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Persistent Atrial Fibrillation Phase 2 Time-to-Event Analysis NCT01534962

Ranolazine in Atrial Fibrillation Following An ELectricaL CardiOversion: Complete Statistical Analysis

This analysis examines a randomized Phase II trial of three ranolazine doses versus placebo after electrical cardioversion for persistent atrial fibrillation. The primary outcome was time to first documented recurrence, with additional recurrence outcomes and safety counts recorded.

Trial start: 2012-01  ·  Enrollment: 241  ·  Sponsor: Menarini Group
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 Ranolazine in Atrial Fibrillation Following An ELectricaL CardiOversion (NCT01534962), a randomized phase 2 study. The primary outcome is Time From Randomization to First Documented AF Recurrence..

241
Enrollment
Phase 2
4
Arms
In the primary outcome
n/a
Effect
No re-analysis shown
n/a
95% CI
See limitations
FeatureRegistry value
ClinicalTrials.gov identifierNCT01534962
PhasePhase 2
ConditionPersistent Atrial Fibrillation
AllocationRandomized
Design modelParallel
MaskingQuadruple
Enrollment241
Arms in the primary outcome4
Lead sponsorMenarini Group
Results postedYes

2. Clinical Question

Population

Patients with persistent atrial fibrillation who had successful electrical cardioversion. The primary endpoint population included randomized patients who took at least one dose of study medication; the registry record reports N=238 for that population and notes that 3 randomized patients were excluded.

Intervention

Three oral, twice-daily ranolazine regimens: low, intermediate, and high dose. The record describes the study as dose-ranging but does not report the actual dose amounts.

Comparator

Oral placebo, given twice daily. The trial used a placebo-controlled design, with four parallel treatment groups.

Primary question

How long after randomization did it take for a first atrial fibrillation recurrence to be documented, and how did the time-to-recurrence results across the ranolazine dose groups compare with placebo during 16 weeks (112 days) of follow-up?

The trial focused on maintaining sinus rhythm after cardioversion rather than on the immediate success of the cardioversion procedure. Participants reported trans-telephonic ECGs daily to a central ECG facility. A recurrence could also be documented by a 12-Lead ECG at the study site; the primary endpoint used whichever of those sources recorded recurrence first.

The record also lists outcomes based on the number of patients with documented or confirmed recurrences, including an outcome restricted to patients in sinus rhythm 48 hours after cardioversion. Those outcomes address related but distinct questions: whether a recurrence was recorded during follow-up, whether it was confirmed, and how those counts looked in a defined post-cardioversion subgroup. They do not replace the primary time-to-first-recurrence question.

3. Trial Design

This was a randomized, parallel-group, placebo-controlled Phase II study sponsored by Menarini Group. The registry record describes quadruple masking and a double-blind, double-dummy design. It lists enrollment of 241 and a completed study. The study began in 2012-01, and primary completion was recorded as 2013-10.

Following successful electrical cardioversion, participants were randomized to low-dose, intermediate-dose, or high-dose oral ranolazine, or oral placebo. Each regimen was given twice daily. The registry record does not report the dose amounts, allocation ratio, or details of the randomization procedure.

Maximum treatment duration was 112 days (16 weeks). Participants reported trans-telephonic ECGs daily to a central core ECG facility, and study-site 12-Lead ECGs could also document recurrence. The primary endpoint definition uses the first of those sources to report atrial fibrillation recurrence. Patients who discontinued without a documented recurrence were censored at the time of their last available ECG.

The primary analysis population is described as an intention-to-treat approach that included all randomized patients who took at least one dose of study medication. The registry record reports N=238 for this population and says this excluded 3 randomized patients. The denominators for some secondary outcomes differ, including the outcome limited to patients in sinus rhythm 48 hours after cardioversion. The record does not report the reasons for those differences or a full account of participant flow by treatment group.

The trial was described as dose-ranging, but the registry record does not report a statistical plan, sample-size justification, planned interim analyses, or a prespecified approach to comparing the dose groups. These omissions limit what can be inferred about the planned hierarchy of analyses or the role intended for each dose comparison.

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: A total of 310 patients were screened and underwent cardioversion (CV). Of these, 241 were still in sinus rhythm 2 hours post-CV and, thus, were eligible for randomization. Patients who experienced an atrial fibrillation (AF) recurrence could continue the study if no medical intervention was needed and otherwise had to discontinue the study.

Overall Study

StageRanolazine Low DoseRanolazine Intermediate DoseRanolazin High DosePlacebo
STARTED67605856
COMPLETED30343424
NOT COMPLETED37262432

Reasons for not completing this period:

ReasonRanolazine Low DoseRanolazine Intermediate DoseRanolazin High DosePlacebo
Randomized but did not start treatment2001
Discontinued at AF recurrence35262431

Analysis population for the primary outcome, as defined in the registry: Intention-to-treat-approach that analyzed all randomised patients who took at least one dose of study medication (N=238, i.e. excluding 3 randomized patients).

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.

Population: ITT-population (excluding 3 randomized patients who never started study drug)

CharacteristicUnitRanolazine Low DoseRanolazine Intermediate DoseRanolazin High DosePlaceboTotal
Participants analysed65605855238
Age, Continuousyears66.9 (SD 11.8)65.5 (SD 8.5)63.6 (SD 11.3)65.2 (SD 9.5)65.3 (SD 10.4)
Sex: Female, Male: FemaleParticipants199121454
Sex: Female, Male: MaleParticipants46514641184
Time since AF diagnosismonths10.5 (SD 24.0)7.2 (SD 12.9)15.5 (SD 28.2)6.9 (SD 13.5)10.0 (SD 20.7)

6. Primary Endpoint

The registry lists the primary outcome as Time From Randomization to First Documented AF Recurrence., measured over 16 weeks (112 days).

ElementRegistry entry
Result typeMedian
Measure of spread95% Confidence Interval
UnitDays
Endpoint classificationTime-to-Event Analysis

The primary endpoint was time from randomization to the first documented atrial fibrillation recurrence, measured in days. It combined patient-reported trans-telephonic ECG evidence with 12-Lead ECG evidence obtained at the study site, using whichever occurred first. The registry record specifies a timeframe of 16 weeks (112 days).

A time-to-event endpoint captures both whether an event occurred and when it was first recorded. It can therefore preserve information about the timing of recurrence that a simple event count over follow-up would not convey. The reported summary measure is the median time to recurrence, with a 95% confidence interval. In general, a confidence interval describes uncertainty around an estimate; its width reflects how precisely the estimate is determined by the data and analysis.

Participants who discontinued without atrial fibrillation were censored at the last available ECG. In general, censoring means that the exact event time is unknown for a participant after observation ends, while the observed follow-up up to that point can still contribute information. Interpretation depends on the analysis approach and assumptions about why follow-up ended; those details beyond the stated censoring rule are not reported in the registry record.

The registry record does not provide complete median and confidence-interval information for every group: the intermediate-dose median is missing, and the confidence-interval bounds are incomplete for the reported groups. It also does not report sponsor comparative hazard ratios. Consequently, the posted group summaries do not support a complete interpretation of the primary endpoint across all dose comparisons.

7. Why No Re-analysis Is Shown

Reported as posted, not recalculated. Values missing or not estimable for a two-arm comparison (median time 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 primary endpoint summaries are incomplete. The record reports a median time to first documented recurrence of 51.0 days for low-dose ranolazine, 117.0 days for high-dose ranolazine, and 58.0 days for placebo. For intermediate-dose ranolazine, the median itself is not reported in the registry record. The confidence-interval information is also incomplete: only a lower bound is listed for each group, with no upper bound reported. These limitations prevent a full assessment of the precision of the group medians.

A longer reported median in one group should not be read by itself as evidence of a treatment effect. A comparison of time-to-event outcomes ordinarily depends on an appropriate comparative analysis that uses event timing and accounts for censoring. The registry record does not report sponsor hazard ratios or other comparative primary-endpoint analyses. It also identifies the values as insufficient or not estimable for a two-arm recalculation of this median-time outcome. No recalculated primary comparison is therefore presented.

For the secondary recurrence outcomes, the posted counts and unadjusted recalculations show differing patterns across outcomes and dose groups. The risk-difference confidence intervals for the posted comparisons generally span no difference; one comparison in the subgroup in sinus rhythm 48 hours after cardioversion has a risk-difference interval that does not span zero and an unadjusted p-value of 0.042. That is an unadjusted secondary finding, not a substitute for a reported primary analysis. The registry record does not report sponsor analyses for these comparisons.

These secondary estimates should be treated as exploratory. They are based on posted summary counts, are unadjusted for multiple comparisons, and do not establish a consistent pattern across the several recurrence definitions. The registry record does not state whether the comparisons were prespecified or how multiplicity was to be handled. Without that context, an isolated nominal result carries less weight than a prespecified primary analysis with complete estimates and uncertainty intervals.

The posted safety counts describe serious and other adverse events recorded during the study, but they do not establish that an event was caused by a study treatment. The record does not provide a complete account of event timing, duration, severity grading, or the sponsor's assessment of relatedness in the information summarized for these outcomes. The safety figures should therefore be read as descriptive counts, not as comparative proof of safety or harm.

9. Statistical Methods Explained

The primary endpoint is a time-to-event outcome. Its event is the first documented atrial fibrillation recurrence after randomization. A median time summarizes the point at which half of the relevant event-time distribution lies on either side, subject to the endpoint's analysis and censoring rules. It is not the same as an average follow-up time, nor does it by itself compare randomized groups.

Why use time-to-event analysis?

Participants may have different observed follow-up times, and some may leave the study without a documented recurrence. Time-to-event methods can use the time observed before follow-up ends rather than treating all participants as if they had identical observation. Here, the registry record says that participants who discontinued without atrial fibrillation were censored at their last available ECG. In general, censoring preserves partial follow-up information, but the analysis also requires appropriate methods and assumptions. The registry record does not report the specific estimator, model, or assumptions used for the primary outcome.

The record reports group medians and labels the dispersion as a 95% confidence interval. A confidence interval represents uncertainty around an estimate under the analysis method; it is not a range guaranteed to contain the true value. The primary summaries are incomplete: the intermediate-dose median is missing, and only lower confidence-interval bounds are listed. There are no sponsor-reported comparative hazard ratios in the registry record. Since the median-time values are missing or not estimable for a two-arm comparison, a recalculated comparison is not appropriate.

How to read the secondary comparisons?

The secondary outcomes include event counts, which can be expressed as the number of participants with a recorded recurrence in each group. The recalculated comparisons use risk differences: the difference between the observed event proportions in a treatment group and placebo. A negative risk difference means the observed proportion was lower in the treatment group; a positive one means it was higher. These are unadjusted recalculations from the posted summary counts, not sponsor-reported analyses. The registry record lists no reported analyses for the secondary outcomes.

Each risk difference is accompanied by a confidence interval. In general, an interval that spans zero is compatible with no difference as well as with differences in either direction, given the analysis and its uncertainty. A p-value describes how unusual data at least as incompatible with a specified null hypothesis would be under that hypothesis and the test assumptions. It does not measure the probability that a treatment effect is real, and it does not describe clinical importance. The posted p-values are unadjusted; they do not account for the number of outcomes and comparisons considered.

Risk ratios and odds ratios are additional ways to express binary-outcome comparisons. A risk ratio compares event proportions, while an odds ratio compares event odds. Their interpretation depends on the outcome frequency and the measure used. The registry record contains these measures in the recalculated comparisons, but they should not be treated as sponsor analyses or as a replacement for a prespecified analysis plan.

What the planning illustrations mean

The sample-size planning illustrations are based on the observed effect, with assumed two-sided significance level 0.05, equal allocation between two arms, and a normal approximation. They give illustrative participants per arm for 80% or 90% power when targeting the stated fraction of the observed effect. They are not the trial's original design calculation, do not describe observed power, and do not show that the study was adequately powered for its primary endpoint. The registry record does not report the trial's own sample-size justification.

Planning calculations based on an observed effect can be unstable, especially when the estimate is imprecise. A small or uncertain observed difference can produce very large planning estimates, while a noisy estimate can also exaggerate the apparent effect used in the calculation. These figures should be interpreted as hypothetical planning illustrations under their stated assumptions, not as a retrospective verdict on the trial or as evidence about the treatment.

Which analyses take precedence?

The posted recalculations are unadjusted and use the available summary statistics. The record does not report sponsor statistical analyses for the secondary endpoints, while the primary comparative hazard ratios are also not reported. The displayed inferential results should therefore be distinguished from a full sponsor analysis, which could use participant-level data, prespecified models, covariate adjustments, or other details unavailable in the registry record. The record does not report those methods, so their influence cannot be assessed.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists multiple secondary recurrence outcomes, including distinctions between documented and confirmed events and a subgroup defined by sinus rhythm 48 hours after cardioversion. Multiple outcomes and treatment comparisons create a multiplicity concern: when many statistical tests are considered, the chance of at least one apparently unusual result can increase. The registry record does not report whether the secondary outcomes were prespecified in a hierarchy, whether any multiplicity adjustment was planned, or whether the posted p-values were intended as confirmatory.

The secondary p-values in the recalculations are unadjusted. They should be read as individual comparisons, not as a family-wise assessment of all outcomes and doses. One unadjusted comparison has p = 0.042, but that value alone does not establish a reliable overall pattern across the secondary outcomes. The record also does not report sponsor analyses for these outcomes.

The primary analysis population is described as all randomized patients who took at least one dose of study medication, an intention-to-treat approach with that stated eligibility condition. The record reports N=238 and says 3 randomized patients were excluded. It does not report a separate analysis including every randomized patient regardless of whether they took study medication, or explain the reasons for exclusion.

For the primary time-to-event outcome, the stated rule is to censor participants who discontinued without atrial fibrillation at their last available ECG. The record does not report the amount or pattern of missing ECG data, reasons for discontinuation, sensitivity analyses, or additional methods for handling missing outcome data. It also does not report how missing data were handled for the secondary event counts.

The denominators for the subgroup outcome among patients in sinus rhythm 48 hours after cardioversion differ from the denominators for the broader recurrence outcomes. The record identifies the subgroup but does not explain the participant flow into it or report whether subgroup analyses were prespecified. No interim analyses or stopping rules are reported in the registry record.

11. Safety Results

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

ArmParticipants with serious adverse eventsParticipants at riskPercentage
Ranolazine Low Dose2653.1%
Ranolazine Intermediate Dose3605.0%
Ranolazin High Dose3585.2%
Placebo4557.3%
Participants with at least one serious adverse event
Serious adverse events by armRanolazine Low Dose3.1%Ranolazine Intermediate Dose5.0%Ranolazin High Dose5.2%Placebo7.3%% 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
Ranolazine Low Dose51 of 65
Ranolazine Intermediate Dose46 of 60
Ranolazin High Dose42 of 58
Placebo41 of 55

Most frequent serious adverse event terms

Event termOrgan systemRanolazine Low DoseRanolazine Intermediate DoseRanolazin High DosePlacebo
Angina PectorisCardiac disorders0 of 651 of 600 of 581 of 55
HypertensionVascular disorders1 of 650 of 600 of 581 of 55
PancreatitisGastrointestinal disorders1 of 650 of 600 of 580 of 55
HepatitisHepatobiliary disorders1 of 650 of 600 of 580 of 55
Acute Coronary SyndromeCardiac disorders0 of 651 of 600 of 580 of 55
Angina unstableCardiac disorders0 of 651 of 600 of 580 of 55
Atrial FibrillationCardiac disorders0 of 650 of 600 of 581 of 55
Atrial FlutterCardiac disorders0 of 650 of 601 of 580 of 55
Coronary Artery DiseaseCardiac disorders0 of 651 of 600 of 580 of 55
Sick Sinus SyndromeCardiac disorders0 of 650 of 600 of 581 of 55

Most frequent non-serious adverse event terms

Event termOrgan systemRanolazine Low DoseRanolazine Intermediate DoseRanolazin High DosePlacebo
Atrial FibrillationCardiac disorders29 of 6524 of 6023 of 5827 of 55
PalpitationsCardiac disorders9 of 6511 of 6011 of 586 of 55
FatigueGeneral disorders11 of 6510 of 609 of 585 of 55
DizzinessNervous system disorders6 of 652 of 6014 of 587 of 55
Chest PainGeneral disorders8 of 657 of 604 of 586 of 55
DyspnoeaRespiratory, thoracic and mediastinal disorders5 of 657 of 605 of 586 of 55
AstheniaGeneral disorders4 of 651 of 605 of 582 of 55
HeadacheNervous system disorders2 of 652 of 605 of 582 of 55
NauseaGastrointestinal disorders5 of 651 of 604 of 580 of 55
VertigoEar and labyrinth disorders1 of 651 of 604 of 582 of 55

Serious events with the highest arm-level rate: angina pectoris (1.8%), atrial fibrillation (1.8%), sick sinus syndrome (1.8%), ventricular tachycardia (1.8%), sudden death (1.8%).

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 registry record reports serious adverse events affecting 2 participants in the low-dose group, 3 in the intermediate-dose group, 3 in the high-dose group, and 4 in the placebo group. Other adverse events affected 51, 46, 42, and 41 participants in those groups, respectively. These are descriptive counts; they do not by themselves show whether a treatment caused an event or establish a comparative safety difference.

The record lists Angina Pectoris, Atrial Fibrillation, Sick Sinus Syndrome, Ventricular Tachycardia, Sudden Death, and Hypertension among the serious adverse event terms, each with a listed frequency of 1.8%. These term-level figures should not be interpreted as treatment-specific rates without further detail on their distribution and coding. The registry record does not report death counts in the outcome information.

In general, safety comparisons depend on consistent event definitions, observation time, severity, relatedness assessment, and complete reporting. Those details are not reported in the registry record for these summaries. The counts therefore describe what was recorded, but do not support conclusions about causation or establish that one regimen is safer than another.

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

The posted results describe a randomized study of three ranolazine dose regimens and placebo after successful electrical cardioversion for persistent atrial fibrillation. They include group summaries for time to first documented recurrence, counts for several secondary recurrence outcomes, and adverse-event counts. The primary outcome is clinically and statistically distinct from an event count because it includes the timing of the first recurrence and accounts for censored follow-up under the stated rule.

The primary summaries do not provide a complete basis for comparing the groups. The intermediate-dose median is missing, the confidence-interval bounds are incomplete, and sponsor-reported comparative hazard ratios are not reported in the registry record. The record does not support a recalculated two-arm comparison for this median-time endpoint. Consequently, the reported group medians alone cannot establish whether the time-to-recurrence distributions differed between ranolazine and placebo.

The secondary event-count comparisons provide additional descriptive information, but they are unadjusted recalculations and cover multiple outcomes. Their pattern is not uniform, and the registry record does not report a prespecified multiplicity strategy or sponsor analyses. The isolated unadjusted result should not be treated as definitive evidence. Event counts also do not answer the same timing question as the primary endpoint.

These results do not establish that ranolazine does or does not maintain sinus rhythm, nor do the safety counts establish that a treatment caused or prevented adverse events. The record contains incomplete primary-endpoint information and does not report important analysis details, including the trial's statistical plan and sample-size justification. Conclusions about efficacy or comparative safety would require a complete, appropriately analyzed clinical report and cannot be drawn from the posted registry summaries alone.

13. Why This Trial Matters Statistically

This trial illustrates why an endpoint's type determines what a useful analysis must report. A median time-to-event summary is not enough to establish a comparison between randomized groups, particularly when censoring is part of the endpoint and the reported confidence intervals are incomplete. Comparative hazard ratios or another appropriate sponsor analysis would be needed to interpret the primary question more fully, but those results are not reported in the registry record.

It also shows how secondary outcomes can answer adjacent but different questions. Counts of participants with recurrence are easier to describe, but they discard the timing information that defines the primary endpoint. When several recurrence definitions and dose comparisons are examined, unadjusted p-values should be treated cautiously, especially when the registry record does not explain prespecification or multiplicity handling.

The record's analysis population and endpoint-specific denominators matter as well. The primary outcome used randomized patients who took at least one dose, while the subgroup outcome had different group denominators. Clear participant flow and missing-data methods are important for understanding what each estimate represents; those details are not fully reported in the registry record.

Finally, planning illustrations based on observed effects are not evidence of observed power and are not the trial's original design justification. Their assumptions should be distinguished from the study's actual planning, which is not reported. Taken together, these features make the record useful for understanding the trial question and the limits of registry summaries, while underscoring the importance of complete endpoint reporting and a transparent statistical plan.

14. Limitations

The most important trial-specific limitation in the registry record is incomplete reporting of the primary time-to-event outcome. The intermediate-dose median is missing, the listed confidence-interval bounds are incomplete, and no sponsor comparative hazard ratios are reported. The available summaries therefore do not permit a complete comparison of the primary endpoint across the randomized groups.

The registry record also does not report the statistical analysis plan, the estimator or model for the primary endpoint, or the trial's sample-size justification. Without those details, it is not possible to establish which comparisons were prespecified, how the dose-ranging question was structured, or what degree of precision the study was designed to achieve.

Secondary results are incomplete as well. Five secondary outcomes are listed, while results are not reported in the registry record for some listed outcomes. Recalculated comparisons are available for only some dose groups and outcomes. The posted secondary comparisons are unadjusted, and the record does not describe a multiplicity strategy. This limits the strength of any interpretation based on a nominal p-value or apparent pattern across endpoints.

The primary population excludes randomized patients who did not take at least one dose, and the record does not report the reasons for those exclusions. It gives a censoring rule for participants who discontinued without atrial fibrillation, but does not describe missing ECG data, reasons for discontinuation, or sensitivity analyses. The subgroup denominators differ from those of the broader outcomes, without a full account of subgroup formation.

The safety summaries are counts without the additional detail needed to assess relatedness, severity, timing, or comparative exposure. The registry record also does not report the actual ranolazine dose amounts. These reporting limitations do not establish that the conduct or analysis was flawed, but they constrain what can be concluded from the registry record.

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18. Record Summary

NCT01534962 is a completed, randomized, quadruple-masked, parallel-group Phase II study sponsored by Menarini Group. It enrolled 241 participants with persistent atrial fibrillation and evaluated low-, intermediate-, and high-dose oral ranolazine, each given twice daily, against twice-daily oral placebo after successful electrical cardioversion.

The primary outcome was time from randomization to first documented atrial fibrillation recurrence during 16 weeks (112 days). The stated analysis population included randomized patients who took at least one dose, reported as N=238, excluding 3 randomized patients. Daily trans-telephonic ECG reports and study-site 12-Lead ECGs could document recurrence; participants discontinuing without recurrence were censored at their last available ECG.

Primary endpoint summaries are incomplete, and sponsor comparative analyses are not reported in the registry record. Secondary recurrence counts and safety counts are available, but the secondary recalculations are unadjusted and the registry record does not report a multiplicity approach or full statistical plan. Interpretation is therefore limited to the posted summaries and their stated uncertainties.

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