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 Extended Niacin/Laropiprant in Patients With Type 2 Diabetes (0524A-069) (NCT00485758), a randomized phase 3 study. The primary outcome is Percent Change at Week (Wk) 12 Compared to Baseline (Bl) in Low-density Lipoprotein Cholesterol in Patients With Type 2 Diabetes When Compared to Placebo.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00485758 |
| Phase | Phase 3 |
| Condition | Diabetes Mellitus Type 2 |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 796 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Merck Sharp & Dohme LLC |
| Results posted | Yes |
2. Clinical Question
Population
Patients with type 2 diabetes were included. The primary endpoint is described for the Full Analysis Set. The registry record does not give further eligibility details or define the Full Analysis Set in the posted results.
Intervention
The treatment was extended-release niacin/laropiprant. The description says participants began with one tablet of ER niacin/laropiprant (1g) alongside one tablet of their run-in statin dose, advancing to ER niacin/laropiprant (2g) at Week 4 for the remainder of the study.
Comparator
The comparator was placebo ER niacin/laropiprant, added in week 4 to a stable lipid-modifying regimen for the duration of the study. The registry record does not specify the placebo formulation.
Primary question
The primary question was whether the treatment groups differed in percent change from baseline in low-density lipoprotein cholesterol at Week 12. The endpoint description frames this as an assessment of LDL cholesterol reduction in patients with type 2 diabetes compared with placebo. The registry also lists week 12 percent change in high-density lipoprotein cholesterol and triglycerides as secondary outcomes, but their results are not included in the posted data.
3. Trial Design
This was a phase 3, randomized, double-blind, parallel-group, placebo-controlled study. Its official title describes a 36 Week study of the efficacy and safety of extended-release niacin/laropiprant in patients with type 2 diabetes. The registry record lists an enrollment of 796 and a completed status. The recorded start was 2007-07 and primary completion was 2008-08.
The intervention descriptions provide some detail about the regimens. In the treatment group, participants received one tablet of ER niacin/laropiprant (1g) with one tablet of the run-in statin dose, advancing to ER niacin/laropiprant (2g) at Week 4 for the remainder of the study. In the placebo group, participants continued a stable lipid-modifying regimen and added placebo ER niacin/laropiprant in week 4. The registry record does not specify the placebo formulation or describe the run-in procedure beyond the dose reference.
The primary outcome was percent change in low-density lipoprotein cholesterol from baseline at Week 12, with a least-squares mean and a 95% confidence interval reported for each arm. The primary endpoint population is identified as the Full Analysis Set. The posted arm summaries list 432 participants for ER niacin/laropiprant and 336 for placebo. These are the endpoint analysis counts; they should not be read as the safety denominators or as a complete account of participant flow.
The registry lists two secondary outcomes: week 12 percent change from baseline in high-density lipoprotein cholesterol and triglycerides. Results for these outcomes are not reported in the registry record. More detail on recruitment, inclusion criteria, randomization procedures, treatment adherence, and participant disposition is 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.
Before assignment: Patients with Type 2 Diabetes who were not at protocol specified low-density lipoprotein cholesterol goal of \<115 milligrams/deciliter at screening, had a 4-week run-in period of lipid modifying therapy. In order to advance to randomization, patients had to meet the low-density lipoprotein cholesterol goal.
Overall Study
| Stage | Extended Release Niacin/Laropiprant | Placebo |
|---|---|---|
| STARTED | 454 | 342 |
| COMPLETED | 298 | 277 |
| NOT COMPLETED | 156 | 65 |
Reasons for not completing this period:
| Reason | Extended Release Niacin/Laropiprant | Placebo |
|---|---|---|
| Adverse Event | 102 | 31 |
| Death | 0 | 1 |
| Lost to Follow-up | 5 | 1 |
| Physician Decision | 3 | 3 |
| Protocol Violation | 11 | 2 |
| Withdrawal by Subject | 32 | 27 |
| Study Terminated by Sponsor | 3 | 0 |
Analysis population for the primary outcome, as defined in the registry: Full Analysis Set
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 | Extended Release Niacin/Laropiprant | Placebo | Total |
|---|---|---|---|---|
| Participants analysed | 454 | 342 | 796 | |
| Age, Continuous | years | 62.0 (SD 9.3) | 62.0 (SD 9.4) | 62.0 (SD 9.3) |
| Sex: Female, Male: Female | Participants | 188 | 126 | 314 |
| Sex: Female, Male: Male | Participants | 266 | 216 | 482 |
| Fasting Plasma Glucose | milligrams/deciliter | 132.0 (SD 33.9) | 133.6 (SD 32.4) | 132.7 (SD 33.3) |
| High-density lipoprotein cholesterol | milligrams/deciliter (mg/dl) | 49.93 (SD 13.49) | 50.26 (SD 13.23) | 50.07 (SD 13.37) |
| Low-density lipoprotein cholesterol | milligrams/deciliter (mg/dl) | 87.19 (SD 20.54) | 85.22 (SD 18.00) | 86.34 (SD 19.50) |
| Triglycerides | milligrams/deciliter (mg/dl) | 126.00 (32.00 to 628.00) | 129.00 (39.00 to 509.00) | 127.00 (32.00 to 628.00) |
6. Primary Endpoint
The registry lists the primary outcome as Percent Change at Week (Wk) 12 Compared to Baseline (Bl) in Low-density Lipoprotein Cholesterol in Patients With Type 2 Diabetes When Compared to Placebo, measured over Baseline and 12 Weeks.
| Element | Registry entry |
|---|---|
| Result type | Least Squares Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | Percent change at Wk 12 compared to Bl |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is percent change in low-density lipoprotein cholesterol from baseline at Week 12. It is a continuous measure: it describes the relative movement in LDL cholesterol over the interval rather than an event such as hospitalization. The registry identifies the reported statistic as a least-squares mean and gives a 95% confidence interval for each treatment group.
LDL cholesterol is the lipid measure named in the primary objective. Comparing its change between randomized groups allows the analysis to describe how the endpoint differed under the two assigned regimens during the study period. The endpoint description specifically frames the assessment as reduction in LDL cholesterol among patients with type 2 diabetes compared with placebo. The registry also lists HDL cholesterol and triglycerides as secondary lipid outcomes at Week 12, but their numerical results are not reported in the registry record.
General statistical context: a continuous endpoint retains information about the amount and direction of change, rather than reducing the outcome to whether a participant crossed a threshold. Percent change puts the movement relative to baseline on a common scale. Interpretation still depends on how baseline and follow-up values were measured and handled; those measurement and missing-data details are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
For the primary endpoint, the posted least-squares mean percent change from baseline at Week 12 was -15.8 for ER niacin/laropiprant, with a 95% confidence interval from -18.4 to -13.2. For placebo, the corresponding mean was 2.1, with a 95% confidence interval from 0.3 to 4.6. The endpoint counts were 432 and 336, respectively. These arm-level summaries describe the direction and precision of the estimated change in each group.
The registry reports a between-group mean difference in final values of -17.9, with a 95% confidence interval from -21.4 to -14.4 and p <0.001. The estimate is negative in the comparison as reported, and its confidence interval does not include zero. The p-value is evidence against the null hypothesis used for that reported comparison under its analysis method; it is not a measure of the probability that the null hypothesis is true, nor a measure of the size or importance of an effect.
The registry identifies the comparison method as Wilcoxon (Mann-Whitney), while naming the reported parameter as mean difference (final values). The primary endpoint description, by contrast, specifies least-squares means of percent change. These labels should be kept distinct: the arm summaries describe the stated percent-change endpoint, and the posted analysis reports a comparison using the method and parameter labels in the registry. The record does not provide enough methodological detail to reconcile those labels or to infer an adjusted analysis beyond what is explicitly reported.
The intervals communicate uncertainty around the reported estimates. General statistical context: a confidence interval gives a range of values compatible with the data and the method’s assumptions; it does not guarantee that the true value lies in the interval. The arm-specific intervals and the between-group interval answer different questions, so they should not be treated as interchangeable. In particular, a difference between the arm-level point estimates is not a substitute for the registry’s reported comparison.
The result applies to the stated endpoint, time point, analysis population, and treatment regimens. It does not by itself describe later lipid measurements, the two secondary outcomes, or clinical events. Numerical results for HDL cholesterol and triglycerides are not reported in the registry record. The posted primary result also does not establish what would happen in populations or treatment settings not described in the record.
9. Statistical Methods Explained
The registry presents the primary endpoint as a continuous outcome: percent change in LDL cholesterol from baseline at Week 12. For each group, it reports a least-squares mean and a 95% confidence interval. It also reports one between-group analysis, identified as Wilcoxon (Mann-Whitney), with a parameter described as mean difference (final values), a 95% confidence interval, and a p-value. The record does not explain in detail how these analysis labels relate to one another.
What does a least-squares mean describe?
General statistical context: a least-squares mean is a model-based estimate of a group mean. Depending on the specified model, it can account for other variables or design features, unlike a simple arithmetic mean. The registry record does not report the model specification, covariates, or adjustment details for this endpoint. It is therefore appropriate to describe the posted values as least-squares means without inferring which factors, if any, were included in the model.
How should the confidence intervals be read?
The arm-level intervals quantify uncertainty around the estimated percent change for each group, while the interval for the between-group estimate quantifies uncertainty around that comparison. General statistical context: a confidence interval is constructed by a statistical procedure that, over repeated applications under its assumptions, has a stated coverage property. It is not a range containing every participant’s outcome and does not show how variable individual responses were. The registry lists the interval level as 95%. It does not provide a separate measure of participant-level spread for this endpoint.
The interval for the reported between-group estimate is from -21.4 to -14.4. Since zero is not within that interval, its values point to a difference under the reported analysis. This does not establish clinical importance or explain the analysis model. General statistical context: interval width reflects both the estimate’s uncertainty and the method used to construct the interval; interpreting it requires attention to the endpoint definition, analysis population, and assumptions.
What does the Wilcoxon (Mann-Whitney) label imply?
General statistical context: the Wilcoxon rank-sum test, also called the Mann-Whitney test, compares the distributions of observations between groups using ranks. It does not automatically test a difference in arithmetic means. Under additional assumptions, rank-based results may be interpreted in terms of a location shift, but that interpretation depends on the shape and spread of the distributions. The registry calls the method Wilcoxon (Mann-Whitney) but labels the parameter as mean difference (final values). It does not report the test statistic, the exact calculation of the interval, or assumptions that would clarify this pairing. The reported result should therefore be presented using the registry’s own labels rather than recast as a different estimand.
Why can over-dispersion matter?
General statistical context: over-dispersion occurs when the variability in data is greater than a model expects. If a method assumes less variability than the data contain, standard errors and confidence intervals can be too small, and tests can appear more decisive than warranted. This issue is especially relevant to count outcomes and some models for event data. The primary endpoint is continuous, and the registry does not report a model diagnostic or a dispersion assessment. The relevance of over-dispersion to the reported analysis is therefore not reported in the registry record.
What can the planning illustrations tell a reader?
The planning illustrations use the observed effect as a reference and assume a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. They consider detecting a stated fraction of the observed effect. Such illustrations are planning scenarios, not evidence about the trial’s actual design decisions, and not observed power. The registry record does not report that these assumptions were used to plan the trial, nor does it report the trial’s own sample-size justification. Any illustrated number of participants per arm should be read as a planning quantity under those assumptions, not as a feature of the enrolled or analyzed groups.
For non-time-to-event outcomes, the planning convention is participants per arm. These calculations do not resolve uncertainty about missing observations, endpoint distributions, model specification, or the analysis population. The registry record does not report interim analyses, a statistical analysis plan, or additional detail about how the primary endpoint analysis was conducted.
10. Analyses Reported by the Sponsor
| Method | Estimate | 95% CI | P-value |
|---|---|---|---|
| Wilcoxon (Mann-Whitney) | Mean Difference (Final Values) -17.9 | -21.4 to -14.4 | < 0.001 |
The registry’s own reported comparison is the principal inferential result available for the primary endpoint: a Wilcoxon (Mann-Whitney) analysis, with the parameter labelled mean difference (final values), an estimate of -17.9, a 95% confidence interval from -21.4 to -14.4, and p <0.001. The arm summaries separately report least-squares mean percent change from baseline at Week 12.
A separate simple, unadjusted re-calculation from the posted summary statistics is not estimable for this continuous two-arm comparison in the registry output. Accordingly, there is no recalculated estimate to compare numerically with the registry analysis. The reported arm-level means and intervals should not be used to construct a replacement comparison or treated as if they were the sponsor’s analysis. The registry record does not provide further details about the relationship between the analysis method and parameter labels, or the underlying calculation of the reported interval.
11. Multiplicity, Missing Data and Analysis Populations
The registry identifies one primary endpoint and two secondary outcomes: percent change from baseline at Week 12 in HDL cholesterol and triglycerides. It reports three outcome measures and three analyses in the record, but numerical results for the two secondary outcomes are not reported in the registry record. No multiplicity adjustment, hierarchy among outcomes, or family of hypotheses is described in the registry record.
General statistical context: when several outcomes or comparisons are tested, the chance of at least one apparently unusual result can increase if each is assessed separately at the same threshold. Methods for addressing this include adjusting significance thresholds or specifying an ordered testing strategy in advance. Without the statistical plan, it is not possible to determine whether such an approach was intended or used. The p-value for the primary comparison should therefore be read as the result of the comparison reported, not as evidence that the full set of outcomes was handled in a particular way.
The primary endpoint population is named as the Full Analysis Set. The record does not define membership in that set, describe exclusions, or report participant flow by reason. It also does not explain how missing baseline or Week 12 measurements were handled, whether values were imputed, or whether sensitivity analyses were performed. These details are not reported in the registry record. Missing-data handling can affect which observations contribute to an estimate and how uncertainty is assessed, so the reported result cannot be used to infer a specific missing-data procedure.
The endpoint counts are 432 for ER niacin/laropiprant and 336 for placebo. The safety at-risk counts are different, and the record does not explain the relationship between the analysis populations. These should be treated as endpoint and safety denominators as reported, not combined into a single participant count. No interim-analysis plan or stopping rule is reported in the registry record.
12. 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 |
|---|---|---|---|
| Extended Release Niacin/Laropiprant | 26 | 449 | 5.8% |
| Placebo | 24 | 340 | 7.1% |
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 |
|---|---|
| Extended Release Niacin/Laropiprant | 251 of 449 |
| Placebo | 113 of 340 |
Most frequent serious adverse event terms
| Event term | Organ system | Extended Release Niacin/Laropiprant | Placebo |
|---|---|---|---|
| Coronary artery disease | Cardiac disorders | 1 of 449 | 2 of 340 |
| Non-cardiac chest pain | General disorders | 1 of 449 | 2 of 340 |
| Erysipelas | Infections and infestations | 2 of 449 | 1 of 340 |
| Angina unstable | Cardiac disorders | 0 of 449 | 2 of 340 |
| Myocardial infarction | Cardiac disorders | 2 of 449 | 0 of 340 |
| Prostate cancer | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 1 of 449 | 1 of 340 |
| Renal failure acute | Renal and urinary disorders | 2 of 449 | 0 of 340 |
| Anaemia | Blood and lymphatic system disorders | 0 of 449 | 1 of 340 |
| Angina pectoris | Cardiac disorders | 0 of 449 | 1 of 340 |
| Aortic valve stenosis | Cardiac disorders | 1 of 449 | 0 of 340 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Extended Release Niacin/Laropiprant | Placebo |
|---|---|---|---|
| Flushing | Vascular disorders | 79 of 449 | 16 of 340 |
| Pruritus | Skin and subcutaneous tissue disorders | 71 of 449 | 9 of 340 |
| Blood glucose increased | Investigations | 52 of 449 | 14 of 340 |
| Diarrhoea | Gastrointestinal disorders | 41 of 449 | 21 of 340 |
| Nasopharyngitis | Infections and infestations | 33 of 449 | 25 of 340 |
| Upper respiratory tract infection | Infections and infestations | 28 of 449 | 24 of 340 |
| Headache | Nervous system disorders | 20 of 449 | 18 of 340 |
| Nausea | Gastrointestinal disorders | 24 of 449 | 12 of 340 |
| Rash | Skin and subcutaneous tissue disorders | 26 of 449 | 5 of 340 |
Serious events with the highest arm-level rate: angina unstable (0.6%), coronary artery disease (0.6%), non-cardiac chest pain (0.6%), myocardial infarction (0.4%), erysipelas (0.4%).
The posted safety data list serious adverse events for 26 participants among 449 at risk in the ER niacin/laropiprant group and 24 among 340 at risk in the placebo group. Other adverse events are listed for 251 among 449 at risk in the treatment group and 113 among 340 at risk in the placebo group. These are descriptive counts with their stated denominators; the registry does not report a statistical comparison of these figures.
The listed serious-event terms and percentages are unstable angina, 0.6%; coronary artery disease, 0.6%; non-cardiac chest pain, 0.6%; myocardial infarction, 0.4%; erysipelas, 0.4%; and acute renal failure, 0.4%. The registry record does not give group-specific counts for each listed term in the information, so the percentages should not be assigned to a group without further detail. Death counts are not reported in the registry record.
General statistical context: adverse-event summaries are descriptive and do not, by themselves, establish that an event was caused by treatment. The registry record does not provide event definitions, severity grading beyond the serious-event category, exposure-adjusted rates, or a formal safety comparison. The counts also have different denominators from the primary endpoint summaries and should not be substituted for them.
13. What the Result Does, and Does Not, Mean
The primary result describes a difference between randomized groups in the reported Week 12 LDL cholesterol outcome. The arm-level least-squares mean percent changes were -15.8 for ER niacin/laropiprant and 2.1 for placebo. The registry’s reported between-group analysis gives a mean difference (final values) of -17.9, with a 95% confidence interval from -21.4 to -14.4 and p <0.001. These statistics indicate that the posted comparison is estimated with an interval that does not include zero under the reported method.
The result does not, on its own, establish the clinical importance of the measured difference. No threshold for a clinically meaningful change is reported in the registry record, and the endpoint is a lipid measurement rather than a patient-centered clinical event. The result also does not describe the HDL cholesterol or triglyceride outcomes: their numerical findings are not reported in the registry record.
The comparison concerns the regimens and study population described in this record, at the stated time point. The registry identifies patients with type 2 diabetes and a Full Analysis Set but does not give a detailed definition of that analysis population. The posted statistics do not establish effects beyond the study period or in other populations, nor do they show how missing measurements, adherence, or treatment changes may have influenced the estimates.
The safety information is likewise limited. It gives counts of participants with serious and other adverse events and lists selected serious-event terms, but does not report a formal between-group safety analysis or deaths. These figures should be read as recorded safety descriptions, not as proof of causation or as a complete account of comparative safety.
General statistical context: a small p-value is not a measure of clinical importance, and a confidence interval does not account for every uncertainty in study conduct or reporting. Interpretation depends on the endpoint, analysis method, population, missing-data approach, and the wider evidence. Several of those details are not reported in the registry record.
14. Why This Trial Matters Statistically
This trial illustrates why endpoint estimates and between-group analyses need to be read together but not conflated. The primary outcome is presented as least-squares mean percent change in LDL cholesterol at Week 12, while the reported comparison is labelled as a Wilcoxon (Mann-Whitney) analysis with a mean difference in final values. A reader can report both exactly as registered while recognizing that the record does not explain their methodological relationship.
It also shows the importance of keeping analysis populations and denominators distinct. The primary endpoint summaries use counts of 432 and 336, while the safety summaries use at-risk counts of 449 and 340. Without participant-flow details, these counts cannot be reconciled from the registry record. Treating them as interchangeable would obscure which observations contribute to each result.
The 95% confidence intervals add information beyond the point estimates by expressing uncertainty under the stated analysis. The reported between-group interval does not include zero, and the p-value is p <0.001. Neither statistic answers questions about clinical importance, the missing-data process, or the secondary outcomes. Those require information that is not reported in the registry record.
Finally, planning illustrations based on an observed effect can help readers understand the implications of a chosen effect size under explicit assumptions, but they are not a record of the original design rationale. Distinguishing such scenarios from the trial’s own sample-size planning helps prevent a retrospective calculation from being mistaken for a prespecified design feature.
15. 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 registry record gives only limited detail about trial conduct and statistical analysis. It identifies randomization, double masking, parallel groups, and placebo control, but does not describe the randomization sequence, allocation concealment, masking procedures, or protocol deviations. The sample-size justification, statistical analysis plan, interim analyses, and stopping rules are not reported in the registry record.
The primary endpoint is described as a least-squares mean percent change, while the reported comparison is identified as Wilcoxon (Mann-Whitney) and labelled mean difference (final values). The record does not provide the model specification, test statistic, interval calculation, or enough detail to reconcile those labels. No separate unadjusted recalculation is estimable from the posted summary statistics for this continuous two-arm comparison.
The Full Analysis Set is named but not defined. Participant flow, reasons for exclusion, adherence, exposure duration by group, and handling of missing Week 12 data are not reported in the registry record. The endpoint counts and safety at-risk counts differ, and the record does not explain that difference. The two secondary outcomes are listed without numerical results, and no multiplicity strategy is reported.
The safety information is limited to aggregate counts, selected serious-event terms and percentages, and at-risk denominators. Deaths are not reported in the registry record. Event definitions, group-specific counts for each listed term, exposure-adjusted rates, and formal comparative safety analyses are also not reported. These gaps limit interpretation of both the efficacy analysis and the safety descriptions.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: Extended Niacin/Laropiprant in Patients With Type 2 Diabetes (0524A-069) — NCT00485758.
- Registry record last updated 2015-10-12; status last verified 2015-10.
- Results first posted 2009-09-11.
- 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.
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19. Record Summary
NCT00485758 is a completed phase 3, randomized, double-blind, parallel-group, placebo-controlled study of extended-release niacin/laropiprant in patients with type 2 diabetes. The registry lists an enrollment of 796, a start of 2007-07, and primary completion in 2008-08. The official title describes a 36 Week study.
The primary endpoint was percent change from baseline in LDL cholesterol at Week 12. The posted least-squares mean changes were -15.8 for ER niacin/laropiprant and 2.1 for placebo. The reported between-group analysis gave a mean difference (final values) of -17.9, a 95% confidence interval from -21.4 to -14.4, and p <0.001. Two secondary lipid outcomes are listed, but their numerical results are not reported in the registry record.
Safety summaries list serious and other adverse-event counts by group. The record does not report deaths, a detailed missing-data method, or a multiplicity strategy.