04938] and NCT01227265 [P07037] (P06153)
· Phase 3
· terminated
NCT00537017 — Follow Up Safety Study of SCH 420814 in Subjects With Parkinson's Disease (P05175)
· Phase 2
· completed
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Publications: Europe PMC API search by NCT ID, retrieved 10 June 2026
Drug + disease cross-links: matched in real time against Drug Landscape's normalised drug + company + condition tables
Sponsor: as reported to ClinicalTrials.gov by Merck Sharp & Dohme LLC
Last refreshed: 24 September 2018
Drug Landscape aggregates and links these public records for informational use only. Always verify against the primary source before clinical or regulatory decisions. Canonical URL: https://druglandscape.com/trial/NCT01227265.