Trial Comparing the Efficacy and Safety of Lacosamide (LCM) to Carbamazepine Controlled-Release (CBZ-CR); Initial Monotherapy in Epilepsy; Subjects Aged 16 and Older: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Trial Comparing the Efficacy and Safety of Lacosamide (LCM) to Carbamazepine Controlled-Release (CBZ-CR); Initial Monotherapy in Epilepsy; Subjects Aged 16 and Older (NCT01243177), a randomized phase 3 study. The primary outcome is Proportion of Subjects in the Full Analysis Set (FAS) Remaining Seizure Free for 6 Consecutive Months (26 Consecutive Weeks) of Treatment Following Stabilization at the Last Evaluated Dose for Each Subject.

2. Clinical Question

This was an active-comparator question rather than a comparison against no treatment or placebo. The posted primary endpoint is a proportion: it describes the estimated share of participants who met the specified period of seizure freedom. It does not by itself summarize every aspect of seizure control, tolerability, or treatment experience. The registry also lists remaining seizure free for 12 consecutive months as a secondary outcome, which asks about a longer sustained interval than the primary endpoint.

3. Trial Design

The registry describes a completed phase 3, randomized, parallel-group, triple-masked study sponsored by UCB BIOSCIENCES GmbH. It enrolled 888 participants. The recorded start was 2011-04, and primary completion was 2015-07. Participants were assigned to lacosamide or controlled-release carbamazepine as monotherapy. The official title describes the study as multicenter, double-blind, double-dummy, randomized, and positive-controlled. The registry’s masking field is recorded as triple; further details about which parties were masked are not reported in the registry record.

The posted primary analysis uses the Full Analysis Set, defined as randomized participants who took at least 1 dose of study medication. The arm-level records list 444 participants for lacosamide and 442 for controlled-release carbamazepine. These are the analysis denominators recorded with the posted outcome; they should not be treated as evidence about other analysis populations or follow-up availability.

The primary endpoint was the proportion remaining seizure free for 6 consecutive months, or 26 consecutive weeks, following stabilization at the last evaluated dose for each participant. The registry says that this proportion was estimated using Kaplan-Meier methods. The listed secondary outcome concerns seizure freedom for 12 consecutive months, or 52 consecutive weeks, following stabilization at the last evaluated dose.

The trial description identifies noninferiority as the design objective, but the original protocol’s margin, sample-size justification, planned interim analyses, and detailed statistical analysis plan are not reported in the registry record. The registry record also does not provide a fuller account of dose adjustment, stabilization rules, or the timing and conduct of follow-up assessments. Those omissions limit how precisely the posted summary can be connected to the full protocol.

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: Participant Flow refers to the Safety Analysis Set which is defined as all randomized subjects who took at least 1 dose of study medication and is identical with the Full Analysis Set.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Full Analysis Set (FAS), consisting of all randomized subjects who took at least 1 dose of study medication.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

Population: Baseline Characteristics refer to the Safety Analysis Set which is defined as all randomized subjects who took at least 1 dose of study medication and is identical with the Full Analysis Set.

6. Primary Endpoint

The registry lists the primary outcome as Proportion of Subjects in the Full Analysis Set (FAS) Remaining Seizure Free for 6 Consecutive Months (26 Consecutive Weeks) of Treatment Following Stabilization at the Last Evaluated Dose for Each Subject, measured over 6 consecutive months (26 consecutive weeks) of treatment following stabilization at the last evaluated dose for each subject.

The primary endpoint measures the proportion of participants who remained seizure free for 6 consecutive months, defined as 26 consecutive weeks of treatment following stabilization at the last evaluated dose for each participant. Its population is the Full Analysis Set, comprising randomized participants who took at least 1 dose of study medication. The registry describes the endpoint as estimated with Kaplan-Meier methods, and reports arm-level estimates with 95% confidence intervals.

This endpoint focuses on sustained seizure freedom over a specified treatment period rather than counting all seizures or measuring the time to a first seizure alone. As a general statistical explanation, a time-to-event method such as Kaplan-Meier can use information about how long participants are observed before an event or the end of follow-up, while accounting for participants whose event status is not observed through the full period. The registry does not report the detailed event and censoring rules used for this analysis, so the exact implementation cannot be reconstructed from the record.

The endpoint is relevant to the stated comparison because the study sought to assess seizure freedom during monotherapy. It is nevertheless one defined outcome, not a complete summary of clinical benefit or harm. Its interpretation should stay within the population, treatment period, and seizure-free definition recorded for the analysis.

7. Results Posted in the Registry

• Lacosamide: 89.9% (399/444) versus 91.2% (403/442) on control; risk difference -1.3 percentage points (95% CI -5.2 to 2.5), risk ratio 0.99 (0.94–1.03); unadjusted two-proportion z-test p = 0.505.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Proportion of Subjects Remaining Seizure Free for 12 Consecutive Months (52 Consecutive Weeks) Following Stabilization at the Last Evaluated Dose for Each Subject

• Endpoint type: Binary: the percentage of participants with the event (counts rebuilt from the posted percentages and group sizes).
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Lacosamide: 77.7% (345/444) versus 82.8% (366/442) on control; risk difference -5.1 percentage points (95% CI -10.3 to 0.1), risk ratio 0.94 (0.88–1.00); unadjusted two-proportion z-test p = 0.056.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Lacosamide and the control. The interval gives the range of effects that remain compatible with the data.

The registry posts one secondary outcome: the proportion remaining seizure free for 12 consecutive months, or 52 consecutive weeks, following stabilization at the last evaluated dose. It uses the same general kind of outcome as the primary endpoint, but requires a longer sustained seizure-free interval. The result is therefore related to the primary question while representing a more demanding duration criterion.

Across the primary and secondary outcomes, the broad pattern is that the posted arm estimates are numerically higher for controlled-release carbamazepine than for lacosamide. The secondary result does not reverse that direction. However, the longer-duration endpoint is not a simple repeat of the primary endpoint: it represents a different follow-up horizon, and uncertainty around its comparison must be considered on its own. The detailed endpoint estimates and intervals are reported with the outcome results and are not a substitute for a prespecified overall interpretation.

There is only one secondary outcome with posted detailed results in the registry record. The record does not report a multiplicity adjustment or a complete plan for controlling the chance of false-positive findings across outcomes. As a general statistical explanation, when many outcomes or comparisons are examined, the probability of at least one apparently notable result can increase unless the analysis plan accounts for multiple testing. Secondary results are often best viewed as supportive or exploratory when their inferential status and multiplicity handling are not clear.

The secondary endpoint should therefore be interpreted alongside, but not allowed to replace, the primary endpoint. It can add information about a longer period of seizure freedom, yet it does not independently settle the trial’s noninferiority question. The registry does not report enough detail about multiplicity, analysis hierarchy, or prespecification to assign the secondary finding a definitive confirmatory role.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Proportion of Subjects Remaining Seizure Free for 12 Consecutive Months (52 Consecutive Weeks) Following Stabilization at the Last Evaluated Dose for Each Subject

9. Statistical Interpretation

10. Statistical Methods Explained

The registry reports arm-level percentages, confidence intervals, and a separate comparison between lacosamide and controlled-release carbamazepine. These statistics answer related but distinct questions: the arm estimates describe the observed endpoint within each group, while a comparison statistic describes the estimated contrast between groups. The trial’s stated noninferiority objective requires attention to the contrast and to a prespecified decision margin, not just inspection of the two percentages.

What does the Kaplan-Meier estimate represent?

The primary endpoint is the proportion remaining seizure free for 6 consecutive months after stabilization at the last evaluated dose. The registry says this proportion was estimated using Kaplan-Meier methods. In general, Kaplan-Meier estimation is used for time-to-event data, where participants may have different lengths of observation. It estimates the event-free pattern over time while incorporating information from participants whose follow-up ends before their event status is known for the full period. This approach relies on rules for defining the event, censoring, and time origin. The registry record does not report the full operational details of those rules.

The posted percentage is therefore not necessarily a simple division of an event count by the arm denominator. The record’s endpoint description explicitly identifies a Kaplan-Meier estimate, and the arm results should be read as time-to-event estimates with confidence intervals. The registry lists the Full Analysis Set as randomized participants who took at least 1 dose of study medication. It does not provide a full account of how participants with incomplete follow-up, treatment discontinuation, or other missing endpoint information were handled.

How should the confidence intervals be read?

A confidence interval gives a range of values compatible with the data under the statistical method used, while reflecting sampling uncertainty. It is not a guarantee that the true value lies in the interval, nor does it describe the range of individual participant outcomes. For the primary arm estimates, the registry reports 95% confidence intervals. Those intervals communicate uncertainty around each estimated proportion. Comparing two separate arm intervals visually is not a replacement for a confidence interval or test for the between-arm contrast.

The recalculated comparison is an unadjusted risk difference based on posted summary statistics. A risk difference compares the estimated probability of the outcome between groups on an absolute scale. The recalculation reports p = 0.505, and its interval spans no difference. As a general statistical explanation, a p-value is a measure of how compatible the observed data are with a specified null hypothesis under the analysis assumptions; it is not the probability that the null hypothesis is true. The unadjusted result does not by itself test the trial’s noninferiority objective.

What is the role of the sponsor-reported analysis?

The registry reports a Mantel Haenszel analysis labelled Mean Difference (Final Values), with an estimate of -1.3 and a 95% confidence interval from -5.5 to 2.8. The method and displayed estimate are reported, but the registry does not provide a p-value or a complete description of the analysis details. The sponsor-reported result and the unadjusted recalculation should be kept distinct because they are reported using different analysis descriptions. The recalculation is not a replacement for the sponsor’s own analysis.

In a noninferiority study, the key inferential question is whether the confidence interval satisfies a prespecified margin in the direction and scale defined by the protocol. A conventional difference test that does not reject no difference cannot establish that the treatments are sufficiently similar. The registry states the noninferiority aim but does not report the margin, its justification, or enough detail to reproduce the full decision procedure. Therefore, the posted summary supports describing the estimates and uncertainty, but not independently validating the noninferiority criterion.

Why can over-dispersion matter?

As a general statistical explanation, over-dispersion occurs when the variability in data is greater than a model assumes. It can make standard errors and confidence intervals too small if the model does not allow for that extra variation. That concern commonly arises in analyses of counts or clustered observations. The primary endpoint is described as a Kaplan-Meier estimate of seizure-free proportions; the registry does not report an over-dispersion model for this endpoint. It would therefore be inappropriate to assume that over-dispersion was present or that a particular correction was used.

What can be inferred from the analysis record?

The registry lists 6 outcome measures and reports 2 analyses. It gives a detailed primary endpoint result and one secondary outcome result. It does not report the full analysis plan, planned interim analyses, the original sample-size justification, or the handling of every missing-data scenario. Those details matter because they clarify which analyses were prespecified, how uncertainty was calculated, and whether the reported population and methods match the protocol. Without them, interpretation should be anchored to the stated endpoint definition, analysis population, reported estimates, and stated limitations rather than filling gaps with assumptions.

11. Confidence Intervals and Precision

The primary arm estimates are 89.8% for lacosamide and 91.1% for controlled-release carbamazepine. Their respective 95% confidence intervals are 86.8% to 92.8% and 88.2% to 94.0%. These intervals show that each arm estimate has uncertainty; they do not mean that the same range applies to the difference between arms.

The recalculated between-arm risk-difference interval spans no difference, and its reported unadjusted p-value is 0.505. This indicates that the posted summary does not give a precise estimate that excludes no difference under that unadjusted comparison. It does not establish equivalence, and it does not answer the noninferiority question without the trial’s prespecified margin and analysis criterion. The registry record does not report those details.

Precision concerns how narrowly an estimate is bounded by its uncertainty interval. A relatively narrow interval can still leave important values compatible with the data if the decision threshold is strict, and a point estimate should not be read in isolation from its interval. In this trial, the arm-level confidence intervals are reported separately from the sponsor’s Mantel Haenszel result. The sponsor-reported interval is -5.5 to 2.8 around an estimate of -1.3; a p-value is not reported for that result.

Confidence intervals describe uncertainty under the analysis used and its assumptions. They do not account for every source of uncertainty, such as limitations in outcome ascertainment, missing-data handling, or incomplete reporting of the protocol. The registry’s incomplete detail about those features limits how fully the numerical precision can be assessed.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning illustrations give participants per arm for the binary outcomes in this record. They are not total-event counts: the sample size assumptions field specifies that total events apply to time-to-event tables, while all other planning figures are participants per arm. The assumptions stated for these illustrations are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is a stated fraction of the observed effect. The original trial’s own design assumptions and sample-size justification are not reported in the registry record.

For the primary outcome, the illustration based on 100% of the observed effect gives 7,829 participants per arm for 80% power and 10,480 participants per arm for 90% power. Planning for 75% of the observed effect gives 13,703 participants per arm for 80% power and 18,344 participants per arm for 90% power. Planning for 50% of the observed effect gives 30,345 participants per arm for 80% power and 40,623 participants per arm for 90% power.

The secondary outcome’s corresponding figures are 955 and 1,277 participants per arm when planning for 100% of its observed effect; 1,656 and 2,216 when planning for 75%; and 3,631 and 4,860 when planning for 50%, for 80% and 90% power respectively. In plain terms, the 80% column represents a planning target of an 80% chance of detecting the specified effect under the stated assumptions if that effect is real; the 90% column uses a higher detection-probability target. Smaller effects need more participants to detect, which is why the figures rise as the planned fraction of the observed effect falls.

These are sample-size planning illustrations based on the observed effects, not observed power. They do not show what power the completed trial achieved, and they are not evidence that the original trial was planned using these assumptions.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.912; treatment proportion p₁ = 0.899; average p̄ = 0.905.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.4143 = 0.8119.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.4142 = 0.3486.
4. n = (0.8119 + 0.3486)² / (-0.0131)² = 7,828.7, rounded up to 7,829 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
p0 <- 0.911764705882353                          # control proportion
p1 <- 0.898648648648649                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(1243177)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 7,829 (80% power), 10,480 (90% power)
 75% of observed effect: n per arm = 13,703 (80% power), 18,344 (90% power)
 50% of observed effect: n per arm = 30,345 (80% power), 40,623 (90% power)
power.prop.test: 7828.7 
Simulated power at n = 7,829 per arm: 0.800 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Analyses Reported by the Sponsor

The registry’s sponsor-reported analysis is a Mantel Haenszel result labelled Mean Difference (Final Values). It gives an estimate of -1.3 and a 95% confidence interval from -5.5 to 2.8. The registry does not report a p-value for this analysis. The unadjusted recalculation, by contrast, is a risk-difference comparison derived from the posted summary statistics and reports p = 0.505. These are not interchangeable presentations: they are identified by different analysis descriptions and should be read separately.

The trial description identifies noninferiority as the study objective. The sponsor-reported analysis is the registry’s reported analysis, while the recalculation is a simple unadjusted re-analysis of summary data. Neither the displayed estimate nor the recalculated p-value can establish the noninferiority conclusion without the prespecified margin and decision procedure. The registry record does not report the margin, its justification, or enough detail to reproduce the full sponsor analysis.

The discrepancy indicator is false, so the record does not flag a conflict between the reported analysis and recalculation. That does not make them the same analysis or remove the need to interpret each according to its method and scale. The sponsor-reported interval and the recalculated comparison both carry uncertainty; the registry’s limited methodological detail constrains independent assessment of how the sponsor result was obtained.

15. Multiplicity, Missing Data and Analysis Populations

The registry identifies the primary endpoint and lists a secondary endpoint, but it does not report a complete statistical analysis plan describing how multiple outcomes, analyses, or interim looks were handled. The record lists 6 outcome measures, while detailed secondary results are posted for one secondary outcome. It is not reported in the registry record whether there was a formal hierarchy among outcomes or a multiplicity adjustment. Without such information, secondary findings should not be interpreted as if they were necessarily protected by a prespecified family-wise testing strategy.

The Full Analysis Set is defined as all randomized participants who took at least 1 dose of study medication. This definition clarifies who was included in the posted primary population, but it does not provide a complete account of missing data. The registry does not report how missing seizure assessments, incomplete follow-up, withdrawal, or other departures from observation were handled in the Kaplan-Meier analysis. It also does not report sensitivity analyses for alternative missing-data assumptions.

For a time-to-event estimate, the handling of participants whose event status is not known through the endpoint period can affect the estimate. As a general explanation, censoring is a way of incorporating partial follow-up, but its use depends on assumptions about how follow-up ends and how that relates to the outcome. The record identifies Kaplan-Meier methods, but it does not give the detailed censoring rules or diagnostics needed to evaluate those assumptions.

The registry describes a noninferiority design but does not report the noninferiority margin, the original sample-size justification, or the detailed test procedure. Planned interim analyses are also not reported in the registry record. These omissions do not negate the posted results, but they limit independent verification of whether the analysis followed the intended design and how the noninferiority conclusion was meant to be determined.

16. 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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: convulsion (0.9%), partial seizures with secondary generalisation (0.7%), cerebrovascular accident (0.5%), grand mal convulsion (0.5%), ischaemic stroke (0.5%).

The posted serious adverse event figures are counts of participants affected, with the number at risk listed for each arm. For lacosamide, 36 participants were affected among 444 at risk; for controlled-release carbamazepine, 46 were affected among 442 at risk. Other adverse events affected 165 of 444 participants in the lacosamide group and 181 of 442 participants in the controlled-release carbamazepine group. These are separate categories as recorded; the registry does not provide enough detail to determine overlap between them.

The leading serious adverse event terms listed in the record include convulsion at 0.9%, partial seizures with secondary generalisation at 0.7%, and cerebrovascular accident, grand mal convulsion, ischaemic stroke, and drug reaction with eosinophilia and systemic symptoms each at 0.5%. The record does not specify an arm for these listed term percentages, so they should not be assigned to one treatment group. Death counts are not reported in the registry record.

These summaries describe recorded adverse events in the trial; they do not establish causation or provide a complete account of event severity, timing, duration, or clinical context. The registry record does not report the timeframe for these safety counts in the details presented. The counts should be interpreted separately from the seizure-freedom endpoint.

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

The results describe a randomized comparison of lacosamide and controlled-release carbamazepine monotherapy in participants aged 16 and older who were newly or recently diagnosed with epilepsy and had the seizure types named in the official title. For the primary outcome, the posted Kaplan-Meier estimates of remaining seizure free for 6 consecutive months are 89.8% for lacosamide and 91.1% for controlled-release carbamazepine. The recalculated unadjusted comparison reports p = 0.505 and an interval that spans no difference.

Those figures do not show that the treatments are identical. A failure to demonstrate a difference in an unadjusted comparison is not proof of equivalence, and it is not by itself evidence of noninferiority. Noninferiority depends on a prespecified margin and an analysis that evaluates whether the uncertainty interval meets that margin. The registry states that noninferiority was the design aim, but the margin and detailed decision criterion are not reported in the registry record.

The posted results also do not mean that every participant experienced the group-average outcome, nor do they predict an individual result. They apply to the recorded analysis population, endpoint definition, and trial setting. The 12-month secondary outcome addresses a longer sustained seizure-free period, while the adverse-event summaries address a different aspect of the comparison. Neither should be collapsed into the primary endpoint.

The record does not provide enough detail to assess every aspect of missing-data handling, multiplicity, protocol implementation, or the full sponsor analysis. These limits matter when interpreting precision and the strength of any formal conclusion. The statistics support a careful description of the observed estimates and uncertainty; they do not, on their own, support a broader claim about all patients, all outcomes, or treatment decisions.

18. Why This Trial Matters Statistically

This trial illustrates why active-comparator studies require more than a side-by-side reading of arm percentages. The registry describes a noninferiority objective, where the central question is not simply whether a conventional test detects a difference. The interpretation depends on a clinically and statistically prespecified margin, the analysis scale, and a confidence interval assessed against that margin. Here, the registry records the objective but does not report the margin or full decision procedure, leaving an important part of the intended inference unavailable.

The endpoint also demonstrates the distinction between a proportion and a time-to-event estimate. Although results are expressed as percentages, the registry says Kaplan-Meier methods were used. That method can incorporate partial follow-up under its assumptions, so the displayed proportions should not automatically be treated as raw event-count fractions. Understanding the population definition and follow-up rules is essential to interpreting what those percentages represent.

The trial further shows why estimates and precision need to be read together. The arm estimates are close in the posted summary, but uncertainty remains around both individual estimates and their contrast. A point estimate alone cannot establish equivalence, and a p-value from a simple unadjusted recalculation cannot substitute for the sponsor’s reported method or a noninferiority analysis.

Finally, safety counts and a longer-duration secondary outcome broaden the descriptive record but do not automatically resolve the primary inferential question. Clear separation of primary and secondary outcomes, analysis methods, and limitations helps readers distinguish what is observed from what the design aimed to establish.

19. 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.
• Participant counts were reconstructed from posted percentages and arm sizes, so small rounding differences are possible.

Several trial-specific limitations in the registry record constrain interpretation. Although the study is described as a noninferiority trial, the noninferiority margin, its rationale, and the detailed decision rule are not reported. The original sample-size justification and any planned interim analyses are also not reported, so the planning illustrations based on observed effects cannot be used to infer the trial’s original design assumptions.

The primary endpoint is described as a Kaplan-Meier estimate, but the registry does not report the detailed event definition, censoring rules, or handling of incomplete seizure assessments and other missing data. The Full Analysis Set definition is available, but the record does not provide a full account of additional analysis populations or sensitivity analyses. This restricts independent assessment of how partial follow-up and missing outcomes may have influenced the results.

The sponsor-reported Mantel Haenszel analysis is identified by method and labelled Mean Difference (Final Values), but a p-value and fuller analysis details are not reported. The registry also does not describe the multiplicity strategy for the listed outcomes or analyses. These omissions limit the ability to determine how the reported result fits into a prespecified testing hierarchy.

The posted record does not provide detailed baseline characteristics, subgroup results, treatment adherence, reasons for discontinuation, or a full description of dose stabilization and follow-up procedures. Such information should not be assumed from the brief study description. For safety, the record lists serious and other adverse-event counts and selected serious-event terms, but death counts and the timeframe for these summaries are not reported in the registry record. These limitations do not erase the reported estimates; they define what can be confidently concluded from the registry summary.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Trial Comparing the Efficacy and Safety of Lacosamide (LCM) to Carbamazepine Controlled-Release (CBZ-CR); Initial Monotherapy in Epilepsy; Subjects Aged 16 and Older — NCT01243177.
• Registry record last updated 2021-02-02; status last verified 2021-01.
• Results first posted 2016-02-23.
• 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.

23. Record Summary

NCT01243177 is a completed phase 3 randomized, parallel-group, triple-masked, positive-controlled trial sponsored by UCB BIOSCIENCES GmbH. It enrolled 888 participants and compared lacosamide with controlled-release carbamazepine as monotherapy in participants aged 16 and older newly or recently diagnosed with epilepsy.

The primary outcome was the Kaplan-Meier-estimated proportion remaining seizure free for 6 consecutive months after stabilization at the last evaluated dose, in the Full Analysis Set. The posted estimates were 89.8% for lacosamide and 91.1% for controlled-release carbamazepine. The registry also reports a secondary 12-month seizure-freedom outcome and adverse-event summaries.

The study description states a noninferiority objective, but the noninferiority margin and detailed decision procedure are not reported in the registry record. The available results support interpretation of the posted estimates and their uncertainty, with those reporting limits kept in view.