TCAD vs. Monotherapy for Influenza A in Immunocompromised Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for TCAD vs. Monotherapy for Influenza A in Immunocompromised Patients (NCT00867139), a randomized phase 1, phase 2 study. The primary outcome is Number of Participants With Adverse Events (AEs), Drug Specific AEs or AEs Resulting in Treatment Interruption.

2. Clinical Question

The study was designed to assess safety and tolerability of TCAD and to gain data on its effectiveness in this population. Its registry title identifies it as a pilot randomized study, and the listed primary outcome concerns adverse events through 30 days after the final dose of study drug. The secondary outcomes include measures of viral shedding and viral resistance, symptoms, pneumonia, hospitalization, supplemental oxygen, and ICU admissions.

The clinical question is therefore broader than whether one regimen is better than another. It includes whether the combination can be used and tolerated, alongside exploratory measures related to infection and clinical course. The registry record does not report a primary effectiveness outcome or an estimable comparison between the randomized groups.

3. Trial Design

This was a randomized, parallel-group, open-label study listed in Phase 1 and Phase 2. The record gives an enrollment of 7 and identifies influenza as the condition. The study start was 2009-03, primary completion was 2009-08, and its status is completed. Fred Hutchinson Cancer Center is listed as the sponsor.

The randomized arms were TCAD and neuraminidase inhibitor monotherapy. TCAD consisted of amantadine hydrochloride, ribavirin and oseltamivir phosphate; the monotherapy option was zanamivir or oseltamivir. The registry also lists an open-label TCAD arm for subjects who could not tolerate or were ineligible to receive zanamivir. That arm is distinct from the randomized TCAD arm in the posted results.

Open-label means the record does not describe masking of treatment assignment. The allocation is recorded as randomized, but the sequence-generation process, concealment procedures, and any stratification are not reported in the registry record. The record also does not explain how patients were assigned to the open-label arm, or how use of zanamivir versus oseltamivir was determined.

The small enrollment and multiple listed arms mean that the posted counts are descriptive, with very little information for comparing groups. The registry record does not report a sample-size justification, a recruitment flow, or details about withdrawals and treatment exposure. It also does not report protocol deviations or the number of participants contributing to each secondary outcome.

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 With Adverse Events (AEs), Drug Specific AEs or AEs Resulting in Treatment Interruption, measured over 30 days after the final dose of study drug.

The primary endpoint counts participants with adverse events (AEs), drug-specific AEs, or AEs resulting in treatment interruption. Its timeframe is 30 days after the final dose of study drug. The endpoint description says abnormal laboratory data or newly appeared symptoms and signs were considered AEs. The record lists laboratory monitoring across blood cell counts, chemistry, renal function, and liver function.

This kind of safety endpoint is used to describe whether adverse events were observed during a defined period after treatment. Counting participants with at least one event can summarize how many people were affected, but it does not by itself describe how many events each person experienced, their severity, or their duration. Nor does a count alone establish whether events were caused by a study drug.

The posted endpoint is expressed as a number of participants with AEs. The arm results list 1 participant in the TCAD arm, 1 in the neuraminidase inhibitor monotherapy arm, and 1 in the open-labeled TCAD arm. Those counts need to be read alongside the arm sizes and the fact that one arm was open-label rather than part of the randomized comparison. The registry record does not report further endpoint definitions, such as a detailed grading system or rules for attributing events to treatment.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The main endpoint is binary at the participant level: a participant either contributes to the count of those with the specified AE endpoint or does not. The results are posted as participant counts for each arm. A count is straightforward to understand, but the information it carries depends on how many participants were observed and how completely outcomes were collected. The arm sizes are especially important in this study because they are small and unequal.

What does an unestimable comparison mean?

The registry record says values were missing or not estimable for a two-arm comparison of this binary endpoint. In practical terms, the posted results do not yield a reported comparative estimate for the randomized arms. The record does not give the precise statistical reason that the comparison could not be estimated. It would therefore be speculative to attribute this to a particular model, continuity correction, or analysis rule.

General explanation: comparing binary outcomes usually involves estimating how event occurrence differs between groups, with uncertainty around that estimate. When group sizes and event counts are sparse, some methods may not produce a stable or finite estimate. The choice of method matters, and the registry record does not state which comparison method was planned or attempted. No numerical inferential result should be reconstructed from the participant counts alone.

Why do sparse counts matter?

General explanation: a small amount of observed data can make an estimate sensitive to each participant's outcome. A single event can have a large influence on a group summary when the group is small. Confidence intervals are used, when available, to show the range of effect estimates compatible with the data and the analysis assumptions. They do not remove uncertainty, and their interpretation depends on the method and design. No interval for the primary comparison is reported in the registry results.

The study has three reported arms, but only two are described as randomized treatment arms. The third is open-label TCAD for subjects who could not tolerate or were ineligible to receive zanamivir. A randomized comparison is intended to use the allocation process to support a fair comparison of assigned groups. The open-label arm has a different stated eligibility pathway, so combining it with either randomized arm would change the question and is not justified by the record.

What does the endpoint count capture?

The endpoint counts participants with AEs, drug-specific AEs, or AEs resulting in treatment interruption. It is a participant count, rather than a count of all AE episodes. A participant with several events may still appear once in a participant-level count. The record does not report a breakdown of the primary count by the endpoint's component categories, and it does not provide detailed event-level timing or severity information in the primary result.

The endpoint timeframe is 30 days after the final dose. This defines the stated period for collecting the primary safety outcome, but the record does not report how follow-up completion was assessed or how missing observations were handled. It also does not report whether event attribution was adjudicated or what criteria were used to identify drug-specific events.

What can the other analyses tell us?

The listed secondary outcomes cover virologic measures and clinical course, including viral-load change, viral shedding, resistance, symptoms, pneumonia, hospitalization, oxygen use, and ICU admission. These outcomes would address different questions and may have different measurement scales and analysis requirements. For example, a count of participants not shedding virus at a specified assessment differs from a duration outcome. The registry record does not report analysis methods or results for these outcomes in the data summarized for this analysis.

General explanation: when many outcomes are examined, the chance of finding an apparently unusual result by chance can rise if each is tested separately without accounting for the set of tests. Multiplicity methods can control or describe that issue, but the record does not report a multiplicity strategy. It is not possible to determine from the listed outcome names alone whether any adjustments were planned.

Sample-size calculations, when presented as planning illustrations, answer a different question from the observed trial results. They describe the group size that would be needed under stated assumptions to detect an effect of a specified size. They are not observed power and do not change the precision of the results already collected. The registry record's design assumptions for such illustrations do not establish that the trial itself used those calculations; the trial's own sample-size justification is not reported in the registry record.

More broadly, no full statistical analysis plan, model specification, interim analysis plan, or definition of analysis populations is reported in the registry record. These omissions limit the ability to assess whether the posted outcome summaries follow prespecified procedures. Interpretation should therefore remain with the descriptive participant counts and the registry's explicit note that a two-arm comparison was not estimable.

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("TCAD", "Neuraminidase Inihibitor Monotherapy", "Open-labeled TCAD")
n      <- c(2, 1, 4)
events <- c(1, 1, 1)
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  TCAD  2  1  50.0  1.3  98.7  9.5  90.5  9.4  90.6
ARM  Neuraminidase Inihibitor Monotherapy  1  1  100.0  2.5  100.0  20.7  100.0  15.8  98.7
ARM  Open-labeled TCAD  4  1  25.0  0.6  80.6  4.6  69.9  5.3  71.6

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists 12 outcome measures, including the primary AE endpoint and 11 secondary outcomes. The secondary outcomes span virologic outcomes, symptoms, pneumonia, hospitalization, supplemental oxygen, and ICU admissions. With multiple outcomes, separate statistical tests can create a multiplicity issue: general statistical practice recognizes that testing many questions can increase the chance of an apparently notable result arising by chance. The registry record does not report whether any multiplicity adjustment or hierarchy of outcomes was planned.

The analysis count is recorded as 0. The record does not provide a statistical analysis plan, identify which secondary outcomes were analyzed, or state whether analyses were prespecified. No outcome-specific missing-data rules, imputation method, or sensitivity analysis is reported in the registry record. The registry record also does not describe the handling of participants who stopped treatment, were lost to follow-up, or had incomplete outcome measurements.

The analysis population is not reported in the registry record. In particular, it does not specify whether the primary summary includes all randomized participants, only participants who received treatment, or another defined group. The registry record does not provide a participant flow or enough detail to determine how the listed arm sizes relate to completion of each assessment.

These gaps matter because missing observations and analysis-population choices can affect what a participant count represents. The posted results should be treated as registry summaries, not as a complete account of the analysis process. No assumption about intention-to-treat analysis, per-protocol analysis, or other population definitions is warranted.

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: acute gvhd (100.0%), ards (25.0%).

The serious adverse event summaries list 1 affected participant among 2 at risk in the TCAD arm, 1 among 1 in the neuraminidase inhibitor monotherapy arm, and 1 among 4 in the open-labeled TCAD arm. The record also lists other adverse events for 1 participant among 2 at risk in the TCAD arm, 0 among 1 in monotherapy, and 0 among 4 in open-labeled TCAD. These counts are descriptive and do not establish that a treatment caused an event.

The listed top serious-event terms are Acute GVHD at 100.0% and ARDS at 25.0%. The denominator and the precise basis for these percentages are not reported in the registry record. They should not be interpreted as percentages of all participants in a treatment arm without that information. The record does not provide enough detail to determine whether terms overlap or how events were distributed across arms.

Deaths are not reported in the registry record. Serious adverse events, other adverse events, and deaths are distinct safety summaries; one should not infer one category from another. The small arm sizes and limited event detail mean these figures are best read as a record of reported events, not as comparative risk estimates.

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

The posted primary outcome indicates that participants with AEs were recorded in each of the three arms. The values are participant counts, and the results include a randomized TCAD arm, a randomized neuraminidase inhibitor monotherapy arm, and a separate open-labeled TCAD arm. The registry record reports that values for a two-arm comparison were missing or not estimable, so the primary results do not quantify a comparative difference.

This does not establish equivalence between TCAD and monotherapy, nor does it show that one regimen has more or fewer AEs in a way that can be generalized. The small groups leave substantial uncertainty, and the comparison is not reported as an inferential estimate. The open-labeled arm also has a different stated eligibility pathway, so it is not interchangeable with either randomized arm.

The results do not establish effectiveness. Although the study purpose included gaining data on TCAD effectiveness and the secondary outcomes included virologic and clinical measures, those outcomes do not have analysis results reported in the information. No conclusion about viral clearance, symptom duration, pneumonia, hospitalization, oxygen use, ICU admission, or resistance can be drawn from the posted primary safety counts.

General explanation: an absence of a reported statistical difference is not the same as evidence that treatments have the same effects. Equivalence or non-inferiority requires a defined question and analysis, including a prespecified margin. Such a margin and analysis are not reported in the registry record. Similarly, a participant-level AE count does not show causality, severity, or the balance of potential benefits and harms.

The appropriate interpretation is limited: these are pilot-study registry results describing participant counts and selected serious-event summaries. The lack of a reported comparative estimate, the limited scale of the groups, and missing analysis details prevent a reliable claim about comparative safety or effectiveness.

14. Why This Trial Matters Statistically

This trial is statistically informative as an example of the difference between collecting an outcome and being able to estimate a treatment contrast. The registry record has an explicit primary safety endpoint and arm-level participant counts, but it does not report an estimable two-arm comparison. A defined endpoint alone does not guarantee a precise or interpretable comparative result, particularly when groups are very small.

The design also illustrates why arm structure matters. Two groups are identified as randomized, while the open-labeled TCAD arm was for subjects who could not tolerate or were ineligible to receive zanamivir. Those groups address different comparisons. Treating all arms as if they arose from the same random assignment would ignore the pathway described in the record.

The trial's pilot status and its combination of safety, tolerability, pharmacokinetic, virologic, and clinical outcomes make careful separation of questions important. The primary endpoint is about recorded adverse events, whereas the secondary outcomes address other aspects of infection and clinical course. Without posted analyses for those outcomes, the existence of a measure should not be confused with evidence of a result.

For biostatisticians and clinical researchers, the record underscores the value of reporting analysis populations, missing-data procedures, endpoint definitions, and estimates with uncertainty. These details help readers distinguish a descriptive count from a comparative conclusion and understand what the data can support. In this case, the main statistical message is the limited precision and the absence of an estimable primary two-arm result, rather than a definitive ranking of treatments.

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 gives limited detail about the study population beyond immunocompromised patients with influenza A. Eligibility criteria, baseline characteristics, disease severity, and other clinical descriptors are not reported in the registry record. This makes it difficult to assess how broadly the participants represent the intended population.

Although allocation is recorded as randomized, randomization methods, allocation concealment, and the process for selecting zanamivir or oseltamivir are not reported. The open-label arm had a stated eligibility condition that differs from the randomized comparison. The record does not explain assignment procedures for that arm or provide enough detail to assess potential differences between those participants and the randomized groups.

The endpoint description identifies abnormal laboratory data and newly appeared symptoms and signs as AEs and lists categories of laboratory tests. It does not report detailed grading criteria, event attribution procedures, or a breakdown of the primary participant count by event type. Follow-up is stated as 30 days after the final dose, but completeness of follow-up and handling of missing observations are not reported in the registry record.

The record does not report a sample-size justification, statistical analysis plan, analysis populations, or multiplicity strategy. It also does not provide analysis results for the listed secondary outcomes in the information. The primary comparison is explicitly not estimable in the registry results. Together, these limitations restrict interpretation to descriptive safety counts and preclude firm comparative conclusions.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: TCAD vs. Monotherapy for Influenza A in Immunocompromised Patients — NCT00867139.
• Registry record last updated 2013-08-15; status last verified 2013-08.
• Results first posted 2013-06-04.
• 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

NCT00867139 is a completed Phase 1 and Phase 2 randomized, parallel, open-label pilot study sponsored by Fred Hutchinson Cancer Center. It enrolled 7 immunocompromised patients with influenza A, with a study start of 2009-03 and primary completion in 2009-08.

The study compared TCAD (amantadine, ribavirin and oseltamivir) with neuraminidase inhibitor monotherapy (zanamivir or oseltamivir) and also listed an open-label TCAD arm for subjects unable to tolerate or ineligible for zanamivir. The primary outcome counted participants with AEs, drug-specific AEs, or AEs resulting in treatment interruption through 30 days after the final dose.

Posted primary counts were 1 participant in the TCAD arm, 1 in monotherapy, and 1 in open-labeled TCAD. The registry record states that a two-arm comparison was not estimable. It lists 11 secondary outcomes, but no analyses are recorded. The results support descriptive reading only and do not establish comparative safety or effectiveness.