This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for An Open-label Continuation Study Evaluating the Long-term Safety of Extended Release Ropinirole XL (Formerly CR) in Parkinson''s Disease (NCT00632736), a non-randomized phase 3 study. The primary outcome is Number of Participants With the Indicated Number of Adverse Events (AEs) and Serious Adverse Events (SAEs).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00632736 |
| Phase | Phase 3 |
| Condition | Parkinson Disease, Parkinson's Disease |
| Allocation | Non-Randomized |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 419 |
| Arms in the primary outcome | n/a |
| Lead sponsor | GlaxoSmithKline |
| Results posted | Yes |
2. Clinical Question
Population
The safety population comprised participants with early or advanced Parkinson’s disease who received at least one dose of study medication. The registry reports 419 participants at risk for both serious and other adverse events. The study was an extension for participants from studies 101468/165, 101468/168 and 101468/169; further eligibility details are not reported in the registry record.
Intervention
Participants received ropinirole XL, formerly described as CR. The stated purpose was to evaluate its safety profile during long-term treatment. The record describes an open-label study and does not specify a dose or dosing schedule in the information reported for these results.
Comparator
There was no concurrent comparator group: the study used a non-randomized, single-group design. The posted results therefore describe adverse events among participants receiving ropinirole XL; they do not provide a like-for-like comparison with another treatment or with no treatment.
Primary question
The primary outcome counted participants with adverse events and serious adverse events during the stated collection period, 13 February 2004 through 31 March 2010. The key question is descriptive: how many participants in the safety population were recorded as having these events during long-term treatment? This outcome addresses safety reporting, not whether ropinirole XL improves Parkinson’s disease symptoms.
3. Trial Design
This was a Phase 3, open-label extension study of ropinirole XL, formerly CR, in participants with early and advanced Parkinson’s disease. It was non-randomized and used a single-group model, so participants were not assigned at random to different treatment groups and there was no concurrent control group. The registry identifies the study as completed and reports enrollment of 419.
The study’s stated aim was to evaluate the safety profile of ropinirole XL during long-term treatment. The recorded primary outcome was the number of participants with adverse events and serious adverse events. The safety population is defined as all participants who received at least one dose of study medication. The outcome’s collection timeframe was 13 February 2004 through 31 March 2010. The registry also lists patient preference response at week 4 and week 26 as a secondary outcome, but does not report those results in the information available for this analysis.
The study is described as an extension for participants from studies 101468/165, 101468/168 and 101468/169. The record does not report how participants entered the extension, the treatment duration for each participant, or whether all participants had the same follow-up. Start and primary completion are recorded as 2004-02 and 2010-03. These dates identify the study’s overall recorded timeline, not the duration of an individual participant’s treatment.
Because the design had no randomized comparator and no masking, its adverse-event counts are descriptive. They can show what was recorded among participants treated in this study, but cannot isolate the contribution of treatment from other influences or support a direct treatment comparison. No protocol details beyond those stated are reported in the registry record.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Before assignment: Study 101468/248 (this study, NCT00632736) was an open-label extension study with ropinirole extended release (XL) for subjects from studies 101468/165, 101468/168, and 101468/169 (NCT00381472).
Overall Study
| Stage | Ropinirole XL |
|---|---|
| STARTED | 419 |
| COMPLETED | 151 |
| NOT COMPLETED | 268 |
Reasons for not completing this period:
| Reason | Ropinirole XL |
|---|---|
| Adverse Event | 104 |
| Lost to Follow-up | 15 |
| Protocol Violation | 14 |
| Withdrawal by Subject | 99 |
| Lack of Efficacy | 5 |
| Sponsor terminated study | 5 |
| Non-compliance | 10 |
| Other | 16 |
Analysis population for the primary outcome, as defined in the registry: Safety Population: all participants who received at least one dose of study medication
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | Ropinirole XL |
|---|---|---|
| Participants analysed | 419 | |
| Age, Continuous | Years | 64.3 (SD 9.81) |
| Sex: Female, Male: Female | Participants | 160 |
| Sex: Female, Male: Male | Participants | 259 |
| Race/Ethnicity, Customized: White/Caucasian | participants | 409 |
| Race/Ethnicity, Customized: American Hispanic | participants | 5 |
| Race/Ethnicity, Customized: Black | participants | 2 |
| Race/Ethnicity, Customized: Arabic/North African | participants | 0 |
| Race/Ethnicity, Customized: East & South East Asian | participants | 2 |
| Race/Ethnicity, Customized: South Asian | participants | 0 |
| Race/Ethnicity, Customized: Unknown | participants | 1 |
| Body Mass Index (BMI) | kilograms per square meters (kg/m^2) | 26.5 (SD 4.48) |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants With the Indicated Number of Adverse Events (AEs) and Serious Adverse Events (SAEs), measured over 13 February 2004 through 31 March 2010.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | participants |
| Endpoint classification | Binary Endpoint |
The primary outcome counts participants with adverse events and serious adverse events. An adverse event is defined in the registry as an unfavorable and unintended sign, symptom, or disease temporally associated with use of a medicinal product. A serious adverse event is an event that is fatal, life threatening, disabling or incapacitating, results in hospitalization or prolongs a hospital stay, involves a congenital abnormality or birth defect, or is considered an important medical occurrence that the investigator regards as serious based on medical judgment.
These categories are used to describe safety and tolerability during exposure. Reporting participant counts conveys how many people were recorded as affected, rather than the total number of event episodes. The posted results list 109 participants with serious adverse events and 261 with other adverse events, each among 419 at risk in the respective category. These categories should not be assumed to be mutually exclusive: the registry record does not say whether participants could appear in both.
The endpoint is a safety measure, not a measure of symptom improvement or treatment benefit. It also does not, by itself, establish that a reported event was caused by ropinirole XL. The registry describes events as temporally associated with medicinal-product use, while causal attribution requires information and analysis beyond a count.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted results are counts from a single treatment group. The registry reports 109 participants with serious adverse events and 261 participants with other adverse events; 419 participants are listed as at risk for each category. These figures describe what was recorded in the safety population over the stated collection period. They are not treatment effects, and there is no randomized comparison from which to estimate a difference between ropinirole XL and another treatment.
Seriousness is defined by the event’s consequences or clinical significance, not simply by how often an event occurs. The registry’s criteria include events that are fatal, life threatening, disabling or incapacitating, result in or prolong hospitalization, involve a congenital abnormality or birth defect, or are judged important by the investigator. The category of other adverse events is reported separately. The record does not give additional detail about how participants with events in both categories were handled, so the counts should not be combined or treated as mutually exclusive.
The listed serious adverse-event terms include Parkinson’s Disease (2.9%), Pneumonia (1.7%), Angina pectoris (1.2%), Coronary artery disease (1.0%), Back pain (1.0%) and Dyskinesia (0.7%). These are the registry’s listed terms and percentages; the record does not provide further detail in this summary about the denominator or the method used to derive each percentage. The figures should therefore be read as reported, without using them to infer a comparative risk or a causal relationship.
There are no analysis results listed in the registry record. In particular, it does not report a model-based estimate, confidence interval, hypothesis test, or adjustment for potential differences in follow-up. A confidence interval, in general, describes the statistical uncertainty around an estimated quantity; without an estimate and its interval, precision cannot be assessed in that way. The counts alone do not indicate how precisely a treatment-related effect has been estimated.
The long collection period is consistent with the study’s stated long-term safety aim, but it does not mean that every participant was observed for the entire period. Individual follow-up durations and time at risk are not reported in the registry record. Without those details, the counts cannot be interpreted as rates per unit of exposure or used to compare event frequency across differing follow-up periods.
The results are thus best understood as descriptive safety reporting among participants who received at least one dose. They do not establish that ropinirole XL caused the reported events, nor do they establish that an event would have occurred at a different frequency under another treatment. The non-randomized, single-group design is central to that limitation.
9. Statistical Methods Explained
The primary outcome is reported as the number of participants with adverse events and serious adverse events. For a binary safety outcome, each participant can be classified according to whether an event meeting the definition was recorded. A count communicates how many participants were classified as having an event; it is not the same as a count of all event episodes. The registry describes the outcome unit as participants and the event interpretation as participants with an event.
What can a participant count establish?
A participant count provides a direct descriptive summary within the population under observation. In this record, the serious adverse-event count is 109 and the other adverse-event count is 261, with 419 at risk in each category. These figures support statements about recorded participants in this study. They do not by themselves estimate a treatment contrast, since the study has no comparator group. They also do not show how event timing, recurrence, or exposure duration varied across participants.
In general, a rate can account for different amounts of time at risk by relating events to person-time. That approach requires individual or aggregate exposure-time information, which is not reported in the registry record. A participant count and an exposure-adjusted rate answer different questions; the former concerns the number of participants recorded with events, while the latter incorporates time under observation. No exposure-adjusted rate is reported.
Why does the design matter for interpretation?
Randomization is a general design method for making treatment groups comparable, on average, with respect to both measured and unmeasured factors. This trial was non-randomized and single-group, so it does not use that protection to support a treatment comparison. An observed event may be related to the underlying disease, other circumstances, study medication, or more than one influence. The counts cannot separate these possibilities.
Masking is another general design feature that can reduce the influence of expectations on care, assessment, or reporting. The registry lists masking as none and describes the study as open-label. This is relevant to interpretation of reported events, especially where recognition, reporting, or investigator judgment plays a role. The record does not describe procedures used to limit such influences.
What does a confidence interval add?
In general, a confidence interval expresses the uncertainty associated with an estimate under a statistical model and its assumptions. It is not a measure of the probability that a particular hypothesis is true. An interval around a treatment contrast can indicate which effect sizes are compatible with the observed data and model. The registry record lists no analysis results for this outcome, so no confidence interval or model-based estimate is available to interpret.
Likewise, a hypothesis test addresses compatibility between data and a specified null hypothesis under stated assumptions. It does not measure clinical importance or establish causality. No hypothesis-test result is reported for the primary outcome. A missing test result should not be read as evidence that the groups were equivalent; there are no randomized groups in this study to compare in the first place.
How should planning illustrations be read?
Sample-size calculations are planning tools, not findings from an enrolled study. The registry describes a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. Such assumptions describe a hypothetical planning exercise, not the design used in this single-group extension. The registry record does not report the trial’s own sample-size justification or provide a basis for treating any planning value as observed power.
In general, power is a design property under specified assumptions about an effect, variability, significance level, and analysis. It is not a retrospective measure of whether a result is reliable. A calculation that uses an observed effect as its input is particularly dependent on that effect and its uncertainty. It should not be interpreted as proof that the study had adequate power or that a nonsignificant result would demonstrate no effect. No inferential result is listed, and no observed power is reported.
Why can event counts be incomplete descriptions?
Adverse events may differ in severity, duration, recurrence, timing, and clinical context. A summary count does not preserve all those distinctions. In general, detailed safety interpretation may consider event definitions, exposure, time to event, participant-level overlap, and how events were coded. The registry gives definitions and selected serious-event terms, but it does not report all such details in the record summarized for this outcome. It also does not report a time-to-event analysis or an analysis accounting for differing follow-up.
Over-dispersion is a general issue when event counts vary more than a statistical model expects; it can make uncertainty estimates too small if the model assumes less variation than the data contain. That issue is most directly relevant to analyses of event counts or rates. The primary outcome is presented as the number of participants with an event, and no count model or dispersion estimate is reported. It would therefore be inappropriate to claim that over-dispersion was tested or corrected for in this trial.
10. Multiplicity, Missing Data and Analysis Populations
The registry identifies the participant count for adverse events and serious adverse events as the primary outcome and lists a patient preference response at week 4 and week 26 as a secondary outcome. The posted results summarized for the primary outcome do not include an analysis plan, inferential tests, or a multiplicity procedure. The registry record does not report whether statistical testing was planned across outcomes or how any family of tests would have been handled.
Multiplicity is a general concern when many outcomes, time points, subgroups, or comparisons are tested: the chance of finding at least one apparently notable result can increase as tests accumulate. Methods such as adjustment or a prespecified testing hierarchy can address particular multiplicity concerns. Their appropriateness depends on the questions and analysis plan. No such procedure is reported in the registry record, so no claim about control of false-positive findings can be made.
Missing-data handling is also not reported. The safety population is defined as participants who received at least one dose, but the record does not describe how incomplete follow-up, withdrawal, unavailable event information, or differing observation time were handled. It does not report the number of participants with missing outcome information. Consequently, the reported counts should be interpreted as registry-recorded counts, not as evidence that all participants were observed equally or that missing information had no effect.
The record names a safety population but does not report a separate analysis population, participant-level exclusions, or a statistical analysis set. It also does not report interim analyses or a detailed statistical plan. These absences do not establish that a procedure was or was not performed outside the registry entry; they mean the relevant details are not reported in the registry record.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Ropinirole XL | 109 | 419 | 26.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Ropinirole XL | 261 of 419 |
Most frequent serious adverse event terms
| Event term | Organ system | Ropinirole XL |
|---|---|---|
| Parkinson's Disease | Nervous system disorders | 12 of 419 |
| Pneumonia | Infections and infestations | 7 of 419 |
| Angina pectoris | Cardiac disorders | 5 of 419 |
| Coronary artery disease | Cardiac disorders | 4 of 419 |
| Back pain | Musculoskeletal and connective tissue disorders | 4 of 419 |
| Dyskinesia | Nervous system disorders | 3 of 419 |
| Fall | Injury, poisoning and procedural complications | 3 of 419 |
| Osteoarthritis | Musculoskeletal and connective tissue disorders | 3 of 419 |
| Psychotic disorder | Psychiatric disorders | 3 of 419 |
| Urinary retention | Renal and urinary disorders | 3 of 419 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Ropinirole XL |
|---|---|---|
| Back pain | Musculoskeletal and connective tissue disorders | 58 of 419 |
| Hallucination | Psychiatric disorders | 54 of 419 |
| Oedema peripheral | General disorders | 48 of 419 |
| Somnolence | Nervous system disorders | 47 of 419 |
| Dyskinesia | Nervous system disorders | 35 of 419 |
| Insomnia | Psychiatric disorders | 31 of 419 |
| Headache | Nervous system disorders | 27 of 419 |
| Nausea | Gastrointestinal disorders | 27 of 419 |
| Dizziness | Nervous system disorders | 23 of 419 |
| Parkinson's Disease | Nervous system disorders | 23 of 419 |
Serious events with the highest arm-level rate: parkinson's disease (2.9%), pneumonia (1.7%), angina pectoris (1.2%), coronary artery disease (1.0%), back pain (1.0%).
The safety outcome lists 109 participants with serious adverse events and 261 with other adverse events. The registry reports 419 at risk for each category. The counts concern participants recorded as affected, not the total number of event episodes. They should not be added: the record does not establish that the categories are mutually exclusive or explain whether a participant could be counted in both.
The serious adverse-event definition includes events that are fatal, life threatening, disabling or incapacitating, result in hospitalization or prolong a hospital stay, involve a congenital abnormality or birth defect, or are deemed important by the investigator based on medical judgment. The registry lists Parkinson’s Disease (2.9%), Pneumonia (1.7%), Angina pectoris (1.2%), Coronary artery disease (1.0%), Back pain (1.0%) and Dyskinesia (0.7%) among the serious terms. The death count is not reported in the registry record.
These figures describe events recorded during the stated collection period. They do not show that treatment caused an event, and they do not permit comparison with an untreated group or another therapy. Individual exposure time and follow-up are not reported, so the counts should not be read as exposure-adjusted rates.
12. What the Result Does, and Does Not, Mean
The result gives a descriptive account of adverse events recorded among participants receiving ropinirole XL in this extension study. It establishes that the registry recorded 109 participants with serious adverse events and 261 with other adverse events, among 419 at risk for each category. It also identifies selected serious-event terms and their listed percentages. These are observations from the study population, not estimates of a treatment effect.
The result does not establish that ropinirole XL caused the events. An event may occur during treatment without being caused by treatment, and the registry definition itself describes temporal association rather than certainty of causation. Without a concurrent comparator and a design that supports causal attribution, these counts cannot distinguish treatment-related events from events associated with Parkinson’s disease, other health conditions, or other influences.
The result also does not establish how the event experience would compare under another treatment, or with no treatment. There was no randomized comparison group. Nor do the counts show how many event episodes occurred, how long events lasted, whether they recurred, or when they arose relative to treatment. Individual exposure and follow-up durations are not reported in the registry record.
No inferential analysis, confidence interval, or hypothesis test is listed. Therefore the precision of a treatment-related estimate cannot be evaluated, and no conclusion about equivalence or absence of risk follows from the lack of a comparative result. The registry’s planning assumptions do not substitute for an analysis of this single-group safety outcome and do not represent observed power.
The appropriate interpretation is bounded: the posted results summarize participants recorded with safety events during long-term treatment in an open-label extension. They can inform a descriptive account of what was reported in this study, while leaving comparative risk, causality, and the effect of differing follow-up unresolved. The registry record does not report enough detail to answer those additional questions.
13. Why This Trial Matters Statistically
This study is statistically informative because it illustrates the role and limits of descriptive safety data. A long-term safety question can be addressed by recording adverse events during treatment, and participant counts provide an accessible summary of how many people were recorded as affected. The distinctions between adverse events and serious adverse events also show why event definitions matter: a serious event is classified by specified consequences or clinical judgment, not merely by frequency.
At the same time, the single-group, non-randomized design defines what can be learned from those counts. Without a comparator, there is no direct estimate of how event occurrence differs under another treatment. Without masking, event identification and reporting may be influenced by awareness of treatment, although the registry does not report whether this occurred. These are design considerations, not evidence that the recorded events are inaccurate.
The registry’s description also highlights why a participant count is not interchangeable with an event rate. Counts do not account for how long each participant was followed or exposed. The overall collection period extends from 13 February 2004 through 31 March 2010, but the record does not say that participants had the same observation period. Time-at-risk information would be needed to interpret exposure-adjusted frequency.
Finally, the absence of reported analysis results constrains statistical interpretation. Without estimates, confidence intervals, tests, or a detailed analysis plan, the record supports description rather than claims about comparative effects or statistical precision. This is an important distinction in clinical research: a safety summary may be useful for characterizing recorded events while remaining insufficient for causal or comparative conclusions.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The main limitation is the absence of a comparator. This was a non-randomized, single-group, open-label study, so the recorded event counts cannot establish how safety outcomes would differ under another treatment or no treatment. The design also cannot, by itself, separate events associated with treatment from events related to Parkinson’s disease or other influences.
The registry defines the safety population as participants who received at least one dose, but does not report participant-level exposure duration, follow-up completeness, or time at risk. The overall event collection period is stated as 13 February 2004 through 31 March 2010; that does not describe each participant’s observation time. As a result, the counts cannot be interpreted as exposure-adjusted rates.
The record reports participant counts for serious and other adverse events but does not explain whether participants could be included in both categories, how repeated events were handled, or how missing event information was managed. It lists selected serious-event terms and percentages without further details in this summary about their denominators or calculation method. The death count is not reported in the registry record.
No analysis results, confidence intervals, hypothesis tests, or detailed statistical plan are reported. The registry also does not report the sample-size justification, interim analyses, multiplicity handling, or statistical methods for the primary outcome. The planning assumptions described for sample-size illustrations do not represent the single-group study’s design or observed power. These omissions limit the assessment of precision, analysis choices, and robustness beyond the descriptive counts.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: An Open-label Continuation Study Evaluating the Long-term Safety of Extended Release Ropinirole XL (Formerly CR) in Parkinson''s Disease — NCT00632736.
- Registry record last updated 2017-03-23; status last verified 2017-03.
- Results first posted 2010-12-24.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT00632736 is a completed Phase 3, open-label extension study of ropinirole XL, formerly CR, in participants with early and advanced Parkinson’s disease. It was non-randomized and single-group, with enrollment of 419. The stated aim was to evaluate long-term safety. The safety population included participants who received at least one dose of study medication.
The primary outcome counted participants with adverse events and serious adverse events during 13 February 2004 through 31 March 2010. The registry reports 109 participants with serious adverse events and 261 with other adverse events, with 419 at risk for each. It lists selected serious-event terms and percentages, but no analysis results. A patient preference response at week 4 and week 26 is listed as a secondary outcome; results are not reported in the registry record.
The single-group design supports descriptive reporting, not a randomized comparison. Individual follow-up, missing-data handling, and a detailed statistical analysis plan are not reported in the registry record.