Clinical Evaluation of Ropinirole CR-RLS ( SK&F101468)Tablets in Restless Legs Syndrome: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Clinical Evaluation of Ropinirole CR-RLS ( SK&F101468)Tablets in Restless Legs Syndrome (NCT00530790), a non-randomized phase 2 study. The primary outcome is Drug Related Adverse Events-On-Therapy.

2. Clinical Question

3. Trial Design

This was a Phase 2, single-group, non-randomized study of ropinirole controlled release in restless legs syndrome. The official title describes an open-label, uncontrolled study and classifies it as clinical pharmacology and exploratory. The record lists enrollment of 35 and an overall status of completed. Its listed start date is 2007-08-23, and its primary completion date is 2008-02-01. These dates describe the registry record; they do not supply details about the duration of each participant’s follow-up.

All participants were assigned to the ropinirole CR-RLS group, with no comparator arm identified. The arm description specifies oral, once-daily dosing timed before the onset of RLS symptoms and after 16:00. It describes dose adjustment beginning after the Week 1 visit and continuing through the Week 10 visit, but the available description is incomplete. The complete dosing and adjustment protocol is not reported in the registry record.

The design is useful for describing what was observed in a group receiving the study drug, including the safety experience recorded during treatment. It cannot separate treatment-associated changes from changes that might have occurred over time, expectation effects, or other influences, because there is no control group and no masking. The absence of random allocation also means the study does not provide a randomized treatment contrast.

The record lists 17 outcome measures and no analyses. It identifies a primary safety endpoint and a range of secondary measures, including symptom severity, clinical global ratings, sleep quality, quality of life, mood, anxiety, and depression. The record does not provide the statistical analysis plan, the analytic methods used for those outcomes, or posted numerical results for them. The planned sample-size justification and any interim-analysis plan are not 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.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Safety Population consisting of the subjects who took at least one dose of the 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.

6. Primary Endpoint

The registry lists the primary outcome as Drug Related Adverse Events-On-Therapy, measured over Weeks 1 - 12 Treatment Period.

The primary endpoint is titled “Drug Related Adverse Events-On-Therapy.” It is measured as a number of events over the Weeks 1–12 treatment period, for a safety population defined as participants who took at least one dose of study medication. This endpoint is intended to summarize drug-related adverse events recorded while participants were receiving treatment.

An event count is a way to describe the safety experience observed during a defined period. It differs from a measure that counts only whether each participant experienced at least one event: one participant may contribute more than one event, depending on the endpoint’s counting rules. The specific rules for identifying, coding, and counting drug-related events are not reported in the registry record. Nor does the record provide a posted numerical result for this primary endpoint.

Event counts can be informative for documenting the types and frequency of events recorded in a study, but they do not by themselves establish that a drug caused an event. In an uncontrolled, open-label study, there is no comparison group to contextualize the observed count, and attribution of an event as drug-related depends on the study’s assessment process. The number of events also needs to be interpreted alongside the number of participants at risk, observation time, event definitions, and completeness of follow-up. Those details are not fully reported in the registry record. The separately posted adverse-event figures describe affected participants, which should not automatically be treated as the primary endpoint’s total event count.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Several statistical ideas help clarify what this registry record can and cannot show. The explanations below are general unless they describe a feature explicitly listed in the registry record.

What does a single-group design estimate?

A single-group study observes outcomes among participants receiving the study intervention. It can describe what was recorded in that group over the study period. It does not directly estimate a treatment contrast, because a treatment contrast requires outcomes under the intervention to be compared with outcomes under a comparator. This study is listed as single-group and has no control arm. Therefore, the posted design cannot distinguish a treatment-associated change from other explanations such as natural symptom variation, changes over time, or the effects of study participation.

Randomization is a method for assigning participants to study groups in a way intended to reduce systematic differences between groups. This study is listed as non-randomized and has only one group, so it offers no randomized between-group comparison. Masking can reduce the influence of expectations on reporting and assessment; the record lists masking as none and describes the study as open-label. These design features do not invalidate a descriptive account, but they limit causal interpretation.

What does the primary endpoint count?

The primary endpoint is a count of drug-related adverse events during the Weeks 1–12 treatment period. A count outcome records how many events meet the endpoint definition. It is conceptually different from a participant-level indicator such as whether a participant experienced any event. A participant can potentially experience multiple events, so event totals and numbers of affected participants need not be the same. The registry’s adverse-event summary reports affected participants, while the primary endpoint is described as a number of events. They should not be treated as interchangeable.

For event-count analyses, the precise event definition, coding procedures, and rules for repeated events matter. Statistical models for counts may also need to account for over-dispersion, a general situation in which the observed variability is larger than a simple count model expects. This is a general methodological point; the analysis model and dispersion assumptions used for the primary endpoint are not reported in the registry record. No primary endpoint result is available in the registry record for this analysis.

Why does the observation period matter?

An event count depends in part on how long participants are observed and how consistently events are captured. A count over a fixed treatment period is not automatically comparable with a count from a different period or a group with different follow-up. Analyses may use exposure time or another adjustment when follow-up differs, but the registry record does not report whether that was done. The endpoint timeframe is specified as Weeks 1–12; further details about individual exposure and follow-up are not reported.

How should adverse-event summaries be read?

The adverse-event summary lists participants at risk and participants affected for serious events and other adverse events. “At risk” indicates the group against which the affected count is presented in the registry summary; it does not describe the severity or causality of each event. The reported affected counts are participant counts, not necessarily counts of all events. In the serious-event summary, 0 participants are listed as affected among 35 at risk. For other adverse events, 33 are listed as affected among 35 at risk. These descriptive figures do not, on their own, measure comparative risk or establish causation.

The deaths field is null, which signals that a numerical death count is not available in the record as presented. It should not be rewritten as zero. The record also lists no serious-event terms. Without those terms, event narratives, and assessment details, the types and circumstances of serious events cannot be characterized from this information.

What does a confidence interval ordinarily add?

In general, a confidence interval communicates the uncertainty around an estimated quantity under a statistical model. A narrower interval indicates greater precision for that estimate, while a wider interval indicates less precision. A confidence interval does not fix limitations in design: an interval around an uncontrolled group estimate would not create a randomized comparison or remove possible bias. No confidence interval or primary endpoint estimate is reported in the registry record.

What can be concluded from listed outcomes?

An outcome’s presence in a registry identifies a measure the study planned or recorded, but it is not itself a result. The record lists 17 outcome measures, including symptom, global impression, sleep, quality-of-life, mood, anxiety, and depression measures. It lists 0 analyses. Numerical findings, analytic populations for those outcomes, and methods such as adjustment or handling of repeated measurements are not reported in the registry record. As a result, no effect estimate or precision assessment for these outcomes can be presented.

The record includes sample-size assumptions for a planning illustration based on an observed effect, with two-sided significance level 0.05, equal allocation between two arms, and a normal approximation. This is a generic planning setup rather than an analysis of the single-group study design. No numerical planning results are available in the registry record for this analysis. Any such sample-size illustration would concern planning a future comparison; it would not be observed power or evidence that the current study detected an effect.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 17 outcome measures, including the primary safety endpoint and secondary measures addressing RLS symptoms, clinical global impressions, sleep, quality of life, mood, anxiety, and depression. When a study assesses many outcomes, the chance of at least one apparently notable result can increase if each is tested separately without accounting for the number of comparisons. This is a general statistical issue known as multiplicity. It does not mean that a result is necessarily misleading; it means that interpretation depends on which outcomes were prespecified, how tests were organized, and whether any adjustment or hierarchy was used.

The statistical plan, any multiplicity-control procedure, and the analysis methods for the listed outcomes are not reported in the registry record. The record lists 0 analyses, and the registry entries contain no numerical results for the secondary outcomes. It is therefore not possible to assess whether reported inferences account for multiple outcomes or to compare estimates across outcomes.

Missing-data methods are also not reported in the registry record. The record does not describe how incomplete assessments, withdrawals, or missed visits were handled, nor does it provide outcome-specific analysis populations or participant flow. These details matter because results can depend on who contributes data and how missing observations are treated. The safety population is defined as participants who took at least one dose of study medication, but that definition does not specify the analysis population for each secondary measure.

There is no reported interim-analysis plan, and the planned sample-size justification is not reported in the registry record. Without these details, the intended statistical decision process and the handling of incomplete data cannot be reconstructed from the record.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry’s adverse-event summary lists 0 participants affected by serious adverse events among 35 at risk. For other adverse events, it lists 33 participants affected among 35 at risk. These figures describe affected participants in the posted safety summary; they are not the same measure as the primary endpoint, which is defined as the number of drug-related adverse events during the Weeks 1–12 treatment period. The primary endpoint’s result is not reported in the registry record.

The terms “serious” and “other” identify categories in the adverse-event summary, but the record does not provide serious-event terms or details about the other events. It does not report the methods used to judge whether an event was drug-related. The deaths field is null, so a death count is not reported in the registry record; null should not be read as zero.

These counts are descriptive and come from a single-group, open-label study. They do not compare event experience with an untreated or alternative-treatment group, and they do not establish that ropinirole caused or prevented an event. Further interpretation would require event-level definitions, follow-up and exposure details, and the study’s assessment procedures, which are not reported in the registry record.

12. What the Result Does, and Does Not, Mean

The record establishes that a Phase 2 study evaluated ropinirole controlled release in people with restless legs syndrome using an open-label, uncontrolled, single-group design. It identifies the primary endpoint as a count of drug-related adverse events during the Weeks 1–12 treatment period and lists a safety population of participants who took at least one dose. The adverse-event summary reports 0 participants affected by serious events among 35 at risk and 33 affected by other events among 35 at risk. Those are descriptive safety figures, not a comparison of treatments.

The record does not report the numerical result for the primary endpoint. It also does not provide numerical results for the listed secondary outcomes. The outcome list signals that symptoms, global impressions, sleep, quality of life, mood, and anxiety or depression were among the study measures, but it does not indicate what the results were. No efficacy effect estimate, uncertainty interval, or comparison with another treatment can be derived in the registry record for this analysis.

Even if changes in an outcome had been reported, the design would not establish that treatment caused those changes. There was no control group, randomization, or masking. In general, an uncontrolled study can describe observations in its treatment group, but cannot show how those observations compare with what would have happened under another treatment or without treatment. Open-label assessment can also be influenced by expectations; the extent of any such influence in this study is not reported.

The adverse-event counts likewise do not establish causation or comparative safety. The summary distinguishes affected participants from the primary event-count endpoint, and details of event definitions and relatedness assessments are not reported. The null deaths field does not provide a numerical death count.

Accordingly, the record is best read as a description of an exploratory, uncontrolled study and selected safety-summary counts. It does not support a claim that ropinirole is effective or ineffective, nor does it establish that the recorded adverse events were caused by treatment. Those questions require interpretable outcome results and a design and analysis that support the relevant comparisons.

13. Why This Trial Matters Statistically

This trial matters statistically because it illustrates the difference between documenting outcomes and estimating a treatment effect. The registry identifies a specific treatment, a population with restless legs syndrome, and a primary safety endpoint. Those details clarify what the study set out to observe. But the single-group, non-randomized, open-label design has no concurrent control, so the study cannot estimate a randomized contrast between ropinirole and another option.

It also illustrates why the endpoint’s unit matters. The primary endpoint is a number of drug-related adverse events, whereas the separate adverse-event summary reports affected participants. Event counts and participant counts answer different questions and can differ when participants experience multiple events. Reading them as equivalent would misstate what the record reports.

The safety summary is informative as a description of observed participants: it lists serious-event and other-event affected counts with their at-risk counts. At the same time, the missing primary endpoint result, the null deaths field, and the absence of event terms constrain interpretation. A numerical count without details about exposure, event definitions, and attribution cannot answer every safety question.

Finally, the record lists a broad set of secondary outcomes but no analyses. This highlights a central principle in registry interpretation: an outcome list is not evidence of a result. Statistical conclusions depend on estimates, uncertainty, analysis populations, missing-data handling, and prespecified methods. Those details are not reported in the registry record. The trial therefore provides a useful example of how design, endpoint definition, and completeness of reporting shape the strength of statistical 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.

Several limitations specific to this study affect interpretation. It is listed as single-group, non-randomized, and unmasked, and the official title describes it as open-label and uncontrolled. There is no comparator against which to judge the adverse-event experience or changes in symptoms and other outcomes. Consequently, observed changes cannot be separated from time trends, expectations, or other influences using this design.

The primary endpoint is defined as a number of drug-related adverse events during Weeks 1–12, but its numerical result is not reported in the registry record. The adverse-event summary instead gives affected-participant counts: 0 for serious events and 33 for other events, each among 35 at risk. Those figures do not replace the missing primary event count. Serious-event terms are not listed, and the deaths field is null rather than a reported count.

The record lists 17 outcome measures and 0 analyses, but no numerical results for the secondary outcomes are included in the registry record for this analysis. Statistical methods, multiplicity handling, missing-data procedures, and outcome-specific analysis populations are not reported in the registry record. These gaps prevent assessment of precision, robustness, and the possible effects of incomplete observations.

The available arm description is incomplete: it identifies the general dosing schedule and describes adjustment through the Week 10 visit, but does not give the complete adjustment instructions. Detailed eligibility criteria, participant characteristics, individual exposure, and follow-up completeness are also not reported in the registry record. The study’s planned sample-size justification and any interim-analysis plan are not reported. Together, these limitations leave the record most suitable for describing the study framework and the adverse-event summary, rather than drawing comparative or causal conclusions.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Clinical Evaluation of Ropinirole CR-RLS ( SK&F101468)Tablets in Restless Legs Syndrome — NCT00530790.
• Registry record last updated 2018-09-26; status last verified 2018-08.
• Results first posted 2009-07-24.
• 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.

18. Record Summary

The registry record describes a completed Phase 2 study of ropinirole controlled release in restless legs syndrome. It was open-label, uncontrolled, non-randomized, and single-group, with enrollment of 35. The listed primary endpoint was the number of drug-related adverse events during the Weeks 1–12 treatment period among participants who took at least one dose.

The adverse-event summary lists 0 participants affected by serious events among 35 at risk and 33 affected by other adverse events among 35 at risk. The primary endpoint’s numerical result is not reported in the registry record, and the deaths field is null. The record lists 17 outcome measures and 0 analyses; numerical results for secondary outcomes are not available in the registry record used for this account.

Because there was no comparator, randomization, or masking, the study supports descriptive interpretation only. It does not establish a treatment effect or comparative safety.