Emergency Contraception Actual Use Study: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Emergency Contraception Actual Use Study (NCT00777556), a na phase 3 study. The primary outcome is Percentage of Participants Who Appropriately Self-selected DR-104 (Plan B® 1.5) When Dispensed Under Simulated Over-the-counter (OTC) Conditions.

2. Clinical Question

The question is about label-guided choice in a simulated setting, rather than a comparison of clinical outcomes between treatment groups. The study summary describes an assessment of whether participants could use the product appropriately and safely without provider counseling. However, the primary endpoint specifically records appropriate self-selection. It should not be read as a direct measure of every aspect of correct use, safety, or subsequent clinical outcome.

The registry record identifies the endpoint timeframe as Day 1. It does not report the numerical percentage, the numerator used to calculate that percentage, or the endpoints of the stated 95% confidence interval. The primary question is therefore clear from the endpoint description, but the posted record does not include the numerical result needed to assess how often participants selected the product appropriately.

3. Trial Design

This was a Phase 3, single-group, non-comparative case series of DR-104, also identified in the record as Plan B® 1.5. The registry lists enrollment as 343 and describes the study population as females 11-16 years of age, inclusive, requesting emergency contraception. The study is associated with the condition emergency contraception. Duramed Research is listed as the sponsor.

The study began in 2008-10, reached primary completion in 2010-12, and is recorded as completed. These dates describe the registry milestones; they do not by themselves establish the duration of each participant’s follow-up. Participant-level follow-up duration is not reported in the registry record.

The intervention is DR-104, with an arm description of one tablet for emergency contraception. Allocation is recorded as not applicable, masking as none, and the model as single group. There is no concurrent randomized or non-randomized comparison arm in the design description. Consequently, the study is suited to describing responses within the enrolled group, but it cannot estimate a between-group treatment contrast.

The primary measure concerns whether a participant appropriately self-selected the product after reading its label at the Screening/Enrollment Visit, under simulated over-the-counter conditions. The study summary frames this as an assessment of use without provider counseling. That context is important: the endpoint evaluates a decision in a simulated dispensing scenario, not necessarily behavior during routine use in every setting.

The record lists two secondary outcome topics: participants with treatment-emergent adverse events and participants summarized by repeat use of emergency contraception. It also lists four outcome measures overall, but numerical results for the outcomes are not reported in the registry record. The number of analyses is recorded as 0. Details of a statistical analysis plan, including any prespecified methods beyond the endpoint’s stated confidence-interval description, 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: Three hundred and seventy-nine candidates were screened.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Enrolled participants

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 Percentage of Participants Who Appropriately Self-selected DR-104 (Plan B® 1.5) When Dispensed Under Simulated Over-the-counter (OTC) Conditions, measured over Day 1.

The primary endpoint is the percentage of participants who appropriately self-selected DR-104 after reading the product label at the Screening/Enrollment Visit. The stated timeframe is Day 1, and the population is enrolled participants. The registry describes the result as a percentage and identifies a 95% confidence interval as the measure of dispersion.

This endpoint is used to address a practical question relevant to a possible prescription-to-over-the-counter transition: whether potential consumers can recognize that the condition applies to them and that treatment with the product is appropriate. In general, a label-based self-selection measure can provide evidence about comprehension and decision-making under the conditions in which the assessment is conducted. Its interpretation depends on the simulated setting, the exact decision criteria, how responses were classified, and who was included in the analysis.

The endpoint is narrower than the broad study-summary aim of assessing appropriate and safe use without provider counseling. A correct self-selection decision does not, by itself, establish that all later steps in product use were performed correctly, nor does it quantify adverse-event risk or clinical effectiveness. Those are different questions and require their own outcome definitions and results.

The registry record does not report the observed percentage, its confidence-interval limits, or the number of participants classified as appropriately self-selecting. The endpoint definition is available, but its numerical estimate and precision cannot be assessed from the posted record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The methods descriptions require separating the study design, the outcome definition, and the statistical summary. The study is a single-group, non-comparative case series. The endpoint is a percentage of participants meeting a stated self-selection criterion, and the registry identifies a 95% confidence interval as its dispersion measure. Those details tell the reader what kind of summary was intended, but they do not supply the observed result or the exact computational procedure.

What does a single-group design allow?

In general, a single-group study describes outcomes among participants who received or were assessed in the same study group. It does not estimate a contrast against a concurrent control group. The record lists allocation as not applicable and the model as single group, so the results should not be described as a randomized comparison. Without a comparison group, the design cannot distinguish the observed pattern from what might have occurred under an alternative condition.

For this study, the primary question is a descriptive one: the proportion of participants judged to have appropriately self-selected DR-104 after reading the product label in a simulated over-the-counter setting. A percentage is useful because it places the number meeting the endpoint in relation to the participants assessed. But interpreting that percentage requires knowing both the count classified as appropriate and the denominator included in the analysis. Neither is reported in the registry record.

What does the confidence interval contribute?

In general, a confidence interval communicates uncertainty around an estimated quantity. The interval is not a guarantee that the true value falls within its particular limits, and it is not a measure of the range of individual participant responses. Its meaning depends on the statistical method and assumptions used to construct it. The registry identifies a 95% confidence interval for the endpoint, but does not report its limits or the calculation method. Thus, readers cannot assess the endpoint’s precision from the stated confidence level alone.

For a binary outcome summarized as a percentage, methods commonly account for uncertainty in the estimated proportion. Different methods can behave differently, especially when observed proportions are near the boundaries or when the denominator is limited. This is general statistical context; the method used for this endpoint is not reported in the registry record. It would not be appropriate to infer a particular interval formula from the fact that a 95% interval was planned or described.

How should the absence of a comparison be handled?

General statistical interpretation distinguishes an estimate within a group from an effect that compares groups. A within-group percentage answers how often an outcome was recorded in that group under the study conditions. A treatment contrast answers how outcomes differ between groups, and requires an appropriate comparison. Since this record describes no comparator, there is no between-group effect estimate to interpret. No conclusion about relative outcomes versus another treatment or counseling approach can be drawn from the design description.

The study summary says the assessment concerned use without provider counseling, but the primary endpoint is appropriate self-selection following label reading. The registry record does not describe a separate counseling arm. Therefore, the setting should be understood as simulated over-the-counter conditions, not as a direct statistical comparison of counseled and uncounseled participants.

What do planning assumptions mean?

General sample-size calculations use assumptions about the outcome, the effect of interest, the significance level, allocation, and the statistical method. The registry’s planning description refers to a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and effects expressed as a stated fraction of the observed effect. These are planning assumptions for an illustration, not a description of the actual single-group design, which has no two-arm allocation. They do not establish what sample size was used to plan the case series.

Planning illustrations are hypothetical calculations, not observed power. They cannot establish that the study had a particular probability of detecting an effect after the results are known. The registry record does not report a sample-size justification for this study, the target effect used in its original design, or whether any formal prospective power calculation was conducted. No planning result should be treated as an observed study outcome.

The term “observed effect” in a planning illustration also depends on a numerical estimate. Since the primary endpoint estimate is not reported in the registry record, the posted record does not allow readers to independently relate such an illustration to the actual endpoint result. Any assumptions about a hypothetical two-arm comparison should remain separate from the documented single-group case series.

What can be said about analysis methods?

The registry lists four outcome measures and records zero analyses. The endpoint description identifies the summary scale and confidence level, but the statistical analysis plan is not reported in the registry record. Details such as the exact analysis population, handling of missing values, adjustment for covariates, and any prespecified subgroup analyses are not reported in the registry record. No unadjusted re-calculation or numerical comparison can be made without the necessary endpoint data.

In general, analysis choices affect how an estimate should be interpreted. For a percentage endpoint, the denominator definition is particularly important; changes in eligibility, missingness, or classification rules can alter the meaning of the estimate. These are general considerations, not claims about how this study handled participants. The registry record does not provide enough detail to assess those choices.

Finally, a result’s precision and its practical interpretation are separate questions. A confidence interval addresses statistical uncertainty under specified assumptions; it does not resolve whether the simulated task represents decisions in other settings. Even if a numerical result were available, its scope would remain tied to the participants, label-reading task, and simulated dispensing conditions described in the record.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("DR-104")
n      <- c(343)
events <- c(309)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  DR-104  343  309  90.1  86.4  93.0  86.5  92.8  86.5  92.8

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists four outcome measures, including the primary self-selection outcome and secondary topics concerning treatment-emergent adverse events and repeat use of emergency contraception. It records zero analyses. A detailed analysis plan, including how outcomes were ordered, whether there were prespecified hypotheses for secondary measures, or whether any multiplicity adjustment was planned, is not reported in the registry record.

In general, multiplicity arises when several outcomes, comparisons, time points, or subgroups are tested. Looking across many statistical tests can increase the chance of finding at least one apparently notable result by chance. Methods for handling multiplicity depend on the objectives and analysis plan. Since this is a single-group study and the record does not provide analysis results or a detailed testing plan, there is no basis for describing a particular adjustment or claiming that one was used.

The enrollment figure is 343, but the primary endpoint denominator and the number of participants with evaluable endpoint data are not reported in the registry record. The missing-data approach is also not reported in the registry record. It is therefore unknown from this record whether endpoint data were complete, whether any observations were excluded, or how missing observations would have been handled.

In general, missing outcome data can affect both the estimate and its interpretation, especially if the likelihood of missingness is related to participants’ responses. Without counts and reasons for missingness, readers cannot evaluate the potential impact. This is a limitation of the available reporting, not evidence that missing data did or did not occur in the study.

The analysis population is described for the primary endpoint as enrolled participants, but the record does not provide a participant flow or a more detailed definition of who contributed to the calculation. The listed safety risk set is reported separately and should not be assumed to be the primary endpoint denominator.

12. 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

Serious events with the highest arm-level rate: abortion spontaneous (0.3%).

The registry safety summary lists a DR-104 group with 299 participants at risk. In the serious-event fields, 1 is listed as affected; in the other-event fields, 0 is listed as affected. The most frequently listed serious term is “Abortion spontaneous,” with a reported value of 0.3%. These are the safety figures recorded for this group, and they should be read as registry summaries rather than as a complete safety analysis.

A serious adverse event is a classification based on seriousness criteria, not simply a judgment about how intense a symptom was. The record does not provide details about the event’s timing, clinical course, relatedness to treatment, or the method used to classify it. The event term alone does not establish that the study product caused the event. Causality information is not reported in the registry record.

The record lists zero in the other-event affected field, but that value does not establish that no adverse experiences of any kind occurred in all participants or throughout all possible follow-up. The safety denominator is 299, while overall enrollment is listed as 343; the reason for the difference is not reported in the registry record. The safety risk set should not be substituted for the primary endpoint population.

Deaths are not reported in the registry record. Further details on adverse-event collection, duration of surveillance, and participant-level event counts are not reported in the registry record. The available figures therefore support only a narrow description of the reported safety fields, not a broad assessment of safety.

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

The study asks whether adolescents requesting emergency contraception could appropriately select DR-104 after reading its label in a simulated over-the-counter setting. The endpoint is designed to measure a decision made at the Screening/Enrollment Visit, rather than a comparison of clinical outcomes. The registry gives enough information to identify that question and the intended summary measure, but it does not report the observed percentage or confidence-interval limits. The posted record therefore does not give the numerical answer to the primary question.

Even with a reported percentage, the result would need to be interpreted within the design’s scope. The participants were females 11-16 years of age, inclusive, requesting emergency contraception, and the scenario was simulated. The finding would describe the assessed participants and the specific label-based task, rather than every adolescent, every user, or every dispensing context. Generalization beyond the study population and setting would require additional evidence.

The endpoint also has a limited meaning. Appropriate self-selection concerns whether the participant made a suitable choice after reading the label. It is not equivalent to demonstrating correct performance of all steps of product use, establishing safety, or assessing treatment effectiveness. The study summary refers more broadly to appropriate and safe use without provider counseling, but those concepts should not be treated as interchangeable with the primary endpoint.

The single-group design does not support a claim that the product led to better or worse outcomes than another product, label, or counseling approach. No comparator group is described. The record also does not provide a randomized comparison or a numerical primary result from which to estimate a relative effect.

The listed safety figures are limited to the reported group summary and do not establish a causal relationship between the product and an event. The record does not report event details, follow-up duration, or deaths. Accordingly, neither an absence of reported numerical endpoint results nor a small listed event count should be converted into a claim about efficacy or overall safety.

The most defensible conclusion is descriptive: the registry specifies a label-guided self-selection question in a simulated setting, and records the study as completed, but the primary numerical outcome is not reported in the registry record. That gap prevents readers from assessing the observed performance or its statistical precision.

14. Why This Trial Matters Statistically

This trial is statistically notable for focusing on a behavioral and comprehension question rather than a conventional comparison of treatment outcomes. A label-based self-selection endpoint asks whether participants can apply information to their own situation in a simulated over-the-counter scenario. Such an endpoint can be relevant to understanding potential consumer decision-making, provided its definition and measurement process are clear.

The design makes the boundary of inference especially important. A single-group case series can describe responses within the enrolled group, but it cannot separate the observed pattern from outcomes under a different label, provider counseling, or another intervention. Readers must distinguish an assessment of a decision-making task from evidence about comparative treatment effects.

The record also illustrates why outcome definitions and numerical reporting must be considered together. The primary endpoint is described as a percentage with a 95% confidence interval, but the result and interval are not reported in the registry record. Without them, readers cannot evaluate either the magnitude of the observed response or its precision. A well-specified question is not a substitute for a reported estimate.

Safety summaries require similar care. The serious-event and other-event fields provide limited counts within a stated risk set, while the primary endpoint has no reported denominator. These populations and outcome types should not be conflated. Nor does an event term alone establish that the study product caused the event.

Finally, planning assumptions and the actual study design must remain distinct. The registry’s planning description refers to equal allocation between two arms, whereas the trial itself is recorded as single group with allocation not applicable. This contrast underscores that planning illustrations are not a substitute for the study’s design or an observed result. Statistically, the record is most useful for defining the question and clarifying the limits of what can be inferred from the posted information.

15. 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 most important reporting limitation is that the primary endpoint’s observed percentage and confidence-interval limits are not reported in the registry record. The numerator and the endpoint analysis denominator are also not reported. This prevents assessment of the result’s magnitude and precision, even though the endpoint definition and intended confidence level are described.

The record does not describe the criteria used to judge a self-selection decision as appropriate, the exact label-reading procedure, or the operational details of the simulated over-the-counter scenario. Those details are important for understanding what performance on the endpoint represents. The registry record does not report whether participants were assessed in a standardized manner beyond the description that they read the product label.

Enrollment is listed as 343, but participant flow, the number assessed for the primary endpoint, and reasons for any exclusions are not reported in the registry record. The safety summary has a risk set of 299, and the reason that this differs from the enrollment figure is not reported in the registry record. It should not be assumed that the safety set and primary endpoint population are the same.

The record describes a single-group study without a comparator. This limits causal interpretation and prevents direct comparison with an alternative product, label, or counseling condition. The simulated setting also limits how directly the endpoint can be generalized to routine use or other situations.

Further limitations of interpretation include the absence of a reported analysis plan, missing-data approach, and detailed safety follow-up information. The statistical methods used to calculate the stated confidence interval are not reported in the registry record. The record does not report event timing, relatedness, or deaths. These are gaps in the available registry reporting; they should not be interpreted as proof that the study did or did not collect such information.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Emergency Contraception Actual Use Study — NCT00777556.
• Registry record last updated 2012-10-18; status last verified 2012-09.
• Results first posted 2012-10-18.
• 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.

19. Record Summary

The registry describes NCT00777556, “Emergency Contraception Actual Use Study,” as a completed Phase 3, single-group, non-comparative case series sponsored by Duramed Research. Enrollment is listed as 343. The study began in 2008-10 and reached primary completion in 2010-12.

The study assessed DR-104, identified as Plan B® 1.5, among females 11-16 years of age, inclusive, requesting emergency contraception. The primary endpoint was the percentage appropriately self-selecting the product after label reading under simulated over-the-counter conditions at Day 1. A 95% confidence interval is named, but the numerical endpoint estimate and interval are not reported in the registry record.

The record lists secondary outcomes on treatment-emergent adverse events and repeat use of emergency contraception. Its safety summary lists 299 participants at risk, 1 affected in the serious-event field, 0 affected in the other-event field, and “Abortion spontaneous” at 0.3% among the serious terms. No comparator group is described, and the number of analyses is recorded as 0.