A Placebo Controlled Trial of Dalfampridine ER for Ambulatory Activity in People With Multiple Sclerosis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Placebo Controlled Trial of Dalfampridine ER for Ambulatory Activity in People With Multiple Sclerosis (NCT01356940), a randomized phase 4 study. The primary outcome is Peak Activity Index.

2. Clinical Question

The trial asked whether ambulatory activity changed during treatment with dalfampridine ER compared with placebo in people with multiple sclerosis. Its primary outcome, Peak Activity Index, describes the 30 fastest minutes of walking during a 24-hour period, averaged over one week of accelerometer wear. The recorded measure was change from baseline to four weeks on intervention, expressed in strides per minute.

The crossover arrangement means that participants were assigned to treatment sequences rather than to a single treatment for the whole study. Each sequence included both interventions, separated by the stated washout. This is the clinical comparison the registry describes; details of the original statistical plan, including how it handled the crossover structure, are not reported in the registry record.

3. Trial Design

The registry record identifies this as a Phase 4, randomized, triple-masked, placebo-controlled crossover trial. It lists 43 participants as enrolled and the study status as completed. The recorded start was 2010-11, and primary completion was 2013-04. Multiple sclerosis is the listed condition.

Two sequences are described. In one, participants received dalfampridine ER 10mg bid for four weeks, had a two-week washout, and then received placebo for four weeks. In the other, participants received placebo bid for four weeks, had the same two-week washout, and then received dalfampridine ER 10mg bid. The primary outcome timeframe is recorded as 10 weeks. The registry labels the masking as triple but does not identify which roles were masked; that information is not reported in the registry record.

The primary outcome summaries list 43 observations for dalfampridine ER and 42 for placebo. These are outcome-specific counts, not a description of how many participants completed each treatment sequence. Reasons for the difference between the listed counts, sequence allocation numbers, adherence, withdrawals, and the analysis population are not reported in the registry record.

A crossover design can use within-participant comparisons, since each participant may contribute observations under both treatments. That design also makes period, sequence, and carryover considerations relevant to analysis. The posted arm summaries alone do not show how these features were handled. The registry lists one mixed-model analysis for the primary outcome, but the model specification and the original analysis plan are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

First Intervention (28 Days)

Reasons for not completing this period:

Washout (14 Days)

Second Intervention (28 Days)

Reasons for not completing this period:

5. Baseline Characteristics

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

6. Primary Endpoint

The registry lists the primary outcome as Peak Activity Index, measured over 10 weeks.

Peak Activity Index is a measure of walking activity derived from accelerometer wear. It is defined as the 30 fastest minutes of walking over a 24-hour period, averaged over one week of wear. The endpoint is recorded as change from baseline to four weeks on intervention, with units of change in strides per minute. A larger change represents a larger increase in this measured activity relative to baseline; it does not, by itself, establish a broader change in health or daily functioning.

Using the fastest walking minutes focuses the measure on periods of relatively high ambulatory activity rather than all movement throughout the day. Averaging over one week of wear is intended to represent activity across multiple observations rather than a single moment. Accelerometer-based measurement provides an objective activity measure, while the interpretation still depends on wear and processing procedures. Details of those procedures beyond the endpoint description are not reported in the registry record.

The endpoint is suited to comparing measured walking activity across the two treatment periods. Its meaning is specific: it is not a measure of every aspect of mobility, symptoms, or quality of life. The registry’s recorded primary comparison is between the treatment-period changes, and the available summaries should be interpreted within that scope.

7. Results Posted in the Registry

• Dalfampridine ER 10mg Bid: mean 0.60 versus 0.30 on control; difference 0.30 (95% CI 0.07 to 0.53), standardized effect d = 0.55; z-test p = 0.011.

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.

Stepcount

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Dalfampridine ER vs Baseline: mean 148.70 versus 128.00 on control; difference 20.70 (95% CI -74.34 to 115.74), standardized effect d = 0.09; z-test p = 0.669.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Dalfampridine ER vs Baseline and the control. The interval gives the range of effects that remain compatible with the data.

The registry lists one secondary outcome, Stepcount, measured in steps per day. The posted summaries give estimates in the same positive direction for dalfampridine ER versus baseline and placebo versus baseline, and the recalculated contrast is positive. However, the interval for the treatment contrast spans zero and the unadjusted p-value is 0.669. This is an uncertain secondary pattern, not a clear confirmatory result.

The secondary endpoint relates to the primary result by measuring another aspect of ambulatory activity. Peak Activity Index focuses on the fastest walking minutes, whereas Stepcount reflects the number of steps per day. A positive direction in both kinds of measure may be descriptively compatible, but it does not establish that they capture the same construct or provide independent confirmation. The secondary result is less precise and does not resolve the disagreement between the recalculated primary contrast and the sponsor’s mixed-model result.

Unadjusted secondary results generally carry less inferential weight when several outcomes or comparisons may be examined. Without a reported multiplicity plan, a p-value for a secondary measure should be treated as exploratory rather than as stand-alone confirmatory evidence. The registry record does not report whether the secondary analysis was prespecified in a hierarchy, adjusted for multiple testing, or used in a formal decision rule. It also does not report a sponsor analysis for Stepcount.

The broader pattern is therefore limited: the secondary activity measure has a positive estimated contrast but considerable uncertainty. It can add context about the range of activity measures recorded, but it should not be used to overturn or validate the primary sponsor analysis. Interpretation should retain the distinction between the endpoint-specific estimate, its uncertainty, and the unreported multiplicity strategy.

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

• Stepcount

9. Statistical Interpretation

10. Statistical Methods Explained

The registry presents a continuous primary outcome summarized by means and standard deviations. The outcome is change in Peak Activity Index, measured in strides per minute. A mean describes the average observed value in a group; a standard deviation describes how spread out individual values are around that mean. Neither quantity alone gives the uncertainty in a between-treatment comparison.

What the mean difference represents

A mean difference contrasts the average outcome in one treatment condition with the average in the comparator condition. The simple recalculation from the posted summaries gives a difference of 0.3. This is an unadjusted recalculation, not a reproduction of the registry’s mixed-model analysis. It uses the displayed summary statistics and does not incorporate unreported participant-level data or model terms.

In a crossover study, observations can be related within each participant. An analysis that uses paired observations may account for this relationship and may also model period or sequence effects. A simple contrast of treatment-level summaries cannot recover all those features. The registry’s mixed-model method is named, but its specification and the information needed to reproduce it are not reported in the registry record.

What the p-value says

A p-value describes how compatible the data are with a specified null model, under the assumptions of the analysis. It is not the probability that the null hypothesis is true, and it does not measure the size or practical importance of an effect. The simple recalculation has an unadjusted p-value of 0.011. The registry’s mixed-model analysis reports a p-value of 0.586. Because the results differ and the registry marks a discrepancy, the sponsor’s own analysis takes precedence. The p-values must not be blended or treated as interchangeable.

The term unadjusted matters because the recalculation is not presented as accounting for a broader family of outcomes or comparisons. The registry record does not report whether a multiplicity adjustment was prespecified or performed. It also does not report the model’s test specification or any adjustment variables. The posted data therefore do not establish that either p-value controls error across all outcomes or analyses.

Why crossover structure matters

General statistical context: crossover trials can gain information from comparing each participant under both conditions, because stable participant characteristics are shared across those periods. At the same time, valid interpretation can depend on treatment period, sequence, and whether an earlier treatment influences observations in a later period. The described two-week washout separates the treatment periods, but its adequacy and the original analytic handling of carryover are not reported in the registry record. No assumption about those matters should be inferred from the reported label “Mixed Models Analysis.”

The listed sample sizes differ across the two primary treatment summaries: 43 for dalfampridine ER and 42 for placebo. Since this is a crossover trial, those figures do not by themselves explain the number of participants with paired observations or identify the population included in the model. Participant flow, missing outcome handling, and the analysis population are not reported in the registry record.

What over-dispersion would mean

General statistical context: over-dispersion occurs when variability is greater than a statistical model expects. It can make standard errors too small if the model fails to account for the extra variation, leading to confidence intervals that are too narrow and p-values that appear more compelling than warranted. The primary endpoint is continuous, and the registry gives standard deviations, but it does not report an over-dispersion assessment or a model diagnostic. There is therefore no basis in the registry record to claim that over-dispersion was present or that a particular correction was used.

For the secondary Stepcount endpoint, the recalculation uses an approximate pooled standard deviation of 223.5. The record marks that standard deviation as approximate. This secondary calculation is distinct from the sponsor’s reported primary model, for which no comparable specification details are recorded.

How to read the confidence interval

A confidence interval gives a range of effect estimates compatible with the data and the assumptions used to calculate it. General statistical context: narrower intervals indicate greater precision, while wider intervals indicate greater uncertainty. The recalculated primary interval excludes zero, but it is not the interval from the sponsor’s mixed model; the registry reports no confidence interval for that model result. The secondary Stepcount interval spans zero, reflecting substantial uncertainty about the direction and size of its contrast. These intervals should be interpreted with their respective analyses, rather than as interchangeable summaries.

In short, the posted means and dispersions permit a simple comparison, while the registry’s mixed-model output is the reported sponsor analysis. The crossover structure and the discrepancy make it especially important to separate descriptive summaries, recalculated statistics, and the sponsor’s inferential result. Details needed to assess or reproduce the model are not reported in the registry record.

11. Confidence Intervals and Precision

Precision concerns how narrowly the effect is estimated, not whether the result is important in practice. A confidence interval represents a range of values compatible with the data under the calculation’s assumptions. A narrow interval conveys more precision than a wide one; an interval that spans zero includes both no difference and differences in either direction.

For the simple primary recalculation, the reported interval excludes zero. However, it belongs to the unadjusted recalculation from posted summary statistics, not to the sponsor’s mixed-model analysis. The registry reports no confidence interval for the sponsor analysis. Given the discrepancy between the two analyses, the recalculated interval should not be used as if it were the uncertainty interval for the sponsor’s model estimate.

The secondary Stepcount recalculation has an interval from -74.34 to 115.7 steps per day, which spans zero and includes estimates in either direction. That breadth indicates considerable uncertainty in the estimated secondary contrast. It does not establish equivalence or rule out potentially meaningful differences; the registry record does not define an equivalence margin or a threshold for meaningful change.

The sample sizes listed for the primary summaries are 43 and 42, but these counts alone do not determine precision in a crossover analysis. The within-participant association, model structure, missing observations, and analysis population can all affect uncertainty. Those details are not reported in the registry record. Accordingly, the sponsor’s reported p-value can be stated, but its precision cannot be fully assessed from the registry because its confidence interval is not reported.

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 sample-size table and curve are planning illustrations based on the observed effect, not a record of the trial’s original enrollment calculation. The figures are participants per arm, not total events. The stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and detection of the stated fraction of the observed effect. The original trial design assumptions are not reported in the registry record.

The 80% power column gives the illustrative number of participants per arm under which the assumed design would have an 80% chance of detecting the specified effect, if the assumptions and effect were correct. The 90% power column gives the corresponding planning number for a 90% chance. These are design concepts under a model, not guarantees about any future study. The listed calculations use effect sizes set at 100%, 75%, or 50% of the observed effect. For the primary outcome, the corresponding per-arm planning figures are 52 and 70 for planning at 100% of the observed effect; 93 and 124 at 75%; and 208 and 278 at 50%.

Smaller target effects require more participants because they are harder to distinguish from ordinary sampling variation. For this reason, the illustrations increase in size as the assumed fraction of the observed effect decreases. The figures are not observed power.

These planning calculations assume equal allocation between two arms and a normal approximation. They are not tailored to the reported crossover design in the absence of a stated within-participant correlation or other design details. They should therefore be read as general planning illustrations based on the observed contrast, not as a reconstruction of the study’s design rationale.

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, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 0.300; pooled standard deviation σ = 0.545.
2. n = 2 × (1.96 + 0.842)² × 0.545² / 0.300² = 51.8, rounded up to 52 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
delta <- 0.3                      # observed difference in means
sigma <- 0.544962693539106                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^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 (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(1356940)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 52 (80% power), 70 (90% power)
 75% of observed effect: n per arm = 93 (80% power), 124 (90% power)
 50% of observed effect: n per arm = 208 (80% power), 278 (90% power)
power.t.test: 52.8 
Simulated power at n = 52 per arm: 0.789 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-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 reports a mixed-model analysis for the primary outcome. It gives a mean difference in final values of 0.586 and a p-value of 0.586. A confidence interval for that result is not reported in the registry record.

The simple recalculation from the posted treatment summaries gives a mean difference of 0.3, an unadjusted p-value of 0.011, and a confidence interval that excludes zero. This calculation is based on posted summary statistics and is not the same as the sponsor’s mixed-model analysis. The discrepancy flag is true, so the sponsor’s own analysis takes precedence.

The difference cannot be reconciled from the registry entry alone. The model specification, analysis population, handling of within-participant observations, and treatment of period or sequence are not reported in the registry record. The recalculation can help readers see that a simple contrast of the displayed summaries does not reproduce the sponsor result, but it should not replace that reported result. The sponsor’s estimate and p-value are the primary inferential figures to cite, while the recalculation should be clearly labelled as an unadjusted check.

15. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when several outcomes, time points, comparisons, or analyses are considered. The more opportunities there are to identify a result, the greater the chance that at least one result may appear notable by chance if each is assessed without adjustment. Statistical strategies can address this, for example by prespecifying a primary outcome or adjusting inference across a defined family. General statistical context does not establish which approach was used in this trial.

The registry identifies Peak Activity Index as the primary outcome and Stepcount as a secondary outcome. It reports one primary mixed-model analysis and does not list a sponsor analysis for Stepcount. Whether the trial used a formal testing hierarchy, multiplicity adjustment, or other control of false-positive risk is not reported in the registry record. The primary outcome’s status does not by itself reveal how the study’s full analysis plan handled secondary measures or additional comparisons.

Important analysis details are also absent. The registry does not report the original statistical analysis plan, model formula, covariates, assumptions, treatment of period and sequence, handling of carryover, or exact analysis population. Missing-data methods, reasons for the different outcome counts, adherence, and participant flow are not reported in the registry record. It is also not reported whether there were interim analyses or any rules for stopping or changing the study.

These omissions matter because a crossover analysis can depend on the relationship between a participant’s observations across treatment periods. A model that accounts for that structure may produce different estimates and uncertainty from a simple comparison of group summaries. Without the specification and participant-level data, the sponsor result cannot be reproduced or independently checked in detail.

The registered sample-size illustrations use a two-sided significance level of 0.05 and equal allocation for planning purposes, but these are not identified as the trial’s original design assumptions. The trial’s own sample-size justification is not reported in the registry record. Consequently, readers can describe the posted primary and secondary statistics, but cannot establish from the registry whether the full analysis plan adequately addressed multiplicity, missing data, or the crossover features.

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 0% reporting threshold.

Most frequent non-serious adverse event terms

The adverse-event figures list zero serious adverse events among 43 participants in the dalfampridine ER group and zero among 42 in the placebo group. These are the counts recorded for the groups and should be read alongside the number at risk stated for each group.

The record also lists two other adverse events in the dalfampridine ER group and zero in the placebo group. These are reported separately from serious adverse events. The registry does not provide serious-event terms, and deaths are not reported in the registry record. It also does not describe event relatedness, severity grading beyond the serious/non-serious distinction, duration, or whether individuals could contribute more than one event.

Zero recorded serious events in these groups is a descriptive finding for this trial record. It does not establish that serious events cannot occur, and the figures alone do not support a comparative safety conclusion. The trial’s enrollment and the limited event counts constrain what can be learned about uncommon harms. These counts should not be interpreted as medical advice or as a complete account of safety information beyond the registry entry.

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

The posted data describe a randomized, triple-masked crossover comparison of dalfampridine ER and placebo in people with multiple sclerosis, with Peak Activity Index as the primary outcome. The simple recalculation from the posted summaries gives a mean difference of 0.3 strides per minute and an unadjusted p-value of 0.011. The sponsor’s mixed-model analysis instead reports a mean difference of 0.586 and a p-value of 0.586, with no confidence interval reported. Because the discrepancy flag is true, the sponsor’s own analysis takes precedence.

That distinction means the simple recalculation should not be presented as the trial’s definitive result. It is a summary-statistic-based check, and it differs from the registry’s reported model analysis. The missing model details prevent a full explanation of the disagreement. The registry record also does not report the original analysis plan, the analysis population, missing-data methods, or how crossover period and sequence features were handled.

The result concerns a specific accelerometer-derived measure of the fastest walking minutes, averaged over a week, and change from baseline to four weeks on intervention. It does not by itself answer questions about every kind of mobility, daily function, symptoms, or quality of life. The secondary Stepcount estimate is uncertain and should be treated as supportive context at most, particularly because multiplicity handling is not reported.

The record reports no serious adverse events in either treatment group and lists two other adverse events in the dalfampridine ER group and none in the placebo group. These counts are descriptive and do not establish broader safety conclusions. In sum, the registry supplies outcome summaries and a sponsor model result, but incomplete analytic details and disagreement between the two primary calculations limit how strongly the posted statistics can be interpreted.

18. Why This Trial Matters Statistically

This trial is statistically notable because the design is crossover, while the most visible recalculation is based on posted treatment-level summaries. In a crossover study, each participant may contribute information under both treatment conditions. That structure can affect the estimate and its precision, so a simple contrast of summary means need not reproduce an analysis that models participant-level observations.

The primary results make that issue concrete: the unadjusted recalculation and the registry’s mixed-model analysis give different estimates and p-values. The registry marks a discrepancy, and the sponsor’s own analysis takes precedence. This is a reminder that numerical agreement cannot be assumed between a calculation based on summary statistics and a model that may use different data or assumptions. The registry does not report enough detail to determine the source of the difference.

The trial also illustrates why statistical interpretation requires more than reading a p-value. The effect estimate, its uncertainty, the design, the analysis population, and the prespecified analysis strategy all matter. Here, the sponsor result has no reported confidence interval, while key model and missing-data details are absent. The secondary result is also uncertain, and its relationship to any multiplicity plan is not reported.

Finally, the sample-size figures are planning illustrations based on an observed effect, not evidence about the original design or the power achieved in the trial. Their interpretation depends on stated assumptions that do not explicitly reflect all features of the crossover design. Together, these features make the registry useful for examining how design and analysis choices shape the interpretation of clinical trial statistics, while also showing the limits of a record with incomplete methods detail.

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.

Several limitations are specific to interpreting this record. First, the sponsor’s mixed-model result and the unadjusted recalculation from the posted summaries differ. The sponsor analysis takes precedence, but its confidence interval and model specification are not reported. The available record therefore does not allow a detailed reconciliation or independent reproduction.

Second, the crossover design raises analytic questions about paired observations, period, sequence, and possible carryover. The treatment sequences and two-week washout are described, but the registry does not report how the sponsor’s model handled these features or whether carryover was assessed. It would be inappropriate to assume that the washout or a particular model fully resolves those issues.

Third, the primary outcome summaries list different counts for the two treatments. The registry does not explain the difference, report participant flow, identify the number with complete paired data, or describe missing-data handling. The analysis population and adherence are not reported in the registry record, limiting assessment of the estimates’ representativeness.

Fourth, the secondary Stepcount result is imprecise and is not accompanied by a sponsor analysis in the record. Multiplicity procedures and the full prespecified outcome hierarchy are not reported. The sample-size illustrations use planning assumptions that are stated, but the original trial’s sample-size justification and design assumptions are not reported.

Finally, adverse-event reporting is limited to aggregate counts for serious and other events. Event terms, relatedness, deaths, and fuller safety details are not reported in the registry record. These limitations constrain inference about both efficacy-related outcomes and safety; they do not, on their own, establish that any particular bias or analytic problem occurred.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: A Placebo Controlled Trial of Dalfampridine ER for Ambulatory Activity in People With Multiple Sclerosis — NCT01356940.
• Registry record last updated 2018-10-31; status last verified 2018-10.
• Results first posted 2015-04-09.
• 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

The registry describes a completed Phase 4 randomized, triple-masked, placebo-controlled crossover trial in people with multiple sclerosis, with 43 participants enrolled. Treatment sequences comprised four weeks of dalfampridine ER 10mg bid and four weeks of placebo, separated by a two-week washout.

The primary endpoint was change in Peak Activity Index, measured in strides per minute. The posted summaries yield a simple unadjusted mean difference of 0.3, while the registry’s mixed-model analysis reports a mean difference of 0.586 and p=0.586. Because the record flags a discrepancy, the sponsor’s analysis takes precedence. The registry also lists Stepcount as a secondary outcome, with an uncertain recalculated contrast.

Important details—including the original analysis plan, model specification, missing-data methods, multiplicity strategy, and analysis population—are not reported in the registry record. Serious adverse event counts are zero in both listed groups; two other adverse events are listed for dalfampridine ER and none for placebo.