Study to Test Rizatriptan in the Early Treatment of Acute Migraine (0462-081): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study to Test Rizatriptan in the Early Treatment of Acute Migraine (0462-081) (NCT00516737), a randomized phase 3 study. The primary outcome is Number of Participants Who Are Pain Free at 2 Hours Post-Dose.

2. Clinical Question

The trial asked whether participants assigned to rizatriptan 10 mg ODT differed from those assigned to placebo in the number recorded as pain free 2 hours after dosing for an acute migraine attack. The primary outcome was a count of participants meeting a diary-based definition, rather than a measure of how much pain changed on average.

The posted primary results count 61 participants in the rizatriptan arm and 27 in the placebo arm as pain free at the endpoint. The comparison is expressed as an unadjusted risk difference with a confidence interval and an unadjusted p-value. These summaries describe the recorded outcomes in the endpoint population; they do not by themselves establish how the result would apply to people outside the trial or to other treatment settings.

3. Trial Design

The registry identifies this as a Phase 3, randomized, double-blind, parallel-group, placebo-controlled trial. Its official title describes a multicenter factorial design. The record lists rizatriptan benzoate and placebo as the interventions, and the arm descriptions identify rizatriptan 10 mg ODT and a matching placebo comparator. Details about the factorial factors are not reported in the registry record.

The trial enrolled 207 participants. The primary outcome results use the Full Analysis Set, defined as randomized participants with at least one assessment within 2 hours post-dose after the baseline assessment. The reported primary endpoint denominators are 92.0 for rizatriptan and 96.0 for placebo. The registry does not explain in the posted results why those denominators differ from overall enrollment.

The study status is completed. The record gives a start date of 2007-10-03 and a primary completion date of 2008-04-08. Organon and Co is listed as the sponsor. The registry record identifies migraine as the condition and describes the purpose as testing rizatriptan benzoate for early treatment of an acute migraine attack.

Random allocation and double masking are important features for interpreting a comparison: randomization is intended to reduce systematic differences between assigned groups, while masking is intended to limit the influence of treatment knowledge on participants or study personnel. Those design features do not resolve questions about implementation, adherence, outcome handling, or analysis choices; details on those matters are not reported in the registry record.

4. Participant Flow and Accounting

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

Before assignment: Participants were assessed, using the protocol inclusion and exclusion criteria, at Visit 1, and if eligible were randomized at that same visit.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Full Analysis Set (FAS): The FAS population includes all randomized participants who have at least one assessment within 2 hours post-dose (i.e., after baseline assessment).

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 Number of Participants Who Are Pain Free at 2 Hours Post-Dose, measured over 2 hours post-dose.

The primary endpoint is the number of participants who were pain free 2 hours after dosing. Participants rated pain severity in a paper diary using a scale from 0, no pain, to 3, severe pain, with 1 indicating mild pain and 2 indicating moderate pain. For this endpoint, pain free means a rating of 0 at the specified assessment. The outcome is therefore a participant count based on a single stated threshold, not a mean pain score or a measure of change from baseline.

The endpoint population is the Full Analysis Set, which includes all randomized participants who had at least one assessment within 2 hours after dosing, following baseline assessment. The reported arm counts are 61 of 92.0 for rizatriptan and 27 of 96.0 for placebo. The registry records the outcome timeframe as 2 hours post-dose.

In general, a binary endpoint can make a result easy to interpret because each participant either meets the specified outcome definition or does not. A pain-free assessment is a direct report of symptom status at a defined time. It does not capture every aspect of the migraine attack, the duration of relief, or participants’ experience at other times. The registry lists sustained pain freedom at 24 hours and other symptom or functional outcomes as secondary measures, but those are distinct questions rather than extensions of the primary endpoint’s definition.

7. Results Posted in the Registry

• Rizatriptan 10 mg ODT: 66.3% (61/92) versus 28.1% (27/96) on control; risk difference 38.2 percentage points (95% CI 25.0 to 51.4), risk ratio 2.36 (1.66–3.35); unadjusted two-proportion z-test p = <0.001.

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.

Number of Participants With 24-Hour Sustained Pain Freedom

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Rizatriptan 10 mg ODT: 52.2% (48/92) versus 17.7% (17/96) on control; risk difference 34.5 percentage points (95% CI 21.7 to 47.2), risk ratio 2.95 (1.83–4.73); unadjusted two-proportion z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the proportion with the event is statistically higher for Rizatriptan 10 mg ODT than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Number of Participants With no Rescue Use up to 24 Hours Post-Dose

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Rizatriptan 10 mg ODT: 66.3% (61/92) versus 33.3% (32/96) on control; risk difference 33.0 percentage points (95% CI 19.5 to 46.5), risk ratio 1.99 (1.45–2.73); unadjusted two-proportion z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the proportion with the event is statistically higher for Rizatriptan 10 mg ODT than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Number of Participants With Absence of Photophobia at 2 Hours Post-dose

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Rizatriptan 10 mg ODT: 75.0% (69/92) versus 44.8% (43/96) on control; risk difference 30.2 percentage points (95% CI 16.9 to 43.5), risk ratio 1.67 (1.30–2.15); unadjusted two-proportion z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the proportion with the event is statistically higher for Rizatriptan 10 mg ODT than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The registry lists six secondary outcome measures covering sustained pain freedom through 24 hours, rescue use, photophobia, phonophobia, nausea, and functional disability. Numerical arm counts and recalculated comparisons are available in the posted results for sustained pain freedom, no rescue use, and absence of photophobia. Numerical results for absence of phonophobia, absence of nausea, and absence of functional disability are not reported in the registry record.

Across the secondary outcomes with numerical comparisons, the event counts are higher in the rizatriptan arm than in the placebo arm, and the recalculated risk differences are positive. This direction is consistent with the primary endpoint comparison, but the secondary measures do not simply replicate the primary question: they assess persistence of pain freedom, use of rescue medication, or other symptoms. The posted results therefore describe a broader set of outcome dimensions, but do not establish that every listed secondary outcome had the same pattern.

The displayed secondary p-values are unadjusted. In general, when several outcomes are tested, considering each p-value in isolation can overstate the strength of evidence because multiple opportunities for a low p-value exist. The registry does not report a multiplicity adjustment, a testing hierarchy, or which secondary outcomes were intended to be confirmatory. These findings are consequently best treated as supportive descriptive comparisons rather than independent confirmation of the primary result. Their interpretation also depends on endpoint definitions and missing-data handling, which are not fully described in the registry record.

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

• Number of Participants With 24-Hour Sustained Pain Freedom
• Number of Participants With no Rescue Use up to 24 Hours Post-Dose
• Number of Participants With Absence of Photophobia at 2 Hours Post-dose
• Number of Participants With Absence of Phonophobia at 2 Hours Post-dose
• Number of Participants With Absence of Nausea at 2 Hours Post-dose
• Number of Participants With Absence of Functional Disability at 2 Hours Post-Dose

9. Statistical Interpretation

10. Statistical Methods Explained

The primary comparison is binary: each participant either met the definition of pain free at 2 hours post-dose or did not. The registry reports the number meeting the definition in each arm, the arm denominators, and a risk difference. For a binary outcome, the risk or event proportion is the share of participants in an arm who experienced the defined event. The risk difference subtracts the comparator arm’s proportion from the intervention arm’s proportion. Here, the posted estimate is 0.382 for rizatriptan compared with placebo.

What does the risk difference describe?

The risk difference is an absolute measure. Its sign gives the direction of the comparison under the stated ordering, and its magnitude expresses how far apart the arm proportions are on the probability scale. It is distinct from a relative measure, which compares one arm’s event rate with the other arm’s rate. The posted comparison also includes risk-ratio and odds-ratio summaries, but those answer different mathematical questions and can be less directly read as an absolute change. None of these measures alone accounts for factors not represented in the posted calculation.

What does “unadjusted” mean?

The comparison estimates and p-values are simple unadjusted recalculations from the posted summary counts. An unadjusted comparison uses the arm-level outcome information without an additional adjustment for covariates or other modeling terms. In general, adjustment can be used to account for prespecified prognostic variables or design features, but whether any such adjusted analysis was planned or performed is not reported in the registry record. The record lists no reported analyses for the primary result. The p-value is explicitly unadjusted and should not be read as a reported result from a more detailed model.

How should the p-value be understood?

In general, a p-value measures how unusual data at least as discrepant as those observed would be under a specified null model, assuming the model’s conditions hold. A small p-value indicates incompatibility between the observed data and that null model; it is not a measure of the probability that a treatment effect is real, nor is it a measure of the effect’s clinical importance. The posted primary p-value is <0.001. The registry does not report whether a different inferential procedure, covariate adjustment, or multiplicity strategy was used in the trial’s original analysis.

Why does randomization matter?

In general, random allocation aims to make treatment groups comparable with respect to measured and unmeasured characteristics, apart from chance differences. Double masking is intended to reduce the influence of knowledge of assigned treatment on behavior, assessment, and reporting. The registry identifies the design as randomized and double-blind, but the details of sequence generation, concealment, masking procedures, and any departures from assigned treatment are not reported in the registry record. Design labels are informative but do not replace those operational details.

What is the role of the endpoint population?

The primary result uses the Full Analysis Set, defined as randomized participants with at least one assessment within 2 hours post-dose after baseline. Thus, the denominator is tied to availability of a post-baseline assessment as well as randomization. In general, excluding participants without an endpoint assessment can affect interpretation if assessment availability is related to treatment assignment or outcome. The registry does not describe how missing outcome values were handled, whether participants were imputed as responders or nonresponders, or whether sensitivity analyses were conducted. No specific missing-data method should be inferred.

What do the secondary analyses add?

The registry lists outcomes involving sustained pain freedom, rescue use, photophobia, phonophobia, nausea, and functional disability. The posted numerical comparisons for the secondary outcomes available in the results use the same type of unadjusted risk-difference summary. These outcomes address related but distinct aspects of an acute attack. In general, testing multiple outcomes raises a multiplicity issue: the chance of at least one apparently notable result can increase when many hypotheses are examined. The registry does not report a correction procedure, hierarchy, or prespecified strategy for interpreting those outcomes. Consequently, nominal unadjusted p-values for secondary outcomes should not be treated as if they were adjusted confirmatory tests.

The methods information is therefore enough to describe the basic endpoint definition, analysis population, arm counts, and recalculated unadjusted comparison. It is not enough to reconstruct the full statistical analysis plan or verify how every analysis decision was made. Original sample-size assumptions, interim analyses, missing-data procedures, and model specifications are not reported in the registry record.

11. Confidence Intervals and Precision

The primary risk-difference estimate is 0.382, and its 95% confidence interval is 0.250 to 0.514. The interval gives a range of values that are compatible with the observed data under the calculation’s statistical assumptions. It conveys more information than a p-value alone: it shows both the estimated direction and the uncertainty around the estimated size of the absolute difference.

The interval does not include zero, which corresponds to no risk difference. That is consistent with the posted unadjusted p-value of <0.001. The interval is nevertheless not a guarantee that the true difference lies within its endpoints, nor does it incorporate uncertainty about all aspects of trial conduct, endpoint measurement, missing data, or analysis choices. It quantifies sampling uncertainty under the calculation used.

Precision should be considered alongside the endpoint and population. The result estimates the difference in the proportion recorded as pain free at 2 hours among participants in the stated Full Analysis Set. It does not directly quantify uncertainty for the 24-hour outcomes or for the other secondary measures, and it does not describe individual responses. The primary arm denominators are 92.0 and 96.0; the interval reflects the information in the posted primary counts and those denominators.

In general, a wider confidence interval indicates less precision, while a narrower interval indicates more precision, given the same estimand and method. Even an interval that excludes no difference can leave meaningful uncertainty about the size of the effect. Interpretation should therefore consider the full range from 0.250 to 0.514 rather than relying only on whether the interval crosses zero. The registry record does not provide a prespecified threshold for clinical importance, so the interval cannot be classified against such a threshold from the posted information.

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 figures are expressed as participants per arm, not as total events. They are illustrations based on the observed effect, not a report of the trial’s original sample-size calculation. The stated planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Each scenario uses the stated fraction of the observed effect as the effect to detect. The original design assumptions for this trial are not reported in the registry record.

The 80% power column gives the number of participants per arm that the planning calculation estimates would be needed for an 80% chance of detecting the specified effect under those assumptions, if that effect were present and the assumptions held. The 90% power column gives the corresponding planning number for a 90% chance. Power is a property of a planned design under assumed conditions; it does not describe the probability that the observed result is true.

The rows illustrate planning for 100%, 75%, and 50% of the observed effect. As the target effect becomes smaller, the calculation requires more participants per arm to retain the same target power. For example, for the primary comparison, planning for 100% of the observed effect gives 26 participants per arm for 80% power and 34 for 90% power; planning for 50% gives 100 and 134 participants per arm, respectively. These values are planning illustrations and are not observed power.

The calculation uses the observed effect as its starting point, so it should not be mistaken for a record of what investigators assumed before enrollment. The registry does not report the original sample-size justification, its assumed event rates, or whether other design considerations affected the planned enrollment. The planning figures should be read as conditional illustrations under the listed assumptions, not as evidence that a particular sample size is adequate for every endpoint or analysis.

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 = 0.281; treatment proportion p₁ = 0.663; average p̄ = 0.472.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.7060 = 1.3838.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.6524 = 0.5490.
4. n = (1.3838 + 0.5490)² / (0.3818)² = 25.6, rounded up to 26 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 <- 0.28125                          # control proportion
p1 <- 0.66304347826087                          # 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(516737)
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 = 26 (80% power), 34 (90% power)
 75% of observed effect: n per arm = 46 (80% power), 61 (90% power)
 50% of observed effect: n per arm = 100 (80% power), 134 (90% power)
power.prop.test: 25.6 
Simulated power at n = 26 per arm: 0.789 (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. Multiplicity, Missing Data and Analysis Populations

The registry identifies a primary outcome and six secondary outcomes, but does not report a statistical plan for controlling multiplicity. In general, multiplicity arises when more than one outcome or hypothesis is tested: without an appropriate strategy, the chance of at least one apparently strong result can increase. Common strategies include defining a hierarchy or adjusting the testing threshold, but whether any strategy was specified or used in this trial is not reported in the registry record. The posted secondary comparisons are unadjusted and should be read with that limitation in mind.

The primary analysis population is defined as the Full Analysis Set: all randomized participants with at least one assessment within 2 hours post-dose after baseline. The endpoint denominators are 92.0 in the rizatriptan arm and 96.0 in the placebo arm. The registry does not report the number of randomized participants without a qualifying assessment, why any assessments were unavailable, or how missing endpoint values were treated. It also does not describe sensitivity analyses examining alternative assumptions about missing data.

The record does not report whether the primary analysis was adjusted for baseline characteristics, whether an interim analysis was planned or conducted, or whether the reported comparisons follow a prespecified analysis plan. Reported analyses are not listed for the posted secondary comparisons. These omissions limit the ability to distinguish planned confirmatory analyses from exploratory or descriptive comparisons. They also prevent reconstruction of the full inferential procedure from the registry record alone.

In general, missing outcome data can affect a comparison if the chance of having an assessment is related to assigned group or the outcome itself. The stated Full Analysis Set definition clarifies who could contribute to the primary result, but it does not explain the consequences of absent assessments. No particular missing-data mechanism or method should be assumed from the posted information.

15. 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 safety figures report zero participants with serious adverse events in the rizatriptan 10 mg ODT group, among 92 at risk, and zero in the placebo group, among 96 at risk. The registry lists no serious adverse-event terms. This means the posted serious-event counts are zero in both groups; it does not establish that serious events are impossible or that the treatments have equivalent safety.

The record also reports 6 participants with other adverse events among 92 at risk in the rizatriptan group and 3 among 96 at risk in the placebo group. These counts are distinct from the serious adverse-event counts. The registry does not provide the event terms or further detail about severity, timing, attribution, or handling of adverse events in the posted information. Deaths are not reported in the registry record.

Safety counts are descriptive and should be read in light of the trial’s enrollment and the available reporting detail. They do not provide a complete characterization of potential harms, and the posted figures alone do not support a broad conclusion about comparative safety.

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

The primary result describes an observed difference in the number of participants who met a specific diary-based definition of pain freedom 2 hours after dosing. The recalculated unadjusted risk difference is 0.382, with a 95% confidence interval from 0.250 to 0.514 and an unadjusted p-value of <0.001. The result is a comparison of the randomized arms for this outcome and timepoint, in the stated Full Analysis Set.

It does not mean that every participant in the rizatriptan arm was pain free, or that participants who did not meet the endpoint had no change in pain. The binary endpoint records whether a participant gave a rating of 0 at the specified assessment. It does not describe intermediate changes in pain severity, the timing of relief before the assessment, or the experience after that assessment.

The primary finding also does not answer all questions about sustained response, rescue medication, associated symptoms, or functional disability. Those outcomes are listed as secondary measures and are separate from the primary endpoint. Numerical results are not reported for every listed secondary measure. The registry record also does not provide enough statistical-plan detail to determine whether secondary tests were adjusted for multiplicity or how missing outcomes were handled.

In general, statistical evidence about a group difference should not be confused with a judgment about clinical importance. The registry does not report a threshold for what would count as a clinically important difference. Nor do the posted results establish how well the findings apply to people or settings not represented by the trial. Interpretation should stay tied to the trial’s population, comparison, outcome definition, and assessment time.

The safety information is limited to the posted counts, with no serious adverse events recorded in either arm and other adverse events recorded in both. The available safety summary does not establish absence of risk. Taken together, the posted results describe a clear statistical contrast on the defined primary endpoint, while leaving broader questions about clinical importance, generalizability, missing information, and other outcomes unresolved.

17. Why This Trial Matters Statistically

This trial illustrates how a binary clinical endpoint turns participant-level symptom assessments into a group comparison. The primary measure is not a mean score: it counts participants whose diary rating met the explicit pain-free threshold at a prespecified time. The resulting risk difference is an absolute measure, which complements relative measures and makes the comparison’s scale clear.

It also shows why the endpoint population matters. The trial enrolled 207 participants, but the primary outcome is defined for randomized participants with at least one post-baseline assessment within 2 hours. The arm denominators reported for the primary result are 92.0 and 96.0. A reader needs both the outcome definition and the analysis-population definition to understand what the result estimates; the enrollment total alone does not describe the endpoint denominator.

The confidence interval adds information that a significance test cannot provide by itself. It communicates uncertainty about the size of the unadjusted risk difference, while the p-value addresses compatibility with a null comparison under statistical assumptions. Neither statistic supplies a threshold for clinical importance, which is not reported in the registry record.

The secondary outcomes also illustrate the importance of multiplicity. A set of related outcomes can help describe different aspects of an acute attack, but unadjusted tests across multiple outcomes should not automatically be treated as separate confirmatory evidence. Finally, the planning illustrations demonstrate how sample-size requirements depend on the effect targeted and the stated design assumptions. They are not the trial’s original justification and are not a retrospective measure of power.

18. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The posted statistical detail is limited. The registry does not report the original sample-size justification, a full analysis plan, adjustment for baseline covariates, interim analyses, or a multiplicity strategy. The primary and available secondary comparisons are unadjusted recalculations from posted summary counts. These registry entries limit reconstruction of the investigators’ original inferential approach.

The primary outcome is a diary rating at 2 hours post-dose. It captures pain-free status at that specific assessment, not the course of pain over time or every dimension of an attack. The registry lists other outcomes, but numerical results are not reported for all six secondary measures. The record also does not describe how missing assessments or missing diary values were handled, beyond defining the Full Analysis Set.

The overall enrollment is 207, while the primary endpoint denominators are 92.0 and 96.0. The registry does not explain the difference between enrollment and the endpoint population counts. The available description does not report detailed participant characteristics, adherence, protocol deviations, or the procedures used to implement allocation and masking. The official title describes a factorial design, but the factors and their analysis are not reported in the registry record.

Safety reporting is also limited to the posted participant counts. Serious adverse-event counts are zero in both arms, while further terms and details for other adverse events are not given. Deaths are not reported in the registry record. These limitations mean that the summaries can describe the reported comparisons, but cannot answer every question about trial conduct, response patterns, or safety.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Study to Test Rizatriptan in the Early Treatment of Acute Migraine (0462-081) — NCT00516737.
• Registry record last updated 2024-04-22; status last verified 2022-02.
• Results first posted 2009-04-14.
• 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.

22. Record Summary

This completed Phase 3 randomized, double-blind, parallel-group, placebo-controlled trial evaluated rizatriptan 10 mg ODT for early treatment of an acute migraine attack. The registry lists Organon and Co as sponsor, 207 participants enrolled, a start date of 2007-10-03, and a primary completion date of 2008-04-08.

The primary endpoint was the number of participants rated pain free 2 hours post-dose, based on a paper-diary rating of 0. In the Full Analysis Set, the reported counts were 61 of 92.0 for rizatriptan and 27 of 96.0 for placebo. The unadjusted recalculated risk difference was 0.382, with a 95% confidence interval from 0.250 to 0.514 and p < 0.001. The registry lists six secondary outcomes, while numerical results are not reported for every listed measure.

Details of the original sample-size justification, multiplicity strategy, missing-data handling, and full statistical analysis plan are not reported in the registry record.