PegIntron Injection Surveillance Plan (Study P04123): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for PegIntron Injection Surveillance Plan (Study P04123) (NCT00723931), a registered phase not stated study. The primary outcome is Number of Participants That Reported a Serious Adverse Event.

2. Clinical Question

3. Trial Design

This record describes a completed postmarketing surveillance plan titled PegIntron Injection Surveillance Plan (Study P04123). Its stated purpose was to assess safety and efficacy under actual conditions of use and to examine adverse events, serious adverse events, and adverse drug reactions. The condition is chronic hepatitis C, and the listed intervention is peginterferon alfa-2b (SCH 54031). The adverse-event group is titled Pegintron/Pegintron Redipen Injection.

The surveillance setting was digestive departments of internal medicine in university or general hospitals where participants with chronic hepatitis C were generally treated. The registry lists enrollment of 1267 and a status of completed. The recorded start is 2006-06 and primary completion is 2009-11. These dates identify the registry milestones; further details about recruitment, follow-up operations, or the timing of individual participant visits are not reported in the registry record.

No randomized allocation or comparator is described. The registry explicitly says allocation is not stated and that the arms are not a like-for-like control comparison. Consequently, the listed results are descriptive surveillance findings, not a randomized estimate of a difference between treatments. Details such as a protocol-defined control strategy, blinding, or a planned comparative analysis are not reported in the registry record.

The record lists two outcome measures and no registered analyses. The primary outcome is the number of participants reporting a serious adverse event during the 24 weeks after administration. The registry record does not provide a statistical analysis plan, a sample-size justification, or additional design details that would establish how the surveillance enrollment was chosen.

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.

Overall Study

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 That Reported a Serious Adverse Event, measured over 24 weeks after administration of PegIntron Injection.

The primary endpoint is the number of participants who reported a serious adverse event during the 24 weeks after PegIntron Injection administration. The registry defines serious events as those resulting in death, being life threatening, requiring hospitalization, causing disability, or involving congenital anomaly. It states that serious adverse events related or unrelated to the study drug were reported, along with events determined by the investigator using specific criteria defined in the protocol.

This endpoint is used to describe serious safety events observed during surveillance. It is a participant count, not a count of all event episodes: a participant could in principle have more than one event, but the record does not provide event-level totals or detail on repeat events. The posted endpoint therefore answers how many participants were recorded as reporting an event meeting the stated seriousness criteria, rather than how many individual event episodes occurred.

In general, reporting a participant count alongside the number at risk helps readers understand the scope of a descriptive result. It does not by itself explain whether all participants had complete follow-up, how events were verified, or how an event’s relationship to the drug was adjudicated. Those operational details are not reported in the registry record. Nor does this endpoint alone measure efficacy; although the surveillance purpose mentions efficacy, the registry record does not identify an efficacy result in the information available for this analysis.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What kind of outcome is this?

The primary result is a binary participant-level outcome expressed as a count: each participant is classified according to whether a serious adverse event was reported during the stated timeframe. In general, a binary outcome records whether an event or condition is present, rather than measuring a continuous quantity such as a laboratory value. Reporting the number of participants with the event is a straightforward way to describe the observed records. Interpretation also depends on knowing the population and follow-up underlying the count.

The primary endpoint names participants, not event episodes. That distinction matters in safety surveillance. One participant may potentially experience more than one serious event, but a participant count does not reveal the number of episodes. The registry record does not provide individual event histories, event totals, or a description of whether repeat events were handled in any particular way.

How should the denominator be read?

The serious adverse event result gives 15 participants with an event and 1267 at risk. The other-adverse-event result gives 820 participants with an event and 1267 at risk. These are the posted counts and denominators; no further arithmetic is needed to describe them. In general, a denominator indicates the group against which an event count is interpreted. It does not establish that every participant had complete observation for the entire timeframe, nor does it show how missing outcome information was handled. Follow-up completeness and missing-data procedures are not reported in the registry record.

The registry reports the primary timeframe as 24 weeks after administration of PegIntron Injection. A defined timeframe is important because event counts depend on how long participants are observed. The record does not provide further details about the exact start and end of observation for each participant, whether follow-up differed across participants, or how events occurring outside that timeframe were treated.

What does a count establish?

A count establishes how many participants the posted results classify as having the outcome under the record’s reporting process. It does not by itself establish an event’s cause. The endpoint description says related and unrelated serious adverse events were reported. It also says that events determined by the investigator using criteria defined in the protocol were reported. The registry record does not provide the criteria themselves, the adjudication process, or a breakdown by relationship to the study drug.

In general, estimates based on a sample have uncertainty. A confidence interval is a range calculated by a statistical method to express uncertainty around an estimate; it is not a guarantee that the true value falls within that range. No confidence interval or other uncertainty interval for the primary result is reported in the registry record. Without such an interval, readers cannot use the posted result to assess its statistical precision in the same way they could with an interval estimate.

Why is a comparison not available?

The record lists a surveillance group and no comparator. It states that this was not a randomized comparison, that allocation is not stated, and that arms are not a like-for-like control comparison. In general, a comparison group can help distinguish outcomes associated with an intervention from outcomes that might also occur without it, though the strength of that distinction depends on study design and analysis. No such treatment contrast is reported for this result. The count should therefore be interpreted descriptively, not as an estimate of excess risk or a causal effect.

The primary outcome is not accompanied by a registered analysis in the available record. No p-value or comparative estimate is reported. A p-value, in general, summarizes how compatible data are with a specified statistical model and null hypothesis; it does not measure clinical importance or prove causation. Since no p-value is reported, none can be inferred from the participant count alone.

How should planning calculations be distinguished from observed results?

In general, a sample-size calculation is a planning exercise about how many participants may be needed to detect a specified effect under stated assumptions. It is not a result observed in the surveillance data and does not establish that a study had a particular probability of detecting an effect after completion. The registry record describes planning illustrations based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. It also distinguishes participant-per-arm outputs from total-event outputs for time-to-event calculations.

Those planning assumptions do not turn this surveillance record into a randomized two-arm comparison. The record does not state allocation, and it cautions that the arms are not a like-for-like control comparison. The planning illustrations are therefore not evidence of observed power, and they should not be read as a substitute for an analysis plan or as a basis for causal interpretation. The registry record does not report a sample-size justification for the surveillance itself.

What is not specified?

The registry record lists no analyses. It does not report the statistical model or method used to produce the posted event counts, a prespecified analysis population, missing-data rules, confidence intervals, or adjustment for multiple outcomes. General statistical methods can clarify what these items would mean, but their absence prevents conclusions about whether particular procedures were applied. The posted counts remain interpretable as recorded descriptive results, with the limits set by the information reported.

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("Pegintron/Pegintron Redipen Injection")
n      <- c(1267)
events <- c(15)
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  Pegintron/Pegintron Redipen Injection  1267  15  1.2  0.7  1.9  0.7  1.9  0.7  1.9

11. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures and no registered analyses. The primary outcome is the participant count for serious adverse events during the 24 weeks after administration. The other outcome’s title, definition, timeframe, and result are not reported in the registry record available for this analysis. A multiplicity strategy—such as whether outcomes were treated as separate descriptive measures or whether inferential testing was adjusted—is also not reported.

In general, multiplicity arises when several outcomes or hypotheses are considered. If many statistical tests are conducted, the chance of a nominally unusual result can increase; methods for addressing this depend on the study question and analysis plan. That general concern does not establish that multiple tests were performed in this surveillance record. No registered analyses are listed, so the record does not support a claim that a particular correction was or was not applied in an unreported analysis.

Missing-data handling is not reported in the registry record. The outcome population field is blank, and the record does not describe losses to follow-up, the amount of missing outcome information, or how participants with incomplete observation were treated. The at-risk denominator alone does not establish complete follow-up for every participant throughout the stated timeframe.

The analysis population is likewise not reported. In general, an analysis population specifies which participants contribute to a result and under what criteria. The registry’s enrollment and at-risk count describe the posted record, but no additional population definition should be inferred from them. These omissions limit assessment of the completeness and prespecification of the outcome analysis.

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

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: haemoptysis (0.2%), anaemia (0.1%), atrial fibrillation (0.1%), cardiac failure (0.1%), haemorrhoids (0.1%).

The primary serious adverse event result is 15 participants with a reported event among 1267 at risk in the Pegintron/Pegintron Redipen Injection group. The timeframe is 24 weeks after administration. The registry defines serious events to include death, life-threatening events, hospitalization, disability, and congenital anomaly. It states that related and unrelated serious adverse events were reported. The result is therefore a participant count under the registry’s reporting definition, not a count limited to events attributed to the injection.

The record separately reports 820 participants with other adverse events among 1267 at risk. The relationship between this group and the serious-event group is not stated; the counts should not be combined. The record’s deaths field is null, so deaths are not reported in the registry record as a separate result. A null entry should not be interpreted as evidence that no deaths occurred.

The listed serious terms and their displayed percentages are Haemoptysis (0.2%), Anaemia (0.1%), Atrial Fibrillation (0.1%), Cardiac Failure (0.1%), Haemorrhoids (0.1%), and Nausea (0.1%). Term-specific counts and the basis for those percentages are not reported in the registry record. These displayed terms do not provide a complete account of all events or their relationship to the study drug.

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

The posted results describe adverse events recorded in a completed postmarketing surveillance plan for people with chronic hepatitis C receiving the listed intervention. The primary result is a count of participants reporting a serious adverse event within the specified timeframe. The separate count for other adverse events adds descriptive information about events recorded in the surveillance group. These results can help characterize what was reported in this record under its stated definitions.

They do not establish that the intervention caused every reported event. The primary endpoint includes serious events related or unrelated to the study drug, and the registry does not provide a relationship-specific breakdown. They also do not establish that any event was caused by the underlying condition or by another factor. No causal attribution should be inferred from a descriptive count alone.

The results do not show how event frequency compares with no treatment or with another treatment. No comparator is listed, allocation is not stated, and the registry cautions that the arms are not a like-for-like control comparison. There is no reported comparative effect estimate, confidence interval, or p-value for the primary endpoint. Thus, the event counts cannot be used to estimate a treatment difference or determine the statistical precision of such a difference.

The surveillance purpose includes efficacy, but the primary endpoint described in the record is a safety outcome. The efficacy result and its definition are not reported in the registry record available for this analysis. The safety count alone therefore does not answer an efficacy question.

In general, interpretation of a surveillance result depends on how participants were selected, how outcomes were collected, completeness of follow-up, and how events were classified. The registry record gives the setting, outcome definition, timeframe, and posted counts, but does not report all those operational details. The results should be understood within that reporting scope and not extended automatically to other populations, settings, or follow-up periods.

14. Why This Trial Matters Statistically

Postmarketing surveillance addresses a different statistical question from a randomized treatment comparison. Its purpose in this record was to examine safety and efficacy under actual conditions of use and to record adverse events, serious adverse events, and adverse drug reactions. A descriptive account of reported events can be useful for understanding what was captured in that setting, even when it cannot estimate a causal treatment contrast.

The primary endpoint makes an important distinction between a serious event and an event that is simply reported as adverse. The registry describes seriousness using consequences such as death, life-threatening status, hospitalization, disability, or congenital anomaly. It also states that events related and unrelated to the study drug were included. Those definitions help readers understand what the count represents, while the missing relationship-specific detail limits conclusions about attribution.

Statistically, the record illustrates why counts need context. The 15-participant serious adverse event result is accompanied by an at-risk denominator of 1267 and a stated 24-week timeframe. The additional adverse-event count uses the same stated denominator. Together these details identify the reported scope, but they do not resolve questions about complete follow-up, missing outcomes, or event adjudication. No confidence interval or comparative analysis is reported, so precision and between-group differences cannot be evaluated from the registry record.

The record also highlights the boundary between surveillance and comparative inference. Without a like-for-like control comparison, the observed counts describe events in the listed group; they do not isolate the contribution of the intervention. The registry’s explicit caution about the arms is particularly relevant when interpreting any planning illustration based on an observed effect: planning assumptions are not equivalent to a randomized design or evidence of observed power.

These distinctions matter for biostatisticians and clinical researchers because they keep the interpretation aligned with the design and reporting. The value of the record is its documented surveillance context and event counts, while its limitations preclude stronger claims about causality, comparative safety, or efficacy.

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 registry record does not describe a comparator or randomized allocation. It explicitly notes that allocation is not stated and that the arms are not a like-for-like control comparison. As a result, the serious adverse event count cannot establish a treatment contrast or support a causal estimate relative to another strategy.

The primary outcome population field is blank. Although the record lists enrollment of 1267 and gives 1267 at risk for the adverse-event results, it does not describe the analysis population or establish whether all participants had complete observation for the full 24 weeks. Follow-up completeness, missing-data handling, and reasons for any incomplete outcome information are not reported in the registry record.

Further detail about outcome ascertainment is limited. The registry gives its seriousness criteria and notes investigator determination using protocol-defined criteria, but the criteria and adjudication procedures are not reproduced in the available record. It does not report event-level counts, a relationship-to-drug breakdown, or the basis for the displayed percentages attached to the listed serious terms. The deaths field is null, rather than a reported count.

The record lists two outcome measures but gives no registered analyses. A statistical analysis plan, confidence intervals, comparative estimates, p-values, and multiplicity procedures are not reported. The second outcome’s details are also not available. These gaps prevent a full assessment of prespecification, statistical precision, and the completeness of outcome reporting.

The surveillance setting is described, but additional information on participant selection and the operational conduct of follow-up is not reported in the registry record. These limitations do not invalidate the posted counts; they define what those counts can support: a descriptive account of the events recorded, without broader comparative or causal conclusions.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: PegIntron Injection Surveillance Plan (Study P04123) — NCT00723931.
• Registry record last updated 2015-11-04; status last verified 2015-11.
• Results first posted 2010-12-13.
• 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

NCT00723931 is the completed PegIntron Injection Surveillance Plan (Study P04123), sponsored by Merck Sharp & Dohme LLC. The condition is chronic hepatitis C. The listed intervention is peginterferon alfa-2b (SCH 54031), and enrollment is recorded as 1267. The registry lists a start of 2006-06 and primary completion of 2009-11.

The primary outcome is the number of participants reporting a serious adverse event during the 24 weeks after administration. The posted result records 15 participants with a serious adverse event among 1267 at risk, and 820 participants with other adverse events among 1267 at risk. The record lists two outcome measures and no registered analyses.

This is a surveillance record, not a randomized comparison. Allocation is not stated, and the registry cautions that the arms are not a like-for-like control comparison. Comparative estimates, confidence intervals, missing-data procedures, and detailed analysis populations are not reported in the registry record. The posted counts are descriptive and do not establish causation or comparative efficacy.