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Severe Hypertriglyceridemia Phase 2, Phase 3 Continuous Endpoint NCT01242527

Epanova® for Lowering Very High Triglycerides: Complete Statistical Analysis

This randomized trial compared Epanova at three daily doses with olive oil placebo in participants with severe hypertriglyceridemia. The primary outcome was percent change in fasting serum triglycerides after 12 weeks, with registry-reported adjusted comparisons against placebo.

Trial start: 2011-01  ·  Enrollment: 399  ·  Sponsor: AstraZeneca
Scope of this record

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 Epanova® for Lowering Very High Triglycerides (NCT01242527), a randomized phase 2, phase 3 study. The primary outcome is Fasting Serum Triglycerides.

399
Enrollment
Phase 2, Phase 3
4
Arms
In the primary outcome
n/a
Effect
No re-analysis shown
n/a
95% CI
See limitations
FeatureRegistry value
ClinicalTrials.gov identifierNCT01242527
PhasePhase 2, Phase 3
ConditionSevere Hypertriglyceridemia
AllocationRandomized
Design modelParallel
MaskingQuadruple
Enrollment399
Arms in the primary outcome4
Lead sponsorAstraZeneca
Results postedYes

2. Clinical Question

Population

Participants with severe hypertriglyceridemia were enrolled. The registry describes the primary analysis population as the Intent-to-Treat (ITT) Population, comprising all randomized subjects, with a modified ITT Population used for randomized subjects who terminated before treatment or had no post-treatment efficacy assessments. The registry does not give further eligibility details in this record.

Intervention

The active interventions were Epanova at daily doses of 2 g, 3 g, and 4 g. The primary outcome was assessed at 12 weeks. The registry lists the drug interventions as omefas and labels the treatment arms Epanova.

Comparator

The comparator was olive oil placebo. The record describes the study objective as comparing Epanova with placebo for lowering serum triglycerides. The registry does not report further details about the placebo regimen in this record.

Primary question

The primary question was whether the mean percent change from baseline in fasting serum triglycerides at the end of treatment differed between placebo and each Epanova dose group. The registry reports placebo-adjusted comparisons for all three active doses, with 95% confidence intervals and p-values. These are comparisons of a laboratory outcome over the trial's 12-week treatment period, not a direct assessment of clinical events or long-term outcomes.

3. Trial Design

This completed trial was randomized, quadruple-masked, and used a parallel-group design. Its listed phases were Phase 2 and Phase 3. The registry reports enrollment of 399 participants and identifies AstraZeneca as the sponsor. The study began in 2011-01, with primary completion in 2012-03.

Participants were assigned to olive oil placebo or one of three Epanova dose groups: 2 g, 3 g, or 4 g. The primary endpoint was fasting serum triglycerides, expressed as percent change from baseline, with assessment at 12 weeks. The record describes the primary objective as determining Epanova's efficacy compared with placebo in lowering serum triglycerides among subjects with severe hypertriglyceridemia.

The posted primary outcome summaries include 98 participants in the placebo arm, 99 in the Epanova 2 g arm, 97 in the Epanova 3 g arm, and 99 in the Epanova 4 g arm. These are the group counts reported with the outcome measure. They should not be confused with the registry's overall enrollment figure, which describes enrollment for the trial as a whole.

The registry defines the ITT Population as all randomized subjects. It also states that a modified ITT Population was implemented for randomized subjects who terminated before treatment or had no post-treatment efficacy assessments. Further detail on how that population was constructed or how many subjects it included is not reported in the registry record. Allocation concealment, the identities of the masked parties, and details of treatment delivery 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.

Before assignment: Subjects who needed to washout omega-3 drugs/supplements or adjust or add a permitted statin, CAI or combination had an 8-week screening. All other subjects, including those on a stable statin, CAI or statin-CAI, or who needed to washout of bile acid sequestrants, fibrates, niacin and other lipid altering supplements had a 4-week screening period.

Overall Study

StageOlive Oil (Placebo Control)Epanova 2 gEpanova 3 gEpanova 4 g
STARTED9910010199
COMPLETED94938790
NOT COMPLETED57149

Analysis population for the primary outcome, as defined in the registry: The Intent-to-Treat (ITT) Population was comprised of all subjects who were randomized. In the event that randomized subjects terminated before treatment or had no post-treatment efficacy assessments, a modified ITT Population was implemented.

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.

CharacteristicUnitOlive Oil (Placebo)Epanova 2 gEpanova 3 gEpanova 4 gTotal
Participants analysed9910010199399
Age, ContinuousYears50.8 (SD 10.59)51.1 (SD 9.79)51.2 (SD 8.75)52.9 (SD 10.92)51.5 (SD 10.04)
Sex: Female, Male: FemaleParticipants2220222892
Sex: Female, Male: MaleParticipants77807971307
Ethnicity (NIH/OMB): Hispanic or LatinoParticipants684725
Ethnicity (NIH/OMB): Not Hispanic or LatinoParticipants93929792374
Ethnicity (NIH/OMB): Unknown or Not ReportedParticipants00000

6. Primary Endpoint

The registry lists the primary outcome as Fasting Serum Triglycerides, measured over 12 weeks.

ElementRegistry entry
Result typeLeast Squares Mean
Measure of spread95% Confidence Interval
UnitPercent change from baseline
Endpoint classificationContinuous Endpoint

The primary endpoint was fasting serum triglycerides, summarized as percent change from baseline to the end of treatment at 12 weeks. It is a continuous measure: each participant's outcome can take a range of numeric values rather than being limited to a yes-or-no event. The registry reports least-squares means and 95% confidence intervals for each treatment arm.

Percent change expresses how the measured triglyceride value at follow-up relates to that participant's baseline value. A negative value indicates a decrease from baseline; a value closer to zero indicates a smaller decrease or a change in the opposite direction. This description concerns the scale of the outcome and does not, by itself, establish the clinical importance of a change.

As a general statistical point, a continuous laboratory endpoint can retain information about the size of changes across participants rather than reducing outcomes to whether a threshold was crossed. That can make it useful for comparing average changes between randomized groups. The registry's primary question concerns the mean percent change for placebo versus each of the three Epanova doses. It does not report a primary clinical-event endpoint in this record.

7. Why No Re-analysis Is Shown

Reported as posted, not recalculated. Values missing or not estimable for a two-arm comparison (continuous endpoint). A result is recalculated only when the posted data support a clean two-arm comparison, so no result is shown beyond what the sponsor posted.

8. Statistical Interpretation

Clinical Biostats interpretation

The registry reports least-squares mean percent changes of -4.26 for olive oil placebo, -25.94 for Epanova 2 g, -25.46 for Epanova 3 g, and -30.86 for Epanova 4 g. The corresponding 95% confidence intervals are -13.07 to 5.44, -32.84 to -18.33, -32.44 to -17.75, and -37.32 to -23.74, respectively. These are group-level estimates of change from baseline, not individual participant results.

The separate placebo-adjusted estimates reported by the registry are -21.68 for Epanova 2 g, -21.19 for Epanova 3 g, and -26.60 for Epanova 4 g. Their 95% confidence intervals are -40.70 to -2.89, -40.32 to -2.29, and -45.12 to -8.38, respectively. The associated reported p-values are 0.005, 0.007, and <0.001. Under the stated direction of the comparisons, each estimate is negative, indicating a lower modeled percent change for the active group relative to placebo.

Each adjusted confidence interval lies below zero, and each reported p-value is below 0.05. In the framework of the reported analyses, these results are evidence against a zero placebo-adjusted difference for each comparison. A p-value is not the probability that the null hypothesis is true, nor does it measure the size or clinical importance of the difference. The confidence intervals convey uncertainty in the adjusted estimates; their width also shows that the exact size of each difference is not precisely determined.

The arm-level estimates and the placebo-adjusted estimates answer related but distinct questions. The arm summaries describe estimated percent change within each group. The adjusted contrasts compare each active dose with placebo using the registry's stated analysis. The adjusted contrast should not be recreated by subtracting the arm-level estimates: the analysis was an ANCOVA on ranked data, and the record does not give enough model detail to reproduce that analysis from the arm summaries alone.

The estimates are limited to the 12-week endpoint and the population used for the analysis. They do not describe longer-term outcomes, effects on clinical events, or results in populations not represented in the trial. The registry lists three pairwise dose-versus-placebo analyses. Whether and how the reported p-values account for multiple comparisons is not reported in the registry record, so the p-values should be read as reported rather than as evidence of a stated multiplicity-adjusted procedure.

9. Statistical Methods Explained

What does ANCOVA on ranked data mean?

The registry identifies the comparison method as an ANCOVA p-value on ranked data. ANCOVA is a general method for comparing groups while accounting for selected covariates. The covariates used in these analyses are not reported in the registry record. The phrase “on ranked data” indicates that the outcome values were converted to their relative ranks for at least part of the analysis rather than analyzed only on their original numeric scale. Ranking can be useful when the assumptions of a standard continuous-outcome model are in doubt, but the registry does not state why this approach was selected for this trial.

As a general explanation, an ANCOVA analysis commonly produces an adjusted comparison between groups, while taking account of covariates included in the model. The term “adjusted” does not identify which covariates were used or establish that every possible source of imbalance was addressed. Those modeling details are not reported in the registry record. The reported estimates are labeled placebo-adjusted percent changes, while the method description specifically identifies the p-value calculation as ANCOVA on ranked data. The exact procedure used to obtain each estimate and confidence interval is not described in greater detail.

What does a least-squares mean represent?

A least-squares mean is a model-based group summary, rather than necessarily the simple arithmetic average of the observed values. In general, it represents an estimated group mean under the statistical model. The registry reports this parameter for the arm-level percent changes, but does not provide the covariate specification or other model details needed to interpret exactly how the estimates were adjusted.

The reported arm-level estimates are -4.26 for placebo and -25.94, -25.46, and -30.86 for the three Epanova doses. Those values are accompanied by 95% confidence intervals. They summarize estimated change in each group; the separate placebo-adjusted estimates are the registry's direct comparisons between each dose and placebo. The analysis method and available information do not justify treating the arm summaries as a substitute for those direct comparisons.

How should the confidence intervals be read?

A confidence interval describes uncertainty around an estimate under the statistical procedure used to construct it. In general, a 95% confidence interval is produced by a method designed to capture the underlying target value in 95% of repeated samples under the method's assumptions. It is not a statement that there is a 95% probability that this particular interval contains the true value.

For the adjusted comparisons, the intervals range from -40.70 to -2.89 for Epanova 2 g, from -40.32 to -2.29 for Epanova 3 g, and from -45.12 to -8.38 for Epanova 4 g. All three intervals are below zero. Their widths indicate that the data are compatible with a range of negative adjusted differences, not just the point estimates. The interval bounds are not a guarantee that all plausible values have equal support, and they do not describe variation among individual participants.

What does a p-value tell the reader?

A p-value evaluates how unusual the observed data, or data more extreme, would be under a specified null hypothesis and statistical model. It is not the probability that a result occurred by chance, and it does not tell the reader the probability that a treatment effect exists. The reported p-values are 0.005, 0.007, and <0.001 for the three dose comparisons. They are the values attached to the registry's reported ranked-data ANCOVA analyses.

As a general statistical point, interpretation of multiple p-values depends in part on whether the analysis plan accounts for the number of comparisons. The registry lists three dose-versus-placebo analyses but does not report a multiplicity procedure. No adjustment should be assumed from the available record.

What can be inferred from the planning illustrations?

The sample-size planning assumptions describe illustrations based on the observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They are not the trial's own design justification, and the registry record does not report the trial's sample-size justification. Such calculations are planning illustrations: they do not measure the power actually achieved in a completed trial. The assumptions also specify that the effect to detect is a stated fraction of the observed effect. The specific planning results are not interpreted as observed outcomes.

Sample-size calculations depend on assumptions about the target effect, variability, allocation, and statistical method. In general, changing those assumptions changes the calculated number of participants needed. The planning assumptions in this record should therefore be read as conditional scenarios, not as evidence about the trial's design process or the probability that the trial detected an effect.

The registry reports 95% confidence intervals and p-values but does not give the full analysis plan, the covariates, the method for handling missing endpoint values, or details of any interim analyses. These omissions limit independent reproduction and assessment of the statistical model.

10. Analyses Reported by the Sponsor

MethodEstimate95% CIP-value
ANCOVA p-value on ranked dataPlacebo adjusted % change from baseline -21.68-40.70 to -2.890.005
ANCOVA p-value on ranked dataPlacebo adjusted % change from baseline -21.19-40.32 to -2.290.007
ANCOVA p-value on ranked dataPlacebo adjusted % change from baseline -26.60-45.12 to -8.38< 0.001

The registry reports three placebo-adjusted analyses using ANCOVA p-values on ranked data. The estimates are -21.68 for Epanova 2 g, -21.19 for Epanova 3 g, and -26.60 for Epanova 4 g, with p-values of 0.005, 0.007, and <0.001, respectively. These are the reported adjusted comparisons and should be distinguished from simple unadjusted calculations based on arm-level summary statistics.

An unadjusted calculation from posted summaries would not reproduce an analysis that uses ranked data and model adjustment. The registry does not report enough detail about the covariates or model implementation to independently reconstruct the adjusted analyses. The record does not flag a discrepancy between the posted analyses and recalculation. The sponsor's own analysis takes precedence if a discrepancy is flagged; no such discrepancy is identified in this record.

The adjusted results are therefore best read as the registry-reported analysis, while the arm-level least-squares means remain separate estimates of change within each group. Neither the reported p-values nor the adjusted contrasts state how multiplicity was handled; that procedure is not reported in the registry record.

11. Multiplicity, Missing Data and Analysis Populations

The primary outcome description defines three comparisons: placebo versus Epanova 2 g, placebo versus Epanova 3 g, and placebo versus Epanova 4 g. The registry reports an estimate, 95% confidence interval, and p-value for each. It also lists one outcome measure and no posted secondary outcome measures.

When several comparisons are made, the chance of at least one false positive can be affected by whether the analysis uses a multiplicity adjustment. This is a general statistical consideration, not a statement about the procedure used in this trial. The registry record does not report whether the three primary comparisons were adjusted for multiplicity, whether one comparison was designated as primary among them, or what decision rule was specified in advance. The reported p-values should therefore be described as posted, without labeling them adjusted or unadjusted for multiplicity.

The primary population description says that the ITT Population included all randomized subjects. It further says that a modified ITT Population was implemented if randomized subjects terminated before treatment or had no post-treatment efficacy assessments. The record does not state the number included in that modified population, how missing measurements were handled, or whether any imputation or other missing-data procedure was used.

The outcome arm counts are 98 for placebo, 99 for Epanova 2 g, 97 for Epanova 3 g, and 99 for Epanova 4 g. The registry's overall enrollment is 399. The record does not explain the relationship between these outcome counts and the modified ITT definition, or give a participant flow accounting for exclusions from the endpoint analysis. The exact analysis population used for each reported comparison is not described beyond the primary population definition.

Interim analyses, stopping rules, and a prespecified statistical analysis plan are not reported in the registry record. Their absence from this record does not establish whether they were or were not used; it means the posted information does not allow those features to be assessed.

12. Safety Results

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

ArmParticipants with serious adverse eventsParticipants at riskPercentage
Olive Oil (Placebo)2992.0%
Epanova 2 g11001.0%
Epanova 3 g41014.0%
Epanova 4 g0990.0%
Participants with at least one serious adverse event
Serious adverse events by armOlive Oil (Placebo)2.0%Epanova 2 g1.0%Epanova 3 g4.0%Epanova 4 g0.0%% of participants with at least one serious adverse event

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

ArmParticipants affected of at risk
Olive Oil (Placebo)5 of 99
Epanova 2 g23 of 100
Epanova 3 g18 of 101
Epanova 4 g16 of 99

Most frequent serious adverse event terms

Event termOrgan systemOlive Oil (Placebo)Epanova 2 gEpanova 3 gEpanova 4 g
Angina pectorisCardiac disorders0 of 991 of 1001 of 1010 of 99
MyocarditisCardiac disorders1 of 990 of 1000 of 1010 of 99
Abdominal painGastrointestinal disorders1 of 990 of 1000 of 1010 of 99
Coronary artery diseaseCardiac disorders0 of 990 of 1001 of 1010 of 99
Pulmonary embolismRespiratory, thoracic and mediastinal disorders0 of 990 of 1001 of 1010 of 99
Implantable defibrillator insertionCardiac disorders0 of 990 of 1001 of 1010 of 99

Most frequent non-serious adverse event terms

Event termOrgan systemOlive Oil (Placebo)Epanova 2 gEpanova 3 gEpanova 4 g
DiarrhoeaGastrointestinal disorders2 of 9910 of 1006 of 10110 of 99
NauseaGastrointestinal disorders1 of 996 of 1009 of 1015 of 99
NasopharyngitisInfections and infestations2 of 997 of 1003 of 1011 of 99

Serious events with the highest arm-level rate: myocarditis (1.0%), abdominal pain (1.0%), angina pectoris (1.0%), coronary artery disease (1.0%), pulmonary embolism (1.0%).

Do not overextend the safety comparison. Serious-adverse-event counts are safety observations, not efficacy outcomes, and should not be combined with the primary result into a single benefit-risk number.

The adverse-event record reports serious adverse events for 2 participants in the olive oil placebo group, 1 in the Epanova 2 g group, 4 in the Epanova 3 g group, and 0 in the Epanova 4 g group. The corresponding numbers at risk are 99, 100, 101, and 99. These are the registry's reported counts; the record does not provide a deaths value for these groups.

The listed serious-event terms are myocarditis, abdominal pain, angina pectoris, coronary artery disease, pulmonary embolism, and implantable defibrillator insertion. Each is listed as 1.0%. The record does not map these terms to particular treatment arms, and it does not state whether an individual could contribute to more than one event term. The terms therefore should not be interpreted as a complete arm-by-arm breakdown.

Other adverse events are reported for 5 participants in the placebo group, 23 in the Epanova 2 g group, 18 in the Epanova 3 g group, and 16 in the Epanova 4 g group; the numbers at risk are 99, 100, 101, and 99. These counts alone do not establish that an event was caused by treatment. The registry record does not provide further detail about event definitions, duration, severity grading, or the method used to collect events.

Safety counts are descriptive. Differences in counts between groups should not be treated as proof of a causal relationship, particularly without additional information about event ascertainment and analysis. The record's lack of a deaths value means deaths are not reported in the registry record.

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

The posted results describe changes in fasting serum triglycerides over 12 weeks among randomized participants with severe hypertriglyceridemia. The registry reports negative least-squares mean percent changes in all four groups, with a smaller estimated decrease in the olive oil placebo group than in the active-dose groups. Its separate adjusted comparisons are also negative, and their reported 95% confidence intervals lie below zero. The associated p-values are 0.005, 0.007, and <0.001.

These findings concern the measured laboratory endpoint and the statistical comparisons reported in the registry. They do not, on their own, establish the importance of the observed changes for symptoms, cardiovascular outcomes, or other clinical endpoints. Such outcomes are not reported as primary results in this record. The estimates also do not establish what happens beyond the 12-week timeframe.

Statistical evidence against a zero adjusted difference does not mean that the exact point estimate is known, that every participant had a similar response, or that any particular individual will have a specified outcome. Group means conceal variation among participants, and the registry's reported confidence intervals describe uncertainty in estimated group quantities rather than individual ranges.

The record does not report whether p-values were adjusted for the three dose comparisons, the full model specification, or the procedure for handling missing endpoint values. Those limits matter when judging how robustly the results can be interpreted or reproduced. The registry also does not report long-term follow-up or secondary outcome measures.

The trial results should therefore be read as evidence about modeled average percent change in a specific endpoint under the reported analysis. They do not establish a broader clinical benefit, long-term safety profile, or outcome in populations outside the trial. The posted registry information supports interpretation of the stated comparisons, but not conclusions that require unreported endpoints or methods.

14. Why This Trial Matters Statistically

This trial illustrates how a randomized parallel-group design can compare several doses with a common placebo group using a continuous endpoint. The primary measure, percent change in fasting serum triglycerides, preserves information about the magnitude and direction of change. The registry reports both arm-level estimates and dose-versus-placebo adjusted comparisons, which answer related but different statistical questions.

It also demonstrates why analysis details matter. The reported method is ANCOVA on ranked data, while the endpoint is expressed on its original percent-change scale. Without the covariates and model specification, a reader cannot reconstruct the adjusted estimates solely from the arm summaries. The registry's method description is informative, but it does not document the entire analysis procedure.

The record presents three active-dose comparisons, making multiplicity an important reporting consideration. Because the registry does not state whether a correction or other decision rule was used, the reported p-values should not be assumed to have a particular multiplicity interpretation. This is an example of why analysis-plan details are necessary to understand a set of related tests.

The population definition also matters: the record describes an ITT Population and a modified ITT condition for participants without treatment or post-treatment efficacy assessment, but does not explain the handling of missing data in detail. Clear reporting of analysis populations and missing-data procedures helps readers assess which participants inform the estimates.

Finally, this record distinguishes a short-term laboratory outcome from broader clinical outcomes. Statistical analysis can characterize the size and uncertainty of changes in the measured endpoint, but it cannot replace outcomes that were not reported. The trial is therefore useful for examining endpoint summaries, model-based contrasts, confidence intervals, p-values, and gaps in registry reporting.

15. Limitations

The registry does not report the full protocol or statistical analysis plan. In particular, the covariates used for the ranked-data ANCOVA, the method for constructing the adjusted confidence intervals, and the exact implementation of the model are not reported in the registry record. This restricts independent reproduction of the adjusted analyses.

The record does not report whether the three dose comparisons were adjusted for multiplicity. It also does not identify a prespecified hierarchy or decision rule across those comparisons. The p-values and confidence intervals can be described as posted, but their relation to any family-wise testing procedure cannot be established from this record.

The population description allows for a modified ITT Population in specified circumstances, but the record does not give the number of participants in that population, a participant flow for the endpoint, or the way missing outcome data were handled. The outcome counts by arm are reported, but the record does not explain why they differ from one another or how they correspond to the stated population rule.

The primary endpoint is measured at 12 weeks. Longer-term results and clinical-event outcomes are not reported in this record, and no secondary outcome measures are posted. The reported endpoint therefore cannot answer questions about effects beyond the stated timeframe or outcomes other than fasting serum triglycerides.

Safety reporting is also limited in the registry record. Serious-event counts are listed by group, and several serious-event terms are listed at 1.0%, but the terms are not allocated to treatment arms. Deaths are not reported in the registry record. Further details about event definitions, collection, severity, and attribution are not reported in the registry record.

The registry describes the trial as completed and gives enrollment and timing information, but does not report interim analyses, stopping rules, or the trial's sample-size justification. The planning assumptions associated with sample-size illustrations are not a substitute for a documented design rationale.

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19. Record Summary

NCT01242527, titled “Epanova® for Lowering Very High Triglycerides,” is a completed randomized, quadruple-masked, parallel-group study listed as Phase 2 and Phase 3. AstraZeneca is identified as the sponsor. The registry reports enrollment of 399 participants, a start in 2011-01, and primary completion in 2012-03.

Participants with severe hypertriglyceridemia were assigned to olive oil placebo or Epanova 2 g, 3 g, or 4 g. The primary outcome was fasting serum triglycerides, measured as percent change from baseline at 12 weeks. The registry reports least-squares means with 95% confidence intervals and three placebo-adjusted analyses using ANCOVA p-values on ranked data.

The posted adjusted estimates are negative for all three dose comparisons, with reported p-values of 0.005, 0.007, and <0.001. The record does not report the multiplicity procedure, full model specification, or detailed handling of missing outcome data. It lists one outcome measure and no posted secondary outcomes. Serious adverse-event counts are reported by group, while deaths and arm-specific serious-event terms are not reported in the registry record.

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